US20110257723A1 - Devices and methods for coronary sinus pressure relief - Google Patents

Abstract

A method and devices for relieving pressure in the left atrium of a patient's heart is disclosed. The method includes using an ablative catheter in a minimally invasive procedure to prepare an opening from the coronary sinus into a left atrium of the patient's heart. Once the opening is prepared, the opening may be enlarged by a technique such as expanding a balloon within the opening. A stent is then placed within the coronary sinus of the patient, with a transverse portion expanding within the opening, allowing blood to flow from the left atrium to the coronary sinus and then to the right atrium. Pressure within the left atrium is thus relieved.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a non-provisional of U.S. Provisional Appl. 61/449,566, filed Mar. 4, 2011 entitled DEVICES AND METHODS FOR CORONARY SINUS PRESSURE RELIEF. This application is also a continuation-in-part of copending U.S. Nonprovisional patent application Ser. No. 12/954,468, filed on Nov. 24, 2010, entitled MOUNTING TOOL FOR LOADING A PROSTHESIS, which is incorporated herein by reference in its entirety. U.S. Nonprovisional patent application Ser. No. 12/954,468 application claims the benefit of U.S. Provisional Patent Application having Ser. No. 61/240,085 entitled DEVICES AND METHODS TO TREAT HEART FAILURE filed Sep. 4, 2009, the entirety of which is incorporated herein by reference. U.S. Nonprovisional patent application Ser. No. 12/954,468 is also a continuation-in-part of copending U.S. Nonprovisional patent application Ser. No. 12/719,843, filed on Mar. 8, 2010, entitled DEVICES, SYSTEMS AND METHODS TO TREAT HEART FAILURE, and also claims priority to U.S. Provisional Application Ser. No. 61/299,559, filed on Jan. 29, 2010, entitled SYSTEMS, METHODS AND DEVICES FOR CATHETER-BASED DELIVERY OF IMPLANTABLE DEVICES, both of which are hereby incorporated by reference in their entirety. U.S. Nonprovisional patent application Ser. No. 12/719,843 is a continuation-in-part of copending U.S. Nonprovisional patent application having Ser. No. 12/447,617, entitled DEVICES AND METHODS FOR THE TREATMENT OF HEART FAILURE filed Apr. 28, 2009, which is incorporated herein by reference in its entirety. U.S. Nonprovisional patent application having Ser. No. 12/447,617 was submitted under 35 U.S.C.§371 and thus claims priority to international application PCT/AU2007/001704 entitled DEVICES AND METHODS FOR TREATMENT OF HEART FAILURE filed Nov. 7, 2007, which is incorporated herein by reference in its entirety. PCT/AU2007/001704 claims priority to Australian Patent Application No. AU 2006906202 filed Nov. 7, 2006, which is incorporated herein by reference in its entirety.
FIELD
• The present disclosure relates generally to devices and methods for treating heart failure. In particular, the disclosure relates to interatrial pressure vents, shunts and the like, which reduce elevated pressure on one side of the heart thus mitigating the symptoms that result, as well as placement devices, systems, and methods therefore.
BACKGROUND
• Heart failure is a common and potentially lethal condition affecting humans, with sub-optimal clinical outcomes often resulting in symptoms, morbidity and/or mortality, despite maximal medical treatment. In particular, “diastolic heart failure” refers to the clinical syndrome of heart failure occurring in the context of preserved left ventricular systolic function (ejection fraction) and in the absence of major valvular disease. This condition is characterized by a stiff left ventricle with decreased compliance and impaired relaxation, which leads to increased end-diastolic pressure. Approximately one third of patients with heart failure have diastolic heart failure and there are very few, if any, proven effective treatments.
• Symptoms of diastolic heart failure are due, at least in a large part, to an elevation in pressure in the left atrium. In addition to diastolic heart failure, a number of other medical conditions, including systolic dysfunction of the left ventricle and valve disease, can lead to elevated pressures in the left atrium. Increased left atrial pressure often causes acute or chronic breathlessness amongst other problems. In addition, a variety of heart conditions can lead to “right heart failure”, which can result in enlargement of the liver (hepatomegaly), fluid accumulation in the abdomen (ascites) and/or swelling of the lower limbs.
• Frequently, patients with diastolic heart failure experience breathlessness due, in part, to elevated pulmonary venous pressure. These patients often feel worse when supine than when sitting or standing, implying that small changes in pulmonary venous pressure have a pronounced effect on symptoms.
• In the past, strategies have been described for the relief of high pressure in the right atrium, such as the creation of hole(s) in the native or surgically created septum between the left and right atria. These have been designed for the rare conditions of pulmonary hypertension or cavopulmonary connections for certain complex congenital heart diseases.
• The functioning of the heart and the opening and closing of heart valves occur primarily as a result of pressure differences. For example, the opening and closing of the mitral valve between the left atrium and the left ventricle occurs as a result of the pressure differences between the left atrium and the left ventricle. During ventricular diastole (ventricular filling), when ventricles are relaxed, the venous return of blood from the pulmonary veins into the left atrium causes the pressure in the atrium to exceed that in the ventricle. As a result, the mitral valve opens, allowing blood to enter the ventricle. As the ventricle contracts during ventricular systole (ventricular emptying), the intraventricular pressure rises above the pressure in the atrium and pushes the mitral valve shut. Blood then is pumped from the ventricles to the arteries.
• The heart has four valves to ensure that blood does not flow in the wrong direction during the cardiac cycle; that is, to ensure that the blood does not back flow from the ventricles into the corresponding atria, or back flow from the arteries into the corresponding ventricles. The valve between the left atrium and the left ventricle is the mitral valve. The valve between the right atrium and the right ventricle is the tricuspid valve. The pulmonary valve is at the opening of the pulmonary artery. The aortic valve is at the opening of the aorta.
• Blood flowing back from the left ventricle into the left atrium, or systolic dysfunction of the left ventricle and valve disease, as mentioned in the background, may cause high atrial pressure and reduce the flow of blood into the left atrium from the lungs. As blood backs up into the pulmonary system, fluid leaks into the lungs and causes pulmonary edema. Blood volume going to the atrium reduces volume of blood going forward into the aorta causing low cardiac output. Excess blood in the atrium over-fills the ventricle during each cardiac cycle and causes volume overload in the left ventricle.
• Heart failure with such symptoms is a common and potentially lethal condition affecting humans, with sub-optimal clinical outcomes often resulting in symptoms, morbidity and/or mortality, despite maximal medical treatment. In particular, “diastolic heart failure” refers to the clinical syndrome of heart failure occurring in the context of preserved left ventricular systolic function (ejection fraction) and in the absence of major valvular disease. This condition is characterized by a stiff left ventricle with decreased compliance and impaired relaxation, which leads to increased end-diastolic pressure. Approximately one third of patients with heart failure have diastolic heart failure and there are very few, if any, proven effective treatments.
• Symptoms of diastolic heart failure are due, at least in a large part, to an elevation in pressure in the left atrium. In addition to diastolic heart failure, a number of other medical conditions, including systolic dysfunction of the left ventricle and valve disease, can lead to elevated pressures in the left atrium. Increased left atrial pressure often causes acute or chronic breathlessness amongst other problems. In addition, a variety of heart conditions can lead to “right heart failure”, which can result in enlargement of the liver (hepatomegaly), fluid accumulation in the abdomen (ascites) and/or swelling of the lower limbs.
• Frequently, patients with diastolic heart failure experience breathlessness due, in part, to elevated pulmonary venous pressure. These patients often feel worse when supine than when sitting or standing, implying that small changes in pulmonary venous pressure have a pronounced effect on symptoms.
• In the past, strategies have been described for the relief of high pressure in the right atrium, such as the creation of hole(s) in the native or surgically created septum between the left and right atria. These have been designed for the rare conditions of pulmonary hypertension or cavopulmonary connections for certain complex congenital heart diseases. Accordingly, there still exists a need for devices and methods to treat heart failure, particularly diastolic and/or systolic failure of the left ventricle and its consequences.
• Furthermore, there also still exists a need for devices to relieve high pressure in the left atrium and which will prevent or minimize the chance of the passage of thrombi and the resulting risk of systemic emboli.
BRIEF SUMMARY
• One embodiment is a stent for use in a patient. The stent includes a plurality of struts and a plurality of intersections joining the struts to form a stent having a longer cylindrical portion and a shorter cylindrical portion adjacent the longer cylindrical portion and extending beyond the longer cylindrical portion in a direction perpendicular to an axis of the longer cylindrical portion, wherein the longer cylindrical portion is adapted to fit into and bear against a coronary sinus and wherein the stent is adapted to form an opening from the coronary sinus to a left atrium of the patient.
• Another embodiment is a stent for use in a patient. The stent includes a longer, radially-expanding portion adapted for placement in a coronary sinus of the patient and a shorter portion adjacent and joined to the longer, radially-expanding portion, the shorter portion extending beyond the longer, radially-expanding portion in a direction perpendicular to an axis of the longer radially-expanding portion, the shorter portion adapted for placement within a left atrium of the patient, wherein the longer, radially-expanding portion is adapted to bear against a wall of the coronary sinus and wherein the shorter portion is adapted to form an opening between the left atrium and the coronary sinus of the patient.
• Another embodiment is a method for relieving intracardial pressure. The method includes steps of providing an opening between a left atrium of a heart and a coronary sinus and allowing blood to flow from the left atrium into the coronary sinus.
• Another embodiment is a method for relieving intracardial pressure. The method includes steps of furnishing a stent suitable for implantation into a coronary sinus of a patient, the stent suitable for extending from the coronary sinus to within a left atrium of the patient and for maintaining communication between the left atrium and the coronary sinus, preparing an opening in the left atrium using at least one instrument in the coronary sinus, maneuvering the stent into the coronary sinus to a position near the opening, and deploying a portion of the stent into the opening, wherein the stent maintains communication between the left atrium and the coronary sinus.
• Another embodiment is also a method for relieving intracardial pressure. The method includes steps of furnishing a stent suitable for implantation into coronary sinus of a patient, the stent suitable for extending from the coronary sinus to within a left atrium of the patient and maintaining for communication between the left atrium and the coronary sinus, preparing an opening in a wall between the left atrium and the coronary sinus, maneuvering the stent to a position near the opening, and deploying the stent into the opening, wherein the stent maintains communication between the left atrium and the coronary sinus.
• These and other needs are met by providing an opening between the left atrium and the coronary sinus to provide communication between the left atrium and the coronary sinus, enabling the relief of pressure in the left atrium. Other needs are met by providing within the opening a venting device, a prosthesis, within the opening between the left atrium and the coronary sinus.
• Yet other needs are met by providing within the opening a venting device, a prosthesis, such as an interatrial pressure vent, which in some embodiments comprises a controlled opening or an extended tubular opening, between the left atrium and right atrium that allows an amount of blood to vent from the left heart to the right heart, thereby reducing left atrial pressure and the symptoms associated with diastolic heart failure.
• Several unique intracardiac pressure vents, placement catheters, methods of placement and methods of treating heart failure are presented. The intracardiac pressure vents or prostheses presented allow sufficient flow from the left atrium to the right atrium to relieve elevated left atrial pressure and resulting patient symptoms but also limit the amount of flow from the right atrium to the left atrium to minimize the potential for thrombi or other embolic material from entering the arterial circulation.
• In addition, the intracardiac pressure vents or prostheses presented solve the problem of controlling flow in one direction but minimizing flow in another direction with very low changes in pressure across the device.
• Also, the intracardiac pressure vents presented solve the problem of reducing calcium deposition, protein deposition and thrombi formation in a low pressure environment.
• Furthermore, the intracardiac pressure vents presented solve the problem of damage to the interatrial septum as well as the rest of the left atrium from excessive pressure against the wall which can cause injury to the tissue and possibly adverse reaction by the patient or compromised function to the interatrial pressure vent.
• In addition, atrial arrhythmias are frequently seen in patients with heart failure and may, in part, be caused by chronically elevated left atrial pressure. Therefore, relief of elevated left atrial pressure may lead to reduction of atrial fibrillation.
• The present disclosure provides prostheses, that is, interatrial pressure vents, along with placement catheters, methods for placing a device in the interatrial septum within the heart of a patient and methods for treatment of the symptoms of heart failure, particularly diastolic heart failure.
• In embodiments, the interatrial pressure vent or prosthesis comprises a body assembly and a flow control element; the body assembly comprises a flexible, substantially open mesh adapted for use in a patient. The flow control element attaches to at least one point of the body assembly and the flow control element provides greater resistance to flow in one direction than it does in another direction.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element; the body assembly comprises a flexible, substantially open mesh adapted for use in a patient. The flow control element attaches to at least one point of the body assembly and is at least partially open to flow when there is no pressure differential across the flow control element.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element; the body assembly comprises a core segment and at least one flange segment; the flange segment is integral with, or attached to at least one point adjacent to, an end of the core segment; the flange segment extends radially outward from the center longitudinal axis of the core segment. The flow control element attaches to at least one point along the core segment and the flow control element provides greater resistance to flow in one direction than in the opposite direction.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element; the body assembly comprises a substantially cylindrical core segment and at least one flange segment; the flange segment is integral with, or attached at least to one point adjacent to, an end of the core segment; the flange segment extending radially outward from the center longitudinal axis of the core segment. The flow control element attaches to at least one point along the core segment and the flow control element provides greater resistance to flow in one direction than another direction.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element. The body assembly comprises a substantially cylindrical core segment and at least one flange segment integral with, or attached to at least one end of, the core segment; the flange segment extending radially outward from the axis of the core segment. The flow control element attaches to at least one point along the core segment and the flow control element is at least partially open to flow when there is no pressure differential across the flow control element.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element. The body assembly comprises a substantially cylindrical core segment and at least one flange segment integral with, or attached to at least one end of, the core segment and extending away from the axis of the core segment. The flow control element attaches to at least one point along the flange assembly and provides greater resistance to flow in one direction than the other direction.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element. The body assembly comprises a substantially cylindrical core segment and at least one flange segment integral with, or attached to at least one end of, the core segment and extending away from the axis of the core segment. The flow control element attaches to at least one point along the flange assembly and is at least partially open to flow when there is no pressure differential across the flow control element.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element. The body assembly comprises a substantially cylindrical core segment and at least one flange segment integral with, or attached to at least one end of, the core segment and extending away from the axis of the core segment. The flow control element extends at least partly onto the flange assembly and creates a sealable contact to the atrial septum and provides greater resistance to flow in one direction than the other direction.
• In embodiments, the interatrial pressure vent comprises a body assembly and a flow control element. The body assembly comprises a substantially cylindrical core segment and at least one flange segment integral with, or attached to, at least one end of the core segment and extends away from the axis of the core segment. The flow control element attaches to the flange assembly and creates a sealable connection to the atrial septum and is at least partially open to flow when there is no pressure differential across the flow control element.
• In embodiments, the interatrial pressure vent comprises a body assembly with a first end and a second end and a flow control element; the body assembly comprises a core segment including at least one flange segment integral with, or attached to, at least one point adjacent to the first end of the core segment and at least one other flange segment integral with, or attached to, at least one point adjacent to the second end of the core segment; the flange segments extending radially outward from the center longitudinal axis of the core segment and the flange segments oriented so they do not oppose each other when deployed. The flow control element attaches to at least one point along the core segment and the flow control element provides greater resistance to flow in one direction than it does in another direction.
• In embodiments, the interatrial pressure vent comprises a body assembly with a first end and a second end and a flow control element; the body assembly comprises a core segment including at least one flange segment integral with, or attached to, at least one point adjacent to the first end of the core segment and at least one other flange segment integral with, or attached to, at least one point adjacent to the second end of the core segment; the flange segments extending radially outward from the center longitudinal axis of the core segment and the flange segments oriented so they do not oppose each other when deployed. The flow control element attaches to at least one point along the core segment and the flow control element is at least partially open to flow when there is no pressure differential across the flow control element.
• In embodiments, the interatrial pressure vent comprises a body assembly with a first end and a second end and a flow control element comprised of at least one leaflet; the body assembly comprises a substantially cylindrical core segment and a number of flange segments integral with, or attached to, at least one point on each side of the body segment and extending radially outward from the center longitudinal axis of the core segment; the number of flange segments on either side of the core segment being a whole multiple of the number of leaflets.
• In embodiments, the interatrial pressure vent comprises a body assembly with a first end and a second end and a flow control element comprised of at least one leaflet; the body assembly comprises a substantially cylindrical core segment and a number of flange segments integral with, or attached to, at least one point on each side of the body segment and extending radially outward from the center longitudinal axis of the core segment; the number of flange segments being a whole multiple of the number of leaflets. The flow control element attaches to at least one point of the body assembly and the flow control element provides greater resistance to flow in one direction than another direction.
• In embodiments, the interatrial pressure vent comprises a body assembly with a first end and a second end and a flow control element comprised of at least one leaflet; the body assembly comprises a substantially cylindrical core segment and a number of flange segments integral with, or attached to, at least one point on each side of the body segment and extending radially outward from the center longitudinal axis of the core segment; the number of flange segments being some multiple of the number of leaflets. The flow control element attaches to at least one point of the body assembly and is at least partially open to flow when there is no pressure differential across the flow control element.
• In embodiments, an implant system comprises an interatrial pressure vent and placement catheter for treating heart failure. The implant system is comprised of a body assembly and a flow control element. The body assembly is comprised of a substantially cylindrical core segment and at least one flange segment integral with, or attached to, at least one end of the core segment and extending radially away from the core segment. The flow control element is attached to at least one point along the core segment and provides greater resistance to flow in one direction than the other direction. The placement catheter is comprised of an inner shaft and an outer shaft. The inner shaft comprises an elongate tube and a handle component. The inner shaft also contains at least one lumen that extends along at least part of the length of the inner shaft. The outer shaft comprises an elongate hollow tube or sheath and a different handle component that slideably interfaces with the first handle component.
• In embodiments, an implant system comprises and interatrial pressure vent and placement catheter for treating heart failure. The implant system is comprised of a body assembly and a flow control element. The body assembly is comprised of a substantially cylindrical core segment and at least one flange segment integral with, or attached to, at least one end of the body assembly and extending radially away from the body segment. The flow control element is attached to at least one point along a flange and provides greater resistance to flow in one direction than the other direction. The placement catheter is comprised of an inner shaft and an outer shaft. The inner shaft comprises an elongate tube and a handle component. The inner shaft also contains at least one lumen that extends along at least part of the length of the inner shaft. The outer shaft comprises an elongate hollow tube (or sheath) and a different handle component that slideably interfaces with the first handle component.
• In embodiments, an implant system comprises and interatrial pressure vent and placement catheter for treating heart failure. The implant system is comprised of a body assembly and a flow control element. The body assembly is comprised of a substantially cylindrical core segment and at least one flange segment integral with, or attached to, at least one end of the body assembly and extending radially away from the body segment. The flow control element is attached to at least one point along a flange and provides greater resistance to flow in one direction than the other direction. The placement catheter is comprised of an inner shaft and an outer shaft. The inner shaft comprises an elongate tube with at least one flange or circumferential groove formed in the outer diameter and a handle component. The inner shaft also contains at least one lumen that extends along at least part of the length of the inner shaft. The outer shaft comprises an elongate hollow tube (or sheath) and a different handle component that slideably interfaces with the first handle component.
• In other embodiments, an embodiment comprises a device for treating a heart condition in a patient comprising a body element having a core segment defining a passage, a first annular flange comprising a plurality of flange segments, and a second annular flange comprising a plurality of flange segments. In embodiments, at least a portion of one of the flange segments is either more or less flexible than the remaining portion of the flange segment or other portions of the body element, including but not limited to the cylindrical core segment. In one embodiment, the first annular flange is less flexible than the second flange, which is more flexible than the first annular flange.
• In other embodiments, the device comprises a third or intermediate annular flange for better adherence to the septal wall.
• In other embodiments, the device comprises a flow control element configured to aim the flow of blood in a desired direction. In other embodiments, the device is configured to be more easily retrieved during deployment. Such embodiments can include among other elements a at least one extended flange segment in one of the annular flanges that is able to be retained within a placement catheter when the other portions of the device are deployed.
• In embodiments, the method of placing the interatrial pressure vent into position may comprise a sequence of steps to locate and gain access to a vascular channel leading to the heart, placing an introducer catheter via this channel into one of the atriums of the heart, locating the interatrial septum between the left and right atriums, creating an opening in the interatrial septum, advancing a placement catheter containing an interatrial pressure vent into one of the atriums and then through the opening created in the interatrial septum between the right and left atriums, and then controllably deploying the interatrial pressure vent so it is securably connected to the interatrial septum.
• Deployment of the interatrial pressure vent preferably occurs in a series of steps comprising first advancing the placement catheter through the septal opening, second deploying a first flange, third retracting the placement catheter to position the first flange against the septal wall, and fourth deploying a second flange on the other side of the septal wall from the first flange.
• In embodiments where the device disclosed herein is implanted into the atrial septum, the introducer catheter may be placed through the inferior vena cava via a femoral vein to the right atrium.
• Other pathways are available including placing the introducer catheter through the superior vena cava via a jugular vein; through the aorta, via a femoral artery, past the aortic valve and into the left atrium; through the aorta, via a brachial artery, past the aortic valve and into the left atrium; through the superior vena cava via a basilica vein; through the superior vena cava via a cephalic vein; intraoperatively, through an opening created in the right atrium either for this reason or during a procedure performed for some other purpose; intraoperatively through an opening created in the left atrium either for this reason or during a procedure performed for some other reason; or via a guidewire that is positioned through the interatrial septum and located in the pulmonary artery.
• Regarding the placement catheter, in some embodiments the placement catheter is designed to function as the introducer catheter and the placement catheter, eliminating the need for a catheter exchange. While in other embodiments, the introducer catheter, the placement catheter, or both are constructed to be exchanged over only part of their length to avoid the necessity of handling a guidewire that is at least twice as long as the catheter. Still in other embodiments, the introducer catheter or the placement catheter, or both has a pre-shaped curve to enable orientation of the placement catheter substantially orthogonal to the septal wall. The catheter may be curved between 30° and 45° away from the catheter axis at a point between 5 and 15 centimeters away from the distal end of the placement catheter.
• In embodiments where the inventive device is to be placed in the atrial septum, an opening in the septum can be performed using the introducer catheter in a separate procedure from the interatrial pressure vent placement procedure. Access through the opening can be maintained via a wireguide positioned in the right atrium or the pulmonary artery. The opening can be formed using the placement catheter via a distal tip segment that is part of the placement catheter.
• The opening may be predilated using a balloon or other dilating device either as part of the procedure described or as a separate procedure.
• In another aspect, the opening is formed and dilated as part of a single, unified procedure with the interatrial pressure vent placement procedure. This may be accomplished by integrating a balloon or other dilating component as part of the placement catheter and dilating the opening as part of placing the interatrial pressure vent. For example, this could be accomplished using a balloon that can be folded to achieve a small loaded profile and will have a suitable pressure capacity and suitable durability to dilate the septum opening and the interatrial pressure vent together.
• The opening that is formed in the interatrial septum may be formed by pushing a catheter tip through the septum at the location of septum primum. Because this septum is normally very thin, the distal tip may be pushed directly through without significant force.
• In an alternate method, the opening in the interatrial septum can be formed with a cutting tool that is advanced through the introducer catheter or the placement catheter. The tool preferably comprises a blade and a shaft. The blade contains at least two surfaces and one edge. The edge is sharpened and formed at an angle so that the blade slices as it is advanced into and through the septum.
• In yet another method, the opening in the interatrial septum can be formed with a cutting tool that is advanced through the introducer catheter or the placement catheter. The tool preferably comprises a blade and a shaft. The blade contains at least two surfaces and two separate edges that are sharpened at an angle so that the blade slices as it is advanced into and through the septum and the septum is cut generally in an x shaped opening.
• In yet another method, the opening in the interatrial septum can be formed with a punching tool that is advanced through the introducer catheter or the placement catheter. The punching tool preferably comprises a cutting assembly and a shaft. The cutting assembly preferably comprises a hollow, conical shape with a sharpened edge along the base circumference. The cutting assembly is connected at least to one point on the shaft and is generally oriented so the apex of the cone is pointed away from the shaft.
• In one method, the cutting assembly can be operated by advancing the conical assembly through the interatrial septum and then pulling it back to form an opening that is generally circular. In another method, the cutting assembly can be operated by advancing the conical assembly through the interatrial septum and then rotating it as it is pulled pack to create a circular cutting action against the interatrial septum.
• In another embodiment, the cutting tool can be formed of at least one cutting member and one shaft. The cutting member is connected at least to one point along the shaft and the other end of the cutting member is adjustably positioned so it can lie alongside the shaft or at some angle away from the shaft. To place the cutting tool, the cutting member is placed alongside the shaft and then advanced through the septum. Then the cutting member would be adjusted to a second position, radially further away from the shaft than the first position, and the shaft would be positioned so the cutting member exerts lateral stress against the septum. The cutting member could be designed to slice the septum in this manner. In another method, the cutting tool could be rotated once the shaft and cutting member were repositioned so the slicing motion would cut a generally circular hole through the septum.
• In embodiments, the cutting member is round wire. In another embodiment, the cutting member can be connected to one output of a power supply, capable of supplying a suitable signal to the cutting member, the other output of which is connected to a ground plate placed against the patient's skin. An appropriate electric potential can be placed between the cutting member and ground plate to cause a concentrated current density near the wire to aid in cutting through the septum tissue.
• In another embodiment, the cutting member is a section of tubing sliced lengthwise and appropriately formed to create a cutting edge. During placement, the cutting member is controllably positioned to lie against the shaft as the shaft is advanced through the placement catheter and through the opening created in the interatrial septum. Once positioned, the placement catheter is retracted and the shaft is positioned within the septum. Once positioned in this manner, the cutting member can be controllably adjusted to a second position, radially further away from the shaft than the first position, and the shaft positioned so the cutting member exerts lateral stress against the septum.
• In yet another method, an opening is created in the interatrial septum which is smaller than the diameter of the outer surface of the body of the interatrial pressure vent according to the present disclosure such that, when the interatrial pressure vent is initially deployed within the interatrial septum, there is some compression from the septum against the body of the interatrial pressure vent.
• Referring now to the placement catheter used to position and controllably place the interatrial pressure vent; in one aspect, the placement catheter consists of an inner member and an outer member.
• In embodiments, the outer member is comprised of a tubing member and a first handle component, the outer shaft is less than about16 F in diameter and formed of a material suitably smooth and resilient in order to restrain the stowed interatrial pressure vent and allow smooth stowing and deployment, such as PTFE, FEP, modified ETFE fluoropolymer (such as Tefzel®), PVDF, HDPE or other suitable materials.
• In embodiments, the inner member is comprised of at least one tubing member with an inner lumen through at least part of the tubing member, and a second handle component attached to the proximal end, with the second handle component slideably attached to the first handle component.
• In embodiments, the handle components are interconnected via an inclined, helical lever to enable advancement of the inner member relative to the outer member by rotating the outer shaft handle while holding the inner shaft handle.
• In embodiments, the handle components comprise a locking mechanism that prevents the handle component from moving in relationship to each other beyond a certain predetermined length.
• In embodiments, the handle components contain at least two locking mechanisms that prevents the handle component from moving in relationship to each other beyond two different predetermined length.
• In embodiments, the inner member contains a stiffening element adjacent to the distal area.
• In embodiments, a system for treating heart failure in a patient consists of an interatrial pressure vent and placement device. The interatrial pressure vent comprises a body section and a flow control element. The body section comprises a core section and at least one flange segment. The flange segment comprises a midsection adjacent to the body and an end section that has a greater wall thickness than the midsection. The placement device comprises an inner shaft and an outer shaft. The inner shaft comprises an outside diameter and an internal lumen extending at least partly toward the proximal end from the distal end.
• The outer shaft contains an outside diameter and an inside diameter. The inner shaft contains a necked portion or circumferential groove along at least part of its length of smaller diameter than at least a portion of the inner member distal to the necked portion; the space formed between the outside of the necked portion and the inside of the outer shaft being sufficient to contain a folded or otherwise compressed interatrial pressure vent of the present disclosure and the space formed between the outside of the non-necked portion and the inside of the outer shaft being insufficient to contain the interatrial pressure vent.
• In embodiments, a system for treating heart failure in a patient consists of an interatrial pressure vent and placement device. The interatrial pressure vent comprises a body section and a flow control element. The body section comprises a core section and at least one flange segment. The flange segment comprises a midsection adjacent to the body and an end section located radially further away than the midsection and with a larger dimension in the radial direction than the midsection. The placement device comprises an inner shaft and an outer shaft. The inner shaft contains an outside diameter and an internal lumen extending at least partly toward the proximal end from the distal end. The outer shaft contains an outside diameter and an inside diameter. The inner shaft contains a first necked portion or circumferential groove comprising a length and a diameter; the diameter of the first necked portion of the inner shaft being smaller than at least a portion of the inner member distal to the necked portion and the inner shaft also containing a second necked portion, proximal to the first necked portion and of a length sufficient for containing end section of the flange segment and a diameter smaller than the first necked portion; the space formed between the outside of the first necked portion and the inside of the outer shaft being sufficient to contain the folded or otherwise compressed interatrial pressure vent of the present disclosure except for the end section of the flange segment; the space formed between the outside of the non-necked portion and the inside of the outer shaft being insufficient to contain the interatrial pressure vent and the space formed between the outside of the second necked portion and the inside of the outer shaft being sufficient to contain the end section of the flange segment.
• In another aspect, the inner member comprises a first necked portion along at least part of its length of smaller diameter than at least a portion of the inner member distal to the first necked portion and second necked portion, along a second part of its length proximal to the first necked portion and smaller than the first necked portion. The space between the outside of the necked portion and the inside of the outer sheath.
• Referring now to the body assembly of the interatrial pressure vent, in one aspect, the body comprises a core segment and at least one flange segment. In embodiments, the body assembly comprises a core segment; a first flange comprising at least one flange segment at one end of the core segment; and a second flange comprising at least one flange segment at the opposite end from the first flange of the core segment.
• In embodiments, the body assembly comprises a core segment, comprising a self expanding mesh; a first flange, at one end of the core segment; and a second flange at the opposite end of the core segment from the first flange.
• In embodiments, the body assembly is comprised of a core segment, comprising a balloon expandable mesh; a first flange at one end of the core segment; and a second flange at the opposite end of the core segment from the first flange.
• In embodiments, the body assembly is comprised of a core segment; a first flange at one end of the core segment; and a second flange at the opposite end of the core segment from the first flange; each flange oriented to extend substantially radially outward relative to the center axis the flange segment.
• In embodiments, the body assembly is comprised of a core segment; a first flange at one end of the core segment; and a second flange at the opposite end of the core segment from the first flange; each flange oriented to extend substantially radially outward from the core segment; and at least one flange extending beyond 90° relative to the center axis of the core segment.
• In embodiments, the body assembly is comprised of a core segment; a first flange at one end of the core segment; and a second flange at the opposite end from the first flange of the core segment; each flange oriented to extend substantially radially outward from the core segment; the first flange formed with a smaller radius of curvature than the second flange.
• In embodiments the interatrial pressure vent comprises a flow control element biased to allow flow from one atrium of a patient to the other atrium of the patient with lower resistance than in the reverse direction.
• In embodiments the interatrial pressure vent comprises a flow control element biased that remains at least partially open when there is no pressure differential across the vent.
• In embodiments, the interatrial pressure vent comprises an integral filter to prevent embolic particles larger than about2mm from passing beyond the filter in the direction of flow.
• In other embodiments, the interatrial pressure vent comprises a tubular flow element which extends a distance beyond the core segment so as to prevent embolic particles from entering the left atrium.
• In embodiments, the interatrial pressure vent comprises at least one movable flap that responds to pressure changes between the right and left atrium.
• In embodiments, the body assembly may be constructed from preformed wire braid. The wire braid may be formed from nitinol with a martensite/austenite transition temperature is below 37° C. so it remains in its superelastic, austenitic phase during use. The transition temperature is below about 25+/−5° C. The wire should have a diameter of at least about 0.0035 (about 2 lbs of breaking strength at 200 ksi tensile). The wire should have a very smooth surface to reduce thrombogenicity or irritation response from the tissue. The surface finish may be 63 μin RA or better. This surface may be obtained either by mechanical polishing, by electropolishing or a combination. In embodiments, the surface may be cleaned with detergents, acids and/or solvents to remove residual oils or contamination and then controllably passivated to insure minimal corrosion.
• In embodiments, the body assembly may be formed fromgrade 1 titanium. In embodiments, the body may be formed of grade 6 titanium. In embodiments, the body may be formed of grade 9 titanium. In embodiments, the body may be formed of 316L stainless steel. In embodiments, the body may be formed of 416L stainless steel. In embodiments, the body may be formed of nitinol or cobalt-chromium-nickel alloy (such as Elgiloy®). In embodiments, the body is formed of platinum iridium. In embodiments, the body may be formed of a cobalt chromium alloy. In embodiments, the body may be formed of MP35N®. In embodiments, the body may be formed of Vitalium™. In embodiments, the body may be formed of Ticonium™. In embodiments, the body may be formed of Stellite®. In embodiments, the body may be formed of tantalum. In embodiments, the body may be formed of platinum. Materials disclosed with reference to the body or any component of the device disclosed herein are not meant to be limiting. The skilled artisan will appreciate that other suitable materials may be used for the body or any other component of the device.
• In embodiments, the body assembly is preferably formed from a length of cylindrical tubing that is precut with slots at specific locations and then formed in a series of processes to produce a shape suited for the purpose of containing a flow control element within the interatrial septum.
• As an example, a first process might be to stretch the cylinder to expand its internal diameter to a uniform target dimension. This can be done with a balloon or a standard tubing expander consisting of a segmented sleeve and tapered conical inserts that increase the diameter of the sleeve when the cones are advanced toward the center. In order that the shape of the stretched tubing be preserved, the cylinder should be annealed while held into this stretched shape by heating it beyond 300° to 600° for at least about 20 minutes to allow the internal stresses to be relieved. A second process might be to form one flange end shape using a similar process as the first process but using a tool shape specially designed for the first flange shape. A third process might be to form the second flange end shape using a similar process as the first process but using a tool specially designed for the third flange shape. These shapes must be annealed using a similar process as the first shape, either in separate steps or altogether.
• In embodiments, the internal diameter of the finished interatrial pressure vent is larger than about 5 mm to enable adequate venting of the left atrium and minimize damage to blood components from excessive shear stress, but enabling the interatrial pressure vent to stow in a placement catheter of smaller than about 14F.
• In embodiments, the flow control element opening is at least about 50 sq. mm. In embodiments, the flow control element opening is 50 sq. mm. +−10 sq. mm. In another embodiment, the cylindrical section is formed with an inside diameter of between 3 and 15 mm.
• The internal diameter of the body segment is preferably a constant dimension along the center, longitudinal axis of the interatrial pressure vent and is long enough to isolate the flow control element from deflection or damage as a result of contact with other structural elements of the heart.
• In embodiments, the body segment is formed into a substantially toroidal shape, the inner diameter tapering down and then up again from one side of the implant to the other. In embodiments, the length of the body section may be about 4 mm. In embodiments, the length of the body section may be between about 3 mm and about 40 mm.
• In yet other embodiments, the flange segment may comprise at least a single loop which is oriented to the cylindrical shape by at least about 90° relative to the central axis of the cylinder and projected outward to a distance away from the center axis of greater than the opening in the atrial septum but at least about 3 mm further than the diameter of the inner cylinder.
• In embodiments, the flange segment is formed of multiple struts that extend radially outward, with respect to the center aspect of the cylinder. In embodiments, the flange struts each comprise a substantially triangular shape that is wider adjacent to the body section than at the outer edge of the strut. In embodiments, the flange struts comprise a substantially triangular shape that is wider adjacent to the body section than at the outer edge of the strut and contains an integral hole at the outer edge for containing a radiopaque marker.
• In embodiments, the flange segments comprise a substantially triangular shape that is wider adjacent to the body section than at the outer edge of the segment and whose outer edge is rounded to reduce trauma against the tissue it contacts. In embodiments, the flange segments are formed from a single beam of material that projects outward from the center longitudinal axis of the body section. In embodiments, the flange segment is formed of spiral shaped flange struts that are coplanar and substantially orthogonal to the central axis of the cylinder.
• In embodiments, the flange segment is formed of at least one looping member that attaches to at least one portion of the body section. In embodiments, the flange is preferably formed to automatically recover substantially to its preformed shape following partial deployment of the interatrial pressure vent from the placement catheter. In this manner, the interatrial pressure vent will resist being pulled back through the septal opening.
• In embodiments, the flow control element device may be a tissue valve, a synthetic valve or a combination. The flow control element can be formed from animal or human tissue, such as bovine pericardial tissue. The procedures for obtaining these tissues and preparing them for use as implanted valve components are well known to those skilled in the art. The flow control element could be a trileaflet valve, or also a bileaflet valve, or also a simple flap valve. The flow control element could also be a ball and socket valve, a duckbill valve, a butterfly valve, or any other valve component known to those skilled in the art.
• In embodiments, the flow control element can be biased by adding a separate component that is attached to at least one point along the body or flange segment and contacts against at least one point of the flow control element surface at least at some point during its duty cycle. The component can be preformed to controllably affect the flow control element behavior. For example, in one embodiment, the flange segment can be a looped wire formed from nitinol and connected to the body section and cantilevered against the surface of the flow control element facing the left atrium and formed so that the surface of the flow control element is biased to be slightly open when the pressure is equal in the left atrium and right atrium. Biasing can also be accomplished by varying the stiffness of the material of the valve or components thereof.
• In embodiments, a flange segment could be formed out of a helical winding of nitinol, with a core wire to connect one end of the flange segment to the other end. In embodiments, the flow control element can be preshaped to resist moving against pressure in one direction. In embodiments, the flow control element could be biased to remain open at a predetermined pressure, or at a neutral pressure.
• In embodiments, the interatrial pressure vent consists of a body section and a flow control element; the body section comprising a cylindrical core segment and two flanged end sections; the flow control element being sealably secured to at least three points along the body section; the flanged end sections each comprising at least one flange segment that extends radially outward from the body section; the flow control element comprising at least one movable element that allows fluid passage in one direction with lower resistance than another direction. In embodiments, the body section is elliptical in shape, or cylindriod and designed to offset asymmetric stress created by a linear septal opening.
• In embodiments, the formed metal flange segments consist of at least two flange segments, with at least one on each side of the septum. In embodiments, the flange segments are positioned so they do not pinch the septum between them, thereby reducing possible pressure necrosis. In embodiments, the flange segments are shaped so the wall thickness perpendicular to the septum is less than the wall thickness parallel to the septum, thereby increasing flexibility without decreasing strength.
• In embodiments, the flange segments are formed so the radius of curvature at the end is greater than about 0.03 inches. In embodiments, there is a radiopaque marker, preferably tantalum or platinum alloy, formed around, or integral with, the flange segment end to increase radiopacity and increase the area of contact between the flange segment and septum. In embodiments, the flange on the left atrium side of the septum is bent at a shorter radius of curvature than the right atrium side.
• In embodiments, the flange on one side of the interatrial septum is formed to return to greater than a 90° angle relative to the axis of the center cylinder. In embodiments, holes are preformed at a location along the cylindrical section for suture sites for securing the valving device.
• The above summary of the disclosure is not meant to be exhaustive. Other variations and embodiments will become apparent from the description and/or accompanying figures disclosed herein and below. The embodiments described above employ elements of each other and are meant to be combined with each other. For example, embodiments of flow control element may be used with differing configurations of the body element, flange, or segment thereof. While certain combinations are disclosed, the invention is not so limited.
• Other embodiments and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying figures. Understanding that these figures merely depict exemplary embodiments, they are, therefore, not to be considered limiting. It will be readily appreciated that the components of the present disclosure, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Nonetheless, embodiments will be described and explained with additional specificity and detail through the use of the accompanying figures in which:
• FIG. 1 is a schematic cross-sectional view of a patient's heart with an interatrial pressure vent in situ;
• FIG. 2 is an end view of the interatrial pressure vent ofFIG. 1 in situ as seen along line2-2 ofFIG. 1;
• FIG. 2A is an end-on close up view of a flange segment of an embodiment;
• FIG. 2B is an enlarged side cross-sectional view of an embodiment to illustrate variations in flexibility in a flange;
• FIG. 3 is a cross-sectional side view taken along line3-3 ofFIG. 2;
• FIG. 4 is perspective view of the body assembly of the interatrial pressure vent by itself;
• FIG. 5 is a right side view of the body assembly ofFIG. 4;
• FIG. 6 is a distal end view of the body assembly ofFIG. 4;
• FIG. 7 is an enlarged fragmentary cross-sectional view taken along line7-7 ofFIG. 6;
• FIGS. 7A through 7C are a side elevational views of embodiments of the device in the stowed position;
• FIG. 8 is a side elevational view of the interatrial pressure vent ofFIG. 1 in a collapsed configuration prior to loading in a placement catheter;
• FIG. 9 is a side view of the distal end of a placement catheter in its open position;
• FIG. 10 is a side view of the distal end of a placement catheter in its open position and with an interatrial pressure vent in its stowed configuration and in position over the inner shaft of the catheter;
• FIG. 11 is a side view of the distal end of a placement catheter in a closed configuration with an interatrial pressure vent in its stowed configuration loaded onto the placement catheter;
• FIG. 11A is a side view of another embodiment of a placement catheter with an interatrial pressure vent stowed therein;
• FIG. 12 is an exploded perspective view of the proximal and distal ends of a placement catheter;
• FIG. 13 is a cutaway view of a heart of a patient and the distal end of a placement catheter in position across the interatrial septum;
• FIG. 14 is a schematic cross sectional side view of the proximal and distal end of a placement catheter in a closed position and positioned across the interatrial septum of the heart of a patient;
• FIG. 15 is a view similar toFIG. 14 but showing the distal end of the placement catheter in a partially open position and the distal flange segments of the interatrial pressure vent deployed;
• FIG. 16 is a view similar toFIG. 15 but showing the distal flange segments of the interatrial pressure vent in position against the wall of the interatrial septum;
• FIG. 17 is an enlarged cross-sectional detail view of the distal end of the placement catheter ofFIG. 16 but showing the distal flange segments of the interatrial pressure vent being retracted from the interatrial septum as if it were determined to be in an undesirable position by imaging the radiopaque markers and going to be redeployed;
• FIG. 18 is a view similar toFIG. 16 but showing further deployment of the interatrial pressure vent by releasing the proximal flange segments if imaging determines a correct positioning of the distal flange segments;
• FIG. 19 is an enlarged cross-sectional detail view of the placement catheter ofFIG. 18 but showing the interatrial pressure vent fully released in position and the placement catheter being removed;
• FIG. 19A is schematic depiction of another embodiment of a placement catheter system and interatrial pressure device along with the deployment process therefor;
• FIG. 19B is schematic depiction of another embodiment of a placement catheter system and deployment process therefor;
• FIG. 20 is a side elevational view of an alternate embodiment of an interatrial pressure vent body with slanted flange segment ends;
• FIG. 21 is a side elevational view of an alternate embodiment of an interatrial pressure vent body with staggered flange segment ends;
• FIG. 22 is a perspective view of an alternate embodiment of an interatrial pressure vent body with an integrated retrieval means and thrombus clot strain;
• FIG. 23 is a right side view of the body assembly ofFIG. 22;
• FIG. 24 is an end view of an alternate embodiment of interatrial pressure vent;
• FIG. 25 is a cross-sectional side view taken along line25-25 ofFIG. 24;
• FIG. 26 shows and alternate embodiment wherein thecore segment106 is ovular rather than circular and thus the core segment is a cylindroid or elliptic cylinder rather than a simple cylinder;
• FIG. 27 is schematic depiction of another embodiment of a placement catheter system and interatrial pressure device along with the deployment process therefor;
• FIG. 27A is a side elevational view of the embodiment described in connection withFIG. 27 in the stowed position;
• FIGS. 28A through 28C depict other embodiments of the device that direct the flow of blood in a desired direction;
• FIG. 29 is an end-on view from the RA side of embodiments of exit profiles of the flow control element;
• FIG. 30 is a side view of an embodiment of the device having a tube-like extension into the RA side of the heart;
• FIG. 31 depicts an exploded view of a first embodiment of a mounting and loading tool for mounting and loading a prosthesis;
• FIG. 32 depicts an exploded view of a second embodiment of a mounting tool for mounting a prosthesis;
• FIGS. 33 and 34 depict the mounting tool with a prosthesis mounted;
• FIG. 35 depicts an exploded view of a loading tool for loading a prosthesis on a mounting tool onto a delivery device;
• FIG. 36 depicts the prosthesis being loaded into a catheter;
• FIG. 37 depicts the loaded catheter with protective packaging;
• FIGS. 38A and 38B depict an additional embodiment of a control device or handle for deploying the prosthesis;
• FIGS. 39A and 39B depict another embodiment of a control device for deploying the prosthesis;
• FIG. 40 depicts another embodiment of a control device or handle;
• FIG. 41 depicts a retrieval device useful for retrieving a deployed prosthesis;
• FIG. 42 depicts the retrieval device ofFIG. 41 with a retrieval basket deployed;
• FIG. 43 depicts a closer view of the basket ofFIG. 42;
• FIGS. 44 and 45 depict retrieval devices using dilators; and
• FIGS. 46-49 depict additional embodiments of an implantable prosthesis with retrieval and redeployment features.
• FIG. 50 depicts anatomy of a human being and a human heart, with particular focus on the pathways and natural lumens of the body;
• FIG. 51 depicts a closer view of a heart and how guide wires and catheters may be maneuvered in and around the heart to deploy embodiments;
• FIG. 52 depicts a first catheter extending from the superior vena cava to the coronary sinus of the heart;
• FIG. 53 depicts an ablative catheter in the coronary sinus for creating an opening into the left atrium of the heart;
• FIG. 54 depicts the ablative catheter creating the opening;
• FIG. 55 depicts a balloon catheter for expanding the opening;
• FIG. 56 depicts a coronary sinus pressure relief stent in a non-deployed state;
• FIG. 57 depicts the stent ofFIG. 56 in a deployed state;
• FIG. 58 depicts a first embodiment of a flange for the atrial wall;
• FIG. 59 depicts a second embodiment of a flange for the atrial wall;
• FIG. 60 depicts another embodiment of a stent suitable for ensuring communication between the right atrium and the coronary sinus;
• FIG. 61 depicts details of a stent with a one-way valve; and
• FIGS. 62A and 62B depict another embodiment of a stent.
DETAILED DESCRIPTION
• Certain specific details are set forth in the following description and Figures to provide an understanding of various embodiments. Those of ordinary skill in the relevant art will understand that they can practice other embodiments without one or more of the details described below. Finally, while various processes are described with reference to steps and sequences in the following disclosure the steps and sequences of steps should not be taken as required to practice all embodiments of the present disclosure.
• As used herein, the terms “subject” and “patient” refer to any animal, such as a mammal like livestock, pets, and preferably a human. Specific examples of “subjects” and “patients” include, but are not limited, to individuals requiring medical assistance, and in particular, requiring treatment for symptoms of heart failure.
• As used herein, the term “pressure differential” means the difference in pressure between two points or selected spaces; for example between one side of a flow control element and another side of the flow control element.
• As used herein, the term “embolic particle” means any solid, semi-solid, or undissolved material, that can be carried by the blood and cause disruption to blood flow when impacted in small blood vessels, including thrombi.
• As used herein, the terms “radially outward” and “radially away” means any direction which is not parallel with the central axis. For example, considering a cylinder, a radial outward member could be a piece of wire or a loop of wire that is attached or otherwise operatively coupled to the cylinder that is oriented at some angle greater than 0 relative to the center longitudinal axis of the cylinder.
• As used herein, the term “axial thickness” means the thickness along an axis parallel to the center longitudinal axis of a shape or component.
• As used herein, the term “axial direction” means direction parallel to the center longitudinal axis of a shape or component.
• As used herein, a “sealable connection” is an area where components and/or objects meet wherein the connection defines provides for an insubstantial leakage of fluid or blood through the subject area.
• As used herein, the term “lumen” means a canal, duct, generally tubular space or cavity in the body of a subject, including veins, arteries, blood vessels, capillaries, intestines, and the like.
• As used herein, the term “sealably secured” or “sealably connected” means stably interfaced in a manner that is substantially resistant to movement and provides resistance to the flow of fluid through or around the interface.
• As used herein, the term “whole multiple” means the product contains no decimal.
• The present disclosure provides structures that enable several unique intracardiac and intraluminal valve devices, loaders, controls and placement devices and catheters therefor. In some embodiments directed toward the intra-cardiac setting, these valve devices are intended to allow sufficient flow from the left atrium to the right atrium to relieve elevated left atrial pressure and resulting patient symptoms but also prevent the amount of flow from the right atrium to the left atrium to minimize the potential for thrombi or other embolic material from entering the arterial circulation.
• However, it should be appreciated that embodiments are applicable for use in other parts of the anatomy or for other indications. For instance, a device such as that described in this disclosure could be placed between the coronary sinus and the left atrium for the same indication. Also, a pressure vent such as is described in this disclosure could be placed between the azygous vein and the pulmonary vein for the same indication.
• Referring now toFIG. 1, one embodiment is used as an interatrial pressure vent.FIG. 1 depicts the heart of a human subject. “LA” refers to the left atrium, and “RA” refers to the right atrium. The interatrial septum is depicted as107.Interatrial pressure vent100 includes abody element101 andflow control element104, embodiments of which will be described in further detail below. Thebody element101 comprisesflanges102 and103. In this and other embodiments described herein,flanges102 and103 may be annular flanges, which define agap2000 into which theseptum107 fits. In embodiments, after insertion, the interatrial pressure vent is securely situated in an opening created in the interatrial septum. Arrow F inFIG. 1 shows the direction of flow. It can be thus seen that a build up of pressure in the LA can be vented, by way of the inventive device, to the RA.
• Referring now toFIG. 2, an embodiment of the interatrial pressure vent is illustrated.Interatrial pressure vent100 includesbody element101 comprising a substantially open mesh and including a substantially cylindrical core segment (shown end on)106 and substantiallyannular flanges102 and103.Flanges102 and103 may be comprised of any number of flange segments (or “flange elements” or “flange members”)102a-102hand103a-103h, that are attached adjacent to the end of the core segment and extend radially outward from longitudinal axis of the core segment and flowcontrol element104. “Flange segments” may also be referred to as “legs” herein. Theflanges102 and103 (and thus the segments which comprise them102a-hand103a-h) in this and all embodiments disclosed herein, may also be integral with the core segment. That is, they need not be necessarily “attached” thereto but may be fabricated from the same material that defines the core segment (including in the manners described above and herein) and thus may be contiguous therewith. The flow control element may be attached to the body element, for example atlocations105. The flange segments in this and any embodiment of any annular flange may be formed of two individual strut elements or also can be formed of a single element. The flange segments may be generally rectangular in cross section, circular in cross section, oval in cross section or some other geometric shape.
• In embodiments, the flange segments are designed to be more flexible than the core segment. In such embodiments, the increased flexibility may be achieved in several ways. In embodiments, a dimension of the surface of the strut elements that make up the flange segments is altered relative to the corresponding dimension of the struts (or elements, or members) that make up the core segments.FIG. 2A illustrates such embodiments.FIG. 2A shows anexample flange segment103aviewed end on. As shown, the end-facing dimension of strut element of103xhas a width D. By decreasing the width D in relation to the width of the outward-facing dimension of the struts that comprise the core segment, an increased flexibility of the flanges in relation to the core segment or other flange members (or portions thereof) can be achieved.FIG. 2B shows an enlarged fragmentary cross-section of an embodiment of the device substantially shown inFIG. 6. The view is taken along line7-7 ofFIG. 6. In this figure, the cross hatched area shows the area of increased flexibility. It can be seen that one area of the flange segment is thus more flexible than another area. In embodiments where the strut elements are circular, then in a similar fashion, the diameter of the strut element could be made to have a diameters less than the diameter of the strut (or similar elements) comprising the mesh-like configuration of the core segment.
• In embodiments where the flange element is made from a different section of material and is attached to the core segment, the segment material could be chosen to have a greater flexibility than the core segment (or remaining portion of the flange segment or flange itself as the case may be). The choice of materials based on their flexibility will be apparent to those skilled in the art. In the ways described above, the flange segments can achieve greater flexibility than the core segment (or the remaining portion of the flange segment or the flange itself as the case may be) thereby reducing probability of damage to the tissue of the septum while allowing the core segment to maintain a strong outward force against the septal opening and thus decrease the probability that the device could become dislodged.
• In embodiments having an open-mesh configuration for thebody element101, the body element can be formed from a number of materials suitable for use in a patient, such as titanium, nitinol, stainless steel, Elgiloy®, MP35N®, Vitalium, Mobilium, Ticonium, Platinore, Stellite®, tantalum, platinum, or other resilient material. Alternatively, in such embodiments, thebody element101 can be formed from a polymer such as PTFE, UHMWPE, HDPE, polypropylene, polysulfone, or other biocompatible plastic. The surface finish of the body element may be smooth with no edges or sharp discontinuities. In other embodiments, the surface finish is textured to induce tissue response and tissue in growth for improved stabilization. In embodiments, the open mesh ofbody element101 can be fabricated from a resorbable polymer such as polylactic acid, polyglycolic acid, polycaprolactone, a combination of two or more of these or a variety of other resorbable polymers that are well known to those skilled in the art.
• In embodiments, the structure of the body element may be uniform and monolithic.
• In other embodiments, the body element (mesh or monolithic) comprises porous materials to encourage tissue ingrowth or to act as a reservoir for containing one or more compounds that will be released over time after implant to address numerous issues associated with the product performance. These compounds can be used to diminish calcification, protein deposition, thrombus formation, or a combination of some or all of these conditions. The compound can also be used to stimulate an irritation response to induce tissue ingrowth. In embodiments, the compound can be an anti-inflammatory agent to discourage tissue proliferation adjacent to the device. Numerous agents are available for all of such uses and are familiar to those who are skilled in the art.
• In embodiments, the material that comprises the body may be multilayered comprising a coating of resorbable polymer or semipermeable polymer that may comprise various compounds that may be released, and in some embodiments in a controlled manner over time, after implant to address numerous issues associated with product performance.
• The mesh can be formed from wire that is pre-bent into the desired shape and then bonded together to connect the component elements either by welding them or adhesively bonding them. They could be welded using a resistance welding technique or an arc welding technique, preferably while in an inert gas environment and with cooling control to control the grain structure in and around the weld site. These joints can be conditioned after the welding procedure to reduce grain size using coining or upset forging to optimize fatigue performance.
• In other embodiments, the mesh can be formed from a hollow tube that has been slotted using, for example, a machining laser or water drill or other method and then expanded to form the open structure. If a sufficiently elastic and resilient material, such as nitinol, is used, the structure can be preformed into the finished shape and then elastically deformed and stowed during delivery so the shape will be elastically recovered after deployment. The surface of the finished assembly must be carefully prepared to insure is passivated and free of surface imperfections that could be a nidus for thrombus formation.
• In embodiments, theflow control element104 is a tissue valve such as a tricuspid valve, a bicuspid valve or a single flap valve formed from pericardial tissue from a bovine, porcine, ovine or other animal. Any number of cusps may be used. The flow control element is formed using a number of processing steps and auxiliary materials such as are well known in the art.
• Theflow control element104 can also be a ball valve, a duckbill valve, a leaflet valve, a flap valve, a disc in cage type valve, a ball in cage type valve or other type of valve formed from a polymer or polymers or a combination of polymers, ceramics and metals such as Dacron (polyester), PTFE (such as Teflon®), polyurethane, PET or other suitable polymer; titanium, stainless steel, nitinol, MP35N®, cobalt-chromium-nickel alloy (such as Elgiloy®), or other suitable metal; zirconia, silicone nitride, or other suitable ceramic. Valves or portions thereof may comprise different stiffness/flexibly properties with respect to other valves or portions thereof in the flow control element.
• Theflow control element104 preferably extends to a point along theflange assembly103 to enable creation of a sealable connection to the septum wall after placement. This is more particularly shown inFIG. 3 where it can be seen that in embodiments, the flow control element extends beyond the length of the core segment and is folded and attached to the core segment so as to create a lip that extends in a direction center of the opening in the vent. When the device is abutted against the septal wall, this lip forms said sealable connection and thus can reduce the likelihood that blood can flow through the septal opening via pathways between the outer surface (septal-facing surface) of the interatrial pressure venting device and the septal opening. Theflow control element104 is attached to thebody element101. This can be accomplished by using a suture material, such as silk, nylon, polypropylene, polyester, polybutylester or other materials such as are well known to those skilled in the art. In embodiments,flow control element104 can be attached tobody element101 using adhesive bonding agents such as cyanoacrylate, polymethylmethacrylate, or other materials such as are well known to those skilled in the art. In other embodiments,flow control element104 can be attached tobody element101 via staples, rivets, rings, clamps or other similar methods as are well known to those skilled in the art.
• As mentioned above, flow control element can be made of material selected for its flexibility/stiffness. In embodiments where a loose valve is desired that resonates more closely with the cycle of the heart, a however stiffness material may be chosen. In embodiments where it is desired to open the valve when the pressure differential reaches a selected value, the material of the flow control element can be selected and/or processed in a manner to open at the desired differential. The leaflets or sections of the flow control element itself may also comprise areas of variable stiffness, and or may be more flexible or less flexible than other leaflets or components of the flow control element.
• FIG. 3 shows the device implanted in the atrial septum of the heart of a patient. As can be seen from the figure, thecore segment106 can be formed contiguously withflanges102 and103 and thusflange segments102a-102hand103a-103hrespectively. In the embodiment shown,flow control element104 is contained within thecore segment106 so it does not extend beyond the face of thebody element101, thereby insulating it from contact from other body structures or peripheral tissue. in embodiments, thecore segment106 can be extended to protrude beyond theinteratrial septum107 and theflange assembly102 and/or103 on at least one side of theinteratrial septum107 and can be formed with a shape that extends to create a lip in the manner described above. In embodiments, the ends of theflange assemblies102,103 are formed to lie at a parallel angle to and against the septal wall along at least a part of its length to increase the area of contact and thereby decrease the stress concentration against the septal wall.
• Referring now toFIG. 4, an embodiment of the body element is shown. This perspective view of thebody element101 shows how, in embodiments, the ends offlange segments102a-102h,103a-103hare rounded at theirdistal ends115 and116 to reduce stress concentrations against the interatrial septum after placement. This rounded shape can easily be formed as part of the integral shape of the flange segment. In other embodiments, the thickness of the segment in this area may be decreased to decrease the stress further against the interatrial septum, which is similar to embodiments described above. Also similar to embodiments described above, if the segment is round, the diameter can be decreased in order to increase flexibility. Also, as described above a different material of higher flexibility could be used for the end portions of the segments.
• While rounded shapes at the ends of the flange segments reduce stress on the septum, other variations on this theme are contemplated.FIGS. 7A through 7C illustrate embodiments where the shape of the end portions of the flange segments has configurations to achieve less stress against the septal wall—among other goals.FIG. 7A is a side elevational view of embodiment of the pressure venting device in its stowed configuration.Core segment106 ofbody element101 is shown and, in this embodiment, is integral withflanges103 and102. The individual flange segments are not labeled; however, it is easily seen thatflange103 comprises segments substantial similar to those described above. There is no eyelet or opening at the end of the segment in the embodiment shown.Flange102 shows an embodiment where the flange segment is not comprised of a triangular or multi-strut arrangement as described above but rather a single-member segment. Any flange may be constructed with single-member segment. An example single member is referred to as103s. In this example, at the end of each single-member flange segment (102s) for example, there is an eyelet.FIG. 7B shows an embodiment similar to that shown inFIG. 7A where the end of thesegments102sare not eyelets but rather pads.FIG. 7C shows another embodiment where the ends of thesegments102 are paddle shaped. Other smooth-edged shapes could be used, and it should be understood that such shapes and configurations apply to all manner of flange segment ends, not only single-member segments. This would include the ends of flange segments shown and described herein, for example with reference toFIGS. 2 through 7.
• FIGS. 7A-C also show embodiments having at least one flange segment being longer than the other flange segments. Again, while represented as single-member flange segments they need not be and as such a configuration with at least one longer segment may apply to any flange-segment configuration disclosed herein. The benefits and purpose of having at least one longer flange segment will be described more fully below.
• In embodiments, the outer ends of theflange segments102a-102h,103a-103hare formed with integral marker holes orslots109 and110 (shown inFIGS. 3 and 7 for example) in whichmarkers118 and119 can be positioned so the device may more easily be visualized using radiographic imaging equipment such as with x-ray, magnetic resonance, ultrasound or other imaging techniques. Markers as disclosed herein may be applied to the ends of any segments, not just those with holes or eyelets therein. Aradiopaque marker118 and119 can be swaged, riveted, or otherwise placed and secured in the hole and thereby dimensioned to be flush with the end of the segment. Markers may also be simply attached or to end of a segment not having a hole. In all embodiments having markers, flange ends115 and116 are more visible when imaged. In other embodiments, themarkers118 and119 can be bonded with an adhesive agent such as cyanoacrylate or epoxy or a variety of other materials that are available and suitable for implant as are well known. The markers may be proud (as shown for example inFIG. 7) or flush with the end of the flange segment. Theradiopaque markers118 and119 may be formed of tantalum, tungsten, platinum iridium, gold, alloys of these materials or other materials that are known to those skilled in the art. Alsomarkers118 and119 comprising cobalt, fluorine or numerous other paramagnetic materials or other echogenic materials that are known to those skilled in the arts can be incorporated together with the radiopaque materials, or in alternating locations of the flange segments to enable both x-ray and echographic imaging of the interatrial pressure vent. Alternatively, the ends of theflange elements102a-102hand103a-103hcan be wrapped with a foil made of the same marker materials. In embodiments, the radiopaque material can be laminated to the flange segments and bonded through a welding process or using an adhesive such as cyanoacrylate or numerous other adhesives known to those skilled in the art.
• Suture rings117 can be formed in the body element to locate and fix the attachment site along the body element to the flow control element. The suture rings can be circular holes formed into the structure or they could also be some other shape such as rectangular or triangular and also can be formed as a secondary step, for example by standard machining techniques, using a secondary laser machining step, or with electro-chemical etching. Preferably the connection between a segment and any other segment of the body element are formed with as large a radius as possible to increase resistance to fatigue failure. Also, preferably, all edges of the formed device are rounded to improve biocompatibility and hemocompatibility.
• The pattern of suture rings as well as which of the rings are selected during suturing may affect the properties of the flow control element. For example, in embodiments where it is desired to have the flow element loose and flappable, less suture rings may be utilized and, in such embodiments, RA-side end of the flow control element may contain relatively less sutures than the LA side. In other embodiments, it may be desirable to keep the flow control element affixed to the core segment for a increased length of the segment thereby reducing the amount of flow control element material that affecting flow. Still in other embodiments the top or bottom portion the flow element at the RA side may be sutured in such a way so as to allow the top or bottom portion of the flow control element to affect flow more than the other portion respectively. Embodiments discussed below where the flow is “aimed” may utilize suturing patterns effective to enable the desired flow control element configuration.
• Returning to the flange segments, in an embodiment, theinteratrial pressure vent100 is comprised of an equal number of flange segments on each side of the interatrial septum. In embodiments, there are eight flange segments on each side of the core segment. In another aspect there are an equal number of suture rings and flange segments on one side of the interatrial pressure vent. In other embodiments, there are seven flange segments on each side of the core segment. In other embodiments, there are six flange segments on each side of the core segment. In other embodiments, there are five flange segments on each side of the core segment. In other embodiments there are four flange segments on each side of the core segment. In other embodiments there are three flanges on each side of the core segment. In other embodiments there are two flanges on each side of the core segment. In other embodiments, there is one flange on each side of the core segment. Still in other embodiments there are more flange segments as compared to flange segments. And in other embodiments, there are more flange segments as compared to flange segments. As can be seen there are a number of variations for the number of flange segments and the skilled artisan will appreciate that any number could be used while not deviating from the scope and spirit of this disclosure.
• Referring now toFIG. 5, the body element of an embodiment is displayed in side view. The flange segments can be formed to produce a gap G (also referred to as an annular gap) between the ends of flange segments on one side of the body and flange segments on the other side of the body, when the device is in its “native” or un-deployed state. When the device is deployed, it flexes to accommodate the tissue and as such the gap may expand when tissue is positioned therein. In embodiments, this gap is slightly smaller than the thickness of the interatrial septum. In other embodiments, the gap can be larger than the thickness of the interatrial septum. In other embodiments the gap can be zero. In another aspect the gap can be negative: in this case the flange segments on each side of the body can be formed to cross each other in order to exert more pressure between the deployed flange segments and the interatrial septum. Also shown inFIG. 5 areradiopaque markers118 and119, which in embodiments are shown to be located adjacent to the end of the flange segments.
• Referring now to the embodiment shown inFIG. 6, theflange segments102a-102hare oriented so they are not directly opposed toflange segments103a-103hon the opposite side of the body element so that after placement there is no pinching points thereby reducing the chance for tissue injury. In embodiments,flange segments102a-102hare arranged midway between adjacent ends offlange segments103a-103h. In embodiments the length offlange segments102a-102hare similar to the length offlange segments103a-103h. However in other embodiments the length offlange segments102a-102hare identical to the length offlange segments103a-103h;the length offlange segments102a-102hare longer than103a-103h;and the length offlange segments102a-102hare shorter thanflange segments103a-103h.
• Referring now toFIG. 7, in embodiments having radiopaque markers it can be seen that theradiopaque markers118 and119 may be placed into the marker holes109 and110 (or placed on the ends of flange segments that do not have holes) to locate the ends of theflange segments102a-102hand103a-103hwith a non-invasive imaging technique such as with x-ray or echosound during or after the procedure. In embodiments, themarkers118 and119 can be formed to be flush in an axial direction with the outer surface and the inner surface of theflange segments102a-102hand103a-103h. In another aspect, themarkers118 and119 can be formed to extend in an axial direction beyond the outer surface of theflange segments102a-102hand103a-103h, away from the interatrial septum. In embodiments, themarkers118 and119 can be formed to extend in an axial direction beyond the inside of theflange segments102a-102hand103a-103h, toward the interatrial septum. In embodiments, themarkers118 and119 can be formed to extend in an axial direction beyond the inside and the outside of theflange segments102a-102hand103a-103h. In embodiments, themarkers118 and119 can be formed to be recessed in an axial direction within the surface of the inside of theflange segments102a-102hand103a-103h. In embodiments, themarkers118 and119 can be formed to be recessed in an axial direction within the outside of theflange segments102a-102hand103a-103h. In embodiments, themarkers118 and119 can be formed to be recessed in an axial direction within both the inside and the outside of theflange segments102a-102hand103a-103h. In embodiments, themarkers118 and119 can be formed to extend in a radial direction within the width of theflange segments102a-102hand103a-103h. In embodiments, themarkers118 and119 can be formed to extend in a radial direction flush with the width of theflange segments102a-102hand103a-103h.
• Referring now toFIG. 8, aninteratrial pressure vent100 is shown in its stowed configuration. In embodiments, the interatrial pressure vent can be collapsed to a substantially cylindrical shape for stowing in a delivery catheter during placement.Flange segments102a-102hand103a-103hcan be fabricated to be substantially equal in length. The “stowed position” is not meant to apply only to devices having flange segments of equal length but rather to all embodiments of the venting device disclosed herein. Devices having flange segments of varying length and orientation such as those described herein are also designed to stow in substantially the same manner as shown inFIG. 8. In anembodiment200 seen inFIG. 20, flange segments202a-202hand203a-203hare formed on a slanted angle so that, when marker elements are secured to the ends of the flange segments, the flange segments can be stowed into a smaller volume. Inembodiments300 seen inFIG. 21, flange segments302a-302hare formed of alternating length to allow stowage into a smaller volume.
• Referring now toFIG. 9, an embodiment of the distal end of theplacement catheter111 is shown in its open position. Theinner shaft112 is fabricated with acenter lumen136 of sufficient diameter to contain aguidewire138 or also for use in injecting contrast or other liquid. Commonly, the lumen would be sized for a guidewire of 0.010″, 0.011″, 0.014″, 0.018″, 0.021″, 0.028″, 0.035″, 0.038″, 0.042″ or 0.045″. Thislumen136 can also be used to measure pressure at the distal end of the catheter using other equipment and techniques that are well known to those skilled in the art. Thelumen136 preferably extends through the entire length of theinner shaft112. Alternatively, theguidewire lumen136 can extend for a shorter length in the proximal direction and then through a side hole (not shown) of the inner sheath. A corresponding side hole (not shown) is placed on theouter shaft113 adjacent to the side hole in theinner shaft112 to create a pathway between thecenter lumen136 of theinner shaft112 and the outside of theouter shaft113. In this way it is possible to pass a guidewire from this distal end of theinner lumen136 through the side hole and exchange the catheter over a guidewire that is less then twice the length of thecatheter111 while securing the guidewire position during exchange.
• In embodiments, theinner shaft112 is configured with awaist section120 to contain the foldedinteratrial pressure vent100 between the gap formed in the space outside of this section ofinner shaft112 and the inside of theouter shaft113. Theinner shaft112 may be formed to contain at least onecircumferential groove114 at the proximal end ofwaist section120 that forms a recess between the inside of theouter shaft113 and the smallest diameter of the groove that is greater than the gap formed in the space between thewaist section120 and the inside of theouter shaft113.Radiopaque markers118 can extend in a radial direction past the outer surface of theflange segments102a-102hand in embodiments, when interatrial pressure vents are folded into their stowed configuration and placed into position overinner shaft112,radiopaque markers118 are dimensioned to fit intogroove114. Other similarly dimensioned sections may be used; that is, that which fits into the groove need not necessarily be a radiopaque marker. In embodiments, when interatrial pressure vents are stowed in this manner, the gap betweenwaist section120 and the inside ofouter shaft113 is not sufficient to allowradiopaque markers118 beyond the distal end ofgroove114 unless theouter sheath113 is retracted beyond the proximal end ofgroove114.
• Theinner shaft112 may be formed with agroove121 on the distal end of thewaist section120 adjacent to the location of the distal end of the interatrial pressure vents are radiopaque markers119 (or similar dimensioned members) can extend in a radial direction past the outer surface of theflange segments102a-102hand in embodiments, when interatrial pressure vents are folded into its stowed configuration and placed into position overinner shaft112,radiopaque markers119 are dimensioned to fit intogroove121. In another aspect, theinner shaft112 may be formed with acircumferential groove114 on the proximal end ofwaist section120 and acircumferential groove121 on the distal end of thewaist section120 The inner shaft can be formed of a variety of polymers or metals or combinations of polymers and metals that are suitable for use in a patient. The inner shaft can be fabricated from a single length of PTFE, UHMWPE, FEP, HDPE, LDPE, polypropylene, acetal, Delrin, nylon, Pebax, other thermoplastic rubber, aliphatic or aromatic polyurethane, or a variety of other engineering resins that are well known to those skilled in the art. In embodiments, the inner shaft can be fabricated using multiple layers of two or three of the above-mentioned polymers to combine desirable properties of each. For example, the outer surface could be composed of polyurethane to enable easier bonding of auxiliary components to the inner shaft. The inner layer could be PTFE to convey better lubricity to the inner shaft. In embodiments, the inner shaft and or the outer shaft could be coated on the inner and or outer surface with a coating material that conveys specific properties to the shaft like antithrombogenicity or lubricity. There are numerous available coating materials suitable for these purposes as are well known to those skilled in the art. The inner shaft can be compounded with a radiopacifier to increase the visibility of the inner shaft under fluoroscopy using bismuth salts such as bismuth subcarbonate, bismuth oxychloride, bismuth trioxide, tungsten powder, molybdenum powder or other radiopacifier such as are well known to those skilled in the arts. Similarly, the outer sheath can be fabricated from the same set of materials as the inner sheath, in the same manner and using the same coatings. Embodiments described below in connection with a flange rather than circumferential groove operate in substantially the same manner as described above and herein, except the device does not necessarily have projections that fit into and are retained by the grooves.
• Referring now toFIG. 10, a folded representativeinteratrial pressure vent100 is shown in its stowed position with theplacement catheter111 shown in its open position. In practice, if the body of the interatrial pressure vent is fabricated of nitinol or other elastic material, when the placement catheter is in its fully open position, theflange segments102a-102hand103a-103hwould automatically recover into a shape like that shown in, for example,FIG. 4, hence this Figure is shown to illustrate the position of theinteratrial pressure vent100 relative to thewaist section120 andgrooves114 and121. When radiopaque markers (or similarly dimensioned members)118 extend beyond the thickness of the inside ofbody segment101 ofinteratrial pressure vent100, they form a projection withininteratrial pressure vent100 that can be captured withingroove114 to secure the position of theinteratrial pressure vent100 during placement. During deployment, theouter shaft113 ofplacement catheter111 is retracted a sufficient distance to reveal the distal portion of theinteratrial pressure vent100 allowing theflange segments103a-103hto dilate radially away from the central longitudinal axis ofbody101. By capturing the radiopaque118 markers within thegroove114, the device can be repositioned easily without further deployment, or the device can be completely retracted and removed from the patient without deployment as indicated inFIG. 17.
• Referring now toFIG. 11, aninteratrial pressure vent100 is shown completely stowed within theplacement catheter111.
• FIG. 11A shows an embodiment of the placement catheter similar in operation to those described herein but operative to engage an interatrial pressure vent by way of a slightly different mechanism than described above in connection with circumferential grooves. This figure shows a schematic depiction of a stowed interatrial vent. Rather than having the grooves as described above, this embodiment of a placement catheter comprises an inner shaft having a flange or member3000 (rather than a groove) which has a diameter larger than that of the inner shaft to grip and hold an end of the interatrial vent device as shown. As shown in the figure, the flange and its segments (collectively referred to in the figure as102) wrap around the ball-shapedflange3000 and allow the interatrial pressure vent to be moved with the placement device in the manners described herein.
• Referring now toFIG. 12, aplacement catheter111 is shown. It should be noted that while the inner shaft is depicted as having grooves inFIG. 12, the inner shaft may comprise theflange3000 as described above in connection withFIG. 11A. The skilled artisan will appreciate that the operation of the device is substantially similar whether grooves or flanges are utilized. Theplacement catheter111 comprises a first handle component128 that can be attached toouter shaft113. The first handle component can be attached to theouter shaft113 using a variety of adhesive methods such as solvent bonding using a solvent for both the handle and outer shaft material; an organosol consisting of a solvent and polymer in solution that is compatible with both the outer shaft and the first handle component; a polymerizable adhesive, such as polyurethane, cyanocrylate, epoxy or a variety of other adhesives as are well known to those skilled in the art. The first handle component can be fabricated from a variety of metals such as aluminum, stainless steel, titanium or a number of other metals and alloys as are well known to those skilled in the art. In embodiments, the first handle component128 is fabricated from a polymer such as polycarbonate, or a variety of engineering resins, such as Lexan®, or others as are well known to those skilled in the art.
• The first handle component compriseshand grip section124 andtubular shaft section125. Thetubular shaft section125 can contain keyway122 that is formed or machined into the shaft section. The keyway is preferably formed with three linear sections; a first linear section131, a second linear section132 and a third linear section133. Each of these sections is formed to traverse along a path primarily parallel with the center axis along the length of the first handle component but each is displaced radially from one another by at least about half of the width of the keyway. Theplacement catheter111 also can comprise a second handle component129 that can be attached toinner sheath112. The second handle component can be fabricated from the same variety of metals and polymers as the first handle component. The two handles can be fabricated from the same materials or from different materials. The second handle component can be attached to the inner sheath in the same manner and using the same materials as the first handle component attaches to the outer sheath. In embodiments, the second handle component can contain threaded hole126 for containing set screw127. The set screw can be twisted to capture the inner shaft against the second handle component. The second handle component129 also can comprise a secondhand grip section134 and secondtubular shaft section130. The second tubular shaft section can contain key123 that is formed or machined of suitable dimension to adapt to keyway122 of first handle component128. When assembled, second handle component129 can be slideably moved relative to first handle component128 in a manner controlled by the shape and length of the key way122. As the second handle129 is advanced relative to the first handle128, it can be appreciated that heinner sheath112 will slide in a distal direction out from theouter sheath113. It can be appreciated that when the second handle component129 is assembled, the key123 is slid into the first linear section131 and advanced until it hits the edge of the keyway formed between the first linear section131 and the second linear section132. In order for the second handle component129 to advance further, it must be rotated and, once rotated, it can be advanced further but will stop when the key123 hits the edge of the keyway formed between the second linear section132 and the third linear section133. The keyway dimensions are preferably selected with consideration for the combination of lengths of other components in the placement device.
• A first position, defined as the position when the key123 is in contact with the proximal edge formed between the first linear section131 and the second linear section132, is preferably determined so, when fully assembled and with the interatrial vent in its stowed position within the placement catheter, theouter shaft113 will completely cover the length of theinteratrial pressure vent100 as is desired during catheter placement. The keyway dimensions can also be selected to result in a second position, defined as the position when the key123 is in contact with the distal edge formed between the second linear section132 and third linear section133. The second position would preferably be selected to reveal the full length offlange segments103a-103hbut retainflange segments102a-102hwithin theouter shaft113 of the catheter. The length of the third linear section133 would preferably be selected so that, when the second handle component129 was advanced completely against the first handle component128, the full length of theinteratrial vent100 would be uncovered by theouter shaft113 and the device would be deployed. A variety of other configurations of the first and second handle components could be used for this same purpose. The first handle componenttubular shaft section125 and the second handle componenttubular shaft section130 could be threaded (not shown) so the first handle component128 could be screwed into the second handle component129. Alternatively, gear teeth (not shown) could be formed in the firsttubular shaft section125 of the first handle component128 and a gear wheel (not shown) could be incorporated into the secondshaft tubular section130 of the second handle component129. The gear wheel would preferably be chosen to mesh with the gear teeth and the second handle component129 could be advanced toward the first handle component128 by rotating the gear wheel. A variety of other design configurations could be utilized to control the relative location between the first handle component and the second handle component as are well known to those skilled in the art.
• FIGS. 13 through 17 show embodiments of a system for treating heart failure. More specificallyFIGS. 12 through 19 show how the placement catheter is introduced and positioned in a patient and methods for placing the interatrial valve in a patient. Theinteratrial pressure vent100 is presterilized and packaged separately from theplacement catheter111. Sterilization can be performed by exposing the device to a sterilizing gas, such as ethylene oxide, by exposing the device to elevated temperature for an adequate period of time, by using ionizing radiation, such as gamma rays or electron beam or by immersing the device in a fluid that chemically crosslinks organic molecules, such as formaldehyde or glutaraldehyde and then rinsed in sterile water or sterile saline. For each of these sterilization methods, consideration must be given to compatibility of the materials so device performance is not adversely affected as a result of the sterilization process. Also, the packaging design and materials must be carefully considered with the sterilization procedure, post sterilization handling and storage, environmental exposure during storage and shipment, and ease of handling, opening, presentation and use during the procedure.
• In embodiments,interatrial pressure vent100 can be assembled using components that have been pre-sterilized using one of the above methods or others that are well known and the final assembly may be accomplished in an aseptic manner to avoid contamination.
• In embodiments, theinteratrial pressure vent100 can be supplied non-sterile and be sterilized around the time of use using one of the above methods or by other methods well known by those skilled in the art.
• Similarly, theplacement catheter111 may be pre-sterilized and packaged separately from theinteratrial pressure vent100. Sterilization can be performed using a similar method to theinteratrial pressure vent100 or using a different method from the same choices or using some other method as is well known by those skilled in the art.
• In embodiments, aninteratrial pressure vent100 and theplacement catheter111 can be supplied pre-sterile and in the same package. In another aspect, theinteratrial pressure vent100 and theplacement catheter111 can be preloaded and supplied pre-sterile.
• Prior to insertion, theinteratrial pressure vent100 is preferably folded and stowed onto theplacement catheter111. This can be accomplished in a sterile field and using aseptic techniques in the following steps. First theinteratrial pressure vent100 is presented to the sterile field and theplacement catheter111 is presented to the sterile field. Second, theinteratrial pressure vent100 andplacement catheter111 are inspected for visible signs of damage, deterioration or contamination. Third, the second handle component129 of theplacement catheter111 is retracted fully so theouter shaft113 exposes theinner shaft112 to the maximum extent allowed. Fourth, theinteratrial pressure vent100 is positioned in the correct orientation over theinner shaft113 of theplacement catheter111 with theinner shaft113 oriented through the center of theflow control element104. Fifth, theflange segments102a-hand103a-hare folded away from each other and theflange segments102a-hand103a-h l and thecore segment106 are compressed radially to fold theinteratrial pressure vent100 into a size and shape that will fit over and onto thewaist section120 of theinner shaft112 with the distal ends115 offlange segments102a-haligning with theproximal groove114 ofinner shaft112.
• In embodiments comprising a flange as described inFIG. 11A theflange segments102a-hand103a-hare folded away from each other and theflange segments102a-hand103a-hand thecore segment106 are compressed radially to fold theinteratrial pressure vent100 into a size and shape that will fit over theflange3000 described onFIG. 11A. This folding may be accomplished with the aid of an insertion tool (not shown) that retains theinteratrial pressure vent100 in a stowed position oninner shaft112 and then advancingouter shaft113 over the stowedinteratrial pressure vent100 and displacing the insertion tool, thereby leaving theouter shaft113 completely covering theinteratrial pressure vent100 and mating with the distal taperedtip140 of theinner shaft112. In other embodiments, this can be accomplished by hand using the fingers of one hand to hold the distal ends115 of theflange segments102a-102hin position atgroove114 of theinner shaft112 and advancing theouter shaft113 over theinner shaft112 enough to hold theflange segments102a-102hin place. Completion of the loading procedure is accomplished by progressively advancing theouter shaft113 until it completely covers theinteratrial pressure vent100 as shown inFIGS. 11 and 11A. While the below discussion regarding placement of the interatrial pressure vent uses the placement device shown inFIGS. 9-11 as an example, the description on placement and the procedure therefore is also meant to apply to embodiments where the inner shaft comprises a flange rather than grooves.
• Positioning of the loadedinteratrial valve100 andplacement catheter111 in preparation for implanting theinteratrial valve100 in the patient can be accomplished by: first gaining vascular access; second, positioning aguidewire121 in the right atrium of the patient; third, positioning an introducer (not shown) into the patients right atrium; fourth, locating the interatrial septum; fifth, advancing the introducer through the interatrial septum and into the patient's left atrium; sixth, advancing theguidewire138 into the left atrium; seventh, refracting the introducer; eighth, advancing the loadedplacement catheter111 andinteratrial pressure vent100 into position so the distal end and approximately half of the stowed length of theinteratrial pressure vent100 is protruding through the interatrial septum and into the patient's left atrium as shown inFIG. 13.
• In embodiments, positioning of the loadedinteratrial valve100 andplacement catheter111 in preparation for implanting theinteratrial valve100 in the patient can be accomplished by: first gaining vascular access; second, positioning aguidewire138 in the right atrium of the patient; third, advancing the loadedinteratrial valve100 andplacement catheter111 overguidewire138 by inserting the guidewire into and throughlumen136 and advancingplacement catheter111 into the patient's right atrium; fourth, locating the interatrial septum; fifth, advancing theplacement catheter111 through the interatrial septum and into the patient's left atrium so the distal end and approximately half of the stowed length of theinteratrial pressure vent100 is protruding through the interatrial septum and into the patient's left atrium as shown inFIG. 13.
• Implanting interatrial pressure vent100 into a patient can be accomplished, once the loaded interatrial pressure vent100 and placement catheter111 are in position as shown inFIG. 14, by first, retracting first handle component128 toward second handle component129 while holding second handle component129 until flange segments103a-hare fully uncovered as shown inFIG. 15, and as can be verified by visualizing the markers119 using fluoroscopy or using echocardiography; second, retracting the placement catheter111 with partially deployed interatrial pressure vent100 toward the patient's right atrium until the flange segments103a-hare in contact with the left atrial side of the interatrial septum, as shown inFIG. 16, and as can be verified using the same techniques mentioned or as can be perceived by the user based on the resistance felt against further proximal movement of the placement catheter111; fourth, continuing to retract the outer sheath113 by retracting second handle129 until the outer sheath113 is retracted beyond the proximal end of groove114 of inner shaft112 and also uncovers flange segments102a-h,at which time the flange segments102a-hof interatrial pressure vent100 will deploy returning to the preloaded geometry and capture the interatrial septum between the flange segments103a-hand flange segments102a-has shown in shown inFIG. 18; fifth, the inner sheath is retracted through the flow control element104 of interatrial pressure vent100, into the patients right atrium as shown inFIG. 19; fifth the second handle component129 is advanced toward the first handle component128 to reposition inner shaft112 into the position relative to outer shaft113 it was in during placement and the placement catheter is removed from the patient and the procedure is completed.
• In other embodiments, implanting interatrial pressure vent100 into a patient can be accomplished, once the loaded interatrial pressure vent100 and placement catheter111 are in position as shown inFIG. 14, by first, advancing second handle component129 toward first handle component130 while holding first handle component128 until flange segments103a-h are fully uncovered as shown inFIG. 15, and as can be verified by visualizing the markers119 using fluoroscopy or using echocardiography; second, refracting the placement catheter111 with partially deployed interatrial pressure vent100 toward the patient's right atrium until the flange segments103a-hare in contact with the left atrial side of the interatrial septum, as shown inFIG. 16, and as can be verified using the same techniques mentioned or as can be perceived by the user based on the resistance felt against further proximal movement of the placement catheter111; fourth, continuing to retract the outer sheath113 by retracting second handle129 until the outer sheath113 is retracted beyond the proximal end of groove114 of inner shaft112 and also uncovers flange segments102a-h,at which time the flange segments102a-hof interatrial pressure vent100 will deploy returning to the preloaded geometry and capture the interatrial septum between the flange segments103a-hand flange segments102a-has shown in shown inFIG. 18; fifth, the inner sheath is retracted through the flow control element104 of interatrial pressure vent100, into the patients right atrium as shown inFIG. 19; fifth the second handle component129 is advanced toward the first handle component128 to reposition inner shaft112 into the position relative to outer shaft113 it was in during placement and the placement catheter is removed from the patient and the procedure is completed.
• For a variety of reasons, it may be necessary or desirable to removeinteratrial pressure vent100 andplacement catheter111 during any part of the procedure without further risk or injury to the patient. This is possible as follows: if, for any reason, it is desired for the device to be removed beforeouter shaft113 is retracted andflange segments103a-h are deployed, then theplacement catheter111 withinteratrial valve100 can simply be refracted out through the same pathway as introduced.
• If, following deployment offlange segments103a-hit is necessary or desirable to remove the device, then theinteratrial valve100 can be retracted into theplacement catheter111 by advancing first handle128 away from second handle129, while holding second handle129 stationary, thereby advancingouter sheath113 distally through the interatrial septum and over theflange segments103a-h.In embodiments,radiopaque markers118 placed in marker holes109 are captured in groove114 (seeFIG. 17) and cannot fit in the gap betweenwaist120 ofinner shaft112 and inner surface ofouter shaft113, so asouter sheath113 is advanced,flange segments103a-hare forced to fold inward toward their stowed position and are retracted back ontoinner shaft112 and withinouter sheath113. Onceouter shaft113 is fully advanced,catheter111 can be refracted as shown inFIG. 17 to be removed out through the interatrial septum and out through the same pathway as introduced.
• FIG. 19A is an embodiment designed to enhance the retrievability of the device. The procedure for implanting the device is substantially similar to that which is described above; however, there are variations to the placement catheter and the device, which will be described below. As discussed in connection withFIGS. 7A through 7C, embodiments of the interatrial venting device comprise at least one flange segment being longer than the other flange segments. The embodiment schematically shown inFIG. 19A preferably works with such embodiments having at least one flange segment that are longer in relation to the other flange segments; thus the segments shown in the RA have the same reference number as the longer segments inFIGS. 7A through 7C, i.e.,102L. In embodiments utilizing the techniques shown inFIG. 19A, the opening113aofouter sheath113 of placement catheter is angled or has a more surface area on one side relative to the other. The placement catheter is oriented during the procedure such that the angled opening (or the plane of the opening itself) is at an angle more normal to theseptal wall107. In the embodiment shown inFIG. 19A, that angle appears to be around45 degrees with respect to theseptal wall107, but any angle which provides an more normal angle with respect to the septal wall may be used, and any opening which provides more surface area of theouter sheath113 on one side with respect to the other side may be used.Reference numerals4000 through4050 refer to steps in the process described below. The process is largely similar to that described above or with respect to any well-known placement catheter system and process, therefore only the applicable differences will be described. As can be seen atsteps4000 through4020, the placement catheter is positioned and the device is in the beginning stages of deployment. Atsteps4030 and4040, the as theouter sheath113 is retracted and on the RA side (or when the inner shaft is advanced while the outer sheath is on the RA side, which is not shown), the opening allows one of the longer flange segments102L to be deployed after other flange segments have been deployed and are thus in contact with theseptum107. The at least one longer flange segment102L is retained in the placement catheter system by way of theouter sheath113, the length of which extends further on one side than the other due to the opening and thus covers the longer segment102L while the other shorter segments have been deployed. In this way, the operator of the placement catheter can determine if the interatrial device is in the proper position. If not, the operator can still retrieve the device up until the last point prior to full deployment, i.e., when at least one of the longer flange segments (102L for example) is still retained in the placement catheter by theouter sheath113. If it is in proper position, the deployment may commence.
• Another deployment embodiment is now described in connection withFIG. 19B. This deployment embodiment may be used with any embodiment of the interatrial vent described herein.Reference numerals5000 through5050 refer to steps in the process described below. Atstep5000, the LA side of the device (generally referred to in this figure as100) is deployed on the LA side of the heart. Further deployment is shown atstep5010 and the outer sheath is refracted into the RA side of the heart, which allowsflow control element104 to exit the placement catheter. Placement catheter is equipped with a balloon, which is in fluid communication, for example, withlumen136 described above orguide wire138. The skilled artisan will appreciate other configurations in which a balloon catheter may be provided in the placement catheter system. Upon deployment of the LA side flange or shortly thereafter,balloon139 is inflated (shown in step5020). The inflation of the balloon optionally coupled with a pulling-back motion of theplacement catheter111 holds thedevice100 against the LA side of theseptal wall107 and thereby prevents thedevice100 from dislodging during deployment and/or moving in a direction away from the septal wall.Step5040 shows the full deployment of thedevice100 while theballoon139 is inflated. When satisfactory deployment is achieved, theballoon139 is deflated and the placement catheter system is removed (shown at step5050).
• Now referring toFIG. 20, aninteratrial pressure vent200 is shown. In embodiments, flange segments202a-hand203a-hcan be formed with graduating length to reduce interference between flange segments202a-hand203a-hduring handling, folding and loading. In embodiments,radiopaque markers218 and219 protrude into the inner cylindrical shape of the stowed position of the interatrial pressure vent and each flange segment202a-hand203a-hdiffer in length by at least the width of theradiopaque markers218 and219. In embodiments, each flange segment202a-hand203a-hdiffer in length by at least at least 1 mm. In embodiments, each flange segment202a-hand203a-hdiffer in length by at least 2% of the overall length ofinteratrial pressure vent200 in the position shown inFIG. 20.
• Now referring toFIG. 21, aninteratrial pressure vent300 is shown. In embodiments, flange segments302a-hand303a-hcan be formed with alternating length to reduce interference between flange segments202a-hand203a-hduring handling, folding and loading. In embodimentsradiopaque markers318 and319 protrude into the inner cylindrical shape of the stowed position of theinteratrial pressure vent300 and alternating flange segments302a, c, e,andgare longer than flange segments302b, d, fandh,and correspondingly, flange segments303b, d, fandhare longer thanflange segments303a, c, eandgby at least the width of the radiopaque marker. In embodiments, alternating flange segments302a, c, eandgare longer than flange segments302b, d, fandhand, correspondingly, flange segments303b, d, fandhare longer thanflange segments303a, c, eandgby at least 1 mm. In one aspect the alternating flange segments302a, c, eandgare longer than flange segments302b, d, fandhand, correspondingly, flange segments303b, d, fandgare longer thanflange segments303a, c, eandgby at least 2% of the overall length ofinteratrial pressure vent300 in the position shown inFIG. 21.
• Referring now toFIG. 22 andFIG. 23, thebody element401 of an interatrial pressure vent with integral thrombus filter andretrieval cone442 is shown. In embodiments,conical struts444 are affixed tobody element401 at attachment points446 and converge atapex450. In embodiments,conical struts444 comprise single beams of similar material to flangesegments402 and403 and can be attached to the body element or formed at the same time as the body element using techniques described in this specification, and are thus integral with the remainder of the device. In embodiments the space betweenadjacent struts444 is about 2 mm. In embodiments, the space betweenadjacent struts444 is about 4 mm. As can be appreciated,conical struts444 will protrude into the right atrium of the patient after implant and spaces between conical struts will function to block the passage of solid material larger than the space betweenadjacent struts444. This will provide the function of preventing emboli that are larger than the space between theadjacent struts444 from passing from the right atrium to the left atrium.
• Referring again toFIG. 22 andFIG. 23, in embodiments the shape of the conical struts444 is not straight. In embodiments the shape of the conical struts444 can be concave when viewed on end as depicted inFIG. 22. In embodiments the conical struts can be curved in a direction away from the chord formed between the apex450 and the attachment points446. In embodiments there can be ahole451 throughapex450 large enough to receive a retrieval snare (not shown). It can be appreciated thatconical struts444 and apex450 can be used to aid retrieval of the interatrial pressure vent from a patient at some time after the implant procedure using a method as follows: A catheter tube with an internal lumen at least as large asapex450 can be placed into the patients right atrium using standard techniques and imaging equipment. A retrieval snare can be fabricated from the proximal end of a guidewire bent sharply by about180 degrees and this snare can be inserted through the catheter tube and advanced into the patient's right atrium and with the assistance of fluoroscopy advanced throughhole451 or aroundconical struts444. Once the retrieval snare is engaged in this manner, it will be possible to retract the interatrial pressure vent by advancing a catheter tube while holding slight tension on the snare and thereby guide the catheter tube overapex450 and ontoconical struts444.
• As the catheter tube continues to advance, with some tension on the snare it will be possible to force the conical struts inward, thereby forcing theflange segments402 to begin folding inwards. When the conical struts are nearly completely in the catheter tube, the catheter tube can be held in a stationary position and the snare wire retracted against it, thereby causing the attachment points446 between theconical struts444 and theflange segment402 to be retracted into the catheter.Flange segments402 can begin to be retracted into the catheter at this point and the distal ends offlange segments402 can be diverted toward the patients left atrium but will also fold inward and into the catheter. Once theflange segments402 are inside of the catheter tube, the snare can be held stationary and the catheter tube can be advanced further, through the interatrial septum and overflange segments403. Once theflange segments403 are retracted into the catheter, the catheter and snare can be moved together to retract the interatrial pressure vent into the patient's right atrium and out through the pathway through which it was introduced.
• Referring now toFIGS. 24 and 25 an alternate embodiment ofinteratrial pressure vent500 is shown. In embodiments,flow control element504 is comprised of leaflets541a-c.Body element501 is comprised ofcore segment506 andflange segments502a-1 and503a-1 (not fully visible inFIG. 25); the number of flange segments being a multiple of the number of leaflets. This configuration improves the symmetry of strain against the flow control leaflets and also improves the uniformity of motion by the flow control element to changes in blood flow.
• In embodiments the number of leaflets comprising the flow control element is three and the number of flange segments on each side of the core segment is twelve. In embodiments, the number of leaflets comprising the flow control element is three and the number of flange segments on each side of the core segment is nine. In embodiments, the number of leaflets comprising the flow control element is three and the number of flange segments on each side is six.
• In embodiments, the number of leaflets comprising the flow control element is three and the number of flange segments on each side is three. In embodiments, the number of leaflets comprising the flow control element is three, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is nine. In embodiments, the number of leaflets comprising the flow control element is three, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is six.
• In embodiments, the number of leaflets comprising the flow control element is three, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is three. In embodiments, the number of leaflets comprising the flow control element is three, the number of flange segments on one side of the core segment is nine and the number of flange segments on the other side of the core segment is six. In embodiments, the number of leaflets comprising the flow control element is three, the number of flange segments on one side of the core segment is nine and the number of flange segments on the other side of the core segment is three.
• In embodiments, the number of leaflets comprising the flow control element is three, the number of flange segments on one side of the core segment is six and the number of flange segments on the other side of the core segment is three. In embodiments, the number of leaflets comprising the flow control element is two and the number of flange segments on each side of the core segment is twelve. In embodiments, the number of leaflets comprising the flow control element is two and the number of flange segments on each side of the core segment is ten. In embodiments, the number of leaflets comprising the flow control element is two and the number of flange segments on each side of the core segment is eight.
• In embodiments, the number of leaflets comprising the flow control element is two and the number of flange segments on each side of the core segment is six. In embodiments, the number of leaflets comprising the flow control element is two and the number of flange segments on each side of the core segment is four. In embodiments, the number of leaflets comprising the flow control element is two and the number of flange segments on each side of the core segment is two.
• In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is ten. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is eight. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is six.
• In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is four. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is twelve and the number of flange segments on the other side of the core segment is two. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is ten and the number of flange segments on the other side of the core segment is eight.
• In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is ten and the number of flange segments on the other side of the core segment is six. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is ten and the number of flange segments on the other side of the core segment is four. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is ten and the number of flange segments on the other side of the core segment is two.
• In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is ten and the number of flange segments on the other side of the core segment is two. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is eight and the number of flange segments on the other side of the core segment is six. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is eight and the number of flange segments on the other side of the core segment is four.
• In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is eight and the number of flange segments on the other side of the core segment is two. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is six and the number of flange segments on the other side of the core segment is four. In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is six and the number of flange segments on the other side of the core segment is two.
• In embodiments, the number of leaflets comprising the flow control element is two, the number of flange segments on one side of the core segment is four and the number of flange segments on the other side of the core segment is two.
• FIG. 26 shows and alternate embodiment wherein thecore segment106 is ovular rather than circular and thus the core segment is a cylindroid or elliptic cylinder rather than a simple cylinder. This embodiment is more conducive to a bicuspid (or “duckbill”, bivalve, or two-leaflet) configuration for the flow control element. The duckbill configuration is generally referred to asflow control element104 in this figure. The inventors have found that the bi-valve configuration is able to open more fully when coupled with a core segment in the shape of a cylindroid.
• FIGS. 27 and 27A show another embodiment of an interatrial device having intermediate flange segments for a more secured fit against the septal wall. In embodiments, the intermediate flange segments are part of another a third annular flange situated on the same side of the septal wall as one of the other flanges.Reference numerals6000 through6040 refer to steps in the deployment of such an embodiment and will be discussed in connection with the structural features of the embodiment to illustrate this embodiment's utility and operation. The deployment process is similar to those described above, and to any commonly-known catheter based delivery process and as such the details of the process will not be discussed herein.Steps6000 to6020 show the deployment process steps proceeding in much the same manner as described herein. Atstep6030,intermediate flange segments602 and604 of intermediate (or third) annular flange are deployed on the RA side. In this embodiment,intermediate flange segments602 and604 are shorter than the majority of the flange segments of the RA-side flange. As such,segments602 and604 are deployed prior to other longer segments and contact theseptal wall107 at points closer to the septal opening than the contact points of the longer segments. In this manner, theintermediate segments602 and604 (and the flange which they comprise) provide increased stability of the device. Any number of intermediate segments may be used although it is preferable to have at least two. As with other embodiments, the stiffness of the intermediate segments may be altered so as to differ from other flange segments of the device to avoid damage to the septal wall, i.e., lesser stiffness/greater flexibility, or to provide increased stability, i.e., greater stiffness/lesser flexibility. The choice of stiffness/flexibility variations must be balanced against the desired goals.
• FIG. 27A is a side elevational view of embodiment discussed in connection withFIG. 27. InFIG. 27A the pressure venting device in its stowed configuration.Flanges102 and103 are shown with the flange segments that comprise them (flange segments not individually labeled). Core segment is again shown as106. At a point between the end of thecore segment106 and proximal end of the RAside flange segment102, the intermediate segments (collectively referred to as600) emerge. Intermediate segments may be integral with the venting device or attached thereto in the manners described above.
• In other embodiments, the flow control element is configured to direct the blood flow in a desired direction.FIGS. 28A through 28C show such embodiments. InFIG. 28Ainteratrial device100 is shown implanted in theatrial septum107 of the heart in the same manner as shown inFIG. 1.Flow control element104 is configured to aim the, shown in this figure as in the direction toward the superior vena cava.FIGS. 28B and 28C show a more detailed view of embodiments that enable the flow to be directed in a desired direction. As shown inFIG. 28B, flow control element comprises a baffle-like flange104a that extends at a downward angle and in the corresponding direction. In use, such embodiment directs the flow downward.FIG. 28C shows an embodiment where the flow is directed upward. The valve material (e.g. material for leaflets) can be sized and secured to the100 in manner to direct the flow. For example, the flow control element may contain a curved tubular member whose opening points toward the direction of flow, or the flow control element may otherwise comprise an opening directed at the area of interest. In embodiments with baffles, the stiffness of the baffle104a may be varied, for example, made stiffer. The length of the baffle can also be varied depending on the desired flow direction. The baffle can be a separate member attached to the flow control element or it may be made of the material and/or integral with the remainder of the flow control element.
• FIGS. 29A through C show exit profile shapes of theflow control element104. In these figures, theflow control element104 is being viewed from the RA side and thus the direction of flow is understood to coming out of the page at an angle substantially normal to the page. If the flow control element is a valve as described herein, folding and suturing patterns may be employed to achieved these exit profile shapes. In other embodiments, the end of the flow control element may be provided with a plate, or a partially frustoconical end piece, having an opening defining the two-dimensional shape shown in the Figure. The skilled artisan will appreciate that other exit profile shapes may be fashioned. The selection of an exit profile shape may provide advantages such as directing flow, preventing thrombi from moving across the septal divide, and/or reducing injury to surrounding tissue.
• Another embodiment is shown inFIG. 30. In this embodiment, thecore segment106 andflanges102 and103 of the device are substantially similar those described herein. Instead of the flow control elements described above (or in addition thereto) a tube-like member700 is secured to thecore segment106. Thetube member700 is attached to thecore segment700 in a manner to allow the RA end of tube to extend into the RA in an axial direction, thus the tube's length must be sufficient to extend a distance into the RA. It has been found that thetube700 configured in this manner prevents embolic particles from entering the tube and crossing over the septal divide into the LA. The distance that thetube700 extends into the RA and beyond the plane of the RA-side flange opening (indicated by dotted line) should be at least a 1 mm but may be up to 2 cm in preferable embodiments. Even at relatively short lengths (such as where the tube extends only a few millimeters into the RA), the inventors have noted the surprisingly unexpected result of a reduction of embolic particles passing through. This is due to, in part, the tendency of embolic particles to collect along the surface of the septal wall and move toward the septal opening (or opening of an implanted device) with each cycle of the heart. By extending away from theseptal wall107, the tube provides an effective barrier to the embolic particles that would otherwise travel toward and possibly through the septal opening.
• Placing the Interatrial Pressure Vent or Prosthesis into a Mounting Tool
• FIG. 31 depicts a first embodiment of a mounting and loading tool useful for placing the prosthesis onto a catheter or other delivery device for delivery in vivo to a patient. In this embodiment, mountingtool2001 includes abase plate2002 withorifices2003 for securing other components as shown withfasteners2004 andpin2009. The principal component is aloader body2014, mounted via the outer two fasteners and orifices as shown. A mountingplatform2023 is mounted in the center of the loader body via the third orifice andpin2009.Mounting platform2023 includes alower orifice2026 for mounting to the loader body via the middle loader body orifice withpin2009.Mounting platform2023 also includes a slottedcam surface2024.Pivot2029 mounts to theloader body2014 viapivot pin2028 throughpivot orifice2030 andloader body orifice2016.Pivot2029 andlever2031 mount on the left side ofloader body2014 below theside doors2020, as seen inFIG. 31. Movement ofpivot2029 andlever2031 on the cam surface allows a user to raise and lower the mounting platform. The two opposite positions of the mounting platform are the lower and upper positions, achieved by rotating the pivot to the desired position. In other embodiments, the cam surface may simply be a slot or groove in the side of the mountingplatform2023.
• Theloader body2014 also mounts the other components of the device. The loader body includesinternal side channels2018 for mounting twoside doors2020 and also includesvertical bores2015 and avertical side channel2019 for mountingtop plate2005. Theside doors2020 include acentral orifice2027 in the shape of a semicircle, for closing against the prosthesis, discussed below. The side doors includeshelves2021 on either side for riding against thechannel2018 of the loader body. The side doors each also include aretaining pin2022. The pins protrude throughside windows2017 in the loader body and allow the side doors to slide within the loader body while preventing their complete removal from the assembly.
• Top plate2005 includes atop surface2006, an adjustableinternal iris2011, which functions much like the iris in a camera. The iris has sections that adjust inward and outward to open and to close the central opening of the iris. The adjustable iris decreases the area of the opening and closes in a manner that allows the top section of the implantable device to rest on top of the partially or full closed iris. Opening and closing of the iris is controlled bycontrol lever2013. The top plate includes twovertical rods2007 for mounting in thevertical bores2015 of the loader body and also includes avertical side guide2008 with an elevatingmechanism2010 actuated by atop thumbwheel2012. Raising and lowering via the elevating mechanism allows the user to raise and lower the iris and thus adjust the separation of the left and right flanges of the prosthesis with the iris.
• The mounting and loading assembly is used in the following manner. The loader body is positioned conveniently for the user, with the top plate removed and with the doors open. A prosthesis, such asprosthesis100, is placed on the loading platform, with the left atrium legs or flange facing downward and with the loading platform in the lower position. Thedoors2020 are then closed, with the mounting platform still in the lower position, thus placing the left atrium flange below the doors. The mountingplatform2023 is then raised to its upper position by rotatingpivot2029, causing the lower portion (left atrium flange or legs) to be pressed against the under side of thedoors2020. While not shown inFIG. 31, this movement causes the legs of the left atrium flange to be radially spread out.
• At this point, the top plate is assembled to the mounting and loading tool and a catheter, such as one of the catheters depicted above inFIGS. 10-12, and also described above, is introduced though the center of the prosthesis. The portion inserted includes the catheter tip and a portion of the catheter control wire connected to the tip. The position of the catheter is adjusted so that the right atrium ball (“RA ball”) or other retention device is vertically aligned with the right atrium flange, as discussed above with respect toFIG. 11A. The iris is then partially closed. Vertical alignment may be achieved by raising thetop plate2005 usinghandwheel2012. With thedoors2020 closed and the left atrium flange trapped below the doors, raising the top plate will stretch the prosthesis, separate the left and right atrium flanges, and also stretch the prosthesis over the catheter. In one embodiment, the diameter of the orifice made by the two half-circular cut outs2027 of the side doors is about equal, or slightly less than, a diameter of the catheter intended for use as a delivery device for the prosthesis discussed herein. The diameter may range from about 3 mm (9 Fr) to about 7 mm (21 Fr).
• As the iris is raised, the upper (right atrium) flange will approach the retention device, such as the RA ball and the outer sheath of the catheter. The iris may continue to be closed while the top plate is raised, thus bringing the RA flange into contact with the RA ball. If the mountingplatform2023 has not been fully raised, it may also be raised gradually during this process. The entire sequence may be achieved by sequential use of the mountingplatform2023 andpivot2029, theiris2011 and handle2013, and the elevatingmechanism2010 andthumbwheel2012. When the RA flange has closed over the RA ball, the outer sheath may then be brought over the RA flange, securing the end of the prosthesis in the outer sheath. At this point, theiris2011 may be opened along withdoors2020 and the catheter and prosthesis removed from the mounting and loading tool. The inner wire, firmly attached to the catheter tip and RA ball, is then retracted, pulling the central portion of the prosthesis and the LA flange into the outer catheter.
• The catheter is then processed as discussed above, including assembly to a control device or handle, packaging, and so forth. This process is desirably performed in a sterile environment, with all components, tools, fasteners, and so forth, scrupulously clean and sterile before and during all steps of the process. The mounting and loading tool depicted inFIG. 31 and described above is desirably made from an inert, lubricious and medically-acceptable plastic material, such as a fluoropolymer, fluorinated ethylene-propylene, PTFE, UHMWPE, acetal, polycarbonate, and so forth.
• In addition to the mounting and loading tool discussed with respect toFIG. 31, there are other embodiments for mounting a prosthesis and for loading a prosthesis onto a catheter or delivery device. Additional embodiments of useful tools are discussed below. In the discussion below,FIGS. 32-34 concern a discrete mounting tool, whileFIG. 35 concerns a separate tool for loading a mounted prosthesis onto a loading tool.
• FIG. 32 depicts amounting tool2500 useful for mounting a prosthesis for relieving intracardial pressure for a mammal, such as a human. The mounting tool includes four principal components. The principal components include a mountingplate2501, a star-shapedcutout plate2511, a lowerflat disc2521, also known as a right atrium or RA disc, and anupper counterbored disc2531, also known as a left atrium or LA disc. The four components are used and stacked in the manner depicted in the drawing, in combination with a prosthesis mounted on the tool. All four components are desirably made from a lubricious, non-allergenic, medically-acceptable plastic, such as a fluoropolymer, fluorinated ethylene-propylene, PTFE, UHMWPE, acetal, polycarbonate, and so forth.
• Mounting tool2500 includes mountingplate2501 having acylindrical bottom disc2503, the disc having a central raisedportion2505 and an additional raisedportion2507 atop the central raised portion.Plate2501 also includes a plurality ofinserts2502 for attracting and joining with a similar number of inserts incutout plate2511. The inserts may be magnets or a combination of magnets and magnetically-attractive materials.
• Star-shapedcutout plate2511 includes a flattop surface2512 with a cutout in a general shape of astar2515. While the cutout has the general shape of a star, it is understood that the shape need not be a perfect star with perfectly equal sides and perfect angles between all legs or sides of the star. For example, the tips and corners of each point of the star are rounded rather than sharp. This avoids scratching the prosthesis and also avoids any scratching of personnel assembling the prosthesis to a catheter. A cutout in a general shape of a star is sufficient to accomplish the task described herein. The skilled artisan will appreciate that the shape would be appropriate for accommodating the shape of the device.
• The bottom surface includes acounterbore2514 for most of the entire bottom surface. A counterbored surface typically has an abrupt or right-angle termination, such as achieved by molding or by machining with an end-mill or other flat-bottomed tool. The counterbored surface is preferable to a more gradual change, such as a funnel-shaped countersink or angled approach. As discussed below, the counterbored surface of the cutout plate is used to mount the cutout plate to a loading tool. Thus, having the walls of the counterbore straight rather than angled is helpful, because with sufficiently close tolerances, the counterbore aids in firmly securing the cutout plate to the loading tool used. It is possible, however, that angled walls, i.e., a countersink, may be used instead.Cutout plate2511 also includes a plurality ofinserts2502 matching the plurality of inserts in mountingplate2501. In one embodiment, the inserts are polar magnets, i.e., N-S magnets with the poles arranged so that the discs can only be joined in one way.
• For example, mountingplate2501 may have eight N-S magnets molded into the plate with the north poles on the top side, with the raised portions. Ifcutout plate2511 has the magnets similarly mounted, north poles on top, south poles on bottom, then the south poles on the bottom ofcutout plate2511 will attract the north poles on the top side of mountingplate2501, and the two plates may be joined. Because of the polar orientation, there will be no magnetic attraction if one tries to assemble the discs in the incorrect manner, i.e., with the counterbored surface on top. In another incorrect orientation, with thecutout plate2511 below mountingplate2501, the plates will be magnetically attracted for assembly, but the star-shapedfeature2515 will be positioned away from the raisedportions2505,2507. A user will not be able to position the prosthesis on the mounting tool using both the raised surfaces and the star-shaped cutout. Thus the mountingplate2501 and thecutout plate2511 have been designed for assembly and for fool-proof assembly.
• Right atrium disc or lowerflat disc2521 is made as a two-part assembly, aright half2522 and aleft half2523. There is acentral orifice2525 and the disc has a chamfer orbevel2526 on its side. Each side of each half has threebores2527 within the disc and perpendicular to a radius of the disc, the three bores on each side used to assemble the halves. In one embodiment, the outer two bores are used for magnets to attract the halves together and the central bore is used for a dowel to align the halves. Thus, in one embodiment,right half2522 has threebores2527 as shown, the central bore being merely a void for accepting a dowel from the left half, and the two side bores filled with two north-south magnets with the south poles facing outward.Left half2523 has threebores2527 on each side, the central bore on each side filled with a protrudingdowel2528 and the two side bores filled with two north-south magnets with the north poles facing outward. Use of the dowel and the void may be considered as a male-female joint. When the two halves are brought into contact, the opposite poles of the magnets will attract and the two halves will be firmly joined.
• Theleft atrium disc2531, also known as the upper counterbored disc, is also formed as two halves,right half2532 and lefthalf2533.Counterbored disc2531 has acounterbore2534 on top, the counterbored or void portion removing material from a majority of the top surface. There is a chamfer orbevel2536 on the side of the disc toward the bottom, such that when counterboreddisc2531 is assembled with lowerflat disc2521, there is a “V” in profile, the “V” formed by the bevels or chamfers on the two discs.Counterbored top disc2531 also has acentral bore2535 of about the same diameter ascentral bore2525 of lowerflat disc2521. Each side of the halves includes threebores2537 within the disc, the bores perpendicular to a radius of the disc. The bores are voids for accepting devices for joining the two halves, as discussed above for the lower flat disc. In one embodiment, the central bores include a dowel and a void for aligning the two halves, while the outer bores includemagnets2502 with oppositely-facing poles for attracting each other. The dowel and void function for assembly as a tab and a slot in both the right andleft atrium discs2521,2531. The bores may themselves be considered a slot, for use with a dowel, a tab, a magnet or a magnetic material. The tabs may be made of a plastic material or may be made of durable stainless steel or other non-corroding, medically-acceptable material.
• In other embodiments for the side bores on either thelower plate2521 or theupper counterbored disc2531, the inserts could include magnets on one half and steel or iron bars on the other half, or one magnet and one steel bar on each half, with a facing magnetically-attractive metal and magnet on the other half.
• In one embodiment, the lowerflat disc2521 may be made a different height than the height of theupper counterbored disc2531. The difference in heights makes it unlikely that an improper assembly could occur between one half of the lower flat disc and one half of the upper counterbored disc. In one embodiment, the magnets of the halves with the central dowels may be assembled with the north poles outward, while the magnets of the halves with the central voids may be assembled with the south poles outward. This would make mis-assembly of the lowerflat disc2521 and theupper counterbored disc2531 very difficult, since two pieces with dowels (male portions) would be impossible to join. While the two pieces with voids may be magnetically attractive and may join to form a mis-assembly, there would only be one assembled disc, since the two halves with the dowels could not be joined. Thus, use of the magnets and dowels makes assembly of the discs virtually error-proof.
• Mounting tool2500 is used to orient a prosthesis for placement in a loading tool, as discussed below. In practice, a prosthesis for placement in a patient's heart is placed on the mountingplate2501. In one embodiment, a right atrium (RA) flange is placed on thecentral portion2505. The star-shapedcutout plate2511 is placed atop the mountingplate2501, with the points of the star placed atop the flange joints of the RA flange, thus locking the prosthesis in place with the oppositely-facing magnets. The left atrium (LA) flange and the barrel, or central portion of the prosthesis, now stand above the raisedportions2505,2507 of mountingplate2501. Theright atrium disc2521 is now joined to the assembly between the right atrium flange (lower portion) of the prosthesis and the left atrium flange (upper portion) by bringing the two halves together, such that thebevel2526 is on the upper side of thedisc2521.
• Theleft atrium disc2531 is then added to the assembly atop the right atrium disc, also by bringing the two halves together. In this instance,bevel2536 of theleft atrium disc2531 faces downward. The chamfers or bevels of the two discs are thus adjacent when the mountingtool2500 is assembly correctly, the bevels together forming a “V” which will be used later by the loading tool, as discussed below. The mountingplate2501 and the star-shapedcutout plate2511 may then be removed. When the prosthesis has been placed correctly on the mounting tool and the mounting plate and cutout plate are removed, the left atrium flange protrudes from the left atrium disc and the right atrium flange protrudes from the right atrium disc, as seen inFIGS. 33-34.
• The mounting tool is depicted inFIG. 33 after it has been assembled with aprosthesis100. The mounting tool includes mountingplate2501 withcutout plate2511 atop the mounting plate, and withright atrium disc2521 atopleft atrium disc2531. In this figure,prosthesis100 is mounted withleft atrium flange103 visible on top. Note the counter bore2534 visible in theleft atrium disc2531. This is the configuration immediately after the prosthesis has been mounted and the left and right atrium discs have been inserted to separate the left and right atrium flanges. Note also that bevels2526 and2536 are adjacent, forming a V when seen from the side.
• InFIG. 34, the mounting and cutout plates have been removed and theassembly2560 has been inverted, withright atrium disc2521 atopleft atrium disc2531 and with theright atrium flange102 of theprosthesis100 on top. Note that theright atrium disc2521 is flat and has no counterbore on the side seen in this view.
• Loading the Prosthesis into a Loading Tool
• After the prosthesis has been mounted, a loading tool may be used to assemble the prosthesis and place it into a catheter or other delivery device. A loading tool useful in this process is depicted inFIG. 35 and is herein described.
• Loading tool2600 includes abase plate2601, side door supports2611 and2621, acentral column2641 and atravel subassembly2650. The base plate, side door supports and central column each mount to the base plate viafasteners2604, as shown. In one embodiment, the fasteners may mount through the bottom and the heads may reside in countersunk or counterbored recesses in the bottom of the base plate. The base plate also includes a travel control mechanism orthumbwheel2606, includingtravel screw2607 andspacer2608. In this embodiment, thetravel control mechanism2606, and the thumbwheel travel adjuster are mounted within the base plate, and a portion of the handwheel protrudes through a side of the base plate. Rotating the thumbwheel allows one to advance or retracttravel screw2607 and thus raise orlower travel subassembly2650.
• Side doors2631 are identical and reside on side door supports2611,2621.Main doors2660 are also substantially identical and reside ontravel subassembly2650. In one embodiment, door supports2611,2621 each include atop shelf2613 for capturing a side door and allowing it to ride back forth, to and fro. In addition, door supports2611,2621 also each contain a travel stop orpin2615,2625. The pin stands in agroove2637 within the side door, the pin limiting travel of the door to that allowed by the grooves, e.g., the half-way mark of thecentral column2641 and its concentrictop surface2643, on the one side, and retreat from the central column in the opposite direction when appropriate. In this manner, the side doors can slide back and forth symmetrically to meet each other. The side doors have ataper2633 on their front, as well as a half-circular cutout2635 on the front. Eachside door2631 also has avertical pin2636 for ease of moving the door back and forth and also limiting the forward travel, when the pin touches theshelf2613. In one embodiment, the diameter of the orifice made by the two half-circular cut outs is about equal, or slightly less than, a diameter of a catheter intended for use as a delivery device for the prosthesis discussed herein. The diameter may range from about 3 mm (9 Fr) to about 20 mm (60 Fr).
• Main doors2660 mount atop thetravel subassembly2650 via main door mounts2651,2652. The main doors slide back and forth in a manner orthogonal to the side doors. In this embodiment, the main doors are somewhat larger than the side doors and are used to compress the prosthesis to a diameter suitable for a catheter with a similarly desirably small diameter for delivery to a patient. The front portion of the each of the main doors thus includes atransition2664 to a frontalsemicircular arc2665 and asemicircular bore2666 with a radius consistent with such a small diameter. In one embodiment, the desired diameter is about 3.3 mm or 10 Fr, and the radius of the front bore is thus about 1.65 mm. In other embodiments, the radius is from about 1 mm to about 4.5 mm, to accommodate delivery catheters from about 2 mm to about 9 mm, and for catheters with a similar diameter.
• Thetravel subassembly2650 mounts to the loading tool via an internal threadedbore2657 that interfaces with threadedscrew2607. Movement of thethumbwheel2606 movestravel subassembly2650 up and down as desired.Travel assembly2650 includes door mounts2651,2652 includingtongues2654 atop the mounts and pins2653 for limiting travel of the main doors. Themain doors2660 are substantially identical and include agroove2661 along their length of their bottom.Tongues2653 ride withingrooves2661 of the main doors.
• The main doors also include locking pins2663. Each pin may be used to lock themain door2660 into the closed position by closing the door fully and depressing the pin to engageorifice2655 in door mounts2651,2652. Thepins2663 may also be used to restrain each door away from the closed position by opening the main doors and depressing the pins outsidetravel subassembly2650 so that further inward travel is not possible with the pins depressed.Central column2641 with mountingsurface2643 mounts to thebase plate2601 via acentral orifice2645 and a fastener from below the base plate. The central column is positioned symmetrically withinorifice2656 of thetravel subassembly2650. The central column and the mounting surface are stationary, while around them thetravel subassembly2650 travels vertically andside doors2631 andmain doors2660 move horizontally.
• Loading the Prosthesis into the Catheter
• The loading tool is used in the following manner, in one embodiment. Other embodiments and other methods may also be used.
• The side doors and main doors are opened to their full open positions and the mountedprosthesis assembly2560 described above is placed onto central columntop surface2643, with the right atrium flange or legs up and the left atrium flange down. Note that in this configuration, theleft atrium disc2531, which is the disc with thelarge counterbore2534, faces downward. In one embodiment, the counterbore is sized and oriented to fit precisely onto top mountingsurface2643 of theloading tool2600, discussed below.Top surface2643 is the mounting or loading surface for placing the mountedassembly2560 into theloading tool2600.
• Once the mountedassembly2560 is placed into theloading tool2600, thetravel subassembly2650 is raised or lowered so that the side doors align with the “V” formed by the bevels or “V” of the mounted assembly. Theside doors2631 are then closed, bringing the tapered front portions of the side doors into contact with the “V” and urging apart the left atrium and right atrium discs of the mounting tool. Themain doors2660 are then closed against theside doors2631.
• Once this has been accomplished, adelivery catheter2040 is assembled to the prosthesis, as depicted inFIG. 36. Aclear loading tube2561 is moved over theouter sheath2563 and the tip (not shown inFIG. 36) of thecatheter2040 is inserted through the central bore of the mountedassembly2560. Visible inFIG. 36 is theinner sheath2565,inner control wire2569 andright atrium ball2567. As seen in the figure, theright atrium ball2567 should be aligned with theright atrium flange102. Thethumbwheel2606 is then adjusted so that themain doors2660 are above theside doors2631, such that themain doors2660 can close. As the closed main doors are raised usingthumbwheel2606, theright atrium disc2521 will rise, and theright atrium flange102 will begin to lengthen axially and compress radially. It may be advantageous to insure that no legs or struts of the flange are intermingled or caught in the disc or the doors as the doors rise.Thumbwheel2606 is used to raise the main doors while the catheter is held in a position that allows the right atrium flange to close around theright atrium ball2567. When this operation has been correctly accomplished, the legs or struts of the flange are evenly and tightly spaced around the right atrium ball or flange.
• The prosthesis is now brought into the catheter. In one embodiment, the following procedure is used. The RA ball acts as a compression device, compressing the right atrium flange. After the right atrium flange is firmly compressed around the right atrium ball, theouter sheath2563 is held firmly while theinner sheath2565 andcontrol wire2569 are pulled back. This pushesouter sheath2563 over the right atrium flange andball2567. Theball2567 should be pulled into theouter sheath2563 so that it, and the right atrium flange, are no longer visible. Thetravel assembly2650 is now lowered, using the thumbwheel, until it just touches the side doors2631 (not shown in this view). Both sets of doors are opened and thecatheter2040 and left andright atrium discs2631,2621 are removed from theloading tool2600. The left and right atrium discs are then removed from the catheter by pulling them apart.
• The left atrium flange is now lengthened axially and compressed radially. In one embodiment, theclear loading tube2561 has a larger diameter than theouter sheath2563. Theclear loading tube2561 is slid over theleft atrium flange103, pushing the left atrium flange legs together. The clear loading tube should be slid forward or distally until it completely covers the prosthesis. Thecontrol wire2569 is then pulled proximally, pulling theinner sheath2565 and pulling the prosthesis intoouter sheath2563. Theclear loading tube2561 is then removed. The above mounting and loading procedures are accomplished in a sterile environment. Alternatively, the devices and components may be sterilized or re-sterilized after assembly.
• Any other desired components, such as an outer shipping sheath, may then be added. In one embodiment, an outer shipping sheath is added in a sterile manner, as shown inFIG. 37, over theouter sheath2563. Sterileouter shipping sheath2571 withconnector2573 andvisible cap2575 is added over theouter sheath2563 in such a way thatinner sheath2565,right atrium ball2567 andright atrium flange102, the central portion ofprosthesis100, leftatrium flange103,inner control wire2569 andtip2570 are visible from the outside ofsheath2571. In the embodiment shown, the prosthesis, including theright atrium flange102 andright atrium ball2567, has been advanced using thecontrol wire2569, or theouter sheath2563 has been retracted, to allow visibility from the outside of the device. Thecatheter2040, with the prosthesis loaded and ready for inspection and deployment, is now ready for shipment to a hospital or other care-giving institution.
• Implanting and Deploying the Prosthesis
• With this embodiment, and in this configuration, a physician can immediately inspect the prosthesis and determine whether the prosthesis is suitable for implantation into a patient. For example, the physician can immediately inspect, without even opening the outer package, whether the legs or struts of the right atrium flange are intertangled. The physician can also determine whether the left atrium flange or center portion are also suitable for implantation into the patient.
• As noted, the shipping sheath is advanced over theouter sheath2653 of the delivery ofdeployment catheter2040. Accordingly, theprosthesis100 remains within the outer sheath at all times during shipping and during removal of the shipping sheath. In some embodiments, the outer catheter is connected at its proximal end to an irrigation system, described below, suitable for irrigating the outer sheath, and thus the prosthesis, with sterile fluid, a radiopaque dye, or other desired solution. A physician can thus remove the shipping sheath, flush the prosthesis with sterile solution using the irrigation system, and move the prosthesis back and forth within the outer sheath. This allows the physician to remove any possible bubbles from the device and the catheter, at the same time allowing the physician to test the level of effort required to advance and retract the prosthesis or the outer sheath with respect to each other.
• Control Systems for Deploying the Prosthesis
• A control system, including a control device or handle, and an irrigation system, may also be usefully employed with the catheter described above. One example of a control system or handle was given above inFIG. 12, and also explained. Another example is depicted inFIGS. 38A and 38B, control system2700, including control handle2701 andirrigation system2720. The control handle2701 includes a housing orgrip2713 and acontrol trigger2715 for a user to retract the outer sheath or advance the inner control wire. The tension or pull required for thetrigger2715 is set withtrigger spring2731. Thus,spring2731 controls the force needed by the user to deploy the prosthesis, i.e., the force required to release the implant onto the septal wall.
• The inner control wire is grounded to the control handle throughfirst plate2711 via theflange2041 of the inner control wire and may also be secured withadjustment screw2715. The position of the first plate within the handle is set by a pin and bore, or set screw or other arrangement (not shown). Thesecond plate2717 is connected to the outer sheath and the irrigation system, which are secured to the second plate viaconnector2722. The second plate is connected via a slot (not shown) on its rear face to a pin (seeFIG. 38B) on the actuation mechanism within the handle. The first andsecond plates2711,2717 have slots or mortises on their rear faces for riding on a tenon orshelf2716 on the side of the front grip cover2714.
• FIG. 38B depicts the internals of the trigger mechanism.Grip2713 also includes a front cover2714. The front cover2714 is assembled to thegrip2713 throughfasteners2724 andorifices2726 in thegrip2713 andmating parts2721 in the cover2714. The mating parts may be molded-in nuts, threaded surfaces, or other appropriate joining components.
• The internals of the trigger mechanism are largely contained within thegrip2713. These include atrigger spring2731, grounded between thetrigger2715 and a pocket in grip1713. As noted,spring2731 determines the pull required to activate the trigger. This spring also provides a return for the trigger to its resting or neutral position after each pull by the user. Mounted within achannel2734 ingrip2713 are a vertical braking/release bar2735,vertical driving bar2737 and a drivenhorizontal bar2738.Trigger2715 also has an internal rectangular bore (not shown) for accommodating drivenhorizontal bar2738.
• Drivenbar2738 in one embodiment has a rectangular cross section, while the driving and braking/release bars2735,2737 have bores with rectangular cross sections and are mounted around the driven bar via the rectangular bores.Bar2738 has a square cross section in one embodiment, as do the matching bores in the braking and driving bars. Other configurations may also be used for thebars2735,2737 and2738, and the corresponding bores. Drivenbar2738 includes apin2739, which is connected directly to a bore (not shown) on the rear of thesecond plate2717.Biasing spring2733 is grounded between the drivingbar2737 and braking/release bar2735, which is somewhat longer than drivingbar2737.Biasing spring2733 maintains compression and separation between the braking and advancing bars.Trigger2715 is also mounted around the drivenbar2738 via a rectangular bore in this embodiment. Other embodiments may include different geometries for drivenbar2738 and the corresponding bores in the trigger, the driving bar and the release/braking bar. These shapes may include rounded rectangular, ovate and others.
• Compression spring2712 biases the braking/release bar2735 to a braking position by maintaining contact between the braking/release bar2735 and drivenbar2738.Release pin2736 protrudes above the top of thegrip2713 and is used by the operator to release the driven bar from the braking and driving bars. When a user wishes to return thesecond plate2717 to a forward position, or to select a position for the second plate, the user simply presses onpin2736. Pressing onpin2736 has the effect of pushing the release/braking bar2735 to the rear by overcoming the compression ofspring2712. Releasing thebraking bar2735 enables easy manual movement of the drivenbar2738 and thussecond plate2717 and the outer sheath of the catheter.
• The trigger mechanism works in this manner, although many other embodiments are also possible, as also discussed in U.S. Pat. No. 7,699,297. When the user activates the control mechanism by pulling the trigger, the drivenbar2738 moves to the rear, to the right inFIGS. 38A and 38B, as does the connectedsecond plate2717. The outer sheath is also connected to the second plate, and as the second plate moves to the right or rear, the outer sheath does also, thus pulling the outer sheath in a proximal direction and exposing more of the prosthesis and the inner control wire. The distance traveled by the activating bar is determined by outer dimensions of the driven bar, the height of the bore in drivingbar2737, the distance between the drivingbar2737 and the braking/release bar2535, and length of the vertical distance in the bore oftrigger2715. These lengths or distances determine the angles between the various components and thus limit the distance that is traveled by the trigger, the driving bar and the driven bar, on each pull of the trigger. Thus, each pull of the trigger moves the drivenbar2738, thesecond plate2717 and the outer sheath of the catheter2653 a predetermined distance. This makes it straight-forward for the medical professional to deploy the prosthesis. Each pull of the trigger will retract the outer sheath or advance the control wire a known and repeatable distance.
• Returning toFIG. 38A, theouter sheath2653 is grounded to thesecond plate2717 viaconnector2722, which provides both a mechanical connection to the control device throughsecond plate2717 and also a fluid connection toirrigation system2720. Theconnector2722 connects to theirrigation system2720 throughtubing2723 to a three-way valve2725. The valve may also includeother tubing connections2723 or to one or more connectors (not shown), and one or moreoptional caps2727. As noted above, the irrigation system may be used by the physician to flush the prosthesis and outer sheath with sterile fluid before use, and to check for and remove and bubbles in the catheter and in the prosthesis. Such fluid will exit at the far end of theouter sheath2653 afterconnector2573 andcap2575 are removed.
• In one embodiment, the control system2700 includes an internal mechanism that determines the amount of movement of the first or second plate when the trigger is pulled, and thus when the outer sheath is retracted or in the control wire and prosthesis is advanced. As noted, the amount of force needed for a single trigger actuation may be set byspring2731. The remaining internal mechanisms, as discussed above, sets the distance traveled. The catheter is advanced to a point where the catheter and the prosthesis are in the desired location within the patient, as determined by the radiopaque methods described above, or by other desirable, reliable method.
• The tip of the catheter is advanced through a surgically-created opening in the atrial septum. The tip is thus in the left atrium at the start of the deployment process. When the trigger is pulled, the outer sheath is retracted a distance sufficient to remove the outer sheath from around the left atrium legs and flange. In embodiments, this distance is about7mm. At this point, the left atrium legs are deployed inside of the left atrium, similar toFIG. 27,step6000, which shows the left flange legs deployed from the outer sheath ofcatheter111 into the left atrium. The entire catheter system is then pulled back such that the left atrium legs contact the septal wall, as seen inFIG. 27,step6010. At this point, the central portion of the interatrial vent and the right atrium legs and flange are still retained by the outer sheath. The central portion, still retained, is located in the septal opening. The right atrium legs, still retained, are located in the right atrium. A second pull of the trigger retracts the outer sheath a distance, about7 mm, to remove the outer sheath from around the central portion and the right atrium legs, thus deploying the central portion and also deploying the right atrium legs in the right atrium.
• While 7 mm is a central value, the actual value may vary from about 3 mm to about 11 mm. In other embodiments, other travel ranges may be used. It will also be understood that this distance may vary, due to tolerance stack ups of the several components, including those of the catheter and the control device.
• At this point, the prosthesis has been deployed, and the physician will normally inspect the deployment by one or more of the non-invasive techniques described above to insure correct placement. If deployment is satisfactory, the physician may remove the catheter and all components, including the tip, the outer sheath, the control wire, and so forth, and finally the guide wire used.
• During implantation, the physician may use the catheter fluid system to determine the precise placement of the end of the outer sheath and thus the prosthesis. After the device has been advanced through the patient to a point near to the desired implantation point, the radiopaque markers on the left or right atrium flanges or the catheter may be used, along with fluoroscopy, echosound or other non-invasive means, to determine the location of the device within the patient. In addition to, or instead of the radiopaque markers, the irrigation system may use a radiopaque solution, such as a barium solution or other radiopaque solution.
• The control device or handle ofFIGS. 38A and 38B is merely one example of a delivery or deployment device and control device, as discussed herein, for use with a delivery catheter. Other control devices may also be used, such as additional examples depicted inFIGS. 39A,39B and40.
• Another embodiment of a control device is depicted inFIGS. 39A and 39B. In this embodiment, as seen inFIG. 39A,control device2790 connects todelivery catheter2788 for delivering a prosthesis.Control device2790 includes acontrol body2791 and acontrol handle2792. Thecontrol body2791 is attached or connected to theouter sheath2784 viaconnector2797. The moveable control handle2792 is attached or connected to an inner control wire2786 (not visible inFIG. 39A) via connector2799, and as seen inFIG. 39B, connected to thedeployable prosthesis2780.Connector2798 is a fluid connector for supplying fluid to the inside ofcatheter2788 and the inside ofouter sheath2784. The fluid may be sterile fluid, or may be a sterile radiopaque fluid.Control handle2792 is equipped with athumb ring2794, while thecontrol body2791 includes two finger rings2796.Handle2792 is also equipped with a protruding bump ortab2793, which is sized and designed for sequential positioning inorifices2795.
• In the sequence depicted inFIG. 39B,control body2791 remains stationary, as doesouter sheath2784, while the control handle2792 moves progressively to the left, i.e., in a distal direction, in a series of discrete steps, as shown. As thetab2793 moves to the left, from the first of theorifices2795, on the right to the last orifice on the left, the tab is visible in one orifice after another, as shown. At the same time,distal tip2785 also moves progressively to the left, distally, to sequentially deploy more and more ofprosthesis2780. In the middle two views, leftatrium flange2787 is first partially deployed and then fully deployed. In the final view, both left andright atrium flanges2787,2789 are deployed. The final view also allows a close-up of the delivery catheter details, includingtip2785 andnon-invasive imaging markers118 on thetip2785, just proximal to the tip, and just distal of the deployedprosthesis2780.
• In this handle, the control handle2792advances control wire2786 and thus theprosthesis2780 in a sequenced manner that is controlled by the spacing a, b, c, between theorifices2795 of thecontrol body2791. In one embodiment, the distances are 16 mm, 5 mm and 11 mm, respectively. Other embodiments may use other discrete distances. These distances help the medical professional who deploys the prosthesis to more accurately position the prosthesis within the patient. The device and sequence shown inFIGS. 39A-39B uses a stationary outer sheath and a moving inner control wire and prosthesis. It is understood that thehandle2792 could alternately be attached to the outer sheath, so that thetab2793 begins in the most distal position, as shown in the last movement of the sequence, and then the handle and tab move proximally to retract the outer sheath, thus deploying the prosthesis.
• In addition, of course, non-invasive imaging is used to position the catheterouter sheath2784 anddistal tip2785 to a desired position within the patient, i.e., with the distal top2785 through an opening in the atrial septum of the patient. Differences between patients may also be studied, and the position of thecontrol handle2792 may be adjusted slightly for optimal prosthesis placement. As noted in other embodiments, markers for x-ray or echogenic imaging may be placed on the prosthesis, on the delivery device, or both, to assist in accurate placement. Using these markers, the medical professional or surgeon implanting the device may make adjustments to the position of the outer sheath, the prosthesis and the relative distances between them. The prosthesis may then be deployed as desired and the implanting catheter, with its tip, inner control wire, and so forth, retracted from the patient.
• InFIG. 40, anothercontrol device2170 includes a hollowcylindrical body2171, with acentral channel2172. There is a series ofbores2173 for use with aset pin2174 to set the position of afront slider2190 with a hollowed-out portion2191 for retaining an outer sheath or outer portion of the deployment device. The outer sheath is anchored withinslider2190 and its motion is controlled by ahand actuator2195 with athumb grip2197 for use in moving the slider backward or forwards. Theslider2190 is connected to thehand actuator2195 via anadapter2175 andpin2178. Thus, the slider, and the position of the outer sheath may be retained in place using abore2192 in the slider and retainingpin2174, along with thehand actuator2195.
• Adapter2175 andpin2178connect slider2190, and an attached outer sheath, to thehand actuator2195.Pin2198, also known as a member, on the bottom surface ofhand actuator2195, restrains the movement of the hand actuator to the paths molded into the outer surface of thecontrol device body2171. These paths includeforward track2184,intermediate track2182, andrear track2179. The lengths of the forward and rear tracks are thus fixed or predetermined distances. The forward andrear tracks2184,1289 are generally parallel and are separated by intermediate,transverse track2182.
• The control wire of the catheter is connected to arear retainer2180 with one or more hollowed-outportions2183 for securing the control wire or inner portion of the deployment device. Therear retainer2180 is easily held in place securely and movably by a molded-inretaining nut2181 and a threadedrod2177. Thehandwheel2176 itself fits snugly into the proximal, enlarged portion of thecylindrical body2171. The handwheel may be pinned in position and may rotate in place to allow translation of therear retainer2180 and thus the inner control wire. Thehandwheel2176 and the threadedrod2177 allow fine adjustments to the position of the control wire with respect to the position of the outer sheath.
• In use, the physician or other medical professional will advance the catheter using the non-invasive imaging techniques already described. The prosthesis is advanced to the point where the catheter tip is in the left atrium, while all portions of the prosthesis remain within the outer sheath. Theslider2190 is fixed in a distalposition using pin2174, the forward or most distal orifice of the series oforifices2173, andorifice2192 of theslider2190. At this point, the hand actuator is at its most distal position, andpin2198 is all the way forward, to the right inright track2184, i.e., the most distal position.
• At this point, the left flange is positioned within the patient's left atrium, still remaining with the outer sheath, and theretainer2180 is locked in position and not moved further. The outer sheath is then retracted using theslider2190 andhand actuator2195, similar to step6000 inFIG. 27. In one embodiment, the outer sheath is retracted by sliding thehand actuator2195 straight to the rear and proximally, or to the left inFIG. 40. This movement is allowed by the rearward movement of member orpin2198 inright track2184. This movement is a fixed distance, until the pin strikes the rear of thelong portion2184 and the start oftransverse portion2182 of the molded-in paths and can go no further. The length of thelong portion2184 is fixed when the long portion is molded or machined into hollowcylindrical body2171. The distance is that needed to deploy the left flange of the interatrial pressure vent or prosthesis. The distance may also be that needed to deploy the left flange and the central or valve portion. In one embodiment, this distance is about 7 mm. In other embodiments, the distance may be 5 mm, 6 mm, 8 mm, 9 mm or other desired distance.
• After the desired portion has been deployed, the physician may use fluoroscopy or echosound to determine the exact position of the prosthesis with the patient before proceeding. If an adjustment is needed, the prosthesis can readily be retracted into the outer sheath for removal or redeployment at this stage, as will be seen in some of the improved designs for retrieval and redeployment described below.
• If continuation is indicated, the surgeon or medical professional will then prepare to deploy the remainder of the interatrial pressure vent or prosthesis. The first step is to rotate the hand actuator2195 a few degrees to the right so thatpin2198 is now in the otherlong track2179. Thetransverse portion2182 is only about twice as wide aspin2198. Rotation of the hand actuator thus does not cause the prosthesis within the patient's heart to translate proximally or distally. The surgeon then moves the hand actuator in a proximal direction, to the left inFIG. 40, further retracting the outer sheath and deploying the right atrium flange into the right atrium of the patient's heart. The length oftrack2179 is also a fixed distance, the distance fixed when the track is molded into the hollowcylindrical body2171. In one embodiment, the distance is 8 mm, a little longer than the length oftrack2184. In other embodiments, the distance may vary, as noted above. The distances, or the length of the tracks, may be tailored to fit the patient's anatomy, for example, by determining ahead of time the width of the patient's septum or the dimensions of the patient's heart.
• In another embodiment, not shown, the two tracks of predetermined length may be a single length with a pin or other obstacle inserted at a desired point along the length of the track. The pin will prevent further movement ofpin2198 in a proximal direction and will stop the movement of thehand actuator2195 after it has moved a fixed or predetermined distance, e.g., 7 mm. After the pin is removed, the surgeon or other medical professional may continue to move the hand actuator in a proximal direction along the remainder of the predetermined or fixed length of the track.
• Retrieval of the Prosthesis
• In some rare situations, the deployment may not be satisfactory for any of a number of reasons, and the prosthesis may be removed from the patient. This very unusual situation may become apparent before the procedure has been completed. In some cases, the need for removal may become apparent while the guidewire with which the procedure was begun is still in place, such, for example, the embodiments described in connection withFIG. 19A. In other cases, it may be necessary to introduce a guidewire to begin a removal procedure, while in other cases a guidewire is not used. If the prosthesis has not been fully deployed, removal is typically accomplished by retracting the control wire attached to the prosthesis, or by advancing the outer sheath over the prosthesis. Removal is then accomplished by merely withdrawing the outer sheath and all its components. Once the prosthesis has been deployed, different techniques may be needed, as depicted herein.
• Retrieval of the fully deployed prosthesis is depicted inFIGS. 41 and 42, while the tools used for retrieval are depicted inFIGS. 41,42 and43. Theretrieval device2750 is advanced to the desired location within the patient along aguidewire2751. Components of theretrieval device2750 include anouter sheath2752, aninner sheath2753 and agrasper2755, such as the three-prong grasper depicted inFIG. 41. In one embodiment, the outer sheath has an outer diameter of about 21 Fr (about 7 mm) while the inner diameter is about 6.7 mm. In the figure, thegrasper2755 has caught theprosthesis2757 with one of the threeprongs2755aand its protruding hook ortab2755b. As noted, thetab2755bmay be useful for insertion into an orifice of a prosthesis leg or strut, as seen inFIG. 2A, for retrieval of the prosthesis. InFIG. 2A, legs103xof the flanges meet at a juncture, an apex or an end of two of the legs. Each flange of the prosthesis includes two or more legs, usually in pairs, each pair also forming an apex where the legs meet.
• It will be recognized that one or more components of the retrieval device may include radiopaque components or markers for better visibility by non-invasive techniques, such as fluoroscopy, echo-sound, and so forth. In one embodiment, one or more of the prongs of the grasper may be made of a radiopaque metal or material, such as the metals themselves or alloys of gold, platinum, palladium, tungsten and tantalum. In another embodiment, the prongs of may include one or more markers, e.g., a small dot or implant of a radiopaque material or echogenic material that will be easily detected by x-ray, fluoroscopy, echosound or other suitable non-invasive imaging technique.
• In use, the retrieval device is advanced to the desired location within the patient, using non-invasive techniques and radiomarkers, echogenic markers, or other indicators on the device. The user has three controls to manipulate the device, in addition to advancing and retracting theentire device2750, e.g., while the internal portions are contained within theouter sheath2752. Theinner sheath2753 has a control wire (not shown) as does the grasper2755 (control wire not shown). Theretrieval basket2758, depicted inFIGS. 42 and 43, also is advanced and retracted using its control wire (not shown), as will be understood by those with skill in minimally-invasive surgery arts. Thegrasper2755, as the innermost component and nearest the guide wire, may have a micro-rail, i.e., a lumen or longitudinal cavity, to follow precisely the path of the guide wire. In other embodiments, it is possible to assemble the retriever so that an inner sheath is not used. For example, if the basket is assembled proximally from the grasper, and the grasper sufficiently distal from the basket, an inner sheath and its control wire may not be needed.
• The user advances thedevice2750 andouter sheath2752 near the desired point and verifies the location. The user may then advance theinner sheath2753 out from theouter sheath2752. The user may then advance thegrasper2755 from the inner sheath and maneuver the grasper and the inner sheath, or the grasper or the sheath separately as desired, to grasp theprosthesis2757 with the prongs of the grasper. There is no separate closing control for the grasper. The user simply maneuvers the grasper in such a manner that when the grasper is retracted, the prongs approach each other in a manner to grasp and retrieve the prosthesis. The control wire or control handle for the grasper in one embodiment has a locking feature that allows the surgeon to close the grasper and not be concerned about further manipulation of the grasper, except for withdrawal. In one embodiment, the grasper is a three-pronged Hobbs forceps, available from Hobbs Medical, Stamford Springs, Conn., USA. In another embodiment, the grasper or the retrieval device may also have a fluid channel for irrigating the retrieval site, much as the deployment catheter has a fluid channel.
• Other graspers or retrievers may be used instead, such as those with four prongs, or even other retrieval devices, such as a single prong or tab. The single tab or prong may be in the form of a short cylinder, suitable for insertion in an orifice of the struts or legs of a flanged atrial septum implantable device, as shown inFIGS. 2A and7B. The user maneuvers the grasper or tool so that the implantable device is hooked by one or more of the orifices, and then uses this connection to retrieve the implantable device.
• In other embodiments, the implanted device may have one or more legs of the right atrium flange longer than most legs of the flange, making it easier to grasp one or more of the legs or struts, as shown above inFIGS. 7B and 7C. In these embodiments, the grasper may more easily approach the implanted device and grasp it, whether a multi-prong grasper is used, or whether a single tab or prong is used to grasp the longer leg. In other embodiments, the implanted device may have a flange more suited for retrieval, such as the conical flanges depicted inFIGS. 22 and 23. In these embodiments, it is relatively easy for a user to grasp theconical apex450 for retrieving the implant via a grasper, as discussed above. Retrieval is more user-friendly also, since the shape of the implant lends itself to being pulled in the proximal direction, i.e., towards the outside of the body of the patient.
• The inner sheath and the grasper are then retracted, as shown inFIG. 42, and thebasket2758 is deployed by advancing its control wire (not shown).Basket2758 may be made from metal mesh, such as Nitinol or other medically-acceptable, shape-memory material. Nitinol is a good choice because it can be trained to assume the desired basket form as it deploys from the outer sheath. There may also be abarrier layer2759 to help prevent any undesired piercings by wires or components of the prosthesis. The barrier layer may be made of a suitable medically-acceptable cloth, such as polyester (Dacron®, for example), or other material. Once the prosthesis is grasped and the basket deployed, thegrasper2755 and the prosthesis may be retracted into the basket by advancing the basket or retracting the grasper and prosthesis, or both. The basket, grasper and prosthesis are all withdrawn into the outer sheath, which may then be safely removed from the patient with the retrieved prosthesis.
• As noted, basket2858 may be made from metal mesh, such as a mesh made from Nitinol or other wires. In one embodiment, Nitinol wires may be 0.003 inches in diameter (about 0.08 mm in diameter); in another embodiment, the wires may be 0.020 inches in diameter (about 0.51 mm in diameter). Other embodiments may use flat wires or ovate-shaped wires.Basket2759 is made from a single layer of Nitinol mesh. Other embodiments, such as the one depicted inFIG. 43, may use abasket2760 having two layers, i.e., a basket including aninner layer2761 folded over to form a second,outer layer2762. The two-layer basket may be better at preventing objects within the basket from protruding outside the basket.
• Retrieval Devices with Dilators
• It is clear that the outer sheath of a retrieval device, and all components, should be as small and as thin as possible for patient comfort. Accordingly, in one embodiment, the outer sheath has an outer diameter of about 18-20 Fr. In one embodiment, the deployed basket has a largest outer diameter of about 20 mm, which is quite large compared to a 20 Fr outer catheter outer diameter. In other embodiments, the sizes may be larger or smaller, as needed. It is clear from inspection of the basket inFIGS. 42 and 43 that the space used to accommodate devices for retrieving the prosthesis will be somewhat greater than the space typically used to deploy the prosthesis.
• In order to ease the transition, a retrieval device may use a dilator on its distal end. While the tip is nominally termed a dilator, it does not expand, rather its purpose is to maintain the dimension of its widest portion while the forceps or other device within the sheath is deployed behind the tip. Two embodiments are depicted inFIGS. 44 and 45. InFIG. 44,retrieval device2765 includes anouter sheath2766 anddevice tip2767. The device is introduced into the patient via aguidewire2771.Retrieval device2765 includes a grasper orforceps2768, a jacket orouter covering2769, as discussed above, and abraided capture sleeve2770, such as a capture sleeve made from Nitinol mesh.Retrieval device2765 also includes X-ray orechogenic markers2774 in useful locations, such as at the distal end of theouter sheath2766 or thedilator2767.
• In use, the device tip is deployed when the user pushes theforceps2768 distally, or withdraws theouter sheath2766 in a proximal direction. The device tip is constrained to move axially along theguidewire2771, and its location will thus remain in the control of the medical professional deploying or retrieving the prosthesis.
• The embodiment ofFIG. 44 features a device tip with a rather long transition section. When the user has advanced the retrieval device to the desired location within the patient, the sheath is withdrawn in a proximal direction, or the forceps is advanced in a distal direction to deploy the forceps and the basket. Because the device tip has a very gradual transition, the movement and the disruption to the patient are minimal. In this embodiment, the angle A of the device tip may range from about 10 degrees to about 30 degrees. Other angles may be used. The length of the transition section may vary from about 15 mm to about 25 mm. Other lengths may be used.
• Another embodiment is depicted inFIG. 45. In this embodiment, theretrieval device2775 also has anouter sheath2776 and aseparable device tip2777. As shown in this view, the angle of the device tip is much greater than the previous embodiment, while the length of the device tip is much shorter.Retrieval device2775 includes aninner sheath2781 and aballoon2782 and an inflation/deflation lumen2783.Retrieval device2775 also includes X-ray orechogenic markers2779 in useful locations, such as at the distal end of theouter sheath2776 or thedilator2777. The length of the transition section may vary from about 5 mm to about 120 mm. Other lengths may be used.
• In this embodiment, the retrieval device is used with the device tip and the internal balloon that is inflated to create a space for the retrieval device. In this embodiment, theretrieval device2775 does not include a retrieval forceps at the outset. After the device tip is deployed and the balloon is expanded to create a space, the balloon is deflated and retracted and a retrieval forceps and basket are exchanged along the guidewire for the balloon and the inflation equipment. The balloon may be expanded by inflating the balloon to a pressure from 6 atm to 20 atm.
• Designs for Retrievability and Redeployability
• FIGS. 46-49 depict additional embodiments of interatrial implantable prostheses which have been designed for easier retrieval and also for redeployment once they have been retrieved. A firstimproved embodiment100ais depicted inFIGS. 46A-46B. The drawings depict several views ofbody element100a, showing how the ends offlange segments102a-102h,103a-103hare rounded at theirdistal ends115 and116 to reduce stress concentrations against the interatrial septum after placement. These distal ends, or apices where the strut legs intersect, includebores109a,109b,110a,100binto which radiopaque orechogenic markers118a,118band119a,119bcan be positioned. Using these markers, the device may more easily be visualized using radiographic imaging equipment such as with x-ray, fluoroscopy, magnetic resonance, ultrasound or other imaging techniques. Markers as disclosed herein may be applied to the ends of any segments, not just those with holes or eyelets therein. Radiopaque orechogenic markers118a,118b,119a,119bcan be swaged, riveted, adhered, or otherwise placed and secured into the bores and dimensioned to be flush with the contours of the segments. As noted previously, suture rings117a,117bmay be used to secure the leftatrium flange segments103a-hto the rightatrium flange segments102a-h.
• The retrieval legs described herein may be made from nitinol wire, stainless steel wire (such as grades 304, 304L, 316 and 316L, among others), nylon sutures (e.g., polyamide), polypropylene sutures (e.g., Prolene®), or any other material that is medically acceptable and resistant to stretching. Materials that assume a known shape are desirable, as are materials that are visible under echographic or x-ray imaging conditions. The legs may thus take on a filamentary, thread, suture or wire shape, and may comprise a single thread or wire, or more than one suture, filament or wire. Wires made from nitinol or other metals may have a thickness from about 0.004 to 0.025 inches (about 0.11 to 0.64 mm). Sutures may range from about 8-0 to 7 (U.S.P. designations), i.e., from about 18 to 40 AWG, or even a little thinner than 40 gauge. The diameters of such sutures will range from about 0.04 mm to about 0.8 mm, and may apply to collagenous materials, synthetic absorbable materials, and synthetic non-absorbable materials.
• FIG. 46A depictsseveral retrieval legs135 joined to acentral nub137. The retrieval legs may be made of nitinol wires or of sutures and may extend from thebores109 of rightatrium flange legs102a-hto a central juncture ornub137. Portions of the sutures or wires may be made from radiopaque materials or MR-visible materials so that thenub137 is visible using non-invasive imaging techniques. At a juncture, the retrieval legs may be joined into ashort tube175 and crimped intotube175. A single suture orwire loop177, or more than one loop, may then extend above the crimp for joining to the inner catheter control wire, or for grasping by a retrieval device. A typical crimp tube is visible under x-ray or echographic (sound) imaging. Thus, the tube may be stainless steel or radiopaque plastic. One embodiment of the tube has a 0.035 inch i.d. (0.90 mm), 0.008 in (about 0.2 mm) wall thickness, and about a 0.050 inch (1.3 mm) o.d. Other embodiments may be used.
• Retrieval loop177 may be radiopaque or echograpically visible, or may include one or more threads that are radiopaque or echo-visible, such as a gold or platinum thread. The retrieval legs of this design do not interfere with the function of the prosthesis but do extend a short distance proximally, as shown inFIG. 46B. Thus, a filter, such as a thrombus filter, may be used as part of the prosthesis. In addition, the septa described above may be used in the central portion of the prosthesis. These include the bivalve ofFIG. 26, or a tri-lobal valve, or other embodiments, such as those discussed above with respect toFIGS. 29A-29C.
• The prosthesis ofFIGS. 46A-46B was deployed from a catheter, as described above, and is retrieved in a similar manner, described below. The retrieval device secures suture orwire177 from the central tube or crimp175 with an appropriate end-effector, hook or grasper on its inner control wire. The inner wire of the retrieval device is then withdrawn proximally, drawing the sutures or wires into a catheter, collapsing the right atrium flange, and then drawing the remainder of the prosthesis into the catheter. The device may then be withdrawn from the patient, or may also be redeployed, perhaps in a better position.
• A second design specifically for retrievability is depicted inFIGS. 47A-47B.Prosthesis141 is similar toprosthesis100aofFIGS. 46A-46B.FIG. 47A is a top view, depictingprosthesis141 with retrieval wires orsutures143 connected to theapices102a-hof the right atrium flange. In this embodiment, there are two central nubs or points145, each for about 180 degrees of the flange. Theretrieval wires143 are tied together to form anub145 on each side of the right atrium flange. As seen inFIG. 47B, thenubs145 are then joined with acrimp tube175, with aloop147 of one or more retrieval wires or sutures joining the twocrimp tubes175 and sides of the prosthesis for removal. The retrieval wires or sutures, and the nubs, may be made from the materials described above. As depicted inFIG. 47B, the wires or sutures avoid the central area of the prosthesis when deployed fromcatheter173 and thus do not interfere with the functioning or deployment of the valve. The wires or sutures are available to assist in withdrawal and removal or redeployment of the prosthesis if needed.Retrieval loop147 may be radiopaque or echographically visible, or may include one or more threads that are radiopaque or echo-visible, such as a gold or platinum thread.
• A third embodiment of a design for retrieval is depicted inFIGS. 48A and 48B. In this embodiment,prosthesis151 is very similar toprosthesis141 above, including retrieval sutures orwires153 frombores109 of the rightatrium flange apices102a-h, to a central annular retrieval suture orwire157. Each retrieval suture orwire153 is joined to thecentral retrieval thread157 at ajuncture155. The junctures may simply be suture tie-offs; alternatively, the junctures could be orifices incentral wire157 for joining retrieval sutures orwires153. In some embodiments, an additional retrieval suture orwire147, suitable for non-invasive imaging, may be tied to the central thread at least at one point for grasping by a retrieval device.
• A fourth embodiment of aprosthesis161 designed for retrieval and redeployment is depicted inFIG. 49.Prosthesis161 is similar toprosthesis100a, described above. In the fourth embodiment, there is a retrieval wire orsuture163 secured to each apex102a-hof the right atrium flange and there is a retrieval wire orsuture167 secured to each apex103a-hof the left atrium flange. The right atrium flange retrieval wires or sutures are joined to a central point ornub165 and secured to aninner control wire171bof acatheter173.Central nub165 may be a crimp tube and retrieval suture or wire, as described above. The left atrium flange retrieval wires or sutures are also joined to acentral nub169 and secured to aninner control wire171a.Central nub169 may be a crimp tube and retrieval suture or wire, as described above. To deploy theprosthesis161, the medical professional positions the prosthesis in the correct position within the patient and then releases the left atrium flange, disengaging the inner control wire fromnub169, and also releases the right atrium flange, disengaging the inner control wire fromnub165.
• If retrieval is desired, the grasper or retrieval device grasps or engages bothnubs165,169, preferably separately, withinner control wires171a,171b, or with graspers attached to them, to collapse the respective flange and withdraw the prosthesis, as described below. In one embodiment, leftatrium flange legs103a-hhave a greater radius R at their root and may even approach the septum wall at an obtuse angle, i.e., as shown inFIG. 49. This larger radius will make it easier to collapse the legs and struts of the flange. Once the prosthesis is withdrawn, it may be redeployed to a better position within the patient.Prosthesis161 is capable of having both its left and right atrium flanges collapsed. If separate control wires are used, one for each flange, the flanges may be collapsed separately in time, thus requiring less force to withdraw.
• Stents for Providing Coronary Sinus Pressure Relief
• Per the discussion on heart failure, and consistent with the present disclosure, it may be beneficial for some patients to relieve pressure in the left atrium. One way to accomplish this is to provide communication between the left atrium and the coronary sinus. The coronary sinus and its tributaries receive approximately eighty-five percent of coronary venous blood. The coronary sinus empties into the posterior of the right atrium, anterior and inferior to the fossa ovalis. A tributary of the coronary sinus is called the great cardiac vein, which courses parallel to the majority of the posterior mitral valve annulus, and is superior to the posterior mitral valve annulus.
• Thus, by providing communication between the left atrium and the coronary sinus, inappropriate pressures in the left atrium can be averted, with the blood diverted to the most appropriate blood vessel possible, the coronary sinus. In cases of mitral valve failure or disease, it is possible that providing this communication could allow the patient to put off or forgo mitral valve repair. This could provide additional quality of life to the patient, while avoiding surgery that is more involved and more delicate.
• Embodiments of the stent described herein may be placed via minimally-invasive surgery, such as through endoscopic or percutaneous (vascular access) routes, or by traditional surgical methods. Minimally invasive procedures are more easily tolerated by the patients, who may also recover much more quickly from the procedure. In embodiments where the device is implanted into the atrial wall via a minimally invasive procedure, a catheter may be used, as shown generally inFIG. 50. A catheter, such as an introducer catheter is introduced through a jugular vein or a subclavian vein, through the superior vena cava (SVC), along the path of arrows A, and into the coronary sinus CS of the heart H. It is also possible to place the catheter via a femoral vein, through the inferior vena cava (IVC), along the path of arrows B, and into the coronary sinus.
• As is well known to those with skill in surgical arts, it is useful to first define the pathway via a guidewire, such as a 0.035 inch diameter (about 0.9 mm) guidewire or 0.038 inch dia. (about 1 mm) guidewire. Guidewires of other diameters may be used as needed or desired. The catheters may be maneuvered to their locations by carefully following the appropriate guidewire. It is also well known to those with skill in surgical arts that other pathways for the catheter may be used, such as through the pulmonary veins, or even through arterial pathways. If patient anatomy suffices, however, the easier method is to go through the route of the SVC as discussed above.
• FIG. 51 depicts one method of deploying the stents described herein. InFIG. 51, aguide wire10 is introduced through the jugular vein (not shown), through the superior vena cava and into the coronary sinus. Once the wire guide provides a path, anintroducer sheath12 may be routed down the guide wire and into position in the coronary sinus. The introducer sheath or introducer catheter is used to provide vascular access. The introducer sheath may be a 16F or less hemostasis introducer sheath. Alternatively, the subclavian vein may be used. In one embodiment,introducer sheath12 may be about 30 cm long. The guidewire may be somewhat longer for ease of use. In some embodiments, the introducer catheter may also function only as a dilator and an assistant for preparing an opening in the wall of the left atrium. In these embodiments, a separate placement catheter will be used. In other embodiments, the introducer catheter may be used as the placement catheter also.
• Since the coronary sinus is largely contiguous with the left atrium, there are a variety of possible acceptable placements for the stent. The site selected for placement of the stent, may be made in an area where the tissue of the particular patient is less thick or less dense, as determined beforehand by non-invasive diagnostic means, such as a CT scan or radiographic technique, such as fluoroscopy or intravascular coronary echo (IVUS).
• InFIG. 52, a bendingcatheter16 is depicted,guide wire10 is still in place but is not shown for clarity. In one embodiment, bendingcatheter16 may be about 145 cm long. A closer look at theintroducer catheter12 and the bendingcatheter16 is depicted inFIG. 53. Theintroducer catheter12, equipped with aperipheral opening13 and at least onemarker14 for radiographic or echogenic location, is shown within the coronary sinus. As noted, thewire guide10 is still in place. In one embodiment, bendingcatheter16 is about145 cm long and has a very flexible orfloppy tip18 for precisely positioning the catheter. In one embodiment, thetip18 is capable of a 90° bend so that the medical professional has very close control of its location and can easily use the catheter in the desired location. Bendingcatheter16 is also equipped with one or more echogenic orradiographic markers14 near the tip so its location may be discerned by non-invasive means, such as fluoroscopy or ultrasound techniques. Catheters with very flexible, e.g., floppy 90° distal tips, are available from Baylis Medical Company, Inc., Montreal, Canada.
• As further shown inFIG. 54, once the bendingcatheter16 and veryflexible tip18 are in the proper position, anRF wire19 will be placed into position throughcatheter16 and used to ablate the tissue and to penetrate the wall between the left atrium and the coronary sinus, which is relatively delicate tissue. Care should be taken, however, that tissue remains integral with the wall and that no loose tissue is created when the opening is made.
• For example, bipolar or monopolar radio-frequency (RF) energy may be applied to the desired area to ablate or vaporize tissues in the area to form an opening. Several techniques in this area of described in a co-pending provisional patent application assigned to the assignee of the present application and entitled “Interatrial Pressure Relief Shunt,” and filed on Feb. 10, 2011, U.S. Prov. Pat. Appl. 61/441,546, now U.S. Pat. Appl. Publ. ______, the contents of which are hereby incorporated entirely by reference and relied upon. Additional precautions may be taken in certain of these techniques, such as providing a grounding pad for the patient at least when using monopolar electrical equipment.
• Piezoelectric ultrasound techniques and piezoelectric ultrasound sensors or sensor arrays in the desired abrading area, also discussed in the above-mentioned patent document, may instead be used. Typically, DC equipment is used for RF techniques and equipment while AC equipment is used for ultrasound or piezoelectric equipment. The area in the immediate vicinity where ablating is to take place may be protected by heat transfer equipment. For example, cooling coils may be delivered by suitable catheters and placed in the area, such as in an annular ring surrounding the electrodes or sensors that deliver the ablating energy. Cooling fluids, such as saline, may be pumped through the cooling coils to counteract the very hot temperatures generated by the ablating devices. Ablative equipment is available, for example, from Baylis Medical Company, Inc., Montreal, Canada.
• In one embodiment, the opening made in the atrial wall by ablation may then be enlarged. TheRF wire19 with its flexible tip may be removed throughsheath16 and aballoon catheter20, inserted, throughsheath16 as shown inFIG. 55.Balloon catheter20 may also be equipped withmarkers14. In this technique,balloon catheter20 with tip22 and with aballoon24 is guided to the opening and the balloon is inserted into the opening between the coronary sinus and the left atrium. Usinginflation lumen26, the balloon is inflated and the opening enlarged to the desired diameter. When the opening has been made, the balloon may be deflated throughdeflation lumen28 and then removed through thesheath16. Alternatively, any suitable dilator may be used, such as a Mullins™ dilator with a needle or cutting edge or a conical distal tip of a dilator catheter. The method employed must be very reliable and very controllable by the medical professional in all stages of its deployment. The size of the opening desired may range up to about8 mm, although smaller openings may also be suitable.
• Once the opening is made between the left atrium and the coronary sinus, adeployment catheter30 is used, as depicted inFIG. 56. Similar depictions are seen inFIGS. 8-11 above, in which the prosthesis is in a compact or folded state prior to deployment. Thedeployment catheter30 may be used with aguide wire10 only or it may be used with asheath catheter12, as seen above. In the figures that follow, a sheath catheter is not shown, for simplicity, but it may be used for ease of insertion and then withdrawn before deployment of the stent. Thedeployment catheter30 includes anouter sheath32 and aninner control wire34.Outer sheath32 may also include one or more radiographic orechogenic markers36 so the sheath may be easily seen by non-invasive techniques and its location adjusted as need for proper placement.
• Deployment catheter30 also includes astent40 folded up within the catheter. As detailed below,stent40 may be in generally in a shape of a T, with a longer portion and a shorter perpendicular section. The longer portion is intended for implantation in the coronary sinus, with the perpendicular portion extending into through atrium wall into the left atrium. The stent should extend through the atrium wall, but the extension into the left atrium should be minimal, for example, only 3-4 mm. This distance is believed to insure secure implantation without extending so far as to interfere with movement of the left atrium during normal heart operation.
• Stent40 is deployed usingcontrol wire34, which extends backwards throughcatheter30 to a control device or handle (not shown) accessible to a medical professional guiding the catheter. As is well known to those with skill in the art, the catheter is deployed by holding the control wire in place while gently withdrawing theouter sheath32. As the sheath is withdrawn, the stent expands and deploys in place in the coronary sinus. As is also well known,stent40 is prepared from medically acceptable prosthesis materials, such as Nitinol, stainless steel, MP35 or other materials. Nitinol or other shape-memory alloys allow manufacturers to prepare stents and train them to assume the desired shape once they are returned to body temperature and are deployed in the body. When freed of the restraints of the confining catheter, the stent will expand and assume the shape for which it was trained.
• Stent40 is depicted in its undeployed state inFIG. 56 and in its deployed state inFIG. 57. The deployed stent is in a general form of a tube, withlonger portions41,42 intended for implantation in the coronary sinus and ashorter portion43, intended to be perpendicular tolonger portions41,42 and for extension through the orifice made in the wall of the left atrium. In the deployed state, the shortertop portion43 is intended to protrude through the orifice. In the closer view ofFIG. 57, it is seen that both portions of the stent has the appearance of about eight struts44 joined atapices45, as also shown in greater detail above inFIG. 2A. In some embodiments, the stents are not made of discrete struts but rather are laser cut or water jet cut from a thin, solid tube of Nitinol or other desired material. Thus, the stents may better be described as a network of struts and intersections of struts. In one embodiment, at least theshorter portion43, and also thelonger portions41,42 include one ormore markers46 made of a radiopaque or echogenic material. In the closer view ofFIG. 2A, note that the outer portions are smoothly rounded to avoid any trauma to the heart tissue, for example, with a radius of curvature greater than 0.03 inches (about 0.8 mm).
• The stent thus implanted should be capable of two important tasks. The stent should be sized so that the longer part,portions41,42 remain in place within the coronary sinus without movement. Accordingly, the diameter of these portions should be in the range of about 8-13 mm, perhaps in the range of 8-11 mm, because the posterior portion of the coronary sinus, in the desired location, is a little smaller than the anterior portion. With the longer portion of the stent fixed in place, the shorter portion, orcrown portion43, will also remain in place.
• Once placed, the crown also will not move and will be in a position to keep the orifice open between the left atrium and the coronary sinus. Accordingly, it should not be necessary for the upper portion to exert much force on the opening, and it will be desirable for this portion to be flexible and atraumatic rather than stiff. The coronary sinus is very sensitive to abrasion and the stent portions that reside in the coronary sinus need to be atraumatic while the LA legs need to conform to the curvage or the radius of the opening into the left artrium chamber. At the same time the transverse or crown portion of the stent needs to be strong enough to keep the freshly made opening between the coronary sinus and the left atrium from closing; this would defeat the purpose of the prosthesis. In other embodiments, described below, the upper portion may form a flange, with longer or shorter extensions along the longitudinal direction of the stent, as shown inFIGS. 58 and 59.
• InFIG. 58,stent50 includes a top portion or flange51 with about 4 protruding triangular struts53. The radius of curvature is relatively tight, from about 5 mm to 15 mm, so that the flange is not held tightly by the atrial wall in the vicinity of the flange. The flange in this embodiment extends about 2-4 mm in a direction parallel to the coronary sinus. InFIG. 59,stent56 includes a top portion orflange57 with about 6 (not all are shown) protruding struts58. The radius ofcurvature59 here is somewhat looser, from about 10 mm to about 40 mm. In one embodiment, the flange extends only about 1-2 mm in a direction parallel to the coronary sinus.
• One aspect of the stents for enabling communication between the left atrium and the coronary sinus is that it may be desirable to have only one-way communication. One embodiment of the stent is designed to allow pressure relief of the left atrium by providing an outlet to the coronary sinus without allowing retrograde flow. The coronary sinus directs blood flow from several veins, such as the small, middle, great and oblique cardiac veins, the left marginal vein and the left posterior ventricular vein. It is not desirable, however, to allow flow from the coronary sinus into the left atrium. The stent may thus be restricted to one-way flow by providing the stent with a flow control element of the type disclosed elsewhere herein.
• FIGS. 60 and 61 depict two embodiments of a stent limited to one way communication by a restricting valve. InFIG. 60,stent60 includes atop portion61 intended for deployment above the wall between the left atrium and the coronary sinus.Stent60 also includes atransverse portion67 intended for deployment within the coronary sinus as described above.Top portion61 in this embodiment includes amulti-part flap valve63 secured to thetop portion62 oftower61 withsutures64. While theflap valve63 in this embodiment has two portions a bi-valve, that meet roughly along a diameter of the top portion, other embodiments may have three or more portions, again, meeting in the middle. It is also possible to have a single flap, tethered perhaps along one side by about 30-45 degrees of the circumference. This embodiment also includes one ormore stops65 to prevent the valve from opening in the other direction and allowing blood to flow from the coronary sinus into the left atrium. The flow control element could also be a ball and socket valve, a duckbill valve, a butterfly valve, or any other valve component known to those skilled in the art or as those disclosed in the commonly-owned application mentioned above.
• As is well known to those with skill in cardiac arts, the valve or flap may be made of mammalian pericardium, such as bovine pericardial tissue, or from ovine or porcine pericardial tissue. Other suitable tissue may also be used. In one embodiment, the tissue is about 0.5 to about 1 mm thick. Other thicknesses may be used. The valve and the flaps are designed so that blood will flow through the one-way valve when the pressure differential reaches about 5-10 mm Hg.
• FIG. 61 depicts another embodiment of a one-way valve useful in the stents disclosed herein. In this exploded view,valve70 is formed within the top portion71 of a coronary sinus pressure relieving stent. The valve includes aplate75 withmultiple perforations76. Whileperforations76 are shown as slots, they may be made of any suitable shape. The plate itself made may be made of any material suitable for in vivo contact with blood, including inert polymers such as polycarbonate or polysulfone, or metals such as stainless steels, MP35N or Nitinol. As shown, perforatedplate75 is adjacent the distal end of the stent top portion71. On the opposite side of theperforated plate75 is avalve element73 withflaps74. In one embodiment, flaps74 are slightly larger that the gaps beneath the flaps, enabling the flaps to seal tightly if for some reason the pressure in the coronary sinus exceeds the pressure in the left atrium, on the far side of the stent.
• During normal operation, when the pressure in the left atrium exceeds the pressure in the coronary sinus, blood will tend to flow from the left atrium through the stent, and in particular at the outset, through thetop portion70. Blood will flow through theperforated plate75 and since theflaps74 are free to flap downward, in the embodiment ofFIG. 61, the blood will flow throughvalve element73 and on into the coronary sinus. However, theflaps74 are not free to flow in the opposite direction, toward the left atrium, because their movement is prevented by theperforated plate75. Other embodiments of check valves or one-way valves may also be used.
• Other embodiments of stents for relieving pressure may have other configurations. For example,FIG. 62A depicts a T-tube stent in a before-deployment configuration.Stent80 includes alonger portion81 in a general shape of a cylinder for placement in a coronary sinus of a patient. The stent is constructed ofshort struts84 andapices86 joining the struts, or as mentioned above, an interconnecting network of struts and joining areas. A shorter portion,tower82 is folded within thelonger portion81. Upon deployment of the stent within a patient, the longer portion will expand if the stent has been trained to do so when the austenitic transition occurs upon warming to body temperature. Thetower portion82 may then be deployed from its refracted position within the longer portion to its deployed position, as shown inFIG. 62B.
• The tower will assume its intended shape as it is deployed and as it warms to body temperature. The tower includes a wider portion, i.e., a portion with a larger diameter that will reside within the left atrium. The tower also includes anarrower portion83 having a diameter about the diameter of the opening which was prepared for the stent.Tower portion82 may be pushed into place, for example, by a balloon catheter if it fails to deploy properly by the “memory metal” effect. While the principal portion of the stent is constructed of struts and apices, in this embodiment, the tower may be made from many more flexible,thinner wires88 for greater ease of deployment. In one embodiment, the wires are 0.003 in (0.08 mm) diameter and are thus very flexible. The wires form a porous closed “net” whose openings allow blood to flow from the left atrium to the coronary sinus.
• While the invention has been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law.
• The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
• While embodiments have been disclosed and described in detail, it is understood that various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present disclosure is not limited by the foregoing examples, but is better understood by the claims below.

Claims (22)

1. A stent for use in a patient, comprising:

a plurality of struts; and

a plurality of intersections joining the struts to form a stent having a longer cylindrical portion and a shorter cylindrical portion adjacent the longer cylindrical portion and extending beyond the longer cylindrical portion in a direction perpendicular to an axis of the longer cylindrical portion,

wherein the longer cylindrical portion is adapted to fit into and bear against a coronary sinus and wherein the shorter portion is adapted to form an opening from the coronary sinus to a left atrium of the patient.

2. The stent according toclaim 1, wherein the struts are made from a metal selected from the group consisting of shape memory alloys, nitinol, stainless steel and MP35.

3. The stent according toclaim 1, wherein the stent further comprises at least two features with properties selected from the group consisting of radiographic properties and echogenic properties.

4. The stent according toclaim 1, further comprising at least one flap attached to the shorter portion, the flap attached and oriented to allow blood to flow only one way, from the left atrium into the coronary sinus.

5. The stent according toclaim 1, further comprising at least one flap made from mammalian pericardium attached to the shorter portion, the flap attached and oriented to allow blood to flow only one way, from the left atrium into the coronary sinus.

6. The stent according toclaim 1, further comprising a flange on the shorter portion for engaging an atrial wall of the patient.

7. The stent according toclaim 1, further comprising a segmented flange on the shorter portion for engaging an atrial wall of the patient.

8. A stent for use in a patient, comprising:

a longer, radially-expanding portion adapted for placement in a coronary sinus of the patient; and

a shorter portion adjacent and joined to the longer, radially-expanding portion, the shorter portion extending beyond the longer, radially-expanding portion in a direction perpendicular to an axis of the longer radially-expanding portion, the shorter portion adapted for placement within a left atrium of the patient,

wherein the longer, radially-expanding portion is adapted to bear against a wall of the coronary sinus and wherein the shorter portion is adapted to form an opening between the left atrium and the coronary sinus of the patient.

9. The stent ofclaim 8, wherein the longer or shorter portion comprises radiopaque or echogenic features.

10. The stent ofclaim 8, wherein the shorter portion is formed from a plurality of struts and intersections joining the struts, and further comprising at least one flap attached to the shorter portion, the flap attached and oriented to allow blood to flow only one way, from the left atrium into the coronary sinus.

11. The stent ofclaim 10, wherein the at least one flap is attached and oriented so that blood flows from the left atrium into the coronary sinus when a pressure difference across the at least one flap reaches at least 1-10 mm Hg.

12. The stent ofclaim 8, wherein the shorter portion is more flexible than the longer portion.

13. A method for relieving intracardial pressure, the method comprising:

providing an opening between a left atrium of a heart and a coronary sinus; and

allowing blood to flow from the left atrium into the coronary sinus, thus relieving pressure.

14. The method ofclaim 13, further comprising providing a stent and implanting the stent in the opening between the left atrium and the coronary sinus.

15. A method for relieving intracardial pressure, the method comprising:

furnishing a stent suitable for implantation into a coronary sinus of a patient, the stent suitable for extending from the coronary sinus to within a left atrium of the patient and for maintaining communication between the left atrium and the coronary sinus;

preparing an opening into the left atrium using at least one instrument in the coronary sinus;

maneuvering the stent into the coronary sinus to a position near the opening; and

deploying a portion of the stent into the opening, wherein the stent maintains communication between the left atrium and the coronary sinus to relieve pressure within the left atrium.

16. The method according toclaim 15, wherein the step of preparing the opening further comprises:

guiding a first catheter into the coronary sinus of the patient, the first catheter including a side port and also including a cutting or ablating instrument for creating the opening into the left atrium.

17. The method according toclaim 15, further comprising expanding the opening using a balloon catheter.

18. The method according toclaim 15, wherein the step of maneuvering the stent comprises:

guiding the stent into the coronary sinus with a catheter; and

placing the stent into the opening by withdrawing an outer sheath from around the stent.

19. A method for relieving intracardial pressure, the method comprising:

furnishing a stent suitable for implantation into coronary sinus of a patient, the stent suitable for extending from the coronary sinus to within a left atrium of the patient and for maintaining communication between the left atrium and the coronary sinus;

preparing an opening in a wall between the left atrium and the coronary sinus;

maneuvering the stent to a position near the opening; and

deploying the stent into the opening, wherein the stent maintains communication between the left atrium and the coronary sinus.

20. The method ofclaim 19, wherein the opening in the wall is prepared using an ablative catheter in the coronary sinus to create the opening and a balloon catheter in the coronary sinus to expand the opening to a desired dimension.

21. The method ofclaim 19, further comprising engaging a wall of the atrium with a flange of the stent.

22. The method ofclaim 19, further comprising engaging an inner surface of the coronary sinus using a close fit between the stent and the coronary sinus.

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