Mitral valve placement device, system, and methodThe application is a divisional application based on the divisional application with the application number of 201711162783.3. The original application has application number 201380016557.8(PCT/IB2013/000593), application date 1, 31, 2013 and is named as a mitral valve parking device, system and method.
Cross Reference to Related Applications
This application claims priority to the following U.S. provisional applications: united states provisional application serial No. 61/796,964 (pending) filed on 26.11/2012; U.S. provisional application serial No. 61/744,468 (pending) filed on 27.9.2012; U.S. provisional application serial No. 61/687,898 (pending) filed on 3/5/2012; U.S. provisional application serial No. 61/592,796 (pending) filed on 31/1/2012; the disclosure of the above application is hereby incorporated by reference.
Technical Field
The present invention relates generally to medical instruments and devices related to heart valves, such as replacement techniques and devices. More particularly, the present invention relates to replacement of heart valves having various malformations and dysfunctions.
Background
Complications of the mitral valve, which controls blood flow from the left atrium to the left ventricle of the human heart, are known to cause fatal heart failure. In developed countries, one of the most common forms of valvular heart disease is mitral valve leakage, also known as mitral regurgitation, which is characterized by abnormal leakage of blood from the left ventricle through the mitral valve and back into the left atrium. The most common causes of this occurrence when the leaflets of the mitral valve no longer properly contact or close after multiple infarcts, idiopathic and hypertensive cardiomyopathy are ischemic heart disease, in which the left ventricle is enlarged and the leaflets and chordae tendineae are abnormal, such as those caused by degenerative disease.
In addition to mitral regurgitation, the most frequent cause of mitral valve narrowing or stenosis is rheumatic disease. Although this disease has in fact been eliminated in developed countries, it is still common in places where the standard of living is not high.
A complication similar to that of the mitral valve is that of the aortic valve, which controls the flow of blood from the left ventricle into the aorta. For example, many elderly patients suffer from aortic valve stenosis. Historically, the traditional treatment has been valve replacement performed by large open-heart surgery. The procedure, because it is so highly invasive, requires a considerable amount of time to recover. Fortunately, great progress has been made over the past decade in replacing this open heart surgery with catheter surgery, which can be performed quickly without surgical incisions, or without a heart-lung machine that supports circulation while the heart is stopped. Using a catheter, the valve is mounted on a stent or stent-like structure, which is compressed and delivered to the heart through a blood vessel. The stent then expands and the valve comes into play. The diseased valve is not removed, but rather is crushed or deformed by the stent containing the new valve. The deformed tissue is used to help anchor the new prosthetic valve.
Valve delivery can be accomplished from an artery, allowing easy access to the artery in the patient. Most commonly this is done from the groin where the femoral and iliac arteries can be catheterized. The shoulder area may also be utilized, where the subclavian and axillary arteries may also be accessed. Recovery from this procedure is very rapid.
Not all patients may employ pure catheter procedures. In some cases, the arteries are too small to allow the catheter to pass through to the heart or the arterial lesions are severely or excessively tortuous. In these cases, the surgeon may make a small chest incision (thoracotomy) and then place these catheter-based devices directly into the heart. Typically, a purse string suture is made in the apex of the left ventricle and the delivery system is placed through the apex of the heart. The valve is then delivered into its final position. These delivery systems may also be used to access the aortic valve from the aorta itself. Some surgeons introduce the aortic valve delivery system directly into the aorta at the time of open-view surgery. The valve can vary significantly. There is a mounting structure, typically in the form of a bracket. The prosthetic leaflet is carried inside the stent on the mounting and retaining structure. Typically, these leaflets are made of a biomaterial used in conventional surgical valves. The valve may be real heart valve tissue taken from animals or more generally the leaflets are made from pericardial tissue taken from cattle, pigs or horses. These leaflets are treated to reduce their immunogenicity and improve their durability. A number of tissue processing techniques have been developed for this purpose. In the future, bioengineered tissue, or polymers or other non-biological materials may be used for the valve leaflets. All of which can be incorporated into the invention described in this disclosure.
In fact, more patients suffer from mitral valve lesions than aortic valve lesions. Over the course of the past decade, many companies have successfully prepared catheter or minimally invasive implantable aortic valves, but implantation of the mitral valve is more difficult and has not been a good solution to date. Patients benefit from implanting the device by surgery with a small incision or by catheter implantation, such as from the groin. Catheter procedures are very attractive from a patient's point of view. There is no commercially available method for replacing the mitral valve with a catheter procedure. Many patients requiring mitral valve replacement are elderly and open heart surgery is painful, risky and requires some time for recovery. Some patients are elderly and weak or even advised not to undergo surgery. Thus, there is a particular need for a remotely placed mitral valve replacement device.
While it has also been previously thought that mitral valve replacement, rather than valve repair, is associated with more negative long-term prognosis for patients with mitral valve disease, this belief has been questioned. It is now believed that the results are nearly the same for patients with mitral valve leakage or regurgitation, whether the valve is repaired or replaced. In addition, the durability of surgical repair of the mitral valve is now under question. Many patients receiving repair suffer a leak again after several years. Since many of these patients are elderly, repeated interventions in elderly patients are not welcomed by the patient or the physician.
The most significant obstacle to catheter mitral valve replacement is to hold the valve in place. The mitral valve is subjected to large cyclic loads. The pressure in the left ventricle approaches zero before contraction and then rises to the systolic pressure (or higher if there is aortic stenosis), which can be very high if the patient has systolic hypertension. The load on the valve is typically 150mmHg or more. Since the heart is moving as it beats, the motion and load can combine to cause the valve to shift. Furthermore, motion and rhythmic loading can fatigue the material, causing it to crack. Thus, there is a significant problem associated with anchoring valves.
Another problem with mitral valve replacement with catheter delivery is size. The implant must have strong retention and leakage avoidance characteristics and it must include a valve. A separate prosthesis may help to address this problem by first placing the anchor or dock and then implanting the valve. In this case, however, the patient must remain stable between the implantation of the anchor or dock and the implantation of the valve. If the native mitral valve of the patient fails due to the anchor or the dock, the patient can quickly become unstable, and the operator may be forced to rush to implant a new valve or may stabilize the patient by removing the anchor or dock and abandoning the procedure.
Another problem with mitral valve replacement is paravalvular or paravalvular leakage. If a good seal is not established around the valve, blood may leak back into the left atrium. This adds extra load to the heart and can damage the blood as it travels through the leak site in a jet stream. If this occurs, hemolysis or rupture of the red blood cells is a common complication. Paravalvular leakage is one of the common problems encountered when an aortic valve is first implanted on a catheter. During surgical replacement, the surgeon has great advantage when he or she replaces the valve with visibility of the space outside the valve sutures and prevention or repair thereof. This is not possible for catheterization. In addition, larger leaks can reduce patient survival and can lead to symptoms that limit mobility and cause patient discomfort (e.g., shortness of breath, edema, fatigue). Thus, the devices, systems and methods associated with mitral valve replacement should also incorporate means to prevent paravalvular leakage and repair it.
The mitral valve annulus (mitral valve annulus) of a patient can also be very large. When companies develop surgical replacement valves, this problem is addressed by limiting the number of actual valve sizes that are prepared, and then adding more fabric sleeves around the edges of the valve to increase the size of the valve. For example, a patient may have a 45 mm annulus. In this case, the diameter of the actual prosthetic valve may be 30 millimeters, and the difference is compensated for by adding a larger strip of fabric cover material around the prosthetic valve. However, in the operation of catheters, adding more material to the prosthetic valve is problematic because the material must be compressed and held by a small delivery system. Often this approach is difficult and impractical, so alternative solutions are necessary.
As many valves have been developed that are suitable for aortic placement, it is desirable to avoid repeated valve development and take advantage of existing valves. These valves are very expensive to develop and market, so expanding their application can save considerable amounts of time and money. It would then be beneficial to form a mitral anchor or dock suitable for such a valve. Existing valves, perhaps with some variations, developed for aortic locations may then be implanted into the dock. Some previously developed valves fit well without modification, such as Edwards SapienTMAnd (4) a valve. Others such as CorevalveTMMay also be implanted, but some variation is needed to optimally engage and fit the anchor inside the heart.
The inadequate retention or positioning of the mitral valve replacement prosthesis can cause a number of additional complications. That is, the valve may become dislodged into the atrium or ventricle, which can be fatal to the patient. Previous prosthetic anchors have reduced the risk of displacement by piercing tissue to hold the prosthesis. However, this is a risky strategy, since the penetration must be done by a sharp object at a long distance, leading to a risk of perforation of the heart and injury to the patient.
The orientation of the mitral valve prosthesis is also important. The valve must allow blood to flow easily from the atrium into the ventricle. Prostheses that enter at an angle can result in poor flow, obstruction of flow by the heart wall or leaflets, and poor hemodynamic results. Repeated contractions against the ventricular wall can also lead to rupture of the posterior wall of the heart and to sudden death of the patient.
By surgically repairing or replacing the mitral valve, sometimes the anterior leaflet of the mitral valve leaflet is pushed into the area of the left ventricular outflow tract, which can result in poor left ventricular drainage. This syndrome is known as left ventricular outflow obstruction. Valve replacement itself can cause obstruction of the left ventricular outflow tract if it is positioned close to the aortic valve.
Yet another obstacle faced when implanting a replacement mitral valve is the need for the patient's native mitral valve to continue to function regularly during prosthesis placement so that the patient can remain stable without the need to support a circulatory heart-lung machine.
In addition, it is desirable to provide devices and methods that can be used in a variety of implantation approaches. Depending on the anatomy and clinical situation of a particular patient, it may be desirable for a medical professional to make decisions regarding the optimal method of implantation, such as inserting a replacement valve directly into the heart in open-heart surgery (open-heart surgery or minimally invasive surgery) or from veins and via arteries in closed-type surgery (such as catheter-based implantation). Preferably a plurality of implant options that allow a medical professional to select from. For example, a medical professional may wish to insert a replacement valve from the ventricular or atrial side of the mitral valve.
Accordingly, the present invention provides devices and methods that address these and other challenges in the art.
Disclosure of Invention
The present invention provides a dock that is stable and capable of holding a mitral valve replacement prosthesis to control the flow of blood from the left atrium into the left ventricle. Other devices and methods are also provided that improve the positioning of such combinations in non-invasive or minimally invasive surgery. Additional devices and methods are also provided to further prevent regurgitation or blood leakage, such as through the commissures of the native mitral valve (comisure) or around the outer surface of the replacement valve prosthesis.
In one aspect, the present invention provides a system for parking a mitral valve prosthesis. The system includes a coiled guide catheter and a helical anchor. The coil guide catheter includes a shaft portion and a distal end portion connected to the shaft portion at a first curved portion. The distal portion includes a second curved portion configured to generally follow the curvature of the mitral annulus. The helical anchor is adapted to be received within and extruded or otherwise delivered from the coil guide catheter. The helical anchor is formed as a multiple coil (coil) having a pre-formed coil configuration after being extruded from the coil guide catheter. Alternatively, the helical anchor may be delivered from the coil guide catheter in other ways, but the compression allows the coil to be gradually and accurately placed into the proper and desired position relative to the native mitral valve. Furthermore, if the operator is not satisfied with the obtained positioning, the helical anchor can be moved back into the coil guide catheter and the implantation process can be started again. The helical anchor is adapted to support the prosthetic mitral valve when fully extruded or delivered from the coiled guide catheter and implanted with the coiled portion above and below the mitral annulus. The system further may include various components. A prosthetic valve is provided and is capable of being delivered into a mitral valve location of a patient and expanded inside the multiple coils and into engagement with leaflets of the mitral valve. The prosthetic valve can include a slot configured to engage with the multiple coils to couple the prosthetic valve with the helical anchor. The helical anchor can further include a shape memory material. The multiple coils may comprise an end coiled portion, such as a tail-like extension, formed as a coil of increased diameter relative to the next adjacent coil. The extension may take other forms as well. The coils of the helical anchor can take many different shapes and forms, some of which are shown herein. The coils may be in separate planes, such as coil springs, or some or all of the coils may be at least initially in substantially the same plane prior to implantation. The end coiled portion is configured to engage a left atrial wall of the heart when the multiple coils have been fully delivered from the coil guide catheter and the coiled portions are positioned above and below the mitral annulus.
The system may further include a plurality of anchor arms coupled with the helical anchor and configured to engage the mitral valve leaflet. The anchor arms may have various configurations, such as hook-shaped members. A control element may be provided in the system and include a connecting element configured to couple, directly or indirectly, with the helical anchor so as to guide placement of the helical anchor relative to the mitral valve. The control element may take a variety of forms, such as a snare catheter or a catheter including a grasping tool, or a simple cable or suture, or the like. The helical anchor can further include an engagement element configured to allow the connection element to be coupled thereto. The engagement element may also take various forms, such as an enlarged tip or end of a helical anchor.
The system may further include a positioning screw configured to be extruded or otherwise delivered from the coiled guide catheter to assist in positioning the helical anchor. The extension may be coupled with the second curved portion of the coil guide catheter and configured to aid in positioning the second curved portion on top of the mitral valve when delivering the helical anchor. The extension may include various forms, such as including a flat membrane for engaging the top of the mitral valve. The system further can include an anchor delivery catheter and an anchor. For example, an anchor delivery catheter is coupled with a coil guide catheter and/or a helical anchor to deliver the anchor into tissue at the mitral valve location. For example, multiple anchors may be delivered to close the gap at the annulus tissue plication and/or native mitral valve commissure.
The helical anchor may comprise, for example, a solid wire or a hollow wire configured to be delivered over a guidewire.
In another exemplary embodiment, the present invention provides an apparatus for parking a mitral valve prosthesis that includes an expandable stent and a plurality of anchor arms. The expandable stent is configured to be delivered from a catheter to a mitral valve location of a patient and then expanded. The expandable stent includes an upper end and a lower end. A plurality of anchor arms are coupled with the lower end and configured to engage the mitral valve leaflets. The anchor arms may include various configurations, such as hook-like members. In various embodiments, other configurations of the hook-like members or anchoring arms may change in size as the stent expands. The expandable stent further may include an expandable atrial portion and an expandable valve-retaining portion. The expandable atrial portion is configured to engage the left atrial wall when expanded at the mitral valve location in the heart. The valve retaining portion is adapted to engage the mitral valve leaflets. The anchoring arms are coupled with the valve retaining portion.
The present invention also provides various methods associated with the placement of a mitral valve at a mitral position in a heart and additional devices, systems, and components for performing such methods. For example, various methods and systems allow for a catheter-based percutaneous procedure that does not require the operator to rotate the catheter, but rather allows the operator to implant a prosthetic mitral valve anchor or parking device using easier pushing and/or pulling motions. The leading tip of the multiple coiled helical anchor may be directed from the coiled guide catheter to the opposite side of the native mitral valve. A control element, such as a snare catheter or a catheter with a gripping element, may be used to assist in positioning the helical anchor during delivery to the mitral valve location. Another approach involves the placement of multiple coiled helical anchors such that one portion of the helical anchor is positioned below the native mitral valve and another portion is placed above the native mitral valve but not in contact with the valve tissue, but merely engages against the atrial tissue. The lower portion of the helical anchor may engage against and press against the native mitral valve leaflets. The helical anchor may have coils of various diameters, and one or more segments of the coil may be configured to dock or engage against the atrial wall in order to stabilize the helical anchor, and ultimately the prosthetic mitral valve.
In a more specific aspect, for example, the present invention provides a method of implanting a mitral valve prosthesis in a heart of a patient, including guiding a coiled guide catheter to a mitral valve location in the heart of the patient. A pre-shaped curved portion approximately in the mitral valve plane is placed in the left atrium, wherein the curvature of the pre-shaped curved portion approximately follows the curvature of the mitral annulus. The pre-shaped curved portion may assume its curved shape as it is extruded or extended from the coiled guide catheter, or be activated to the pre-shaped curved shape as or after it is inserted into position at the mitral valve location. The helical anchor is delivered from the coil guide catheter in multiple coils such that a portion of the helical anchor is above the native mitral valve and a portion is below the mitral valve. The mitral valve prosthesis is implanted within the multiple coils of the helical anchor such that the mitral valve prosthesis is supported by the helical anchor.
In further aspects, for example, an introducer is introduced through the heart tissue and a coiled guide catheter is introduced through the introducer to the mitral valve location. Alternatively, the method may be performed percutaneously by guiding the coil guide catheter through the patient's venous system to the mitral valve location. A control element may be used to guide the helical anchor into a desired position relative to the native mitral valve. The control element may take any suitable form, such as any element suitably coupled (directly or indirectly) with a portion of the helical anchor. For example, the control element may be coupled directly to the helical anchor, such as by a grasping tool or suture, or the control element may be coupled with a coil guide catheter. The control element is used to push and/or pull the helical anchor into position relative to the native mitral valve. The tip of the helical anchor may be squeezed or otherwise delivered between and over the leaflets of the native mitral valve at one of the commissures, and then further directed into the patient's left ventricle below the mitral valve. Alternatively, the tip of the helical anchor may be delivered initially into the left ventricle and subsequently into the left atrium, such as by guiding it between the leaflets. The fabric may be placed between the mitral valve prosthesis and a portion of the helical anchor. A guidewire may be used for reference purposes. For example, a guidewire may be placed through the aortic valve and into the aorta. The guidewire can then be used as a reference to aid in the positioning of the helical anchor.
In further aspects, the tissue anchor delivery catheter can be guided to the mitral valve location using a helical anchor and/or a coiled guide catheter. A tissue anchor delivery catheter is used to deliver a first tissue anchor into tissue at a mitral valve location. A second tissue anchor may then be delivered into the tissue at the mitral valve location, and the first and second tissue anchors may then be secured together to plicating or approximating the tissue.
The mitral valve prosthesis is delivered to a location within the helical anchor, and the mitral valve prosthesis is initially in an unexpanded state during delivery through a suitable catheter. The mitral valve prosthesis is then expanded such that the mitral valve prosthesis is supported by the multiple coils. When the mitral valve prosthesis is expanded, the prosthesis expands against the native mitral valve leaflets, and the leaflets are secured between the prosthesis and a ventricular coil or other anchoring structure so that the leaflets are securely fixed. This serves to prevent occlusion of the aortic valve by the anterior leaflet in addition to providing prosthetic support for the valve.
In another common approach, a mitral valve prosthesis is implanted in a patient's heart by guiding a stent delivery catheter to the mitral valve location in the patient's heart. The stent dock extends from the stent delivery catheter. The atrial portion of the stent dock is expanded within the left atrium such that the atrial portion engages the left atrial wall. The valve-retaining portion of the stent dock expands against the native mitral valve leaflets. The mitral valve prosthesis is implanted within the valve-retaining portion such that the mitral valve prosthesis is supported by the stent dock.
In further aspects, various helical anchors are provided in desired embodiments for parking the mitral valve prosthesis. In one embodiment, the anchor includes a plurality of coils having a pre-shaped coiled configuration after delivery from the coil guide catheter and adapted to support the prosthetic mitral valve when fully delivered from the coil guide catheter and implanted with respective coiled portions above and below the mitral annulus. In one aspect, the helical anchor includes a distal portion formed to extend downwardly and radially outwardly relative to a next adjacent coil such that the distal portion is spaced apart from the next adjacent coil and configured to be delivered between native mitral valve commissures.
In another aspect, the helical anchor includes an upper atrial coil adapted to be placed above the native mitral annulus and a lower ventricular coil adapted to be placed below the mitral annulus. The upper coil is adjacent to the lower coil and forms a gap between the upper and lower coils, creating a space that exists prior to implantation of the coils, such that the upper and lower coils do not capture mitral leaflet tissue when implanted. This may allow, for example, native mitral valve tissue to naturally close at the annulus and prevent blood leakage at those locations. The upper coil may have a larger diameter than the lower coil, thereby engaging the atrial wall of the heart when implanted.
In another aspect, the plurality of coils includes an upper atrial coil adapted to be placed above the native mitral annulus and a lower ventricular coil adapted to be placed below the native mitral annulus. In this aspect, the extension extends out of the plane of the upper coil and is spaced from the upper coil so as to engage the atrial wall and provide stability when implanted within the heart.
In another aspect, the plurality of coils comprises a plurality of upper atrial coils and a plurality of lower ventricular coils. The upper atrial coil is adapted for placement over the native mitral annulus and extends upwardly to adjustably position the mitral valve prosthesis at a desired height relative to the mitral annulus. This may allow the operator to position the mitral valve prosthesis at an elevation, for example, so as not to impede blood flow from the ventricle through the aortic valve. The plurality of lower ventricular coils may be configured to receive mitral valve leaflets therein and also prevent occlusion of the aortic valve by the mitral valve anterior leaflet.
Various additional advantages, methods, devices, systems, and features will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings.
Drawings
Fig. 1A-1F illustrate in perspective view placement of one embodiment of a helical anchor in a mitral valve location of a heart, the mitral valve being shown in partial cross-section.
Fig. 1G is a cross-sectional view of the helical anchor shown in fig. 1F.
Fig. 1H is a cross-sectional view of a valve prosthesis retained by the helical anchor shown in fig. 1F and 1G.
Fig. 1I is a cross-sectional view of an alternative embodiment of a helical anchor that has been placed in the mitral position of the heart, with the coil in the atrium not contacting the valve leaflets, but with the anchor against the atrial wall.
Fig. 1J is a cross-sectional view of a valve prosthesis held by the helical anchor shown in fig. 1I.
Fig. 1K is a cross-sectional view of a valve prosthesis retained by another alternative embodiment of a helical anchor, wherein the helical anchor has been placed within a mitral valve location of the heart.
Fig. 2 is a perspective view of another alternative helical anchor for a mitral valve prosthesis, featuring an initial region extending outwardly from the coil.
Fig. 3 is a side view of the helical anchor shown in fig. 2.
Fig. 4 is a bottom view of the helical anchor shown in fig. 2 and 3.
Fig. 5 is a top view of a helical anchor placed into a heart mitral valve location via a commissure within a native mitral valve.
Fig. 6 is a perspective view of another alternative helical anchor of a mitral valve prosthesis, featuring no taper at the beginning but a slight outward bend (turn).
Fig. 7 is a perspective view of another alternative helical anchor having a wider tail portion or extension capable of engaging the atrial wall.
Fig. 8 is a perspective view of another alternative helical anchor having a tail portion or extension that is substantially wider than the tail portion shown in fig. 7, shown positioned within a mitral valve location of the heart.
Fig. 9A-9C illustrate in perspective an alternative helical anchor having anchor arms and expanding from a compressed state within a sheath to a deployed state.
Fig. 10A is a perspective view of the helical anchor shown in fig. 9A, retained within a sheath and placed within a mitral valve location of a heart, the mitral valve of the heart being shown in partial cross-section.
Fig. 10B is a cross-sectional view of the helical anchor of fig. 9A-10A positioned within a mitral valve location of a heart showing the anchor arms engaged with the valve leaflets.
Fig. 10C is a cross-sectional view of a valve prosthesis retained by the helical anchor shown in fig. 9A-10C.
Fig. 11A-11C are side views of the helical anchor of fig. 9A-9C showing the anchor arms expanded from a compressed state to a deployed state (with most of the anchor arms removed for clarity).
Fig. 12A is a side view of an embodiment of a stent dock having hooks that are raised as the stent dock expands and contracts.
Fig. 12B is a side view of another embodiment of a stent parking portion having dual wire hook portions that are lifted as the stent parking portion expands and contracts.
Fig. 13A and 13B are side views of a hook distributed along a serpentine wire that lifts upward as the serpentine wire is straightened and which can be incorporated into a stent dock.
Fig. 14A and 14B are side views of a serpentine wire mounted on a center retaining wire and a hook distributed along the serpentine wire that lifts upward as the serpentine wire is straightened and which can be incorporated into a helical anchor.
Fig. 14C and 14D are cross-sectional views of a hook formed on a wire placed within a sheath and lifted upward as the wire is pulled through the sheath.
Figures 15A-15E illustrate, in perspective view, placement of one embodiment of a stent dock in a mitral valve position of a heart, the mitral valve being shown in partial cross-section.
Fig. 15F is a cross-sectional view of the stent dock of fig. 15E as it engages the valve leaflets and the atrial wall.
Fig. 15G is a cross-sectional view of the valve prosthesis held by the stent dock shown in fig. 15F.
Fig. 16A and 16B illustrate in perspective view a stent dock having an atrial assembly transitioning from a closed state to an open state.
Fig. 16C is a perspective view of the stent dock of fig. 16A and 16B when the valve retaining portion is expanded and the hook portions are deployed.
Figure 16D is a cross-sectional view of the fully deployed stent dock of figures 16A-16C with the valve holder partially deployed.
Fig. 17A-17D illustrate in perspective an alternative procedure for placement of a helical anchor within a mitral valve location of a heart by way of a venous system, shown in cross-section.
Fig. 18A-18C illustrate in perspective view another alternative procedure for placement of a helical anchor within a mitral valve location of a heart by way of a venous system, shown in cross-section.
Figures 19A-19D illustrate in perspective an alternative procedure for placement of a stent dock in a mitral valve location of the heart by way of a venous system, shown in cross-section.
Fig. 19E is a cross-sectional view of an alternative embodiment of the invention with the valve prosthesis integrated into the valve-retaining portion of the stent dock and placed into position with the mitral valve of the heart shown in partial cross-section.
Fig. 20 illustrates, in perspective view, placement of an embodiment of a helical anchor within a mitral heart valve location, the mitral heart valve shown in partial cross-section, with the helical portion of the anchor deployed and the anchor loop retained within the sheath.
Fig. 21 is a close-up view of the helical anchor of fig. 20 positioned within a mitral valve location of a heart, the mitral valve being shown in partial cross-section, with the sheath retracted to deploy the helical portion within the atrium and the anchoring loop within the ventricle.
Fig. 22 is a cross-sectional view of a valve prosthesis retained by the helical anchor of fig. 20-21 by means of a sheath.
Fig. 23A-23D illustrate in perspective view placement of a helical anchor embodiment in a mitral valve position of the heart, the mitral valve being shown in partial cross-section, the helical anchor being placed in the mitral valve position of the heart by means of a guidewire placed in the right atrium and a positioning screw placed in the left atrium via the left ventricle.
Fig. 24A-24C show, in perspective, placement of a helical anchor embodiment in a mitral heart valve location, shown in cross-section, the helical anchor being placed in the mitral heart valve location by means of a positioning screw placed in the left atrium via a transseptal delivery device.
Fig. 25A-25C show in perspective the placement of a helical anchor embodiment in a cardiac mitral valve location, shown in partial cross-section, the helical anchor being placed in the cardiac mitral valve location by means of a pull band to pull a coiled delivery catheter or a coiled guide catheter under leaflets of the native mitral valve.
Fig. 26A-26C show in perspective the placement of a helical anchor embodiment in a mitral valve position of the heart, shown in partial cross-section, with the helical anchor placed in the mitral valve position of the heart by means of a snare to pull the helical anchor under the leaflets of the native mitral valve.
Figure 27A is a close-up view of the coiled delivery catheter or coiled guide catheter shown in figures 26A-26C.
Figure 27B illustrates the coiled delivery catheter or coiled guide catheter of figure 27A having a downwardly deflected tip.
Fig. 28A and 28B show in perspective the placement of a helical anchor embodiment in a mitral valve position of the heart, the mitral valve of the heart being shown in partial cross-sectional view, the helical anchor being placed in the mitral valve position of the heart by means of a guidewire extending from the left atrium to the left ventricle under the native mitral valve leaflets.
Fig. 29A-29C show in perspective the placement of a helical anchor embodiment in a cardiac mitral valve location, shown in partial cross-section, with the helical anchor placed in the cardiac mitral valve location by means of a grasping tool to pull the helical anchor under the leaflets of the native mitral valve.
FIG. 30A is a close-up view of the grasping tool of FIGS. 29A-29C, showing the jaws closed to hold the end of the helical anchor.
FIG. 30B is a close-up view of the grasping tool of FIGS. 29A-29C, showing the jaws open to release the end of the helical anchor.
Fig. 31A-31D show in perspective the placement of a helical anchor embodiment in a cardiac mitral valve location, shown in partial cross-section, with the helical anchor placed in the cardiac mitral valve location by means of a clamping tool to center the system relative to the native mitral valve and to pull the helical anchor under the leaflets of the native mitral valve.
Figure 32A is a perspective view of one embodiment of a coiled delivery catheter or coiled guide catheter having a tip shaped such that when the shaft of the catheter is placed within a first commissure of a mitral valve of a heart, shown in partial cross-section, an end of the tip is positioned at a location substantially proximal to a second commissure of the mitral valve.
Figure 32B is a top view of the coiled delivery catheter or coiled guide catheter shown in figure 32A, showing the U-shaped portion of the coiled delivery catheter or coiled guide catheter traveling along the mitral annulus.
FIG. 32C shows in perspective the insertion of the grasping tool into the atrium for attachment to the helical anchor near its tip as the anchor is extruded from the coiled delivery catheter or coiled guide catheter shown in FIG. 32.
Fig. 32D is a close-up view of the grasping tool of fig. 32C as it is attached to the helical anchor near its tip.
Figure 32E shows the system of figure 32E in perspective with a grasping tool attached to the helical anchor and used to guide the helical anchor as the anchor is extruded from the coiled delivery catheter or the coiled guide catheter.
FIG. 33 is a perspective view of an alternative embodiment of a coiled delivery catheter or coiled guide catheter having a sail-like extension located on the wall of the left atrium shown in cross-section.
Figure 33A shows in cross-section the coiled delivery catheter or coiled guide catheter and sail-like extension shown in figure 33.
FIG. 34A shows in perspective one system according to the invention in which the snare catheter is attached near the end of a helical anchor extending from a coiled delivery catheter or coiled guide catheter into the atrium of the heart, which is shown in partial cross-section.
Figure 34B is a top view of the system shown in figure 34A showing the mitral annulus being substantially larger than the U-shaped portion of the coiled delivery catheter or coiled guide catheter.
Fig. 34C is a perspective view of the system of fig. 34A showing an anchor placed between the mitral valve leaflets at the junction via a snare catheter.
Fig. 34D is a top view of the system shown in fig. 34A, showing placement of an anchor through both the anterior and posterior mitral leaflets via the snare catheter.
Fig. 34E illustrates the system shown in fig. 34A-34D in perspective, showing placement of a tissue anchor through tissue, such as a mitral valve leaflet at a second junction, via a tissue anchor delivery catheter after the first junction has been plicating.
Figure 34F is a top view of the system shown in figures 34A-34E showing a complete plication at two junctions.
Figure 34G is a cross-sectional view of the pleat shown in figure 34F.
Fig. 34H is a cross-sectional view of a prosthetic mitral valve having a surface with helical grooves designed to engage a coil of a helical anchor that has been placed in the mitral position of the heart.
Fig. 34I is a cross-sectional view of a prosthetic mitral valve slot engaged with a coil of a helical anchor.
Fig. 34J is a cross-sectional view of an alternative helical anchor placed in the mitral position of the heart such that an anchor coil placed under the mitral valve leaflets is pressed against the leaflets or biased upward against the leaflets.
Fig. 34K is a top view of the helical anchor of fig. 34J showing the compression of the anchor coil placed over the mitral valve leaflets against the atrial wall when the anchor coil placed under the mitral valve leaflets is pressed up against the leaflets to close the commissures.
FIG. 34L is a cross-section taken along line 34L-34L of FIG. 34K.
Detailed Description
Referring initially to fig. 1A-1F, devices, systems, and methods for positioning a helical anchor within a mitral valve location of a patient's heart are illustrated. In this series of figures, the system is delivered from the apex of the left ventricle. However, it should be appreciated that the system may be used by implantation directly into the open heart from the atrium, ventricle or aorta, or the implantation may be delivered from a catheter into the left atrium or retrograde from the aortic valve into the left ventricle. Similarly, the system may be introduced into the atrium in the open chest or percutaneously via the apex of the heart.
Fig. 1A shows an introducer 2 inserted into the apex 6 of the left ventricle 10 of a patient's heart 14 through a small thoracotomy, sternotomy, or from below the diaphragm through an upper abdominal incision. A particularly advantageous approach is to make a small incision in the patient's chest adjacent the apex 6 of the left ventricle 10 and then through the apex 6 of the heart 14. To prevent blood leakage from the apex 6, standard purse string sutures can be used to hold the introducer 2 in place and close the defect when removed. Plugging devices may also be used for entry and exit. The aorta 18, aortic valve 22 and right ventricle 26 are shown for exemplary purposes. The guidewire 30 is advanced from the lumen 34 of the introducer 2 through the left ventricle 10 and passes between the anterior leaflet 38 and the posterior leaflet 42 of the native mitral valve 44 such that a portion of the guidewire 30 is positioned within the left atrium 46. When advancing the guidewire 30, care should be taken to avoid tangling of the guidewire 30 with the chordae tendineae 48 or their associated papillary muscles 56, 60. A delivery catheter 64 (fig. 1B) may then be advanced over the guidewire 30. The lumen 34 of the introducer 2 should be large enough to allow access to the various delivery system components.
In another embodiment, introducer 2 may incorporate a check valve (not shown) to prevent blood leakage. A number of such devices have been described which typically use one or more duckbill valves. The guidewire 30 may be straight or characterized by a U-shaped tip or any convenient shape to allow access into the left atrium 46.
As shown in fig. 1B, a delivery catheter 64 is introduced into the left atrium 46 over the guidewire 30. The delivery catheter 64 allows for the introduction of a coiled guide catheter 68. The coil guide catheter 68 has a pre-formed shape designed to facilitate introduction of the helical anchor 72, and may be constructed of any material and/or designed in any manner that allows it to be activated to the pre-formed shape during use. For example, it may be designed to be straightened and to retain its preformed shape when released. For example, the coil guide catheter 68 may be formed of a shape memory material such as nitinol (nickel titanium) or a plastic that retains its shape. Further, the coil guide conduit 68 may be a composite of several layers. For example, it may comprise a nitinol tube with a polymer coating. Furthermore, it may be composed of a mesh or fabric of nitinol with or without a coating. The interior may also be lined with a friction reducing material, such as a lubricious coating material, to make it smoother and smoother for introduction of the helical anchor 72. The coiled guide catheter 68 is straightened for introduction by the delivery catheter 64, and the delivery catheter 64 is relatively stiff compared to the coiled guide catheter 68. Other options for obtaining the pre-shaped shape may include introducing the distal end of the coiled guide catheter 68 as a straightening element, then activating it to assume the desired pre-shaped shape (such as having one or more curved portions as will be discussed below), and helping to properly introduce and position the helical anchor 72. One such activatable design would include small coiled sections with ramps that assume the desired shape when pulled together. Those skilled in the art will appreciate that the coiled guide catheter 68 may be guided to the mitral valve location without the use of a delivery device such as the delivery catheter 64. Any of a variety of known ways of deflecting the distal portion may be used for the purpose of manipulating the coiled guide catheter 68 or other catheter device used in embodiments of the present invention.
In one embodiment, the coil guide catheter 68 is positioned within the left atrium 46, or just inside the left ventricle 10 near the mitral valve junction 80. It should be noted that the commissure 80 is the point where the anterior mitral leaflet 38 and the posterior mitral leaflet 42 contact each other to close the mitral valve 44 at the valve periphery or annulus 84. If the heart 14 is open, the position can be visually confirmed. However, it is preferred to perform the procedure with the heart 14 closed and beating. In this case, imaging modalities such as fluoroscopy, X-ray, CT or MR imaging may be used. Two-dimensional or three-dimensional echocardiograms may also be used to help guide positioning. It should be appreciated that the coil guide catheter 68 may also be positioned within the left ventricle 10 for placement of the helical anchor 72.
When the delivery catheter 64 is removed, the coiled guide catheter 68 assumes its pre-shaped shape to facilitate introduction of the helical anchor 72, as shown in fig. 1C. The coil guide tube 68 includes a stem 88 and a U-shaped portion 92. The coil guide catheter 68 has an inner lumen 96 that is approximately circular with a diameter similar to the helical anchor 72 it delivers. The U-shaped portion 92 of the coil guide catheter 68 is oriented generally parallel to the plane of the mitral valve 44 and helps to properly position the depth of the coil guide catheter 68 within the heart 14 so that the helical anchor 72 is extruded into the plane of the mitral valve 44. This ensures that the helical anchor 72 will be guided tightly under the leaflets 38, 42. The tip 100 of the helical anchor 72 may also have a slight outward and downward curvature to allow the orientation of the helical anchor 72 below the valve leaflets 38, 42. The coil guide catheter 68 is shown with a slight upward bend at the rod 88 before the U-shaped portion 92, which is positioned parallel to the valve 46. This is not necessary, but helps to push the helical anchor 72 into place with less difficulty. It will also be appreciated that the distal portion of the coil guide catheter 68 need not be parallel to the valve 44 and annulus 84, as shown. Alternatively, it could be angled, and also the distal end of the helical anchor 72 would naturally orient itself downwardly and between the leaflets 38, 42, then be extruded and coiled or spiraled into place. It should also be noted that in each of the embodiments herein, valve, leaflet, or heart tissue puncture need not occur.
As shown in fig. 1C, the helical anchor 72 has been advanced such that the end of the helical anchor 72 begins to travel therealong below the trailing lobe 42. The end 100 of the coil guide catheter 68 is above the plane of the valve 46, but it could also be below the posterior leaflet 42. It should be noted that there is no need to pierce through tissue in any region. The helical anchor 72 passes between the leaflets 38, 42 near the commissures 80. It should be appreciated that piercing through the leaflets 38, 42 may be used, but is less desirable due to the vulnerability of the leaflets 38, 42. It is also possible to pass the helical anchor 72 at any location, including locations remote from the junction 80. Once the helical anchor 72 has been placed, this may cause one or both of the leaflets 38, 42 to fold or bend if the starting point is not at or near the commissures 80.
The helical anchor 72 is further advanced by being pushed through the coiled guide catheter 68. Fig. 1D shows a majority of a full turn helical anchor 72 positioned under the mitral valve 44. The number of lower coils 104 of the helical anchor 72 can vary from less than 1 to as many as deemed useful by the operator. After the lower coil of the anchor 72 is placed below the mitral valve annulus 84, the upper coil 108 of the helical anchor 72 is positioned above the annulus 84 by rotating the coil guide catheter 68 as the helical anchor 72 is advanced. This is shown in fig. 1E.
It is also possible to avoid rotation of the helical anchor 72 during delivery thereof over the mitral annulus 84, as the shape memory material will assume the correct position. However, it should be appreciated that if there is no rotation, the helical anchor 72 will spring and apply a force to the coil guide catheter 68. Another valuable option to insert the helical anchor 72 without requiring rotation of the coil guide catheter 68 is to straighten the coil guide catheter 68. When the coil guide catheter 68 has been straightened, the helical anchor 72 having the annular pre-shaped will not need to counter the pre-shaped shape of the coil guide catheter 68 and can resume its pre-shaped shape within the atrium 46.
After the helical anchor 72 is implanted, the coiled guide catheter 68 is removed. Fig. 1F shows about two coils 108 placed above the mitral valve annulus 84 and about two coils 104 placed below the mitral valve annulus 84. In other embodiments, the arrangement shown may vary. The coils 104, 108 may be any number as deemed appropriate by the operator. It should be noted that even a portion of the coils 104, 108 above or below the loop 84 may be sufficient to retain the helical anchor 72. It should be noted that the size of the helical anchor 72 may be preselected prior to placement so that it closely matches the diameter of the loop 84. This will maximize the size of the replacement valve implant that can be placed inside the helical anchor 72 and help reduce the risk of leakage at the commissures 80.
The gap between the coils 104, 108 can be adjusted when preparing the helical anchor 72. By leaving a slightly larger gap between the coils 104, 108 above and below the annulus, it is possible to allow the valve tissue 44 to close at the commissures 80 by allowing a small amount of movement of the leaflets 38, 42 as the heart 14 contracts. This is one strategy to ensure that there is no leakage around the helical anchor 72. The coils 104, 108 need not capture leaflet tissue 38, 42. Indeed, leaving a gap between the ventricular and atrial coils 104, 108 may be advantageous to allow the leaflet tissue 38, 42 to close at the ring 80 and prevent blood flow from leaking at these locations. In addition to leaving sufficient clearance between at least coils 104, 108 (i.e., clearance across loop 84 when anchor 72 is implanted), other ways of preventing capture of loop tissue are possible. For example, one or more atrial coils 108 may have a larger diameter or even be shaped differently than one "coil" such that it includes an extension that engages a portion of atrial wall 46 above ring 84. Various other designs for stabilizing the atrial and/or ventricular anchors are possible.
Fig. 1F shows the coil 104 wrapped around the anterior leaflet 38 of the mitral valve 46 near the aortic valve 22. The anterior leaflet 38 is engaged by the lower coil 104 of the helical anchor 72 and thereby restricts the flow of blood from being impeded into the aortic valve 22. The coil 104 may also be adjusted to be located even below the position shown if additional control of the anterior mitral leaflet 38 is desired. In other embodiments, the number of lower coils 104 in the helical anchor 72 may be adjusted to cover more of the anterior mitral leaflet 38. The lower coil 104 may be located high up against the ring 84 or lower within the ventricle 10.
It should be noted that once the helical anchor description 72 has been inserted as described herein, the patient's native mitral valve 44 continues to function, i.e., the leaflets 38, 42 continue to open and close as needed during the cardiac cycle. Although the coil 104 restricts some opening, the valve 44 can open and close normally so that the patient remains functionally stable. This allows the operator to implant the valve prosthesis into the anchor 72 without the patient being at risk of compromising the hemodynamic state. Thus, the procedure can be performed on a beating heart 14 without the need for a heart-lung machine. Another feature of this design is that when the replacement valve (i.e., prosthesis) is positioned, the position of the replacement valve (e.g., within the annulus, relatively higher than the annulus, or within the ventricle) can be selected by coiling the position of 104, 108 and making a decision by the physician as to the optimal position of the valve prosthesis. This allows the valve prosthesis or replacement valve implant to be positioned lower or higher within the ring 84 depending on the specific design of the helical anchor 72 and the anatomy and clinical condition of the patient.
Fig. 1G shows the helical anchor 72 implanted with about three coils 108 above the mitral annulus 84 in the left atrium 46 and about two coils 104 below the annulus 84 in the left ventricle 10. The anterior and posterior leaflets 38, 42 are engaged by the coil 104 of the helical anchor 72. Specifically, the anterior leaflet 38 is constrained by the coils 104, 108 such that it prevents obstruction of blood flow into the aortic valve 22. In this embodiment, the at least one or more coils 104 below the ring have a diameter that is greater than the diameter of the at least one or more coils 108 above the ring 84. This type of design may have many benefits. For example, it may help to close the junction 80, thereby preventing blood leakage at these locations after the procedure is completed. It may also assist in inserting the helical anchor 72 to initially begin extruding a larger diameter coil and then travel with a smaller diameter coil. Referring to fig. 1H, the use of a smaller diameter coil 108 at the location where mitral valve prosthesis 120 is to be implanted allows for the implantation of smaller sized prostheses 120, and this may be advantageous for various reasons. Some patients may have a larger diameter ring 84 and the physician may wish to implant a smaller prosthesis 120. This also helps prevent occlusion of the aortic valve 22. The valve prosthesis retention coil 108 (e.g., a smaller coil) may also extend higher into the left atrium 46 so that the prosthesis is also positioned higher and away from the aortic valve 22. It should be appreciated that the coils 104, 108 of the helical anchor need not have the same diameter. Rather, the diameter may vary for each bend or coil 104, 108 as is appropriate. Similarly, the coils 104, 108 need not be precisely annular. This may be beneficial in some embodiments where the coil has a curvature that is more oval or elliptical in shape. For example, an elliptical shape may be useful if the coil 108 above the ring 84 is positioned against the atrial wall 46a rather than on the native mitral valve 44 itself.
Still referring to fig. 1H, valve prosthesis 120 is held in the mitral valve position by helical anchor 72. Valve prosthesis 120 includes a pair of prosthetic leaflets 122, 124 mounted within an expanded stent structure 126. The prosthetic leaflets 122, 124 can comprise soft animal tissue, such as bovine, porcine, or equine pericardium or animal valve tissue. Variations of percutaneous valve 120 for implantation via a catheter have been described, such as those used in aortic valve replacement. Valve prosthesis 120 may be self-expanding, such as the previously described percutaneous valves based on shape memory stents such as nitinol (nickel titanium), or expandable balloons such as stainless steel or non-shape memory stent materials. The valve prosthesis 120 can be introduced into the apex 6 of the left ventricle 10 through the same introducer 2 shown at the beginning. This part of the procedure is well known because thousands of percutaneous valve implants are performed each year, and all suitable techniques and methods can be employed to insert the valve prosthesis 120 and anchor it into the helical anchor 72 as shown. The helical anchor 72 can be seen on X-ray, MR, CT, and echocardiography to assist in positioning the valve prosthesis 120 and performing the procedure. Radiopaque markers such as gold may be added to the surface of the shape memory material in order to improve X-ray recognition.
In this embodiment, valve prosthesis 120 is parked to helical anchor 72 such that the anterior and posterior leaflet tissue 38, 42 is secured between anchor 72 and valve prosthesis 120. This serves to lock the anchor 72 in place and prevent its movement or displacement. The leaflet tissue 38, 42 also forms a natural seal to prevent blood from flowing between the valve prosthesis 120 and the helical anchor 72. In other embodiments, locking of anchor 72 may also be accomplished by placing coil 108 of anchor 72 over mitral valve 44, such that upper coil 108 does not compress leaflets 38, 42 but rather abuts atrial wall 46 a.
Replacement valve 120 may be anchored against coils 108 of anchors 72 above ring 84, below ring 84, or both. Fig. 1H shows a valve 120, the valve 120 being relatively medial and anchored approximately equally against the coils 104, 108 in amounts above and below the ring 84. The exact location may be selected by the operator. Thus, coils 104, 108 may be adjusted (multiple coils 104, 108 on the atrial or ventricular side) to help facilitate positioning of valve 120.
To prevent helical anchor 72 from moving or sliding, it is helpful to compress leaflets 38, 42 between valve prosthesis 120 and at least a portion of helical anchor 72 below ring 84. Inserting valve prosthesis 120 into helical anchor 72 locks anchor 72 in place. An advantage of the coils 104, 108 pressing the valve prosthesis 120 against both above and below the valve 44 is that the movement of the coils 104, 108 will stop. The prosthesis 120 locks any coils 104, 108 it abuts against into a fixed and immovable position. This can be important because there is movement within the heart 14 with each heart beat. Nitinol and other shape memory materials are strong, but are known to have limited resistance to cyclic loading, causing them to fatigue and break rapidly. Therefore, it is important to prevent the movement.
It should be appreciated that in other embodiments, the valve prosthesis 120 may not be attached to the helical anchor 72 both above and below the ring 84. The coil 108 above the ring 84 need not necessarily abut against the valve prosthesis 120. Furthermore, anchoring of the valve prosthesis 120 can be achieved by simply engaging the anterior and posterior leaflets 38, 42 against the coils 104 below the ring 84. There may be minimal or no coiling 108 of the helical anchor 72 above the loop.
As previously described, the entire procedure may be performed through the atrium 46 or via transseptal puncture. More details of the transseptal procedure will be shown and described below.
It is not necessary that the coils 104, 108 of the helical anchor 72 engage both sides of the leaflets 38, 42. Fig. 1I shows an embodiment of a helical anchor 72 according to the present invention. The anterior and posterior leaflets 38, 42 are engaged by the coil 104 of the helical anchor 72 within the left ventricle 10 below the mitral annulus 84. Specifically, the anterior leaflet 38 is constrained by the coil 104, which prevents it from obstructing blood flow into the aortic valve 22. However, the coils 108 on opposite sides of the valve 44 within the left atrium 46 do not contact the leaflets 38, 42, but are anchored against the atrial wall 46 a. This arrangement prevents the anchor 72 from moving as described in the previous description, but relies on the atrial wall 46a to support the upper coil 108 instead of the leaflets 38, 42. The helical anchor 72 cannot move upward toward the atrium 46 due to contact with the leaflets 38, 42 below the valve 44, and cannot move downward due to contact with the atrial wall 46 a.
It should be appreciated that combinations of helical anchor variations can be used in other embodiments and are readily formed. For example, the helical anchor 72 may be configured such that the coils 104, 108 are located below the valve 44 and above the valve 44, but there is a gap between the coil 104 below the valve 44 and the coil 108 above the valve 44. The leaflets 38, 42 are not captured between the coils 104, 108 of the helical anchor 72. This arrangement allows the mitral valve 44 to naturally approximate at the commissure 80 and may prevent leakage at the commissure 80 since the leaflet tissue 38, 42 is not captured between the coils 104, 108. In another embodiment, additional coils 104, 108 may be added that will extend from the top of the aforementioned coil 108 within the left atrium 46 to anchor against the atrial wall 46 a. This arrangement may allow the valve prosthesis 120 to be secured to the coils 104, 108 above and below the ring 84 to improve the stability of the valve prosthesis 120 and to anchor to the atrial wall 46 a. It should be noted that both the diameter of the helical anchor 72 and the shape of the coils 104, 108 may vary, in addition to the gap between the coils 104 and 108. The helical anchors 72 need not be uniform in diameter or profile. For example, the coil 108 above the ring 84 may be made thicker than the coil 104 below the ring 84 in order to attach to the atrial wall 46a with greater strength. There may be thicker and thinner regions of the coils 104, 108 as required for strength or function. Furthermore, the cross-sectional shape of the coils 104, 108 need not be circular.
Fig. 1J shows valve prosthesis 120 anchored to helical anchor 72 shown in fig. 1I. In this embodiment, valve prosthesis 120 includes a pair of prosthetic leaflets 122, 124 mounted within an expandable stent structure 126. The prosthetic leaflets 122, 124 can comprise soft animal tissue, such as bovine, porcine, or equine pericardium or animal valve tissue. Various suitable valve prostheses have been described previously. In this embodiment, valve prosthesis 120 is parked to helical anchor 72 such that the anterior and posterior leaflet tissues 38, 42 are secured between anchor 72 and valve prosthesis 120. This serves to lock the anchor 72 in place and prevent it from moving or becoming dislodged (or loosened). The leaflet tissue 38, 42 also forms a natural seal to prevent blood from flowing between the valve prosthesis 120 and the helical anchor 72.
As described above, in other embodiments, the plurality of coils 108 can be placed over the ring 84 (in addition to the coils 108 contacting the atrial wall 46 a) such that the valve prosthesis 120 can be anchored to the coils 104, 108 of the helical anchor 72 above and below the ring 84, as previously described with reference to fig. 1H. The coil 108 above the ring 84 can easily not abut against the leaflets 38, 42, but rather there can be a gap between the coil 108 above the ring 84 and the coil 104 below the ring 84 so that the leaflet tissue 38, 42 is not captured between the coils 104, 108.
Fig. 1K shows a helical anchor 72 having a modified coil configuration. The anchor 72 is held in place by a coil 108a extending above the loop 84 against the atrial wall 46a and by a coil 104 extending below the loop 84 against the ventricular wall 10 a. The additional coil 108b above the ring 84 engages and holds the valve prosthesis 120 without contacting either of the anterior or posterior leaflets 38, 42. Valve prosthesis 120 includes a pair of prosthetic leaflets 122, 124 mounted within an expandable stent structure 126. The prosthetic leaflets 122, 124 can comprise soft animal tissue, such as bovine, porcine, or equine pericardium or animal valve tissue. Various suitable valve prostheses have been described previously. In this embodiment, the coils 104 of the helical anchor 72 below the ring 84 may not capture the anterior and posterior leaflet tissue 38, 42 between the anchor 72 and the valve prosthesis 120 sufficient to form a seal between the helical anchor 72 and the valve prosthesis 120 or to prevent the anterior leaflet 38 from obstructing blood flow into the aortic valve 22. Thus, in another embodiment, the coils 104 below the leaflets 38, 42 can be adjusted to hold the leaflets 38, 42 tightly against the valve prosthesis 120, rather than against the ventricular wall 10 a. Securing the anterior leaflet 38, such as in any manner described herein, may be important for the purpose of preventing obstruction of blood flow from the left ventricle 10 through the aortic valve 22. As previously described, coils 108a and 108b may be configured such that prosthesis 120 may be implanted at a desired height relative to ring 84. In addition to preventing occlusion of the aortic valve 22 by the prosthesis 120, this may prevent the prosthesis from contacting the wall of the left ventricle 10, which would result in rupture of the left ventricle 10. The latter case is particularly important for patients with small left ventricles.
The helical anchor of the present invention can be constructed in a number of variations. Fig. 2, 3 and 4 show an embodiment of a helical anchor 130 in which the lower coil 132 or first approximately two coils of the anchor 130 have a diameter that is larger than the diameter of the other upper coils 134. This allows for easy engagement with the mitral annulus 84 (fig. 1A) during insertion. In addition, lower coils 132 of anchors 130 extend slightly downward to form a gap, such that lower coils 132 do not press against each other, while upper coils 134 are shown in contact with each other. This feature allows the initial lower coil 132 to slide to the opposite side of the mitral leaflets 38, 42 as it is inserted and avoids unnecessary friction or drag as the anchor 130 is pushed into place. Both variants, whether included together or separately in other embodiments, can facilitate anchor placement and improve retention. Further embodiments not shown may include the following anchors: coils having different diameters; having coils spaced apart by different gap sizes; and coils that taper, expand or flare more or less. It should be noted that when valve prosthesis 120 (fig. 1H) is placed into or expanded within helical anchor 72 or 130, the coil may expand radially outward. This can be seen particularly in the middle coil. Thus, even though the coils may initially have different diameters, the coils each contact the valve prosthesis 120. It should also be noted that valve prosthesis 120 can have a varying diameter that can be designed to optimally contact a desired number of coils of helical anchor 72 or 130 for improved retention.
Fig. 5 shows an embodiment of the invention in which a helical anchor 140 for parking a valve prosthesis (not shown) is passed through one of the two commissures 80 of the mitral valve 44. The coils 142, 144 of the anchor 140 are positioned above and below the loop 84 and the connecting segment 146 is positioned across the junction 80 without passing through valve tissue.
Fig. 6 illustrates another exemplary embodiment of a helical anchor 150, wherein the anchor 150 is shaped as a simple helix, without a taper at one end, but with a slight outward bend 152 to facilitate initial rotation of the helical anchor 150 under the loop 84 (fig. 1A). In addition, gaps 154 are provided between coils 156 of anchor 150 to prevent unwanted friction or drag as anchor 150 is pushed into place. This slight outward bend or outward extension has a larger radius from the center of anchor 150 than the next adjacent coil. The distal end or outward bend 152 can also be oriented downward or away from the next adjacent coil in a direction generally along the central axis of the helical anchor 150 as shown. In this embodiment, distal portion 152 extends radially outward and downward relative to the next adjacent coil 154 to form a gap or space between end 152 and coil 154 that existed prior to implantation. This design feature also helps avoid entanglement with or interference with the chordae tendineae 48 and/or leaflets 38, 42 during insertion of the helical anchor 150, and requires a reduction in size when a smaller prosthesis 120 is to be implanted.
After the helical anchor is implanted and before the valve prosthesis is secured therein, the anchor may slip out of position or be completely displaced. Atrial anchoring features may be added to prevent this unwanted movement. For example, the helical anchor 160 may include a tail extension 162 as shown in fig. 7. The uppermost coil 162 may have a diameter greater than the lower coil 164 so as to contact or abut the atrial wall 46a, as shown in fig. 8. As previously described, the coil 164a of the helical anchor 160 below the mitral annulus 84 within the left ventricle 10 engages the anterior and posterior leaflets 38, 42. In particular, the anterior leaflet 38 is constrained by the coil 164a, which prevents it from obstructing the flow of blood into the aortic valve 22. The tail-like extension 162 helps prevent the helical anchor 160 from moving by applying a spring force against the atrial wall 46 a. It should be appreciated that in other embodiments, the tail extension 162 may not include a helical shape. For example, the tail extension 162 may comprise a simple straight segment that passes outwardly at an angle of about 90 degrees from the helical anchor 160. A wide variety of caudal extensions or other atrial anchoring features may be incorporated into the various embodiments. The tail-like extension 621 can completely eliminate the need for a coil 164b above the leaflets 38, 42 to coapt the leaflets 38, 42. The coil 164b over the leaflets 38, 42 can be eliminated or the coil 164b over the leaflets 38, 42 can be arranged to create a gap over the leaflets 38, 42. The gap may allow the helical anchor 160 to have much longer contact with the valve prosthesis 120 (fig. 1H). This may assist in orienting valve prosthesis 120 such that it is generally aligned into left ventricle 10 and atrium 46. It is important to ensure that the valve prosthesis 120 flowing into the ventricle does not abut against the posterior wall 10a of the left ventricle 10, as the abutment of the valve prosthesis 120 against the posterior wall 10a of the left ventricle 10 can cause wear and tear on the heart 14, or impede flow into the left ventricle 10.
If a gap between the upper and lower coils of the helical anchor is included in an embodiment of the invention, there can be weak points in the system that are prone to rupture, as previously described herein. The segment of the helical anchor connecting the coil above the valve 44 to the coil below the valve 44 can move and rupture regularly as the heart contracts. To prevent this unwanted movement, the valve prosthesis 120 is anchored to the coils both above and below the leaflets 38, 42, which locks the two helically coiled portions together against relative movement. Even if the joint between the upper and lower coiled portions were to break, the valve prosthesis 120 would hold the coils above the leaflets 38, 42 and below the leaflets 38, 42 together, similar to a splint. This will prevent partial embolization. It is also possible that the connecting section between the upper and lower helices will not be required after implantation of the replacement valve. The connection of the upper and lower coiled portions is only necessary for the insertion of the helical anchor. The connecting section between the upper and lower coiled portions can be made expandable (small and thin) or removable according to the purpose.
Referring now to fig. 9A-9C, embodiments of the invention are described in which a delivery device 180 includes an outer sheath 182 and an inner shaft 184 having a converging tip 186. A helical anchor 190 is placed on the shaft 184 and constrained within the sheath 182, shown in phantom, to tighten a coil 192 of the anchor 190 prior to implantation. The converging tip 186 is provided to assist an operator in guiding the device 180 through the patient's venous system (if used percutaneously) or through the patient's heart. An anchor arm 194, such as a hook, is disposed along the coil 192a of the helical anchor 190 and is constructed of a shape memory material. The anchor arm 194 has two spaced apart wire portions 194a, 194b to provide a forceful anchor point for holding tissue. The anchor arms 194 are constrained and straightened in a downward orientation within the outer sheath 182. When the delivery device 180 is removed, the coils 192 of the anchors 190 are released and elastically expand radially outward to their natural diameter, the anchor arms 194 fold in an upward direction forming hooks for engaging tissue, as shown in fig. 9B and 9C.
Referring now to fig. 10A-10C and 20-22, in one embodiment of the present invention, a delivery catheter 200 is inserted into the left ventricle 10 of a patient's heart 14. Delivery catheter 200 includes a lumen 202 carrying a delivery device 180 as previously described, for example, having an outer sheath 182 and a shaft 184 with a converging tip 186. A helical anchor 190 having anchor arms 194 is compressed over the shaft 184 and retained by the sheath 182, thereby tightening the coil 192 of the anchor 190. The tip 186 helps the delivery device 180 travel from the left ventricle 10 into the left atrium 46 between the anterior and posterior leaflets 38, 42 of the mitral valve 44, as shown in fig. 10A. When the outer sheath 182 is retracted, the helical anchor 190 elastically opens to its original size, as shown in fig. 10B and 20. The helical anchor 190, as with other embodiments, can take various forms, such as having coils 192 of varying diameters rather than coils of constant diameter, and/or engaging the atrial wall 46a in contact with or against leaflet tissue. For purposes of the surrounding environment, fig. 20 shows the right atrium 210, the inferior vena cava 212, the superior vena cava 214, the aortic valve 22, and the aorta 18 (shown in dotted lines). As outer sheath 182 slides downward relative to anchor 190, anchor arms 194 deploy and expand, e.g., into hooks. Hook 194 wraps around the anterior and posterior leaves 38, 42 and holds anchor 190 in place as shown in fig. 10B and 21. In this embodiment, the anchoring arms or hooks can capture or otherwise secure the leaflets 38, 42 and help prevent the anterior leaflet 38 from obstructing blood flow out of the left ventricle 10 through the aortic valve 22. It should be noted that the edges of the valve leaflets 38, 42 are attached to chordae tendineae 48 extending from the papillary muscles 56, 60. In this embodiment, the hook 194 is configured in a relatively narrow shape at the distal end 194C so as to pass between the chordae tendineae 48 (see fig. 9B and 9C). However, it should be appreciated that the hook portion 194 may be configured in a variety of shapes without departing from the scope of the present invention. For example, fig. 21 shows an alternative embodiment having a hook portion 194, the hook portion 194 being wide at the distal end portion 194c so as to form a loop. The wide loop hooks 194 of fig. 21 provide improved retention of the valve leaflets, but may be difficult to position around the chordae tendineae 48. Referring again to fig. 10A-10C, valve prosthesis 120 is positioned and held within helical anchor 190, as shown in fig. 10C and 22. In the embodiment of fig. 10C and 22, valve prosthesis 120 is mounted within a stent 126 and includes a pair of prosthetic leaflets 122, 124. The prosthetic leaflets 122, 124 can comprise soft animal tissue, such as bovine, porcine, or equine pericardium or animal valve tissue. Valve prosthesis 120 may be self-expanding or balloon expandable. The leaflet tissue 38, 42 is held by the hook 194 toward the valve prosthesis 120, preventing the anterior leaflet 38 from obstructing blood flow through the aortic valve 22. In the embodiment shown in fig. 22, a circumferential sleeve 220 is inserted between helical anchor 190 and valve prosthesis 120 to improve retention of valve prosthesis 120 in atrium 46 and to provide a seal between anchor 190 and valve prosthesis 120 to prevent leakage.
Fig. 11A-11C illustrate the transition of the anchor arm 194 from the straightened position (fig. 11A) to the activated position (fig. 11C). As previously described, the anchor arms 194 may be constructed of a shape memory material. Fig. 11A shows anchor arms 194 each having a fixed end 222 and a free end 224 disposed along coil 192 a. When the anchor arm 194 is released from the straightened position (fig. 10A), the free end 224 may move away from the fixed end 222, causing the base of the anchor arm 194 to elongate, and the distal tip 194c of the anchor arm 194 may begin to bend or fold upward, as shown in fig. 11B. When the distal tip 194C is bent to its original shape forming a hook as shown in fig. 11C, the anchor arm 194 is activated. In another embodiment, the anchor arm 194 may not have a fixed end 222, but rather two free ends 224, such that it can slide along the helical anchor 194 at both ends. The number and configuration of the anchor arms 194 provided may vary.
Fig. 12A shows a stent dock 230 according to another embodiment of the invention having anchor arms (such as hooks 232) at the bottom. The hook 232 may be attached separately to the configuration of the stent dock 230 or integrated into the configuration of the stent dock 230. The midpoint of the stand dock 230 is shown as a dashed line or axis 234. The hook portion 232 is attached to an apex 236 of each lowermost cell 238 of the stent dock 230. Other embodiments may include double-sided hooks (such as shown in fig. 11A-11C) that are anchored with one base portion on one unit 238 and one base portion on another unit 238. As the stent docks 230 expand, the cells 238 collapse vertically causing the hook portions 232 to rise, such as to engage the leaflet tissue. Shortening (i.e., radially expanding) the stent dock 230 in this manner can be used in a functional manner to activate the hook 232.
Fig. 12B shows another embodiment of the stent dock 240, which when expanded, the stent dock 240 shortens and the anchor arms, such as the double hook 242, are raised in a manner similar to that described with reference to fig. 12A. Other embodiments may include a variety of hook types and attachment structures. For example, a dual wire hook may be attached, with one wire end at the bottom of a first cell 244 of a stent dock 240 and the other wire end at the bottom of an adjacent cell 244 of a stent dock 240. This arrangement will cause the base of the hook portion 242 to elongate as the stand dock 240 expands. In this manner, the hook portions 242 may initially engage tissue having a narrow shape and then widen as the stent dock 240 expands. This can be a very useful feature when the hook 242 is attached to the valve leaflet between the chordae tendineae.
Referring now to fig. 13A and 13B, hook portion 250 is shown distributed along a serpentine wire 252. The bent portion 254 of the wire 252 separates the hook portion 250. When the wire 252 is straightened, the hook 250 is spread apart and becomes raised as shown in fig. 13B. In this manner, the hook 250 may be activated to hold tissue.
Similarly, fig. 14A and 14B show that the hook portions 250 are distributed along a serpentine wire 252, with the wire 252 mounted to a central retaining wire 256. As serpentine wire 252 is straightened along central retention wire 256, hook portions 250 spread apart and become raised as shown in fig. 14B. The central retaining wire 256 may comprise, for example, a helical anchor (such as described herein) on which the serpentine wire 252 is carried.
Fig. 14C and 14D illustrate yet another method of hook deployment according to an alternative aspect of the present invention. The wire 260 is folded such that a plurality of anchoring arms, such as hooks 262 having V-shaped portions, are provided. The wire 260 is placed into a housing or hollow structure 264 having an aperture 266, which allows the hook 262 to extend through the aperture 266 as shown in fig. 14C. When the pull wire 260 is passed through the housing 264, the V-shaped portion 270 retracts and is straightened within the housing 264 causing the hook 262 to lift upward as shown in FIG. 14D. There are many other ways of activating the hook portion that are associated with the elongation of the wire, stent parking portion, or helical anchor in accordance with the principles of the present invention.
Referring now to fig. 15A-15F, a system and method for positioning the stent dock 280 in the mitral valve position or position of the patient's heart 14 is shown. Fig. 15A shows the introducer 2 inserted into the apex 6 of the left ventricle 10 through a small thoracotomy, sternotomy, or from below the diaphragm through an upper abdominal incision. One particularly advantageous approach is to make a small incision in the patient's chest adjacent the apex 6 of the left ventricle 10 and then through the apex 6 of the heart 14. To prevent blood leakage from the apex 6, standard purse string sutures can be used to hold the introducer 2 in place and close the defect when removed. Occlusion devices that facilitate entry and exit may also be used. The guidewire 30 is advanced such that a portion of the guidewire 30 is positioned within the left atrium 46. When advancing the guidewire 30, care should be taken to avoid tangling of the guidewire 30 with the chordae tendineae 48 or their associated papillary muscles 56, 60. The delivery catheter 64 may be advanced over the guidewire 30.
The delivery catheter 64 includes a stent dock 280 and is guided into the left atrium 46. As shown in fig. 15B and 15C, while the stent dock 280 remains in place, the atrial portion 280a of the stent dock 280 is squeezed out (i.e., extended) by withdrawing the delivery catheter 64. This may also be accomplished by pushing the stent dock 280 outward from the delivery catheter 64. It should be appreciated that while the stent dock 280 may be constructed in a variety of ways, it is useful for the stent dock 280 to be constructed of a shape memory material such as nitinol. It should be noted that the stent dock 280 may be cut from a tube or sheet, or may be woven from a wire or sheet of shape memory material. Preferably, the cradle dock 280 has the option of allowing blood to flow around and through it. This is facilitated by the stent matrix as shown in fig. 15B. In one embodiment of the invention, portions of the stent dock 280 may be coated with one or more layers of fabric, polymer, and biomaterial. It should be noted that the fabric coating may be particularly beneficial in preventing leakage and promoting tissue ingrowth around the annulus 84 of the mitral valve 44. Suitable fabrics may include dacron and teflon materials.
After the atrial portion 280a of the stent dock 280 is released, as shown in fig. 15C and 15D, the stent dock 280 and the delivery catheter 64 are lowered together such that the atrial portion 280a of the stent dock 280 can contact the atrial wall 46a and the valve anchoring portion 280b of the stent dock 280 is positioned within the mitral valve 44, as shown in fig. 15D. The valve anchoring portion 280b may also be coated with a material such as dacron or polytetrafluoroethylene to promote tissue ingrowth and to help prevent leakage. As shown in fig. 15E, the delivery catheter 64 is further retracted and releases the anchoring arms of the stent dock 280 in the form of ventricular hooks 284 such that the hooks 284 ride between the chordae tendineae 48 and wrap around the mitral valve leaflets 38, 42. The stent dock 280 is held within the left atrium 46 by the atrial portion 280a and the stent dock 280 is held stable inside the heart 14. The valve anchoring portion 280b is in the closed position, but may expand apart in the direction of the arrow when inserting the valve prosthesis 120 (fig. 15G). It should be noted that the native mitral valve 44 can still be opened and closed so that the heart 14 remains functional and the patient remains stable during the procedure. Thus, there are no strict time constraints on the operator in preparation for implanting the valve prosthesis 120.
It should be appreciated that other methods of cradle dock deployment may be used within the scope of the present invention. For example, other embodiments (not shown) may include a delivery catheter device or a device configured such that the stent dock 280 may be released from both ends. In one embodiment, the catheter may hold the atrial portion 280a with or without the device's valve anchor portion 280b and a separate catheter may hold the ventricular hook 284. The closer catheter can be withdrawn to first cause hook 284 to open. This step may be performed with the hooks 284 lowered within the heart chamber 10 and the entire stent dock 280 may be pushed forward toward the valve 44, ensuring that the valve leaflets 38, 42 are retained by the hooks 284. If imaging (e.g., echocardiography) is used and shows portions of the valve leaflets 38, 42 are not hooked, the stent dock 280 can be pulled back and repositioned. When hooks 284 have properly engaged valve leaflets 38, 42, the more distal catheter may be withdrawn to expand atrial portion 280 a.
Other strategies may aid in the positioning of the cradle dock 280. For example, limiting the motion of the leaflets may help to allow hook portions 284 to secure all of the leaflet assemblies. This can be performed pharmacologically by reducing the flow through the mitral valve via drugs that negatively affect the force of muscle contraction or vasodilator drugs in order to worsen the blood circulation in the periphery of the patient or by table positioning. Mechanical devices such as occluders or balloons may be inflated near the mitral valve to restrict flow. Alternatively, the atrial portion 280a of the stent dock 280 may be adapted to reduce flow or may incorporate a flow reducing stent structure thereon. In another embodiment, atrial portion 280a may have a fabric partially attached to or covering its entire surface to restrict flow. The fabric may also be used to promote tissue ingrowth and long-term biocompatibility.
Referring now to fig. 15F, the stand dock 280 is positioned. The valve retaining portion 280b of the dock 280 expands or enlarges, causing the hook 284 to lift or move upward toward the atrial portion 280a of the dock 280. Hook 284 is pulled up over the mitral valve tissue so that valve 44 will no longer open and close. In addition, mitral leaflet tissue 38, 42 is compressed by hook 284 to form an excellent seal or seal around stent dock 280. The mitral leaflet tissue 38, 42 forms a ring of compressed native biomaterial that reinforces the dock 280 and prevents any leakage around the stent dock 280. Expansion of valve retention portion 280b thus causes atrial portion 280a and hook 284 to hold dock 280 in place. Expansion of the valve retaining portion 280b can be accomplished by various means. In one embodiment, a pull cord (not shown) may be used to pull hook 284 toward the atrial portion. Similarly, in another embodiment, a series of pull cords (not shown) may be used to pull hook 284 and the section of atrial portion 280a together.
It should be noted that the atrial portion 280a and the ventricular hook 284 of the device 280 can both have a variety of variations. For example, atrial portion 280a may not be comprised of a complete unit. In one embodiment, atrial portion 280a may include radial arms (not shown) that extend outward and are not a full turn of stent material. In another embodiment, atrial portion 280a may include a helical material similar to caudal extension 162 previously shown in FIG. 8 for anchoring a helical anchor within the atrium.
After successful placement of the stent dock 280, the individual valve prosthesis 120 is implanted within the valve retention portion 280b, as shown in fig. 15G. For example, valve prosthesis 120 may be as previously described. Expansion of valve prosthesis 120 may cause retention portions 280b to expand, allowing hook portions 284 and atrial portion 280a to securely retain stent dock 280. Alternatively, valve prosthesis 120 may be integrated within stent dock 280 prior to implantation in order to avoid a secondary step.
Fig. 16A-16C illustrate the stent dock deployed, with the delivery catheter not shown, to provide more detail. Atrial portion 280a is shown open in fig. 16A and 16B. The spaces between the struts 290 of the atrial portion allow for minimal or no interruption of blood flow. Fig. 16C shows the atrial portion 280a resting in the mitral valve plane 292 shown in phantom. Valve retention portion 280a begins to expand, causing hook 284 to rise. Fig. 16D shows valve holding portion 280b fully expanded, resulting in hooks 284 being lifted to their deployed position.
Referring now to fig. 17A-17D, a system and method for positioning the helical anchor 300 within the mitral valve position of a patient's heart 14 is shown. The catheter 302 is introduced into the patient's venous system by percutaneous puncture or a small surgical incision at the groin of the patient, as is well known. Alternatively, catheter 302 may be introduced anywhere in the lower abdomen or retroperitoneal region, or into the neck or shoulder region via the subclavian or axillary vein or jugular vein system of the neck. In this embodiment, catheter 302 is advanced up inferior vena cava 212, into right atrium 210, across interatrial septum 304, and into left atrium 46, as shown in fig. 17A. For purposes of illustration, the tricuspid valve 306, the right ventricle 210, the superior vena cava 214, and the aorta 18 of the patient's heart 14 are shown. A coil guide catheter 310 is carried by the catheter and extends between the anterior and posterior leaflets 38, 42 of the mitral valve 44 into the left ventricle.
In this embodiment, the system is preferably inserted through the venous system, which is low in pressure and can accommodate large catheters and introducers. This allows for some flexibility in improving and introducing catheters, systems, devices, and methods for remote mitral valve replacement. However, it should be appreciated that the system may be introduced directly into the left atrium 46 without the need for a transvenous approach or via the aorta 18. For example, the catheter 302 may be passed from the aorta 18 to the left ventricle 10 and then into the left atrium 46. The aorta 18 may be accessed directly, as in open-view surgery, or from any branch thereof, so that the system may be introduced into the groin, shoulder, retroperitoneum, chest, or abdomen of the patient.
In fig. 17B, the coiled guide catheter 310 extends into the left ventricle 10 and assumes its original shape. In this embodiment, the coil guide catheter 310 includes a shaft 312 and a U-shaped portion 314. The lower coil 316 (fig. 17C) of the helical anchor 320 is extruded (i.e., extended) from the coil guide catheter 310 into the ventricle 10. The lower coil 316 surrounds the chordae tendineae 48 and the mitral valve 44. The exact level (level) at which the lower coil 316 is pressed may be determined by adjusting the level of the coil guide catheter 310 within the left ventricle 10. In this embodiment, the compression starts below the level of the valve 44 so that the chordae 48 and the valve 44 are enclosed. It may be more convenient to enclose at a higher level. The chordae tendineae 48 originate from two papillary muscle heads 56, 60 located distally below the mitral valve 44. Since the chordae 48 are concentrated at a higher level near the papillary muscle heads 56, 60, it is desirable to surround the chordae 48 at a lower level.
When the lower coil 316 of the helical anchor 320 is delivered to under the mitral valve 44 as desired, the coil guide catheter 310 is pulled into the left atrium 46. See fig. 17C. The action of withdrawing the coil guide catheter 310 into the atrium 46 may be used to pull the lower coil 316 of the helical anchor 320 placed in the ventricle 10 to a higher level in order to contact the mitral valve 44, as shown in fig. 17C. The upper coil 322 of the helical anchor 320 is released into the atrium 46 by retracting the coil guide catheter 310 into the catheter 302. When the helical anchor 320 has been delivered to the position shown in fig. 17D, the coiled guide catheter 310 is retracted and the catheter 302 is withdrawn. In this embodiment, coils 316, 322 of anchor 320 contact mitral valve 44 both above and below leaflets 38, 42. However, it should be appreciated that other embodiments may have various arrangements, including those previously described. For example, the upper coil 322 may not contact the mitral valve 44, but may be supported against the atrial wall 46 a. In addition, a helical anchor 322 having a gap between the lower and upper coils 316, 322 may also be provided, such that the leaflets 38, 42 are not captured between the coils 316, 322 and may improve the orientation of a subsequently placed valve prosthesis (not shown). Fig. 17D also shows a ventricular coil 316 that houses the leaflets 38, 42. It will be appreciated that there may be gaps between the coils 316 and/or between the coils 322, and that a different number of coils than those shown in the drawings may be used. As a further example, if additional coils 316 are used within the ventricle 10, this may provide further prosthetic valve support and help further contain the leaflets 38 from obstructing the aortic valve 22. Additional coils 322 in the atrium 46 may also provide further prosthetic valve stability and also allow the prosthetic valve to be positioned higher up in the atrium 46 so that it does not obstruct the aortic valve 22.
It should be noted that when the helical anchor 320 is delivered in this manner, the lower and upper coils (i.e., ventricular and atrial coils) 316, 322 are joined by anchor segments located at the leaflets 38, 42. This can prevent the leaflets from closing and cause leakage in the valve 44. However, this condition does not last for a long time, as the percutaneous replacement valve 120 can be deployed immediately after placement of the anchors 320. In addition, the section of the anchor 320 that joins the atrial coil 322 and the ventricular coil 316 may be positioned proximate the junction 80 (fig. 15A) without interfering with valve closure. In another embodiment, the wire of anchor 320 may be pre-shaped so that it will travel through the center of the native mitral valve 44 and allow the two mitral valve leaflets 38, 42 to approach each other. A wide variety of helical anchor configurations such as those previously described herein may be incorporated.
Referring now to fig. 18A-18C, a system and method for positioning the helical anchor 330 within the mitral valve location of a patient's heart 14 is shown. As is well known, the catheter 332 is introduced into the patient's venous system by percutaneous puncture or a small surgical incision at the groin of the patient. Alternatively, catheter 332 may be introduced anywhere in the lower abdomen or retroperitoneal region, or into the neck or shoulder region via the subclavian or axillary vein or jugular vein system of the neck. In this embodiment, catheter 332 is advanced up the inferior vena cava 212, into the right atrium 210, across the interatrial septum, and into the left atrium 46, as shown in fig. 18A. The coil guide catheter 340 extends from the catheter 332 into the left atrium 46 with its distal tip 340a at or near the mitral valve 44. The helical anchor 330 is extruded from the tip 340a of the coil guide catheter 340 through the junction 80 between the anterior and posterior leaflets 38, 42, below the mitral valve 44. The coil guide catheter 340 includes a rod 342 and a U-shaped portion 344 to facilitate extrusion of the helical anchor 330.
In this embodiment, the system is preferably inserted through the venous system, which is low in pressure and can accommodate large catheters and introducers. This allows for some flexibility in improving and introducing catheters, systems, devices, and methods for remote mitral valve replacement. However, it should be appreciated that the system may be introduced directly into the left atrium 46 without the need for a transvenous approach or via the aorta 18. For example, the catheter 332 may be passed from the aorta 18 to the left ventricle 10 and then into the left atrium 46. The aorta 18 may be accessed directly, as in open-view surgery, or from any branch thereof, so that the system may be introduced into the groin, shoulder, retroperitoneum, chest, or abdomen of the patient.
After the lower coil 346 has been positioned in the ventricle 10 below the mitral valve 44 as desired, the upper coil 348 may be positioned in the atrium 46 above the mitral valve 44. In this embodiment, approximately two lower coils 346 of anchor 330 are located below mitral valve 44. It should be appreciated that any desired number of coils 346 may be provided below the mitral valve 44. By rotating the coil guide catheter 340, the upper coil 348 of the anchor 330 is released from the coil guide catheter 340 above the mitral valve 44, as shown in fig. 18B. In this embodiment, the catheter 332 has a bend 332 at its distal end. In other embodiments, bend 332a may be deactivated such that upper coil 348 is delivered over valve 44 from a position closer to septum 304. This will make it relatively easy for the coil 348 to assume its pre-formed position and will eliminate the need to rotate the conduit 332. Fig. 18C shows the helical anchor 330 fully deployed into the mitral position such that about two lower coils 346 of the anchor 330 are located below the mitral valve 44 and about two upper coils 348 are located above the mitral valve 44. In this embodiment, coils 346, 348 on either side of the valve 44 contact the leaflets 38, 42. After anchor placement is complete, the coiled guide catheter 340 is retracted and the catheter 342 can be withdrawn.
Referring now to fig. 19A-19E, a system and method for positioning a stent dock 350 in a mitral valve position of a patient's heart is shown. The stand dock 350 may be configured as described in connection with fig. 16A-16D, or in any other suitable manner, to carry out the principles of the invention as described herein. As is well known, the catheter 352 is introduced into the patient's venous system by percutaneous puncture or a small surgical incision at the groin of the patient. Alternatively, catheter 352 may be introduced anywhere in the lower abdomen or retroperitoneal region, or into the neck or shoulder region via the subclavian or axillary vein or jugular vein system of the neck. In this embodiment, catheter 352 is advanced up the inferior vena cava 212, into the right atrium 210, across the interatrial septum 304, and into the left atrium 46 towards the mitral valve 44, as shown in fig. 19A. A delivery catheter 354 extends from the catheter 352 across the mitral valve 44 into the left ventricle 10. The stent dock 350 is squeezed out of the delivery catheter 354 within the left ventricle 10 such that the hook portion 356 of the stent dock 350 is released from the delivery catheter 354 and positioned around the mitral valve leaflets 38, 42, as shown in fig. 19B. To ensure that all portions of the anterior and posterior leaflets 38, 42 are engaged by the hooks 356, the stent dock 350 may be pulled toward the valve 44, as shown in fig. 19C. If the method fails, the stand dock 350 is pushed forward and the process is repeated. Furthermore, if there is difficulty in engaging the two leaflets 38, 42, the hook 356 can be retracted into the delivery catheter 354 to restart or abort the procedure. After the hook 356 is successfully positioned, the entire stent dock 350 is released from the delivery catheter 354 such that the valve holding portion 350 is positioned between the anterior and posterior leaflets 38, 42 of the mitral valve 44 and the atrial portion 350a expands to its original shape within the left atrium 46, as shown in fig. 19D. The valve retaining portion 350b may have shape memory properties that allow it to self-expand, or the valve retaining portion 350b may be expanded by a balloon. Expansion of the valve retaining portion 350b causes the hooks 356 to move upward and secure the valve leaflets 38, 42 such that the hooks 356 and atrial portion 350a of the stent dock 350 clamp onto the mitral valve 44, stabilizing the stent dock 350 in place and forming a seal around the stent dock 350. In this embodiment, valve prosthesis 360 is integrated into the system, as shown in fig. 19E. Valve prosthesis 360 includes two prosthetic leaflets 362, 364 that are mounted within valve retaining portion 350 b. The prosthetic leaflets 362, 364 can comprise soft animal tissue, such as bovine, porcine, or equine pericardium or animal valve tissue, or any other suitable material as in all other embodiments. It should be appreciated that other embodiments may require the additional step of implanting a separate valve prosthesis within the valve retaining portion 350b of the stent dock 350.
In another embodiment, the orientation relative to the mitral valve 44 may be set. The anterior leaflet 38 is larger than the posterior leaflet 42 and is located adjacent the aortic valve 22, while the posterior leaflet 42 is closely associated with the posterior wall of the heart 14. It may be useful, for example, to provide a longer hook 356 on the stent dock 350 where the hook 356 attaches to the anterior mitral leaflet 38 at that stent dock 350. To orient the prosthesis 360, the operator may guide a guidewire or other orienting object (not shown) through the aortic valve 44. This will orient the operator on how to rotate the prosthesis 360 for optimal alignment. More specifically, the aortic valve 22 is located adjacent the anterior leaflet 38. Thus, inserting the guidewire through the aortic valve 22 will allow visualization, such as fluoroscopy, and display to the operator how to orient the stent dock 350 and properly orient or position the anchoring arm (e.g., hook 356) to hold and secure the anterior leaflet 38 so that it does not interfere with the aortic valve 22. Alternatively, the orientation may be performed automatically by guiding the guidewire through the aortic valve 44 such that the guidewire passes through a lumen on a delivery system (e.g., delivery catheter 352) adapted for the stent dock 350. A guidewire (not shown) may pass through the delivery catheter 352 and exit through the aortic valve 22 via the left ventricle 10. This would allow the operator to view the orientation of the delivery system by way of a fluorescent screen, for example. The stent dock 350 may then be guided through the delivery catheter 352 such that the channel within the delivery catheter holding the guidewire is adjacent to the portion of the stent dock 350 that will abut the anterior leaflet 38 and adjacent to those hooks or other anchoring arms that will secure the anterior leaflet 38. The position of the guidewire or other orienting structure causes the stent dock 350 to rotate so that it is oriented in this manner to the anterior mitral leaflet 38.
Referring now to fig. 23A-23D, a system and method for positioning a helical anchor 370 in a mitral valve position in a patient's heart 14 by way of an aortic guidewire 372 and a positioning screw 374 is shown. Guidewire 372 is advanced from lumen 376 of introducer 378 into left ventricle 10, through aortic valve 22, and into aorta 18. The right ventricle 210 is shown for illustrative purposes. The guidewire 372 may be used to position the anterior leaflet 38, which is adjacent the aortic valve 22. A coiled guide catheter 380 having a shaft 382 and a U-shaped portion 384 is advanced from the lumen 376 of the introducer 378 and positioned with its distal tip 380a within the left atrium 46, as shown in fig. 23B, such that the distal tip 380a of the coiled guide catheter 380 can be aligned away from the guidewire 372, as shown, or it can be aligned toward the guidewire 372. The operator may use fluoroscopy or echocardiography to determine the orientation of the distal tip 380a relative to the guidewire 372. If the distal tip 380a is aligned away from the guidewire 372, the operator will ensure that the subsequently positioned coil 374 will be squeezed from the coiled guide catheter 380 toward the posterior leaflet 42. Conversely, if the distal tip 380a is aligned toward the guidewire 372, the subsequently positioned coil 374 will be squeezed from the coiled guide catheter 380 toward the anterior leaflet 38. It should be appreciated that this type of guidewire assist may also be used via the atrial approach, where the guidewire 372 is delivered via a catheter from the atrium 46, then through the mitral valve 44 and rotated up through the aortic valve 22.
Prior to placement of the helical anchor 370 into the mitral valve location, a positioning helix or spring 374 may be advanced from the coiled guide catheter 380 into the left atrium 46, as shown in fig. 23B. The left atrium 46 is narrowed at the location of the mitral valve 44, such that the valve 44 resembles a drainage tube. The positioning screw 374 is shown larger than the diameter of the ring 84. For example, a positioning screw 374 having a maximum diameter of 40mm may be used for a 30mm ring 84. When the coil guide catheter 380 is positioned in the middle of the atrium 46, the positioning coil 374 is advanced so that the coil 374 will fully expand. When the coiled guide catheter 380 is retracted toward the mitral valve 44, the operator can feel the force of the helix 374 against the atrial wall 46a adjacent to the ring 84, and can also see the helix 374 deflected away from the plane of the valve 44 when fluoroscopy or echocardiography is used. Such a positioning screw or spring 374 is used to identify the location of the mitral valve 44 to more easily position the ring 84. The spiral element 374 may be made of any suitable metal, particularly a shape memory material. The illustrated screw element 374 has approximately one bend or coil, but may include any number of coils.
After the positioning screw 374 positions the mitral valve 44, the helical anchor 370 is advanced from the coiled guide catheter 380 into the atrium 46, through the commissures 80 of the mitral valve 44, and into the ventricle 10 below the valve 44, as shown in fig. 23C. The retaining spring 374 may then be removed from the atrium 46. In this embodiment, about two lower coils 390 of the helical anchor 370 may be positioned below the valve 44 by squeezing the helical anchor 370 from the coil guide catheter 380. Then, by rotating the helical guide catheter 380 as the helical anchor 380 is pushed forward, the upper coil 392 of the helical anchor 370 can be placed over the valve 44, as shown in fig. 23D. The positioning screw or spring 374 may be incorporated into any of the systems and methods described herein for positioning a helical anchor into a mitral valve location of a patient's heart.
Referring now to fig. 24A, 24B, and 24C, another embodiment of a system and method for positioning a helical anchor 400 within a mitral valve location of a patient's heart 14 by way of a positioning screw 402 is illustrated. As is well known, the catheter 404 is introduced into the patient's venous system by percutaneous puncture or a small surgical incision at the groin of the patient. Alternatively, catheter 404 may be introduced anywhere in the lower abdomen or retroperitoneal region, or into the neck or shoulder region via the subclavian or axillary vein or jugular vein system of the neck. In this embodiment, catheter 404 is advanced up inferior vena cava 212, into right atrium 210, across interatrial septum 304, and into left atrium 46, as shown in fig. 24A. A coiled guide catheter 406 extends from the catheter 404 toward the mitral valve 44 into the left atrium 46. The coil guide catheter 406 includes a shaft 408 and a U-shaped portion 410 for assisting in pressing the positioning helix 402 and the helical anchor 400 therefrom. The positioning helix 402 is squeezed from the coil guide catheter 406 and pushed against the bottom of the left atrium 46 adjacent the mitral valve 44. This may cause a return force that may be felt by the operator to confirm the location of the mitral valve 44. The helical anchor 400 is then squeezed from the coiled guide catheter 406 below the mitral valve leaflets 38, 42 using the positioning screw 402 as an introducer, as shown in fig. 24B. After a portion of the helical anchor 400 is placed under the leaflet 38, the positioning helix 402 can be removed. The catheter 404 is shown removed after completion of the placement of the helical anchor 400 (with coils 404, 406 above and below the valve, respectively) in fig. 24C. It should be noted that in other embodiments, the positioning helix 402 may have additional features. For example, it may include a caudal extension that may pass through the left ventricle and into the aorta (not shown) at its distal tip. This feature will ensure that the positioning helix 402 is substantially centered around the mitral annulus 84. In addition, the positioning screw 402 may deflect when pushed against the floor of the atrium 46. This deviation will be displayed to the operator on the screen and shows the position of the helix 402.
As previously described herein, when the end of the anchor delivery system is located inside the atrium 46, the helical anchor must be guided under the valve leaflets 38, 42. Thus, the attachment devices and methods now to be described are advantageous for assisting in positioning the start of the helical anchor below the valve leaflets 38, 42 without or with minimal visualization, and to maximize the position of the start of the anchor so that the coils of the anchor are ultimately positioned above and below the leaflets 38, 42.
Referring now to fig. 25A-25C, a system and method for positioning the helical anchor 420 within the mitral valve location of a patient's heart 14 is shown. A guidewire 422 is advanced from introducer 424 through left ventricle 10 and into left atrium 46 via mitral valve 44. A catheter 426 comprising a coiled guide catheter 428 with an attached pull cord 430 and a central lumen 432 is advanced over the guidewire 422 such that the coiled guide catheter 428 extends into the left atrium 46, as shown in fig. 25A. In another embodiment, the coil guide catheter 428 may have two lumens for the guidewire 422 and helical anchor 420, respectively. This variation prevents the two wires 420, 422 from interfering to facilitate passage through each other if the two wires 420, 422 are in place at the same time. Interference is particularly problematic in coiled guide catheters 428 having a single lumen when inserting the helical anchor 420 comprising a shape memory material, which can create kinks that can interfere with the movement of the guidewire 422 through the lumen 432. Neither lumen is necessary to access the end of the coil guide catheter 428. The pull cord 430 may be tethered around the coil guide catheter 428 or incorporated into the structure of the coil guide catheter 428, or it may pass through a loop (not shown) in the coil guide catheter 428 for securement.
As shown in fig. 25B, the coiled guide catheter 428 is initially straightened and activated to a complex curved shape to facilitate delivery of the helical anchor 420. In a typical case, the activated coiled guide catheter 428 features a two-way bend. In particular, the shaft 436 of the coil guide catheter 428 is curved such that its distal tip lies in a plane that is generally parallel to the mitral valve 44. The second bend 438 is generally parallel to the path of the mitral annulus 84. The helical anchor 420 is shown passing out of the coil guide catheter 428 and under the mitral valve leaflets 38, 42. Anchor delivery under the leaflets 38, 42 is facilitated by a pull cord 430. The pull cord 430 is pulled from the inside of the introducer 424 to draw the coil guide catheter 428 under the leaflets of the mitral valve 44. The coil guide catheter 428 may be temporarily pulled down into the left ventricle 10 until it is positioned under the leaflets 38, 42. The helical anchor 420 can be urged out of the coil guide catheter 428 and begin its bending or coiling below the leaflets 38, 42. It should be noted that the pull cord 430 passes between the leaflets 38, 42 to ensure that the coil guide catheter 428 will be drawn down between the leaflets 38, 42. The coil guide catheter 428 may be pulled downward (i.e., deeper into the left ventricle 10) in an exaggerated manner to ensure that the helical anchor 420 begins its curvature under the leaflets 38, 42. After the segments of the anchor 420 are delivered, the tension on the pull-cord 430 can be released so that the coil guide catheter 428 will return to its position just below the leaflets 38, 42 and the helical anchor 420 will be just below the leaflets 38, 42 by merely pushing it out of the coil guide catheter 428. In this embodiment, the procedure is performed via the apex 6 of the left ventricle 10. If the procedure is performed via transseptal puncture, the pulling motion will not work. A pushing motion would be necessary and therefore a somewhat rigid device would be required to move the end of the coil guide catheter 428 under the leaflets 38, 42. In one embodiment, this may be accomplished simply by advancing 430 through a tube or conduit and pushing onto the conduit (not shown). As shown in fig. 25B, pulling on the end of the pull cord 430 releases the kink 440 and allows the pull cord 430 to be removed. Other options exist including cutting the kink 440 or passing the draw cord 430 through a loop that allows it to be pulled freely.
Fig. 25C shows the placement of the helical anchor 420 over the valve 44 after the drawstring 430 is removed and the anchor is placed completely under the valve 44. The two coils or bends 442 of the helical anchor 420 are located below the mitral valve 44, while the additional bend 444 is placed above the valve 44 by rotating the coil guide catheter 428 while pushing out the helical anchor 420. It is not necessary to eject the helical anchor 420 and the rotating coil guide catheter 428 at the same time. These two steps may be performed separately. In another embodiment, the coil of the helical anchor 420 can be delivered into the atrium 46 before the tip 420a of the anchor 420 is pushed under the leaflets 38, 42 (fig. 25B). For example, two coils of the anchor 420 may be squeezed from the coil guide catheter 428 into the left atrium 46 before the tip 420a of the anchor 420 is guided under the mitral valve leaflets 38, 42. The tips 420a of the anchors 420 can then pass under the valve leaflets 38, 42 and have the other two bends advanced by simply pushing onto the helical anchor 420. This will result in the helical anchor 420 being positioned with two bends above the leaflets 38, 42 and two bends below the leaflets 38, 42. As previously described, different numbers of bends may be provided above and/or below the valve 44. By delivering the curvature of the anchor 420 prior to coaptation of the mitral valve leaflets 38, 42, the need to rotate the disc guide catheter 428 is eliminated. Only a pushing movement is necessary. This arrangement will allow the helical anchor 428 to be implanted by the operator simply pushing the catheter and tool into and out of the patient. In particular, any need to rotate and rotate the catheter remotely can make the procedure more difficult. Transmitting torque along the catheter is difficult, unpredictable, and may result in the catheter either not moving at all or bouncing unpredictably, which risks damaging the heart. It is easier and safer to perform a catheter procedure with only an in-and-out motion.
Referring now to fig. 26A-26C, a system and method for guiding a helical anchor 450 under the mitral valve leaflets 38, 42 is shown. A series of figures show the helical anchor 450 itself resiliently moving away from its neutral position and being pulled under the leaflets 38, 42. Snare 452 comprises a loop or wire of suture that can be pressed down into a catheter or tube 454. In one embodiment, material may be added to the ring 452 to allow it to be visible under fluoroscopy (i.e., radiopaque). Alternatively, snare 452 may be comprised of wire or wire inside a coating, such as a suture or polymer coating. The snare 452 is applied as shown by inserting the snare catheter 454 into the left atrium 46 and then widely opening the loop 452 to form a substantially larger target that allows the helical anchor 450 to pass. Fig. 26A shows snare 452 attached to the end of anchor 450 inside heart 14. However, this may be difficult to accomplish. Alternatively, the snare 452 may be inserted into the patient with the snare 452 pre-attached to the end of the helical anchor 450 (which may be slightly squeezed from the end of the coil guide catheter 456 and tied to the end of the coil guide catheter 456 before it is placed into the introducer 2). Alternatively, the loop 452 may be coupled to the end of the coil guide catheter prior to entry into the patient or while inside the heart. It will be appreciated that it will generally be easier to pre-loop the loop 452 to the end of the coil guide catheter 456 or to the tip or end of the helical anchor 450.
The snare catheter 454 and the coil guide catheter 456 pass through the same introducer 2 within the apex 6 of the left ventricle 10. When two subjects are passed through the same introducer, there is a tendency for blood to leak because the closure mechanism cannot seal around the space between the two subjects. It may be useful to change the design of the walls of the coiled guide catheter 456 and/or snare catheter 454 so that the two combine to form an easily closed perimeter. For example, the snare catheter 454 may be made flat or oval or crescent-shaped where it passes through the introducer 2 to reduce the risk of blood leakage by improving the seal. There may also be a slot on the introducer 2 for receiving the snare catheter 454.
In fig. 26B, the snare 452 is tightened around the end of the helical anchor 450, the end of the helical anchor 450 having been squeezed beyond the end of the coil guide catheter 456. The end of the helical anchor 450 has an enlarged tip 460 to prevent the snare 452 from sliding off the end of the anchor 450. The operator pulls the snare 452 to deliver the tip 460 of the helical anchor 450 under the mitral valve 44. As snare 452 passes between mitral valve leaflets 38, 42, helical anchor 450 will also pass between mitral valve leaflets 38, 42. To ensure that the anchor 450 is truly positioned under the valve leaflets 38, 42, the anchor 450 can be pulled into the ventricle 10 in an exaggerated manner before the coil 450 is advanced out of the coil guide catheter 456. Snare 452 may be released by pulling through a loop of suture or cutting the suture in or out of the patient.
In another embodiment, it may be advantageous to orient and deflect snare 452. Once the anchor 450 is pulled under the leaflets 38, 42, the tip 460 of the anchor 450 can advantageously be guided to the periphery of the valve 44, particularly to avoid entanglement with the chordae tendineae 48. This may be accomplished, for example, by passing a pre-shaped or malleable rod along the snare catheter 454 to impart a preferred shape thereto. The malleable rod allows the operator to change its curvature. The snare system may also have steerable features such as those described above with respect to the coiled guide catheter. A handle outside the patient's body may be used to adjust the bend on the snare system.
To ensure that the helical anchor 450 is wide enough to pass all of the chordae tendineae 48, it is advantageous to allow the snare 452 or suture to deflect toward the periphery of the valve 44 once the helical anchor 450 is pulled under the leaflets 38, 42. This may be accomplished by the stylet or snare tube 452 within the snare tube 454 having features such as those previously described with respect to the coiled guide catheter that cause it to change shape with a slight outward bend. The anchor 450 is then ejected until it is safely under the leaflets 38, 42, about 2 to 3 centimeters or about one quarter of a turn (so that the anchor 450 does not spring back into the left atrium 46). After pushing the anchor 450 a safe amount under the leaflets 38, 42, the snare 452 can be released. The anchor delivery is continued by pushing on the anchor 450 until the desired number of bends are located below the leaflets 38, 42. If a suture is used, it may be severed. A rigid rod may also be passed through the lumen independent of the suture 452 and still provide the same benefits.
Fig. 26C shows the tip 460 of the helical anchor 450 positioned below the valve 44 and released from the snare 452. A simple way to disengage anchor tips 460 from snare 452 is to pull snare 452 down until the anchor bends down into the left ventricle 10, and then release snare 452 so that anchor 450 is ejected from snare 452. The suture may also be cut outside the patient and then pulled through snare 452. The suture may also be passed through a preformed loop (not shown) in the tip 460 of the anchor 450. Alternatively, once the tip 460 of the anchor 450 is positioned below the leaflets 38, 42, the distal end of the coil guide catheter 456 can be advanced below the leaflets 38, 42 by rotating it. The snare 452 is then released slightly and the helical anchor 450 is then withdrawn into the coiled guide catheter 456, forcing the snare 452 out of the end of the anchor 450. The suture 452 and snare tube 454 may be withdrawn through the introducer 2 within the apex 6 of the left ventricle 10. Insertion of the anchor can be accomplished by pushing the remainder of the anchor 450 out under the leaflets 38, 42, as previously described herein.
Referring now to fig. 27A and 27B, the coil guide catheter 470 as previously described is shown with additional position setting features. Fig. 27A shows the coiled guide catheter 470 activated to a complex curved shape to facilitate delivery of the helical anchor 472. The activated coil guide catheter 470 features bends in both directions. Specifically, the shaft 474 of the coil guide catheter is bent so as to bring the distal end portion 476 of the coil guide catheter 470 into a plane generally parallel to the mitral valve 44. The second curved portion 478 is generally parallel to the path of the ring 84. In fig. 27B, the coil guide catheter 470 is shown with an additional bend 480 such that its tip 482 is deflected further downward. This downward deflection allows the tip 482 of the coil guide catheter 470 to pass easily under the mitral valve leaflets 38, 42. For example, the coil guide catheter 470 may assume the shape shown in fig. 27B while the helical anchor is delivered a few centimeters below the mitral valve leaflets 38, 42, and then may return to the shape shown in fig. 27A in order to ensure that the anchor 472 is properly positioned below the leaflets 38, 42.
Referring now to fig. 28A and 28B, systems and methods suitable for guiding the helical anchor 490 under the mitral valve leaflets 38, 42. This series of figures shows the delivery of a helical anchor 490 over a guidewire 492. The guidewire 492 is delivered through the end of the coiled guide catheter 494 such that the guidewire 492 passes under the mitral valve leaflets 38, 42 into the left ventricle 10 as shown in fig. 28A. A helical anchor 490 having a lumen 490a is then advanced over the guidewire 492 such that the anchor 490 passes under the mitral valve leaflets 38, 42 into the left ventricle 10, as shown in fig. 28B. The guidewire 492 may be withdrawn at any time after the anchor 490 has been successfully placed within the left ventricle 10. In this embodiment, the helical anchor 490 is configured as a solid tube or stent-like structure.
Referring now to fig. 29A-29C, a system and method for the helical anchor 500 to be guided under the mitral valve leaflets 38, 42 is shown. This series of figures shows the helical anchor 500 withdrawn from its neutral position by the grasping tool 502 and pulled under the leaflets 38, 42. The coil guide catheter 504 is shown positioned inside the left atrium 46 with the helical anchor 500 retained therein. The ends 506 (fig. 29C) of the helical anchor 500 are held by jaws 508, 510 of a separate grasping tool 502. Alternatively, the grasping tool 502 may be attached to the helical anchor 500 along the length of the anchor 500. The grasping tool 502 is functionally similar to the snare described previously herein, and may extend to the inside of the coil guide catheter 504, or it may hold the end 506 of the helical anchor 500 outside of the coil guide catheter 504, as shown in fig. 29A.
In this illustrative example, the grasping tool 502 features a U-shaped bend 512 to properly position the jaws 508, 510 of the tool 502 to grip the end 506 of the helical anchor 500. The need for the U-bend 512 may be eliminated simply by having a pivot joint, such as a universal joint connection between the end of the grasping tool 502 and the end 506 of the helical anchor 500. Alternatively, the balloon on the end 506 of the helical anchor 500 can mate with a groove in the jaws 508, 510 of the grasping tool 502, allowing it to be engaged at any angle. The grasping tool 502 can be used to drag the helical anchor 500 under the mitral valve leaflets 38, 42, as shown in fig. 29B. The grasping tool 502 need not be curved, but may be passed in a straight line into the left atrium 46. When the helical anchor 500 is positioned below the leaflets 38, 42, the grasping tool 502 is released and can be withdrawn from the heart 14, as shown in fig. 29C. The anchor 500 may then be advanced into position under the mitral valve leaflets 38, 42, as previously described herein. The grasping tool 502 may be similar in function to a bioptome.
Fig. 30A and 30B illustrate an alternative grasping tool 520 according to the present invention. Grasping tool 520 includes a pair of jaws 522, 524 and a conduit 526 that allows jaws 522, 524 to open and close. The catheter 526 can be advanced toward the jaws 522, 524 to close and hold the end 506 of the helical anchor 500, as shown in fig. 30A. When the catheter 526 is retracted, the jaws 522, 524 open and the helical anchor 500 is released, as shown in fig. 30B. The grasping tool 520 is more flexible and thinner than biopsy forceps. Further, the anchor 500 is rotatable within the jaws 522, 524 of the grasping tool 520. This combination acts as a universal joint, allowing the spherical end 506 of the helical anchor 500 to rotate inside the grasping tool 520. This allows the coil guide catheter 504 and the grasping tool 520 to be inserted in parallel paths without the need for the U-bend 512 shown in FIG. 29A. As previously described herein, it is not necessary for the grasping tool 520 to hold the end 506 of the helical anchor 500. Rather, the grasping tool 520 can latch onto the helical anchor 500 at any location along its length. When the grasping tool 520 is latched onto the side of the helical anchor 500, the helical anchor 500 can be allowed to slide through the jaws 522, 524 so that the anchor 500 can be pushed into place while the jaws 522, 524 are closed and the grasping tool 520 remains in place.
Referring now to fig. 31A-31D, a system and method for positioning a helical anchor 500 within the mitral valve location of the heart 14 is shown. Coil guide catheter 504 and separate grasping tool 520 are advanced through introducer 2 into left atrium 46. The end 506 (fig. 31C) of the helical anchor 500 includes a bulbous tip that extends from the coiled guide catheter 504 and is retained by jaws 522, 524 of a grasping tool 520. A portion of the helical anchor 500 is positioned within the atrium 46 by pushing the anchor 500 through the coiled guide catheter 504, as shown in fig. 31A. After approximately two coils 530, 532 have been positioned within the atrium 46, the grasping tool 520 is retracted through the junction 80 to drag the end 506 under the mitral annulus 84, as shown in fig. 31B. When the end 506 of the helical anchor 500 has been dragged under the loop 84, the grasper 520 releases the end 506 of the anchor 500 and is withdrawn from the heart 14, as shown in fig. 31C. The helical anchor 500 is then further extruded from the helical guide catheter 504 such that approximately two coils 534, 536 of the anchor 500 are positioned below the loop, as shown in fig. 31D. It should be noted that this embodiment does not require any twisting or bending of the coiled guide catheter 504, but rather delivery of the helical anchor 500 can be accomplished by mere squeezing.
It should be noted that when the grasping tool 520 is clamped onto the tip 506 of the helical anchor 500, the grasping tool 520 may wrap around the shaft of the coiled guide catheter 504 when the bend of the anchor 500 is compressed. This wrapping may be counteracted by having the grasping tool 520 pre-wrap the shaft of the coiled guide catheter 504 in the opposite direction before it is inserted into the heart. Alternatively, the grasper tool 520 may be clamped to the tip 506 of the helical anchor 500 after the bends or coils 530, 532 of the anchor 500 are extruded into the atrium 46. However, it is very difficult to do this with minimal or no visualization. In addition, magnetic material may be added to the ends of the grasping tool 520 and the helical anchor 500 so that they may be joined by approximating their distal ends. One or both distal ends of the grasper and anchor 500 may be magnetic. If only one is magnetic, the other end must contain a material such as iron that is inducible to have a magnetic field. Even with the aid of magnets, it can be very difficult to perform the process in a minimally or non-visualized manner. Thus, other means may be provided to prevent the gripping tool and the coil guide catheter from twisting together. It should also be understood that while the grasping tool and snare catheter are specifically disclosed herein as suitable control elements for the purpose of other components of the guide system, such as the coiled guide catheter and/or the helical anchor, other control elements may be used instead. As one other possible option, a simple cable, suture, or other tensile member may be used to pull the distal end of a catheter (such as the coiled guide catheter of the present invention), or otherwise directly or indirectly onto the helical anchor itself for positioning purposes.
Referring now to fig. 32A-32E, a system and method for guiding a helical anchor 500 under the mitral valve leaflets 38, 42 is shown. The coil guide catheter 504 is advanced through the introducer 2 into the left atrium 46 so that the shaft of the coil guide catheter 504 is placed into the junction 80 of the mitral valve 44. The end 504a of the coil guide catheter 504 is shaped so that it is positioned adjacent to the other junction 80. The length of the coil guide catheter 504 can be selected such that when the helical anchor 500 is compressed as shown in fig. 32A, the end 506 of the anchor 500 can be grasped by the grasping tool 504 precisely through the joint 80. The plurality of coiled guide catheters may be manufactured in various sizes to match mitral valves of different sizes. For example, when performing a procedure on a patient with a mitral valve diameter of about 30mm (typically shown on echocardiography and also CT and MR scans), the operator may select a coiled guide catheter 504 having a length of about 30mm between the end of the shaft and the tip 504a of the introducer 504.
Fig. 32B shows a view of the mitral valve 44 from above. The coil guide catheter 504 passes through the mitral valve 44 at the junction 80 shown on the right. The shaft 504b of the coil guide catheter 504 may be ultrasonically guided to one of the junctions 80. The end of the coil guide catheter 504 has a U-shaped portion 504c that resembles the arc of the posterior mitral annulus, with the distal tip 504a located near the other commissure 80 so that the helical anchor 500 can be squeezed therefrom and pulled under the leaflets 38, 42 by a grasping tool 540. It should be noted that it is not necessary to position the entry point of the anchor 500 at the junction 80. However, it is important to recognize that if the helical anchor 500 begins in the middle region of the anterior mitral leaflet 38, for example, that portion of the leaflet 38 will be captured within the coil and can cause problems, such as leakage of the valve 44 after insertion of the anchor 500. If the valve 44 leaks, the patient becomes hemodynamically unstable and the procedure may rush to insert the mitral valve prosthesis.
As shown in fig. 32B, the U-shaped portion 504c of the coil guide catheter 504 travels along the ring 84 of the valve 44. The U-shaped portion 504c may also travel along a portion outside of the loop 84 such that the coil guide catheter 504 is positioned against the left atrial wall 46a above the bottom of the heart 14. This provides the coil guide catheter 504 with a stent that may rest thereon. The operator may pull the rod 504b of the coil guide catheter 504 downward and feel the coil guide catheter 504 engages against the bottom of the heart 14. This would allow for relatively blind positioning of the depth of the coil guide catheter 504 within the heart 14.
The grasping tool 540 is advanced through the introducer 2 into the left atrium 46 such that the grasping tool 540 passes through the mitral annulus 84 near the junction 80, as shown in fig. 32C. The grasping tool 540 includes jaws 542, 544, the jaws 542, 544 initially opening to receive the helical anchor 500. The grasping tool 540 can then grasp the helical anchor 500 proximate the tip 506 of the helical anchor 500 such that the anchor 500 can slide through the jaws 542, 544 of the grasping tool 540, as shown in fig. 32D. In one embodiment, the grasping tool 540 may have locks on the jaws 542, 544 so that an operator does not have to hold 540 closed. Such locks are well known and have been described for many tools such as endoscopic biopsy forceps. It should be noted that the operator will preferably clamp the grasping tool 540 to the helical anchor 500 outside the patient's body prior to inserting the coil guide catheter 504 and the grasping tool 540 into the heart 14. Fig. 32E shows the helical anchor 500 sliding between the jaws 542, 544 such that the grasping tool 540 guides the anchor 500 to advance under the leaflets 38, 42. Jaws 542, 544 are located above valve 44, but it should be appreciated that jaws 542, 544 can alternatively be located below valve 44 or at the same level as valve 44 in order to align the path of anchor 500. The grasping tool 540 can be used not only to pull the anchor 500 under the loop 84, but can also control the movement of the anchor 500 and guide the anchor 500 into place. If the anchor 500 becomes sticky during rotation, the anchor 500 can be advanced or withdrawn by moving up and down on the grasper tool 540 to help release the anchor 500. In another embodiment, the grasping tool 540 may also be attached to the tip 506 of the helical anchor 500 such that it can rotate with the anchor 500. If the tip 506 of the helical anchor 500 cannot move forward, the grasper 540 can rotate along with the anchor 500 and by pushing and pulling the grasper 540, the tip 506 of the anchor 500 can be induced to make a complete rotation around the underside of the valve 44.
The distance of the coil guide catheter 504 from the shaft 504b to the tip 506 of the coil guide catheter 504 along the U-shaped portion 504c may be approximately the diameter of the mitral annulus or the distance between the junctions 80. When the distance from the end of the rod 504b to the end 506 of the coil guide catheter 504 is about the mitral valve diameter or the distance between the commissures, the grasping tool 540 and the rod 504b can be spaced apart by the distance of the mitral valve diameter or the distance between the commissures so that the system is centered within the mitral valve 44. The junction 80 is easily identified on the echocardiogram. By ensuring that the rod 504b and grasping tool 540 are located within the commissures 80, the delivery of the coil 500 can be properly oriented relative to the leaflets 38, 42. Most operators will likely want the delivery of the coil 500 to begin at the junction 80 so that the orientation of the coil guide catheter 504 and grasping tool 540 as shown will ensure the correct starting position for the helical anchor 500 entry point.
It should be reiterated that it is not necessary to deliver the helical anchor 500 at the junction 80. The coiled guide catheter 504 may be rotated to access any access point. However, the joint 80 may be an advantageous starting point, which may ensure the position of the shaft 504b and the grasping tool 540 of the coil guide catheter 504. The coil guide catheter 504 and the grasping tool 540 can then be rotated to any desired entry point suitable for the helical anchor 500.
Sometimes there is calcium under the mitral leaflets 38 and/or 42. When the helical anchor 500 encounters deposited calcium, the helical anchor 500 does not easily slip. The grasping tool 540 can be pulled down and the anchor 500 moved to a slightly lower position for passage around the calcium. Similarly, the helical anchor 500 may be off-course rather than rotated to a position directly below the valve 44 and in the plane of the valve 44, it may take a skewed course. The gripping tool 540 may be used to prevent or remedy the problem. By sliding the helical anchor 500 between the jaws 542, 544, the anchor 500 can be maintained in a desired rotational path. It should be noted that the gripping tool 540 is easy to remove. The jaws 542, 544 can be opened and the tool 540 simply pulled out of the introducer sheath 2.
Referring now to fig. 33 and 33A, features for positioning the coil guide catheter 560 within the left atrium 46 are shown. The coiled guide catheter 560 with the membrane extension 564 is advanced into the left atrium 44 through the junction 80 of the mitral valve 44. The extension 564 lies in the same plane as the U-shaped portion 570 of the coiled guide catheter 560 and travels beyond the periphery of the mitral annulus 84 so that it lies on the wall 46a of the left atrium 46. Alternatively, the extension 564 may have a downward bend that forms an arcuate channel around the U-shaped portion 570 of the coil guide conduit 560. This downward curvature may create a space for the coil to be positioned over the ring 84, and the operator may wish to compress the coil of the helical anchor 572 prior to placing the tip 574 of the anchor 572 under the mitral valve 44. Referring to fig. 33, the extension 564 locates against the atrial wall 46a and provides tactile feedback to the operator by creating a distinct stop point when the operator pulls the disk around the guide catheter 560 back. This serves to hold the coiled guide catheter 560 within the left atrium 46 and in a plane parallel to the plane of the valve 44. In this manner, the extensions 564 provide assistance in proper depth positioning of the helical guide catheter 560 and help keep the helical anchor 572 delivered substantially parallel to the plane of the valve 44. In this embodiment, the extension 564 extends along the length of the U-shaped portion 570 of the coil guide conduit 560. However, in other embodiments, the extension 564 may be shorter or longer, even such that the extension 564 may form a complete ring around the mitral annulus 84. Further, the extension 564 may include a plurality of smaller, individual protrusions or extensions that perform a similar function, rather than including a continuous protrusion as shown.
The extension 564 may comprise a film of plastic material or biomaterial. Any suitable biocompatible material may be used, such as nylon, polypropylene, polyester, polytetrafluoroethylene, or expanded polytetrafluoroethylene. Biological materials such as animal or human pericardium or gut membrane from animals may also be used. Filamentary structures 576 may impart shape and integrity to film 564. The wire can move to activate the sail-like membrane 564. For example, pushing on the wire may move the sail-like membrane 564 from a collapsed position, in which the membrane 564 is positioned proximate to the coil guide catheter 560, to an activated position, in which the membrane 564 expands and provides support of the coil guide catheter 560 on the atrial wall 46 a. The wire material may be made of any suitable material, such as stainless steel or nitinol.
Referring now to fig. 34A-34G, devices, systems, and methods of closing a commissure 80 of the mitral valve 44 are shown. In fig. 34A, the snare catheter 580 is attached to the end of a helical anchor 500, the helical anchor 500 extending from the end of the coiled guide catheter 504 within the left atrium 46, as has been described previously. The suture 582 is kinked 584 to attach the snare catheter 580 to the end of the helical anchor 500. In other embodiments, it is not necessary to use a kink for this connection. For example, the suture 582 may be threaded through loops at the anchor ends. Or the snare may be cinched around the end of the anchor. However, in this embodiment, the kink 584 facilitates maintaining attachment to the helical anchor 500 and controlling the helical anchor 500 to prevent disconnection when the snare catheter 580 is released. Suture 582 may be severed at the end of the procedure or at any time during the procedure. There are several devices described for severing sutures passing through a catheter. The snare catheter 580 passes between the leaflets 38, 42 of the mitral valve 44 near the commissures 80, and the coil guide catheter 504 passes between the leaflets 38, 42 of the mitral valve 44 near the opposite commissure 80, as shown in fig. 34B. The mitral annulus 84 shown here is large, such that a gap of about 4 mm to 5mm is shown between the leaflets 38, 42 at each commissure 80. This may cause severe leakage after installation of helical anchor 500 and valve prosthesis 120. To prevent this leakage, the operator may continue to implant the mitral valve prosthesis 120 as desired herein and then add progressively larger amounts of fabric covering (fig. 22) to occlude the gap between the valve prosthesis 120 and the mitral annulus 84. However, for catheter-based implants, it is difficult to add a sufficient amount of fabric sleeve because the material volume is large. An alternative solution is to provide a valve prosthesis that is large enough to accommodate a large mitral annulus 84. However, large valve prostheses can also be difficult to implant through a catheter. Both large sized valve prostheses and prostheses with a sheath material will require large delivery systems that require large incisions and surgical incisions to gain access to the heart or vascular system.
Alternatively, the mitral leaflets 38, 42 can be closed together, or the space between the leaflets 38, 42 can be plugged or plugged. Various means may be used to block leakage at the joint 80. Devices similar to occluders (Amplatzer) are constructed from coils of metal such as nitinol or stainless steel. They may have a fabric coating or a fabric inside to increase the procoagulability and reduce leakage. These occlusion devices may be used to close atrial septal defects, patent foramen ovale, valve leaks, and the like. These may also be used in this case. Other devices and methods may be used to close the joint 80. A fabric tampon may be used to close the gap. A fabric structure having an hourglass shape is one variation that would be insertable for this purpose, such that a narrow portion of the fabric is located within the commissures 80 and a larger portion of the fabric is located above and below the leaflets 38, 42. The plugging material will wrap around the helical anchor 500. It need not be located just outside of anchor 500. The anchor 500 can hold the plugging material so that there is no risk of material displacement. It is also possible to form a blocking device, system and method that can be integrated or straddle onto the coil of anchor 500. A tampon or occluder or other occluding device may be anchored to the coil and form a closure at the juncture. For example, two obturators may be pre-attached to the coil before the coil is inserted. An obturator may be delivered to the first junction 80. The coil 500 may be advanced to the opposite junction 80 and a second obturator may be delivered to that location. The plug may travel along a rail-like coil 500 and be pushed around the helical anchor, for example using a cannula fed over the anchor 500. It is also possible to insert the helical anchor 500 and thereafter deliver the plugging material along the trajectory or rail of the helical anchor 500. The imaging system may be used to confirm the absence of leakage (e.g., with an echocardiogram). Additional plugs may be added until no further leakage occurs. In another embodiment, an unsupported plug may be used to close or close the ring 80 and prevent leakage. It should be noted that the occluder can be delivered during or after positioning the helical anchor 500.
Another option to prevent leakage around the anchor is to close the anterior and posterior lobes 38, 42 together around the helical anchor 500. Fig. 34C shows the leaflet anchor 590 being placed through the mitral leaflet 42. When the helical anchor 500 is in the correct position, the snare catheter 580 is released and maneuvered to the outside of the helical anchor 500 to one of the leaflets 38, 42. Imaging using fluoroscopy and echocardiography or other techniques may assist in this step. A rigid rod or catheter control steering system may facilitate steering of the catheter. The snare catheter 580, or a catheter or lumen associated therewith, also delivers the leaflet anchor 590. The snare catheter 580 may be, for example, a simple double lumen catheter or a single catheter for delivery of the leaflet anchor 590 may be attached to the snare catheter 580 near their ends.
In one embodiment, the leaflet anchor 590 is T-shaped and inserted similar to the fabric tag anchors commonly used on garments, such that the long and short stems of the T-shape are parallel during insertion. The T-shaped anchor 590 has one sharpened end for piercing tissue. The sharp end is fed through the catheter 592 and pushed through the leaflet 42. In another embodiment, the leaflet anchor 590 may be delivered through a cylindrical tube having a sharpened end for piercing leaflet tissue. A catheter with a needle-like distal tip may be used to deliver anchor 590 through the lobular tissue. In any event, the catheter 592 is withdrawn after the T-anchor is ejected. This leaves the T-shaped anchor on the atrial side of the leaflet 42, with the tail 594 of the anchor traveling through the valve tissue into the catheter 592.
Once the leaflet anchor 590 has passed through the tissue, it returns to its original T-shape. The leaflet anchor 590 is then pulled flush with the valve tissue. As shown in fig. 34D, the same process is repeated for the other leaflet 38 and the other anchor 590. As shown in fig. 34G, the individual anchors 590 are then tightened by securing the suture ends or tails 594 of the individual anchors 590 together. Tissue suture catches 596 may be used to enhance attachment. The latches 596 may be formed from one or more of plastic and metal materials. After the plication is completed, the suture tail 594 is cut.
Fig. 34E shows the advancement of the second snare catheter 600 over the coiled guide catheter 504 toward the second junction 80 of the mitral valve using the suture connection 602. The T-shaped anchor plication process is repeated for the anterior and posterior leaflets 38, 42. Fig. 34F shows the completed pleats at these two junctions 80.
Alternatively, the helical anchor 500 may be used to enable a pleat to be formed at the second connection 80. The helical anchor 500 can be advanced to the second junction 80 by pushing it forward. The correct position for the tip of the helical anchor 500 and the anchor delivery system can be indicated by the position of the rod 504b and using imaging methods that can include fluoroscopy, echogenicity, MR, and CT. The helical anchor 500 carries and positions the delivery of any anchor or system to plicating the leaflets 38, 42 or annulus 84. Once the correct position is achieved at the junction 80 shown on the left, the fastener or anchor 590 is again placed through the anterior leaflet 38, posterior leaflet 42, or loop 84 as needed. The anchors 590 may then be locked together and the suture tails 594 cut to complete the procedure. It should be reiterated that these particular anchors 590 need not be used to perform joint plication. Any of a number of such systems may be used in conjunction with the orientation and delivery methods and devices described in this disclosure.
In another embodiment, a single anchor may be formed that delivers the anchor to each of the anterior and posterior leaflets 38, 42. The two anchors can be held together after delivery by a suture or elastic material and a spring-closing member so that the leaflets 38, 42 are approximated between the helical anchor and the annulus. This concept of incorporating an anchor is applicable not only to T-shaped anchors, but also to any anchor.
The helical anchor 500 and/or the coil guide catheter 504 serve as an introducer for delivering the leaflets and/or the annular anchor 590. Snare catheters 580, 600 may be used to deliver the anchor 590. The snare catheter may ride over the helical anchor 500 as it slides around the edge of the loop 84. The operator may loosen the snare and then move the snare catheter 580, 600 relative to the helical anchor 500 using imaging such as fluoroscopy, echocardiogram, MR or CT. This will cause the snare catheter 580, 600 to move towards the correct position, such as the junction 80. The amount of loosening of the snares 580, 600 can be adjusted to the desired position to deploy the anchor 590. For example, if the gap between the helical anchor 500 and the joint is 5mm, the operator may decide to position the anchor 590 about halfway between the helical anchor 500 and the joint 80, i.e., about 2.5mm from the outside of the helical anchor 500. This measure is visible through the imaging system. The anchor 590 can be delivered to one leaflet 38 or 42 and then to the other leaflet 38 or 42. The leaflets 38, 42 are then accessible.
If the gap at the junction 80 is large, or if the gap between the leaflets 38, 42 is not successfully closed when the first pair of anchors 590 are implanted, it may also be advantageous to plication the leaflets 38, 42 at more than one point. If the leaflet closure does not successfully close on itself, the plication of the ring 84 toward the leaflets 38, 42 can be very beneficial in preventing leakage. This can be accomplished simply by placing the anchor 590 within the ring 84 at or near the commissures 80 and coapting it along with the anchor 590 to the leaflets 38, 42.
There are many ways to design the leaflets 38, 42 to be in proximity. Clip clips have been created by Abbott's Valve. The anchors do not necessarily need to pierce the leaflet tissue. Non-through anchors may also be used in the above-described procedures. Various anchors have been described by Edwards for their edge-to-edge leaflet repair, initiated by Italian surgeon Ottavio Alfieri. Mitrilign has disclosed the use of anchors within the loop. Any of these anchors, or any suitable anchor, may be used to accomplish the task of closing the junction and preventing paravalvular leakage.
These options are described to indicate that some systems, devices, and methods may be used to approximate leaflet and annulus tissue. Any of these devices and methods may be integrated with the delivery system. The anchor 590 may be carried on the helical anchor 500 or carried by the snare delivery catheter 580, 600.
It is also possible to make the annulus 84 to pleat to the leaflets 38, 42. The anchor 590 may be placed into the annulus 84 and leaflets 38, 42 to form a "triangular" closure to the commissures 80 and prevent leakage.
Leakage may occur at locations other than the joint 80. For example, there is typically a gap or space between the leaflets 38, 42. These cracks can cause leakage. The helical anchor 500 can be used to introduce the anchor 590 to any location that would benefit from access around the helical anchor 500.
It is also possible that the one or portions of the leaflets 38, 42 are not fully positioned within the helical anchor 500. The methods, systems, and devices shown herein can be used to prevent and eliminate leaks. For example, the gap is creased by folding sections of the leaflets 38, 42 together. Tampons or tampons of textile material (polyester, dacron, teflon) may be used (as described above).
It may also be useful to combine leaflets, rings and occluders. All of which may be integrated with the helical anchor 500 and snare catheters 580, 600. The use of concentric coils in a plane below leaflets 38, 42 or above leaflets 38, 42, wherein the coils lie in a single plane parallel to mitral valve 44, can also help close mitral valve leaflets 38, 42 and prevent valve leakage.
Fig. 34E shows plications performed with a catheter 592 introduced from the ventricular side of the valve 44. It will be apparent that the leaflets 38, 42, commissures 80, or annulus 84 may also be pleated from the atrial approach.
The delivery of the anchor is also shown with a relatively straight catheter 592. The conduit 592 can have other shapes, such as a J-shape. The J-shape will allow the anchor 590 from the opposite side of the leaflet 38 or 42 to be delivered from the catheter entry side. For example, a catheter with a J-shaped tip may be delivered from the apex of the left ventricle and guided into the left atrium 46. The anchor 590 may then be delivered from the atrium 46 into the leaflet 38 or 42 toward the ventricle 10.
The snare catheter does not necessarily have to deliver an anchor 590. A separate anchor delivery catheter may be used. It may be attached to the helical anchor 500 or to a snare catheter. A double lumen catheter may be suitable for this purpose. One lumen of the snare delivery catheter may provide attachment to the helical anchor. The other may be used to deliver leaflet folds. There may be a gap between the ends of the two lumens of the dual lumen catheter or dual catheter system. For example, a gap of 2.5mm between the lumens may be advantageous to provide a fold that is 2.5mm from the edge of the helical anchor. As the case may be, a number of fixed gaps are available. For example, if the gap at the junction can be 7mm, a catheter with a 3.5mm gap can be prepared. Alternatively, there is an adjustable gap between the ends of the two lumens to allow for various anatomical conditions. The gap may be adjusted by pulling on the end of one of the catheter ends, or the end may be made to turn completely around. The steering system may allow both lumens to be held at a fixed distance, but the entire catheter may be steered by the operator.
The shaft 504b of the coil guide catheter 504 may be a useful marker for the location of the junction 80. An anchor 612 may be delivered to the outside of the shaft 504b of the coil guide catheter 504 between the helix and the junction 80. Another anchor 612 may be delivered to the distal end of the coil guide catheter 504 between the end of the coil guide catheter 504 and the loop 80.
Referring now to fig. 34H and 34I, an apparatus and method for retaining a valve prosthesis 630 in the mitral position of heart 14 is shown. The valve prosthesis 630 is shown prior to placement within the helical anchor 632, the helical anchor 632 having been placed within the mitral valve position in fig. 34H. The valve prosthesis 630 features threads or grooves 634, which threads or grooves 634 correspond to the bends or coils 636 of the helical anchors 632. The valve prosthesis may be otherwise formed as desired, such as described herein. Fig. 34I shows a valve prosthesis 630, which is held by a helical anchor 632, with a slot 634 engaging the helical anchor 632. The mating of coil 636 of anchor 632 and valve prosthesis 630 is very precise over mitral valve leaflets 38, 42, but not so precise where leaflets 38, 42 are secured between coil 636 and prosthesis 630. Thus, slots 634 located below leaflets 38, 42 can be larger to allow for engagement of the leaflet tissue in addition to coils 636. The groove 634 in the prosthesis 630 may be exactly a mirror image of the coil 636. This optimally requires that valve prosthesis 630 delivered to the catheter be precisely positioned (land) or precisely slid, up or down, relative to coil 636 for locking. To increase the chance of a successful non-slip fit occurring, the slot 634 can be made larger in the prosthetic valve 630 to allow for inaccuracies relative to the helical anchor 632 during delivery of the valve prosthesis 630. The groove 634 may form a continuous thread or the groove 634 may be intermittent. For example, one third of the helical anchor 632 engaged with the prosthesis 630 may be sufficient to prevent displacement. The same effect may be achieved by the in-line pattern of the grooves 634 at different levels along the prosthetic mitral valve 630. Coil 636 may engage more randomly but still make a strong connection.
The groove 634 in the prosthetic mitral valve 630 can be much wider than the coil 636 in the helical anchor 632. For example, the two bends of the helical anchor 632 may be located within a single slot 634 in the valve prosthesis 630. This will allow for a more random interaction between the prosthetic valve 630 and the helical anchor 632 in order to create a reliable connection. For preparation, the valve prosthesis 630 may have the shape of the slot into which it is designed, or additional stent or other material may be added to the prosthetic valve structure to create the slot. For example, the stent or collapsible tube may spiral around the edge of the prosthetic mitral valve, forming a groove that engages the coil 636 of the helical anchor 632 when expanded. The slots 634 or ravines (interruptions) may be arranged in any manner, including continuous slots or intermittent slots.
In another embodiment, the prosthetic valve stent can have a protuberance that can collapse where it engages the coil. These features can be adapted to coil to assist in engagement of the prosthetic valve against coil 632. Alternatively, a section of the prosthetic mitral valve stent may be moved outward. A valve made of nitinol may have sections that move slowly outward to create a sandy or uneven surface suitable for positioning of the helical anchor. Alternatively, nitinol stents may be slowly expanded such that expansion results in a pattern of grooves around the stent that more reliably holds the prosthetic valve within the coil. The nitinol stent may be designed to allow its edges to conform to the grooves of the coil.
The helical anchors 632 may extend above or below the prosthetic valve 630 so as to engage the ends of the prosthetic valve 630. The helical anchor 632 may also be modified. Instead of being completely annular, the anchors 632 may have a generally annular design with sections that extend inwardly to engage the prosthetic valve stent 630. The inwardly curved sections may also have an upward or downward bias. Alternatively, the helical anchors 632 can be made in the form of ball chains and chain-like shapes, wherein the balls are capable of interacting within the space of the prosthetic valve holder. Enlarged portions other than collars may also be used.
The surface of the helical anchor 632 or prosthetic valve 630, as well as any component implanted by the present invention (such as a helical anchor, dock, or prosthesis), may include an outer coating or coating for various purposes, such as for friction-promoting purposes and tissue ingrowth purposes. For example, the outer surface may be roughened so as to make slippage or undesirable movement of the implanted component less likely. For example, the implanted component may be roughened by sandblasting or chemically etching the surface thereof. A coating or cladding, such as a sleeve of biocompatible material, may be added. These may include silicone, polyester, polyurethane or any other desired material. The helical anchors of the present invention can have other friction-promoting surfaces and/or tissue ingrowth surfaces that can be comprised of fabric or even nitinol or stainless steel to help engage the prosthetic valve.
The prosthetic valve stent 630 can also be flared at one or both ends. This may be used to prevent upward or downward displacement. Many prosthetic valves are balloon-expandable, so the balloon that expands the stent may have an hourglass shape, or have only one end flared to expand the valve.
When pressurized, the leaflet commissure of the mitral valve leaflets closes. There is generally no serious commissure leak after valve repair because pressure on the leaflets brings their edges together. Any design of these helical anchors can be modified to facilitate closure of the valve annulus by placing the leaflets in the same position as they would have been when the ventricle was pressurized. The coils under the leaflets shown in most of the previous figures are "stacked" on top of each other, i.e. when the mitral valve plane is taken into account, each coil is in a different plane as the coils travel away from the mitral valve.
It is also possible that the coils below the leaflets 38, 42 are concentric, while the coils may be relatively in the same plane below the leaflets. The diameter of each bend may be slightly wider or narrower, with all coils lying substantially in the same plane. This means that the coil will be located directly below the leaflets 38, 42 of the mitral valve 44. By creating a spring force against the annulus 84 or leaflets 38, 42, the leaflets 38, 42 will be urged upward toward their closed position when the ventricle 10 is pressurized upon systole. The spring force may come from coils positioned against the atrial wall 46a on opposite sides of the leaflets 38, 42. The coil may also be biased upward during manufacture (so as to be positioned against the underside of the native mitral valve leaflet) to further facilitate leaflet apposition at the commissures 80. Closure of the commissures 80 is best achieved by a series of concentric coils above the leaflets 38, 42 and below the leaflets 38, 42 arranged to generate a compressive force against the mitral leaflets 38, 42 and close the commissures 80. In this arrangement, the smaller diameter curvature of the coil below the leaflets 38, 42 can retain the prosthetic mitral valve. The larger curve or coil may be closed at the juncture.
For preparation, a helical anchor comprising three concentric bends, each lying in a plane, also works well. When the helical anchor is inserted with two bends under the leaflets and one bend positioned against the atrial wall 46a, the spring force will tend to pull the bends (or loops) of the helical anchor above and below the commissures 80 together and close the commissures 80.
Furthermore, additional coils may simply be added to the helical anchor and pushed into place simply for the operator. The combination of coils that close the joint 80 by applying an upward spring force by the coil holding the prosthetic mitral valve 44 can provide an optimal configuration. The coil below the helical anchor may include a series of coils (coils relatively parallel to the native valve implant) that push the leaflets 38, 42 up to a closed position and coils that hold the leaflets 38, 42 (more perpendicular to the native valve plane). Coiling over the leaflets 38, 42 can hold the leaflets 38, 42 against their atrial side or the atrial wall itself.
The coiling of the closure commissures 80 can be used in conjunction with "occlusion" devices and methods, systems and devices for approximating the leaflets 38, 42 and annulus 84. For example, a coil located below the ring 84 may engage with an occluding or blocking device positioned on the coil in the area of the joint 80.
Referring now to fig. 34J-34L, an alternative embodiment of a helical anchor 650 according to the present invention is shown. As generally noted above, the helical anchor 650 includes a cover 650a, which cover 650a may be a tissue ingrowth surface, such as a cover (e.g., fabric) or coating or sleeve, or simply subjected to a surface treatment. Any of the options described herein may be used to improve the implantation process and/or post-implantation surgery quality. Fig. 34J shows a helical anchor having one bend 652 in the left atrium 46 above the mitral valve 44 where it presses against the atrial wall 46a adjacent the valve 44. As shown in fig. 34K, two curved portions 654, 656 are positioned below the leaflets 38, 42 and press up against the leaflets to pull the edges of the anterior and posterior leaflets 38, 42 together to close the junction 80. This may prevent the quasi-valve from leaking once the prosthetic mitral valve is anchored. Additional coils around the circumference of the helical anchor 650 ensure that the valve prosthesis will be positioned in the center of the anchor 650. It should be noted that it is particularly advantageous when the valve prosthesis is significantly smaller than the native mitral annulus 84 of the patient, as the valve prosthesis would otherwise slide from the anchors and become dislodged. The helical anchor 650 may be positioned flat in one plane prior to insertion into the mitral valve location. Thus, after its implantation, there is a spring force exerted by anchor 650 that pushes mitral valve leaflets 38, 42 together upward. In another embodiment, even greater spring force may be applied if the anchor 650 is configured such that the two bends 654, 656 below the loop 84 are arranged to naturally be positioned higher than the bends or coils 652 shown above the leaflets 38, 42 prior to insertion into the mitral position. During insertion, coils 654, 656 will first be directed to spiral into ventricle 10 and around chords 48, and the final coil or coils 652 will be delivered to the upper side of valve 44. Because the lower coils 654, 656 will move toward their normal position (which is above coil 652), there will be a compressive force exerted upward (as viewed in fig. 34J) by the coils 654, 656. Fig. 34L is a cross-section taken along line 34L-34L of fig. 34K, illustrating the upward force exerted by the lower coils 654, 656 on the mitral leaflets 38, 42. A portion of the second coil 660 of the anchor is shown above the loop 84.
Appendix a is attached and forms part of this specification. Appendix a is a catalog of prototypes 1-8 showing examples of helical anchors constructed in accordance with embodiments of the present invention and used for the parking of mitral valve prostheses as described herein. Each prototype helical anchor is represented by respective top and side view photographs after implantation and schematic cross-sectional side views of the helical coil structure relative to the anterior and posterior mitral leaflets (represented by downwardly curved lines).
In other embodiments involving helical anchors, alternative configurations may be used in accordance with the present invention. For example, some coils of the helical anchor above the leaflets 38, 42 can be placed in contact with the leaflets 38, 42, and some coils of the helical anchor above the leaflets 38, 42 can be placed in contact with the atrial wall 46 a. The number of coils and the order of contact may vary. For example, the coil may be replaced between contacting leaflets 38, 42 and contacting atrial wall 46 a. Alternatively, some coils of the helical anchor above the leaflets may hold the valve prosthesis out of contact with the leaflets 38, 42, while some coils above the leaflets 38, 42 may be placed in contact with the atrial wall. The coil contacting the atrial wall 46a may pass upwardly away from the mitral valve 44 or downwardly into contact with the atrial wall 46a adjacent the mitral valve 44. In one embodiment, the coils may be passed down so that they contact the outside of the coils holding the valve prosthesis, forming a double coil. Advantages of the dual coils include improved structural strength of the helical anchor and reduced risk of coil thrombosis or embolism.
In another embodiment involving a helical anchor, the coil of the anchor may be the carrier for the occlusion device. For example, a fabric tampon or occluding device may be wound onto a coil and moved to any location where leakage may occur. Plugging material may also be positioned between the coils. The previously described apparatus, systems, and methods for bringing together anterior and posterior leaflets may be used in conjunction with such blockage to provide improved leakage resistance.
In other embodiments, devices and systems as described may be introduced from the atrium 46, ventricle 10, or aorta 18 using an open heart or puncture approach or delivered from a catheter into the left atrium 46 or retrograde into the left ventricle 10 from the aortic valve 22. Similarly, the system may be introduced into the atrium 46 in an open chest or percutaneously into the atrium 46 via the apex 6 by means of an apex occluder. Alternatively, introduction may be by other means, for example, through a minimal incision in heart 14 and/or an endoscope.
In addition, the devices and systems described above may be introduced using a route that is partially or completely through the aorta 18. The coil guide catheter or delivery catheter may be fed to the aortic valve 22 from any peripheral location (e.g., groin, shoulder area or arm/wrist) or a central aortic location. All of these access routes are typically used clinically to access the aortic valve 22 and the coronary arteries. A coil guide catheter or delivery catheter may then be fed through the aortic valve 22 into the left ventricle 10. Any of the above-described devices, systems and methods may be used to implant the mitral valve prosthesis using a route from the left ventricle 10. The assisting tools described herein (e.g., snare catheters, grasping tools, etc.) may also be introduced via the aorta 18. Any route of helical anchor or stent dock delivery (e.g., transseptal, transventricular, transatrial) may be used in conjunction with any route of valve delivery (e.g., transseptal, transventricular, transatrial).
In one embodiment, the grasping tool can be connected to the end of the helical anchor by a suture or thread. The suture or threads may comprise a plastic material, such as polypropylene, which is commonly used in sutures, or other synthetic materials, such as polyester, which are often woven into sutures. The suture couples the grasping tool to the end of the helical anchor by sliding through a hole in the grasping tool and guiding it to the end of the anchor. At the end of the procedure, the suture may be cut. The grasping tool may have an integrated scissors for this purpose or the suture may be trimmed with a separate tool. In another embodiment, the suture may be wrapped over the end of the helical anchor and released by dragging. The end of the helical anchor, which preferably features an enlarged spherical shape, may comprise a hole for passage of a suture, wherein the suture may be held by crimping (crimping) or gluing. After the procedure, the suture may be cut or pulled out. A useful strategy for removing the suture with the grasping tool is to slide the grasping tool over the suture so that it is at the end of the ball. The grasping tool is then rotated to jerk the suture from the interior of the ball so that it can be removed. It is also desirable to avoid a rigid connection or link between the grasping tool and the end of the helical anchor and to avoid the use of sutures. Conversely, a pivotable joint such as a universal joint may be desirable.
There are some important dimensions to consider for a coiled guide catheter. The first dimension is the distance between the distal tip of the introducer and the shaft or straight portion of the introducer and the shaft. This distance may be constructed to be approximately equal to the diameter of the mitral annulus or the distance between the junctions, so that when the shaft of the coil guide catheter is guided through one junction, the distal tip of the coil guide catheter will rest at the other junction. This means that the grasping tool will also pass through the mitral valve at the junction opposite the stem, so that the system is centered within the valve. Furthermore, a well-defined orientation is provided for the starting point of the anchor delivery relative to the mitral valve leaflet. The tip of the coil guide catheter is close to the junction to ensure that the junction receives the start of the helical anchor. The commissures of the mitral valve are relatively easily identifiable on the echocardiogram so that the shaft and grasping tool of the coiled guide catheter can be identified to pass through the relative commissures of the mitral valve. By using the anatomical landmark, the operator can ensure that he or she pushes the helical anchor under the mitral valve leaflet at the junction. This simple relationship can make proper placement of the anchor relatively easy. If the rod and grasping tool do not pass the junction, the coil guide catheter may be rotated until they pass the junction. It will be appreciated that orientation at the ring is not necessarily required. Any point along the valve may be chosen, but the commissures are particularly easy to identify by non-invasive imaging. If the operator wishes to introduce the anchor at a point other than the commissures, the position of the rod and grasping tool relative to the mitral annulus can be compared to the valve in order to correctly position the anchor's entry point.
Another important dimension for the coil guide catheter is the distance from the widest point of the bend to the line joining the tip of the coil guide catheter to the distal tip of the shaft of the coil guide catheter. The dimensions may be adjusted so that the curved portion of the coil guide catheter (which generally or approximately follows the path of the mitral annulus) is located beyond the end of the native mitral valve at the base of the heart. The operator may then place the coil guide catheter in place at the junction within the heart with the aid of echocardiographic guidance, and then pull the coil guide catheter back until it is flush against the left atrial wall. This provides tactile positioning to the operator and allows the depth of the coiled guide catheter to be precisely adjusted. Visually, such as by fluoroscopy or echocardiography, a stop is identified by a slight movement of the coil guide catheter when it hits the atrial wall. Since the left atrium has a slight upward curvature, the upward curvature of the coil guide catheter on this curvature may facilitate following the shape of the heart as it passes away from the native mitral valve.
While the present invention has been illustrated by a description of preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The various features and concepts of the invention may be used alone or in any combination depending on the needs and preferences of the operator. This is a description of the invention, along with the preferred methods of practicing the invention as currently known. The invention itself, however, should be limited only by the attached claims.