US20050148997A1 - Methods and apparatus for anchoring an occluding member - Google Patents

Abstract

Pressure is measured on both sides of an occluding member for determining when pressure forces on the occluding member may cause migration of the occluding member. An alarm indicates when the pressure force on the balloon exceed a predetermined threshold. In another aspect of the invention, a pressure monitor determines when a rate of pressure increase with respect to the fluid volume in the balloon reaches a predetermined threshold when inflating the occluding member. A predetermined amount of fluid is then added to the balloon so that the balloon is not under inflated or over inflated.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of U.S. patent application Ser. No. 08/570,286, filed Dec. 11, 1995, which is a continuation-in-part of Ser. No. 08/486,216, filed Jun. 7, 1995 which is a continuation-in-part of application of copending U.S. patent application Ser. No. 08/282,192, filed Jul. 28, 1994, which is a continuation-in-part of application Ser. No. 08/162,742, filed Dec. 3, 1993, which is a continuation-in-part of application Ser. No. 08/123,411, filed Sep. 17, 1993, which is a continuation-in-part of application Ser. No. 07/991,188, filed Dec. 15, 1992, which is a continuation-in-part of application Ser. No. 07/730,559, filed Jul. 16, 1991, which issued as U.S. Pat. No. 5,370,685 on Dec. 6, 1994. This application is also related to copending U.S. patent application Ser. No. 08/159,815, filed Nov. 30, 1993, which is a U.S. counterpart of Australian Patent Application No. PL 6170, filed Dec. 3, 1992. This application is also related to copending U.S. patent application Ser. No. 08/281, 962, filed Jul. 28, 1994, which is a continuation-in-part of application Ser. No. 08/163,241, filed Dec. 6, 1993, which is a continuation-in-part of application Ser. No. 08/023,778, filed Feb. 22, 1993. This application is also related to copending U.S. patent application Ser. No. 08/281,981, filed Jul. 28, 1994, which is a continuation-in-part of application Ser. No. 08/023,778, filed Feb. 22, 1993. This application is also related to copending U.S. patent application Ser. No. 08/213,760, filed Mar. 16, 1994. The complete disclosures of all of the aforementioned related U.S. patent applications are hereby incorporated herein by reference for all purposes.
FIELD OF THE INVENTION
• The present invention is directed to apparatus and methods for reducing migration of occlusion members. A specific application of the invention is described in conjunction with devices and methods for temporarily inducing cardioplegic arrest in the heart of a patient and for establishing cardiopulmonary bypass in order to facilitate surgical procedures on the heart and blood vessels.
BACKGROUND OF THE INVENTION
• Various cardiovascular, neurosurgical, pulmonary and other interventional procedures, including repair or replacement of aortic, mitral and other heart valves, repair of septal defects, congenital defect repairs, pulmonary thrombectomy, coronary artery bypass grafting, angioplasty, atherectomy, treatment of aneurysms, electrophysiological mapping and ablation, and neurovascular procedures, may require general anesthesia, cardiopulmonary bypass, and arrest of cardiac function. In such procedures, the heart and coronary blood vessels are isolated from the remainder of the circulatory system. This serves several purposes. First, such isolation facilitates infusion of cardioplegic fluid into the coronary arteries to perfuse the myocardium and arrest cardiac function without allowing the cardioplegic fluid to be distributed elsewhere in the patient's circulatory system. Second, such isolation facilitates use of a cardiopulmonary bypass system to maintain circulation of oxygenated blood throughout the circulatory system without allowing such blood to reach the coronary arteries and resuscitate the heart. Third, in cardiac procedures, such isolation creates a working space into which the flow of blood and other fluids can be controlled or prevented so as to create an optimum surgical environment.
• One medical procedure of particular interest to the present invention is the treatment of heart valve disease. Co-owned, copending patent application Ser. No. 08/281, 962 and Ser. No. 08/486,216, which are incorporated herein by reference, describe methods of performing closed-chest or thoracoscopic heart valve replacement surgery. Isolating the heart from the systemic blood circulation, inducing cardioplegic arrest and establishing cardiopulmonary bypass are important steps in the performance of the heart valve replacement procedure.
• The endovascular system includes an elongated aortic partitioning catheter having an occluding member on a distal portion of the catheter adapted to occlude a patient's ascending aorta. The catheter preferably has an inner lumen extending within the catheter to a port in the distal end of the catheter. The catheter is adapted to be inserted into the patient's arterial system (e.g. through the femoral or brachial arteries) and advanced to the ascending aorta where the occluding member is expanded to occlude the aorta. The occluding member separates the left ventricle of the heart and an upstream portion of the ascending aorta from the rest of the patient's arterial system. Thus, the catheter provides an endovascularly inserted, internal vascular clamp, similar in function to the external “cross-clamp” used in open cardiac surgical procedures. The internal clamp is less traumatic to the clamped vessel and provides a lumen or working channel through which instruments or fluids may be passed into or withdrawn from the area upstream of the distal end of the clamp.
• Also included with the system is a cardiopulmonary bypass system which withdraws blood from the patient's venous system, e.g. the femoral or jugular vein, removes CO₂and adds oxygen to the withdrawn blood, and returns the oxygenated blood to the patient's arterial system, e.g. the femoral or brachial artery. The system is also provided with a device for infusing fluid containing cardioplegic material (e.g. an aqueous solution of KCl and/or magnesium procaine and the like) through the coronary arteries so as to temporarily paralyze the myocardium.
• A preferred method for inducing cardioplegic arrest of a heart in situ in a patient's body, includes the steps of:
• (a) maintaining systemic circulation with peripheral cardiopulmonary bypass;
• (b) partitioning the coronary arteries from the ascending aorta by, e.g., occluding the ascending aorta through a percutaneously placed arterial balloon catheter;
• (c) introducing a cardioplegic agent into the coronary circulation; and
• (d) venting the heart.
• The method may be carried out on humans or other mammalian animals. The method is of particular applicability in humans as it allows an alternative approach to open heart surgery and the development of closed cardioscopic surgery. The method enables a percutaneous bypass system to be associated with cardioplegia, venting and cooling of the heart which overcomes the need for a median sternotomy.
• In a preferred embodiment, the occluding member is an inflatable cuff or balloon of sufficient size to occlude the ascending aorta. The length of the balloon should preferably not be so long as to impede the flow of blood or other solution to the coronary arteries or to the brachiocephalic, left carotid or left subclavian arteries. A balloon length of about 20-40 mm and diameter of about 35 mm is suitable in humans. The balloon may be cylindrical, spherical, ellipsoidal or any other appropriate shape to fully and evenly accommodate the lumen of the ascending aorta. This maximizes the surface area contact with the aorta, and allows for even distribution of occlusive pressure.
• The balloon is preferably inflated with a saline solution mixed with a radiopaque contrast agent to avoid introducing an air embolism if the balloon ruptures. The balloon should be inflated to a pressure sufficient to prevent regurgitation of blood into the aortic root and to prevent migration of the balloon into the root whilst not being so high as to damage the aorta. An intermediate pressure of about 350 mm Hg, for example, is preferred.
• The aortic partitioning catheter is preferably introduced under fluoroscopic guidance over a guidewire. Transoesophageal echocardiography can also be used for positioning the aortic catheter. The catheter may serve a number of separate functions and the number of lumina in the catheter will depend upon how many of those functions the catheter is to serve. The catheter can be used to introduce the cardioplegic agent, normally in solution, into the aortic root via one lumen. The luminal diameter will preferably be such that a flow of the order of 100-500 ml/min of cardioplegic solution, and more preferably 250-500 ml/min, can be introduced into the aortic root under positive pressure to perfuse the heart by way of the coronary arteries. The same lumen can, by applying negative pressure to the lumen from an outside source, effectively vent the left heart of blood or other solutions. The cardioplegic agent may be any known cardioplegic agent. The agent is preferably infused as a solution into the aortic root through one of the lumina of the aortic catheter.
• It may also be desirable to introduce medical instruments and/or a cardioscope into the heart through another lumen in the catheter. The lumen should be of a diameter suitable to pass a fiberoptic light camera of no greater than 3 mm diameter. It is, however, preferable that the diameter and cross-section of the internal lumina are such that the external diameter of the catheter is small enough for introduction into the adult femoral artery by either percutaneous puncture or direct cutdown.
• The oxygenated blood returning to the body from the bypass system is conveyed into the aorta from another lumen in the cannula carrying the balloon. In this case, the returning blood is preferably discarded from the catheter in the external iliac artery. In another embodiment of the invention, and in order to reduce the diameter of the catheter carrying the balloon, a separate arterial catheter of known type may be used to return blood to the patient from the bypass system. In this case a short catheter is positioned in the other femoral artery to provide systemic arterial blood from the bypass system. The control end of the catheter, i.e. the end that remains outside the body, should have separate ports of attachment for the lumina. The catheter length should be approximately 900 mm for use in humans.
• With the heart paralyzed, the expandable member is expanded within the ascending aorta, and with the cardiopulmonary bypass operating, the heart is prepared for a cardiac procedure. While a particularly attractive feature of the invention is that it prepares the heart for endovascular, thoracoscopic, and other minimally-invasive procedures, the invention can also be used to prepare the heart for conventional open-heart surgery via a thoracotomy. It should also be noted that, if during an endovascular cardiac procedure in accordance with the invention, it becomes necessary to perform an open-heart procedure, the patient is already fully prepared for the open-heart procedure. All that is necessary is to perform a median sternotomy to expose the patient's heart for the conventional surgical procedure.
• The endovascular device for partitioning the ascending aorta between the coronary ostia and the brachiocephalic artery preferably includes a flexible shaft having a distal end, a proximal end, and a first lumen therebetween with an opening at the distal end in communication with the first lumen. The shaft has a distal portion which is shaped for positioning in the aortic arch so that the distal end is disposed in the ascending aorta pointing toward the aortic valve. The first lumen may be used to withdraw blood or other fluids from the ascending aorta, to introduce cardioplegic fluid into the coronary arteries for paralyzing the myocardium, and/or to introduce, surgical instruments into the ascending aorta, the coronary arteries, or the heart for performing cardiac procedures.
• In one embodiment, the distal portion is shaped so that the distal end of the shaft is spaced apart from any interior wall of the aorta and the distal end is aligned with the center of the aortic valve. By “shaped,” it is meant that the distal portion of the shaft is preset in a permanent, usually curved or bent shape in an unstressed condition to facilitate positioning the distal portion within at least a portion of the aortic arch. A shaft is preferably for straightening the preshaped distal portion. Usually, the straightening means comprises a straightening element slidably disposed in the first inner lumen having a stiffness greater than the stiffness of the preshaped distal portion. The straightening element may comprise a relatively stiff portion of a flexible guidewire extending through the first inner lumen, or a stylet having an axial passage through it for receiving a movable guidewire. Although it is preferred to provide a shaped-end and a straightener, the shaped-end may be imparted to the distal portion of the shaft with a shaping or deflecting element positioned over or within the shaft.
• The balloon may be made of an elastomeric material, such as polyurethane, silicone or latex. In other embodiments, the occlusion means may be an inflatable balloon made of a nondistensible balloon material, such as polyethylene, polyethylene terephthalate polyester, polyester copolymers, polyamide or polyamide copolymers. The balloon is further configured to maximize contact with the aortic wall to resist displacement and prevent leakage around the balloon, preferably having a working surface for contacting the aortic wall with a length in the range of about 1 to about 7 cm, more preferably in the range of about 2 to 5 cm, when the balloon is expanded to fully occlude the vessel.
• When a balloon is used for the occluding means, the endovascular device has an inflation lumen extending through the shaft from the proximal end to the interior of the balloon, and means connected to the proximal end of the inflation lumen for delivering an inflation fluid to the interior of the balloon.
• The shaft of the endovascular device may have a variety of configurations. The first inner lumen and inflation lumen may be coaxial, or a multilumen design may be employed. The shaft may further include a third lumen extending from the proximal end to the distal end of the shaft, allowing pressure distal to the occluding means to be measured through the third lumen. The shaft may also include means for maintaining the transverse dimensions of the first inner lumen, which may comprise a wire coil or braid embedded in at least the distal portion of the shaft to develop radial rigidity without loss of longitudinal flexibility. The shaft preferably has a soft tip at its distal end to prevent damage to the heart valve if the catheter comes into contact with the delicate valve leaflets.
• The shaft preferably has a length of at least about 80 cm, usually about 90-125 cm, to allow transluminal positioning of the shaft from the femoral and iliac arteries to the ascending aorta. Alternatively, the shaft may have a shorter length, e.g. 20-60 cm, for introduction through the iliac artery, through the brachial artery, through the carotid artery, or through a penetration in the aorta itself.
• The shaped distal portion of the device maintains the distal end in a position spaced apart from the interior wall of the ascending aorta so that the distal opening is unobstructed and generally aligned with the center of the aortic valve. This facilitates aspiration of blood, other fluids, or debris, infusion of fluids, or introduction of instruments through the distal opening in the endovascular device without interference with the aortic wall or aortic valve tissue. The method may further include, before the step of introducing the shaft into the blood vessel, the steps of determining a size of the patient's aortic arch, and selecting a shaft having a shaped distal portion corresponding to the dimensions and geometry of the aortic arch.
• Thus, using the aforementioned system and method, a patient's heart can be arrested and the patient placed on cardiopulmonary bypass without a thoracotomy, thereby reducing mortality and morbidity, decreasing patient suffering, reducing hospitalization and recovery time, and lowering medical costs relative to open-chest procedures. The endovascular partitioning permits blood flow through the ascending aorta to be completely blocked between the coronary ostia and the brachiocephalic artery in order to isolate the heart and coronary arteries from the remainder of the arterial system. This has significant advantages over the aortic cross-clamps used in current cardiac procedures, not only obviating the need for a thoracotomy, but providing the ability to stop blood flow through the aorta even when calcification or other complications would make the use of an external cross-clamp undesirable.
• The system and method may further be useful to provide cardiopulmonary bypass during endovascular interventional procedures in which cardiac function may or may not be arrested. Such procedures may include angioplasty, atherectomy, heart valve repair and replacement, septal defect repair, treatment of aneurysms, myocardial mapping and ablation, myocardial drilling, and a variety of other procedures wherein endovascular interventional devices are introduced through the bypass cannula of the invention and advanced into the heart or great vessels. In this way, the invention facilitates cardiopulmonary bypass during such procedures without requiring additional arterial or venous penetrations.
• The aforementioned applications and patents describe an endovascularly positionable occluding member which is used to occlude the ascending aorta of the patient. Because of its proximity to the left ventricle, the occluding member is subject to pressure forces on both sides of the balloon. Pressure forces are developed, for example, from the outflow of blood during systole. Such forces threaten to displace the occluding means either downstream, where it might occlude the ostium of the brachiocephalic or other artery, or upstream where the occluding member might damage the aortic valve or occlude the coronary ostia. Advantageously, the shape of the distal end of the endovascular device described above is configured to help maintain the position of the occluding member in the ascending aorta against the force of systolic outflow as the occluding member is expanded and retracted, as well as during the period in which the occluding member fully occludes the aorta but the heart remains beating.
• Although the shaped distal end of the above-described endovascular occluding member helps to prevent migration of the occluding member, further features which reduce migration are desirable given the potentially catastrophic consequences of occluding member migration.
SUMMARY OF THE INVENTION
• The present invention is directed to methods and devices for anchoring an occluding member in a patient. A specific application of the invention is described with respect to a method and system for an endovascular approach for preparing a patient's heart for cardiac procedures which does not require a grossly invasive thoracotomy.
• In an aspect of the present invention, the occluding member is a balloon having surface features which enhance the frictional engagement between the balloon and the aorta. The balloon preferably includes an outer surface having a first portion with a higher coefficient of friction than a second portion relative to the occluded body part. The first portion preferably includes a number of short ribs but may include any other surface feature including radial ribs, spiral ribs, cross-hatching, knobs, a frictional coating or any other surface feature so long as the first portion has a higher coefficient of friction than the second portion relative to the occluded body part. Although it is preferred to enhance the frictional engagement of the first portion, it is also within the scope of the invention to decrease the frictional engagement between the second portion and the occluded body part to achieve the same desired difference in frictional engagement.
• The second low-friction portion is preferably positioned at a radially outward position relative to the first portion so that when the balloon is advanced within the patient substantially only the low friction portion contacts the body passageway. The balloon preferably includes a number of low friction portions which are positioned at radially outward portions of at least three, and preferably at least four, arms. The high friction portion is positioned between adjacent low friction portions and, further, the high friction everts when the balloon moves from the collapsed shape to the expanded shape. The term “collapsed” as used herein refers to the overall configuration of the expandable member when the expandable member is advanced within the patient to the desired occluding position. An advantage of the present invention is that the first, high-friction portion does not contact the body passageway when the balloon is advanced within the patient thereby reducing trauma and, furthermore, reducing the risk of releasing plaque into the bloodstream.
• The first portion is preferably integrally formed with the second portion and is provided with a number of ribs and/or a selective coating. A method of providing a selective coating and other methods of providing a frictional surface are described in PCT Application Number PCT/US94/09489 which is incorporated herein by reference. Another method of providing high and low friction portions would be to mask the low friction portion and sandblast the high friction portion. Alternatively, a mandrel which is used to make the balloon may have the high friction portion sandblasted.
• The present invention provides distinct advantages over PCT Application Number PCT/US94/09489 since the radially-extending arms help prevent the high friction portions from contacting the blood vessel. A problem which might occur with the balloon of PCT/US94/09489 is that the balloon might unravel when the balloon is inserted into the patient thereby exposing the high friction portions. Conversely, if the balloon is wrapped too tight, the balloon may not open correctly when the balloon is inflated. The present invention provides high friction portions which are exposed but prevented from contacting the body passageway by the radially outward portion of the arms.
• In another aspect of the invention, pressure sensors are provided on both sides of the balloon for measuring pressures exerted on the balloon. In this manner, it can be determined when a pressure differential exists across the expandable member which might move the balloon upstream or downstream. The pressure sensors are preferably coupled to an alarm which indicates when the pressure differential exceeds a predetermined threshold pressure. In a preferred embodiment, the pressure of cardioplegic fluid in the ascending aorta is adjusted to reduce the pressure differential to a value below the threshold pressure. The descriptive terms downstream and upstream refer to the direction of blood flow and the direction opposite normal blood flow, respectively. In the arterial system, downstream refers to the direction away from the heart and upstream refers to the direction toward to the heart. The terms proximal and distal, when used herein in relation to instruments used in the procedure, refer to directions closer to and farther away from the operator performing the procedure, respectively.
• In another aspect of the invention, the pressure of the balloon is monitored to optimize the inflation pressure. When inflating the balloon, it is desirable to provide a high pressure so that the balloon holding force is maximized to prevent migration. On the other hand, it is desirable to minimize balloon pressure so that aortic distention is minimized. In order to provide a balloon pressure which balances these two concerns the balloon pressure is monitored until a spike in the pressure vs. fluid volume is detected. The pressure spike generally indicates that the balloon has engaged the sidewall of the passageway. After the pressure spike is detected, a predetermined amount of fluid is added or the pressure of the balloon is increased a predetermined amount so that the balloon pressure is optimized to enhance the holding force on the balloon while preventing excessive aortic distention.
• In yet another aspect of the invention, the shaft of the catheter is displaced and anchored so that a portion of the shaft engages the aortic lumen for resisting balloon migration. The shaft is preferably slidably coupled to a delivery cannula for movement in both inward and outward directions. The shaft preferably includes a first portion configured to contact the radially inner wall of the aortic lumen when the shaft is slidably displaced in the outward direction. The first portion anchors the shaft which, in turn, anchors the occluding member. When the shaft is displaced in the inward direction, a second portion engages the radially outer wall of the aortic lumen. A preferred shape for the shaft includes two bends and three substantially straight portions. The first predetermined portion, which engages the radially inward wall of the aorta, is preferably positioned between the first and second bends.
• In yet another aspect of the invention, an external clamp is clamped near the occluded region to prevent migration of the occluding member. The clamp may be positioned on one or both sides of the occluding member. Alternatively, the clamp may be positioned around the occluding member to prevent migration in both directions.
• A still further aspect of the invention provides an anchor which extends into the brachiocephalic artery for preventing upstream migration of an occluding member positioned in the ascending aorta between the coronary ostia and the brachiocephalic artery. The anchor is preferably a perfusion catheter configured to deliver oxygenated blood to the brachiocephalic artery. The anchor is preferably separate catheter but may also be integrally formed with the occluding member catheter.
• These and other advantages of the invention will become apparent from the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 schematically illustrates a cardiac access system employing the endoaortic partitioning catheter of the present invention.
• FIG. 2 is a schematic partly cut-away representation of a patient's heart with the endoaortic partitioning catheter of the present invention placed within the ascending aorta.
• FIG. 3 is a transverse cross-sectional view of the occluding catheter shown inFIG. 2 taken along the lines3-3.
• FIG. 4. is an enlarged view, partially in section, of the retrograde cardioplegia delivery catheter and the pulmonary venting catheter shown inFIG. 1.
• FIG. 5A is a longitudinal cross section of a first embodiment of the endoaortic partitioning catheter of the present invention.FIG. 5B is a lateral cross section of the catheter ofFIG. 5A taken along thelines5B-5B.FIG. 5C is a lateral cross section of the catheter ofFIG. 5A taken along thelines5C-5C.FIG. 5D is a detail drawing showing the construction ofsection5D-5D of the catheter ofFIG. 5A.
• FIG. 6A is a lateral side view of a second embodiment of the endoaortic partitioning catheter.FIG. 6B is a lateral cross section of the catheter ofFIG. 6A taken along thelines6B-6B.FIG. 6C is a lateral cross section of the catheter ofFIG. 6A taken along thelines6C-6C.
• FIG. 7A is a longitudinal cross section of a third embodiment of the endoaortic partitioning catheter having piezoelectric pressure transducers.FIG. 7B is a lateral cross section of the catheter ofFIG. 7A taken along the lines7B-7B.FIG. 7C is a lateral cross section of the catheter ofFIG. 7A taken along thelines7C-7C.
• FIG. 8A is a longitudinal cross section of a fourth embodiment of the endoaortic partitioning catheter having a variable length occlusion balloon with the occlusion balloon deflated.FIG. 8B is a longitudinal cross section of the catheter ofFIG. 8A with the occlusion balloon inflated in an elongated position.FIG. 8C is a longitudinal cross section of the catheter ofFIG. 8A with the occlusion balloon inflated in a shortened position.FIG. 8D shows the proximal end of an alternate embodiment of the catheter ofFIG. 8A.
• FIG. 9A is a side view, partially in section, of a fifth embodiment of the endoaortic partitioning catheter having a twisted low-profile occlusion balloon.FIG. 9B is a longitudinal cross section of the catheter ofFIG. 9A with the occlusion balloon inflated.
• FIG. 10A is a front view of a sixth embodiment of the endoaortic partitioning catheter having a precurved distal end.FIG. 10B is a side view of the catheter ofFIG. 10A.FIG. 10C is a lateral cross section of the catheter ofFIG. 10A taken along the lines10C-10C.
• FIG. 11 is a schematic partly cut-away representation of a patient's aortic arch with the endoaortic partitioning catheter ofFIG. 10A positioned in the ascending aorta.
• FIG. 12A is a front view of a seventh embodiment of the endoaortic partitioning catheter having a precurved distal end.FIG. 12B is a side view of the catheter ofFIG. 12A.FIG. 12C is a lateral cross section of the catheter ofFIG. 12A taken along the lines12C-12C.
• FIG. 13 is a schematic partly cut-away representation of a patient's aortic arch with the endoaortic partitioning catheter ofFIG. 12A positioned in the ascending aorta.
• FIG. 14 is a front view of an eighth embodiment of the endoaortic partitioning catheter having an eccentric aortic occlusion balloon.
• FIG. 15 is a schematic partly cut-away representation of a patient's aortic arch with an endoaortic partitioning catheter having a concentric occlusion balloon positioned in the ascending aorta.
• FIG. 16 is a schematic partly cut-away representation of a patient's aortic arch with an endoaortic partitioning catheter having an eccentric occlusion balloon positioned in the ascending aorta.
• FIG. 17 is a front view of an ninth embodiment of the endoaortic partitioning catheter having an eccentric aortic occlusion balloon.
• FIG. 18A is a front view of a tenth embodiment of the endoaortic partitioning catheter having an eccentric aortic occlusion balloon.FIG. 18B is an end view of the catheter ofFIG. 18A.
• FIG. 19A is a front view of an eleventh embodiment of the endoaortic partitioning catheter having a nondistensible aortic occlusion balloon.FIG. 19B is an end view of the catheter ofFIG. 19A.FIG. 19C is a side view of the catheter ofFIG. 19A with the occlusion balloon wrapped around the catheter shaft.FIG. 19D is an end view of the catheter ofFIG. 19C.
• FIG. 20A is a front view of a twelfth embodiment of the endoaortic partitioning catheter having a nondistensible aortic occlusion balloon.FIG. 20B is an end view of the catheter ofFIG. 20A.FIG. 20C is a side view of the catheter ofFIG. 20A with the occlusion balloon wrapped around the catheter shaft.FIG. 20D is an end view of the catheter ofFIG. 20C.
• FIG. 21 is a schematic partly cut-away representation of a patient's aortic arch with an endoaortic partitioning catheter having a shaped occlusion balloon positioned in the ascending aorta.
• FIG. 22 is a schematic partly cut-away representation of a patient's aortic arch with an endoaortic partitioning catheter having a shaped occlusion balloon positioned in the ascending aorta.
• FIG. 23A is a schematic partly cut-away representation of a patient's aortic arch with an endoaortic partitioning catheter having a shaped occlusion balloon positioned in the ascending aorta.FIG. 23B is a transverse cross section of the shaped occlusion balloon ofFIG. 23A.
• FIG. 24 is a schematic partly cut-away representation of a patient's aortic arch with an endoaortic partitioning catheter having a shaped occlusion balloon positioned at the apex of the aortic arch.
• FIG. 25A illustrates an endoaortic partitioning catheter with a curved tip for de-airing the heart and ascending aorta.FIG. 25B illustrates an alternate embodiment of an endoaortic partitioning catheter for de-airing the heart and ascending aorta.
• FIG. 26 illustrates an endoaortic partitioning catheter having a dumbbell-shaped occlusion balloon for centering the catheter tip within the ascending aorta.
• FIG. 27 illustrates an endoaortic partitioning catheter having a steerable distal tip for centering the catheter tip within the ascending aorta.
• FIG. 28 illustrates an endoaortic partitioning catheter-including a fiberoptic bundle for transillumination of the aortic wall and/or for facilitating non-fluoroscopic placement of the catheter.
• FIG. 29 illustrates an endoaortic partitioning catheter having an inflatable bumper balloon for protecting the aortic wall from the catheter tip and for facilitating non-fluoroscopic placement of the catheter.
• FIG. 30A is a rear three-quarter view of a frictional locking suture ring for use with the endoaortic partitioning catheter.FIG. 30B is a front three-quarter view of the frictional locking suture ring ofFIG. 30A.
• FIG. 31 is a front view of a dual function arterial cannula and introducer sheath for use with the endoaortic partitioning catheter.
• FIG. 32 is a cross sectional view of the hemostasis fitting of the dual function arterial cannula and introducer sheath ofFIG. 31.
• FIG. 33 illustrates the cannula ofFIG. 31 with an endoaortic partitioning catheter introduced into the catheter insertion chamber.
• FIG. 34 illustrates the cannula ofFIGS. 31 and 32 with the endoaortic partitioning catheter introduced into the patient's femoral artery.
• FIGS. 35A-35C illustrate an endoaortic partitioning catheter having a steerable distal tip with a multichamber balloon for centering the catheter tip within the ascending aorta.
• FIG. 36 illustrates a multifunction embodiment of the endoaortic partitioning catheter combined with a dual function arterial cannula and introducer sheath and a frictional locking suture ring.
• FIG. 37 shows a balloon having a first, high friction portion and a second, low friction portion.
• FIG. 38 is an end view of the balloon ofFIG. 37.
• FIG. 39 is an end view of the balloon ofFIG. 37 in an expanded state.
• FIG. 40 is an isometric view of a second preferred balloon having a first, low friction portion and a second, high friction portion.
• FIG. 41 is an end view of the balloon ofFIG. 40.
• FIG. 42 is a side view of an aorta with clamps positioned on both sides of the occluding member to prevent migration of the occluding member;
• FIG. 43 is a plan view of the clamp ofFIG. 42.
• FIG. 44A is a side view of an aorta with the clamp ofFIG. 42 positioned around the aorta and a balloon trapped by the clamp in the aorta.
• FIG. 44B is a plan view of an intermediate wall positioned in an indentation of the balloon ofFIG. 44A.
• FIG. 45 is a partial cross-sectional view of the delivery cannula ofFIGS. 33 and 34 with a shaft displacing mechanism.
• FIG. 46 is a side view of an aorta with the shaft displaced in an outward direction so that the shaft engages a radially inner wall of the aorta.
• FIG. 47 is a side view of an aorta with a shaft having a two-bend configuration displaced in an inward direction so that the shaft ofFIG. 46 engages a radially outer wall of the aorta.
• FIG. 48 is a side view of an aorta with a shaft having a hook-shaped portion displaced in an outward direction so that the shaft engages a radially inner wall of the aorta.
• FIG. 49 is a side view of an aorta with the shaft ofFIG. 48 displaced in an inward direction so that the shaft engages a radially outer wall of the aorta.
DETAILED DESCRIPTION OF THE INVENTION
• The invention provides a cardiac access system including an endovascular device for partitioning the ascending aorta, as well as a system for selectively arresting the heart, which are useful in performing a variety of cardiovascular, pulmonary, neurosurgical, and other procedures. The procedures with which the invention will find use include repair or replacement of aortic, mitral, and other heart valves, repair of septal defects, pulmonary thrombectomy, electrophysiological mapping and ablation, coronary artery bypass grafting, angioplasty, atherectomy, treatment of aneurysms, myocardial drilling and revascularization, as well as neurovascular and neurosurgical procedures. The invention is especially useful in conjunction with minimally-invasive cardiac procedures, in that it allows the heart to be arrested and the patient to be placed on cardiopulmonary bypass using only endovascular devices, obviating the need for a thoracotomy or other large incision. Moreover, even in conventional open-chest procedures, the endovascular aortic partitioning device of the invention will frequently find use where an external cross-clamp would raise substantial risks of embolus release due to calcification or other aortic conditions.
• Reference is made toFIG. 1 which schematically illustrates the overall cardiac accessing system of the invention and the individual components thereof. The accessing system includes an elongated aortic occlusion orendoaortic partitioning catheter10 which has anexpandable member11 on a distal portion of the catheter which, when inflated as shown, occludes the ascendingaorta12 to separate or partition theleft ventricle13 and upstream portion of the ascending aorta from the rest of the patient's arterial system and securely positions the distal end of the catheter within the ascending aorta. Acardiopulmonary bypass system18 removes venous blood from thefemoral vein16 through theblood withdrawal catheter17 as shown, removes CO₂from the blood, oxygenates the blood, and then returns the oxygenated blood to the patient'sfemoral artery15 through thereturn catheter19 at sufficient pressure so as to flow throughout the patient's arterial system except for the portion blocked by the expanded occludingmember11 on the aortic occludingcatheter10. Theaortic occluding catheter10 has aninfusion lumen40 for antegrade delivery of a fluid containing cardioplegic agents directly into theaortic root12 and subsequently into thecoronary arteries52,53 (shown inFIG. 2) to paralyze the patient's myocardium. Optionally, a retrogradecardioplegia balloon catheter20 may be disposed within the patient's venous system with the distal end of the catheter extending into the coronary sinus21 (shown inFIG. 4) to deliver a fluid containing cardioplegic agents to the myocardium in a retrograde manner through the patient's coronary venous system to paralyze the entire myocardium.
• The elongated occludingcatheter10 extends through the descending aorta to the leftfemoral artery23 and out of the patient through a cut down24. Theproximal extremity25 of thecatheter10 which extends out of the patient is provided with a multi-arm adapter26 with onearm27 adapted to receive aninflation device28. The adapter26 is also provided with asecond arm30 withmain access port31 through which passes instruments, a valve prosthesis, an angioscope, or to direct blood, irrigation fluid, cardioplegic agents and the like to or from the system. Athird arm32 is provided for monitoring aortic root infusion pressure at the distal end of the catheter and/or for directing blood, irrigation fluid, and the like to or from the system. In the system configuration ofFIG. 1, thethird arm32 of the multi-arm adapter26 is connected to acardioplumonary bypass line33 to vent the patient's heart, particularly the left ventricle, and to recover the blood removed and return it to the patient via the cardiopulmonary bypass system. Asuitable valve34 is provided to open and close thebypass line33 and direct the fluid passing through the bypass line to adischarge line35 or aline36 to a blood filter andrecovery unit37. A return line may be provided to return any filtered blood to thecardiopulmonary bypass system18 or other blood conservation system.
• The details of theaortic occlusion catheter10 and the disposition of the distal extremity thereof within the aorta are best illustrated inFIGS. 2 and 3. As indicated, thecatheter10 includes anelongated catheter shaft39 which has a firstinner lumen40 for infusion of a cardioplegic agent in fluid communication with themain access port31 in the second arm of the adapter26. Additionally, theinfusion lumen40 may be adapted to facilitate the passage of instruments, a valve prosthesis, an angioscope, irrigation fluid, and the like therethrough and out thedistal port41 in the distal end thereof. A supportingcoil42 may be provided in the distal portion of the firstinner lumen40 to prevent thecatheter shaft39 from kinking when it straightened for initial introduction into the arterial system or when it is advanced through the aortic arch. Theshaft39 is also provided with a secondinner lumen43 which is in fluid communication with the interior of the occludingballoon11.
• In one embodiment of the system, a retrogradecardioplegia balloon catheter20, which is shown in more detail inFIG. 4, is introduced into the patient's venous system through the right internaljugular vein44 and is advanced through theright atrium45 and into thecoronary sinus21 through the coronary sinus discharge opening46 in the right atrium. Theretrograde catheter20 is provided with aballoon47 on a distal portion of thecatheter20 which is adapted to occlude thecoronary sinus21 when inflated. A liquid containing a cardioplegic agent, e.g. an aqueous KCl solution, is introduced into theproximal end48 of thecatheter20, which extends outside of the patient, under sufficient pressure so that the fluid containing the cardioplegic agent can be forced to pass through thecoronary sinus21, through the capillary beds (not shown) in the patient's myocardium, through thecoronary arteries50 and51 andostia52 and53 associated with the respective coronary arteries into the blocked off portion of the ascendingaorta12 as shown.
• Apulmonary venting catheter54 is also shown inFIG. 4 disposed within the right internaljugular vein44 and extending through theright atrium45 andright ventricle55 into thepulmonary trunk56. Alternatively, thepulmonary venting catheter54 may be introduced through the left jugular. Thecatheter54 passes throughtricuspid valve57 andpulmonary valve58. Aninflatable occluding balloon60 may be provided as shown on a distal portion of thepulmonary venting catheter54 which is inflated to occlude thepulmonary trunk56 as shown. Thepulmonary venting catheter54 has a firstinner lumen61 which extends from the distal end of the catheter to the proximal end of the catheter which vents fluid from thepulmonary trunk56 to outside the patient's body either for discharge or for passage to the blood recovery unit and thereby decompresses theleft atrium14 through the pulmonary capillary beds (not shown). Thecatheter54 has a secondinner lumen62 which is adapted to direct inflation fluid to the interior of theinflatable balloon60.
• To set up the cardiac access system, the patient is initially placed under light general anesthesia. Thewithdrawal catheter17 and thereturn catheter19 of thecardiopulmonary bypass system18 are percutaneously introduced into the rightfemoral vein16 and the rightfemoral artery15, respectively. Anincision24 is also made in the left groin to expose the leftfemoral artery23 and the aortic occludingcatheter10 is inserted into the left femoral artery through an incision therein and advanced upstream until theballoon11 on the distal end of the occludingcatheter10 is properly positioned in the ascendingaorta12. Note that bypass could similarly be established in the left groin and the aortic occlusion catheter put into the right femoral artery. Theretrograde perfusion catheter20 is percutaneously inserted by a suitable means such as the Seldinger technique into the right internaljugular vein44 or the subclavian vein and advanced into theright atrium45 and guided through thedischarge opening46 into the coronary sinus.
• Thepulmonary venting catheter54 is advanced through the right or left internaljugular vein44 or the subclavian vein (whichever is available after introduction of retrograde perfusion catheter20) into theright atrium45,right ventricle55, and into thepulmonary trunk56. The occludingballoon60 may be inflated if necessary by inflation with fluid passing through thelumen62 to block thepulmonary trunk56 and vent blood therein through thelumen61 where it is discharged through the proximal end of the catheter which extends outside of the patient. Alternatively, the occludingballoon60 may be partially inflated with air or CO₂during introduction for flow-assisted placement. The venting of thepulmonary trunk56 results in the decompressing of theleft atrium14 and, in turn, the left ventricle. In the alternative, the ventingcatheter54 may be provided with means on the exterior thereof, such as expanded coils as described in U.S. Pat. No. 4,889,137 (Kolobow), which hold open the tricuspid and pulmonary valves and perform the same function of decompressing the left atrium. See also the article written by F. Rossi et. al. in the Journal of Thoracic Cardiovascular Surgery, 1900; 100: 914-921, entitled “Long-Term Cardiopulmonary Bypass By Peripheral Cannulation In A Model Of Total Heart Failure”, which is incorporated herein in its entirety by reference.
• The operation of thecardiopulmonary bypass unit18 is initiated to withdraw blood from thefemoral vein16 throughcatheter17, remove CO₂from and add oxygen to the withdrawn blood and then pump the oxygenated blood through thereturn catheter19 to the rightfemoral artery15. Theballoon11 may then be inflated to occlude the ascendingaorta12, causing the blood pumped out of the left ventricle (until the heart stops beating due to the cardioplegic fluid as discussed hereinafter) to flow through thedischarge port41 into the firstinner lumen40 of the occluding catheter. The blood flows through theinner lumen40 and out thethird arm32 of the adapter26 into thebypass line33 and then into the blood filter andblood recovery unit37 through thevalve34 andline36. For blood and irrigation fluids containing debris and the like, the position of thevalve34 may be changed to direct the fluid through thedischarge line35.
• In a first embodiment of the method, a liquid containing a cardioplegic agent such as KCl is directed through theinfusion lumen40 of thecatheter10 into theaortic root12 and subsequently into thecoronary arteries52,53 to paralyze the patient's myocardium. Alternatively, if aretroperfusion catheter20 is provided for delivery of the cardioplegic agent, theballoon47 on the distal extremity of thecatheter20 is inflated to occlude thecoronary sinus21 to prevent fluid loss through thedischarge opening46 into theright atrium45. A liquid containing a cardioplegic agent such as KCl is directed through thecatheter20 into thecoronary sinus21 and the pressure of the cardioplegic fluid within thecoronary sinus21 is maintained sufficiently high, (e.g. 40 mm Hg) so that the cardioplegic fluid will pass through the coronary veins, crossing the capillary beds to thecoronary arteries50 and51 and out theostia52 and53. The cardioplegic fluid pressure within thecoronary sinus21 should be maintained below 75 mm Hg to avoid pressure damage to thecoronary sinus21. Once the cardioplegic fluid passes through the capillary beds in the myocardium, the heart very quickly stops beating. At that point the myocardium is paralyzed and has very little demand for oxygen and can be maintained in this state for long periods of time with minimal damage.
• With the cardiopulmonary bypass system in operation, the heart completely paralyzed and not pumping, the left atrium and ventricle decompressed and the ascending aorta blocked by theinflated balloon11 on the occludingcatheter10, the heart is appropriately prepared for a cardiac procedure.
• Inflation of theinflatable member11 on the distal end of thedelivery catheter10 fixes the distal end of the occludingcatheter10 within the ascendingaorta12 and isolates theleft ventricle13 and the upstream portion of the ascending aorta from the rest of the arterial system downstream from the inflatable member. The passage of any debris or emboli, solid or gaseous, generated during a cardiovascular procedure to regions downstream from the site would be precluded by theinflated balloon11. Fluid containing debris or emboli can be removed from the region between the aortic valve and the occludingballoon11 through theinner lumen40 ofcatheter10. A clear, compatible fluid, e.g. an aqueous based fluid such as saline delivered through theinner lumen40 or the cardioplegic fluid discharging from the coronary ostia52 and53, may be maintained in the region wherein the cardiovascular procedure is to be performed to facilitate use of an angioscope or other imaging means that allows for direct observation of the cardiac procedure. Preferably, the fluid pressure in theleft ventricle13 is maintained sufficiently higher than that in the left atrium to prevent blood from the left atrium from seeping into the left ventricle and interfering with the observation of the procedure.
• FIG. 5A shows a longitudinal cross section of a first preferred embodiment of theendoaortic partitioning catheter100 of the present invention. Theendoaortic partitioning catheter100 ofFIG. 5A is made with a coaxial construction, which indicates that thecatheter100 is constructed of a first,inner tube102 within a second,outer tube104. Theinner tube102 and theouter tube104 of thecatheter100 combine to form anelongated shaft106 that runs from aproximal hub108 to the distal end of thecatheter100 having anaortic occlusion balloon110 mounted thereon. The length of theshaft106 is such that thecatheter100 can be introduced into the patient's aorta by way of an arterial cutdown or the Seldinger technique into a peripheral artery, such as the femoral or brachial artery, and advanced into the ascending aorta. For introduction by way of a femoral artery or iliac artery the length of theshaft106 is preferably 80 to 125 cm. For introduction by way of a brachial artery, the carotid artery or through a penetration directly into the aorta, the length of theshaft106 is preferably 20 to 80 cm.
• In the embodiment ofFIG. 5A, theinner tube102 of thecatheter100 is a two lumen tube, having a crescent-shapedcardioplegia infusion lumen112 which wraps around a circulardistal pressure lumen114, as shown in cross section inFIGS. 5B and 5C. Thecardioplegia infusion lumen112 and thedistal pressure lumen114 are open at the distal end of thecatheter100. Thecardioplegia infusion lumen112 preferably has a cross sectional area sufficient for delivering a mixture of warm or cooled, oxygenated blood and cardioplegia solution at a rate of from about 200 ml/min to 400 ml/min with an infusion pressure not to exceed 300 mm Hg. In one presently preferred embodiment, the cross sectional area of thecardioplegia infusion lumen112 is approximately 5.74 mm²(0.00889 in²) for a catheter with a length of about 120-130 cm. The cross sectional area of thecardioplegia infusion lumen112 necessary to deliver the desired flow rate will vary somewhat depending on the length of thecatheter shaft106 and the ratio of blood to cardioplegic solution in the mixture. Thedistal pressure lumen114 preferably has a cross sectional area sufficient to transmit the pressure within the aortic root along the length of thecatheter shaft106 without excessive damping of the pressure wave. In a preferred embodiment having a shaft length of about 120-130 cm, adistal pressure lumen114 having an internal diameter of 0.61 mm, and therefore a cross sectional area of 0.29 mm²(0.00045 in²), provides the desired pressure signal transmission.
• Theouter tube104 of thecatheter100 fits coaxially around theinner tube102 with an annular space between the two tubes providing aballoon inflation lumen116, as shown in cross section inFIG. 3C. The external diameter of thecatheter100 can be made within the range of 8-23 French (Charrière scale), preferably in the range of 8-12 French. In one preferred embodiment of thecatheter100, theouter tube104 has an external diameter of 3.4-3.5 mm or approximately 10.5 French (Charri{fraction (e)}re scale). In a second preferred embodiment of thecatheter100, theouter tube104 has an external diameter of 3.2-3.3 mm or approximately 10 French (Charrière scale). Anaortic occlusion balloon110 is mounted on the distal end of thecatheter100. Theaortic occlusion balloon110 has aproximal balloon neck118 which is sealingly attached to theouter tube104 and adistal balloon neck120 which is sealingly attached to theinner tube102 of thecatheter100 so that theballoon inflation lumen116 communicates with the interior of theballoon110. Preferably, theballoon inflation lumen116 has a cross sectional area of approximately 0.5-1.0 mm²(0.00077-0.00155 in²) to allow rapid inflation and deflation of theaortic occlusion balloon110. In a particular presently preferred embodiment with the described configuration, theballoon inflation lumen116 has a cross sectional area of approximately 0.626 mm²(0.00097 in²) which allows theocclusion balloon110 be inflated to a recommended maximum volume of 40 cc with saline solution or saline solution mixed with a radiopaque contrast agent at an inflation pressure of 35 psi in 40 seconds or less, preferably in 20 seconds or less. Whether inflating by hand or using a mechanical inflation device, the inflation of the balloon is preferably volume-limited so that, although the transient, peak inflation pressure reaches approximately 35 psi, the inflation pressure decreases to about 10-12 psi to maintain balloon inflation when the balloon reaches its desired inflation volume. Theballoon inflation lumen116 also allows theocclusion balloon110 be deflated in 60 seconds or less, preferably in 40 seconds or less. Theocclusion balloon110 can be inflated and deflated by hand using an ordinary syringe or it can be inflated and deflated using an inflation device which provides a mechanical advantage or that is powered by compressed air or an electric motor.
• FIG. 5D is a detail drawing showing the construction ofsection5D-5D of thecatheter100 ofFIG. 5A. Theproximal balloon neck118 is bonded to the distal end of theouter tube104 in a lap joint. The bond between theproximal balloon neck118 and theouter tube104 and the bond between thedistal balloon neck120 and theinner tube102 can be formed by adhesive bonding, by solvent bonding or by heat bonding depending on the materials chosen for each component. Alternatively, theouter tube104 can be formed from a single continuous extrusion with the material of theaortic occlusion balloon110.
• Theproximal hub108 of thecatheter100 has a luer fittingballoon inflation port122 that is sealingly connected to theballoon inflation lumen116, a luer fittingpressure monitoring port124 that is sealingly connected to thedistal pressure lumen114, and aninfusion port126 that is sealingly connected to thecardioplegia infusion lumen112. Theproximal hub108 may be joined to the proximal ends of theinner tube102 and theouter tube104 by adhesive bonding, by insert molding or by other known processes.
• In the embodiment ofFIG. 5A, theaortic occlusion balloon110 is shown as having a generally spherical geometry in theunexpanded state110, as well as a generally spherical geometry in the expanded orinflated state110′. Other possible geometries for the balloon in theunexpanded state110 include cylindrical, oval or football-shaped, eccentric or other shaped balloons. Some of these variations are further described below. In this preferred embodiment theballoon110 is made of an elastomeric material that expands elastically from the uninflated to the inflated state. Preferred materials for theballoon110 include latex, silicone, and polyurethane, chosen for their elasticity, strength and biocompatibility for short term contact with the blood and body tissues.
• FIG. 6A shows a lateral side view of a second preferred embodiment of theendoaortic partitioning catheter200. In this embodiment theinner tube202 has been made with a D-shapedcardioplegia infusion lumen212 and a D-shapeddistal pressure lumen214. The choice of D-shaped lumens in theinner tube202, makes it possible to maximize the diametrical clearance within thecardioplegia infusion lumen212 for a given cross sectional area, as compared to the crescent-shapedcardioplegia infusion lumen112 ofFIG. 5C. This variation of thecatheter200 may be preferable when catheters or other instruments are to be introduced to the heart and its associated blood vessels through thecardioplegia infusion lumen212.
• As shown inFIG. 6A, theocclusion balloon210 of this embodiment has an ellipsoidal or football-shaped deflated profile which is imparted by the balloon molding process. The wall thickness of the moldedballoon210 in its deflated state is typically about 0.090-0.130 mm. Typically, the deflatedballoon210 has a diameter of approximately 12 mm before it is folded, although deflated balloon diameters of 3 to 20 mm are possible. Theinflated balloon210′ assumes a roughly spherical shape with a maximum diameter of approximately 40 mm when inflated. The football shape of the molded balloon has been shown to be advantageous in that the deflatedballoon210 has a deflated profile which is less bulky and smoother than for other balloon geometries tested. This allows the deflatedballoon210 to be folded and more easily inserted through a percutaneous puncture into the femoral artery or through an introducer sheath or a dual function arterial cannula and introducer sheath. In this embodiment as well, theballoon210 is preferably made of an elastomeric material such as latex, silicone, or polyurethane. In one particular embodiment, the football-shaped balloon has an internal geometry determined by a positive dip molding mandrel with a radius of curvature in the central portion of the balloon of approximately 1.0 inch with a maximum diameter in the center of the balloon of about 0.5 inch. The curvature of the central portion of the balloon has a smoothly radiused transition, for example with a radius of about 0.25 inch, to the proximal and distal balloon sleeves, which are sized to fit snugly onto the exterior of the chosen diameter catheter shaft.
• FIG. 7A shows a longitudinal cross section of a third preferred embodiment of theendoaortic partitioning catheter300. Thecatheter300 of this embodiment has a coaxial construction having a single lumeninner tube302 surrounded by a single lumenouter tube304. The single lumeninner tube302 has a circularcardioplegia infusion lumen312 that is connected on its proximal end to the infusion port326 of theproximal hub308 of thecatheter300. Thecardioplegia infusion lumen312 is open at the distal end of thecatheter300. The single lumenouter tube304 of thecatheter300 fits coaxially around theinner tube302 with an annular space between the two tubes providing aballoon inflation lumen316. Theballoon inflation lumen316 is connected on its proximal end to theballoon inflation port322 of theproximal hub308.
• In this embodiment, the aortic root pressure monitoring function is fulfilled by adistal pressure transducer330 mounted at the distal tip332 of thecatheter300. Thedistal pressure transducer330 electronically monitors the aortic root pressure and transmits a signal alongsignal wires334 and336 toelectrical connections338 and340 within anelectrical connector324 on theproximal hub308 of thecatheter300. The electrical connector is adapted to be connected to an electronic pressure monitor which displays an analog or digital indication of the pressure at the distal end332 of thecatheter300. Thedistal pressure transducer330 is preferably a piezoelectric pressure transducer which creates a voltage signal indicative of the external fluid pressure exerted on thetransducer330. Examples of piezoelectric materials suitable for construction of thedistal pressure transducer330 include piezoelectric polymers such as polyvinylidene bifluoride or Kynar™ (Elf Atochem SA), or piezoelectric ceramics such as lead barium titanate, zirconium barium titanate or other commercially available piezoelectric materials. The geometry of thedistal pressure transducer330 may be a ring encircling the distal tip332 of thecatheter300, as shown inFIGS. 7A and 7B. Alternatively, a small patch of the piezoelectric material may be mounted on one side of the distal tip332 of thecatheter300. Thedistal pressure transducer330 preferably has a pressure sensing range from about −75 to 300 mm Hg or greater (−1.5 to 5.7 psi) so as to be able to measure root pressure during cardioplegia infusion and during venting of the aortic root.
• Optionally, a balloonpressure monitoring transducer350 may also be mounted within theballoon310 of thecatheter300 for monitoring the inflation pressure of theballoon310. The balloonpressure monitoring transducer350 electronically monitors the balloon inflation pressure and transmits a signal alongsignal wires352 and354 toelectrical connections356 and358 within theelectrical connector324 on theproximal hub308 of thecatheter300. The balloonpressure monitoring transducer350 is preferably a piezoelectric pressure transducer which creates a voltage signal indicative of the external fluid pressure exerted on thetransducer350, made for example from one the piezoelectric polymers or piezoelectric ceramics designated above in connection with thedistal pressure transducer330. The balloonpressure monitoring transducer350 preferably has a pressure sensing range from about −760 to 300 mm Hg or greater (−15 to 35 psi) so as to be able to measure balloon pressure during inflation and deflation of theocclusion balloon310. The balloonpressure monitoring transducer350 can be used to monitor internal balloon pressure to make sure that theocclusion balloon310 has been inflated to proper pressure to insure reliable occlusion of the ascending aorta. The balloonpressure monitoring transducer350 can also be used to determine when theocclusion balloon310 has contacted the interior wall of the ascending aorta by monitoring for a spike in the inflation pressure within the balloon or for an inflection point in the pressure/volume curve while inflating. A safe inflation volume can be determined for each individual patient by a protocol wherein theocclusion balloon310 is inflated until it contacts the interior wall of the ascending aorta, then a set volume of inflation fluid is added to create a reliable seal to occlude the aortic lumen. Alternatively, the protocol for inflation could include determining when theocclusion balloon310 contacts the aortic wall and incrementally increasing the pressure a set amount to form a seal.
• In a specific embodiment, thepressure transducer350 monitors the pressure in theballoon310 and transmits the pressure information to apressure monitor353 viasignal wires352,354 andelectrical connections356,358. The pressure monitor353 is also coupled to a source ofinflation fluid355 for determining an amount of inflation fluid injected into theballoon310. The pressure monitor353 is configured to determine the rate of pressure increase relative to the fluid volume injected in the balloon351 from thefluid source355. The pressure monitor353 determines when a pressure spike in the pressure vs. fluid volume is detected. The pressure spike generally indicates that theballoon310 has engaged the aortic lumen at which point the pressure increases more rapidly with respect to the fluid volume. The slope of the pressure spike which triggers the pressure monitor353 depends upon a number of factors including the size, shape and elasticity of theballoon310. It is contemplated that the magnitude of the pressure spike may be determined empirically by testing balloons with various size passageways. After the pressure spike is detected, the pressure monitor353 sends a signal to the source ofinflation fluid355 to either add a predetermined amount of fluid or to add fluid until a predetermined increase in pressure is sensed. The predetermined amount of fluid and/or predetermined increase in pressure both add an additional amount of holding force to prevent migration of the balloon while minimizing distention of the aorta.
• In yet another aspect of the invention, the catheter includes aproximal pressure transducer331 which monitors the pressure on a proximal side of the balloon351 and transmits a signal to the pressure monitor353 viawires339,341. Thepressure transducer330 andproximal pressure transducer331 are coupled to the pressure monitor353 which monitors the pressures and, furthermore, determines a pressure differential between thetransducers330,331. The pressure monitor353 preferably includes analarm357, which may be a visual or audible alarm, which tells the user that the pressure differential measured by thetransducers330,331 exceeds a predetermined threshold.
• When the pressure differential exceeds the predetermined threshold, the pressure on one or both sides of the balloon351 is adjusted so that the pressure differential does not exceed the predetermined threshold. When thecatheter300 is used in conjunction with cardiopulmonary bypass as explained above, thecatheter300 delivers cardioplegic fluid through the infusion port from a source ofcardioplegic fluid359. The delivery of cardioplegic fluid from the source ofcardioplegic fluid359 may be adjusted so that the pressure differential does not exceed the predetermined threshold. Alternatively, the pressure on the proximal side of the balloon may be adjusted so that the pressure differential is below the threshold differential pressure. The above described embodiments having thepressure transducers330,350,331 and pressure monitors353 described in conjunction with the embodiment ofFIG. 7A may be used with any other occluding member or balloon and are generally directed to techniques for minimizing migration of occluding members. Furthermore, although the use ofpressure transducers330,350,331 is preferred, any other devices for measuring the balloon and fluid pressures may be used without departing from the scope of the invention.
• Thesignal wires334,336,339,341,352,354 from thepressure transducers330,350,331 extend through theannular inflation lumen316 between theinner tube302 and theouter tube304. Thesignal wires334,336,352,354,339,341 may be laid loosely in theinflation lumen316 with some slack, or they may be spiraled around theinner tube302 so that they do not adversely affect the bending characteristics of thecatheter300. Alternatively, the signal wires may be embedded in the wall of theinner tube302, either during the extrusion process or in a post-extrusion operation. In order to have electrical impedance to match the impedance of thetransducers330,350 and/or theelectronic pressure monitor353, the signal wires may be provided as parallel pairs, twisted pairs or coaxial cables, as required.
• The use of adistal pressure transducer330 for monitoring aortic root pressure eliminates the need for a separate pressure monitoring lumen in the catheter as provided in the embodiments ofFIGS. 5A and 6A. This allows a reduction in the catheter external diameter without sacrificing catheter performance in terms of the cardioplegia flow rate in theinfusion lumen312 and the speed of balloon inflation and deflation through theballoon inflation lumen316. A 10 French (3.3 mm external diameter) catheter constructed according to this design provides a flow rate and balloon inflation performance comparable to a 10.5 French (3.5 mm external diameter) catheter constructed with a separate pressure monitoring lumen. Reducing the external diameter of the catheter in this way has a number of clinical advantages. The smaller diameter catheter will be easier to introduce into a patient's femoral, brachial or other artery by either the Seldinger technique or by an arterial cutdown or by insertion through an introducer sheath. It will also be possible to introduce the smaller diameter catheter into smaller arteries, as encountered in smaller patients, particularly female and pediatric patients. This will increase the clinical applicability of the catheter and the method for its use to a greater patient population. In all patients, the smaller diameter catheter will cause less trauma to the artery it is introduced through, thereby reducing the likelihood of complications, such as bleeding or hematoma at the arterial access site. The smaller diameter catheter will also be particularly advantageous when used in conjunction with the dual function arterial cannula and introducer sheath described below in relation toFIGS. 31-34 because the smaller diameter shaft will occupy less of the blood flow lumen of the cannula, allowing higher blood flow rates at lower pressures. With these improvements, the external diameter of an endoaortic partitioning catheter for use with warm blood cardioplegia can be reduced to 8 to 10 French (2.7-3.3 mm external diameter) and for use with crystalloid cardioplegia can be reduced to 7 to 9 French (2.3-3.0 mm external diameter). Although use of the pressure transducers have been described in connection with the inflatable balloon ofFIG. 7A, the pressure transducers may be used with any other occluding member without departing from the scope of the invention.
• Further improvements in reducing the effective diameter of the catheter during introduction or removal of the catheter from the peripheral arterial access site can be accomplished by making the occlusion balloon self-collapsing around the catheter. Two embodiments of coaxial-construction catheters with self-collapsing occlusion balloons are shown inFIGS. 8A-8C and9A-9B.
• FIG. 8A shows a transverse cross section of a coaxial-constructionendoaortic partitioning catheter400 in which theinner tube402 and theouter tube404 are axially movable with respect to one another. Theinner tube402 has acardioplegia infusion lumen412 and apressure monitoring lumen414. Theinner tube402 is connected to a firstproximal hub430 with luerfitting connections426 and424 in communication with thecardioplegia infusion lumen412 and thepressure monitoring lumen414, respectively. Theouter tube404 fits coaxially around theinner tube402 with an annular space between the two tubes providing aballoon inflation lumen416. Theouter tube404 is connected to a secondproximal hub432 with a luerfitting connection422 for theballoon inflation lumen416. Theinner tube402 passes through the secondproximal hub432 exiting through a slidingfluid seal440 that allows axial movement of theinner tube402 with respect to the secondproximal hub432 and theouter tube404.
• In one preferred embodiment the slidingfluid seal440 is a type of compression fitting known in the industry as a Tuohy-Borst adapter. The Tuohy-Borst adapter440 has a compressible tubular or ring-shapedelastomeric seal442 that fits within abore446 on the proximal end of the secondproximal hub432. A threadedcompression cap444 fits onto the proximal end of the secondproximal hub432. When thecompression cap444 is tightened, it compresses theelastomeric seal442 axially, which causes the lumen448 of theseal442 to narrow and seal against theinner tube402. The Tuohy-Borst adapter440 can also be used to lock the position of theinner tube402 with respect to the secondproximal hub432 and theouter tube404 by tightening thecompression cap444 until the friction between theelastomeric seal442 andinner tube402 effectively locks them together to prevent axial movement between the two.
• In a second preferred embodiment, shown inFIG. 8D, a slidingfluid seal440 is combined with alocking mechanism450 to lock theinner tube402 with respect to theouter tube404 to prevent axial movement between the two. Thelocking mechanism450 may comprise a threadedshaft452 in alignment with theinner tube402 and alock nut454 threaded onto theshaft452. By turning thelock nut454 on the threadedshaft452, the user can adjust the position of theinner tube402 relative to theouter tube404 to increase or decrease the length of theocclusion balloon410 when inflated. The slidingfluid seal440 may be a Tuohy-Borst adapter as described above or, because aseparate locking mechanism450 is provided, it may be a simple sliding seal, such as an O-ring orwiper seal456, as illustrated.
• When theballoon410 is deflated theinner tube402 can be moved to its furthest distal position and locked with respect to theouter tube404, as shown inFIG. 6A. This stretches the wall of theocclusion balloon410 collapsing the deflated balloon tightly around theinner tube402 to reduce the deflated profile for easy introduction through the peripheral arterial access site or through an introducer sheath. Once theocclusion balloon410 has been advanced to the desired location in the ascending aorta, thelocking mechanism440 can be released so that theballoon410 can be inflated.FIG. 6B shows theendoaortic partitioning catheter400 ofFIG. 1A with theinner tube402 in an intermediate position with respect to theouter tube404 and theocclusion balloon410′ inflated. In this position, theinner tube402 and theouter tube404 keeps a tension on the ends of theocclusion balloon410′ which elongates the balloon somewhat in the axial direction. This results in theballoon410′ having a somewhat oblong inflated profile which is smaller in diameter and longer axially than the typical spherical shape of a freely inflated balloon.FIG. 6C shows theendoaortic partitioning catheter400 ofFIGS. 1A and 1B with theinner tube402 in its farther proximal position with respect to theouter tube404 and theocclusion balloon410″ inflated. In this position, theinner tube402 and theouter tube404 places a compressive force on the ends of theocclusion balloon410″ which restricts the expansion of the balloon somewhat in the axial direction. This results in theballoon410″ having an inflated profile which achieves the full diameter of a freely inflated balloon diameter, but is somewhat shorter in the axial direction. This feature allows the user to select the inflated diameter of the balloon and the axial length of the balloon, and therefore the length of contact with the aortic wall, within certain ranges, as well as allowing the balloon to be more fully collapsed when deflated for insertion and removal. The range of useful balloon diameters of theocclusion balloon410 for use in an adult human ascending aorta is from above 20 to 40 cm. Other ranges of balloon diameters may be needed for pediatric patients or nonhuman subjects.
• This feature will find particular utility when theendoaortic partitioning catheter400 is used while performing surgery or other interventional procedures on the aortic valve, or within the aortic root or ascending aorta. To facilitate the surgery, it will be important to provide as much clearance as possible between theinflated occlusion balloon410″ and the aortic valve to allow manipulation of instruments within the ascending aorta while at the same time being sure that theocclusion balloon410″ does not occlude the brachiocephalic artery. In this case, theinner tube402 would be adjusted to its farthest proximal position with respect to theouter tube404 before theocclusion balloon410″ is inflated in order to restrict the size of theballoon410″ as much as possible in the axial direction.
• FIG. 9A shows a transverse cross section of a coaxial-constructionendoaortic partitioning catheter500 in which theinner tube502 and theouter tube504 are rotatable with respect to one another. Theinner tube502 has acardioplegia infusion lumen512 connected to a luerfitting connection526 on theproximal hub508. Theouter tube504 fits coaxially around theinner tube502 with an annular space between the two tubes providing aballoon inflation lumen516 which communicates with a luerfitting connection522 on theproximal hub508. Theouter tube504 is connected to arotating collar540 which is rotatably and slidably mounted on the distal end of theproximal hub508. There is an O-ring seal542 or other type of fluid tight seal between therotating collar540 and theproximal hub508. Anaortic occlusion balloon510 is mounted on the distal end of thecatheter500 with theproximal balloon neck518 sealingly attached to theouter tube504 and thedistal balloon neck520 sealingly attached to theinner tube502 of thecatheter500 so that theballoon inflation lumen516 communicates with the interior of theballoon510. Theocclusion balloon510 is preferably made of an elastomeric material, such as latex, silicone or polyurethane. A piezoelectricdistal pressure transducer530 mounted at the distal tip of thecatheter500 electronically monitors the aortic root pressure and transmits a signal alongsignal wires532 and534 toelectrical connections536 and538 within anelectrical connector524 on theproximal hub508 of thecatheter500.
• In order to collapse theocclusion balloon510 to its lowest possible deflated profile for introduction or withdrawal of thecatheter500 through a peripheral arterial access site or through an introducer sheath, therotating collar540 can be rotated with respect to theproximal hub508 to twist the deflatedocclusion balloon510 around theinner tube502. In addition, therotating collar540 can also be moved proximally with respect to theproximal hub508 to tension the balloon to create an even lower deflated profile. After the catheter has been introduced and maneuvered to the desired position, therotating collar540 is counter rotated to release the balloon from its twisted state before inflation. Thecatheter500 with the fully inflatedocclusion balloon510′ is shown inFIG. 9B. When the catheter is to be withdrawn after use, theocclusion balloon510 is deflated and therotating collar540 is again rotated and moved proximally with respect to theproximal hub508 to twist the deflatedocclusion balloon510 around theinner tube502 to create a lower deflated profile for removal of thecatheter500.
• In each of the previously described embodiments, the shaft of the catheter, whether it has a coaxial construction or a multilumen construction, may take one of a variety of forms. In the simplest form, the shaft of the catheter may be a straight length of flexible tubing, made from a highly flexible plastic or elastomer, such as polyurethane, polyethylene, polyvinylchloride or a polyamide polyether block copolymer, preferably in the range of 35 to 72 Shore D durometer. Another variation of this embodiment would be to provide a straight shaft with zones of varying stiffness graduated from a stiff proximal section to a highly flexible distal section. The variable stiffness shaft could be made by welding tubing segments of different stiffness polymers end-to-end to create two, three or more zones of stiffness. In one illustrative embodiment, the catheter shaft could be made with a stiff proximal section of a polyamide polyether block copolymer with a hardness of 63 to 72 Shore D durometer, an intermediate section of a softer grade of the same polymer with a hardness of 55 to 63 Shore D durometer, and a distal section of a very soft grade of the polymer with a hardness of 35 to 55 Shore D durometer. In addition, an especially flexible soft tip with a hardness of 25 to 35 Shore D durometer may be molded or heat bonded to the distal end of the catheter shaft. Alternatively, the shaft can be made with continuously graduated stiffness from the proximal to distal end using a process such as total intermittent extrusion to gradually change the stiffness along the length of the catheter shaft. In a coaxial-construction catheter either or both of the inner tube and the outer tube may be made with varying stiffness to achieve the overall effect of a graduated stiffness catheter. Furthermore, either or both of the inner tube and the outer tube may be reinforced with wire or filament braiding or coils for increased stiffness, torque control or kink resistance.
• The polymeric material of the shaft is preferably loaded with a radiopaque filler, such as bismuth subcarbonate, bismuth oxychloride, bismuth trioxide, barium sulfate or another radiopaque material. The shaft is preferably loaded with a level of between about 10 and 30 percent of radiopaque filler by weight, preferably about 20%. The soft tip may be loaded with a higher percent of radiopaque filler, such as about 30 to 35 percent by weight for greater fluoroscopic visibility. Instead of or in addition to the radiopaque filler, radiopaque markers, for example rings of gold, platinum, tin, tantalum or tungsten alloys may be attached to the catheter shaft at various points along the length, especially at the tip of the catheter for fluoroscopic visibility.
• In such an embodiment, the highly flexible catheter would be advanced through the patient's descending aorta and into the ascending aorta with a stiffer guidewire and/and or a dilator placed in the infusion lumen of the catheter to provide stiffness for advancing and maneuvering the catheter into position. With the varying stiffness embodiment, the stiffness of the proximal shaft segment will assist in advancing and maneuvering the catheter into position. If desired, a curved guidewire or dilator may be used to assist in forming the catheter shaft to the curve of the aortic arch. Once the catheter is in position, the balloon would be inflated to occlude the ascending aorta and the guidewire or dilator withdrawn to free the infusion lumen for infusing cardioplegic fluid.
• In another approach, the catheter shaft may be made of a somewhat stiffer polymer so that the distal segment of the catheter can be precurved to a configuration that assists in maneuvering the occlusion balloon into the correct position within the ascending aorta. As with the straight catheter shaft previously described, the precurved catheter shaft may also be made with varying degrees of stiffness graduated from a stiff proximal segment to a flexible distal segment. The shaft would be made of slightly higher durometer grades of a flexible plastic or elastomer, such as polyurethane, polyethylene, polyvinylchloride or a polyamide polyether block copolymer, preferably in the range of 55 to 72 Shore D durormeter. A short, very flexible tip of a low durometer polymer, preferably in the range of 25 to 35 Shore D durometer, can be added to the distal end to make it less traumatic to the arterial walls and the aortic valve which it may come in contact with. Two variations of precurved catheter shafts are shown inFIGS. 10A-10C and11A-11C. For the purposes of illustration, these embodiments are shown as built in a multilumen construction, but the precurved shafts can as well be made in one of the coaxial constructions previously described.
• One preferred embodiment of anaortic partitioning catheter600 with a precurved shaft is shown inFIG. 10A. In this embodiment thedistal portion604 of thecatheter shaft602 is configured to facilitate placement of theocclusion balloon610 into the ascending aorta. The curve of thecatheter shaft602 also stabilizes the catheter in the proper position to prevent migration or dislodgement of the inflated occlusion balloon. Thedistal portion604 of thecatheter shaft602 has a curve of approximately 270-300 degrees of arc. The curve of thecatheter shaft602 is a compound curve having afirst segment606 of approximately 135° of arc with a radius of curvature of approximately 75-95 mm. Contiguous with the first segment is asecond segment608 of approximately 135° of arc with a tighter radius of curvature of approximately 40-50 mm. Continuing from the second segment is athird segment612 of approximately 25-50 mm in length adjacent to thedistal end614 of the catheter. Theocclusion balloon610 is mounted on thethird segment612 of the catheter shaft near thedistal end614 of thecatheter600. Thethird segment612 of thecatheter600 may be straight, so that the total arc subtended by thecatheter curve604 is approximately 270°. Alternatively, thethird segment612 of thecatheter600 may be angled upward at a point about midway along thethird segment612, as shown inFIG. 10A, creating a total arc of curvature of about 300°. The upward angle of thethird segment612 helps thecatheter600 to follow a dilator or guidewire as it passes over the curve of the aortic arch during catheter introduction. The angle of thethird segment612 also helps to prevent thedistal tip614 of thecatheter600 from contacting the interior wall of the aorta as it passes over the aortic arch thereby reducing the likelihood of irritating or damaging the aortic wall or of dislodging calculi or other sources of potential emboli. The curve of the catheter is generally coplanar, as shown in the side view inFIG. 10B. The specifics of this catheter curve are given as an illustrative example of one preferred embodiment. The precise angles and lengths of the curve may be varied according to the geometry of the patient's anatomy based on fluoroscopic observation of the aortic arch.
• A cross section of the catheter shaft is shown inFIG. 10C. Thecatheter shaft602 is made from a multilumen extrusion of a flexible plastic or elastomer, such as polyurethane, polyethylene, polyvinylchloride or a polyamide polyether block copolymer, preferably in the range of 55 to 72 Shore D durometer. In one preferred embodiment, themultilumen catheter shaft602 has acardioplegia infusion lumen616, a distalpressure monitoring lumen618, and aballoon inflation lumen620. Theballoon inflation lumen620 is in fluid communication with the interior of theinflatable occlusion balloon610. Theinfusion lumen616 and the distalpressure monitoring lumen618 each connect with separate ports at or near thedistal tip614 of thecatheter600, distal to theocclusion balloon610. For use with blood/cardioplegia techniques, thecatheter shaft602 preferably has an external diameter of 3.5 to 4 mm or 10.5 to 12 French (Charrière scale). For use with crystaloid cardioplegia techniques, thecatheter shaft602 may be made smaller, with an external diameter of 3.3 mm or 10 French (Charri{fraction (e)}re scale) or smaller.
• FIG. 11 is a schematic partly cut-away representation of a patient's aortic arch A with theendoaortic partitioning catheter600 ofFIG. 10A positioned in the ascending aorta B. In use, thedistal curve604 in thecatheter shaft602 ofFIG. 10A is initially straightened out by inserting a guidewire and a dilator (not shown) into theinfusion lumen616 of thecatheter600 to facilitate insertion of thecatheter600 into a peripheral arterial access site such as the femoral artery. Thecatheter600 is advanced until thedistal end614 of thecatheter600 is at the apex of the aortic arch A. Then, the dilator is withdrawn as thecatheter600 is advanced over the aortic arch A to allow the curveddistal portion604 of thecatheter600 to resume its curve within the ascending aorta B. When thecatheter600 is in proper position in the ascending aorta B, thesecond segment608 of the curved shaft conforms to the aortic arch A to hold thedistal tip614 of the catheter centered just above the aortic root R. The firstcurved segment606 of the catheter shaft resides in the descending aorta D, somewhat straightened by its contact with the aortic walls. If the patient has a relatively straight ascending aorta B, as observed fluoroscopically, a straightthird segment612 of the curved shaft is preferred for proper centering of thecatheter tip614 when theocclusion balloon610′ is inflated. If the ascending aorta B is curved, a curved or angleddistal segment612, such as the one illustrated inFIG. 10A, is preferred.
• Another preferred embodiment of anaortic partitioning catheter650 with a precurved shaft is shown inFIG. 12A. In this embodiment also thedistal portion654 of thecatheter shaft652 is configured to facilitate placement of theocclusion balloon660 into the ascending aorta and to stabilize the catheter in the proper position to prevent migration or dislodgement of theinflated occlusion balloon660′, but with a slightly different geometry to accommodate variations in the patient's anatomy. Thedistal portion654 of thecatheter shaft652 has an approximately elliptical curve which subtends approximately 270-300 degrees of arc. Theminor axis646 of the ellipse is parallel to theshaft652 of the catheter and has a length of about 50 to 65 mm. Themajor axis648 of the ellipse is perpendicular to theshaft652 of the catheter and has a length of about 55 to 70 mm. The elliptical curve can also be viewed as having afirst segment656 with a larger radius of curvatures asecond segment658 with smaller radius of curvature and athird segment662 on which theocclusion balloon660 is mounted. The curveddistal portion654 of thecatheter650 is somewhat out of plane with the catheter shaft, angling or spiraling anteriorly from the plane of the catheter shaft by about 10-20°, as shown inFIG. 12B. In one presently preferred embodiment, thedistal tip664 of thecatheter650 has an offset672 from the plane of thecatheter shaft652 of approximately 14 mm. The offset672 of the spiral curve helps to center thecatheter tip664 within the ascending aorta in patients in whom the ascending aorta is angled anteriorly. The preferred degree of offset672 can vary significantly depending on patient anatomy, with an anticipated range of from 0 to 25 mm of offset672 to accommodate most patients. Again, this catheter curve is given as an example of one preferred embodiment. The precise angles and lengths of the curve should be chosen according to the geometry of the patient's anatomy based on fluoroscopic observation of the aortic arch. Providing the catheters in a family of curves which are variations of the curves shown inFIGS. 10A and 12A, etc. will allow the user to select the proper catheter curve for the patient after observing the geometry of the aorta fluoroscopically.
• A cross section of the catheter shaft is shown inFIG. 12C. Thecatheter shaft652 is made from a multilumen extrusion of a flexible plastic or elastomer, such as polyurethane, polyethylene, polyvinylchloride or a polyamide polyether block copolymer, preferably in the range of 55 to 72 Shore D durometer. In this illustrative embodiment, themultilumen catheter shaft652 has acardioplegia infusion lumen666, a distalpressure monitoring lumen668, and aballoon inflation lumen670. Theballoon inflation lumen670 is in fluid communication with the interior of theinflatable occlusion balloon660. Theinfusion lumen666 and the distalpressure monitoring lumen668 each connect with separate ports at or near the distal tip of thecatheter664, distal to theocclusion balloon660. Thecatheter shaft652 can be made in a range of sizes, for instance with an external diameter of 3.5 to 4 mm or 10.5 to 12 French (Charrière scale) for use with blood/cardioplegia techniques, or with an external diameter of 3.3 mm or 10 French (Charrière scale) or smaller for use with crystaloid cardioplegia techniques.
• FIG. 13 is a schematic partly cut away representation of a patient's aortic arch A with theendoaortic partitioning catheter650 ofFIG. 12A positioned in the ascending aorta B. In use, a guidewire and a dilator (not shown) are inserted into theinfusion lumen666 to straighten out thedistal curve654 of thecatheter650. Thecatheter650 is introduced into a peripheral arterial access site such as the femoral artery and advanced until thedistal end664 of thecatheter650 is at the apex of the aortic arch A. Then, the dilator is withdrawn as the catheter is advanced over the aortic arch A to allow thedistal portion652 of thecatheter650 to resume its curve within the ascending aorta B. When thecatheter650 is in proper position in the ascending aorta B, thesecond segment658 of the curved shaft conforms to the aortic arch A to hold thedistal tip664 of the catheter centered just above the aortic root R. Due to its curvature, thesecond segment658 of the catheter shaft tends to hug the inside curve of the aortic arch A which helps to prevent the catheter shaft from occluding or interfering with blood flow into the brachiocephalic artery or other arteries which have their takeoff from the aortic arch. The firstcurved segment656 of thecatheter shaft652 resides in the descending aorta D, somewhat straightened by its contact with the aortic walls. The angled or spiral curve of thecatheter shaft652 assists in centering thedistal tip664 of thecatheter650 within the lumen of the ascending aorta B which is often angled anteriorly within the patient.
• In order to reduce the external diameter of the catheter shaft in the embodiments ofFIGS. 10A-10C and12A-12C, particularly for use in conjunction with the dual purpose arterial cannula and introducer sheath described below in reference toFIGS. 31-34, while maintaining the maximum flow rate performance in the catheter, it is desirable to reduce the wall thickness of the multilumen extrusion as much as possible. In order to improve the kink resistance of the thin-walled catheter shaft in the precurved distal portion (604 inFIG. 10A, 654 inFIG. 12A) it has been found to be advantageous to dip coat the precurved distal portion with a soft, flexible polymer. For example a coating approximately 0.005-0.020 inches thick of a polyurethane with a hardness of 80 Shore A durometer on the precurved distal portion of the catheter shaft has been shown to significantly improve the kink resistance of the catheter shaft. If the coating is applied before mounting the polyurethane occlusion balloon on the catheter shaft, the coating also improves the heat bondability of the occlusion balloon to the shaft. Coating only the distal portion of the catheter shaft has the advantage that it does not increase the external diameter of the catheter shaft in the proximal portion which will reside within the blood flow lumen of the dual purpose arterial cannula and introducer sheath during perfusion. Since the proximal portion of the catheter shaft is not precurved and because it resides in the relatively straight descending aorta during use, it is not necessary to fortify the kink resistance of the shaft in this region.
• One important function of the catheter curves shown inFIGS. 10A and 12A is for centering the tip of the catheter within the ascending aorta before and after the occlusion balloon is inflated to insure even distribution of the cardioplegic fluid to the coronary arteries when it is injected through the infusion lumen into the aortic root. In many cases, the compound curve of the catheter is needed to maintain the catheter tip within the center of the aortic lumen. It has been found that in some cases a simple 180° U-shaped curve results in off-center placement of the catheter tip despite the concentricity of the inflated balloon because of the curve of the ascending aorta. Another approach to centering the distal tip of the catheter within the lumen of the ascending is illustrated by the embodiment of theaortic partitioning catheter700 shown inFIG. 14.
• FIG. 14 is a front view of an embodiment of theendoaortic partitioning catheter700 having an eccentricaortic occlusion balloon710. The occlusion balloon has a symmetrical deflated profile, shown bysolid lines710. The asymmetrical inflated profile, shown byphantom lines710′, is achieved by molding the occlusion balloon with a thicker wall712 on one side of theballoon710. The thicker wall712 of the balloon is oriented toward the inside of thedistal curve704 when mounted on thecatheter shaft702. When theocclusion balloon710′ is inflated, the thicker wall712 resists expansion while thethinner wall714 of the balloon more easily expands to its full potential, resulting in the intended eccentricinflated balloon profile710′. One preferred method for manufacturing theocclusion balloon710 ofFIG. 14 is by a two-stage dip molding process. In the first stage of the process, a balloon mold, in the form of a dipping mandrel having the desired interior shape of the balloon, is oriented vertically and dipped into a solution or a suspension containing an elastomeric balloon material, such as polyurethane, silicone or latex. This creates a relatively even coating of the balloon material over the surface of the mandrel. Thisfirst coating706 is then allowed to dry on the mandrel. Once thefirst coating706 is dry, the orientation of the dipping mandrel is rotated to a horizontal position and one side of the balloon mandrel is dipped into the elastomer solution to create asecond coating708 of balloon material on one side of theballoon710. The balloon mandrel is held in the horizontal orientation until the solvent evaporates from the elastomer solution. If the elastomer used to mold theballoon710 is a thermoplastic elastomer, such as a thermoplastic polyurethane, the balloon can be removed from the dipping mandrel once it has dried. If the elastomer is a thermoset material, such as latex, silicone, or a thermoset polyurethane, further curing of the material may be required before theballoon710 can be removed from the dipping mandrel. It should be noted that thesecond coating708 on theballoon710 may be made of a different material from thefirst coating706. For instance, a stronger or less distensible material may be used for thesecond coating708 to increase the resistance of the thicker wall712 of theballoon710 to inflation. It should also be noted that molding each coating of the balloon may require multiple iterations of the dipping and drying steps, depending on the composition and concentration of the polymer solution. For example, the currently preferred process for manufacturing polyurethane balloons typically requires about 6-8 iterations of the dipping and drying steps to make a finished balloon with a wall thickness of approximately 0.005-0.020 inches.
• FIGS. 15 and 16 illustrate how an eccentric balloon, like theeccentric occlusion balloon710 of the catheter embodiment ofFIG. 14, operates to center the tip of the aortic partitioning catheter within the ascending aorta of a patient.FIG. 15 is a schematic partly cut-away representation of a patient's aortic arch A with anendoaortic partitioning catheter720 having aconcentric occlusion balloon722 positioned in the ascending aorta B. Theendoaortic partitioning catheter720 has a 180°U-shaped catheter curve724 with aconcentric occlusion balloon722 mounted on a straightdistal portion726 of thecatheter720.FIG. 15 shows the effect of placing the U-shaped catheter curve into a patient having a curved ascending aorta B. Note how, when thecatheter720 is pulled proximally to stabilize the catheter within the aortic arch A, thedistal end728 of the catheter is not centered in the aortic lumen despite the concentricity of theballoon722 because of the mismatch between the catheter curve and the curve of the ascending aorta B.
• FIG. 16 is a schematic partly cut-away representation of a patient's aortic arch A with anendoaortic partitioning catheter730 having aneccentric occlusion balloon732 positioned in the ascending aorta B. Theaortic partitioning catheter730 has a U-shapeddistal curve734 which subtends an arc of approximately 180°+/−45°. Mounted on a straightdistal portion736 of the catheter shaft is anocclusion balloon732 which, when inflated, has an eccentric balloon profile with thelarger portion740 of the balloon facing the outside of thecatheter curve734 so that it will be oriented toward the right side of the patient. The eccentric inflated profile of theballoon732 assists in centering thedistal tip738 of thecatheter730 within the aortic lumen when the ascending aorta B is curved. Note how theeccentric balloon732 compensates for the mismatch between the catheter curve and the curve of the ascending aorta B to result in thedistal tip738 of thecatheter730 being well centered in the aortic lumen just above the aortic root R.
• FIG. 17 shows an alternative construction for anocclusion balloon742 with an eccentricinflated profile742′. In this embodiment, theelastomeric balloon742 is molded on a dipping mandrel which is machined with an asymmetrical profile. In contrast to the previous example, the moldedballoon742 has a uniform wall thickness, but it has an asymmetrical deflated profile with alarger side744 and asmaller side746. Theballoon742 is mounted on the catheter with thelarger side744 oriented toward the outside of thedistal curve748 of thecatheter750. When inflated, thelarger side744 of the balloon expands to agreater radius744′ than thesmaller side746′, giving the intended eccentric inflated profile, as shown byphantom lines742′.
• FIGS. 18A and 18B show another alternative construction for anocclusion balloon752 with an eccentricinflated profile752′. In this embodiment, theelastomeric occlusion balloon752 is mounted on thecatheter760 in such a way that theside754 of the balloon oriented toward the inside of thedistal curve758 of the catheter is bonded directly to thecatheter shaft756 along the length of theballoon752 using a suitable adhesive. When theocclusion balloon752 is inflated, only the side of the balloon oriented toward the outside of thedistal curve758 of the catheter shaft is allowed to expand, creating an eccentric inflated balloon profile, as shown byphantom lines752′.
• FIGS. 19A-19D and20A-20D show alternative constructions of an eccentric occlusion balloon made of a nondistensible balloon material, such as polyethylene, polyethylene terephthalate polyester, polyester copolymers, polyamide or polyamide copolymers. Using a nondistensible balloon material such as these allows more precise control over the final shape and dimensions of the inflated occlusion balloon, as compared to the elastomeric balloons previously described. The nondistensible balloons can be thermoformed from tubing extruded from a nonelastomeric polymer, using known methods. Alternatively, the balloons can be dipped or rotomolded of a nonelastomeric polymer in solution. It is presently preferred to mold the inelastic balloon material using a hollow or negative mold of the exterior inflated balloon shape rather than a positive mold of the interior shape as used for the elastomeric balloons, because the molded inelastic balloons may be difficult to remove from a positive mold.
• FIGS. 19A-19D show a first example of a nondistensibleeccentric occlusion balloon762.FIG. 19A shows a side view of the occlusion balloon in the deflatedstate762 andinflated state762′.FIG. 19B shows an end view of the same occlusion balloon in the deflated762 andinflated states762′. Theocclusion balloon762 is molded in an asymmetrical shape with alarge side764 and asmaller side766. Theocclusion balloon762 is mounted on thecatheter shaft768 with thelarger side764 oriented toward the outside of the distal curve of the catheter. The occlusion balloon tends to flatten out, as shown bysolid lines762, when it is deflated. In order to reduce the deflated profile of the balloon for introduction into a peripheral artery, the flattenedballoon762″ is wrapped around thecatheter shaft768 as shown in a side view inFIG. 19C and an end view inFIG. 19D.
• FIGS. 20A-20D show a second example of a nondistensibleeccentric occlusion balloon780.FIG. 20A shows a side view of the occlusion balloon in the deflatedstate780 andinflated state780′.FIG. 20B shows an end view of the same occlusion balloon in the deflatedstate780 andinflated state780′. Theocclusion balloon780 is molded in an asymmetrical shape with alarge side782 and asmaller side784. Theocclusion balloon780 is mounted on thecatheter shaft786 with thelarger side782 oriented toward the outside of the distal curve of the catheter. In this embodiment, thesmaller side784 of the occlusion balloon is adhesively bonded to thecatheter shaft786 along the length of theballoon780 so that theinflated balloon780′ expands only toward the outside of the distal curve of the catheter. The occlusion balloon flattens out, as shown bysolid lines780, when it is deflated. In order to reduce the deflated profile of the balloon for introduction into an artery, the flattenedballoon780″ is wrapped around the catheter shaft as shown in a side view inFIG. 20C and an end view inFIG. 20D.
• The eccentrically shaped occlusion balloons ofFIGS. 14 and 16-20 serve to help center the distal tip of the aortic partitioning catheter within the ascending aorta for uniform distribution of cardioplegic fluid injected through the infusion lumen and for aligning the tip of the catheter with the center of the aortic valve when other instruments are introduced through the infusion lumen. The degree of concentricity of the occlusion balloon can be varied from perfectly concentric to completely eccentric, or one-sided, using the embodiments and methods described in connection withFIGS. 14 and 16-20. Specially shaped occlusion balloons can also be used with the aortic partitioning catheter of the present invention for maximizing the working space within the ascending aorta between the aortic valve and the occlusion balloon. This aspect of the invention will be of particular significance when the catheter system is used for arresting the heart so that surgery or other interventional procedures can be performed on the patient's aortic valve. Whether the aortic valve surgery is performed by thoracoscopic methods, endovascular methods or open chest surgical methods, it will be beneficial to be able to occlude the ascending aorta as required for establishing cardiopulmonary bypass without obstructing surgical access to the aortic valve. This aspect of the invention will also find particular utility when performing port-access CABG surgery with a saphenous vein bypass graft or other free graft which must be anastomosed to the ascending aorta because the occlusion balloon will not interfere with the anastomosis procedure.FIGS. 21-24 show four variations of specially shaped balloons developed for this purpose. These balloons can be manufactured from elastomeric materials or from nondistensible, inelastic materials as previously described.
• FIG. 21 is a schematic partly cut-away representation of a patient's aortic arch A with a first variation of anendoaortic partitioning catheter790 having a shapedocclusion balloon792 positioned in the ascending aorta B. Theocclusion balloon792 has a generally cylindrical outer geometry that has been modified by curving it to match the curvature of the aortic arch A. Thus, the surface of the occlusion balloon facing the outside curve of the aortic arch A has aconvex curvature794 to match the concave curvature of the aortic wall at that point and the surface of the occlusion balloon facing the inside curve of the aortic arch A has aconcave curvature796 to match the convex curvature of the opposite aortic wall. The geometry of theocclusion balloon792 is further modified by molding a groove orindentation798 into the proximal edge of the convexly curvedouter surface794 of theballoon792. Theindentation798 is positioned to allow blood flow past theocclusion balloon792 into the brachiocephalic artery C. This allows theocclusion balloon792 of theaortic partitioning catheter790 to be placed as far downstream in the ascending aorta as possible without occluding flow to the brachiocephalic artery C from the cardiopulmonary bypass system. The working space between the aortic valve V and theocclusion balloon792 is maximized to allow maneuvering of surgical instruments, interventional catheters or a valve prosthesis within the ascending aorta B. Although it does not serve to occlude the aortic lumen, the proximal portion of theocclusion balloon792 contacts the aortic wall and helps to stabilize the inflated balloon within the aorta to keep the distal end of the catheter centered and to help prevent unintended displacement of the inflated balloon.
• FIG. 22 is a schematic partly cut-away representation of a patient's aortic arch A with a second variation of anendoaortic partitioning catheter800 having a shapedocclusion balloon802 positioned in the ascending aorta B. As in the previous example, theocclusion balloon802 has a generally cylindrical outer geometry that has been modified by curving it to match the curvature of the aortic arch A. The surface of the occlusion balloon facing the outside curve of the aortic arch A has aconvex curvature804 to match the concave outer curvature of the aortic wall and the surface of the occlusion balloon facing the inside curve of the aortic arch A has aconcave curvature806 to match the convex inner curvature of the opposite aortic wall. The geometry of theocclusion balloon802 is further modified by molding a large ramp-shapedindentation808 into the proximal side of the convexly curvedouter surface804 of theballoon802. The wall of theocclusion balloon802 can be adhesively attached to thecatheter shaft810 along the length of the ramp-shapedindentation808 to help maintain the geometry of the balloon when subjected to inflation pressure. The ramp-shapedindentation808 is positioned to allow blood flow past theocclusion balloon802 into the brachiocephalic artery C. This allows theocclusion balloon802 of theaortic partitioning catheter800 to be placed as far downstream in the ascending aorta as possible without occluding flow to the brachiocephalic artery C in order to maximize the working space between the aortic valve V and theocclusion balloon802. The broad ramp-shapedindentation808 in theocclusion balloon802 lessens the need for careful placement of theocclusion balloon802 with respect to the brachiocephalic artery C without danger of occluding it. The concavely curvedinner surface806 of theocclusion balloon802 provides an extended contact surface with the wall of the aortic arch A to stabilize theinflated occlusion balloon802 and to discourage unintended movement or dislodgement of theocclusion balloon802. As in the previous embodiment, the proximal portion of theocclusion balloon802 contacts the aortic wall and helps to stabilize the inflated balloon within the aorta to keep the distal end of the catheter centered and to help prevent unintended displacement of the inflated balloon.
• FIG. 23A is a schematic partly cut-away representation of a patient's aortic arch A with a third variation of anendoaortic partitioning catheter820 having a shapedocclusion balloon812 positioned in the ascending aorta B.FIG. 23B is a transverse cross section of the shaped occlusion balloon ofFIG. 23A. Thisocclusion balloon812 also has a generally cylindrical outer geometry that has been modified by curving it to match the curvature of the aortic arch A. The surface of the occlusion balloon facing the outside curve of the aortic arch A has aconvex curvature814 to match the concave outer curvature of the aortic wall and the surface of the occlusion balloon facing the inside curve of the aortic arch A has aconcave curvature816 to match the convex inner curvature of the opposite aortic wall. The geometry of theocclusion balloon812 is further modified by molding an extended groove orinvagination818 into the proximal side of the convexly curvedouter surface814 of theballoon812. Theextended groove818 should have a width at least as wide as the ostium of the brachiocephalic artery C. The wall of theocclusion balloon812 can be adhesively attached to thecatheter shaft822 along the length of theextended groove818 to help maintain the geometry of the balloon when subjected to inflation pressure. Theextended groove818 is positioned to allow blood flow past theocclusion balloon812 into the brachiocephalic artery C. This allows theocclusion balloon812 of theaortic partitioning catheter800 to be placed even farther downstream in the ascending aorta without occluding flow to the brachiocephalic artery C in order to maximize the working space between the aortic valve V and theocclusion balloon812. Again, the concavely curvedinner surface816 of theocclusion balloon812 provides an extended contact surface with the wall of the aortic arch A to stabilize theinflated occlusion balloon812 and to discourage unintended movement or dislodgement of theocclusion balloon812.
• FIG. 24 is a schematic partly cut-away representation of a patient's aortic arch A with a fourth variation of anendoaortic partitioning catheter824 having a shapedocclusion balloon826 positioned at the apex of the aortic arch A. In an effort to further maximize the working space between the aortic valve V and theocclusion balloon826 the geometry of theocclusion balloon826 has been modified so that it can be placed at the very apex of the aortic arch A without compromising blood flow to the brachiocephalic, common carotid or subclavian arteries. Theocclusion balloon826 has a generally cylindrical outer geometry modified with ahelical groove830 that starts at theproximal end834 of the balloon and spirals around theballoon826 in the distal direction. In this illustrative embodiment, thespiral groove830 forms approximately two complete turns encircling theocclusion balloon826 and is delimited by anannular ring828 that forms a seal with the aortic wall at the distal end of theballoon826 to isolate the heart and the coronary arteries the systemic blood flow which is supported by the cardiopulmonary bypass system. Thespiral groove830 forms a flow path for oxygenated blood from the descending aorta to the brachiocephalic, common carotid or subclavian arteries C.A spiral ridge832 that runs along thespiral groove830 contacts the aortic wall and stabilizes theinflated occlusion balloon826 to prevent unintended movement of theocclusion balloon812 without occluding blood flow to the head and neck arteries. This same effect can be accomplished using functionally equivalent balloon geometries. For instance, this effect could be achieved with a shaped balloon having an annular ring at the distal end of the balloon to seal against the aortic wall, isolating the heart and the coronary arteries from systemic blood flow, and a multiplicity of bumps or ridges at the proximal end to contact the aortic wall and stabilize the balloon, with the space between the bumps providing a blood flow path to the head and neck arteries branching from the aortic arch.
• Another aspect of the present invention is illustrated inFIGS. 25A and 25B. In this embodiment, the function of de-airing the heart and the ascending aorta at the completion of the interventional procedure has been combined with theendoaortic partitioning catheter130. Thecatheter130 is configured so that thedistal tip131 of the catheter is positioned near the anterior wall of the ascending aorta B. This can be accomplished by making acurve132 in the distal portion of the catheter shaft that brings thetip131 of the catheter near the anterior wall of the ascending aorta B, as shown inFIG. 25A. Alternatively, theocclusion balloon134 can be shaped so that when theballoon134 is inflated, thedistal tip135 of thecatheter133 is directed toward the anterior wall of the ascending aorta B, as shown inFIG. 25B. The advantage of this modification of the endoaortic partitioning catheter is that, when the patient is placed in a supine position, the distal tip of the catheter is at the highest point in the ascending aorta so that any air bubbles that enter the heart, the coronary arteries or the aortic root during the course of surgery can be vented out through a lumen in the catheter prior to deflating the occlusion balloon to reverse the cardioplegic arrest.
• FIG. 26 shows another application of shaped balloons for the purpose of centering the tip137 of theendoaortic partitioning catheter136 within the ascending aorta B. Theexpandable occlusion balloon138 has a distal occlusion means139 with an expanded diameter sufficient to occlude the ascending aorta B and a proximal stabilizing means140 with an expanded diameter sufficient to contact the inner surface of the ascending aorta B. Between the occlusion means139 and the stabilizing means140 is an area ofreduced diameter141. When expanded, the occlusion means139 blocks substantially all systolic and diastolic blood flow through the ascending aorta B. The stabilizing means140 contacts the inner surface of the ascending aorta B and orients thedistal segment142 of the catheter shaft so that it is parallel with the axis of the ascending aorta B, reliably centering thecatheter tip143 within the aortic lumen just superior to the aortic root R.
• One particular embodiment for achieving this geometry is shown inFIG. 26. In this embodiment, theocclusion balloon138 has a dumbbell shape when expanded. The occlusion means is provided by adistal lobe139 of the dumbbell shapedballoon138, and the stabilizing means is provided by aproximal lobe140 of the balloon, with awaist141 of reduced diameter between the proximal140 and distal139 lobes. The dumbbell shapedocclusion balloon138 thus has two rings of contact with the inner surface of the ascending aorta B for better stabilization and orientation of the balloon in the proper position. Additional advantages of this configuration are that by providing two rings of contact with the inner surface of the ascending aorta B, the dumbbell shapedballoon138 can achieve a better and more reliable seal and greater resistance to displacement of the inflated balloon.
• Another particular embodiment for achieving a similar geometry would have two separate, but closely spaced, expandable balloons mounted on the distal segment of the catheter shaft. When expanded, the more distal balloon serves as an occlusion means, and the more proximal balloon serves as a stabilizing means for orienting the distal segment of the catheter parallel to the axis of the aortic lumen. It should be noted that the stabilizing means need not occlude the ascending aorta. However, for proper effect, it should contact the inner surface of the ascending aorta at at least three points around the inner circumference of the ascending aorta. Thus, the stabilizing means may have other non-spherical geometries that do not fully occlude the ascending aorta. For instance, multiple smaller balloons could be mounted circumferentially around the catheter shaft so that, when the balloons are inflated, they contact the inner surface of the ascending aorta at at least three points. Likewise, an expandable, non-balloon stabilizing means can also be used for contacting the inner surface of the ascending aorta for stabilizing and orienting the distal tip of the catheter.
• Another approach to centering the distal tip of the endoaortic partitioning catheter within the ascending aorta, shown inFIG. 27, works independently of balloon geometry. In this embodiment, thedistal tip145 of theendoaortic partitioning catheter144 is made steerable by one ormore control wires146,147 extending from the proximal end of thecatheter144 to the distal end through one or more lumens in the side wall of thecatheter shaft148. The distal end of thecontrol wires146,147 connect to a rigid ring or other anchoring device embedded in the wall of thecatheter shaft148 near thedistal tip145 of thecatheter144. The proximal end of thecontrol wires146,147 connect to a control means149 at the proximal end of the catheter. Forcatheters144 having one degree of freedom (i.e. 1-2 control wires) in the steerability of thedistal tip145, the control means149 can be a control knob or lever or similar control device. Forcatheters144 having two degrees of freedom (i.e. 4 or more control wires) in the steerability of thedistal tip145, the control means149 can be a joy stick or similar control device. Theshaft148 of the catheter should be made with a flexibledistal segment150 which is relatively more flexible than the proximal portion of thecatheter shaft148. This concentrates the deflection of the catheter shaft in thedistal section150 when one or more of thecontrol wires146,147 are tensioned by the control means149 to steer thedistal tip145 of thecatheter144.
• The steering mechanism can be used to deflect thedistal tip145 of the catheter shaft away from the aortic wall as the catheter is advanced through the aortic arch A and into the ascending aorta B. This reduces the likelihood of any trauma caused to the aortic wall by the catheterization and reduces the chances of dislodging any calcifications or other emboli from the aortic wall as thecatheter144 passes. Once thecatheter144 is in place in the ascending aorta B and theocclusion balloon151 is inflated, the position of thecatheter tip145 can be verified fluoroscopically and the steering mechanism used to direct thetip145 of the catheter toward the center of the aortic lumen in spite of any curvature in the ascending aorta B or eccentricities in theocclusion balloon151. If any diagnostic or therapeutic instruments are to be delivered through theinner lumen152 of theendoaortic partitioning catheter144 the steering mechanism can be used for centering thedistal tip145 of thecatheter144 with respect to the aortic valve V or for directing the instruments to other anatomical features within the heart or the aortic root R. The steering mechanism can also be used for directing thecatheter tip145 toward the anterior wall or the highest point in the ascending aorta for de-airing the heart and the ascending aorta at the completion of the interventional procedure before deflating the occlusion balloon to reverse the cardioplegic arrest, as described above in relation toFIG. 25.
• Another aspect of the present invention is illustrated inFIG. 28. In this embodiment, afiberoptic illumination device153 has been combined with theendoaortic partitioning catheter154. Thefiberoptic illumination device153 can serve two distinct purposes. The first function of thefiberoptic illumination device153 can be for transillumination of the aortic wall W for detecting plaque and calcifications P in the aortic wall and for identifying the optimal point for creating a proximal anastomosis of a coronary bypass vein graft. In this embodiment, afiberoptic bundle155 is extended through theshaft156 of theendoaortic partitioning catheter154 to the distal end. Thefiberoptic bundle155 may be built into the wall of thecatheter shaft156 or a separatefiberoptic bundle155 can be removably inserted through the infusion lumen of thecatheter154. At the distal end of thefiberoptic bundle155 is alight diffuser157 or a means for directing a broad lateral beam of light. The proximal end of the fiberoptic bundle is connected to a high intensity source ofvisible light158. When the light beam or diffuse illumination passes through the wall W of the aorta, calcifications and heavy atherosclerotic plaque P can be detected as shadows in the aortic wall W. The exterior of the aorta can be observed with a thoracoscope inserted through an intercostal access port into the patient's chest. The light source for the thoracoscope should be turned off while performing the transillumination so that the light coming through the aortic wall can be clearly seen. When this technique is used in open-chest bypass surgery, the lights in the operating room should be dimmed so that the light coming through the aortic wall can be seen. A clear, brightly lit section of the aortic wall W without shadows will indicate a relatively plaque free area of the aorta suitable for making the distal anastomosis. If a separatefiberoptic bundle155 is inserted through the infusion lumen of thecatheter154, it can be manipulated from outside of the patient's body to scan the entire ascending aorta B to find the optimum anastomosis site or to find multiple anastomosis sites for multi-vessel bypass operations.
• The second function of thefiberoptic illumination device153 can be for facilitating placement of theendoaortic partitioning catheter154 without the need for fluoroscopic guidance. In this embodiment, afiberoptic bundle155 is extended through theshaft156 of theendoaortic partitioning catheter154 to the distal end. Again, thefiberoptic bundle155 may be built into the wall of thecatheter shaft156 or a separatefiberoptic bundle155 can be removably inserted through the infusion lumen of thecatheter154. Located at the distal end of thefiberoptic bundle155 is ameans157 for directing a narrow lateral beam of light to create a spot or a 360° ring of light around the tip of the catheter. The proximal end of thefiberoptic bundle155 is connected to a high intensity source ofvisible light158. When theendoaortic partitioning catheter154 is inserted into the ascending aorta B, the position of the catheter tip can be determined by the position of the spot or ring of light where it shines through the aortic wall W. When theendoaortic partitioning catheter154 is in the correct position, theocclusion balloon159 can be inflated and a cardioplegic agent infused to arrest the heart.
• These two functions of thefiberoptic illumination device153 can be combined into one device if the optical elements are chosen to deliver a beam which is a compromise between the broad beam needed for aortic wall transillumination and the narrow beam preferred for the catheter location function. Alternatively, an optical system could be chosen which is selectively capable of delivering a broad or narrow lateral beam of light.
• In other alternatively embodiments, theocclusion balloon158 can be illuminated from the interior with thefiberoptic illumination device153 to monitor balloon placement, inflation and migration. The effectiveness of the illumination can be enhanced by incorporating reflective or fluorescent material in the balloon or the inflation fluid.
• Being able to detect the precise position of theendoaortic partitioning catheter154 without the need for fluoroscopic imaging has the potential of simplifying the catheter placement procedure and the equipment needed in the operating room. Other non-fluoroscopic means for detecting the position of the catheter tip include placing a metallic or magnetic marker at the tip of the catheter and using a thoracoscopically placed Hall effect proximity detector or magnetometer in the chest cavity to detect the position of the catheter tip through the aortic wall. Another means of detecting the position of the catheter tip within the ascending aorta is by ultrasonic imaging. An endoscopic ultrasonic imaging probe can be introduced through an access port in the chest or a transoesophageal ultrasound probe can be used. The imaging of the catheter can be enhanced by placing an echogenic marker near the tip of the catheter. A material with significantly higher or lower acoustic impedance than the catheter and the surrounding tissue and blood can serve as an echogenic marker. For example, a metal ring with a roughened exterior surface or an air-filled pocket or ring of closed cell foam mounted on or embedded in the tip of the catheter will serve as an echogenic marker. The catheter tip can be observed with ultrasonic imaging as the catheter is advanced into the ascending aorta to assure proper placement of the occlusion balloon.
• Another approach for facilitating placement of the endoaortic partitioning catheter without the need for fluoroscopic guidance is illustrated inFIG. 29. This embodiment of the endoaortic partitioning catheter160 has a secondexpandable member161 mounted on the distal end of the catheter distal to the firstexpandable occlusion member162. In a particular embodiment, the distalexpandable member161 is an inflatable balloon having aproximal balloon neck163 which is attached to thecatheter shaft166 and adistal balloon neck164 which is inverted and attached to thedistal tip165 of the catheter shaft. When the distalexpandable member161 is inflated, it expands to surround and protect thedistal tip165 of the catheter. If an expandable balloon is used for the firstexpandable occlusion member162 the first162 and second161 expandable members can be inflated through a single inflation lumen within thecatheter shaft166. Preferably, however a separate second inflation lumen is provided for individually inflating the distalexpandable member162. The distalexpandable member162 preferably has a smaller expanded diameter than the firstexpandable occlusion member161 so that it does not occlude the lumen of the ascending aorta B.
• In operation, the endoaortic partitioning catheter160 is inserted and advanced into the descending aorta D. Then, the distalexpandable member161 is inflated to act as a soft protective bumper for thedistal end165 of the catheter160. The catheter160 can be advanced over the aortic arch A and into the ascending aorta B with very little concern about causing trauma to the aortic wall or dislodging any calcifications or other emboli from the aortic wall as the catheter passes. When the catheter160 is in the ascending aorta B, it is advanced slowly until the distalexpandable member161 comes into contact with the aortic valve V. The soft cushion provided by the inflated distalexpandable member161 prevents any damage to the aortic valve V. The operator will be able to feel that the catheter160 has stopped advancing from the proximal end of the catheter which is outside of the patient's body and will know that the firstexpandable occlusion member162 is in proper position in the ascending aorta B between the coronary ostia and the brachiocephalic artery without the need for fluoroscopic verification. The firstexpandable occlusion member162 can be inflated to occlude the ascending aorta B and a cardioplegic agent infused through the perfusion lumen that exits the catheter through aport167 distal to the firstexpandable occlusion member162.
• FIGS. 30A and 30B are detail drawings of an additional feature of the invention which is a frictionallocking suture ring900 for use with the endoaortic partitioning catheter. For indwelling catheters, such as the endoaortic partitioning catheter, it is often desirable to fasten the catheter to the patient or to the surgical drapes to prevent undesired migration or dislodgement of the catheter from its correct position. The frictionallocking suture ring900 ofFIGS. 30A and 30B is provided as part of the invention to facilitate anchoring the catheter in place to avoid unintentional movement of the catheter after it has been positioned in the ascending aorta. Typical suture rings on introducer sheaths, central venous catheters and other indwelling catheters are located at a fixed position near the proximal hub of the catheter. This is generally adequate for catheters where the precise placement of the distal tip of the catheter is not critical. With the endoaortic partitioning catheter, however, the precise placement of the distal tip of the catheter within the ascending aorta is highly critical and the distance from the point of insertion of the catheter into the peripheral arterial access site to the ascending aorta is highly variable from patient to patient. Therefore, a standard, fixed-position suture ring would be wholly inadequate in the present application. The frictional locking suture ring ofFIGS. 30A and 30B allows the endoaortic partitioning catheter to be precisely positioned and reliably anchored in place with any desired length of the catheter shaft inserted at the access site.
• The frictionallocking suture ring900 is preferably made from atube902 of a resilient, high-tack polymer, preferably an extrudable or injection moldable thermoplastic elastomer, such as a thermoplastic polyurethane with a hardness in the range of 70-90 Shore A durometer or Kraton™ (Shell Chemical Co.) thermoplastic elastomer with a hardness of about 40 Shore A durometer. The length of thetube902 is typically from 2-3 cm. The internal diameter of thetube902 is slightly larger than the external diameter of the shaft of the endoaortic partitioning catheter920. In an exemplary embodiment for use with a 4 mm diameter or 12 French catheter, the internal diameter of thetube902 is preferably about 4.5-4.8 mm, providing a diametrical clearance of approximately 0.5-0.8 mm. The external diameter of thetube902 is typically about 6.5-7.0 mm. There is alongitudinal slot904 about 1.2-2.0 mm wide through the side of thetube902.
• The frictionallocking suture ring900 is placed over the exterior of the endoaortic partitioning catheter920 with the shaft of the catheter running through the lumen of the tube. Because of the diametrical clearance between the exterior of the catheter920 and the interior of thetube902, thesuture ring900 is free to move along the length of the catheter920. However, when asuture906 or other ligature is tied around thesuture ring900, thetube902 compresses around the exterior of the catheter920 and the high friction due to the tackiness of the suture ring material creates a firm, nonslip grip on the catheter shaft920. To facilitate securing thesuture906 to thesuture ring900, acircumferential groove908 is provided on the exterior of thetube902. In the illustrative embodiment shown inFIGS. 30A and 30B, there are threecircumferential grooves908 around the tube at positions near the proximal end, the center and the distal end of thelongitudinal slot904 to provide places for tying asuture906 around thesuture ring900. In an injection molded embodiment of thesuture ring900, other suture attachment means, such as one or more eyelets, can easily be provided on the exterior of thetube902.
• In order to increase the frictional grip between the frictionallocking suture ring900 and the shaft of the endoaortic partitioning catheter920, a strip ofhigh friction material910 may be provided on the interior of thetube902. In the illustrative embodiment ofFIGS. 30A and 30B a 1.0 mm wide strip ofhigh friction tape910 has been adhesively bonded to the interior of thetube902. A suitable material for use in this application is a self-adhesive high friction tape available from 3M Manufacturing Co., Inc. which is made of a polyurethane film with mineral particles embedded in the exterior surface to enhance the frictional properties. Thehigh friction tape910 is mounted in thetube902 with the high friction gripping surface oriented toward thelumen912 of thetube902. When asuture906 is tied around the exterior of the frictionallocking suture ring900, the high friction surface of thetape910 is pressed against the exterior of the catheter shaft920 to increase the grip on the catheter.
• Preferably, the frictionallocking suture ring900 is placed over the catheter shaft from the distal end during manufacturing. In use, thesuture ring900 initially resides in an out of the way position at the proximal end of the catheter near the proximal hub while the catheter920 is being introduced and maneuvered into position within the patient's aorta. Once the distal end of the catheter has been maneuvered to the proper position, the catheter920 can be secured in position by sliding thesuture ring900 along the catheter shaft920 until it is close to the introduction site. Asuture906 is tied around exterior of thesuture ring900 to create a frictional grip between thesuture ring900 and the catheter shaft920. Thesuture906 is then stitched through the patient's skin close to the insertion site and tied. This securely fastens the catheter920 in the desired position relative to the patient's body with the correct length of catheter inserted into the patient's vasculature. If preferred, separate sutures can be used for tying thesuture ring900 and stitching it to the patient. Alternatively, thesuture ring900 can be secured to the surgical drapes covering the patient, though this is less preferred because there can be relative movement between the drapes and the catheter introduction site that could result in movement of the catheter from its desired position.
• If it becomes necessary to reposition the catheter920 at any time during the procedure, the frictional grip can be released by untying or cutting thesuture906 around thesuture ring900. The catheter920 can be repositioned by sliding it through thelumen912 of the suture ring and then it can be secured in the new position by retying thesuture906 around thesuture ring900. When it is time to remove the catheter920, thesuture906 fastening thesuture ring900 to the patient can be cut and thesuture ring900 withdrawn with the catheter920.
• In a further aspect of the invention, illustrated inFIGS. 30-34, theendoaortic partitioning catheter895 is coupled to anarterial bypass cannula850 that is specially adapted to serve as a dual purpose arterial bypass cannula and introducer sheath so as to allow thecatheter895 and thecannula850 to be introduced through the same arterial puncture. The smaller diameter endoaortic partitioning catheters made possible by the embodiments described in relation toFIGS. 5-9, are particularly suitable for use in combination with the specialarterial bypass cannula850. Thearterial bypass cannula850 is configured for connection to a cardiopulmonary bypass system for delivering oxygenated blood to the patient's arterial system. Thearterial bypass cannula850, shown inFIG. 31, has acannula body851 which is preferably made of a transparent, flexible, biocompatible polyurethane elastomer or similar material. In one preferred embodiment, thecannula body851 has a 45° beveleddistal end853, aproximal end852, ablood flow lumen857 extending between theproximal end852 and thedistal end853, and anoutflow port891 at thedistal end853. Alternatively, thecannula body851 can have a straight cut distal end with chamfered or rounded edge. Optionally, a plurality of additional outflow ports may be provided along the length ofcannula body851, particularly neardistal end853. Thecannula body851 is tapered from theproximal end852 to thedistal end853 and, in one preferred embodiment, the taperedcannula body851 is reinforced with a coil of flatstainless steel wire854 embedded in the wall of thecannula body851. Adjacent to theproximal end852 of thecannula body851, proximal to the reinforcingcoil851, is aclamp site851 which is a flexible section of thetubular cannula body851 that can be clamped with an external clamp, such as a Vorse type tube occluding clamp, forming a hemostatic seal to temporarily stop blood flow through thelumen857 of thecannula850. In a preferred embodiment, thecannula body851 has a length between about 10 cm and 60 cm, and preferably between about 12 cm and 30 cm. In one particular embodiment, thecannula body851 has a distal external diameter of approximately 7 mm or 21 French (Charrière scale) and a distal internal diameter of approximately 6.0 mm or 18 French. In a second particular embodiment, thecannula body851 has a distal external diameter of approximately 7.7 mm or 23 French (Charrière scale) and a distal internal diameter of approximately 6.7 mm or 20 French. Preferably, theproximal end852 of thecannula body851 of either embodiment has an internal diameter of approximately {fraction (3/8)} inch or 9.5 mm. The choice of which embodiment of thearterial bypass cannula850 to use for a given patient will depend on the size of the patient and the diameter of the artery chosen for the arterial cannulation site. Generally, patients with a larger body mass will require a higher infusion rate of oxygenated blood while on cardiopulmonary bypass, therefore the largerarterial bypass cannula850 should be chosen if the size of the artery allows.
• Anadapter assembly865 is connected to theproximal end852 of thecannula body851. In one preferred embodiment, theadapter assembly865 and thecannula body851 are supplied preassembled as a single, sterile, ready-to-use unit. Alternatively, theadapter assembly865 can be packaged and sold as a separate unit to be connected to thecannula body851 at the point of use. Theadapter assembly865 has a Y-fitting858 which is connected to theproximal end852 of thecannula body851. The Y-fitting858 has a first branch ending in abarbed connector859 which is configured for fluid connection totubing892 from a cardiopulmonary bypass system, as shown inFIG. 34. To prepare thearterial bypass cannula850 for insertion into a peripheral artery, such as a patient's femoral artery or brachial artery, by an arterial cutdown or by a percutaneous Seldinger technique, aconnector plug871, which is molded of a soft, elastomeric material, is placed over thebarbed connector859. Atapered dilator867 is passed through a wiper-type hemostasis seal872 in theconnector plug871. The wiper-type hemostasis seal872 is a hole through theelastomeric connector plug871 that has a slight interference fit with the external diameter of thedilator867. A series of ridges can be molded within thehemostasis seal872 to reduce the sliding friction on thedilator867 while maintaining a hemostatic seal. Thedilator867 has a tapereddistal tip869, aproximal hub870 with a luer lock connector, and aguidewire lumen879, sized for an 0.038 inch diameter guidewire, that runs from thedistal tip869 to theproximal hub870. The diameter of thedilator867 is such that thedilator867 substantially fills thecannula lumen857 at thedistal end853 of thecannula body851. The length of thedilator867 is such that thedistal tip869 of thedilator867 extends approximately 2 to 5 cm, and more preferably 4 to 5 cm, beyond thebeveled end853 of thecannula body851 when thedilator hub870 is against theconnector plug870. Thedilator867 may assume abend873 in it at the point where thedilator867 passes through the Y-fitting858 when thedilator867 is fully inserted. One ormore depth markers874,875 can be printed on thedilator867 with a nontoxic, biocompatible ink. Onedepth marker874 may be placed so that, when themarker874 is just proximal to thehemostasis seal872 on theelastomeric connector plug871, the tapereddistal tip869 of thedilator867 is just emerging from thebeveled end853 of thecannula body851. In one particular embodiment, thetapered dilator867 is made of extruded polyurethane with a radiopaque filler so that the position of the dilator can be verified fluoroscopically.
• A second branch of the Y-fitting858 is connected to anextension tube862 which terminates in ahemostasis valve876 configured to receive theendoaortic partitioning catheter895 therethrough. Theextension tube862 has a flexible middle section which serves as aproximal clamp site864 that can be clamped with an external clamp, such as a Vorse type tube occluding clamp, forming a hemostatic seal to temporarily stop blood flow through thelumen863 of theextension tube862. Thelumen863 of theextension tube862 between theproximal clamp site864 and thehemostasis valve876 serves as acatheter insertion chamber866, the function of which will be more fully explained in connection withFIG. 33.
• In a preferred embodiment of thearterial bypass cannula850, thehemostasis valve876 is a type of compression fitting known in the industry as a Tuohy-Borst adapter. The Tuohy-Borst adapter876 is shown in greater detail inFIG. 32. The Tuohy-Borst adapter876 has a compressible tubular or ring-shapedelastomeric seal883 that fits within acounterbore879 in thefitting body877. Theelastomeric seal883 is preferably made from a soft, resilient, self-lubricating elastomeric material, such as silicone rubber having a hardness of approximately 20-50 and preferably 40-50 Shore A durometer. Theelastomeric seal883 has acentral passage884 with abeveled entry885 on the proximal end of thepassage884. Theelastomeric seal883 has a beveleddistal surface886 angled at about 45° which fits against atapered seat880 in the bottom of thecounterbore879 that is angled at about 60°. A threadedcompression cap887 screws onto thefitting body877. The threadedcap887 has atubular extension887 which fits within thecounterbore879 in thefitting body877. An externally threadedsection888 on the proximal end of thetubular extension887 engages an internally threadedsection881 within the proximal end of thecounterbore879. When the threadedcap887 is screwed down onto thefitting body877, thetubular extension889 bears on theelastomeric seal883 forcing it against thetapered seat880 of thecounterbore879. The resultant force on theelastomeric seal883 squeezes theelastomeric seal883 inward to close off the passage central884 to make a hemostatic seal. When the threadedcap887 is unscrewed again from thefitting body877, thecentral passage884 of theelastomeric seal883 opens up again. The deliberate 15° mismatch between the angle of the beveleddistal surface886 of theelastomeric seal883 and thetapered seat880 of thecounterbore879 prevents theelastomeric seal883 from binding and causes thecentral passage884 to open up reliably when the threadedcap887 is unscrewed from thefitting body887. Aninternal ridge890 within the threadedcap887 engages in a snap fit with anexternal ridge882 on the proximal end of thefitting body877 to keep the threadedcap887 from being inadvertently separated from thefitting body877 if the threadedcap887 is unscrewed to the point where thethreads888,881 are no longer engaged.
• In one particular embodiment, thecentral passage884 of theelastomeric seal883 has an internal diameter of about 5 mm to allow clearance for inserting acatheter895 with a shaft diameter of 3-4 mm through the Tuohy-Borst adapter876 without damaging theocclusion balloon896 mounted on it. The Tuohy-Borst adapter876 is adjustable through a range of positions, including a fully open position for inserting theballoon catheter896, a partially closed position for creating a sliding hemostatic seal against theshaft897 of thecatheter895, and a completely closed position for creating a hemostatic seal with no catheter in thecentral passage884. In an alternative embodiment, thecentral passage884 of theelastomeric seal883 can be sized to have a slight interference fit with theshaft897 of thecatheter895 when uncompressed. In this embodiment, the Tuohy-Borst adapter876 has positions which include a fully open position for creating a sliding hemostatic seal against theshaft897 of thecatheter895, and a completely closed position for creating a hemostatic seal with no catheter in thecentral passage884. In a second alternative embodiment, a separate ring-like wiper seal (not shown) is added in series with the Tuohy-Borst adapter876 to create a passive sliding hemostatic seal against theshaft897 of thecatheter895 without the necessity of tightening the threadedcap887. Additionally, the Tuohy-Borst adapter876, in either embodiment, may have a tightly closed position for securing thecatheter shaft897 with respect to the patient. In other alternative embodiments, other known hemostasis valves may be substituted for the Tuohy-Borst adapter876 as just described.
• In a particularly preferred embodiment, the internal surface of thelumen863 of theextension tube862 and/or the internal surface of thelumen857 of thecannula body851 are coated with a highly lubricious biocompatible coating, such as polyvinyl pyrrolidone, to ease the passage of theendoaortic partitioning catheter895, and especially theocclusion balloon896, through these lumens. Other commercially available lubricious biocompatible coatings can also be used, such as Photo-Link™ coating available from BSI Surface Modification Services of Eden Prairie, Minn.; sodium hyaluronate coating available from Biocoat of Fort Washington, Pa.; proprietary silicone coatings available from TUA of Sarasota, Fla.; and fluid silicone or silicon dispersions. Similarly, a distal portion of the exterior of thecannula body851 can be coated with one of these lubricious biocompatible coatings to facilitate insertion of thearterial bypass cannula850 into the artery at the cannulation site. Furthermore, theendoaortic partitioning catheter895 itself, in any of the embodiments described herein, can be coated with one of these lubricious biocompatible coatings to facilitate its insertion and passage through thearterial bypass cannula850 and the patient's vasculature. Preferably, theocclusion balloon896 of theendoaortic partitioning catheter895 should be free of any lubricious coating so that there is sufficient friction between the expanded occlusion balloon and the interior aortic wall to prevent accidental dislodgement or migration of theocclusion balloon896.
• In operation, thearterial bypass cannula850 is prepared for insertion as shown inFIG. 31, with thetapered dilator867 in place in theblood flow lumen857 of thecannula body851 and with the Tuohy-Borst fitting876 completely closed. An arterial cutdown is made into an artery, preferably the patient's femoral artery, at the cannulation site or a guidewire is placed percutaneously using the Seldinger technique and thedilator867 and thedistal end853 of thecannula body851 are inserted into the lumen of the artery with the bevel up. Asuture894 can be tied around theartery893 where thecannula body851, as shown inFIG. 33, inserts to avoid bleeding from theartery893 at the cannulation site. Thedilator867 is then withdrawn from thecannula body851, allowing blood to flash back and fill thelumen857 of thecannula body851. When thetip868 of thedilator867 is proximal to thedistal clamp site856 an external clamp is applied to thedistal clamp site856 to stop further blood flow. Thedilator867 is completely withdrawn and theconnector plug871 is removed so that atube892 from the cardiopulmonary bypass system can be attached to thebarbed connector859 of the Y-fitting858, as shown inFIG. 33. Air is bled from thearterial bypass cannula850 by elevating theextension tube862 and opening the Tuohy-Borst fitting876 slightly and releasing the external on thedistal clamp site856 to allow the blood to flow out through the Tuohy-Borst fitting876. Alternatively, air can be bled out of thearterial bypass cannula850, through an optional vent fitting with a luer cap (not shown) that can be provided on the Y-fitting858 or an infusion line and a three-way stopcock. The optional vent fitting can be also used as a port for monitoring perfusion pressure within thearterial bypass cannula850. Once the air is bled out of the system, the external clamp can be removed from thedistal clamp site856 the cardiopulmonary bypass system pump can be turned on to perfuse the patient's arterial system with oxygenated blood at a rate of about 3 to 6 liters/minute, preferably at a pump pressure of less than about 500 mmHg.
• To introduce theendoaortic partitioning catheter895 into thearterial bypass cannula850, anexternal clamp891 is placed on theproximal clamp site864, as shown inFIG. 33, to stop blood from flowing out through theextension tube862 and the Tuohy-Borst adapter876 is opened all the way by unscrewing the threadedcap887 to open up thepassage884 through theelastomeric seal883. The distal end of theendoaortic partitioning catheter895 with theocclusion balloon896 mounted thereon is inserted through thepassage884 of the Tuohy-Borst adapter876 into theinsertion chamber866 of thearterial bypass cannula850. Optionally, first andsecond depth markers898,899 may be printed on theshaft897 of theendoaortic partitioning catheter895 with a nontoxic, biocompatible ink. Thefirst depth marker898 on thecatheter895 indicates when theocclusion balloon896 is entirely distal to theelastomeric seal883. When thefirst depth marker898 is positioned just proximal to the threadedcap887, the Tuohy-Borst adapter876 should be tightened to create a sliding, hemostatic seal around thecatheter shaft897. Now, theclamp891 can be removed to allow thecatheter895 to be advanced distally through thearterial bypass cannula850.
• Before theendoaortic partitioning catheter895 enters theblood flow lumen857 within the Y-fitting858, the perfusion rate from the cardiopulmonary bypass system pump should be temporarily turned down to a rate of about 1 to 2 liters/minute to avoid hemolysis, tubing disruptions or other complications due to the additional flow resistance caused by theocclusion balloon896 as it passes through theblood flow lumen857. Thecatheter895 can now be advanced distally until the occlusion balloon986 is distal to thedistal end853 of thecannula body851. Asecond depth marker899 on thecatheter895 indicates when theocclusion balloon896 is entirely distal to thedistal end853 of thecannula body851. When thesecond depth marker898 reaches the proximal end of the threadedcap887, as shown inFIG. 33, the perfusion rate from the cardiopulmonary bypass system pump should be returned to a rate of about 3 to 6 liters/minute. Theendoaortic partitioning catheter895 can now be advanced into the ascending aorta for partitioning the heart and inducing cardioplegic arrest according to the methods described above. When theendoaortic partitioning catheter895 is in position within the ascending aorta the Tuohy-Borst adapter876 can be tightened around thecatheter895 to act as a friction lock to hold the catheter in place.
• After completion of the surgical procedure on the heart, theendoaortic partitioning catheter895 can be removed from thearterial bypass cannula850 by reversing the sequence of operations described above. Thearterial bypass cannula850 can remain in place until the patient has been weaned from cardiopulmonary bypass, then thearterial bypass cannula850 can be removed and the arterial puncture site repaired.
• It should be noted that for the venous side of the cardiopulmonary bypass system, a similar dual purpose venous bypass cannula and introducer sheath with the above-described features can be used for accessing the femoral vein and for introducing a venting catheter or other devices into the venous side of the circulatory system. In a venous configuration the dual purpose venous bypass cannula and introducer sheath preferably has an external diameter of about 21 to 32 French units, an internal diameter of about 18 to 30 French units, and a length of about 50 to 75 cm.
• FIGS. 35A-35C illustrate another means of steering thedistal tip171 of theendoaortic partitioning catheter170 for centering the catheter tip within the ascending aorta B. Theendoaortic partitioning catheter170 is shown positioned within the patient's aortic arch A inFIG. 35A. Thedistal tip171 of thecatheter170 is made steerable by amultichamber occlusion balloon172 mounted on thedistal portion173 of the catheter which is shown partially cut away inFIG. 35A. Thedistal portion173 of thecatheter170 has a distal curve which may be a 180°±45° arc or a 270°±45° arc, as described in previous embodiments. Themultichamber occlusion balloon172 has afirst chamber174 and asecond chamber175. Theballoon172 is mounted so that thefirst chamber174 is oriented toward the outside of the distal curve and thesecond chamber175 is oriented toward the inside of the distal curve. Afirst inflation lumen176 in thecatheter170 connects to thefirst chamber174 through afirst inflation port178. Asecond inflation lumen177 in thecatheter170 connects to thesecond chamber175 through asecond inflation port179. Aninfusion lumen181 connects with one ormore infusion ports182 at thedistal tip171 of thecatheter170.
• As shown in the cross section of the deflatedocclusion balloon172 inFIG. 35B, apartition wall180 separates the first174 and second175 chambers of theballoon172. The first174 and second175 chambers of theballoon172 may be differentially inflated through theinflation lumens176,177. For example, the cross section ofFIG. 35C shows thefirst chamber174 of themultichamber occlusion lumen172 inflated to a greater degree than thesecond chamber175. Because thefirst chamber174 is oriented toward the outside of the distal curve of thecatheter170, thedistal tip171 of thecatheter170 is forced toward the inside of the aortic arch A, that is, toward the left side of the patient, as inFIG. 35A. Alternatively, thesecond chamber175 can be inflated to a greater degree than thefirst chamber174 to force thedistal tip171 of thecatheter170 toward the outside of the aortic arch A, that is, toward the right side of the patient. Thus, thedistal tip171 of thecatheter170 can be steered to center thetip171 within the lumen of the ascending aorta B under fluoroscopic observation by inflating and deflating the individual chambers of themultichamber occlusion balloon172. It should be noted that themultichamber occlusion balloon172 is not limited to only two chambers. Themultichamber occlusion balloon172 can be made with three, four or more chambers to give thedistal tip171 greater degrees of steerability.
• It should be noted that while several aspects of the present invention have been illustrated and discussed separately in the foregoing description, many of these aspects can be advantageously combined into a single, multifunction embodiment. As an illustrative example,FIG. 36 shows a multifunction embodiment of theendoaortic partitioning catheter960 combining several of the inventive aspects previously discussed. Theshaft964 of thecatheter960 has a coaxial construction with an inner961 and outer962 tubular member, similar to the embodiments described in connection withFIGS. 5A-5D and6A-6D. Thecatheter shaft964 may be made with varying degrees of stiffness along the length of theshaft964, culminating in a softatraumatic tip965 which may be highly loaded with a radiopaque filler. Thecatheter shaft964 may be made with a precurveddistal portion966 similar toFIGS. 10A-10B, or with a precurveddistal portion966 which is out of plane with the proximal portion of thecatheter shaft964, as inFIGS. 11A-11B. Anexpandable occlusion balloon963 is mounted on thedistal portion966 of thecatheter shaft964. Theocclusion balloon963 preferably has a low profile deflated state with an ellipsoidal shape, similar to that shown inFIG. 6A. In addition, theocclusion balloon963 may have an eccentric or asymmetricalinflated profile963′, similar to any of the embodiments discussed in relation toFIGS. 14-26, orFIG. 35 which would also provide a steering means for the distal tip of the catheter, as would the steering mechanism ofFIG. 27.
• Theocclusion balloon963 is mounted with itsdistal balloon neck967 attached to the innertubular member961 and its proximal balloon neck attached to the outertubular member962. The innertubular member961 is attached at its proximal end to afirst hub971 and the outertubular member962 is attached at its proximal end to a second969hub971 which are axially slidably and/or rotatable with respect to one another, similar to the embodiments described in relation toFIGS. 8A-8D and9A-9B. An infusion fitting977, such as a luer lock, on thefirst hub971 is connected to aninfusion lumen978 which terminates at the distal end of thecatheter960. An inflation fitting970, preferably a luer lock, on thesecond hub971 is connected to aninflation lumen979 defined by an annular space between the inner961 and outer962 tubular members which communicates with the interior of theocclusion balloon963.
• Thesecond hub969 may be moved proximal and/or rotated with respect to thefirst hub971 to minimize the deflated profile of theocclusion balloon963. The lower deflated profile of theocclusion balloon963 facilitates easy insertion of thecatheter960 through a dual function arterial cannula andintroducer sheath850, similar to that described in relation toFIGS. 31-34. When theendoaortic partitioning catheter960 is combined with the dual function arterial cannula andintroducer sheath850, theshaft964 of thecatheter960 should be made with an additional 20-25 cm of length for a total shaft length of approximately 100-115 cm. The diameter of thecatheter shaft964 should also be minimized as much as possible to reduce the amount of cross sectional area thecatheter shaft964 takes up in the blood flow lumen of thearterial cannula850. To this end, this combined embodiment is made with adistal pressure transducer972 and a balloonpressure monitoring transducer973 mounted on the innertubular member961, as described in relation toFIGS. 7A-7C. Thedistal pressure transducer972 and the balloonpressure monitoring transducer973 are electrically connected to anelectrical connector974 on thefirst hub971. Also on thefirst hub971 is afiberoptic connector976 which connects to afiberoptic bundle975 which terminates with a means for directing a lateral beam of light at the distal end of thecatheter960 for aortic transillumination and/or for facilitating nonfluoroscopic placement of thecatheter960. Thefiberoptic bundle975 may also be made as a separate unit for insertion through theinfusion lumen978 of thecatheter960 to further reduce the catheter shaft diameter while maintaining maximum functionality. The diameter of thecatheter shaft964 can thus be reduced to as small as 8 to 10.5 French (2.7-3.5 mm diameter).
• Additionally theendoaortic partitioning catheter960 may be combined with a frictionallocking suture ring900 for anchoring thecatheter960 in the proper position after placement, as described in relation toFIGS. 30A-30B.
• Referring toFIG. 37, anotherpreferred balloon401 is shown which includes surface features for reducing migration of theballoon401. Theballoon401 includes an outer surface having a first, low-friction portion403 and a second, high-friction portion405. The second, high-friction portion405 includes a number ofshort ribs407 and aselective coating409 which enhance the frictional engagement between theballoon401 and the aortic lumen relative to the frictional engagement between thefirst portion403 and the aortic lumen. Theselective coating409 may be provided by masking thefirst portion403 and sandblasting thesecond portion405. Alternatively, the method described in PCT/US94/09489 may be used to provide thehigh friction portion405. Theballoon401 preferably has a substantially oval cross-sectional shape tapered in the distal and proximal directions, however, any balloon shape may be used.
• Referring to the end view ofFIG. 38, theballoon401 preferably includes at least three, and more preferably at least four,arms411 extending radially outward. A number of low-friction portions403 are positioned at radially-outward portions of thearms411. Thehigh friction portions405 are positioned between thelow friction portions403 so that when the balloon passes through a cylindrical body, such as a blood vessel, the low-friction portions403 contact the vessel while the first, high-friction portions405 do not. Theballoon401 is preferably evacuated prior to insertion into the patient at which time it can be verified that theradially extending arms411 are present. Although it is preferred to provide the radially-extendingarms411, theballoon401 may be configured in any other fashion so long as thelow friction portions403 are at radially-outward positions relative to the exposed,high friction portions405.
• Theballoon401 is preferably introduced through thearterial bypass cannula850 ofFIGS. 31-36 although any other delivery system may be used. In order to pass theballoon401 through thearterial bypass cannula850, theballoon401 may be temporarily folded or wrapped around the shaft so that theballoon401 fits through thearterial bypass cannula850. Once theballoon401 passes through thearterial bypass cannula850, theballoon401 assumes the collapsed shape ofFIG. 38 so that thelow friction portions403, which are at the radially outward positions, engage the body passageway. Theballoon401 is then advanced in the patient to the desired location, such as the ascending aorta, and theballoon401 is inflated. Referring toFIG. 39, an end view of theballoon401 is shown with theballoon401 in an inflated condition. When theballoon401 is expanded, thehigh friction portions405 evert and are exposed for anchoring theballoon401. Although it is preferred to provide theselective coating409 and/orribs407, thefirst portion403 may include any other friction enhancing feature such as spiral ribs, knobs, cross-hatching, or a fine mesh. Furthermore, the first andsecond portions403,405 are preferably integrally formed, however, the first andsecond portions403,405 may be fabricated separately and attached to one another. Theballoon401 is mounted to ashaft413 having aninflation lumen415, aninfusion lumen417 and apressure lumen419 which are used in the manner described above when occluding the ascending aorta. Theballoon401 may, of course, be used in conjunction with any other catheter design disclosed herein or otherwise known to one of ordinary skill in the art.
• Referring toFIGS. 40 and 41, anotherpreferred balloon401A is shown wherein like reference numbers are used to represent similar features disclosed in the embodiment ofFIGS. 37-39. Thefirst portions403A are also positioned at radially-outward positions of radially-extendingarms411A. Thesecond portions405A extend between thefirst portions403A and include a plurality ofribs407A and ahigh friction portion409. When theballoon401A expands, thesecond portions405A evert so that theballoon401A assumes a substantially cylindrical cross-section as shown inFIG. 39 with the both thelow friction portions403A andhigh friction portions409 exposed.
• Referring toFIG. 42, another preferred method of anchoring the balloon is shown. Aballoon501 is positioned in the ascending aorta withclamps503 positioned on both sides of theballoon501 for anchoring theballoon501 in the aorta. Eachclamp503 is sized to slightly compress the aorta so that theballoon501 cannot pass by theclamp503 when theballoon501 is inflated. Although it is preferred to provide twoclamps503, aclamp503 having two pairs of jaws may also be used. Furthermore, although it is preferred to provideclamp503 on both sides of theballoon501, asingle clamp503 may be used if migration in only one direction is a problem. When using only oneclamp503 which prevents upstream migration of the balloon, the catheter shaft may be tensioned to prevent downstream migration. Theclamps503 may be used in conjunction any of the occluding members described herein or with any other conventional occluding member such as mechanically deployed occluding members.
• Referring toFIG. 43, a plan view of theclamp503 is shown. Theclamp503 may also be any of the clamps disclosed in pending U.S. patent application Ser. No. ______ by inventors Donlon et al., filed Dec. 4, 1995, Attorney Docket No. TTC No. 14635-42/Heartport No. 039-CP, which is incorporated herein by reference. Theclamp503 includesjaws505,507 pivotally coupled together at apivot509. Thejaws505,507 are biased open by aspring511 and are locked usingratchet513. As shown, theclamp503 does not occlude the aorta but merely blocks migration of theballoon501. A deploying mechanism (not shown) is used to deploy and retrieve theclamp503.
• Referring toFIG. 44A, another preferred method of anchoring an occluding member is shown. The occluding member is preferably aballoon501A having an hour-glass shape with theclamp503 positioned around anindentation515 for anchoring theballoon501A in both directions. Theballoon501A preferably includes aninner wall516 at theindentation515. Referring toFIG. 44B, theinner wall516 hasholes517 therethrough for pressure communication between both sides of theinner wall516. Theinner wall516 is preferably inelastic or at least less elastic than the balloon material so that the cross-sectional shape of theballoon501A at the indentation remains substantially the same after theballoon501A has been inflated. Theclamp501A is preferably sized to slightly compress theballoon501A. An advantage of the embodiment ofFIG. 44A is that the cooperation of theballoon501A and clamp503 requires less distention or compression of the aorta than would otherwise be necessary when using only a clamp or balloon. Minimizing the overall deflection of the aorta may advantageously minimize plaque release.
• Referring toFIG. 45, a partial cut-away of anothervalve876A for use with thecannula850 is shown. Similar reference numbers are used to represent similar items presented in previously described embodiments and discussion of the similar items is omitted here. A shaft displacing mechanism is coupled to thevalve876A for displacing a catheter shaft positioned therein. As will be discussed in further detail below, the shaft displacing mechanism facilitates displacing the shaft so that the shaft engages the body passageway for anchoring the shaft which, in turn, anchors the occluding member. The shaft displacing mechanism can move in an inward direction, defined byarrow819, and an outward direction opposite to the inward direction. The shaft displacing mechanism may be used with any catheter and is particularly useful when used in conjunction with the shafts described below in connection withFIGS. 46-49.
• Referring still toFIG. 45, a threadedcoupling831couples body877A to the remainder of thecannula850 which is described in connection withFIGS. 31-36. Thebody877A includeslips833 which engageslots835 in thecannula850. Thelips833 andslots835 permit axial displacement of thebody877A but prevent rotation of thebody877A when the threadedcoupling831 is rotated. An o-ring837 seals a space between thebody877A andcannula850 so that fluid does not pass therebetween. The threadedcoupling831 has threads which engage thebody877A so that rotation of the threadedcoupling831 displaces thebody877A axially. In this manner, a shaft (not shown) which is positioned within the delivery cannula is displaced upon rotation of thecoupling831. Thebody877A also preferably includes first, second andthird indicators821,823,825 which are described in further detail below in connection with operation of the displacement mechanism. A spring (not shown) may also be provided to preload the shaft in the inward or outward directions. A spring-loaded mechanism would preferably include a displacement stop to limit displacement of the shaft if forces on the shaft exceed the spring preload.
• Referring now toFIGS. 45-49, operation of thedelivery cannula850 andvalve876A is now described. The threadedcoupling831 is initially registered with the second,intermediate indicator823 so that the threadedcoupling831 can be moved either inward or outward. After theshaft903 is inserted into the patient and the occludingmember901 is positioned at the desired location, such as the ascending aorta A, the occludingmember901 is expanded to occlude the aorta as shown inFIG. 46. At this time, the pressure forces in the aorta tend to force the occludingmember901 in the upstream direction. To resist the pressure forces on the occludingmember901, the threadedcoupling831 is rotated so that theshaft903 is moved in the inward direction. Thethird indicator825 helps the user determine the desired displacement of theshaft903 in the inward direction. A preferred range for the predetermined displacement is between 1 and 5 cm, and more preferably between 2 and 4 cm, from thesecond indicator823. When the shaft is displaced in the inward direction, afirst portion905 engages the radially outward wall RO. Theshaft903, which now engages the aortic lumen, anchors the occludingmember901 against upstream migration. Theshaft903 and occludingmember901 are preferably made of the same materials and have the same dimensions as the embodiments described above in connection withFIGS. 10-30.
• After cardiopulmonary bypass is established, the pressure forces at this time tend to force the balloon in the downstream direction. To resist these forces, the threadedcoupling831 is rotated so that theshaft903 moves in the outward direction. Thefirst indicator821 provides a predetermined displacement in the outward direction which is preferably between 1 and 6 cm, and more preferably between 2 and 4 cm, relative to thesecond indicator823. Referring toFIG. 47, asecond portion907 of theshaft903 engages the radially inner wall RI of the aortic lumen. Thesecond portion907 is preferably the radially inner wall of the hook-shaped portion. Although it is preferred to provide theindicators821,823,825, the threadedcoupling831 andbody877A may be sized so that the maximum displacements match the desired displacements. Furthermore, although it is preferred to provide a threaded displacement mechanism, any other conventional connection may be used such as a bayonet connection, a ratchet and pawl, or a slidable connection with a frictional lock.
• Referring toFIGS. 48 and 49, another preferred catheter is shown. Theshaft903A has afirst portion905A for engaging the radially outer wall RO of the aortic lumen (FIG. 48) and asecond portion907A for engaging the radially inner wall RI of the aortic lumen (FIG. 49). Athird portion909A also engages the radially outer wall RO to further resist balloon migration in the upstream direction. The second andthird portions907A,909A are positioned at first andsecond bends911A,913A. Thefirst bend911A is preferably between 3 and 12 cm, and more preferably between 5 and 10 cm, from thedistal end915A. A first substantially-straight section917A extends between the first and second bends and preferably has a length between 3 and 12 cm, and more preferably between 3 and 8 cm. A second, substantially-straight section919A extends from thesecond bend909A toward the proximal end. Although it is preferred to provide a straight section between the first andsecond bends911A,913A, a curved portion may also be provided.
• The embodiments ofFIGS. 46-49 preferably include a relatively stiffproximal section919,919A and a flexibledistal section921,921A connected to the proximal section. Referring toFIGS. 46-47, theproximal section919 is substantially straight and thedistal section921 includes the hook-shaped portion. Referring toFIGS. 48 and 49, theproximal section919A preferably terminates just before thefirst bend909A inFIG. 48 while the distal section921A includes the first andsecond bends911A,913A. Theproximal section919,919A limits migration of the balloon by limiting the overall deflection of the proximal end of the catheter. Thedistal section921,921A preferably has a lower stiffness than theproximal section919,919A so that thedistal section921,921A may conform somewhat to the shape of the aortic arch. Thedistal section921,921A preferably extends between 10 and 20 cm and more preferably between 10 and 15 cm from the proximal portion to thedistal end915A. Theproximal section919,919A preferably extends between 40 and 100 cm, and more preferably between 80-90 cm, from thedistal section921,921A toward the proximal end. The flexible anddistal sections919,919A,921,921A may be coupled together by any conventional method or may be integrally formed with thedistal section921,921A being formed with a smaller, more flexible cross-sectional shape than theproximal portion919,919A or with the proximal section having reinforcing ribbon, wires and the like. The first andsecond portions905,907 also preferably include a frictional coating or surface to further enhance anchoring.
• Referring again toFIG. 47, yet another method of anchoring an occluding member in the ascending aorta is shown. Ananchor923, which is preferably a perfusion catheter, is introduced into the patient and advanced into the brachiocephalic artery. Theanchor923 is coupled to the cardiopulmonary bypass system (seeFIG. 1) for delivering oxygenated blood to the brachiocephalic artery during cardiopulmonary bypass. Theanchor923 advantageously limits migration of the occludingmember901 and ensures oxygenated blood reaches the brachiocephalic artery. Thus, the occludingmember901 ofFIG. 47 is anchored against downstream migration by engagement between thesecond portion907 and the radially inner portion RI of the aortic arch and the occludingmember901 is anchored against upstream migration by theanchor923. The dotted line position of the occludingmember901 illustratesbrachiocephalic anchor923 blocking upstream migration of the occludingmember901. Although it is preferred to provide aseparate anchor923, the brachiocephalic anchor may be coupled to the balloon catheter and deployed therefrom. Furthermore, although it is preferred to use theanchor923 to prevent migration of the occludingmember901, the brachiocephalic anchor may simply be a thin shaft which resists migration of the occluding member while permitting an adequate flow of oxygenated blood into the brachiocephalic artery.
• The methods and devices described herein provide methods and apparatus for anchoring an occluding member and a specific application of the present invention is developed with respect to a system for partitioning a patient's heart and coronary arteries from the remainder of the arterial system. While the above is a description of the invention, various alternatives, modifications and equivalents may be used. For example, the balloon ofFIGS. 37-41 may have any other shape so long as the low friction portions are at radially outward positions relative to the high friction portions, the pressure monitor and pressure sensors may be used with any type of balloon or occluding member, and thecatheter903,903A may have any shape so long as predetermined portions are provided for engaging the radially inner and outer walls of the aortic lumen. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.

Claims (49)

1. A method of anchoring a balloon catheter in a patient, comprising the steps of:

positioning the balloon in the patient's body passageway with the balloon in the collapsed shape so that the radially outward extremes contact the body passageway; and advancing the balloon in the patient to a position to be occluded with the balloon in the collapsed shape;

inflating the balloon after the advancing step so that the high friction portion contacts the patient's body passageway for anchoring the balloon in the patient's body passageway.

2. The method ofclaim 1, wherein:

the positioning step is carried out by inserting the balloon into the patient's arterial system; and

the inflating step is carried out with the balloon being positioned in the patient's ascending aorta.

3. The method ofclaim 1, wherein:

the providing step is carried out with the balloon catheter having a first lumen and an opening at the distal end fluidly coupled to the first lumen, the opening being configured for delivery of a fluid into a patient,

4. The method ofclaim 3, further comprising the step of:

introducing cardioplegic fluid into the patient through the first lumen.

5. The method ofclaim 1, wherein:

the providing step is carried out with the balloon catheter having at least three arms extending radially outward from the shaft.

6. The method ofclaim 1, wherein:

the providing step is carried out with the high friction portion having a plurality of ribs.

7. The method ofclaim 1, wherein:

the providing step is carried out with the shaft having a substantially straight portion and a hooked portion connected to the substantially straight portion.

8. A balloon catheter for occluding a body passageway in a patient, comprising:

a shaft; and

a balloon mounted to the shaft, the balloon having an expanded shape and a collapsed shape, the expanded shape being configured to occlude a body passageway in a patient, the balloon including an outer surface having at least two high friction portions and a low friction portion, the low friction portion having a lower coefficient of friction than the high friction portions relative to the patient's body passageway, the balloon having at least three radially extending arms when in the collapsed shape, each of the at least two low friction portions being positioned at radially outward extremes of adjacent radially extending arms, the high friction portion being exposed and being positioned between two of the radially outward extremes of the radially extending arms when the balloon is in the collapsed shape, the high friction portion being everted when the balloon moves from the collapsed shape to the expanded shape.

9. The balloon catheter ofclaim 8, wherein:

the balloon is configured and sized to occlude the patient's ascending aorta.

10. The balloon catheter ofclaim 8, wherein:

the shaft includes a first lumen and an opening at the distal end fluidly coupled to the first lumen, the opening being configured for delivery of a fluid into a patient.

11. The balloon catheter ofclaim 8, further comprising:

a source of cardioplegic fluid fluidly coupled to the first lumen.

12. The balloon catheter ofclaim 8, wherein:

the high friction portion includes a plurality of ribs.

13. The balloon catheter ofclaim 8, wherein:

the shaft has a substantially straight portion and a hooked portion connected to the substantially straight portion.

14. A method for positioning a balloon in a passageway and occluding the passageway, comprising the steps of:

providing a catheter having a shaft and a balloon mounted thereto, the balloon having a collapsed shape and an expanded shape;

inserting the catheter into a body passageway of a patient with the balloon in the collapsed shape;

positioning the catheter in a portion of the body passageway for occluding the portion of the body passageway; inflating the balloon with a fluid;

monitoring a rate of pressure increase in the balloon with respect to a fluid volume in the balloon; and

adding an amount of fluid after the rate of pressure increase in the balloon exceeds a predetermined threshold.

15. The method ofclaim 14, wherein:

the positioning step is carried out by positioning the balloon in the patient's ascending aorta.

16. The method ofclaim 14, wherein:

the providing step is carried out with the catheter having a lumen fluidly coupled to the balloon, the catheter also having a pressure sensor and a pressure sensing alarm, the pressure sensing alarm indicating when the rate of pressure increase in the balloon exceeds the predetermined threshold.

17. The method ofclaim 14, wherein:

the adding step is carried out with the amount of fluid being a predetermined volume of fluid.

18. The method ofclaim 14, wherein:

the adding step is carried out by adding the amount of fluid to increase the pressure in the balloon a predetermined amount.

19. A device for pressurizing a balloon catheter, comprising:

a catheter having a shaft and a balloon mounted thereto, the balloon having a collapsed shape and an expanded shape, the collapsed shape being configured for advancement within a patient the catheter having a first lumen fluidly coupled to the balloon for inflating the balloon;

a fluid source coupled to the first lumen for inflating the balloon;

a pressure sensor configured to measure a pressure in an interior of the balloon; and

a pressure monitor coupled to the pressure sensor, the pressure monitor determining when a rate of pressure increase in the balloon with respect to an increase in fluid volume in the balloon exceeds a predetermined threshold.

20. The device ofclaim 19, further comprising:

means for adding a predetermined amount of fluid after the pressure monitor detects the rate of pressure increase exceeds the predetermined threshold.

21. The device ofclaim 19, further comprising:

means for increasing the pressure in the balloon a predetermined amount after the pressure monitor detects the rate of pressure increase exceeds the predetermined threshold.

22. A method of anchoring an occluding member in a patient, comprising the steps of:

inserting a catheter having an occluding member mounted thereto, the occluding member having a collapsed shape and an expanded shape;

positioning the occluding member in a body passageway in the patient; expanding the occluding member to the expanded shape after the positioning step to thereby occlude the body passageway;

monitoring a pressure exerted on the occluding member on a distal side and a proximal side of the occluding member; and

determining a difference between the pressure on the distal and proximal sides of the occluding member.

23. The method ofclaim 22, further comprising the step of:

adjusting a pressure on at least one of the distal and proximal sides of the occluding member.

24. The method ofclaim 22, wherein:

the adjusting step is carried out by adjusting a pressure on the distal side of the occluding member.

25. The method ofclaim 22, wherein:

the inserting step is carried out with the occluding member being a balloon.

26. The method ofclaim 22, wherein:

the inserting step is carried out with the body passageway being an ascending aorta.

27. A catheter for occluding an ascending aorta in a patient, comprising:

a shaft having a distal end and a proximal end;

an occluding member mounted to the shaft, the occluding member having an expanded shape sized to occlude the patient's ascending aorta; a first pressure sensor positioned between the distal end and the occluding member for measuring a pressure on a first side of the occluding member; and

a second pressure sensor positioned between the proximal end and the occluding for measuring a pressure on a second side of the occluding member.

28. The catheter ofclaim 27, further comprising:

a pressure monitor coupled to the first and second pressure sensors, the pressure monitor determining a pressure difference between the first and second pressure sensors.

29. The catheter ofclaim 28, further comprising:

an alarm coupled to the pressure monitor for indicating when a pressure difference sensed by the first and second pressure sensors exceeds a predetermined threshold.

30. The catheter ofclaim 27, wherein:

the occluding member is a balloon; and

the shaft includes a first lumen, a second lumen and an opening at the distal end of the shaft fluidly coupled to the first lumen, the second lumen being fluidly coupled to the balloon for inflating the balloon.

31. The catheter ofclaim 30, further comprising:

means for adjusting the pressure on at least one of the first and second sides of the balloon when a pressure difference sensed by the first and second pressure sensors exceeds a predetermined threshold, the pressure adjusting means reducing the pressure difference to a value below the predetermined threshold.

32. The catheter ofclaim 31, wherein:

the pressure adjusting means is coupled to the first lumen for adjusting a fluid pressure exerted by fluid delivered into the ascending aorta through the first lumen.

33. A method of anchoring an occluding member in an ascending aorta of a patient, comprising the steps of:

inserting a catheter into a patient, the catheter including a shaft having an occluding member at a distal end, the occluding member having a collapsed shape and an expanded shape;

positioning the catheter in the patient's ascending aorta;

expanding the occluding member to the expanded shape after the positioning step to thereby occlude the ascending aorta; and

displacing the shaft of the catheter a first amount after the expanding step so that a predetermined portion of the catheter contacts the patient's aortic lumen for anchoring the occluding member in the ascending aorta.

34. The method ofclaim 33, wherein:

the displacing step is carried out by withdrawing an amount of the catheter from the patient so that the predetermined portion of the catheter engages a radially inner portion of the patient's ascending aorta.

35. The method ofclaim 33, further comprising the step of:

displacing the catheter a second amount in a direction opposite to the first amount so that a second predetermined portion of the shaft engages a radially outer wall of the patient's ascending aorta.

36. The method ofclaim 33, further comprising the step of:

inserting the shaft through a delivery cannula, the delivery cannula having a shaft engaging mechanism and a shaft displacing mechanism; the displacing step being performed with the shaft displacing mechanism of the delivery cannula.

37. A catheter having an expandable member for occluding an ascending aorta in a patient, comprising:

a shaft having a longitudinal axis, a distal end, a proximal end, a first lumen and an opening at the distal end in fluid communication with the opening, the opening being configured for delivery of a fluid into the patient's ascending aorta;

an expandable member mounted near the distal end of the shaft, the expandable member having an expanded shape and a collapsed shape, the expanded shape being configured to occlude the patient's ascending aorta; and

a delivery cannula, the shaft being movably coupled to the delivery cannula for movement in a direction parallel to the longitudinal axis in an inward direction and an outward direction;

the shaft having a first portion configured to contact the radially inner wall of the aortic lumen when the shaft is slidably displaced in the outward direction.

38. The catheter ofclaim 37, further comprising:

a shaft displacing mechanism coupled to the delivery cannula, the shaft displacing mechanism being configured to displace the shaft a predetermined amount in the outward direction so that the first portion engages the radially inner wall of the aortic lumen.

39. The catheter ofclaim 37, wherein:

the shaft includes a second portion configured to contact a radially outer wall of the aortic lumen when the shaft is slidably displaced in the inward direction.

40. The catheter ofclaim 39, wherein:

the shaft includes a third portion configured to contact the radially outer wall of the aortic lumen when the shaft is slidably displaced in the inward direction, the second portion being positioned between the first and second portions.

41. The catheter ofclaim 37, wherein:

the delivery cannula includes a lumen for introducing a fluid into the patient.

42. The catheter ofclaim 37, wherein:

the shaft includes a first bend and a second bend, the first portion being positioned between the first and second bends.

43. A method of anchoring an occluding member in a patient comprising the steps of:

inserting a catheter into a patient, the catheter having an occluding member mounted thereto;

positioning the occluding member at a desired location;

expanding the occluding member to occlude the desired location; and clamping a portion of the passageway adjacent the desired location to prevent migration of the occluding member.

44. The method ofclaim 43, wherein:

the inserting step is carried out with the occluding member being a balloon.

45. The method ofclaim 43, wherein:

the clamping step is carried out by clamping the body passageway around the balloon thereby trapping the balloon.

46. The method ofclaim 43, wherein:

the inserting step is carried out with the balloon having an indentation; and

the clamping step is carried out with the clamp being positioned around the indentation.

47. A method of anchoring an occluding member in a patient's ascending aorta comprising the steps of:

inserting an occluding member in the ascending aorta between the coronary ostia and the brachiocephalic artery;

expanding the occluding member in the patient after the inserting step;

positioning an anchor in the brachiocephalic artery, the anchor having a proximal end extending into the aorta, the anchor preventing migration of the occluding member beyond the brachiocephalic artery.

48. The method ofclaim 47, wherein:

the positioning step is carried out with the anchor being a perfusion catheter configured to deliver oxygenated blood to the brachiocephalic artery.

49. The method ofclaim 47, wherein:

the anchor is separate from the catheter.

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