US20020151970A1 - Methods and devices for implanting cardiac valves - Google Patents

Abstract

The valve implantation system has a valve displacer for displacing and holding the native valve leaflets open in a first aspect of the invention. A replacement valve may be attached to the valve displacer before or after introduction and may be positioned independent of the valve displacer. In another aspect of the invention, the valve displacer and valve are in a collapsed condition during introduction and are expanded to deploy the valve displacer and valve. The valve is a tissue valve mounted to an expandable support structure. The support structure may have protrusions for engaging the valve displacer or barbs for anchoring the valve displacer to the heart or blood vessel. A temporary valve mechanism may be used to provide temporary valve functions during and after deployment of the valve displacer.

Description

BACKGROUND OF THE INVENTION
• The present invention is directed to methods and devices for implanting replacement cardiac valves. Replacement cardiac valves are implanted when the patient's native valve exhibits abnormal anatomy and function due to congential or acquired valve disease. Congenital abnormalities can be tolerated for years only to develop into life-threatening problems later. Acquired valve disease may result from various causes such as rheumatic fever, degenerative disorders of the valve tissue, and bacterial or fungal infections.[0001]
• Valve dysfunction can be classified as either stenosis, in which the valve does not open properly, or insufficiency, in which the valve does not close properly. Stenosis and insufficiency can occur at the same time and both abnormalities increase the workload on the heart in pumping blood through the body. The ability of the heart to function with the increased workload is a major factor in determining whether the valve should be replaced.[0002]
• When the valve must be replaced using conventional methods, the patient must undergo an invasive, traumatic surgical procedure. The patient's chest is opened with a median sternotomy or major thoracotomy to provide direct access to the heart through the large opening in the chest. The heart is then stopped and the patient is placed on cardiopulmonary bypass using catheters and cannulae inserted directly into the heart and great vessels. The heart, or a great vessel leading to the heart, is then cut open to access and remove the malfunctioning valve. After removing the valve, the replacement valve is then sewn into place. After the new valve has been implanted, the chest is then closed and the patient is weaned off cardiopulmonary bypass support.[0003]
• The conventional open-chest surgery described above is problematic in that it is highly invasive, traumatic and requires a lengthy recovery time. These drawbacks to conventional open-chest surgery prevent some patients from undergoing a valve implantation procedure even though a new cardiac valve is needed.[0004]
• U.S. Pat. No. 5,370,685. U.S. Pat. No. 5,411,552 and U.S. Pat. No. 5,718,725, which are hereby incorporated by reference, describe devices and methods for implanting a new cardiac valve without requiring a median sternotomy or major thoracotomy. Such devices and methods reduce the pain, trauma and recovery time as compared to conventional open-chest surgery.[0005]
• An object of the present invention is to provide additional devices and methods which reduce the trauma associated with conventional open-chest methods and devices for implanting cardiac valves.[0006]
SUMMARY OF THE INVENTION
• In accordance with the object of the invention, a system and method for implanting a cardiac valve is provided which does not require a median sternotomy or major thoracotomy. The devices and methods of the present invention are preferably carried out by passing the valve through a blood vessel, preferably the femoral artery, so that the median sternotomy or major thoracotomy is not required. Alternatively, the systems of the present invention also permit introduction of the valve through a small incision between the patient's ribs without cutting the ribs or sternum.[0007]
• In a first aspect of the invention, a valve displacer is used to hold the native valve leaflets open so that the native valve does not need to be removed. The valve displacer is preferably introduced into the patient in a collapsed condition and expanded to displace and hold the leaflets open. The valve displacer may either be expanded with an expansion mechanism, such as a balloon, or may be self-expanding. In a preferred embodiment, the valve displacer has a first end, a second end and a central section between the first and second ends. The first and second ends are preferably flared outwardly to form a circumferential recess around the central portion. The native leaflets are trapped within the recess when the valve displacer is deployed.[0008]
• In another aspect of the invention, the valve is also introduced into the patient in a collapsed condition and expanded within the patient. The valve may either be expanded with an expansion mechanism, such as a balloon, or may be self-expanding. The cardiac valve may be coupled to the valve displacer or may be positioned independent from the valve displacer while still substantially performing the functions of the native valve. For instance, a replacement aortic valve may be positioned in the ascending or descending aorta to substantially perform the functions of the native aortic valve.[0009]
• The cardiac valve is preferably delivered separate from the valve displacer but may also be integrated with the valve displacer during introduction and deployment. In a preferred embodiment, the valve has protrusions which engage openings in the valve displacer. In another embodiment, the valve has sharp elements or barbs which either pierce the native valve tissue or engage the sides of the openings in the valve displacer.[0010]
• In yet another aspect of the present invention, the valve and valve displacer are preferably introduced into the patient with a catheter system. In a preferred system, the valve displacer is mounted to a first catheter and the valve is mounted to a second catheter which passes through and is slidably coupled to the first catheter. Alternatively, the valve displacer and valve may be mounted to a single catheter. The term catheter as used herein refers to any catheter, trocar or similar device for introducing medical devices into a patient.[0011]
• In still another aspect of the present invention, the valve delivery catheter has a temporary valve mechanism which provides temporary valve functions after deployment of the valve displacer. The temporary valve mechanism prevents regurgitation while the native valve is held open and before deployment of the replacement cardiac valve. The temporary valve mechanism is preferably a balloon which is inflated and deflated as necessary to permit downstream flow and prevent retrograde flow. Although it is preferred to implant the cardiac valve while the patient's heart is beating, the devices and methods of the present invention may also be used with the patient's heart stopped and the patient supported by a bypass system.[0012]
• These and other advantages and aspects of the invention will become evident from the following description of the preferred embodiments and claims.[0013]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1A shows a system for implanting a cardiac valve.[0014]
• FIG. 1B shows the system of FIG. 1A introduced through a femoral vein.[0015]
• FIG. 2 shows the system of FIG. 1 with a sheath retracted to expose the cardiac valve, a valve displacer and a temporary valve mechanism.[0016]
• FIG. 3 shows the valve displacer positioned between the native valve leaflets prior to expansion.[0017]
• FIG. 4 shows the valve displacer expanded by a first expansion mechanism.[0018]
• FIG. 5 shows the valve expanded by a second expansion mechanism into engagement with the valve displacer.[0019]
• FIG. 6 shows the valve displacer and valve implanted in the native valve position.[0020]
• FIG. 7 shows the valve displacer in the collapsed position.[0021]
• FIG. 8 shows the valve displacer in the expanded position.[0022]
• FIG. 9 shows the valve and valve displacer in the expanded position.[0023]
• FIG. 10 shows the valve in a collapsed condition.[0024]
• FIG. 11 is a plan view of the valve showing the leaflets.[0025]
• FIG. 12 is a cross-sectional view of the catheter along line A-A of FIG. 5.[0026]
• FIG. 13 shows another system for implanting another cardiac valve.[0027]
• FIG. 14 is a partial cut-away view of the catheter of FIG. 13 with the valve contained in a chamber.[0028]
• FIG. 15 is a cross-sectional view of the catheter along line B-B of FIG. 13.[0029]
• FIG. 16 shows another system for implanting a cardiac valve.[0030]
• FIG. 17 shows the system of FIG. 16 with a distal portion of the valve displacer extending from the catheter.[0031]
• FIG. 18 shows the valve displacer fully deployed to hold the native leaflets open.[0032]
• FIG. 19 shows the valve partially expanded with the catheter manipulated so that the valve engages the valve displacer.[0033]
• FIG. 20 shows the valve fully deployed and the catheter removed.[0034]
• FIG. 21 is a partial cut-away view of the catheter of FIGS.[0035]16-19.
• FIG. 22 is a cross-sectional view of the catheter along line C-C of FIG. 16.[0036]
• FIG. 23 shows another system for implanting a cardiac valve with the valve displacer positioned between the native leaflets.[0037]
• FIG. 24 shows the valve displacer expanded.[0038]
• FIG. 25 shows the valve partially deployed within the valve displacer.[0039]
• FIG. 26 shows the valve fully deployed within the valve displacer.[0040]
• FIG. 27 shows the valve displacer holding the native leaflets open with the valve deployed in the ascending aorta.[0041]
• FIG. 28 shows the valve displacer holding the native leaflets open with the valve deployed in the descending aorta.[0042]
• FIG. 29 shows the cardiac valve of FIGS.[0043]23-28 in the collapsed condition.
• FIG. 30 shows the cardiac valve of FIGS.[0044]23-28 in the expanded condition.
• FIG. 31 shows another system for delivering a cardiac valve with the delivery catheter passing through a trocar in the ascending aorta.[0045]
• FIG. 32 shows an expansion mechanism expanding the valve displacer and the valve.[0046]
• FIG. 33 shows sutures being pulled to invert the valve.[0047]
• FIG. 34 shows the valve being stored in a preservative solution.[0048]
• FIG. 35 shows the valve inverted and in the expanded condition.[0049]
• FIG. 36 shows the valve and valve displacer in the collapsed condition before being attached to one another.[0050]
• FIG. 37 shows the valve and valve displacer attached to one another and mounted to the delivery catheter.[0051]
• FIG. 38 shows the valve and the valve displacer in the expanded condition.[0052]
• FIG. 39 shows the catheter passing through the femoral vein, into the right atrium, and through the intraatrial septum into the left atrium to access the mitral valve.[0053]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Referring to FIGS. 1A, 1B and[0054]2asystem for implanting a replacement cardiac valve is shown. The present invention is described in connection with implantation of a replacement aortic valve but is applicable to any other cardiac valve. Thesystem2 includes adelivery catheter4, a cardiac valve6 and avalve displacer8. Aprotective sheath10 covers thedelivery catheter4, cardiac valve6 andvalve displacer8 during introduction to prevent contact between the blood vessel and the cardiac valve6 andvalve displacer8. FIGS. 1A and 1B show thesheath10 extending around the cardiac valve6 andvalve displacer8 and FIG. 2 shows thesheath10 retracted to expose the cardiac valve6 andvalve displacer8.
• The cardiac valve[0055]6 is preferably introduced through a peripheral vessel such as the femoral artery (FIGS. 1A and 2) or femoral vein (FIG. 1B). FIG. 1B shows introduction of thecatheter2 through the femoral vein, into the right atrium, through the intraatrial septum and into the left atrium to access the mitral valve. The peripheral vessel is preferably a femoral vessel but may also be the internal jugular vein, subclavian artery, axillary artery, abdominal aorta, descending aorta or any other suitable blood vessel. As will be explained below, thedelivery catheter4 may be introduced by surgical cutdown or percutaneously using the Seldinger technique. An advantage of passing thecatheter4 through a peripheral vessel is reduced trauma to the patient as compared to the conventional open-chest procedure described above. Although it is preferred to deliver the cardiac valve6 through a peripheral vessel, the cardiac valve6 may also be introduced directly into the ascending aorta through a small incision between ribs. Thesystem2 of the present invention is small enough to deliver between the patient's ribs so that the advantages of the present invention over conventional open-chest surgery are provided even when introducing the catheter through an incision in the chest.
• The[0056]valve displacer8 is expanded within the native valve to hold the native cardiac valve leaflets6 open. An advantage of thesystem2 and method of the present invention is that the native valve does not need to be removed. The replacement cardiac valves described herein may, of course, also be used when removing the native valve rather than using thevalve displacer8. Furthermore, thevalve displacer8 and cardiac valve6 may be integrated into a single structure and delivered together rather than separately. Thus, all features of any valve displacer described herein may also form part of any of the cardiac valves described herein without departing from the scope of the invention.
• The[0057]valve displacer8 is shown in the collapsed condition in FIGS. 3 and 7 and in the expanded condition in FIGS. 4 and 8. When in the collapsed position, thevalve displacer8 forms a number oflongitudinal slots12 which formopenings14 in thevalve displacer8 when in the expanded condition. Thevalve displacer8 is substantially cylindrical in the collapsed condition to facilitate introduction into the patient.
• Referring to FIG. 8, first and second ends[0058]16,18 of thevalve displacer8 flare outwardly to form acircumferential recess24 at acentral section22. The native leaflets are trapped in therecess24 when thevalve displacer8 is deployed. Thefirst end16 has threeextensions20 extending from thecentral section22. Thevalve displacer8 may be made of any suitable material and preferred materials include stainless steel, nitinol, keviar, titanium, nylon and composites thereof. Thevalve displacer8 may also be coated with an antithrombogenic coating. Thevalve displacer8 is preferably formed from a solid hypotube by etching or micromachining, machining from a solid material, or welding wire elements together. Although it is preferred to provide the flared ends16,18, thevalve displacer8 may have any other suitable shape which holds the leaflets open. Thevalve displacer8 may also have afabric cover17 which can trap calcium fragments which might break free from the valve when the valve displacer is deployed. Thecover17 is preferably made of a polyesther knit material, such as dacron, but may be made of any other suitable material.
• The cardiac valve[0059]6 has anexpandable support structure26 which moves from the collapsed position of FIGS. 4 and 10 to the expanded position of FIGS. 5 and 9. Thesupport structure26 is preferably formed with first and secondelongate members28,30 which are wound to formwindings31, preferably about 12-18windings31, around the circumference of the valve6. The first and secondelongate members28,30 are attached to one another atwindings31 which forms threeposts32 extending from thesupport structure26.
• The[0060]support structure26 has aprotrusion34, preferably three, extending outwardly to form an interrupted lip around anend35 of thesupport structure26. Theprotrusions34 engage theopenings14 in thevalve displacer8 as shown in FIG. 9 to secure the cardiac valve6 to thevalve displacer8. Theprotrusions34 are preferably formed by acoil36 wrapped around theloops31 in theelongate member30. As will be described below, thesupport structure26 may also have barbs to secure the cardiac valve6 to thevalve displacer8 or to the blood vessel wall. The cardiac valve6 may also engage thevalve displacer8 with any other suitable connection.
• The[0061]posts32 support avalve portion38 which performs the functions of the patient's malfunctioning native valve. Referring to FIGS. 10 and 11, thevalve portion38 is preferably a stentless tissue valve such as a tri-leaflet39 stentless porcine valve. Thevalve portion38 has a base41 which is secured to thesupport structure26 with sutures (not shown). Thevalve portion38 may be stored separately fromsupport structure26 and attached to thesupport structure26 before the procedure. Although it is preferred to provide a tissue valve for thevalve portion38, thevalve portion38 may also be made of a flexible, synthetic material. For example, thevalve portion38 may be made of polyurethane similar to the valves described in “A Tricuspid Polyurethane Heart Valve as Alternative to Mechanical Prostheses or Bioprostheses.” by Lo et al., Trans Am Society of Artificial Internal Organs, 1988; 34: pgsvalve displacer 839-844, and “Evaluation of Explanted Polyurethane Trileaflet Cardiac Valve Prostheses,” Journal Thoracic Cardiovascular Surgery, 1988; 94: pgs 419-429.
• Referring to FIGS.[0062]2-4, thedelivery catheter4 has atemporary valve mechanism40 which provides temporary valve functions during and/or after deployment of thevalve displacer8. Thetemporary valve mechanism40 ensures proper blood flow regulation when the leaflets are held open by thevalve displacer8 to provide time for accurate positioning and deployment of the valve6. Thetemporary valve mechanism40 is preferably aballoon44 coupled to aninflation mechanism47 controlled by acontrol system42. Thecontrol system42 senses the patient's heartbeat to time balloon inflation and deflation to permit and prevent flow in the same manner as the native valve. Similar systems for synchronizing inflation and deflation of a balloon with the patient's heartbeat are known in balloon pump technology and are described in U.S. Pat. Nos. 5,817,001, 5,413,549 and 5,254,097 which are hereby incorporated by reference. Theballoon44 is preferably inflated with a gas for quick inflation and deflation. Thetemporary valve mechanism40 is preferably theballoon44 but may also be a passive mechanical valve which automatically opens and closes due to blood flow forces.
• The[0063]catheter4 may also include anelongate balloon45 to help pump blood through the patient's body like a blood pump. Theballoon45 is also coupled to aninflation mechanism49 controlled by thecontrol system42 which inflates and deflates theballoon45 to provide pumping assistance to the patient's heart. Balloon pump technology is described in the above-mentioned patents. Theelongate balloon45 may be replaced by any other suitable blood pump, such as a centrifugal pump having an impeller, without departing from the scope of the invention.
• The[0064]temporary valve mechanism40 andballoon45 are, of course, only necessary when implanting the valve with the patient's heart beating. If the patient's heart is stopped and the patient is supported by a bypass system during the valve implantation procedure, thetemporary valve mechanism40 and/orballoon45 may be used after the procedure for emergency valve functions or pumping assistance. Theballoon44 is preferably positioned in the ascending or descending aorta and theballoon45 is preferably positioned in the descending aorta.
• Referring to FIGS.[0065]3-6, thedelivery catheter4 also has first and secondexpandable members46,48 which deploy thevalve displacer8 and cardiac valve6, respectively. Theexpandable members46,48 are preferably balloons50,52 but may also be mechanically actuated devices. Theballoons50,52 are coupled toinflation lumens54,56 through which inflation fluid is delivered from sources ofinflation fluid58,60, respectively. Theballoon50 expands greater at the ends to form the flared ends16,18 of thevalve displacer8.
• The[0066]delivery catheter4 includes afirst catheter62, which carries thevalve displacer8, and asecond catheter64, which carries the cardiac valve6. Referring to FIGS. 2 and 12, thesecond catheter64 has apassageway66 which receives thefirst catheter62. Ahemostasis valve68 permits slidable movement between the first andsecond catheters62,64. Thefirst catheter62 haslumen54 for inflatingballoon50 and thesecond catheter64 haslumen48 for inflatingballoon52. Thesecond catheter64 also has alumen51 for inflatingballoon44 and alumen53 for inflatingballoon45. Thefirst catheter62 also has amain lumen70 which receives aguidewire72.
• The slidable connection between the first and[0067]second catheters62,64 permits introduction of thefirst catheter62 over theguidewire72 with thesecond catheter64 being advanced over thefirst catheter62 after thevalve displacer8 is in the ascending aorta. In this manner, thefirst catheter62 may be advanced more easily over theguidewire72 and through the patient's vasculature, such as around the aortic arch, as compared to a single, multichannel catheter having all features of the first andsecond catheters62,64. The first andsecond catheters62,64 may be wire-reinforced (not shown) catheters constructed in the manner described in Published PCT Application WO 97/32623 entitled “Cannula and Method of Manufacture and Use” which is hereby incorporated by reference.
• A method of implanting a cardiac valve[0068]6 in accordance with the present invention is now described in connection with FIGS.1-6. Although the method is described in connection with the system described above, the method may be practiced with other suitable devices, including the devices and systems described below, without departing from the scope of the invention. Furthermore, the method is described in connection with replacing the aortic valve, however, the method may also be applied to other other cardiac valves such as the mitral, tricuspid and pulmonary valves.
• Before implanting the cardiac valve[0069]6, it may be desirable to perform valvuloplasty to break up pathologic adhesions between the native valve leaflets. Breaking up adhesions ensures that thevalve displacer8 expands fully to provide a large blood flow path. Valvuloplasty is preferably performed with a balloon which is inflated to open the leaflets and break the adhesions. The native cardiac valve and annulus are also sized to determine the propersize valve displacer8 and cardiac valve6. Sizing may be carried out using fluoroscopy, intravascular ultrasound or with any other suitable device during or after the valvuloplasty. Size parameters to consider include the cross-sectional profile through the valve, the length and size of the valve leaflets and position of the coronary ostia.
• The[0070]delivery catheter4 is preferably introduced into the patient by surgical cutdown in the femoral artery but may also be introduced percutaneously using the Seldinger technique. As mentioned above, thedelivery catheter4 may also be introduced into any other suitable vessel or through a small incision in the chest. The first andsecond catheters62,64 are advanced into the artery through the cutdown a short distance. Theguidewire72 is then advanced ahead of the first andsecond catheters62,64 up the descending aorta, around the aortic arch, into the ascending aorta and across the aortic valve. Thefirst catheter62 is then advanced over theguidewire72 to the ascending aorta with thesheath10 covering thefirst catheter62 to prevent contact between thevalve displacer8 and the blood vessel or native valve. Thesecond catheter64 is then advanced over thefirst catheter62 to position the cardiac valve6 in the ascending aorta. Thesheath10 also prevents contact between the cardiac valve6 and vessel wall when advancing thesecond catheter64. Thesheath10 is then retracted as shown in FIG. 2 to expose thevalve displacer8 and the cardiac valve6.
• The[0071]valve displacer8 is then introduced between the valve leaflets as shown in FIG. 3 and theballoon50 is inflated to expand the valve displacer as shown in FIG. 4. Thevalve displacer8 holds the native valve leaflets open so that the native valve does not have to be removed. When thevalve displacer8 has been deployed, thetemporary valve mechanism40 provides temporary valve functions by inflating and deflating theballoon44 at appropriate times to permit and block flow in the same manner as the native valve. Theballoon45 may also be inflated and deflated to provide pumping assistance to the patient's heart during the procedure. Although the above-described method is performed with the patient's heart beating, the procedure may also be performed on a stopped heart with the patient supported by a bypass system.
• The[0072]second catheter64 is then advanced until the valve6 is positioned adjacent thevalve displacer8. Although FIG. 5 shows thefirst catheter62 extending into the left ventricle, thefirst catheter62 may also be designed to be withdrawn into thepassageway66 of thesecond catheter64 so that thefirst catheter62 does not extend beyond thesecond catheter64. Theballoon52 is then partially inflated so that the distal end of the valve6 having theprotrusions34 expands. Thesecond catheter64 is then manipulated until theprotrusions34 engage theopenings14 in thevalve displacer8. Theballoon52 is then inflated further to expand the rest of thesupport structure26. Thecatheters62,64 are then removed leaving the cardiac valve6 in place.
• Referring to FIGS. 13 and 14, another[0073]system2A for implanting acardiac valve6A is shown wherein the same or similar reference numbers refer to the same or similar structures. Thecardiac valve6A is similar to the cardiac valve6 described above, however, thecardiac valve6A is self-expanding and, therefore, does not require an independent expansion mechanism. Thesupport structure26A is made of a resilient material to naturally bias thesupport structure26A to the expanded position. Thesupport structure26A may be made of any suitable material and preferred materials are stainless steel or shape-memory alloys such as nitinol.Delivery catheter4A has theexpandable member46, which is preferably theballoon50, for expanding thevalve displacer8.
• The[0074]cardiac valve6A is contained within anouter wall74 of thedelivery catheter4A. Thecardiac valve6A is advanced out of achamber76 in thedelivery catheter4A by advancing arod78 having apusher element80 attached thereto. Thepusher element80 engages theposts82 on thecardiac valve6A to move thecardiac valve6A out of thechamber76. Therod78 has threadedconnections80,82 with atip84 and thepusher element80 to facilitate assembling thedelivery catheter4A and loading thecardiac valve6A in thechamber76. Therod78 has aguidewire lumen86 for receiving theguidewire72. Referring to the cross-sectional view of FIG. 15, thecatheter4A has afirst lumen88 coupled to theballoon50, asecond lumen90 coupled to theballoon44 and a third lumen91 coupled to theballoon45. The second andthird lumens88,90 are coupled to theinflation mechanisms47,29 which are controlled by thecontrol system42 described in connection with FIGS. 1 and 2. Thesystem2A preferably includes thesheath10 which prevents contact between the blood vessel and thevalve displacer8 when thecatheter4A is advanced through the blood vessel.
• The[0075]cardiac valve6A is implanted in substantially the same manner as the cardiac valve6 and the discussion of implantation of the cardiac valve6 is also applicable here. Thedelivery catheter4A may be introduced in any manner described herein and FIG. 13 shows thecatheter4A extending through the femoral artery with thevalve displacer8 positioned between the valve leaflets prior to expansion. Thevalve displacer8 is expanded in the manner explained above to hold the leaflets open. After thevalve displacer8 has been expanded, thecatheter4A is retraced a predetermined amount so that theprotrusions34 are exposed outside the distal end of thecatheter4A. Thecatheter4A may then be manipulated as necessary so that theprotrusions34 engage theopenings14 in thevalve displacer8. Thevalve6A preferably remains coupled to thecatheter4A while theprotrusions34 are exposed for manipulation of thevalve6A until thevalve6A engages thevalve displacer8. After thevalve6A has engaged thevalve displacer8, therod78 is then advanced far enough to completely release thecardiac valve6A.
• Referring to FIGS.[0076]16-22, anothersystem4B for implanting thecardiac valve4A is shown wherein the same or similar reference numbers refer to the same or similar structure. The system has the self-expandingcardiac valve4A described above. Thevalve displacer8B is similar to thevalve displacer8 described above, however, thevalve displacer8B is also self-expanding and, therefore, does not require an independent expansion mechanism. Thevalve displacer8B is made of a resilient material to naturally bias thevalve displacer8B to the expanded position. Thevalve displacer8B may be made of any suitable material and preferred materials are stainless steel and shape-memory alloys such as nitinol.
• The valve displacer SB and[0077]cardiac valve6A are contained within anouter wall74 of thedelivery catheter4B as shown in FIG. 21. Thevalve displacer8B andcardiac valve4A are advanced out of achamber76B in thedelivery catheter4B by advancing arod78B having first and second pusher elements80B.81B attached thereto. Therod78B has threadedconnections79B.82B, and83B with thetip84 and the first and second pusher elements80B.81B to facilitate assemblingcatheter4B and loading thevalve displacer8B andcardiac valve6A in thechamber76B. Therod78B has theguidewire lumen86 for receiving the guidewire72 (FIG. 14). Referring to FIG. 16 and the cross-sectional view of FIG. 22, thecatheter4B has alumen90 coupled to theballoon44 which serves as thetemporary valve mechanism40 and alumen93 which is coupled to theballoon45. Thelumen90 andlumen93 are coupled to theinflation mechanisms47,29 which are controlled by the control system42 (FIGS. 1A, 1B, and2).
• Another method of implanting a cardiac valve is now described with reference to FIGS.[0078]16-20 wherein the same or similar reference numbers refer to the same or similar struture. The method describes use of thedelivery catheter4B andcardiac valve6A, however, the method may be practiced using other suitable structures. Thedelivery catheter4B is introduced in any manner described above and is preferably introduced through the femoral artery. Theguidewire72 is advanced ahead of thecatheter4B into the ascending aorta and thedelivery catheter4B is advanced over theguidewire72. Thedelivery catheter4B is then advanced between the valve leaflets. A distal end of thevalve displacer8B is then advanced out of thechamber76 and thecatheter4B is retracted until thevalve displacer8 contacts the valve opening. Thecatheter4B is then retracted while therod78B is maintained in the same position so that thevalve displacer8B emerges from thechamber76B as shown in FIG. 18. Thecatheter4B is then advanced a predetermined amount and the rod is advanced to force a distal end of thevalve6A from thechamber76B. Thecatheter4B is then moved as necessary so that theprotrusions34 engage theopenings14 in thevalve displacer8 as shown in FIG. 19. Thecatheter4B is then withdrawn further so that thesupport structure26A expands to the fully deployed position of FIG. 20. Thecatheter4B is then removed leaving thecardiac valve6A as shown in FIG. 20 During the procedure described above, thetemporary valve mechanism40 provides temporary valve functions while theballoon45 provides pumping assistance as described above.
• Referring to FIGS.[0079]23-30, anothersystem2C for implanting acardiac valve6C is shown. Thesystem2C includes thevalve displacer8 anddelivery catheter4 described above. Thedelivery catheter4 has theballoon50 for inflating thevalve displacer8, theballoon52 for inflating acardiac valve6C, thetemporary valve mechanism40 and theballoon45. Thecardiac valve6C is similar to thecardiac valves6,6A except that thecardiac valve6C hasbarbs100 which extend outwardly from thecardiac valve6C in the expanded condition of FIG. 30. Thebarbs100 secure thecardiac valve6C to thevalve displacer8 or directly to the vessel wall. Thecardiac valve6C hasdepressions102 so that thebarbs100 are recessed from anouter surface104 of thecardiac valve6C when in the collapsed position of FIG. 29. Thedepressions102 prevent thebarbs100 from interfering with smooth retraction of thesheath10. When thecardiac valve6C is expanded, thedepressions102 andbarbs100 rotate and move outwardly to engage thevalve displacer8 or vessel wall.
• The[0080]system2C is introduced into the patient in any manner described above and FIG. 23 shows thedelivery catheter4 passing through the femoral artery. Thevalve displacer8 is deployed in the manner described above wherein thevalve displacer8 is introduced into the valve leaflets and expanded with theballoon50 to hold the native leaflets open as shown in FIG. 24. Thedelivery catheter4 may then be advanced so that thecardiac valve6C is expanded in thevalve displacer8 with thebarbs100 passing into theopenings14 to secure thecardiac valve6C to thevalve displacer8 as shown in FIGS. 25 and 26. Thebarbs100 may be long enough to pierce and anchor in the native valve leaflets or may be designed to merely pass into and engage the sides of theopenings14.
• The term “cardiac valve” as used herein refers to a valve which substantially replaces the function of the patient's malfunctioning cardiac valve. The valve may be positioned in the native valve position or may be positioned in a different location while still substantially performing the functions of the native valve. For example, a replacement aortic valve may be positioned superior to the coronary ostia, in the aortic arch or in the descending aorta. Such a replacement valve will substantially function like the patient's native aortic valve. Referring to FIGS. 27 and 28 the[0081]cardiac valve6C is deployed in the ascending and descending aorta with thebarbs100 securing thecardiac valve6C directly to the vessel wall.
• Referring to FIGS.[0082]31-38 anothersystem2D for introducing avalve6D is shown wherein similar or the same reference numbers refer to similar or the same structure. Thevalve6D is coupled to avalve displacer8D prior to introduction into the patient. Thevalve6D has anexpandable support structure26D which is movable from the collapsed position of FIGS. 36 and 37 to the expanded position of FIGS.34 and35. Thesupport structure26D hasflexible joints106 which bend to radially collapse thesupport structure26D. Thesupport structure26D hasprotrusions34D which engageholes108 in thevalve displacer8D. Thevalve6D andvalve displacer8D may engage one another in any other suitable manner.
• The[0083]valve6D is inverted before being attached to thevalve displacer8D as shown in FIG. 35. A number ofsutures110, preferably three, are then passed through thevalve6D. Thesutures110 are used to invert the valve after introduction into the patient as will be explained below. Thevalve6D may be any of the valves described herein or any other suitable valve without departing from the scope of the invention. Acircumferential ring111 extends around thesupport structure26D. Thering111 is preferably made of stainless steel or shape-memory alloy such as nitinol and provides circumferential support of the valve against the aortic wall for hemostasis.
• The[0084]valve displacer8D is mounted to a delivery catheter4D having aballoon112 for expanding thevalve displacer8D andvalve6D. Theballoon112 is coupled to a source of inflation fluid114 (FIG. 31) for inflating theballoon112. The catheter4D passes through atrocar116 having ahemostasis valve117. Thesutures110 and the catheter4D pass through the hemostasis valve which permits slidable movements of thesutures110 and catheter4D.
• The[0085]valve6D is preferably stored in a preservative solution until just before the procedure as shown in FIG. 34. The valve is then inverted as shown in FIG. 35 and thesutures110 are passed through thevalve6D. Thevalve6D is then attached to thevalve displacer8D as shown in FIG. 37 and mounted to the delivery catheter4D.
• The[0086]valve6D may be delivered in any manner described above and is preferably introduced through an incision in the patient's chest. Referring to FIGS. 31 and 32, thetrocar116 is introduced into the ascending aorta through purse-string sutures (not shown). Thetrocar116 may have a chamber (not shown) in which thevalve6D is positioned when thetrocar116 is introduced into the ascending aorta. The sheath10 (see FIGS. 1A, 1B and2) described above may also be used to prevent contact between the valve and trocar and between the valve and the aortic wall. Thevalve6D is preferably introduced with the patient's heart beating but may also be implanted with the patient's heart stopped and the patient supported by a bypass system. Althoughsystem2D does not show theballoons40 and45, it is understood that theballoons40,45 may also be used withsystem2D without departing from the scope of the invention.
• After introduction of the[0087]trocar116, thevalve6D is advanced until thevalve6D is between the native valve leaflets. Theballoon112 is then inflated to expand thevalve6D andvalve displacer8D. The catheter4D is then removed and thesutures110 are pulled to invert thevalve6D as shown in FIG. 33. An end of eachsuture110 is then pulled to remove thesutures110. Thetrocar116 and catheter4D are then removed leaving thevalve6D (FIG. 38).
• Although the foregoing invention has been described by way of illustration and example of preferred embodiments for purposes of clarity and understanding, changes and modifications to the preferred embodiments may be incorporated without departing from the scope of the invention. For example, the native valve may be removed rather than held open with the valve displacer, the replacement cardiac valve may be a completely synthetic or mechanical valve, and the expansion mechanism may be a mechanical mechanism rather than a balloon.[0088]

Claims (29)

What is claimed is:

1. A method of implanting a cardiac valve, comprising the steps of:

introducing a valve and a valve displacer into a patient, the valve and valve displacer being movable from collapsed positions to expanded positions, the valve and valve displacer being introduced into the patient in the collapsed position;

positioning the valve displacer between valve leaflets of a native cardiac valve;

expanding the valve displacer to the expanded position after the positioning step thereby displacing and holding the valve leaflets in an open position; and

securing the valve at a desired location in the patient.

2. The method ofclaim 1, wherein:

the securing step is carried out with the replacement valve being secured to the valve displacer.

3 The method ofclaim 2, wherein:

the securing step is carried out with the valve interlocking with the valve displacer.

4. The method ofclaim 2, wherein:

the securing step is carried out with the valve having sharp elements which penetrate the native valve.

5. The method ofclaim 1, wherein:

the introducing step is carried out with the valve having a support structure and a valve portion, the support structure being expandable from a collapsed position to an expanded position, the introducing step being carried out with the support structure being in the collapsed position.

6. The method ofclaim 1, wherein:

the securing step is carried out with the desired valve location being spaced apart from the valve displacer.

7. The method ofclaim 6, wherein:

the securing step is carried out with the desired location of the valve being between the coronary ostia and the brachiocephalic artery.

8. The method ofclaim 1, wherein:

the introducing step is carried out with the valve displacer being mounted to a catheter.

9. The method ofclaim 8, further comprising the step of:

enclosing the valve displacer in a flexible sheath during the introducing step; and

uncovering the valve displacer before the expanding step.

10. The method ofclaim 8, wherein:

the introducing step is carried out with the catheter passing through a penetration in the aortic arch.

11. The method ofclaim 8, wherein:

the introducing step is carried out through the femoral artery.

12. The method ofclaim 1, wherein:

the introducing step is carried out with the valve being mounted on a catheter.

13. The method ofclaim 8, wherein:

the introducing step is carried out with the catheter having an expandable member, the valve displacer being mounted to the expandable member.

14. The method ofclaim 12, wherein:

the introducing step is carried out with the catheter having a valve mechanism.

15. The method ofclaim 12, wherein:

the introducing step is carried out with the catheter having a balloon, the balloon being coupled to a control mechanism for inflating and deflating the balloon to provide pumping assistance to the patient's heart.

16. The method ofclaim 1, wherein:

the introducing step is carried out with the valve displacer being mounted on a catheter.

17. The method ofclaim 16, wherein:

the introducing step is carried out with the catheter having an expandable member, the valve displacer being mounted to the expandable member.

18. The method ofclaim 14, wherein:

the introducing step is carried out the valve displacer having an end which flares outwardly when the valve displacer is in the expanded position.

19. The method ofclaim 1, wherein:

the introducing step is carried out with the valve displacer having a circumferential recess formed between the first end and a second end.

20. The method ofclaim 1, wherein:

the securing step is carried out before the introducing step so that the valve and valve displacment device are introduced together.

21. The method ofclaim 20, further comprising the step of:

inverting the valve after the introducing step.

22. The method ofclaim 1, wherein:

the valve introducing step is carried out with the valve having an expandable support structure, the expandable support structure having at least three posts extending from the expandable support structure.

23. A device for maintaining a patient's native valve leaflets open, comprising:

a first end;

a second end; and

a central section extending between the first and second ends;

the first and second ends being flared outwardly from the central section so that the central section forms a recess for receiving the native valve leaflets, the first end, second end and central section forming a structure which is movable from a collapsed condition to an expanded condition.

24. The device ofclaim 23, wherein:

the first end, second end and central section are integrally formed.

25. The device ofclaim 23, wherein:

the structure is substantially cylindrical in the collapsed condition, the first and second ends flaring outwardly from the central section when the structure is in expanded condition.

26. The device ofclaim 23, wherein:

the structure has a circumferential recess for retaining the native valve leaflets, the circumferential recess extending around the central section.

27. The device ofclaim 23, further comprising:

a valve portion attached to at least one of the first end, second end and central section, the valve portion permitting blood flow therethrough in one direction and preventing flow in the other direction.

28. The device ofclaim 27, wherein:

the valve portion is a tissue valve.

29. The device ofclaim 27, wherein:

the valve portion lockingly engages at least one of the first end, second end and central section.

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