Abstract:
Systems and methods for mitral valve repair having a docking station and a valve implant. The docking station is an anchoring device having a helix structure. The valve implant is made of an expandable frame and a valve, and is radially expandable to a diameter that is at least the same as an expanded diameter of the anchoring device. The method of delivering the docking station and valve implant is performed by inserting the components through device delivery catheters.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 14/188,442, filed Feb. 24, 2014, entitled “Cardiac Valve Repair System and Methods of Use,” which names Jacques Seguin as an inventor, and which is a division of U.S. application Ser. No. 12/839,363, filed on Jul. 19, 2010, now U.S. Pat. No. 8,657,872, entitled “Cardiac Valve Repair System and Methods of Use,” which names Jacques Seguin as inventor, both of which are incorporated by reference herein in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This application generally relates to apparatus and methods for performing transcatheter or minimally invasive repair or replacement of a cardiac valve, such as the mitral valve, by anchoring an expandable replacement valve body to the leaflets of an incompetent cardiac valve. 
       BACKGROUND OF THE INVENTION 
       [0003]    In recent years a wide array of replacement cardiac valves have been proposed for treating cardiac valve diseases, such as valve regurgitation or stenosis. The human heart contains four valves that separate the atria from the lungs and ventricles: The tricuspid valve disposed between the right atrium and right ventricle, the pulmonary valve disposed between the right ventricle and the pulmonary artery, the bicuspid (or mitral) valve disposed between the left atrium and the left ventricle, and the aortic valve disposed between the left ventricle and the aorta. Each of these valves has a slightly different anatomy than the others, requiring differently-designed replacement valve solutions. 
         [0004]    For example, whereas U.S. patent application Ser. No. US 2006/0265056 to Nguyen et al. describes a catheter-delivered aortic valve having a self-expanding stent that causes the valve to become anchored to the valve annulus, such a solution may not be feasible for repair of a mitral valve due to the possibility that the self-expanding stent may occlude the left ventricle outflow tract for the adjacent aortic valve. Accordingly, it would be desirable to provide a transcatheter or minimally-invasive cardiac valve repair system that can employ a replacement valve disposed in an expandable stent body, but that avoids potential disadvantages of the prior art. 
         [0005]    In view of the drawbacks attendant upon using expandable stents for some cardiac valve repair procedures, the state-of-the-art for previously-known cardiac repair procedures has been surgical repair or replacement of defective valves. For example, mitral valve repair currently is handled as an open surgical procedure, in which the defective valve leaflets are cut away and a new valve body, employing either natural tissue or synthetic fabric, is sewn to the valve annulus. U.S. Pat. No. 4,490,859 to Black et al. describes such a replacement valve, which comprises a polymer frame mounted on a sewing ring, wherein the frame is covered by an animal tissue or synthetic fabric frame. 
         [0006]    Other previously-known attempts to repair mitral valves using a minimally invasive or catheter-based approach have sought to reduce the time, skill and effort required to attach the replacement valve to the existing valve annulus using barbs or spring-like clips as described, for example, in U.S. Pat. No. 7,101,395 to Tremulis et al. U.S. Pat. No. 6,419,696 to Ortiz et al. describes a mitral valve repair system comprising a double helix structure that may delivered via catheter or a minimally-invasive route so that upper and lower rings of the double helix sandwich the valve leaflets and increase the rigidity of the leaflets, thus reducing regurgitation. That patent further describes that its double helix structure may be used to anchor a valve body having a fixed outer circumference that is delivered via a surgical or minimally-invasive route. Neither of the valve repair systems described in the foregoing patents permits installation of a replacement cardiac valve body using a purely transcatheter delivery route. 
         [0007]    In view of the above-noted drawbacks of previously-known systems, it would be desirable to provide methods and apparatus for delivering a replacement cardiac valve via a transcatheter approach, either transvascularly or via a minimally-invasive approach. 
         [0008]    It also would be desirable to provide a replacement cardiac valve, and methods of using same, that may be deployed with reduced risk of obstructing an outflow tract of an adjacent cardiac valve. 
         [0009]    It further would be desirable to provide a replacement cardiac valve, and methods of using same, wherein the anchor used to fasten an expandable cardiac valve body limits expansion of the cardiac valve body to a predetermined size and shape. 
         [0010]    It still further would be desirable to provide a replacement cardiac valve, and methods of using same, wherein the replacement cardiac valve is configured to firmly anchor the valve body to the pre-existing cardiac valve leaflets, while reducing the risk of perivalvular leakage. 
         [0011]    It also would be desirable to provide a replacement cardiac valve, and methods of using same in which, in some embodiments, an anchor of the replacement cardiac valve reshapes the pre-existing valve annulus to accommodate alternative replacement valve body configurations. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention provides a replacement cardiac valve, and methods of using same, that overcomes the drawbacks of previously-known systems. Exemplary embodiments of the present invention include an anchor comprising a double helix configured to engage the cardiac valve leaflets of a diseased or defective cardiac valve, and replacement valve body disposed in an expandable stent that is disposed within the anchor, such that the anchor limits expansion of the expandable stent portion of the replacement cardiac valve. The expandable stent of the replacement valve body may be self-expanding or mechanically expanded, e.g., using a balloon catheter or catheter-based mandrel. 
         [0013]    In some embodiments the replacement valve body may comprise a metal alloy or polymer frame covered by animal tissue or synthetic fabric that mimics the valve configuration of the valve being replaced. Alternatively, the valve body may comprise any suitable valve structure suitable for transcatheter delivery. 
         [0014]    In accordance with one aspect of the invention, the anchor and replacement valve body may be implanted using a transvascular approach. Implantation of a mitral valve embodiment of the present invention, for example, may be accomplished by passing a catheter through the femoral vein into the right atrium, followed by a transeptal puncture to gain access to the mitral valve from above. Alternatively, a minimally-invasive approach may be used wherein a catheter is inserted through a keyhole opening in the chest and catheter is inserted transapically from below the mitral valve. In either case, the anchor component of the present invention may then be deployed first, after which the replacement valve body may be deployed within anchor. As a further alternative, the replacement valve body may be pre-attached to the anchor such that the device may be implanted in a single step. 
         [0015]    In accordance with another aspect of the present invention, the expandable stent of the replacement valve body may include a feature, e.g., a reduced diameter section, that is configured to engage the anchor component to reduce the potential for movement of the replacement valve body relative to the anchor. In still other embodiments, expansion of the expandable stent against the anchor may secure the anchor into engagement with the cardiac valve leaflets. In vet further embodiments, the double helix of the anchor may expand during deployment from a delivery configuration that facilitates insertion of a lower ring of the double helix into engagement with the ventricular surfaces of the leaflets and a deployed configuration wherein the double helix assumes an ovoid configuration that approximates the natural shape of the cardiac valve annulus. Alternatively, the double helix of the anchor transitions from a small diameter ring to a larger diameter ring, such that the anchor remodels the shape of cardiac valve annulus, e.g., from a substantially ovoid shape to a substantially circular shape. 
         [0016]    Methods of using the replacement cardiac valve system of the present invention also are provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIGS. 1A and 1B  show an exemplary embodiment of a replacement cardiac valve system constructed in accordance with the principles of the present invention, wherein  FIG. 1A  shows a sectional view in the deployed state and  FIG. 1B  shows a side view in the delivery state. 
           [0018]      FIG. 2  depicts illustrative embodiments of catheters for transvascular delivery of the anchor and valve body components of the present invention. 
           [0019]      FIG. 3  is a sectional view of the left ventricular portion of a human heart showing a mitral valve being repaired using the replacement cardiac valve system of the present invention, wherein the delivery catheter for the anchor has been disposed proximate the atrial surface of the mitral valve. 
           [0020]      FIGS. 4A, 4B and 4C  are illustrative views showing deployment of the anchor component of the present invention in contact with the ventricular surface of a mitral valve undergoing repair, 
           [0021]      FIGS. 5A and 5B  are, respectively, a perspective view and side sectional view showing the anchor component of the present invention fully deployed on the leaflets of a mitral valve. 
           [0022]      FIGS. 6A and 6B  depicts the distal end of the replacement valve body delivery catheter shown in  FIG. 2  approaching, and penetrating, respectively, the mitral valve of  FIG. 5  on which the anchor has been deployed. 
           [0023]      FIG. 7  is a side view showing deployment of the replacement valve body from the delivery catheter. 
           [0024]      FIG. 8  is a view from the atrial side of the mitral valve that undergone repair using the cardiac valve replacement system of the present invention. 
           [0025]      FIGS. 9A and 9B  are schematic illustrations of an alternative embodiment of the cardiac replacement valve system of the present invention in which the anchor is pre-attached to expandable stent and replacement valve body. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Referring to  FIGS. 1A and 1B , an illustrative embodiment of a cardiac repair system constructed in accordance with the principles of the present invention is described. Illustratively, the cardiac valve is designed for replacement of a defective mitral valve, although it could be readily adapted for other cardiac valves. Replacement cardiac valve  10  includes animal tissue or synthetic valve body  20  mounted in expandable stent  30 . Anchor  40  comprising a double helix of a metal alloy is shown engaged on the exterior of stent  30 . Replacement cardiac valve  10  has an expanded, deployed state, shown in  FIG. 1A , and a contracted delivery state, shown in  FIG. 1B , such that the device may be disposed within a delivery catheter for transvascular or minimally-invasive surgical delivery. In  FIG. 1B , anchor  40 , which is separately delivered for this embodiment, is omitted. 
         [0027]    For purposes of illustration only, expandable stent  30  comprises a self-expanding stent constructed using woven metal alloy wires or any of a number of cell patterns cut into a metal alloy tube, using any of a number of previously-known stent making techniques. Stent  30  may include waist portion  31  disposed between upper and lower flared cods  32 , which are configured to engage anchor  40 , described below, to reduce or prevent stent  30  from moving relative to anchor  40  once deployed. Stent  30  may comprise a superelastic material, such as a nickel-titanium alloy, that is treated to expand from the contracted delivery state to the expanded deployed state by isothermal or thermal conversion of a martensitic state to an austenitic state of the alloy. Alternatively, expandable stent  30  may comprise non-superelastic metal alloy, such as stainless steel or cobalt-chrome alloy, that may be compressed onto a balloon catheter and then plastically expanded during deployment. Expandable stent  30  may comprise any expandable cell pattern known in the stent art suitable for providing the range of increases in stent diameter and sufficient rigidity to prevent the stent from moving once deployed. 
         [0028]    Valve body  20  illustratively is constructed as described in U.S. Pat. No. 4,490,859 to Black et al., which is incorporated herein by reference, and comprises treated animal tissue, such as porcine, bovine or equine pericardial tissue, or any of a number of synthetic fabrics, such as a polyethylene terephthalate fabric, e.g., DACRON® (a registered trademark of Invista North America S.A.R.L. Corporation), mounted on a collapsible metal alloy or polymer frame. The collapsible frame  21  (shown in dotted line) preferably includes a pair of upstanding posts  22  disposed on opposite sides of the frame to form commissural points  23  for the tissue or synthetic fabric leaflets  24 . As described in the foregoing patent, the tissue or fabric components of the valve body are cut from flat pieces of material, and then sewn or bonded together, and to the pair of upstanding posts and expandable stent, to form a semilunar valve that mimics the functionality of an intact non-diseased mitral valve. Alternatively, valve body  20  may be of any construction suitable to be collapsed to a reduced diameter so as to permit the expandable stent and attached valve body to be delivered via catheter in a contracted delivery state. 
         [0029]    In accordance with one aspect of the present invention, anchor  40  comprises a helix structure having at least two turns and configured such that one turn of the helix is configured to engage the atrial surface of the cardiac valve leaflets while the other contacts the ventricular surface of the leaflets. Preferably, the anchor comprises a superelastic material that is trained to transform from a substantially straight wire, when disposed within a delivery catheter, to a double helix structure when extruded from the delivery catheter and/or heated. An example of thermally-induced transformation is described in U.S. Pat. No. 4,512,338 to Balko et al., while a similar isothermal transition from stress-induced martensite to austenite is described in U.S. Pat. No. 6,306,141 to Jervis. As described below, the helical anchor performs three functions in the context of the present invention. First, the anchor serves to secure the replacement valve to the mitral valve leaflets without contacting the entire circumference, and potentially, without contacting any portion of the existing valve annulus—thereby reducing the risk that the replacement cardiac valve will obstruct the outflow tract of an adjacent cardiac valve. Second, the anchor, when fully deployed, limits expansion of the expandable stent, and thus ensures that the replacement valve body cannot overexpand during deployment. In this manner, the predetermined diameter of the anchor ensures, e.g., that no gaps can form between the leaflets of the replacement valve body caused by overexpansion of the expandable stent. Third, the anchor serves to retain the edges of the cardiac valve beyond the periphery of the anchor in approximation, thus reducing the risk of perivalvular leaks arising around the replacement cardiac valve. 
         [0030]    Referring now to  FIG. 2 , an exemplary embodiment of a two-piece delivery system for the replacement cardiac valve of the present invention is described. Anchor delivery catheter  50  comprises a suitable length of tubing having distal end  51 , proximal end  52 , an internal lumen extending therebetween, handle portion  53 , and push rod  54  disposed in the internal lumen. As described below in detail with respect to the method of implanting the replacement cardiac valve of the present invention, helical anchor  40  may be straightened and inserted into the lumen of catheter  50  so that its proximal end abut against a distal end of push rod  54 . The proximal end of the straightened anchor  40  may be engaged with the distal end of push rod  54 , e.g., by gripping jaws such as depicted in FIG. 6B of U.S. Pat. No. 6,419,696 to Ortiz et al., or may include male and female threaded ends that interengage. 
         [0031]    In the context of a mitral valve repair system, distal end  51  of catheter  50  may be configured, for example, to be routed transvascularly through an opening in the patient&#39;s femoral vein, through the right atrium and an atrial transeptal puncture into the left atrium. Once so positioned, pushrod  54  may be advanced to extrude the anchor from within the lumen of catheter  50  to engage the cardiac valve leaflets, as explained below. Alternatively, distal end  51  of catheter may be brought into engagement with mitral valve via a minimally-invasive surgical approach, in which the catheter is advanced towards the ventricular side of the mitral valve through a transapical opening in the left ventricle. 
         [0032]    Still referring to  FIG. 2 , valve delivery catheter  60  illustratively comprises inner shaft  61  slidably disposed in sheath  62 . Inner shaft  61  includes distal end  63  having recessed portion  64 , bullet-nosed atraumatic end  65 , proximal end  66 , and an optional guide wire lumen extending throughout the length of inner shaft  61  to accept guide wire  67 . Sheath  62  includes distal end  68  and proximal end  69 , and is disposed on inner shaft  61  so that distal end  68  of sheath  62  may be selectively retracted to uncover recess  64  on inner shaft  61 . Catheters  50  and  60  preferably comprises materials conventionally used in catheter designs, and have lengths and profiles suitable for the selected access path, i.e., either transvascular or transapical. Recess  64  is sized to permit expandable stent  30  and valve body  20  to be compressed within, and retained within, the recessed portion for delivery when covered by sheath  62 . Alternatively, for plastically deformable embodiments of expandable stent  30 , recess  64  on inner shaft  61  may be replaced by an expandable balloon configured, as is conventional in the art of balloon-expandable stents, to be inflated to deploy the expandable stent and valve body within the helical anchor. 
         [0033]    Referring to  FIG. 3 , a method of deploying the cardiac replacement valve of present invention is now described in the context of repairing a defective mitral valve. In  FIG. 3 , the left ventricular quadrant of a human heart H is shown having mitral valve MV located within mitral valve annulus MVA. The leaflets of the mitral valve are tethered to the endocardium of the left ventricle LV via the chordae tendineae CT and papillary muscles PM. The outflow tract of the aortic valve AV is disposed immediately adjacent to mitral valve. As discussed above, this anatomical feature of the mitral valve makes anchoring an expandable stent directly to the mitral valve annulus problematic, since it creates a risk that expandable stent will obstruct the outflow tract for the aortic valve. Alternatively, having an expandable stent expanded into direct engagement with the mitral valve annulus may disrupt or remodel the aortic valve annulus, causing mismatch of the leaflets of that valve and possibly aortic valve regurgitation. 
         [0034]    In  FIG. 3 , anchor delivery catheter  50  is shown approaching the mitral valve with a portion of helical anchor  40  extending from the distal end of the catheter. In accordance with one aspect of the present invention, helical anchor  40  is inserted through the opening between the mitral valve leaflets so that, when the helical anchor expands, the portion of the anchor passing between the leaflets preferably settles into one of two opposite commissural regions between the leaflets. 
         [0035]    Referring now to  FIGS. 4A through 4C , as shown in  FIG. 4A , anchor  40  continues to be extruded from anchor delivery catheter  50  in contact with the ventricular side of mitral valve MV, the anchor forms a substantially circular helical turn  41 . Helical turn  41  expands until it contacts the anterior and posterior edges of the mitral valve annulus, as depicted in  FIG. 4B . As shown in  FIGS. 5A and 5B , once lower helical turn  41  is delivered, catheter  50  may be rotated, e.g., by rotating the handle  53  of anchor delivery catheter  50  while observing deployment of helical anchor  40  under fluoroscopic guidance, so that upper helical turn  42  is disposed on the atrial surface of the leaflets in registration with lower helical turn  41 . Catheter  50  then is withdrawn, leaving the helical anchor disposed with lower helical turn  41  and upper helical turn  42  sandwiching the leaflets of the mitral valve therebetween. 
         [0036]    Next, wire guide  67  is routed through the mitral valve leaflets and, as depicted in  FIG. 6A , valve delivery catheter  60  is advanced along the guide wire until bullet-nosed end cap  65  passes through the leaflets. As distal end  63  of catheter  60  passes through the leaflets, free ends 
         [0037]    FE of the leaflets deflect downward as depicted in  FIG. 6B . As will be understood, only the nearer leaflet along view line  5 B- 5 B is visible in  FIG. 6B ; the free ends FE of both leaflets would be visible along a view line at a 90-degree angle from view line  5 B- 5 B along the circumference of the mitral valve annulus. Free ends FE of the leaflets will be trapped between the expandable stent and the inner circumference of lower helical turn  41  when the expandable stent and valve body are deployed within the helical anchor. Alternatively, the portions of the mitral valve leaflets that extend within the circumference of the helical anchor may be removed using conventional transcatheter cutting means, e.g., using atherectomy catheter as described in U.S. Pat. No. 6,235,042 to Katzman. Distal end  63  of catheter  60  then is advanced, e.g., by monitoring radiopaque markers (not shown) on inner shaft  61  or sheath  62  under fluoroscopic guidance to confirm that waist  31  of expandable stent  30  is aligned with anchor  40 . 
         [0038]    As depicted in  FIG. 7 , after proper positioning of expandable stent  30  has been confirmed, inner shaft  61  of catheter  60  is held stationary while sheath  62  is retracted proximally to uncover replacement cardiac valve  10 . As sheath  62  is retracted, expandable stent  30  self-expands until it contacts the inner circumference, of helical anchor  40 . In particular, waist  31  of expandable stent  30  contacts the inner circumference of helical turn  42  of anchor  40 , while the lower portion of waist  31  expands until it traps the free ends of the mitral valve leaflets against the inner circumference of lower helical turn  41  of anchor  40 . As described, for example, in U.S. Patent Publication No. US 2006/0265056, valve body  20  is coupled to expandable stent  30  so that it deploys as stent  30  expands. Thus, self-expansion of expandable stem  30  also causes valve body  20  to open to its fully deployed and functional position. Distal end  63  of catheter  60  and guide wire  67  are then withdrawn, completing implantation of the replacement cardiac valve. 
         [0039]    In an alternative embodiment, waist  31  of the expandable stent may be substantially omitted, such that expandable stent comprises upper and lower flared ends that meet at the mid-height of the stent, for example, as depicted in U.S. Pat. No. 6,120,534 to Ruiz. In this case, when the stent expands, it will generate forces on lower helical turn  41  and upper helical turn  42  of anchor  40  that urge the turns towards one another, thereby enhancing the grip of the helical anchor on the mitral valve leaflets. 
         [0040]    In a yet further alternative embodiment, expandable stent  30  may comprise a plastically deformable stent that is expanded to its expanded, deployed state using a balloon catheter or expanding mandrel. Preferably, the balloon should be configured, e.g., using multiple spaced-apart lobes so as to not crush valve body  20  during deployment of the stent. In this case, the expandable stent may have a uniform diameter in the contracted delivery position. During deployment of the expandable stent, the stent will expand to the limits permitted by the inner circumference of the helical anchor, while the unrestrained upper and lower portions of the stent beyond the helical anchor will tend to expand slightly more, thus locking the stent into engagement with the helical anchor, and urging the upper and lower helical turns of the anchor into secure engagement with the mitral valve leaflets. 
         [0041]    In accordance with the principles of the present invention, helical anchor  40  serves several functions: (1) it secures the replacement valve to the mitral valve leaflets without contacting the entire circumference; (2) it limits expansion of the expandable stent, and ensures that the replacement valve body cannot over-expand during deployment; and (3) it retains the free edges of the cardiac valve beyond the periphery of the anchor in approximation, thus reducing the risk of perivalvular leaks. As will be observed from the anatomy of the mitral valve depicted in  FIG. 3 , for example, it may not be possible to expand a self-expanding or balloon-expandable stent into direct contact with the mitral valve annulus since the lower end of the stent body may partially obstruct the outflow tract of the adjacent aortic valve. Instead, by placing the helical anchor of the present invention so that it is supported by the mitral valve leaflets, the present invention ensures that the lower end of the expandable stent and valve body do not interfere with the outflow tract of the left ventricle. In addition, because the helical anchor of the present invention preferably contacts at most only the anterior and posterior portions of the mitral valve annulus, there is reduced risk that the expandable stent of the replacement cardiac valve of the present invention will undesirably remodel the adjacent aortic valve, and thus little risk that repairing the mitral valve will lead to a defect in the adjacent aortic valve. Moreover, because the helical anchor limits expansion of the expandable stent to the predetermined inner diameter of the anchor, it ensures that valve body  20  reproducibly deploys to a predetermined diameter regardless of the patient&#39;s particular, and thus no gaps should form between the leaflets of the replacement valve body caused by overexpansion of the expandable stent. Finally, because the upper and lower helical turns of helical anchor  40  securely engage the free ends of the mitral valve leaflets, the inventive system is expected not to suffer from perivalvular leaks. 
         [0042]    With respect to  FIG. 8 , replacement cardiac valve system  10  is described, as viewed from within the left atrium, after deployment in the mitral valve annulus. Upper helical turn  41  of anchor  40  is visible surrounding expandable stent  30 , with the cells of the upper flared portion  32  overhanging anchor  40 . Valve body  20  is visible within expandable stent  30 , including collapsible frame  21 , posts  22  and synthetic fabric leaflets  24 , the free ends of which coapt to create valve opening  25 . Also shown in  FIG. 8  are free ends FE of the pre-existing valve leaflets, which are secured against one another by anchor  40 , and in some embodiments a compressive force applied by expandable stent  30  as discussed above. As can be further seen in  FIG. 8 , each of the free outer edges of the commissural regions between the pre-existing valve leaflets can extend radially beyond the periphery of the anchor  40 . 
         [0043]    In accordance with one aspect of the present invention, anchor  40  contacts the anterior and posterior edges of the mitral valve annulus, and may remodel the valve annulus to a limited extent to provide the desired cross-sectional area for flow passing through valve body  20 , for example, by increasing the length of the minor axis of the valve white decreasing the length of the major axis of the valve (shown by change from the dotted line  70  to the solid line  71 ). Advantageously, this remodeling effect, if present, is not expected to interfere with the annulus shape of, or approximation of the leaflets of, the adjacent aortic valve. 
         [0044]    As will be appreciated by one of ordinary skill, valve body  20  may comprise flow control mechanisms, such as leaflets, balls, flap valves, duck-billed valves, etc., such as art known in the art, without departing from the spirit of the present invention, so long as such valve configurations can be contracted to a reduced delivery state for transcatheter minimally invasive implantation within anchor  40 . In addition, anchor  40  may comprise, for example, a suitably trained shape memory alloy, that expands to non-circular expanded, deployed shape, such as an ovoid or D-shaped configuration. In this latter case, valve body  20  should be configured so that, when expandable stent  30  is fully deployed within anchor  40 , the valve body expands to a predetermined shape with the required level of coaptation. 
         [0045]    Although the embodiments described above contemplate separately delivering anchor  40  from the assembled replacement valve body  20  and expandable stent using the separate catheters discussed above in  FIG. 2 , all components could be delivered using a single catheter having multiple lumens from which the anchor and remainder of the replacement cardiac valve are delivered. Alternatively, anchor  40  may be attached to the expandable stent and valve body, such that the anchor is first deployed and rotated into position on the valve leaflets, and then the expandable stent and valve body are deployed. 
         [0046]    Referring now to  FIGS. 9A and 9B , replacement cardiac valve  80  of the present invention is described, in which like components of the embodiment of  FIG. 1  and denoted by like-primed numbers. In  FIG. 9A , replacement cardiac valve  80  is schematically shown disposed on delivery catheter  90 , such that expandable stent  30 ′ including the replacement valve body (not visible in  FIG. 9A ) is contracted within recess  91  of inner shaft  92 , Sheath  93  is slidably disposed on inner shaft  92  so that it can be retracted proximally to expose replacement cardiac valve  80 . 
         [0047]    In  FIG. 9A , anchor  40 ′ is wrapped in multiple helical turns around the body of expandable stent  30 ′, and is fastened to expandable stent  30 ′ at fixed end  45 . Sheath  92  retains anchor  40 ′ wound down on the exterior of expandable stent until bullet-nose  93  of delivery catheter is inserted through the leaflets of the cardiac valve to be repaired, in a manner similar to that depicted in  FIG. 6B  above. In addition, one or more lock wires  94  extend from the proximal end to the distal end of catheter  90  to secure expandable stent  30  to inner shaft  91  in a manner similar to that disclosed, for example, in U.S. Pat. No. 5,443,500 to Sigwart. As will be understood by one of ordinary skill, lock wires  94  may be retracted proximally to deploy a self-expanding embodiment of expandable stent  30 ′ as described for the preceding embodiments. Alternatively, if expandable stent  30 ′ is balloon expandable, lock wires  94  may be omitted. 
         [0048]    Once replacement cardiac valve  80  is disposed across the valve to be repaired, as may be determined, e.g., using fluoroscopy, sheath  92  is retracted proximally as shown in  FIG. 9B  to allow anchor  40 ′ to unwind to its deployed shape having at least two helical turns,  41 ′ and  42 ′. Catheter  90  then may be rotated to pass the free end of helical turn  41 ′ between the leaflets until anchor  40 ′ fully engages the atrial and ventricular surfaces of the leaflets to sandwich the leaflets between helical turns  41 ′ and  42 ′ in the manner depicted in  FIG. 58 . Lock wires  94  then are retracted proximally to disengage expandable stent  30 ′, causing the expandable stent and valve body disposed therein to self-expand into engagement with anchor  40 ′. Alternatively, if expandable stent  30 ′ is mechanically expanded, the balloon or mandrel may be actuated to expand stent  30 ′ and the replacement valve body into engagement with helical anchor  40 ′ in a manner similar to that shown in  FIGS. 7 and 8 . 
         [0049]    While various illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the invention. The appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of the invention.