Leaflet suturing to commissure points for prosthetic heart valve

A collapsible prosthetic heart valve includes a collapsible and expandable stent and a collapsible and expandable valve assembly. The stent has a proximal end and a distal end. A plurality of commissure points is disposed on the stent. The valve assembly is disposed within the stent and includes a plurality of leaflets. Each leaflet has a free edge. An end portion of the free edge of each leaflet is folded and sutured to a corresponding one of the plurality of the commissure points.

BACKGROUND OF THE INVENTION

The present invention relates to heart valve replacement and, in particular, to collapsible prosthetic heart valves. More particularly, the present invention relates to collapsible prosthetic heart valves.

Prosthetic heart valves that are collapsible to a relatively small circumferential size can be delivered into a patient less invasively than valves that are not collapsible. For example, a collapsible valve may be delivered into a patient via a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for a more invasive procedure such as full open-chest, open-heart surgery.

Collapsible prosthetic heart valves typically take the form of a valve assembly or structure mounted on a stent. There are many types of stents that may be used. However, two types of stents on which the valve structures are ordinarily mounted include: a self-expanding stent and a balloon-expandable stent. To place such valves into a delivery apparatus and ultimately into a patient, the valve must first be collapsed or crimped to reduce its circumferential size.

When a collapsed prosthetic valve has reached the desired implantation site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and expanded to the full operating size. For balloon-expandable stents, this generally involves releasing the entire valve, assuring its proper location, and then expanding a balloon positioned within the stent. For self-expanding stents, on the other hand, the stent automatically expands as the sheath covering the valve is withdrawn.

The leaflets in a collapsible prosthetic heart valve, over their useful life, must open and close millions of times. This repeated movement can cause various stresses on the leaflets and, in particular, where they are secured to the rest of the valve. Improper or inadequate attachment can lead to tearing of pulling away from the stent and failure of the valve. And valve failure, in the circulatory system, can have significant consequences for the patient. Accordingly, there remains a need for improved methods of producing heart valves and securing valve leaflets in collapsible prosthetic heart valves.

SUMMARY OF THE INVENTION

The present disclosure relates to prosthetic heart valves. In one embodiment, the prosthetic heart valve includes a stent and a valve assembly. The stent has a collapsed condition and an expanded condition and includes a plurality of commissure points disposed thereon. The valve assembly is secured to the stent and includes a plurality of leaflets. Each leaflet includes a free edge. An end portion of the free edge of the leaflet is folded and sutured to a corresponding one of the plurality of the commissure points.

In an embodiment of the present invention, the end portions of the free edges of first and second adjacent leaflets are sutured to one another. In another embodiment, the prosthetic heart valve further includes a reinforcement layer disposed between the folded end portions of the free edge of the leaflet.

In certain embodiments of the present invention, the folded end portion of the free edge of the leaflet is generally parallel to the immediately adjacent portions of the leaflet and/or generally perpendicular to the commissure point. In other embodiments, the folded end portion of the free edge of the leaflet is generally perpendicular to the immediately adjacent portions of the leaflet and/or generally parallel to the commissure point.

The free end of the folded end portion of the free edge of the leaflet may extend beyond the suture toward the immediately adjacent portion of the leaflet. In yet another embodiment, the end portion of the free edge of the leaflet may be rolled into a generally spiral configuration. In still another embodiment, the folded end portion of the free edge of the leaflet may include two or more folds.

The end portion of the free edge of the leaflet may wrap at least partially around the commissure point. A web overlying the end portion of the free edge of the leaflet may substantially wrap around the commissure point and may be sutured to be end portion and the commissure point.

Moreover, the leaflet may include “tabs” or ends which are attached to the commissure points or a portion of the attached edge may be sutured thereto.

According to yet another embodiment of the present invention, a prosthetic heart valve includes a stent and a valve assembly disposed within the stent. Each of the stent and the valve assembly has a collapsed condition and an expanded condition. The stent has a proximal end and a distal end. A plurality of commissure points is disposed on the stent. The valve assembly includes a plurality of leaflets, each of which has a free edge. An end portion of the free edge of the leaflet is folded and sutured to a corresponding one of the commissure points. The end portion is folded in a configuration selected from the group consisting of a U-shaped pleat, an S-shaped pleat, a generally spiral roll and a U-shaped pleat enveloped by an external web.

DETAILED DESCRIPTION

As used herein, the term “proximal,” when used in connection with a prosthetic heart valve, refers to the end of the heart valve closest to the heart when the heart valve is implanted in a patient, whereas the term “distal,” when used in connection with a prosthetic heart valve, refers to the end of the heart valve farthest from the heart when the heart valve is implanted in a patient.

As seen inFIG. 1, a collapsible prosthetic heart valve100typically includes a stent or frame102supporting a valve assembly104. Examples of collapsible prosthetic heart valves are described in International Patent Application Publication No. WO/2009/042196; U.S. Pat. Nos. 7,018,406; 7,329,278, United States Patent Application Publication Nos. 2005/0113910 and 2009/0030511, the disclosures of all of which are hereby incorporated herein by reference.

The prosthetic heart valve100is designed to replace the function of a native aortic valve of a patient. As discussed in detail below, the prosthetic heart valve has an expanded condition and a collapsed condition. Although the invention is described herein as applied to a prosthetic heart valve for replacing a native aortic valve, the invention is not so limited, and may be applied to prosthetic valves for replacing other types of cardiac valves.

The prosthetic heart valve100includes a stent or frame102, which may be wholly or partly formed of any biocompatible material, such as metals, synthetic polymers, or biopolymers capable of functioning as a stent. Suitable biopolymers include, but are not limited to, elastin, and mixtures or composites thereof. Suitable metals include, but are not limited to, cobalt, titanium, nickel, chromium, stainless steel, and alloys thereof, including nitinol. Suitable synthetic polymers for use as a stent include, but are not limited to, thermoplastics, such as polyolefins, polyesters, polyamides, polysulfones, acrylics, polyacrylonitriles, polyetheretherketone (PEEK), and polyaramides. The stent102may have an annulus section110and an aortic section (not shown). Each of the annulus section110and the aortic section of the stent102includes a plurality of cells112connected to one another around the stent. The annulus section110and the aortic section of the stent102may include one or more annular rows of cells112connected to one another. For instance, the annulus section110may have two annular rows of cells112. When the prosthetic heart valve100is in the expanded condition, each cell112may be substantially diamond shaped. Regardless of its shape, each cell112is formed by a plurality of struts114. For example, a cell112may be formed by four struts114.

The stent102may include commissure points116connecting at least two cells112in the longitudinal direction of the stent102. The commissure points116may include eyelets for facilitating the suturing of a valve assembly104to the stent102.

The prosthetic heart valve100also includes a valve assembly104attached inside the annulus section110of the stent102. United States Patent Application Publication Nos. 2008/0228264, filed Mar. 12, 2007; 2008/0147179, filed Dec. 19, 2007; 2005/0113910, filed Jul. 10, 2004; and 2009/0030511, filed Jan. 29, 2009, the entire disclosures of all of which are hereby incorporated herein by reference, describe suitable valve assemblies. The valve assembly104may be wholly or partly formed of any suitable biological material or polymer materials in the forms of sheets, non-woven and woven fabrics and the like. Examples of biological materials suitable for the valve assembly104include, but are not limited to, porcine or bovine pericardial tissue. Examples of polymers suitable for the valve assembly104include, but are not limited to, polyurethane and polyester.

The valve assembly104may include a cuff106disposed on the lumenal surface of annulus section110, on the ablumenal surface of annulus section110, or on both surfaces, and the cuff may cover all or part of either or both of the lumenal and ablumenal surfaces of the annulus section.FIG. 1shows cuff106disposed on the lumenal surface of annulus section110so as to cover part of the annulus section while leaving another part thereof uncovered. The valve assembly104may further include a plurality of leaflets108which collectively function as a one-way valve. A first edge122of each leaflet108may be attached to the stent102by any suitable attachment means, such as suturing, stapling, adhesives or the like. A second or free edge124of each leaflet108may coapt with the corresponding free edges of the other leaflets, thereby enabling the leaflets to function collectively as a one-way valve.

Irrespective of the attachment means employed, the leaflets108may be attached to the stent102along at least some struts114of the stent102to enhance the structural integrity of the valve assembly104. As a consequence of this attachment, the struts114help support the leaflets108of the valve assembly104and may therefore reduce the strain in the leaflets.

As shown inFIG. 1, at least one leaflet108may be attached to the stent102so that its first edge122is disposed substantially along specific struts114a,114b,114c,114d,114eand114flocated in the annulus section110of the stent. That is, the edge122is positioned in substantial alignment with struts114a,114b,114c,114d,114e, and114f. Also as shown, the edge122can be roughly parallel to the edge of the cuff106. However, of course, the cuff106need not be cut to follow the slope or pattern of the struts. Struts114a,114b, and114cmay be connected to one another in substantially end-to-end fashion diagonally along three cells112, beginning with an end of the strut114aconnected to a commissure point116and ending with an end of strut114cconnected to an end of strut114d. Struts114cand114dare part of the same cell112and may collectively define a substantially right angle between them. Struts114d,114e, and114fmay be connected to one another in substantially end-to-end fashion diagonally along three cells112, beginning with an end of the strut114fconnected to a commissure point116and ending with the connection between an end of strut114cand an end of strut114d.

As discussed above, the leaflets108may be attached directly to and supported by the struts114a,114b,114c,114d,114e, and114f, such as by suturing. In such event, the cuff106may perform little or no supportive function for the leaflets108, and the thickness of the cuff106may, therefore, be reduced. Reducing the thickness of the cuff106results in a decrease in the volume of the valve assembly104in the collapsed condition. This decreased volume is desirable as it enables the prosthetic heart valve100to be implanted in a patient using a delivery device that is smaller than conventional delivery devices. In addition, since the material forming the stent114is stronger than the material forming the cuff106, the stent may perform the supportive function for the leaflets108better than the cuff.

The volume of the valve assembly104may be further reduced by having the cuff106cover only a portion of the surface of annulus section110. With continued reference toFIG. 3, the first or proximal end118of the cuff106may substantially follow the contour of the first or proximal end119of the stent102. As such, the proximal end of the cuff106may have a generally sinusoidal or zigzag shape. This eliminates any free edge of the cuff106, which otherwise might extend directly between the cusps of the cells112at the proximal end119of the stent102, and enables the entire length of the proximal end118of the cuff106to be secured to the stent102. The second or distal end120of the cuff106, on the other hand, may be disposed substantially along at least some struts114, but not necessarily the struts in a single annular row of cells112.

More particularly, the distal end120of the cuff106may follow the stent struts114up to the commissure points116, such that the cuff106covers all of the cells112in the bottom annular row113of cells112and in a second annular row115of cells located between the commissure points and the proximal end119of the stent102, but covers a lesser area of cells in the annular regions between the commissure points. In other words, the distal end120of the cuff106may be disposed substantially along struts114a,114b,114e,114f,114gand114h, as shown inFIG. 1. Strut114gmay be connected at one end to strut114h, and at the other end to the intersection of struts114band114c. Strut114hmay be connected at one end to strut114g, and at the other end to the intersection of struts114dand114e. Struts114c,114d,114g, and114hcollectively form a single cell112.

As a result of the foregoing configuration, all of the cells112in the bottom annular row113of cells112may be entirely covered by the cuff106. The cuff106may also entirely cover those cells112in the second annular row115that are located directly below the commissure points116. All of the other cells112in the stent102may be open or not covered by the cuff106. Hence, there may be no cells112which are only partially covered by the cuff106.

Since the edges of the valve leaflets108extend up to the second annular row115of cells112only in the regions of the commissure points116, there is little to no likelihood of leakage in the area of the cells between the commissure points in the second annular row of cells, and therefore no need for the cuff106to cover this area. This reduction in the area of the cuff106, both at the proximal end118and at the distal end120thereof, reduces the amount of material in the valve assembly104, thereby enabling the prosthetic valve100to achieve a smaller cross-section in the collapsed condition.

With reference toFIG. 2, a prosthetic heart valve300according to another embodiment of the present invention includes a stent or frame302, which may be similar to stent102. The stent302may include an aortic section340and an annulus section310. Each of the aortic section340and the annulus section310may include a plurality of cells312connected to one another in one or more annular rows. The cells312of the aortic section340may be larger than the cells of the annulus section310. Each cell312is formed by a plurality of struts314. For example, each cell312may be formed by four struts314and may be substantially diamond-shaped when the stent302is in an expanded condition. The stent302may further include one or more commissure points316for facilitating suturing of a valve assembly304to the stent. Each commissure point316may interconnect two cells312in the same annular row and two cells in different annular rows.

The valve assembly304may be attached inside the stent302, and may include a cuff306and a plurality of leaflets308which collectively function as a one-way valve. The cuff306may be located on the inside surface of the stent302, on the outside surface of the stent, or on both the inside surface and the outside surface. Each leaflet308includes an edge322attached to the stent302and a second free edge324. An upper portion328of the edge322may be attached to the stent302so as to be disposed substantially along the path of certain struts314that lead to the commissure points316. For example, an upper portion328of the edge322of at least one leaflet308may be attached to, and disposed substantially along, struts314aand314b, and an upper portion328of the edge322of an adjacent leaflet308may be attached to, and disposed substantially along, struts314cand314d. As such, struts314a,314b,314c, and314dhelp support these adjacent leaflets308. The upper portions328of the edges322of adjacent leaflets308may be attached to the commissure point316and struts314a,314b,314c, and314dusing sutures350. Struts314band314cmay each have one end attached to a commissure point316and each may be part of the same cell312.

Alternatively, struts314band314cmay be attached directly to one another. Struts314aand314bmay be connected in an end-to-end fashion, and may be part of different cells312that are adjacent to one another. Similarly, struts314cand314dmay be connected in an end-to-end fashion, and may be part of different cells312that are adjacent to one another.

With reference toFIG. 3, a collapsible prosthetic heart valve400according to an embodiment of the present invention includes a stent402, which may be similar to stent102. The stent402has collapsed and expanded conditions and includes a plurality of cells412connected to one another in annular rows around the stent402. Each cell412is formed by a plurality of struts414and may be substantially diamond shaped when the stent402is in the expanded condition. For example, one cell412may be formed by four interconnected struts414.

The stent402may further include one or more commissure points416that interconnect two adjacent cells412located in one annular row and two other cells412located in the next adjacent rows above and below the one row. The commissure points416may facilitate the suturing of a valve assembly404to the stent402.

The valve assembly404may include a cuff406attached to the interior and/or exterior of the stent402. In addition to the cuff406, the valve assembly404includes a plurality of leaflets408attached to the stent402and collectively defining a one-way valve. Each leaflet408includes a first edge422attached to the stent402and a second free edge424. At least one leaflet408may be attached to the stent402so that the upper portions428of its edge422are substantially disposed along the path of certain struts414.

As shown inFIG. 3, one upper portion428of the edge422of one leaflet408may be connected to a commissure point416and may be disposed along and connected to a strut414bspaced from the commissure point. A section A of the upper portion428of the edge422may follow a substantially direct path between the commissure point416and an end of stent strut414b. Similarly, one upper portion428of the edge422of another leaflet408may be connected to the commissure point416and may be disposed along and connected to a strut414dspaced from the commissure point. A section A of the upper portion428of the edge422of this second leaflet408may follow a substantially direct path between the commissure point416and an end of stent strut414d. The edges422of the leaflets408may be connected to the commissure point416and to the struts414band414dusing sutures.

In operation, any of the embodiments of the prosthetic heart valve described above may be used to replace a native heart valve, such as the aortic valve. The prosthetic heart valve may be delivered to the desired site (e.g., near a native valve annulus) using any suitable delivery device known in the art. During delivery, the prosthetic heart valve is disposed inside the delivery device in the collapsed condition. The delivery device may be introduced into a patient using the transfemoral, transapical or transseptal approach. Once the delivery device has reached the target site, the user may deploy any of the prosthetic heart valves described above. Upon deployment, the prosthetic heart valve expands into secure engagement within the native valve annulus. When the prosthetic heart valve is properly positioned inside the heart, it works as a one-way valve, allowing blood to flow in one direction and preventing blood from flowing in the opposite direction.

In each of the prosthetic heart valve embodiments described above, the valve assembly preferably is spaced from the distal or aortic end of the stent by a distance that enables deployment of the heart valve by an amount sufficient for the valve leaflets of the prosthetic valve to operate as intended, while the distal end of the stent remains captured by the delivery device. More particularly, the annulus end of the prosthetic heart valve may be deployed first while the aortic end of the prosthetic heart valve remains at least partially covered by the distal sheath of the delivery device. The annulus portion of the prosthetic heart valve may be deployed so that the entirety of the valve leaflets, up to and including the commissures, is deployed and fully operational. By deploying the prosthetic heart valve in this manner, the user can determine whether the valve leaflets are properly positioned relative to the native valve annulus, and whether the valve is functioning properly.

If the user determines that the positioning and operation of the valve are acceptable, the remainder of the valve may be deployed. However, if it is determined that the leaflet position is improper or that the valve is not functioning properly, the user may resheath the valve and either reposition it for redeployment, or remove it entirely from the patient. This can be particularly important in very high risk patients who would typically be recipients of these types of valves, because of the nature of their condition and the impact that may have on the shape and/or condition of the native valve and valve annulus. Of course, the prosthetic heart valve of the present invention can be delivered by deploying the aortic or distal end first as well.

Anatomical irregularities at the implantation site can create issues with respect to the proper functioning and wear of the prosthetic heart valve. Another aspect of the invention is the achievement of a better functioning valve in the various shapes, such as elliptical, round, irregular, etc., that the valve may assume upon implantation and use. This may depend, in some instances, not only on leaflet positioning, commissure positioning, and valve geometry, as previously described, but also can relate to the manner in which the leaflets are attached to the valve assembly, the stent, and in particular, the commissure attachment points. As the stent is deformed by implantation and use, if leaflet positioning and geometry are not correct, undesirable load forces at the leaflet edges, particularly at the commissure attachment points, can be created. This can lead to tearing of the leaflets and/or cuff and eventually valve failure.

Some arrangements that are intended to minimize valve failure and promote better valve function are illustrated inFIGS. 4A-4I.FIGS. 4A-4Ishow various arrangements for attaching the leaflets to the commissure points116in order to promote better and longer valve function. Which particular arrangement is used may depend, inter alfa, on the type of valve material used, the thickness of the stent, the dimensions of the commissure points, the type, thickness and placement of the cuff, if any, the overall shape of the valve and valve assembly, and the like. Note that in the various illustrations which represent the end views, as seen from the distal end of the stent along the longitudinal axis of the stent toward the proximal end of the stent, of a commissure point and the attachment of the leaflets thereto (in which the dashed lines represent suture lines), the cuff is not illustrated for purposes of clarity.

Referring toFIG. 4A, portions of two adjacent leaflets108aand108bare illustrated. Note that the leaflets108aand108bare illustrated as generally parallel to each other only for the sake of simplicity. In actuality, the adjacent leaflets108a,108bwill generally diverge from one another as they extend away from the commissure point116. In the illustrated embodiment, an end portion722aof leaflet108ais folded in a generally “U-shaped” pleat737a. Likewise, an end portion722bof leaflet108bis folded in a generally “U-shaped” pleat737b. The folded end portions722a,722bmay be generally parallel to the immediate adjacent portions735a,735b, respectively, of the leaflets108a,108band generally perpendicular to the commissure point116. The folded end portions722a,722bmay be sutured to one another by one or more sutures710(a pair of sutures illustrated). In addition, end portion722amay be sutured to commissure point116via one or more sutures720aand end portion722bmay be sutured to commissure point116via one or more sutures720b(a single suture illustrated). Since the sutures710a,710bpass through the U-shaped pleats737a,737b, respectively, the stresses induced in the leaflet108a,108bdue to the sutures at the sites of the sutures may be more widely distributed, thereby minimizing the likelihood of a tear in the leaflets due to suturing.

FIG. 4Billustrates the suturing of the leaflets to the commissure point116according to another embodiment of the invention. Each of the end portions722a,722bof the respective leaflets108a,108bis folded in a generally “U-shaped” pleat737a,737b, respectively, as in the embodiment ofFIG. 4A, and the U-shaped pleats737a,737bare then bent outwardly so as to lie substantially perpendicular to the immediate adjacent portions735a,735bof the leaflets108a,108band generally parallel to the commissure point116. The U-shaped pleat737amay be sutured to the commissure point116via one or more sutures730a. Similarly, the U-shaped pleat737bmay be sutured to the commissure point116via one or more sutures730b. In variants hereof, less than or more than two sutures may be employed to suture each folded end portion722a,722bto the commissure point116. Since sutures730a,730bpass through the U-shaped pleats737a,737b, respectively, the stresses induced in the leaflets108a,108bat the sites of the sutures may be more widely distributed, thereby minimizing the likelihood of a tear in the leaflets due to suturing.

FIG. 4Cillustrates a variant of the embodiment ofFIG. 4B. In the embodiment ofFIG. 4C, the end portions722a,722bhave much larger unsutured free edges724a,724b, respectively, which extend toward the immediate adjacent portions735a,735bof the leaflets108a,108b, respectively, and then curl back toward the U-shaped pleats737a,737b, respectively. This configuration reduces the possibility of tearing the free edges724a,724bof end portions722a,722bdue to the stress induced by the suturing.

Referring toFIG. 4D, the embodiment illustrated is generally similar to the embodiments ofFIGS. 4B and 4C. Whereas in the embodiments ofFIGS. 4B and 4C, the end portions722a,722bof the leaflets108a,108bhave a single fold in the form of U-shaped pleats737a,737b, respectively, the end portions722a,722bin the embodiment ofFIG. 4Dinclude multiple folds in a generally compressed “S-shaped” pleat or a Heintz pleat747a,747b, respectively. While two such folds are shown inFIG. 4Dfor the pleats747a,747b, it will be understood that pleats747a,747bmay include more than two such folds. The additional folds in the embodiment ofFIG. 4Dfurther distribute the stresses due to suturing and reduce the likelihood of tearing the leaflets108aand108b.

Now referring toFIG. 4E, leaflets108a,108bare sutured to the commissure point116according to another embodiment of the invention. The end portion722aof leaflet108ais wrapped around one side of commissure point116such that a U-shaped pleat735ais formed, which generally envelopes one side of the commissure point. Likewise, the end portion722bof leaflet108bis wrapped around the other side of commissure point116such that a U-shaped pleat735bis formed, which generally envelopes the other side of the commissure point. Thus, the commissure point116may be enveloped on opposing sides by the end portions722aand722b, respectively. One or more sutures730a(one pair of suture illustrated) attach the end portion722ato the commissure point116, and one or more sutures730b(one pair of suture illustrated) attach the end portion722bto the commissure point116. The suturing sites on the end portions724aand724bare situated further apart due to the presence of the commissure point116, thereby reducing the stress due to suturing in the leaflets108aand108b. Note that this type of arrangement might necessitate some change in how and where the cuff106is attached. It could be attached on the ablumenal surface over the free ends724a,724b. In other configurations, the cuff106could also be split in the proximity of the commissure point116so that either end may be attached over the top of the inner portion of the folds.

The cuff106could also be attached to the lumenal surface but disposed between and under the commissure points and the proximal end of the stent. These types of cuff arrangements may also be used in connection with, for example, the embodiments illustrated inFIGS. 4F and 4G.

FIG. 4Fillustrates an embodiment which generally includes the features of the embodiment illustrated inFIG. 4E. In particular, the end portion722aof the leaflet108ais wrapped around one side of commissure point116such that a U-shaped pleat735ais formed which envelopes one side of the commissure point116. The end portion722bof the leaflet108bis wrapped around the other side of the commissure point such that a U-shaped pleat735bis formed which envelopes the other side of the commissure point116. A tissue or fabric web750is then wrapped around the end portions722a,722band the commissure point116from the outside surface (the bottom as seen inFIG. 4F) so as to cover any gap between the free ends724aand724b. One or more sutures730a,730b(one pair of sutures illustrated for each leaflet108a,108b) may attach the web750and the end portions722a,722bto the commissure point116. In an exemplary configuration, the web750may be formed from any suitable biological material or polymer. Examples of biological materials suitable for the web750include, but are not limited to, porcine or bovine pericardial tissue. Examples of polymers suitable for the web750include, but are not limited to, polyurethane and polyester. The web750provides reinforcement to the end portions722a,722band reduces the stress induced therein due to the suturing.

In yet another embodiment illustrated inFIG. 4G, which is a variation of the embodiment illustrated inFIG. 4F, the end portions722a,722bof the respective leaflets108a,108bgenerally overlie the commissure point116in an L-shaped fold, but do not wrap around the same. A fabric or tissue web751is then wrapped around the commissure point116so as to overlie the end portions722a,722bof the leaflets108a,108b. In an exemplary embodiment, the web751may be formed from the same materials as may be used for forming the web750. One or more sutures730a(one pair of sutures illustrated) may attach the web751and the end portion722ato the commissure point116. Likewise, one or more sutures730b(one pair of sutures illustrated) may attach the web751and the end portion722bto the commissure point116. The web751provides reinforcement to the end portions722a,722band reduces the stress induced therein due to the suturing.

Referring now toFIG. 4H, leaflets108a,108bare sutured to the commissure point116according to yet another embodiment of the invention. The end portions722a,722bof the respective leaflets108a,108bare rolled into a generally spiral configuration757a,757b, respectively. The rolled end portions722a,722bmay be sutured to the commissure point116via one or more sutures730a,730b, respectively. An advantage of the rolled end portions722a,722bis that the stresses caused by the sutures730a,730bare evenly distributed over the end portions722a,722b.

FIG. 4Iillustrates another exemplary embodiment of the invention. Each of the end portions722a,722bof the respective leaflets108a,108bis folded into a generally “U-shaped” pleat737a,737b, respectively. A cuff706is interposed between the U-shaped pleats737a,737band the commissure point116. The free ends724a,724bof the respective end portions722a,722bare attached to respective remainder portions of the leaflets108a,108b. Reinforcement tissue or fabric webs760a,760bare disposed, respectively, between the folds of each of the end portions722a,722b. The webs760a,760bmay be formed from the same biological or polymeric materials as may be used for forming the web750. One or more sutures730aattach the folded end portion722aalong with the web760aand the cuff706to the commissure point116, while one or more sutures730battach the folded end portion722balong with the web760band the cuff706to the commissure point. The webs760a,760breinforce the folded portions722a,722b.

FIG. 5Aschematically illustrates the leaflet108, which may be sutured to the commissure point116of the stent102using any of the configurations described above. Leaflet108has a free edge505and an arcuate edge507attached, for example, to one or more struts114of the stent102as described above. Leaflet108may include a generally rectangular tab510at one end of the free edge505and another generally rectangular tab520at the other end of the free edge505. The tab510may be defined by a substantially straight outside edge511, a substantially straight inside edge512, that is substantially parallel to the edge511, a substantially straight top edge513, and a substantially straight bottom edge514, that is substantially parallel to the top edge513and substantially orthogonal to the edges511and512. The tab510may include a further projection530projecting laterally from the outside edge511. The tab520may be substantially the same the tab510, but may omit the further projection530.

As noted, the leaflet108may be attached to the commissure point116of the stent102using any of the configurations previously described. The following will describe the attachment of the leaflet108to the commissure point116using the configuration ofFIG. 41. The tab510may include an imaginary fold line532, which is generally aligned with the arcuate edge507of the leaflet108, and is substantially parallel to the edges511and512, dividing the tab510into a first portion542and a second portion544. The tab510may be folded along the fold line532to form, for example, the generally “U-shaped” pleat737ashown inFIG. 41.

FIGS. 5B and 5Cillustrate yet another embodiment of the leaflet108and the suturing of the leaflet to the commissure point116. The leaflet108may be generally similar to the leaflet108ofFIG. 5A, except for the differences set forth below. The leaflet108may include a generally rectangular tab610, similar in configuration to the tab510ofFIG. 5A, extending from one end of the free edge505, and a similar generally rectangular tab640extending from the other end of the free edge505. Rather than having a further projection extending from the outside edge as with tab510, however the tab610may optionally have a further projection630extending from the top edge613. A similar further projection650may extend from the top edge of the tab640.

As noted, the leaflet108may be attached to the commissure point116of the stent102using any of the configurations previously described. Yet another configuration for attaching the leaflet108to the commissure point116is shown inFIG. 5C. The tab610may include an imaginary fold line632, which is generally aligned with the arcuate edge507of the leaflet108and one edge of further projection630, and is substantially parallel to the outside edge611and the inside edge612of tab610, dividing the tab610into a first portion642and a second portion644. A generally vertical slit620, as seen inFIG. 5E, is defined in the first portion642of the tab610and is substantially parallel to the edges611and612. The tab610may be folded along the fold line632to form a generally “U-shaped” pleat637which extends across leaflets108a,108b. The slit620accommodates portions of the free edges of the leaflets108a,108b. One or more sutures730aattach the folded second portion644of the leaflet108band the free end722aof the leaflet108ato the commissure point116. One or more sutures730battach the U-shaped pleat637to the commissure point116. Where the tab610includes further projection630, the further projection may be tacked to the stent and then later removed.