HK1122978A - Prosthetic mitral heart valve having a contoured sewing ring - Google Patents

Description

Prosthetic mitral heart valve with contoured sewing ring

Technical Field

【0001】 The present invention relates generally to implantable prosthetic heart valves for the mitral annulus, and more particularly to a contoured sewing ring for such prosthetic heart valves.

Background

【0002】 Two main types of heart valve replacement or repair are known. One is a mechanical-type heart valve that uses a ball and cage device or rotating mechanism cover supported by an underlying structure to provide unidirectional blood flow, as shown in U.S. patent No.6,143,025 to Stobie et al and U.S. patent No.6,719,970 to brenzel et al, the disclosures of which are expressly incorporated herein by reference. The other is a tissue-type or "bioprosthetic" valve, which has flexible leaflets supported by the base structure and projecting into the blood flow, functions very similar to the natural human heart valve, and mimics its natural flexing action to engage each other and ensure unidirectional blood flow. One example of a flexible leaflet valve is disclosed in U.S. Pat. No.6,585,766 to Huynh et al, the disclosure of which is expressly incorporated herein by reference.

【0003】 In tissue-type valves, an intact xenograft valve (e.g., porcine) or a plurality of xenograft leaflets (e.g., bovine pericardium) typically provide fluid occluding surfaces. Synthetic leaflets have been proposed, and thus the term "flexible leaflet valve" refers to both natural and artificial "tissue-type" valves. Two or more flexible leaflets are mounted in a peripheral support structure that typically includes struts or commissures (comassure) extending in the outflow direction to simulate natural fibrous commissures in the native annulus. The components of the valve are typically assembled with one or more biocompatible fibrous (e.g., dacron) coverings (covering), with a fabric-covered sewing ring provided at the inflow end of the peripheral support structure.

【0004】 In most bioprosthetic valves, a metal or polymer structure provides the base scaffold for the flexible leaflets extending therefrom. One such stent is an elastic "stent frame", sometimes referred to as a "wireform" or "stent", which has a plurality (usually three) large radius tips that support the tip region of the flexible leaflets (i.e., either the whole xenograft valve or the three individual leaflets). The ends of each pair of adjacent cusps converge somewhat asymptotically to form upstanding commissures that terminate in cusps, each extending in opposite directions from the arcuate cusps and having a relatively smaller radius. The stent frame is generally described as a conical tube with commissure tips at the small diameter end. This provides a wavy reference shape to which the fixed edge of each leaflet is attached (by means such as fabric and sutures) like the natural fibrous skeleton in the annulus. Other "stent frame" configurations may exhibit a sheet-like tubular shape, but still define commissures and cusps of the outflow end, as shown in U.S. patent No.5,984,973 to Gerard et al, the disclosure of which is expressly incorporated herein by reference.

【0005】 The most common locations for implanting prosthetic heart valves are the aorta and the mitral valve associated with the left ventricle, where the pressure generated by the left ventricle is higher in both ventricles. The anatomy of the aortic and mitral valves is very different, the former being a tri-leaflet structure, the latter having two distinct leaflets. The aortic annulus (aortic annulus) defines a wavy fibrous structure substantially surrounding a circular ring to support the superior-and-inferior shape of the tip and commissures of the native leaflets. On the other hand, the mitral annulus has a certain fibrous linear anterior aspect (organ aspect) that spans the heart septum from the aortic valve, while the posterior aspect (sterner aspect) defines the majority of the annulus, with less fiber and more muscle. Also, the posterior aspect approximates an ellipse so that the mitral annulus assumes a deformed "D" shape. Moreover, the mitral annulus does not undulate up and down around its periphery as does the aortic annulus, but is generally planar, albeit preceded by a contour (contourr) in which it is generally lower at the fibrous trigones and elevated in the middle to form a saddle. The present invention is directed to prosthetic heart valves, particularly those adapted for implantation at the mitral annulus.

【0006】 The left ventricle LV and its associated valves are illustrated in fig. 1 in a vertical cross-section along the anterior-posterior aspect. The mitral valve MV controls flow between the left atrium LA and the left ventricle LV, while the aortic valve AV functions between the left ventricle LV and the ascending aorta AA. Both the mitral valve and the aortic valve include leaflets that extend into the blood flow path and are supported around their peripheries by respective rings. For purposes of discussion, the mitral annulus of a normal, healthy heart generally lies within a mitral annulus plane MAP, which is defined perpendicular to a mean blood flow direction 20 through the mitral valve MV (see FIG. 1). While a typical mitral annulus may be three-dimensional, the mitral annulus plane MAP will serve as a reference plane that extends through the anterior and posterior aspect of the annulus. Although not shown, papillary muscles (papillary muscles) are attached to the lower portion of the inner wall of the left ventricle LV, and chordae tendineae (chordae tendineae) extend between and connect the papillary muscles and the free edges of the anterior and posterior leaflets.

【0007】 Fig. 2 illustrates the mitral valve from the left atrium as exposed during surgery, while fig. 2A schematically identifies features common in plan view. Average cross-sectional area of human mitral annulus of 5-11cm². The anterior aspect of the mitral annulus forms part of the "heart skeleton" and includes anterolateral ALT and posteromedial PMT fibrous trigones. The mitral valve MV is a mitral valve with posterior leaflet (divided into three cusps P)₁，P₂，P₃) The posterior leaflet mates or engages with the anterior leaflet a. Anterior lateral ALT and posterior medial PMT trigones are at anterior leaflet A and posterior leaflet first tip P₁And a third tip P₃Are indicated accordingly. These junctions are also known as the interphalangeal commissures.

【0008】 As described above, with reference to fig. 2A, the mitral annulus has a deformed "D" shape with a straight portion, or anterior face, extending between the antero-lateral ALT and posteromedial PMT trigones. The longest edge of the mitral annulus defines a major axis 22 and the shortest edge defines a minor axis 24. The layshaft 24 normally bisects the forward lobe a. Although the mitral annulus is not circular, its center 26 may be defined at the intersection of major axis 22 and minor axis 24. A radial line may extend from this imaginary center 26 outwardly through the anterior lateral ALT and posterior medial PMT trigones, indicating the separation angle phi therebetween. The separation angle phi varies from patient to patient, but is typically about one third, or 120 deg. around the circumference of the mitral annulus.

【0009】 A large number of prosthetic heart valves have been proposed in the art, and generally do not take much into account the unique properties of the different valve annuli. In particular, few attempts have been made to modify prosthetic valves to better conform to the mitral annulus.

Disclosure of Invention

【0010】 In accordance with one aspect of the present invention, a sewing ring (sewingring) of a prosthetic heart valve includes a suture-permeable ring member configured to surround an axis defining an inflow-outflow direction. The ring member has substantially planar inflow and outflow ends including at least one portion that is axially elevated relative to adjacent portions of the outflow end. The axially-raised portion may gradually curve upwardly from the adjacent portion of the outflow end to a height of about 50% of the maximum axial dimension of the ring member. In one embodiment, the maximum axial dimension of the ring member is about 4 millimeters. Preferably, there are two axial lifting portions on the outflow end, which are approximately 120 ° apart.

【0011】 The compliance (flexibility) of the ring member at a mid-point between the axially-raised portions, which mid-point is located over a shorter distance between the axially-raised portions, is less than at a location diametrically opposite the point. The ring member may be constructed of a molded polymer having a plurality of radial walls defining a space therebetween, with two separate axially-raised portions at the outflow end. In one embodiment, the radial wall is thicker at a midpoint between the axially-raised portions that is located a shorter distance between the axially-raised portions than at a location diametrically opposite the midpoint. In another embodiment, the space at the midpoint between the axially-raised portions is less than the space at a location diametrically opposite the midpoint, wherein the midpoint is located a shorter distance between the axially-raised portions. Alternatively, the ring member is constructed from a rolled fabric having two spaced axially-raised portions at the outflow end, the fabric being rolled more closely at a midpoint between the axially-raised portions that is located a shorter distance therebetween than at a location diametrically opposite the midpoint.

【0012】 It is another aspect of the present invention to provide a sewing ring for a prosthetic heart valve, the sewing ring including a sewing permeable ring member disposed about an axis defining an inflow-outflow direction, the ring member having a variable compliance (compliance) about its periphery. The ring member may be constructed of a molded polymer having a plurality of radial walls defining spaces therebetween. In one embodiment the radial wall around one side is thicker than the radial wall around the other side, while in an alternative embodiment the space around one side is smaller than the space around the other side. Alternatively, the loop members may be formed from a polymer fabric, such as a non-woven or rolled fabric. In the latter case, the fabric on one side is rolled more tightly than the other side.

【0013】 In a particularly preferred embodiment, the sewing ring forms part of a mitral heart valve for implantation at a mitral valve annulus having two trigones spaced apart in relation to the anterior and posterior aspects. The loop member then has a front side and a rear side, wherein the loop member is more compliant around its rear side than around its front side. The ring member may be disposed about the shaft so as to define an inflow end and an outflow end, and the outflow end includes two portions generally defining a front side thereof that are axially elevated relative to adjacent portions. The two axially raised portions on the outflow end are preferably spaced about 120 apart.

【0014】 According to a further aspect, a prosthetic mitral heart valve is provided for implantation at a mitral valve annulus. The mitral valve annulus has two anterior trigones separated by about 120 °. The heart valve includes a stent frame defining an orifice formed about an axis along an inflow-outflow direction, and a plurality of leaflets mounted for movement on the stent frame to provide a one-way valve in the orifice. The sewing ring is attached to and positioned around the support frame to attach the heart valve to the mitral valve annulus. The sewing ring has an inflow end and an outflow end, and the outflow end includes two axially raised portions opposite the remainder of the outflow end, the two axially raised portions being spaced apart so as to align with the two trigones when implanted.

【0015】 In a prosthetic mitral heart valve, the stent frame may have an undulating shape including three axial commissures extending in the outflow direction alternating with three cusps extending in the inflow direction. In this case, the two commissures are located adjacent to the two axially-raised portions of the sewing ring, and the heart valve includes three flexible leaflets mounted around a undulating stent frame. Alternatively, the support frame has a generally annular configuration, and the heart valve includes two rigid leaflets mounted for rotational movement in the support frame. In one embodiment, the axially-raised portions gradually curve upward from the adjacent portion of the outflow end to a height of about 50% of the maximum axial dimension of the sewing ring. In addition, the suture-permeable ring member has a variable compliance about its circumference.

【0016】 The present invention also provides a method of implanting a prosthetic mitral heart valve at a mitral valve annulus, wherein the annulus has two spaced apart anterior trigones. The method comprises the following steps:

providing a prosthetic mitral heart valve having an outwardly directed sewing ring to connect the heart valve to the mitral valve annulus, the sewing ring having an inflow end and an outflow end, wherein the outflow end includes two axially raised portions opposite the remainder of the outflow end, the two portions being spaced so as to align with the two anterior trigones; and

a prosthetic mitral heart valve is implanted into the mitral valve annulus so that the two axially-raised portions are positioned adjacent the two anterior trigones of the annulus.

【0017】 Preferably, the sewing ring comprises a suture-permeable annulus member, and the implanting step comprises suturing the sewing ring to the mitral valve annulus. For example, the sewing ring may be a sewing permeable ring member surrounded by a fabric covering. A prosthetic mitral heart valve can have three axial commissures that extend into the ventricle in the outflow direction when the valve is implanted, the first two commissures being positioned at the same location around the heart valve as the two axially-raised portions, and the third commissure being positioned equidistant from the first two commissures. In this case, the method includes tilting the prosthetic mitral heart valve at an angle relative to the plane of the annulus such that the third commissure angles away from the adjacent ventricular wall and reduces the chance of contact therebetween.

【0018】 In another embodiment, the sewing ring is less compliant at the axially-raised portions than at diametrically opposite locations of the axially-raised portions. The method may be applied to the mitral annulus having portions that are more calcified than other portions of the annulus. For this pathological condition, the method includes implanting a prosthetic mitral heart valve in the mitral valve annulus such that a relatively more compliant portion of the ring member is positioned adjacent to a more calcified mitral valve annulus portion.

【0019】 Another inventive method of the present invention includes implanting a prosthetic heart valve at a patient's heart valve annulus by first providing a prosthetic heart valve having an outwardly directed sewing ring to attach the heart valve to the valve annulus. The sewing ring has a suture-permeable annular member configured about an axis defining an inflow-outflow direction and having variable compliance about its circumference. The method includes implanting a prosthetic heart valve in the annulus such that portions of the annulus member that are relatively more compliant than diametrically opposed portions are located at predetermined locations around the annulus. For example, the ring may have a more calcified face than the remainder of the ring, and wherein the implanting step comprises placing the relatively more compliant ring member portion adjacent the more calcified annulus face. More specifically, the method is applicable to a mitral valve annulus having an anterior face and a posterior face, and wherein the ring member has an anterior side connected to the anterior face of the mitral valve annulus and a posterior side connected to the posterior side of the mitral valve annulus, and a relatively more compliant portion of the ring member is located on the posterior side thereof.

【0020】 A further understanding of the nature and advantages of the present invention will be set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.

Drawings

【0021】 FIG. 1 is a view of the heart, as seen in a partial vertical section along the anterior-posterior plane, illustrating the left ventricle LV and the valves associated therewith;

【0022】 FIG. 2 is a view of the superior aortic and mitral valve annuluses with the corresponding atria removed;

【0023】 Fig. 2A is a schematic view of the mitral annulus corresponding to that seen in fig. 2, the schematic indicating the most prominent anatomical features and terminology;

【0024】 FIG. 3A is a partial vertical sectional view along the anterior-posterior plane illustrating conventional placement of a prosthetic heart valve in the mitral annulus in the prior art;

【0025】 FIG. 3B is a partial vertical sectional view along the anterior-posterior plane illustrating placement of the prosthetic heart valve of the present invention in the mitral annulus, indicating a slightly angled implant position;

【0026】 FIG. 4 is a perspective view of an exemplary undulating heart valve support frame;

【0027】 FIG. 5 is a perspective view of three flexible leaflets assembled with the stent frame of FIG. 4 and used in an exemplary heart valve of the present invention;

【0028】 FIG. 6 is a perspective view of an assembled flexible leaflet mitral heart valve of the present invention having a contoured sewing ring;

【0029】 FIGS. 7A and 7B are perspective views of the outflow and inflow ends, respectively, of an exemplary ring member of the sewing ring of the present invention;

【0030】 FIG. 8 is an elevational view of one side of the ring member of the sewing ring;

【0031】 FIG. 9 is a plan view of the inflow end of the ring member;

【0032】 FIG. 10 is a plan view of the outflow end of the ring member showing a plurality of radial walls defining variable sized spaces therebetween;

【0033】 FIG. 10A is an enlarged view of a portion of the outflow end of the ring member with details showing different sized spaces;

【0034】 FIG. 11 is an elevational view of the other side of the ring member, and FIG. 11A is a radial cross-sectional view thereof;

【0035】 FIG. 12 is a further elevational view of the ring member, FIG. 12A being a radial cross-sectional view thereof;

【0036】 FIG. 12B is an enlarged view of a radial cross-section of the ring member;

【0037】 FIG. 13 is a perspective view of an assembled rigid leaflet mitral heart valve of the present invention having a contoured sewing ring; and

【0038】 13A and 13B are radial cross-sectional views of the contoured sewing ring of FIG. 13 taken along respective lines 13A-13A and 13B-13B, showing segments having different degrees of compliance.

Detailed Description

【0039】 The present invention provides an improved prosthetic heart valve for the mitral annulus. The prosthetic heart valves disclosed herein have a contoured sewing or sewing ring, sometimes known as a sewing cuff (sewing cuff), that better matches the anatomy of the mitral annulus and positions the valve at an angle relative to the plane of the ring. The sewing rings have at least one axially raised portion at their outflow end that mates with the anterior aspect of the mitral annulus. In the illustrated embodiment, there are two such axially-raised portions, each corresponding to one of the fibrous trigones of the mitral annulus, while the posterior side of the outflow end is generally planar. However, it will be appreciated that the posterior side of the outflow end may also be contoured or have a shape other than the plane of the annulus.

【0040】 The sewing ring disclosed herein is useful with any type of prosthetic heart valve, bioprosthetic or medical flexible or rigid leaflets. The primary illustrated embodiment is a flexible leaflet valve, although a rigid leaflet valve is shown in fig. 13. Those skilled in the art will appreciate that certain advantages realized by the contoured sewing ring may be applied to all prosthetic mitral heart valves, regardless of the occluder (occluder) configuration. For example, although separate flexible leaflets are shown, the present invention may also be used with whole xenograft (e.g., porcine) valves. Moreover, while the term "sewing ring" is used in this application, it is to be understood that non-sewn attachment structures may be used to implant the heart valve of the present invention. For example, staples (staples), glue, hooks, barbs, etc. are also contemplated for attaching the sewing ring to the mitral annulus.

【0041】 As a final word in the introduction, various angular values are provided to separate the axially-raised portion from the other portions of the sewing ring shown. To some extent, these angular values depend on the surrounding mitral valve anatomy and to some extent on the occluder structure. For example, it is often the case that a whole porcine valve has three leaflets, but the commissures are not equally spaced around the circumference of the valve. The typical distribution of commissures has a spacing of 115/120/125 instead of 120/120. Thus, for example, a slightly offset distribution of the porcine valve commissures may require a corresponding offset of the stent structure commissures and the axially-raised portions of the sewing ring. Also, the natural trigones of the mitral annulus may be less than 120 ° apart or greater than 120 ° apart. Thus, in this context, it is understood that the term "approximately 120" includes a range of angular values of about 20 on each side, or between 100-140.

【0042】 Before discussing in detail exemplary prosthetic heart valve configurations, one major advantage of the present invention is described with reference to fig. 3A and 3B. Fig. 3A shows a prosthetic heart valve 30 with an annular, planar sewing ring 32 implanted in the mitral annulus position. The planar nature of the sewing ring 32, and in particular, its outflow end 34, positions the valve 30 so that it is parallel to the mitral annulus plane MAP, as described above. The blood flow arrow 36 in the outflow direction extends generally perpendicular to the MAP into the left ventricle LV. The prosthetic heart valve 30 is shown having a plurality of outflow commissures 38 supporting flexible leaflets 40 therebetween. Typically, two outflow commissures 38 are positioned adjacent the anterior trigones (not shown) of the mitral annulus, while a third commissure (shown on the right) is on the posterior side and extends into the left ventricle LV near the inner wall. The gap G between this third commissure 38 and the inner wall of the left ventricle LV₁Is shown.

【0043】 Figure 3B illustrates a prosthetic heart valve 50 of the present invention implanted at the mitral annulus location. The sewing ring 52 has a contoured outflow end 54 that includes a portion 56 that is axially convex in the outflow direction relative to adjacent portions of the outflow end, and which is located on the anterior side. The presence of the bulge 56 lifts the side of the valve 50 and positions it so that the sewing ring 52 is inclined at an angle δ relative to the mitral annulus plane MAP. The angle δ is preferably between 3 ° and 15 °, more preferably about 7 °. The blood flow arrow 58 in the outflow direction extends into the left ventricle LV at an angle that is not completely perpendicular to the MAP.

【0044】 As with the previously described valve 30, the prosthetic heart valve 50 of FIG. 3B has a plurality of outflow commissures 62 supporting flexible leaflets 64 therebetween. Two outflow commissures 62 are positioned adjacent the anterior trigones (not shown) of the mitral annulus, while the third commissure (shown on the right) is on the posterior side and extends to the left ventricle LV near the inner wall. This third commissure 62 and the left ventricleGap G between inner walls of LV₂Is also shown. Gap G₂Is larger than the gap G shown in FIG. 3A₁This is due to the angle of inclination δ of the valve 50. The increased spacing between the commissures 62 closest to the inner wall of the left ventricle LV helps prevent contact therebetween and thus reduces the chance of unnecessary damage and wear to the left ventricle.

【0045】 Referring now to fig. 4-7, the basic construction of an exemplary prosthetic mitral heart valve 50 of the present invention is described below. Fig. 4 shows a heart valve stent frame 70 that supports the aforementioned leaflets 64 and defines the valve commissures 62 of fig. 3B. The stent frame 70 includes commissures 72a, 72b, 72c on the outflow end alternating with cusps 74a, 74b, 74c on the inflow end. The ends of each pair of adjacent cusps 74 converge asymptotically to form upstanding commissures 72 that terminate in cusps and that each extend in a direction opposite the arcuate cusps and have a relatively small radius. If viewed in plan from above, the outer periphery of the stent frame 70 is substantially tubular in shape and the three commissures 72 are equally spaced at approximately 120 apart. Desirably, the commissures 72 are angled slightly radially inward from adjacent the cusps 74 such that the stent frame 70 defines an approximately conical shape.

【0046】 The prosthetic valve 50 is a tri-leaflet valve having three flexible leaflets 64a, 64b, 64c (fig. 5). While three leaflets are preferred and mimic the natural aortic valve, the principles of the present invention can be applied to the construction of prosthetic valves having two or more flexible leaflets. Each leaf 64 includes an arcuate lower tip edge 66 that terminates in an upstanding commissure region 67 and defines, therewith, a "peripheral edge" of each leaf. Each lobe 64 includes a combined or free edge 68 opposite the tip edge 66. In the assembled valve 50, the cusp edges 66 and commissure regions 67 are fixed around the periphery of the valve, and have free edges 68 that can meet or "coapt" in the middle.

【0047】 In the construction of the exemplary heart valve 50, the peripheral edges (66, 67) of the leaflets 64 are attached to a stent frame 70, the stent frame 70 thus defining the shape of the three-dimensional stent structure of the leaflets and flow orifices. The three leaflets 64a, 64b, 64c are assembled in the manner shown in fig. 5, and the support frame 70 is lowered over the top of the subassembly so that the juxtaposed peripheral edges of each two adjacent leaflets are disposed in the axial space defined by the commissures 72 of the support frame 70. Although not shown, fabric covers the stent frame 70 and provides an attachment structure to which the leaflets 64 are attached, typically with stitching. As described above, other valve configurations may not utilize a stent frame 70, but may still incorporate a contoured sewing ring 52.

【0048】 The assembled prosthetic mitral heart valve 50 is shown in fig. 6. The proximal side of the valve 50 is the anterior side, while the opposite side is the posterior side. The aforementioned commissures 62a, 62b, 62c project "upwardly" (upwardly) in the direction shown towards the outflow end of the valve 50. The terms "upward" and "axial-lift" as used herein can be seen in fig. 6 with the outflow end upward, with reference to the orientation of the valve 50. Of course, the valve 50 can be inverted to reverse these orientations, as seen previously in fig. 3A and 3B.

【0049】 The sewing ring 52 surrounds the fabric-covered cusps 74 of the support frame 70 and is attached thereto with a sewing thread or other means. As discussed above, the outflow end 54 of the sewing ring 52 includes at least one portion 56 that projects axially in the outflow direction relative to the adjacent portion of the sewing ring outflow end. In the illustrated embodiment, there are two such axially-raised portions 56 that are approximately 120 ° apart and located radially outward from the two commissures 62a, 62 b. Radial lines 80 drawn across the outflow end 54 represent the apices of these axially-raised portions 56a, 56b, and may be included as position markers on the exterior of the sewing ring 52.

【0050】 The preferred construction of the sewing ring 52 includes a fabric-covered seam-permeable (fabric-permeable) ring member 90, as shown in FIGS. 7A and 7B. The ring member 90 has a substantially planar inflow end 92 and a contoured outflow end 94 that includes two axially raised portions 96a, 96 b. Preferably, the loop member 90 is formed from a suture-permeable, biocompatible polymer, such as silicone, and has a plurality of walls defining spaces or cells (cells) therebetween. As shown in fig. 7A, the space is open to an outflow end 94, while fig. 7B shows a substantially continuous, closed inflow end 92.

【0051】 Fig. 8-12 illustrate exemplary structural details of the suture permeable loop member 90. Fig. 8 shows in elevation the axial height of the ring member 90 and the raised portions 96a, 96b relative to the remainder of the outflow end 94. The overall axial dimension of the ring member 90 is shown on the left as H. Nominal height h of a plurality of ring members₁Approximately half the total ring member height H, e.g., the additional height H of the axially raised portions 96a, 96b₂. In other words, the axially-raised portions 96a, 96b are raised upwardly from adjacent portions of the outflow end 94 to a height of 50% of the maximum axial dimension of the ring member 90. According to one embodiment, the axially-raised portions 96a, 96b are raised upwardly from adjacent portions of the outflow end 94 by a height h of about 2 millimeters₂And the overall height H of the ring member 90 is about 4 mm.

【0052】 In a preferred embodiment, the axially-raised portions 96a, 96b are gradually curved upwardly from adjacent portions of the outflow end to their apices and are substantially symmetrical about the circumferential midpoint. As described above, the lifting portions 96a, 96b of the ring member 90 are provided on the front side thereof. The rear side 97 of the outflow end 94 is substantially planar and parallel to the inflow end 92, as shown in FIG. 8. Fig. 11 shows the symmetry between the two raised portions 96a, 96b with the slot 98 in the middle. Fig. 12 shows the raised portions 96a, 96b, which curve downwardly away from each other to a substantially planar rear side 97. As defined herein, the raised portions 96a, 96b are raised relative to "adjacent portions" defined by the generally planar rear side 97 in one direction and the slot 98 on the front side in the other direction.

【0053】 Referring now to the plan view of the outflow end 94 in fig. 10, the short radial lines indicate apices 100 (described more fully below) at circumferential midpoints along the raised portions 96a, 96b of the inner protrusion 102. The entire plane of symmetry 104 is drawn by the ring member 90, the plane of symmetry 104 bisecting the two vertices 100 and passing through their centers. The plan view shows a symmetrical circumferential distribution about the apex 100 of the plane 104. Preferably, the apexes 100 are approximately 60 ° from the plane of symmetry, or approximately 120 ° from each other, as measured by the shortest distance around the ring member 90.

【0054】 The ring member 90 as seen in fig. 10-12 includes a plurality of walls defining spaces or cells therebetween. As best seen in fig. 12B, the relatively thick continuous inner wall 110 extends 360 ° around the ring member 90, as does the continuous tapered wall 112, which continuous tapered wall 112 flares radially outward in a direction out from the inner wall 110. As seen from the bottom of fig. 9, and in the cross-section of fig. 11, the bottom surface 114 of the inner wall 110 and the tapered wall 112 together define a continuous or integral wall of the ring member 90 facing the inflow direction. Fig. 12B is a radial cross-sectional view through one of the raised portions 96a, showing the outer portion tubular wall section 116, the wall section 116 projecting upwardly from the outermost edge of the conical wall 112. An inner tubular wall section 118 projects upwardly from the inner wall 110 in the region of the raised portion 96. A plurality of radial walls 120 connect the inner wall 110, the conical wall 112, and the outer wall segment 116 and define a plurality of cells or spaces 122 therebetween that are open to the outflow end 94. The combined shape of the upwardly projecting wall segments 116, 118 and the radial wall 120 therebetween define the raised portions 96a, 96b of the ring member 90.

【0055】 As seen in fig. 10, the radial walls 120 and spaces 122 therebetween are distributed around the entire circumference of the ring member 90. As seen in fig. 7A, the space 122 is open to the outflow end 94 of the ring member 90. Finally, the sewing ring 52 will be surrounded by fabric, as shown in fig. 6, and thus no space 122 will be visible in the finished valve. The space 122 provides a "well" structure for the ring member 90 and makes it highly compliant. Desirably, the ring member 90 is molded from a suitable biocompatible polymer, such as silicone or polyurethane, and the space 122 facilitates formation of the walls 110 and 120 and allows for easy release of the molded part.

【0056】 Fig. 10 and 10A also illustrate a preferred configuration for altering the compliance of the ring member 90 about its circumference. As described above, the apexes 100 of the raised portions 96a, 96b are spaced apart by approximately 120 °. Within this arc, the walls 120 are separated by a distance that is less than the distance at the opposite location from the arc, so that the space 122 is smaller and the ring member 90 is stiffer (stiff). More desirably, the illustrated angle θ is bisected by the plane of symmetry 104 and is therefore centered between the vertices 100. The lines forming the angle θ extend through a radial wall 120, the wall 120 defining a transition between differently sized spaces 122. In one embodiment, the angle θ is 90 °, but ideally the angle θ is between 80-120 °.

【0057】 The enlarged view of fig. 10A best illustrates the transition between the differently sized spaces 122. The radial wall 120' separates the first space 122a from the second space 122 b. The first space 122a spans an angle α, and the second space 122b spans an angle β, where β > α. This angular relationship results in S₁And S₂As taken at a nominal radius through the radial midpoint of each space 122a, 122b, respectively, is dependent upon the size of the ring member 90. It will be appreciated that heart valves are manufactured in a variety of sizes, typically between 21-35 mm in outer diameter, and therefore the sewing ring 52 and the ring member 90 are provided in different sizes. It will be appreciated that, otherwise identical, the ring member 90 is more compliant where the space 122b is larger.

【0058】 The following table provides exemplary dimensions for the ring member 90 for a 27 mm prosthetic valve, where each space 122 is referred to as a "cell". In this example, the cell walls 120 are all of equal thickness.

Description of the invention	Variables of	Size of
			Inner radius of cell	R1	0.633 inch
Outer radius of the cell	R2	0.710 inch
			Mean radius	RCenter	0.672 inch
Small unit (122a) angle	α	6.88°±5°
			Large unit (122b) corner	β	9.30°±5°
Small unit arc length of central radius	S1	0.081 + -0.059 inches
			Large unit arc length of central radius	S2	0.109. + -. 0.059 inches
Small unit wall angle	λ	2.00°±1°
			Large unit wall angle	μ	2.00°±1°
Small cell wall arc length of central radius	t1	0.023 + -0.01 inches
			Center radius large cell wall arc length	t2	0.023 + -0.01 inches

【0059】 As described above, the arc between the raised portions 96 depicted by the apex 100 in fig. 10 subtends an angular segment of the member 90, which angular segment of the member 90 is intentionally positioned anterior to the mitral annulus. Because the space 122a is generally smaller at the apex 100 (or at least within the angle θ), the anterior side of the member 90 and sewing ring 52 is therefore less compliant than the posterior side 97. A more compliant and less stiff posterior side 97 is therefore required so that the sewing ring 52 can more easily conform to the normally calcified tissue on the posterior aspect of the mitral valve annulus. However, in a preferred embodiment, the compliance of the sewing ring is less at a midpoint between the axially-raised portions 96 than at a location diametrically opposite from the midpoint, wherein the midpoint is disposed about the shorter distance between the axially-raised portions 96.

【0060】 Those skilled in the art will appreciate that designing the ring member 90 to be more compliant about its posterior side 97 is only one possible configuration that motivates a particular understanding of the tissue characteristics about the mitral annulus, in which case the posterior calcification is more highly calcified. Of course, the compliance feature of the ring around the periphery may be customized in other ways, for example, to be more compliant around the anterior side. In general, the present invention contemplates a sewing ring 52 having variable compliance around the periphery. For example, one contemplated configuration is the alternation of large and small cells, in which case the alternating high and low compliance regions are smaller and more frequent, as opposed to being isolated on one side or the other.

【0061】 Referring also to FIG. 10A, in addition to varying the spacing between the walls 120, the compliance of the sewing ring 52, or more particularly the ring member 90, around the periphery may be varied in other ways. For example, the wall 120 itself may be provided with different thicknesses, such as by making the angles λ and μ in the above table unequal. In the less compliant (stiffer) section indicated to the left of the transition wall 120', the radial wall 120 may have a thickness t₁And may have a thickness t on the right side of the transition wall 120₂，t₂＜t₁(in terms of angle, λ > μ). By making the radial wall 120 thinner around the rear side 97 of the ring member 90, this area is more compliant. Also, varying the thickness of the radial wall 120 may be combined with varying the size of the space 122 to create a greater difference in compliance. Also, the different transitions of the wall 120' between the different compliance regions may be replaced by more gradual transitions.

【0062】 It will also be appreciated that the configuration of the sewing ring may be different than that shown in figures 7-12. Constructing the sewing ring in a molded silicone "well" configuration has certain significant advantages, as shown, but the overall benefit of providing an axially raised portion and different compliance on the anterior side of the outflow end of the sewing ring can be achieved in a variety of configurations. For example, other polymers (e.g., polyurethane) may be used to form the well structure, or the particular structure of the walls and spaces may be modified. Certain biocompatible fabrics may also be used to form the sewing ring, such as non-woven fabrics, non-extruded polyester, or polyethylene terephthalate. In practice, one particularly useful method of forming seaming loops is to roll or fold such a fabric into the desired contour and then heat-form the fabric into the desired shape. Such rolled or folded cloth or fabric may also be made with different degrees of compliance around the periphery of the sewing ring. Such a fabric is made stiffer than the back side 97, for example, by rolling it more tightly around the front side of the sewing ring. Accordingly, unless specifically stated, it is to be understood that the present invention is not limited to molded "well-like" polymeric internals of sewing rings.

【0063】 Certain other structural details of the exemplary ring member 90 that facilitate assembly with other components of a flexible leaflet heart valve are shown in the perspective views of fig. 7A and 7B and the detailed views of fig. 11-12. More particularly, fig. 7A best illustrates the inner protrusion 102 upon which the three cusps 74a, 74b, 74c (fig. 4) of the stent frame 70 of the assembled valve 50 rest. The inner protrusion 102 is also seen in cross-section in fig. 11, 12A and 12B and transitions from a horizontal platform 132 at the midpoint of its rear side 97 to a small horizontal flange 134 and from there up to the apex 100 of the raised portions 96a, 96B. The projection 102 descends to another small horizontal flange 136 midway between the forward midpoint and the apex 100. As shown in fig. 11A, the projection 102 is substantially horizontal at its lower end and transitions with a slight inward and downward angle as it rises axially upward and reaches the apex 100, as shown in the enlarged view of fig. 12B.

【0064】 The assembled configuration of the valve 50 essentially comprises covering the stent frame 70 having the flange extending outwardly therefrom with fabric, as shown in fig. 4. The ring member 90 is also covered by fabric and the peripheral edge of the leaf 64 is sandwiched between and secured to the fabric covering of the support frame 70 and the ring member 90. As described above, the tip 74 of the support frame 70 closely conforms to the contour of the inner protrusion 102, and the various components that are stitched together are made relatively dimensionally stable. That is, the stent frame 70 is prevented from migrating in the inflow direction by the inner protrusion 102 through the ring member 90. A more complete discussion of these manufacturing techniques is provided in U.S. Pat. No.6,585,766 to Huynh et al and U.S. application No.11/039,522, entitled ANATOMICALLYCALLYAPROROTATE PROSTHETIC MITRAL HEART VALVE, the disclosures of which are both expressly incorporated herein by reference.

【0065】 The contours of the raised portions 96a, 96b are also important to enhance contact between the sewing ring 52 and the surrounding mitral annulus, as well as providing the aforementioned benefits of lifting the anterior side upward to tilt the entire valve away from the left ventricular wall. As best seen in the front views of fig. 11 and 12, each lift portion 96a, 96b defines a smooth curvature with no abrupt corners. Fig. 11 shows the symmetry between the two raised portions 96a, 96b, wherein the front side of the outflow end 94 comprises a gradually decreasing height from the raised portions to the trough 98. The slots 98 have approximately the same height as the opposite side of the outflow end 94 of the ring member 90, as seen from the left side of fig. 12. Thus, the circumferential arc about which the axial dimension of the ring member 90 changes from the highest point of the raised portions 96a, 96b to the lowest point of the groove 98 is approximately 60 °. On the other hand, referring to fig. 12, there is a small gradual transition between the highest point of the raised portions 96a, 96b and the generally planar rear side 97, although the transition is still smooth. The circumferential arc distance between the top of the raised portions 96a, 96b and the planar rear side 97 of the outflow end 94 is about 20 °.

【0066】 Referring now to fig. 13, an alternative prosthetic heart valve 150 of the present invention includes a mechanical valve member 152 connected to a contoured sewing ring 154 of the present invention. The valve member 152 includes rigid leaflets 156a, 156b that are connected for rotational movement within a surrounding support frame 158. The sewing ring 154 is secured around the periphery of the support frame 158. From this perspective, the inflow end of the valve member 152 is upward and the outflow end is downward. Two raised portions 160a, 160b are provided within the sewing ring 154 much like the flexible leaf embodiment previously described. Desirably, the raised portions 160a, 160b are circumferentially spaced on the anterior side of the sewing ring 154 so as to correspond to natural triangles (typically about 120 °). It should be noted that the mechanical valve member 152 is typically rotatable within the surrounding support frame 158, and thus the orientation shown with respect to the contoured sewing ring 154 should not be taken as limiting. The sewing ring 154 has a fabric outer covering 162 that may cover an inner well-like ring member as described above, or may simply be the outer layer of a rolled or folded fabric construction.

【0067】 Figures 13A and 13B are radial cross-sectional views of the contoured sewing ring 154 taken along lines 13A-13A and 13B-13B, respectively, of figure 13, illustrating segments of different compliance. In this embodiment, the sewing ring 154 is made of a rolled fabric construction, and the varying softness is achieved by rolling the fabric more tightly on one side 170 than the other side 172. Ideally, the more tightly wrapped and thus less compliant side 170 is on the anterior side of the mitral valve 150, while the more loosely wrapped and thus more compliant side 172 is on the posterior side. In another commercial configuration, a non-woven polymer fabric and polyester cloth are used, somewhat like a pillow filler. In the latter configuration, the polyester cloth may be more tightly packed around one side relative to the other side of the sewing ring 154.

【0068】 It will be appreciated by those skilled in the art that various changes can be made to the examples and embodiments described in this provisional application without departing from the scope of the invention as claimed. The specific embodiments of the invention described herein are therefore to be understood as examples of the broader inventive concepts disclosed in the application.

Claims (24)

1. A sewing ring for a prosthetic heart valve, comprising:

a suture-permeable loop member disposed about an axis defining an inflow-outflow direction, the loop member having a substantially planar inflow end and having an outflow end including at least a portion that is axially raised relative to an adjacent portion of the outflow end.

2. The sewing ring of claim 1, wherein the axially-raised portion gradually curves upward from the adjacent portion of the outflow end to a height of about 50% of the maximum axial dimension of the annular member.

3. The sewing ring of claim 2, wherein the maximum axial dimension of the annular member is about 4 millimeters.

4. The sewing ring of claim 1, wherein there are two axially-raised portions on the outflow end, the two axially-raised portions being approximately 120 ° apart.

5. The sewing ring of claim 4, wherein the annular member has a compliance at a midpoint between the axially-raised portions that is less than a compliance at a location diametrically opposite the midpoint, wherein the midpoint is located a short distance around the axially-raised portions.

6. The sewing ring of claim 1, wherein the annular member comprises a molded polymer having a plurality of radial walls defining spaces therebetween, wherein there are two axially-raised portions spaced apart at the outflow end, and wherein the radial walls are thicker at a midpoint between the axially-raised portions than at a location diametrically opposite the midpoint, wherein the midpoint is located a short distance around the axially-raised portions.

7. The sewing ring of claim 1, wherein the annular member comprises a molded polymer having a plurality of radial walls defining a space therebetween, wherein there are two axially-raised portions spaced apart at the outflow end, and wherein the space is smaller at a midpoint between the axially-raised portions than at a location diametrically opposite the midpoint, wherein the midpoint is located a short distance around the axially-raised portions.

8. The sewing ring of claim 1, wherein the annular member comprises a rolled fabric, wherein there are two spaced axially-raised portions at the outflow end, and wherein the fabric is rolled more tightly at a midpoint between the axially-raised portions that is located a shorter distance around the axially-raised portions than at a location diametrically opposite the midpoint.

9. A sewing ring for a prosthetic heart valve, comprising:

a suture-permeable loop member disposed about an axis defining an inflow-outflow direction, the loop member having a variable compliance about its periphery.

10. The sewing ring of claim 9, wherein the annular member comprises a molded polymer having a plurality of radial walls defining spaces therebetween, and wherein the radial walls around one side are thicker than the radial walls around the other side.

11. The sewing ring of claim 9, wherein the annular member comprises a molded polymer having a plurality of radial walls defining spaces therebetween, and wherein the spaces around one side are smaller than the spaces around the other side.

12. The sewing ring of claim 9, wherein the ring member comprises a polymer fabric.

13. The sewing ring of claim 12, wherein the annular member comprises a rolled fabric, and wherein the fabric is rolled more tightly around one side than around the other side.

14. The sewing ring of claim 9, wherein the sewing ring forms a component of a mitral heart valve implanted at a mitral valve annulus having two trigones spaced about an anterior face and a posterior face, and wherein the annular member has an anterior side and a posterior side, wherein the annular member is more compliant around its posterior side than around its anterior side.

15. The sewing ring of claim 14, wherein the annular member is disposed about the shaft so as to define an inflow end and an outflow end, and the outflow end includes two portions generally defining an anterior side thereof, the two portions being axially raised relative to adjacent portions.

16. The sewing ring of claim 15, wherein the two axially-raised portions on the outflow end are separated by about 120 °.

17. A prosthetic mitral heart valve for implantation at a mitral valve annulus, the annulus having two anterior trigones spaced about 120 ° apart, the prosthetic mitral heart valve comprising:

a support frame defining an orifice about an axis along an inflow-outflow direction;

a plurality of leaflets mounted for movement on the stent frame to provide a one-way valve within the orifice; and

a sewing ring connected to and positioned around the support frame to connect the heart valve to the mitral valve annulus, the sewing ring having an inflow end and an outflow end, wherein the outflow end includes two axially-raised portions opposite the remainder of the outflow end, the two axially-raised portions being spaced so as to align with the two anterior trigones when implanted.

18. The heart valve of claim 17, wherein the support frame has an undulating shape including three axial commissures extending toward the outflow direction alternating with three cusps extending toward the inflow direction, two of the commissures are disposed adjacent the two axially-raised portions of the sewing ring, and the heart valve includes three flexible leaflets mounted around the undulating shape of the support frame.

19. The heart valve of claim 17, wherein the stent frame has a generally annular configuration and the heart valve includes two rigid leaflets mounted for rotational movement within the stent frame.

20. The heart valve of claim 17, wherein the axially-raised portions are gradually curved upward from the adjacent portion of the outflow end to a height of about 50% of a maximum axial dimension of the sewing ring.

21. The heart valve of claim 17, wherein the suture-permeable annular member has variable compliance about its periphery.

22. The heart valve of claim 21, wherein the sewing ring is less flexible at a midpoint between the axially-raised portions that is located a shorter distance between the axially-raised portions than at a location diametrically opposite the midpoint.

23. The heart valve of claim 22, wherein the sewing ring comprises a sewing-permeable annular member surrounded by a fabric covering, the annular member having a plurality of radial walls defining spaces therebetween, and wherein the radial walls are thicker at a midpoint between the axially-raised portions than at a location diametrically opposite the midpoint, wherein the midpoint is located a shorter distance between the axially-raised portions.

24. The heart valve of claim 22, wherein the sewing ring comprises a sewing-permeable annular member surrounded by a fabric covering, the annular member having a plurality of radial walls defining spaces therebetween, and wherein the spaces are smaller at a midpoint between the axially-raised portions than at a location diametrically opposite the midpoint, wherein the midpoint is located a shorter distance between the axially-raised portions.