Asymmetric mitral annuloplasty band

Abstract

An annuloplasty band and method of implantation are provided that are shaped and sized to avoid adjacent aortic valve structures, providing better protection against dehiscence along the muscular mitral annulus. [Solution] The band is asymmetric and, when implanted, spans a longer distance around the posterior commissure of the mitral valve annulus than the anterior commissure. The band has a saddle shape with a posterior, upward arcuate portion centered on the short axis of the mitral valve annulus, with a longer span extending clockwise from the upward arcuate portion than counterclockwise. The longer span may be approximately 150°, while the shorter span extends approximately 90°. The set of rings may have different saddle profiles and different planar shapes for different sized bands. The method includes implanting the band so that it extends across the posterior leaflet and extends a short distance beyond the posterior commissure outside the anterior leaflet.

Description

[Technical Field]

[0001] This application claims the benefit of U.S. Patent Application No. 62 / 173,294, filed June 9, 2015, which is expressly incorporated herein in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to annuloplasty bands, and more particularly to mitral annuloplasty bands. [Background technology]

[0003] In vertebrates, the heart is a hollow, muscular organ with four pumping chambers—the left and right atria and the left and right ventricles—each equipped with a one-way valve. Biological heart valves are identified as the aortic, mitral (or bicuspid), tricuspid, and pulmonary valves, arranged in annulus structures with dense fibrous rings attached directly or indirectly to the atrial and ventricular muscle fibers. Each annulus defines a flow orifice. The four valves prevent blood from flowing in the wrong direction during the cardiac cycle, i.e., preventing blood from backflowing through the valves. Blood flows from the venous system and right atrium through the tricuspid valve into the right ventricle, then from the right ventricle through the pulmonary valve to the pulmonary artery and lungs. The oxygen-rich blood then flows from the left atrium through the mitral valve to the left ventricle, and finally from the left ventricle through the aortic valve to the aortic / arterial system.

[0004] The mitral and tricuspid valves are defined by a collagenous annulus, each called the annulus, which forms part of the fibrous framework of the heart. The annulus provides peripheral attachments for the two cusps or leaflets (called the anterior and posterior leaflets) of the mitral valve and the three cusps or leaflets of the tricuspid valve. The natural valve leaflets flex outward as the valve opens, and the free edges of the leaflets coapt.

[0005] The free edges of the mitral valve leaflets are attached to chordae tendineae from two or more papillary muscles. Mitral valve abnormalities can occur due to stretching or even tearing of the chordae tendineae. A normally stretched valve can also malfunction due to dilation of the annulus. This condition, called annular dilation, commonly occurs as a result of myocardial damage. Additionally, the valve can be congenitally compromised or compromised by acquired disease. Multiple etiological studies have shown that mitral valve dysfunction can occur when the leaflets fail to coapt at peak systolic pressure. This can result in undesirable regurgitation of blood from the left ventricle to the left atrium.

[0006] Various surgical techniques can be used to repair diseased or damaged valves. A commonly used repair technique effective in treating insufficiency is valvuloplasty. Valvuloplasty often involves reshaping the valve annulus by attaching prosthetic annulus repair segments or rings to the annulus. For example, the goal of posterior mitral annulus repair is to advance the posterior mitral leaflet toward the anterior leaflet, allowing for better coaptation. Annuloplasty rings are designed to support the functional changes that occur during the cardiac cycle; that is, they prevent regurgitation by maintaining coaptation and valve integrity, while allowing for good hemodynamics during forward flow.

[0007] Annuloplasty rings typically comprise an inner substrate or core made of metal, such as a stainless steel or titanium rod or multiple bands, or flexible material, such as silicone rubber or polyethylene terephthalate (PET) (e.g., Dacron® PET, manufactured by Invista, Inc., Wichita, Kansas), covered with a biocompatible fabric or cloth so that the ring can be sewn to the fibrous annulus tissue. The more rigid core is typically surrounded by an outer covering of both silicone and fabric, providing an anchoring margin through which sutures can pass. Annuloplasty rings can be rigid or flexible and can have a variety of shapes in plan view, including continuous oval or circle, D-shape, kidney-shape, and discontinuous C-shape, and are sometimes referred to as bands. Examples are described in U.S. Patent Nos. 5,041,130, 5,104,407, 5,201,880, 5,258,021, 5,607,471, and 6,187,040. Most rigid and semi-rigid mitral valve annular rings have a kidney- or D-shaped configuration with a curved posterior segment coextensive with the posterior leaflet and an anterior segment coextensive with the anterior leaflet that is somewhat straighter than the posterior segment.

[0008] One popular annuloplasty ring is the partially flexible Carpentier-Edwards Physio® ring, available from Edwards Lifesciences, Irvine, California. The Physio® ring is a "semi-rigid" ring because it provides selective flexibility in the posterior section while preserving the remodeling effect through the rigid anterior section. Edwards Lifesciences' newer Physio II® ring also features up-and-down curvature to better fit the non-planar contours of the mitral annulus. Various other rings have arcuate posterior sections (e.g., U.S. Patent Nos. 6,805,710, 6,858,039, and 7,959,673) or other three-dimensional configurations. Summary of the Invention [Problem to be solved by the invention]

[0009] Although numerous designs are currently available or have been proposed in the past, there is a need for an annuloplasty ring that better conforms to the anatomy of the natural mitral valve annulus. [Means for solving the problem]

[0010] The present invention provides an annuloplasty band shaped and sized to avoid adjacent aortic valve structures, providing better protection against dehiscence along the muscular mitral annulus. The band is asymmetric in that, when implanted, it spans around one side of the mitral annulus longer than the other. Generally, the band extends across the posterior leaflet and extends a short distance beyond the posterior commissure lateral to the anterior leaflet. Looking down at the mitral valve with the anterior leaflet at the top and the posterior leaflet at the bottom, the minor axis in the superior-inferior direction can be visualized as passing through the midpoint of the leaflets, with the shorter dimension of the mitral annulus aligned along the minor axis. The annuloplasty band is discontinuous, with a midsection and two free ends, one on either side of the minor axis, and is implanted asymmetrically so that it extends around the mitral annulus toward the posterior commissure more than toward the anterior commissure, resulting in a greater circumferential length to the right than to the left. In other words, the asymmetrical placement of the implanted band is rotated counterclockwise (CCW) around the mitral valve annulus from a symmetrical placement with the center of the band on the minor axis. Furthermore, the exemplary annuloplasty band has an upwardly bulging or arcuate shape in the midsection about the minor axis, such that the lengths of the band on either side of the bulging high point are different. Specifically, the length extending counterclockwise (CCW) from the high point around the mitral valve annulus is longer than the length extending clockwise (CW). The exemplary discontinuous annuloplasty bands disclosed herein have a gap or opening between their free ends, which is configured or adapted to abut or be adjacent to the aortic valve location around the mitral valve annulus. This avoids fibrous structures associated with the aortic valve and provides better protection against dehiscence along the muscular mitral annulus.

[0011] The various asymmetric mitral annuloplasty bands disclosed herein are adapted to be implanted into the mitral valve annulus. The mitral valve annulus has a posterior surface with a posterior leaflet and an anterior surface with an anterior leaflet. When viewed from the inflow side of the mitral valve annulus, the mitral valve annulus generally defines a D- or kidney-shaped shape, with the anterior surface being straighter and more rounded than the posterior surface. A minor axis intersecting the mitral valve annulus and extending through it between the midpoint of the anterior surface and the midpoint of the posterior surface is shorter than a major axis perpendicular to the minor axis and extending through it. An anterior commissure and a posterior commissure are located on the mitral valve annulus at two junctions between the two leaflets. The anterior commissure is located clockwise from the midpoint of the posterior leaflet, and the posterior commissure is located counterclockwise from the midpoint of the posterior leaflet. The mitral valve annulus also generally defines a saddle shape, with the mitral valve annulus rising toward the left atrium at both the midpoint of the anterior surface and the midpoint of the posterior surface. In various embodiments, the annuloplasty band may be D-shaped or kidney-shaped, or may be oval, flat, or three-dimensional.

[0012] The asymmetric mitral annuloplasty band of the first embodiment has an elongated, discontinuous body portion including a generally rigid inner core surrounded by a suture-passable surface, the body portion defining an asymmetric shape that generally follows a portion of the shape of the mitral valve annulus, extending around the entire posterior surface and terminating in a first free end located approximately at the intersection of the long axis and the mitral valve annulus, and on the opposite side extending further toward the anterior surface beyond the intersection of the long axis and the mitral valve annulus and terminating in a second free end.

[0013] The second embodiment of the asymmetric mitral annuloplasty band has an elongated, discontinuous body portion including a generally rigid inner core surrounded by a suture-passable surface, the body portion defining an asymmetric shape beginning at a first free end adapted to be implanted adjacent the anterior commissure, extending in a counterclockwise (CCW) direction around the posterior surface, past the posterior commissure, through an intermediate section to the anterior surface, and terminating at a second free end.

[0014] Finally, a third embodiment of an asymmetric mitral annuloplasty band has an elongated, discontinuous body portion including a generally rigid inner core surrounded by a suture-passable surface, the body portion defining an asymmetric shape that generally follows the shape of the mitral valve annulus, extending around the entire posterior surface and including an upwardly arcuate portion corresponding to the bulge in the posterior surface, the body portion extending clockwise along a first span from the midpoint of the upwardly arcuate portion to a first free end and extending a longer distance along a second span from the midpoint of the upwardly arcuate portion to a second free end.

[0015] In any of the first three band embodiments, the entire circumferential span of the body portion preferably extends approximately 58-67% around the mitral valve annulus. For example, a first circumferential span of a portion of the body portion counterclockwise from the midpoint of the posterior surface extends approximately 37-42% around the mitral valve annulus, and a second circumferential span of a portion of the body portion clockwise from the midpoint of the posterior surface extends approximately 21-25% around the mitral valve annulus. Additionally, the first free end may be adapted to be implanted in the mitral valve annulus along its long axis. The first free end is preferably adapted to be implanted adjacent the anterior commissure, and the ring-shaped body portion extends counterclockwise within the anterior surface to the second free end.

[0016] In one of the first two band embodiments, the main body portion may include an upwardly arcuate portion centered at the midpoint of the rear surface. Preferably, the main body portion has a partial saddle shape with a first high point in the upwardly arcuate portion, two low points located approximately at the first free end and directly opposite the first free end, and a second high point at the second free end. Additionally, the main body portion may have a partial saddle shape with a first high point in the upwardly arcuate portion, two low points located approximately at the first free end and directly opposite the first free end, and a second high point at the second free end.

[0017] In a fourth embodiment, an asymmetric annuloplasty band includes a body portion having a top portion, a bottom portion, a first end, a second end, and a rigid or semi-rigid body portion extending between the first and second ends and including a first portion and a second portion. The first portion extends counterclockwise from a reference point along an orbit and terminates at the first end. The second portion extends clockwise from the reference point along an orbit and terminates at the second end. The length of the first portion is substantially different from the length of the second portion, and the orbit, when viewed from above, has an oval, D-, or kidney-shaped shape with a major axis extending left-to-right and a minor axis extending up-to-down that define a clock face, the reference point being the 6:00 position, the minor axis intersecting the orbit at the 12:00 and 6:00 positions, and the major axis intersecting the orbit at the 3:00 and 9:00 positions. The D- or kidney-shaped shape has a flatter portion above the major axis.

[0018] For the fourth embodiment band, the track is preferably D-shaped in top view, with a first portion of the body being longer than a second portion. The first portion preferably extends counterclockwise past the 3:00 position, e.g., with a first end located at about the 1:30 position or at about the 1:00 position. In one embodiment, the second portion does not extend clockwise to the 9:00 position, but may extend only to about the 8:30 position, although the second portion may continue to the 9:00 position.

[0019] A fifth embodiment of an asymmetric mitral annuloplasty band includes a rigid or semi-rigid open band having a top and a bottom, a posterior portion, and an anterior portion extending from one end of the posterior portion. In a plan view, the open band has a major axis and extends around a portion of a D- or kidney-shaped shape defining a long side having a first circumference and a short side having a second circumference shorter than the first circumference. The major axis and the D- or kidney-shaped shape share a first intersection point and a second intersection point, and the D- or kidney-shaped shape has a minor axis that shares a third intersection point with the long side and a fourth intersection point with the short side. The posterior portion of the open band extends from the first intersection point along the long side of the D- or kidney-shaped shape, and the anterior portion of the open band extends from the first intersection point along the short side of the D- or kidney-shaped shape.

[0020] In the fifth embodiment of the asymmetric annuloplasty band, when viewed from above, the long side is inferior and the short side is superior, with the first intersection on the right and the second intersection on the left. The posterior portion preferably does not extend to the second intersection of the D- or kidney-shaped configuration, but alternatively, the posterior portion may extend approximately to the second intersection of the D- or kidney-shaped configuration. The anterior portion desirably does not extend to the fourth intersection.

[0021] In either the fourth or fifth band embodiment, the asymmetric annuloplasty band has a saddle shape with a peak approximately at the intersection of the minor and major axes. Preferably, the saddle shape has a valley approximately at the intersection of the major axis. Furthermore, the body portion may have a core and a suture-passable cover disposed over the core. The core may comprise at least one of a cobalt-chromium alloy, a titanium alloy, and a stainless steel, or may be a solid core, multiple bands, or a braided core. The suture-passable cover preferably includes an elastomeric sleeve disposed around the core and a fibrous outer cover disposed over the elastomeric sleeve. The suture-passable cover may also have a suture flange projecting radially outward.

[0022] Another aspect of the present application is a set of progressive saddle-type asymmetric mitral annuloplasty bands, including any of the above-described asymmetric annuloplasty bands having multiple sizes, in which the ratio of the saddle height to the size of the asymmetric annuloplasty bands is not constant. For example, the ratio of the height to the size may increase with size, or the ratio of the height to the size may vary continuously with size. At least, the ratio of the height to the size may vary in at least one step with size. Also, the ratio of the minor axis length to the size of the set of bands may not be constant. For example, the ratio of the minor axis length to the size may increase with size or vary continuously with size. At least, the ratio may vary in at least one step with size.

[0023] Another aspect of the present application is a method for repairing an as-needed mitral valve, the mitral valve comprising an anterior leaflet including regions A1, A2, and A3; a posterior leaflet including regions P1, P2, and P3; an anterior medial commissure; a posterolateral commissure; and two trigones.

[0024] The first method includes securing a mitral valve band to a mitral valve annulus such that a first end of the mitral valve band is adjacent to the anterior leaflet, a body portion of the mitral valve band extends around one of the anterior medial commissure and the posterolateral commissure, and a second end of the mitral valve band is adjacent to the posterior leaflet or the other of the anterior medial commissure and the posterolateral commissure.

[0025] A second method of optionally repairing a mitral valve includes securing a mitral valve band having a first end and a second end to the annulus of the mitral valve, such that the first end is adjacent to the anterior leaflet and the second end is not adjacent to the anterior leaflet.

[0026] Finally, a third method of repairing a mitral valve includes securing a mitral valve band having a first end and a second end to the annulus of the mitral valve such that the first end is proximate to the anterior leaflet, and the mitral valve band is asymmetric with respect to a plane passing through A2 and P2.

[0027] In the above-described method, anchoring the mitral valve band preferably includes anchoring a first end proximate A3 and a second end proximate P1 or the anteromedial commissure, and desirably anchoring the mitral valve band to conform to the natural saddle shape of the mitral valve annulus.

[0028] A further understanding of the principles and advantages of the present invention will become apparent by reference to the following portions of the specification and drawings.

[0029] The features and advantages of the present invention will be better understood with reference to the specification, claims, and accompanying drawings. [Brief explanation of the drawings]

[0030] [Figure 1]FIG. 1 is a superior or plan view of a healthy mitral valve with the leaflets closed and coapted at peak contractile pressure during ventricular systole, showing key anatomical landmarks with diagrammatic lines indicating the circumferential reach of a band according to the present application. [Figure 2] 2 is a plan view of a mitral valve similar to FIG. 1 with an exemplary annuloplasty band implanted therearound in accordance with the present application. [Figure 3A] 1 is an elevational view of an exemplary annuloplasty band of the present invention. [Figure 3B] 1 is a plan view of an exemplary annuloplasty band of the present invention. [Figure 3C] 1 is a plan view of an exemplary annuloplasty band of the present invention. [Figure 3D] 1 is an elevational view of an exemplary annuloplasty band of the present invention. [Figure 4A] 3C is a cross-sectional view of an exemplary annuloplasty band taken along the corresponding cross-sectional line of FIG. 3B. [Figure 4B] 3C is a cross-sectional view of an exemplary annuloplasty band taken along the corresponding cross-sectional line of FIG. 3B. [Figure 5A] FIG. 4 is a plan view of an exemplary inner core for the annuloplasty band of FIGS. 3A-3D. [Figure 5B] 3E is an elevational view of an exemplary inner core for the annuloplasty band of FIGS. 3A-3D. FIG. [Figure 5C] 3E is an elevational view of an exemplary inner core for the annuloplasty band of FIGS. 3A-3D. FIG. [Figure 6A] 5B is a cross-sectional view of the inner core taken along the corresponding cross-sectional line of FIG. 5A. [Figure 6B] 5B is a cross-sectional view of the inner core taken along the corresponding cross-sectional line of FIG. 5A. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present application discloses an asymmetric mitral annuloplasty band that avoids adjacent aortic valve structures and provides better protection against dehiscence along the muscular mitral annulus. The term "band" is used herein because the implant is a discontinuous ring. However, such implants may also be referred to as "rings" depending on the context. Indeed, the bands disclosed herein define a shape that encircles most of the mitral annulus and thus largely traces the ring shape. A complete ring shape may be constructed, or indeed, the shape of the band may be defined by imagining a shape extending between and connecting the free ends. For example, a preferred planar shape of the disclosed band is kidney- or D-shaped to follow the circumferential shape of a normal mitral annulus. Thus, the terms "band" and "ring" are synonymous, and the disclosed bands or rings are simply discontinuous, having two free ends.

[0032] The term "axis," as used with reference to the illustrated annuloplasty bands and other non-circular or non-planar bands, refers to a line that passes approximately through the circumferential center of gravity of the band or ring when viewed in a plan view. The "axial" or "axial" direction can also be viewed as parallel to the average direction of blood flow within the valve orifice, and thus within the band when implanted in the valve orifice. In other words, the implanted mitral valve band or mitral valve ring is oriented about a central flow axis that lies along the average direction of blood flow from the left atrium to the left ventricle through the mitral valve annulus.

[0033] FIG. 1 is a plan view of the mitral valve, with the posterior facing downward and the anterior facing upward. In a healthy heart, the annulus of the mitral valve MV assumes an anatomical shape and tension such that, under peak systolic or systolic pressure, the posterior leaflet PL and the anterior leaflet AL join at the flow orifice to form a tight junction, as shown in FIG. 1. The annulus of the mitral valve MV has a posterior surface with the posterior leaflet PL and an anterior surface with the anterior leaflet AL. The locations where the leaflets meet on the opposing medial and lateral sides of the annulus are also referred to as leaflet commissures: the anterior commissure (or, more precisely, the anteromedial commissure) AC and the posterior commissure (or posterolateral commissure) PC. The posterior leaflet is divided into three scallops, or cusps, sometimes identified as P1, P2, and P3, beginning at the anterior commissure and continuing counterclockwise to the posterior commissure. The posterior sails P1, P2, and P3 define a distinctive arc around the circumference of the posterior annulus, which may vary depending on various factors, such as the actual measurements of the posterior mitral valve sails and surgeon preference. Generally, however, the long axis 22 of the mitral annulus intersects both the first posterior sail P1 and the third posterior sail P3 at approximately the commissures AC and PC, and the short axis 24 intersects and generally bisects the central posterior sail P2. The anterior leaflet is also characterized by sails or regions designated A1, A2, and A3, as shown in FIG. 1.

[0034] The anterior leaflet (AL) of the mitral valve is attached to the fibrous portion (FA) of the mitral annulus, which forms approximately one-third of the total circumference of the annulus. The muscular portion of the annulus forms the remainder of the annulus, to which the posterior leaflet (PL) is attached. The anterior fibrous annulus (FA), whose two ends are called the fibrous trigone (T), forms part of the central fibrous body of the heart. The anterior commissure (AC) and posterior commissure (PC) are located immediately posterior to each fibrous trigone.

[0035] The fibrous mitral annulus FA contacts or is adjacent to the aortic valve AV, particularly the left coronary sinus LCS and non-coronary sinus NCS. Because the central fibrous body is fairly resistant to stretch, most of the dilation of the mitral annulus occurs in the posterior two-thirds of the annulus, or around the muscular annulus.

[0036] In a preferred embodiment, the annuloplasty band disclosed herein comprises discontinuous rings defining a kidney- or D-shaped configuration with a substantially complete posterior segment centered about the minor axis of the band. Additionally, the annuloplasty band defines two anterior segments having opposing free ends, the anterior segments extending unequal lengths from the posterior segment. The unequal lengths of the two anterior segments of the band create an asymmetry that is unbalanced toward the posterior commissure.

[0037] To better define the asymmetric annuloplasty band disclosed herein, FIG. 1 illustrates a circumferential span 30 around the mitral valve annulus and roughly illustrates the range of band lengths. More specifically, the band's maximum length extends counterclockwise (CCW) from a radial angular position 32 of the anterior commissure AC to a radial angular position 34 above the posterior commissure PC within the fibrous mitral annulus. It will be appreciated that the asymmetric band extends around the mitral valve annulus at a span that avoids the adjacent aortic valve structures of the left coronary sinus LCS and non-coronary sinus NCS. As illustrated, the aortic valve AV is believed to be located slightly off the short axis 24. Additionally, the portion of the band extending around the right posterior commissure PC reinforces the region and inhibits dehiscence or suture pullout in that region. Generally, the band extends circumferentially around the posterior leaflet PL and a short distance beyond the posterior commissure PC around the anterior leaflet AL.

[0038] To help better define this span, clock positions can be assigned to the major and minor axes 22, 24 of the mitral valve MV. That is, the minor superior-inferior axis 24 extends between and defines the 12:00 and 6:00 positions, and the major left-right axis 22 extends between and defines the 3:00 and 9:00 positions. Using this nomenclature, the longest band illustrated in FIG. 1 extends between approximately the 9:00 radial position 32 and the 1:00 radial position 34. Of course, these geometries can also be expressed as percentages of a continuous ring or in degrees, in which case the maximum span 30 described above is approximately 67% around the mitral annulus, or approximately 240°.

[0039] Radial positions 32 and 34 correspond to the free ends of the bands. Each free end may be independently shortened, as indicated by secondary radial positions 36 and 38. Radial position 36 is approximately the 8:30 position, and radial position 38 is approximately the 1:30 position. As a result, the shortest band may extend approximately 58% or approximately 210° around the mitral annulus. Intermediate bands, with one end shortened and the other unshortened, are also contemplated, corresponding to a band extending approximately 62% or approximately 225° around the mitral annulus.

[0040] FIG. 2 illustrates the mitral valve and anatomical landmarks with an exemplary annuloplasty band 40 secured to the mitral valve. The band 40 is shaped and sized to avoid adjacent aortic valve (AV) structures, providing better protection against dehiscence along the muscular mitral annulus. When implanted, the band 40 is asymmetric in that it extends around one side of the mitral annulus more than the other. That is, the band 40 is asymmetric with respect to the minor axis 24 of the annulus. Looking down on the mitral valve as in FIG. 2, the minor axis 24 in the superior-inferior direction extends through the midpoint of both leaflets AL and PL. The annuloplasty band 40 is discontinuous, comprising a midsection 42 and two free ends 44a, 44b, one on either side of the minor axis 24. Band 40 extends asymmetrically around the mitral valve annulus in a counterclockwise direction toward the posterior commissure PC more than in a clockwise direction toward the anterior commissure AC, resulting in a greater or longer circumferential length to the right than to the left. In other words, the asymmetrical orientation of implanted band 40 is rotated counterclockwise (CCW) around the mitral valve annulus from a symmetrical orientation such that the center of the band's circumference (located approximately at numeral 46) is located counterclockwise from minor axis 24.

[0041] As shown in FIGS. 3A-3D , the exemplary annuloplasty band 40 has a gentle upward rise or arcuate shape 50 at its midsection 42 along a vertical axis 48 centered about the minor axis 24. (The vertical axis 48 is perpendicular to both the major axis 22 and the minor axis 24 and extends through their intersection.) This arcuate shape 50 tapers off on either side of the minor axis 24 toward a low point around the ring generally on the major axis 22. Because the first free end 44 a is located on or adjacent to the major axis 22, the first free end 44 also roughly corresponds to the first of the low points. A second low point 52 occurs at the midsection 42 of the band along the major axis 22, opposite the first free end 44 a. The band 40 then rises from the second low point 52 toward the second free end 44 b. If band 40 were continuous, as shown by dashed extension 54 in Figure 3C, band 40 would define a saddle shape with both anterior and posterior sections bowing upward (convex upward) and both sides curving downward (convex downward) across longitudinal axis 22. Of course, the discussion herein refers to the relative orientation, with "up" corresponding to the left atrium and "down" corresponding to the left ventricle, such that blood flow is downward through the annulus.

[0042] As shown in the bottom views of Figures 2, 3A, and 3C, the upwardly directed arcuate portion 50 of the annuloplasty band 40 is centered about the minor axis 24 such that the length of the band on either side of the high point of the arc is different. Specifically, a first span 60 extending counterclockwise (CCW) from the high point of the arcuate portion 50 on the minor axis 24 is longer than a second span 62 extending clockwise (CW) (these directions are reversed in the bottom view of Figure 3C). As noted above, the spans of the band 40 on each side of the minor axis 24 are different, with the first span 60 extending beyond the posterior commissure PC of the mitral valve annulus and the second span 62 extending approximately to or slightly shorter than the anterior commissure AC. Using the above expression, first span 60 extends CCW from minor axis 24 to a position at approximately 1:00, i.e., approximately 42% (150°) around the mitral annulus, while second span 62 extends CW from minor axis 24 to a position at approximately 9:00, i.e., approximately 25% (90°) around the mitral annulus. Furthermore, first span 60 and second span 62 may be independently somewhat shorter, as shown by radial lines 36 and 38 in FIG. 1 .

[0043] 4A and 4B are cross-sectional views of the annuloplasty band 40 taken along the corresponding cross-sectional line of FIG. 3B. In a preferred embodiment, the band configuration includes a relatively rigid or semi-rigid inner core 70 surrounded by a suture-passable surface, which may include an elastomeric sleeve 72 closely surrounding the core, and a fibrous outer cover 74, such as a polyethylene terephthalate (PET) fabric cover. In a preferred embodiment, the elastomeric sleeve 72 may be silicone rubber and is shaped to have an outwardly extending flange 76 to facilitate suturing of the band 40 to the mitral valve annulus. The band 40 may be secured to the inner ledge of the mitral valve annulus with sutures, staples, or other such devices. In a typical procedure, an array of sutures is anchored through the annulus and then threaded around the band 40 at corresponding locations, after which the band is parachuted down to seat the suture array in the annulus before the sutures are tied.

[0044] 5A-5C illustrate an exemplary inner core 70 for an annuloplasty band 40. The core 70 can comprise a variety of materials and cross-sectional shapes, and is shown rectangular in the illustrated embodiment. As shown in cross-sectional views 4A / 6A and 4B / 6B taken at different locations of the band 40 and core 70, the core is desirably thicker in the midsection than toward the free ends 80a, 80b. This provides some flexibility near the free ends 44a, 44b of the band 40 to help avoid distraction or suture pull-out.

[0045] The annuloplasty bands of the present invention are "generally rigid" in that they resist distortion when subjected to stresses imposed by the mitral annulus of the human heart during surgery. In this sense, "distortion" refers to substantial and permanent deformation from a predetermined or manufactured shape. Several "generally rigid" materials can be utilized for the inner core of the band to perform this function, including various biocompatible polymers, metals, alloys, combinations, or composites thereof. For example, certain polyesters can be used that resist distortion and rapid degradation within the body portion (although slower degrading materials may initially provide the necessary support). In preferred embodiments, at least the inner core or body portion of the annuloplasty bands of the present invention is comprised of a suitable metal, such as a cobalt-chromium (Co-Cr) alloy (e.g., ELGILOY® Co-Cr alloy manufactured by Elgiloy L.P., Elgin, IL, USA), titanium or a titanium alloy (e.g., titanium-6-4, containing approximately 6% aluminum and approximately 4% vanadium by weight), stainless steel, nitinol, or a combination thereof.

[0046] The core or band body may be a single piece, may include multiple concentric bands or other cooperating elements held together, or any combination thereof. Single-piece core embodiments include those with square / rectangular cross sections, as illustrated in Figures 6A and 6B, as well as cores having other shapes, such as convex polygons, circles, or ellipses. Other core embodiments include at least one channel, such as a C-shaped or H-shaped cross section. As illustrated in Figures 6A and 6B, the cross-sectional shape can vary along the length of the core. Thus, in some cores, at least one portion (e.g., along the midsection) includes a channel, while other portions (e.g., one or both ends) do not.

[0047] Embodiments in which the core comprises bands include cores in which the bands are radially, concentrically, and / or axially stacked. The flexibility or stiffness of one or more selected portions of such a core can be adjusted, for example, by varying the number of bands in the portion, varying the thickness of at least one band in the portion, incorporating at least one band comprising a different material, or any combination thereof. Some embodiments include a spacer, such as a polymeric spacer and / or an elastomeric spacer, between at least one pair of adjacent bands. Another embodiment of a multi-piece core includes a braided core, which is made up of multiple wires, strands, and / or braids.

[0048] The annuloplasty bands of the present invention are also particularly suited to correcting certain medical conditions. That is, the present invention contemplates a set of bands defined by band bodies in which the shape of the band bodies varies proportionately with increasing nominal orifice size of the band bodies in the set. Orifice size generally refers to the nominal length across the longitudinal axis of the band body, although some rings or bands deviate from this usage. Typically, annuloplasty rings and annuloplasty bands have orifice sizes measured across their longitudinal axes in even-numbered millimeter increments (e.g., 24 mm, 26 mm, etc., up to about 40 mm). Other sizing schemes are also possible, such as odd-numbered millimeter increments, every millimeter increments, or combinations thereof (e.g., every millimeter up to a certain size and then increasing by even millimeters beyond that size). Such rings have distinctive packaging so that they are labeled with specific sizes. The change in band shape depends on the medical condition to be corrected. For example, if the condition results in mitral valve regurgitation, a band set with increasing circularity as the band size increases may be beneficial. It is important to understand that this band set is formed with a band body that is "generally rigid" during manufacturing and is not easily manipulated. One example is a band core formed with a band of Elgiloy® Co-Cr alloy. It should also be noted that the holder for such annuloplasty bands has a peripheral shape that conforms to the optimal size of the band.

[0049] Some sets of annuloplasty bands include progressively sized bands (i.e., at least one dimension does not increase or decrease linearly with the labeled band size). As noted above, the labeled sizes are with respect to major axis length, and therefore, this progression, or nonlinearity, is described with respect to major axis length unless otherwise noted. Examples of progressive size dimensions in embodiments of a set of bands include minor axis length and saddle height or degree of saddle. Another variable affected by progressivity is the flexibility of at least a portion of the band. Some sets include bands with a combination of progressive dimensions (e.g., minor axis length and saddle height).

[0050] In some sets, every band in the set has progressive sizes along at least one dimension. In some sets, the progressive sizes are applied incrementally, for example, to a subset or range of band sizes, rather than to each individual band. For example, some sets include a first range of band sizes in which the dimension increases or decreases proportionally with size, and a second range of band sizes in which the dimension also increases or decreases proportionally with size, but at a different ratio between the first and second ranges. In some sets, the first range of sizes does not have progressive sizes (e.g., small bands), but the second range of sizes does have progressive sizes (e.g., large bands).

[0051] As noted above, in some sets, the ratio of minor axis 24 to major axis 22 changes with size. In some embodiments, this aspect ratio increases with labeled size. For example, while some bands described herein may be defined as portions of a D-shape as shown in the drawings, bands sized about 36 mm and above become more rounded. As a result, in some embodiments, at larger sizes, the curvature of the band becomes more symmetrical about major axis 22 in plan view, at least on the long side (see FIG. 2).

[0052] In another example, the band set has a non-linear increasing saddle profile with increasing size, i.e., a preferred band set has a relatively flat saddle (with a small upward bow) for bands smaller than about 30 mm, a constant gradual saddle shape for bands between about 24 and 30 mm, while the larger bands between about 36 and 40 mm have a more pronounced saddle shape.

[0053] In other band sets, the saddle increases proportionally with size in the smaller sizes and then increases gradually as the sizes increase. Variations include an intermediate range where the saddle increases gradually, but at a more moderate rate than in the larger sizes.

[0054] While the above is a complete description of the preferred embodiment of the present invention, it will be apparent that various alternatives, modifications and equivalents may be used, and other modifications may be practiced within the scope of the appended claims. [Explanation of symbols]

[0055] 22 Long axis 24 Short axis 30 perimeter span 40 Mitral annuloplasty band 42 Mid Section 44a first free end 44b second free end 48 Vertical Axis 50 Arcuate part 60 First Span 62 Second Span 70 inner core 72 Elastomer sleeve 74 Outer cover 76 flange 80a free end 80b free end

Claims

1. 1. An asymmetric mitral annuloplasty band adapted to be implanted against a native mitral valve annulus, the mitral valve annulus having a posterior surface with a posterior leaflet and an anterior surface with an anterior leaflet, the mitral valve annulus generally defining a D- or kidney-shaped shape when viewed from the inflow side of the mitral valve annulus, with a midpoint of both the anterior and posterior surfaces defining a saddle shape rising toward the left atrium, the anterior surface being more nearly straight than the posterior surface and the posterior surface being more rounded than the anterior surface, and intersecting the mitral valve annulus and forming a saddle shape a minor axis extending through the mitral valve annulus between the midpoint of the anterior surface and the midpoint of the posterior surface is shorter than a major axis that is perpendicular to the minor axis, intersects the mitral valve annulus, and extends through the mitral valve annulus; an anterior commissure and a posterior commissure are located on the mitral valve annulus at two junctions between two leaflets; the anterior commissure is located clockwise from the midpoint of the posterior leaflet, and the posterior commissure is located counterclockwise from the midpoint of the posterior leaflet; an elongated, discontinuous body portion including a rigid or semi-rigid inner core surrounded by a suture-passable surface, the body portion defining an asymmetric shape in a top view, the body portion having a posterior section that generally conforms to the plan view of the entire posterior surface of the mitral valve annulus when the annuloplasty band is implanted, the posterior section being symmetrical about the minor axis, the body portion terminating at a first free end corresponding to the anterior commissure of the mitral valve annulus and at an opposite end corresponding to the major axis corresponding to the posterior commissure of the mitral valve annulus. an annulus extending further toward the anterior surface beyond its intersection with the annulus and terminating at a second free end, defining a gap between the first and second free ends; the body portion having a partial saddle shape with a first high point in an upwardly arcuate portion centered at the midpoint of the posterior section, two low points located approximately at the intersection of the long axis and the mitral valve annulus when the annulus is implanted, and a second high point at the second free end.

2. The asymmetric annuloplasty band of claim 1 , wherein the entire circumferential span of the body portion encircles a majority of the mitral valve annulus.

3. 3. The asymmetric annuloplasty band of claim 2, wherein the entire circumferential span of the body portion extends 67% around the mitral valve annulus.

4. 3. The asymmetric annuloplasty band of claim 2, wherein a circumferential span of the portion of the body extends from a midpoint of the posterior section to the second free end between 37% and 42% around the mitral valve annulus.

5. 2. The asymmetric annuloplasty band of claim 1, wherein a circumferential span of the portion of the body extends between 37% and 42% around the mitral valve annulus from a midpoint of the posterior section to the second free end.

6. 2. The asymmetric annuloplasty band of claim 1, wherein the first free end is adapted to be implanted adjacent the anterior commissure and the body portion extends in a counterclockwise direction within the anterior surface to the second free end.

7. 2. The asymmetric annuloplasty band of claim 1, wherein the rigid or semi-rigid inner core is rectangular and has a thickness in a middle portion thereof greater than in portions proximate the first and second free ends.

8. 8. The asymmetric annuloplasty band of claim 7, wherein the rigid or semi-rigid inner core is made of a metal selected from the group consisting of cobalt-chromium (Co-Cr) alloy, titanium, a titanium alloy, stainless steel, nitinol, and combinations thereof.

9. The asymmetric annuloplasty band of claim 1 , wherein the first free end is configured to be implanted in the mitral valve annulus on a longitudinal axis.

10. 1. An asymmetric mitral annuloplasty band adapted to be implanted against a native mitral valve annulus, the mitral valve annulus having a posterior surface with a posterior leaflet and an anterior surface with an anterior leaflet, the mitral valve annulus generally defining a D- or kidney-shaped shape when viewed from the inflow side of the mitral valve annulus, with a midpoint of both the anterior and posterior surfaces defining a saddle shape rising toward the left atrium, the anterior surface being more nearly straight than the posterior surface and the posterior surface being more rounded than the anterior surface, and intersecting the mitral valve annulus and forming a saddle shape a minor axis extending through the mitral valve annulus between the midpoint of the anterior surface and the midpoint of the posterior surface is shorter than a major axis that is perpendicular to the minor axis, intersects the mitral valve annulus, and extends through the mitral valve annulus; an anterior commissure and a posterior commissure are located on the mitral valve annulus at two junctions between two leaflets; the anterior commissure is located clockwise from the midpoint of the posterior leaflet, and the posterior commissure is located counterclockwise from the midpoint of the posterior leaflet; a discontinuous elongated body portion including a rigid or semi-rigid inner core surrounded by a suture-passable surface, the body portion defining an asymmetric shape in a top view and having a posterior section that generally conforms to the plan view of the entire posterior surface of the mitral valve annulus when the annuloplasty band is implanted, the body portion extending in a clockwise direction along a first span from a midpoint corresponding to a center of the posterior surface to a first free end corresponding to an anterior commissure of the mitral valve annulus, and the body portion extending in a clockwise direction along a second span from the midpoint to a second free end.

1. An asymmetric mitral annuloplasty band, comprising: a body portion extending counterclockwise along a longitudinal axis past the posterior commissure of the mitral valve annulus, defining a gap between the first free end and the second free end; a body portion having a first high point at an upwardly arcuate portion corresponding to a bulge on the posterior surface of the mitral valve annulus; two low points located approximately at the intersection of the longitudinal axis and the mitral valve annulus when the mitral annuloplasty band is implanted; and a second high point at the second free end.

11. The asymmetric annuloplasty band of claim 10 , wherein the entire circumferential span of the body portion encircles a majority of the mitral valve annulus.

12. 12. The asymmetric annuloplasty band of claim 11, wherein the entire circumferential span of the body portion extends 67% around the mitral valve annulus.

13. 12. The asymmetric annuloplasty band of claim 11, wherein a circumferential span of the portion of the body extends from the midpoint to the second free end between 37-42% around the mitral valve annulus.

14. 11. The asymmetric annuloplasty band of claim 10, wherein a circumferential span of the portion of the body extends from the midpoint to the second free end between 37-42% around the mitral valve annulus.

15. 11. The asymmetric annuloplasty band of claim 10, wherein the first free end is adapted to be implanted adjacent the anterior commissure and the body portion extends in a counterclockwise direction within the anterior surface to the second free end.

16. 11. The asymmetric annuloplasty band of claim 10, wherein the rigid or semi-rigid inner core is rectangular and is thicker at a middle portion than at portions near the first and second free ends.

17. 17. The asymmetric annuloplasty band of claim 16, wherein the rigid or semi-rigid inner core is made of a metal selected from the group consisting of cobalt-chromium (Co-Cr) alloy, titanium, a titanium alloy, stainless steel, nitinol, and combinations thereof.

18. The asymmetric annuloplasty band of claim 10 , wherein the first free end is configured to be implanted into the mitral valve annulus on a longitudinal axis.

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