Annuloplasty ring with cut zone

[0002] The present invention relates to a prosthetic support used to correct defects in a heart valve of a heart. More specifically, the present invention relates to an annuloplasty ring prosthesis for implantation around a heart valve.

[0003] Annuloplasty rings are used to provide support to surgically corrected defects in natural valves of a patient's heart. The valves in the human heart, and in particular the mitral and tricuspid valves, include valve cusps or leaflets which are attached to the wall of the heart by fibrous chords. However, defects in the heart valve and surrounding tissue can reduce the efficiency of the heart in pumping blood. For example, if the annulus of a heart valve dilates due to disease, the valve cusps cannot completely close. This allows blood to regurgitate through the valve and greatly reduces the efficiency of the heart.

[0004] One technique of repairing a defective natural heart valve is to completely replace the valve. Valve replacements include both mechanical heart valves and bioprosthetic heart valves. However, such surgery requires the natural valve to be excised. In many instances it would be preferable to retain the natural valve by repairing the valve. For a number of reasons, it is desirable to retain the natural heart valve if possible.

[0005] A native valve repair procedure utilizing an annuloplasty ring is a desirable alternative to replacement valves in that the repair procedure does not require excision of the natural valve. Various types of annuloplasty rings are described in the prior art including rigid rings and flexible rings. For example, U.S. Pat. No. 5,061,277, issued Oct. 29, 1991 to Carpentier et al., entitled “FLEXIBLE CARDIAC VALVULAR SUPPORT PROSTHESIS” is an example of one such annuloplasty ring. Flexible annuloplasty rings allow the heart to follow a more physiological movement during systole and diastole. Additionally, the native mitral annulus is not a flat plane, and the anterior portion of the mitral annulus is curved. Such flexibility is particularly beneficial when the heart is operating at higher capacities. Traditionally, annuloplasty rings have a generally full annular configuration. The full annuloplasty ring is sutured to the tissue annulus of the natural heart valve. The ring provides support to the valve annulus or repaired valve to thereby maintain the shape of the repaired heart valve by preventing dilation of the annulus.

[0006] Recently, annuloplasty rings have been designed with a partial annular configuration. One such design is described in U.S. Pat. No. 5,041,130. Such a partial annular configuration may allow limited expansion of the natural annulus during diastole. The partial annular configuration has no anterior portion which allows the natural mitral annulus shape to be preserved in this area and to function naturally.

[0007] The anterior portion of the mitral annulus does not dilate with disease processes. Therefore, there is no need for the annuloplasty device to address this area. Not placing sutures in the anterior portion of the annulus eliminates the possibility of deforming or injuring, with sutures, the aortic valve leaflets which are in fibrous continuity with the anterior portion of the mitral valve. The decision to support the anterior portion of the annulus must be made by the surgeon on a case by case basis, and is frequently not apparent until the natural valve and surrounding cardiac anatomy is visibly inspected during surgery. Likewise, a partial ring can be used to repair the tricuspid valve to eliminate any negative effects of placing the suture in or near the AV-node.

[0008] The present invention provides an annuloplasty ring which may be implanted either as a full annular ring or as a partial ring. The annuloplasty ring includes an elongated main body having a generally partial annular configuration which extends between a first end and a second end. An elongated secondary body includes a first end and a second end extending between respective first and second ends of the elongated main body. In one embodiment of the invention, the elongated main body and the elongated secondary body are formed of flexible materials. A cut zone couples the first end of the main body to the first end of the secondary body. The cut zone may be severed, thereby forming an annuloplasty ring having a generally partial annular configuration. However, if the zone is not severed, the annuloplasty ring may be employed with a generally full annular configuration. The cut zone may extend through the entire length of the secondary body thereby forming a single elongated cut zone. Further, the cut zone may extend into the elongated main body.

[0009] FIG. 1 is a top plan view of an annuloplasty ring in accordance with the present invention having a full annular configuration.

[0010] FIG. 2 is a top plan view of the annuloplasty ring of FIG. 1 having a portion removed thereby forming a partial annular configuration.

[0011] FIG. 3A is a cross-sectional view taken along the line labeled 3A—3A in FIG. 1 of a main body portion of the annuloplasty ring.

[0012] FIG. 3B is a cross-sectional view taken along the line labeled 3B—3B of FIG. 1 of a secondary body of the annuloplasty ring.

[0013] FIG. 4 is a top plan view of a portion of the annuloplasty ring showing a suture used to form a cut zone.

[0014] FIG. 5 is a diagram of a suture knot used with the suture of FIG. 4.

[0015] FIGS. 6A and 6B are side plan views showing steps in the manufacture of the annuloplasty ring of FIG. 1.

[0016] The present invention includes an annuloplasty ring which selectively provides either a full annular or ‘D’ shape geometry or a partial annular or ‘C’ shape geometry ring. Annuloplasty rings in accordance with the present invention may be modified by a surgeon after the surgeon performs a visual inspection of the native heart valve. Further, the surgeon may select the circumference of the partial annular configuration to thereby optimize the circumference of the annuloplasty ring for a particular patient's valve annulus.

[0017] FIG. 1 is a top plan view of an annuloplasty ring 10 in accordance with one embodiment of the present invention. Annuloplasty ring 10 has a full annular configuration. Note that as used herein, a full or ‘D’ shaped configuration is intended to refer to any shape annuloplasty ring which provides a complete annulus. Further, as used herein a partial or ‘C’ shape annuloplasty ring refers to any annuloplasty ring which provides only a partially complete annulus.

[0018] Annuloplasty ring 10 includes an elongated main body 12 having a generally partial annular configuration which extends between a first cut zone or cut zone marker 14 and a second cut zone or cut zone marker 16. An elongated secondary body 18 extends between a first marker 14 and a second marker 16. The elongated secondary body 18 completes the annulus of annuloplasty ring 10 to thereby form a full ring. Cut zone markers 14 and 16 identify the ends of the elongated main body 12.

[0019] Annuloplasty ring 10 is formed from an outer layer 36 which is typically a fabric, such as polyester, shaped into tubular form creating an inner layer 60 (FIG. 3). Both layers are stitched together using a suture, which is indicated generally at stitching 32 and 34. Stitching 34 and internal stitching 53 are formed in a series of individual knots in secondary body 18. In some embodiments, the knots may extend through the secondary body 18 and partially into main body 12. Stitches 32 and 52 are positioned to maintain the inner layer 60 and outer layer 36 around a core (not shown in FIG. 1) of ring 10. However, in accordance with one aspect of the present invention, if secondary body 18 is severed within the defined markers 14 and 16, the knotting of stitches 34 and 53 prevents the suture and the outer layer 36 and inner layer 60 from fraying. Thus, the knots of stitches 34 and 53 act as a body retaining member to maintain the integrity of the outer layer 36 and inner layer 60.

[0020] FIG. 2 is a top plan view of annuloplasty ring 10 after the cuts have been made between or at first marker 14 and second marker 16 thereby removing a portion 40 of the elongated secondary body 18. The cuts form ends 20, 22, 24, and 26. Further, stitching 34 includes relatively long stitches which are clearly visible and provide an additional cut zone markings.

[0021] In accordance with the present invention, upon removal of portion 40 ends 20, 22, 24 and 26 are prevented from unraveling or fraying by knotted stitches 34 and 53. Any appropriate knotting technique may be used, for example, knots which are typically used by surgeons to secure sutures, or a simple cinch knot. Further, any type of body retaining member may be employed to maintain the integrity of the body of annuloplasty ring 10 and prevent fraying of the body or fraying of the suture, such as staples, adhesives, ultrasonics welding, etc.

[0022] FIG. 3A is a side cross-sectional view of annuloplasty ring 10 taken along the line labeled 3A—3A in FIG. 1. As shown in FIG. 3A, in one embodiment, main body 12 includes a core 50 covered by outer layer 36. Typically, core 50 comprises silicone or other biocompatible material, such as a metal, like stainless steel, or plastic such ultra high molecular weight polyethylene and outer layer 36 comprises a fabric sheath made of polyester, PTFE or other materials such as pericardial tissue. Layer 36 is secured by sutures 52 and 54. FIG. 3B is a cross-sectional view of secondary body 18 taken along the line labeled 3B—3B of FIG. 1. As shown in FIG. 3B, core 50 preferably does not extend into secondary body 18. Core 50 preferably does not extend beyond markers 14 and 16 of main body 12.

[0023] During surgery, the surgeon can select to use the full annular configuration of annuloplasty ring shown in FIG. 1 or the partial annular configuration shown in FIG. 2. If the surgeon decides that a partial annular configuration annuloplasty ring is desirable, a scalpel or other sharp instrument or a cauterizing device may be used to cut the annuloplasty ring at the markers 14 and 16, or at any point(s) therebetween. Markers 14 and 16 provide a visible indicator for the surgeon when severing the annuloplasty ring as well as enable proper sizing of the ring within the annulus. In one embodiment, markers 14 and 16 are formed by wrapping a suture around the ring 10. When forming the partial annular ring of FIG. 2, portion 40 may be discarded and the remaining partial annular configuration implanted around the posterior leaflet annulus of the patient's heart.

[0024] FIG. 4 is a top plan view of inner fabric layer 60 showing suture 52 and inside knots 53. Arrows provided in FIG. 4 illustrate the direction of suturing. In one preferred embodiment, knot 53 comprises a double cinch knot as shown in FIG. 5. Between points 1 and 2 shown in FIG. 4, suture 52 extends under layer 60. From point 2 to point 3, suture 52 extends over layer 60 and across the gap formed between the two sides of layer 60. From point 3 to point 4, suture 52 is threaded under layer 60 and over from point 4 to point 5. Knot 53 is formed at point 5 and suture 52 is brought back across the fabric to the opposite side of layer 60 and the process is repeated.

[0025] FIGS. 6A and 6B are side plan views showing steps in forming stitches 34. As shown in FIG. 6A, the fabric of body 18 is brought together and suture 54 is threaded through the fabric using needle 70. As shown in FIG. 6B, suture 54 is brought back around through both fabric layers and under itself to form stitch 34. Preferably, this is done in a manner to leave a relatively long portion of suture 54 exposed to thereby mark the cut zone. Further, as every stitch includes a knot, the cut zone will not fray if it is severed.

[0026] In addition to markings 14 and 16, elongated stitches 34 are also visible along the length of secondary body 18 and provide an indication of the cut zone region.

[0027] Thus, the present invention provides a single annuloplasty ring which may be selectively configured either as a full annuloplasty ring or as a partial annuloplasty ring. Another feature of the present invention is that when the partial configuration is selected by the surgeon, the surgeon has the ability to select the length of the outer circumference. Specifically, a surgeon may determine that only a small portion of the secondary body should be removed leaving a partial annular configuration that provides an outer circumference of any desired length, including an outer circumference which is almost completely closed. Furthermore, in yet another aspect of the present invention, the secondary body may be severed at a single location.

[0028] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For example, the core can extend into the cut zone and the ring may be a rigid ring and is not limited to the flexible material or fabrics set forth herein.