AU2002324750A1 - Self-molding annuloplasty ring - Google Patents

Description

SELF-MOLDING ANNULOPLASTY RING AND METHOD OF USE

BACKGROUND OF THE INVENTION

[0001] The human heart is hollow muscular organ having four pumping chambers separated by four heart valves. The mitral and tricuspid valves, present at the left and right atrio-ventricular junctions, open and close in response to a pressure gradient during each cardiac cycle of relaxation and contraction to control the flow of blood to a particular region of the heart.

[0002] These valves are comprised of a dense fibrous ring known as the annulus, leaflets or cusps attached to the annulus, and a complex of chordae tendineae and papillary muscles securing the leaflets. The size of the leaflets or cusps is such that when the heart contracts the resulting increased blood pressure formed within the ventricular cavity forces the leaflets towards the arterial cavity. As a result, the leaflets or cusps come in apposition to each other thereby closing the atrio- ventricular passage.

[0003] Natural defects and heart disease are common causes of valvular dysfunction within the heart of a patient. One common example of valvular dysfunction occurs when the annulus becomes excessively dilated or the valve geometry results in effective valve closure, which results in regurgitation. Due to the increased diameter of the annulus, the leaflets or cusps fail to meet during systolic contraction, thereby resulting in the regurgitation of blood during ventricular contractions. As such, sufficient back pressure exists within the chambers of the heart capable of forcing some blood flow to traverse the atrio-ventricular junction from the ventricle to the atria.

[0004] One manner of repairing this problem involves surgically implanting a prosthetic ring (i.e. "annulolasty ring") about the dilated annulus, thereby restoring the annulus to the normal size and shape and allowing the valve leaflets to function normally. Commonly, a surgeon positions the annuloplasty ring near the valve annulus and sutures the device in place.

[0005] One approach to correcting or remodeling the valve annulus has required the implantation of a rigid annuloplasty ring. Typically, a annuloplasty ring having the desired internal diameter is positioned near the heart valve and sutured in place. As a result, the diameter of the valve is reduced to the diameter of the annuloplasty ring. This procedure utilizing current annuloplasty rings has several shortcomings. For example, the tissue comprising the heart, particularly in the area of the heart valves, is flexible. The implantation of a rigid annuloplasty ring restricts the natural flexibility of this tissue, and may impact the heart function. Also, the dilated annulus is substantially larger in diameter than the annuloplasty ring, thereby making the implantation surgery unnecessarily time consuming. The surgeon is required to position the prosthesis near a portion of the tissue and suture the ring in place. Thereafter, the opposing tissue is forced to engage the ring and is attached to the annuloplasty ring with sutures. Consequently, the sutures may be under different stress loads, and could result in an increased risk of ring dehiscence.

[0006] Thus, there is a need for a flexible annuloplasty prosthesis and implantation device which enables a surgeon to precisely position and apply an annulplasty ring to the dilated valve annulus.

SUMMARY OF THE INVENTION

[0007] The present invention solves the aforementioned problems in that the resilient annuloplasty ring of the present invention may be stretched to the diameter of the dilated valve annulus prior to implantation, thereby simplifying the implantation process. In addition, the contractive force of the resilient annuloplasty ring of the present invention may controllably reduce the diameter of an incompetent dilated valve annulus to more competent diameter. Those skilled in the art will appreciate the present invention is easy to manufacture and may be manufactured from a plurality of materials.

[0008] The annuloplasty ring of the present invention comprises a resilient inner sizing member positioned within a resilient outer attachment sheath. The resilient inner sizing member applies a contractive force to the incompetent annulus tissue. The resilient outer attachment sheath permits the surgeon to attach the device to the annulus tissue in a plurality of manners including suturing and stapling. Those skilled in the art will appreciate the annuloplasty ring of the present invention may be manufactured from a plurality of biologically compatible materials having sufficient resiliency to permit stretching during implantation and having sufficient contractive force to permit a reduction in the diameter of the incompetent valve annulus.

[0009] The present invention further discloses an alternate embodiment of the self molding annuloplasty ring. The present embodiment comprises an resilient inner sizing member positioned within a resilient outer attachment sheath, the ring having a plurality of attachment member positioned thereon. Those skilled in the art will appreciate the attachment members may comprise a plurality of devices, including, for example, needles, barbs, or hooks. In addition, the attachment members may be manufactured from a plurality of materials, including, without limitation, stainless steel, titanium, and Nitinol. [0010] In yet another embodiment of the present invention, a self molding annuloplasty ring having a predetermined contracted diameter is disclosed. The present embodiment comprises a resilient inner sizing member positioned within a series of individual sizing supports. A resilient outer attachment sheath is positioned on the exterior of the sizing supports. The present embodiment permits the surgeon to predetermine the inner diameter of a repaired valve annulus, thereby rendering an incompetent valve competent. Those skilled in the art will appreciate the sizing support members may be manufactured from a plurality of biologically compatible materials, including, without limitation, plastic and elastomer.

[0011] Other objects, features, and advantages of the present invention will become apparent from a consideration of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The apparatus of the present invention will be explained in more detail by way of the accompanying drawings, wherein:

[0013] Figure 1 shows a top sectional view of the mitral and tricuspid valves and valve annuli within a heart;

[0014] Figure 2A shows a side view of the annuloplasty ring of the present invention;

[0015] Figure 2B shows a top view of the annuloplasty ring of the present invention;

[0016] Figure 2C shows a cross sectional view of the annuloplasty ring of the present invention; [0017] Figure 2D shows an alternate embodiment of the annuloplasty ring of the present invention having a support member positioned therein;

[0018] Figure 2E shows a perspective view of the annuloplasty ring of the present invention;

[0019] Figure 3 shows a top sectional view of the annuloplasty ring of the present invention positioned within the valve annulus of the mitral valve;

[0020] Figure 3B shows a top view of an embodiment of the present embodiment having a plurality of attachment devices disposed thereon;

[0021] Figure 3C shows a cross sectional view of the present embodiment having a plurality of attachment devices disposed thereon;

[0022] Figure 3D shows a perspective view of the present embodiment having a plurality of attachment devices disposed thereon;

[0023] Figure 4A shows a top view of the present embodiment of the present invention in a contracted state having a plurality of size support members positioned thereon;

[0024] Figure 4B shows a top view of the present embodiment of the present invention in a stretched state having a plurality of size support members positioned thereon; and

[0025] Figure 4C shows a cross sectional view of the present embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION [0026] The following detailed description and the accompanying drawings are intended to describe and show certain presently preferred embodiments of the present invention, and are not intended to limit the scope of the present invention in any way.

[0027] The self-molding annuloplasty ring of the present invention is generally used in surgical procedures to repair an incompetent tissue annulus. More specifically, the present invention is used to render an otherwise incompetent heart valve competent by decreasing the diameter of the opening at the valvular junction. As those skilled in the art will appreciate, the present invention may be manufactured with varying degrees of pre-tension and contractive force, thereby permitting variation of the contraction of the anterior or posterior annuli. In addition, the present invention simplifies the implantation procedure by pre- stretching the annulus ring to the diameter of the dilated annulus, and thereafter reducing the annulus with the contractive force exerted by the self-molding annulus ring.

[0028] Figure 1 shows a cross sectional view of the heart 10 having a bicuspid or mitral valve 12 positioned near the mitral valve annulus 14, and a tricuspid valve 16 positioned near the tricuspid valve annulus 18.

[0029] Various views of the present invention are illustrated in Figures 2A-2E. As shown in Figure 2A, the self-molding annulus ring 20 comprises a first planar surface 22 and an opposing second planar surface 24. Figure 2B shows the annulus ring 20 having a rectilinear segment 26 and an arcuate segment 28 connected by two curved ends 30 and 32, respectively. As illustrated, the annuloplasty ring 20 is generally "D" shaped to conform to the shape of a typical mitral valve annulus. Alternatively, the ring 20 may be manufactured in any shape suitable for implantation about an annulus. For example, the present invention may be manufactured in a generally round or oval shape thereby permitting use of the present invention to remodel an otherwise incompetent tricuspid valve. Figure 2C shows a cross-section view of the annuloplasty ring 20 having an elastic sizing member 36 positioned within an attachment sheath 38. The elastic sizing member 36 may comprise a plurality of biologically-compatible materials including, without limitation, elastomer, silicon, or any other material having sufficient resiliency to permit pre-stretching of the annuloplasty ring 20 prior to and during implantation, while having sufficient contractive force to decrease the size of the valve annulus to a desired diameter. The attachment sheath 38 provides a suitable material for suturing or otherwise attaching the annulus ring 20 to the tissue forming the valve annulus and promoting tissue growth therein. The attachment sheath 38 may comprise a plurality of biologically-compatible materials having comparable resiliency, including, for example, dacron, polyester knit, PTFE knit, and ePTFE knit. In an alternate embodiment, the attachment sheath may further comprise material treated with a biologically- compatible tissue growth factor or other medicament to aid in treating the attachment area. Those skilled in the art will appreciate the present invention reduces or eliminates the occurrence of systolic anterior motion (SAM), wherein the anterior leaflet of the mitral valve bulges into the left ventricular outflow track (LVOT) thereby obstructing blood flow into the aorta. An alternate embodiment of the present invention is shown in Figure 2D having the support member 40 positioned between the sizing member 36 and the attachment sheath 36. The support member 40 may be fabricated from a plurality of biologically-compatible materials having a comparable modulus of resiliency, including, for example, elastomer, rubber, silicon, or other material having sufficient resiliency to permit pre-stretching prior to implantation while providing support to the valve annulus. The support member 40 provides additional support of the valve and valve annulus Figure 2E shows a perspective view of the annuloplasty ring of the present invention.

[0030] The annulus ring may be attached to the annulus or surrounding tissue using a plurality of devices. Referring to Figures 3A, the annulus ring 20 may be attached to the valve annulus, either 14 or 18, with sutures 42. Figure 3B shows an alternate embodiment of the present invention utilizing attachment devices positioned on the annuloplasty ring. Like the previous embodiments, the present embodiment of the ring 44 comprises a rectilinear segment 46 attached to an arcuate portion 48 with two curved ends 50 and 52 positioned therebetween. A number of attachment devices 54 are positioned around the ring 44 to facilitate attachment of the ring 44 to the annulus tissue. Figure 3C shows the internal materials of the present invention having a sizing member 56 and an tissue-engaging sheath 58 disposed thereon. Like the previous embodiments, the sizing member 56 may be manufactured from a plurality of materials, including, for example, elastomer, silicon, or any other material having sufficient resiliency to permit pre-stretching of the annuloplasty ring 44 prior to and during implantation, while having sufficient contractive force to decreasing the size of the valve annulus to a desired diameter. Similarly, the tissue- engaging sheath 58 may be manufactured from a plurality of biologically- compatible materials having comparable resiliency, including, for example, dacron, polyester knit, PTFE knit, and ePTFE knit, or may incorporate tissue growth-enhancing materials. The attachment device 54 may comprise various tissue-engaging devices, including, for example, needles, barbs, or hooks. Those skilled in the art will appreciate the attachment devices 54 may be manufactured from a plurality of materials, including, without limitation, stainless steel, titanium, Nickel-Titanium alloy (Nitinol), or other biologically-compatible material. Figure 3D shows a perspective view of the annuloplasty ring of the present embodiment having a plurality of attachment devices 54 position about the device body 44.

[0031] Figures 4A-4C show an alternative embodiment of the present invention which includes size retaining members. Figure 4A shows the annuloplasty ring 60 of the present embodiment in a contracted state, wherein the ring 60 comprises a rectilinear segment 62, an arcuate segment 64, and two curved ends 66 and 68 positioned therebetween. As illustrated, the resilient ring 60 is comprised of a series of size supports 70 positioned about the exterior of the device. Figure 4B shows the resilient ring 60 stretched prior to implantation, having a resilient sizing member 72 positioned within the sizing supports 70. As shown in Figure 4C, the sizing support 70 has a receiving lumen 74 formed therein which is capable of receiving the sizing member 72. The attachment sheath 76 may be positioned on the exterior of the sizing support 70. Prior to implantation the resilient ring 60 is pre- stretched to a diameter roughly equivalent to the diameter of the dilated valve annulus and attached to the tissue use, for example, sutures, staples, or barbs. Once the resilient ring 60 is suitably positioned with the valve annulus and attached thereto, the insertion device (not shown) is removed and the ring 60 contracts causing each size support 70 to engage the proximate size supports 70, thereby limiting the amount of contraction the resilient ring 60 may achieve. The size supports 70 may be manufactured from a plurality of biologically-compatible materials, including, without limitation, stainless steel, titanium, or plastic. Like the previous embodiment, the sizing member 72 may be manufactured from a plurality of biologically compatible materials, including, for example, elastomer, silicon, or any other material having sufficient resiliency to permit pre-stretching of the annuloplasty ring 44 prior to and during implantation, while having sufficient contractive force to decrease the size of the valve annulus to a desired diameter. Similarly, the attachment sheath 58 may be manufactured from a plurality of resilient biologically-compatible materials, including, for example, dacron, polyester knit, PTFE knit, and ePTFE knit, or may incorporate tissue growth-enhancing materials.

[0032] The present invention further discloses a method of repairing a dilated or otherwise incompetent annulus. An exemplary open-chest surgical repair of a mitral valve will be disclosed herein. It should be understood the method disclosed herein is not intended to limit the scope of the present invention in any way.

[0033] The mitral valve partially forms the atrio-ventricular junction between the left atrium and left ventricle of the heart and is most easily reached through the wall of the left atrium. Those skilled in the art will appreciate the wall of the left atrium is may be accessed through a medial sternotomy procedure. To gain access to the mitral valve during the sternotomy, the surgeon rotates the heart to an anterior position, thereby providing access to the left atrium. An incision is made in the left atrium, thereby providing access to the mitral valve and the valve annulus.

[0034] To insert the annuloplasty ring of the present invention, the ring 20 is stretched for positioning on an insertion device. Those skilled in art will appreciate the present invention may be inserted on a plurality of insertion devices know in the art. Additionally, the annuloplasty ring may be positioned on the insertion device at the time of manufacture or immediately prior to implantation. Ideally, the annuloplasty ring should be stretched to a size commensurate with the diameter of the dilated valve annulus. The ring, positioned on the insertion device, is proximate to the valve annulus and attached to surrounding tissue in a plurality of manners, including, suturing, stapling, or any other biologically- compatible attachment technique. With the ring sufficiently attached, the insertion device may be removed, resulting in the annuloplasty ring contracting to its pre-stretched diameter, thereby rendering the valve competent. Those skilled in the art will appreciate the contractive force of the annuloplasty ring will determine the amount of post-implantation valvular dilation, thereby permitting the surgeon to accurately predict the post-implantation valve diameter.

[0035] In closing it is understood that the embodiments of the invention disclosed herein are illustrative of the principles of the invention. Other modifications may be employed which are within the scope of the invention; thus, by way of example but not of limitation, alternative insertion devices, and alternative attachment devices may be used. Accordingly, the present invention is not limited to that precisely as shown and described in the present invention.

Claims (18)

[0100] What is claimed is:

1. A self-molding annuloplasty ring for implantation in a heart annulus, comprising:

a resilient inner sizing member positioned within a resilient outer attachment sheath, said resilient inner sizing member and said resilient outer attachment sheath having a first diameter when contracted and a second diameter when stretched, wherein said first diameter is smaller than said second diameter.

2. The device of claim 1 wherein said resilient inner sizing member comprises a biologically compatible elastomer.

3. The device of claim 1 wherein said resilient outer attachment sheath comprises a biologically compatible fabric mesh.

4. The device of claim 1 wherein said resilient outer attachment sheath comprises Dacron.

5. The device of claim 1 wherein said resilient outer attachment sheath comprises a polyester knit.

6. The device of claim 1 wherein said resilient outer attachment sheath comprises PTFE knit.

7. The device of claim 1 wherein said resilient outer attachment sheath comprises ePTFE knit.

8. The device of claim 1 wherein said resilient outer attachment sheath comprises a medicament to induce tissue growth.

9. The device of claim 1 wherein said annuloplasty ring further comprises a plurality of attachment devices positioned thereon.

10. The device of claim 9 wherein said attachment devices comprise needles.

11. The device of claim 9 wherein said attachment devices comprise barbs.

12. The device of claim 9 wherein said attachment devices comprise hooks.

13. The device of claim 9 wherein said attachment devices are manufactured from stainless steel.

14. The device of claim 9 wherein said attachment devices are manufactured from a Nickel-Titanium alloy.

15. A sizable self-molding annuloplasty ring for implantation in a heart annulus, comprising:

a resilient inner sizing member;

a resilient outer attachment sheath enclosing said sizing member, said resilient outer sheath and said inner sizing member having a first diameter when contracted and a second diameter when stretched; and

a plurality of support members positioned on said resilient inner sizing member; said support member capable of cooperatively forming a sized ring having a third diameter.

16. The device of claim 15 wherein said third diameter is larger than said first diameter and smaller than said second diameter.

17. The device of claim 15 wherein said support members comprise a body member having a lumen formed therein, said lumen capable of receiving said sizing member therein.

18. The device of claim 16 wherein said attachment sheath is positioned on the exterior of said support members.