Abstract:
An improved mechanical heart valve that reduces the time required to perform heart valve replacement surgery is provided. The mechanical heart valve is comprised of a valve body and a plurality of staples extending around the valve body that are coupled to the valve body through at least one intermediate member.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to prosthetic heart valves, and, more particularly, to a sutureless cuff for securing a prosthetic heart valve within a patient&#39;s heart. 
     2. Description of the Related Art 
     It is well known that several heart diseases may result in a variety of disorders of the cardiac valves. For example, rheumatic fever may cause the shrinking of valve orifices. The resulting defects in heart valves hinder the normal operation of the heart. For example, defective closing of one of the valves, referred to as valvular insufficiency, may result in the accumulation of blood in the heart or regurgitation of blood past the defective valve. 
     To overcome these and other types of problems associated with defective heart valves, it is often necessary to completely replace the defective heart valve with a mechanical heart valve. Mechanical heart valves may come in a variety of styles and configurations. For example, a heart valve may include an annular valve body and a knit fabric sewing or suture cuff coupled to the valve body. Illustrative valves of this type are described in U.S. Pat. No. 5,397,346 entitled “Prosthetic Heart Valve With Sewing Ring” and U.S. Pat. No. 5,397,348 entitled “Mechanical Heart Valve With Compressible Stiffening Ring,” both of which are hereby incorporated by reference in their entirety. In these type of mechanical heart valves, the suture cuff is sewn in place on the patient&#39;s heart tissue. Over time, the patient&#39;s heart tissue grows into the fabric to permanently seal the mechanical heart valve against leakage. 
     In general, heart valve replacement surgery is expensive and requires a highly-skilled team of doctors and support staff. During heart valve replacement surgery, the patient is maintained on a heart/lung bypass machine. While this procedure has worked very well, the longer the patient is on the heart/lung bypass machine, the greater the risk to the patient. It is desirable that the heart valve replacement be accomplished as quickly as possible. However, with the above-described heart valves, sewing the suture cuff to the patient&#39;s heart is time-consuming and tedious, further increasing the time that the patient is on the heart/lung bypass machine. 
     The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a mechanical heart valve. The mechanical heart valve is comprised of a valve body and a plurality of staples extending around and fixedly attached to a first member, the first member being coupled to the valve body. 
     In another illustrative embodiment of the present invention, a mechanical heart valve is comprised of a valve body and a stiffening ring adapted for coupling to the valve body. The invention further comprises a backing plate that is adapted for coupling to the stiffening ring, and a plurality of staples that can be positioned on the backing plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which: 
     FIG. 1 is a perspective view of one embodiment of the present invention; 
     FIG. 2 is an exploded view of the device shown in FIG. 1; 
     FIG. 3 is a cross-sectional view of one illustrative embodiment of the sutureless cuff of the present invention; 
     FIG. 4 is an illustrative alternative embodiment of the present invention; 
     FIG. 5 is another illustrative alternative embodiment of the present invention; 
     FIG. 6 is a plan view depicting one illustrative spacing arrangement of the staples that may be used with the present invention; and 
     FIG. 7 is another plan view depicting one illustrative spacing arrangement of the staples that may be used with the present invention. 
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     As shown in FIGS. 1 and 2, a prosthetic heart valve  10  may be comprised of an annular valve body  14 , a lock wire  26 , a stiffening ring  28  and a sutureless cuff  12 . The valve body  14  is comprised of an outer surface  24  having an exterior groove  22  formed therein. In the illustrative embodiment disclosed herein, the heart valve  10  is comprised of two pivoting leaflets  16 ,  18 . Of course, those skilled in the art will recognize that the heart valve  10  could be comprised of single or multiple leaflets and could even be a different type of valve, e.g., a ball valve. 
     The stiffening ring  28  has a like circumferential groove  30  formed in its inner surface  33  and a hole  31  that extends through the stiffening ring  28 , intersecting with the groove  30 . The lock wire  26  is used to couple the stiffening ring  28  to the valve body  14 . In particular, the lock wire  26  may be inserted through the hole  31  into the region defined by the circumferential groove  30  on the stiffening ring  28  and the exterior groove  22  on the valve body  14 . When thus inserted, the lock wire  26  prevents relative vertical movement between the stiffening ring  28  and the valve body  14 . 
     FIG. 3 is a cross-sectional view of one embodiment of the present invention. As shown therein, the sutureless cuff  12  may be comprised of a plurality of pre-formed staples  50 , a backing plate  52 , and a knit fabric tube  32 . The fabric tube  32  may be coupled to the stiffening ring  28 , through use of an upper capture ring  44  and a lower capture ring  34 . In the illustrative embodiment shown in FIG. 3, the fabric tube  32  acts to loosely couple the combination of the backing plate  52  and staples  50  to the stiffening ring  28  and, ultimately, to the valve body  14  by use of the lock wire  26 . A hole (not shown) is provided in the backing plate  52  to allow the lock wire  26  to be inserted through the hole  31  in the stiffening ring  28 . Of course, those skilled in the art will recognize that a variety of different mechanical arrangements may be made that will allow the staples  50  to be coupled to the valve body  14  indirectly through one or more intermediate member, such as the stiffening ring  28  and/or the backing plate  52 . For purposes of this invention, it is sufficient that the staples  50  be coupled to the valve body  14 , directly or indirectly, through the use of one or more parts, such that, when the staples  50  are set, they may be used to secure the valve body  14  in the proper position in the patient&#39;s heart. Of course, this coupling of the staples  50  to the valve body  14  need not be a rigid connection. 
     The staples  50  may be coupled to the backing plate  52  by a variety of techniques, e.g., welding or forming slots in the backing plate  52 . In one embodiment, the staples  50  may be attached to the backing plate  52  by, for example, welds  63 . Alternatively, as shown in FIG. 4, the staples  50  may be formed integrally with the backing plate  52  to form a single unit. In another embodiment, as shown in FIG. 5, the staples  50  may be attached to the stiffening ring  28  by, for example, welding. 
     As shown in FIG. 3, the ends  51  and  55  of the staples  50  define a generally triangular shaped opening  53  into which will be positioned the patient&#39;s heart material. Of course, the staples  50  may be modified so as to define openings between the ends  51 ,  55  of the staples  50  that are other than a generally triangular cross-section. For example, the staples  50  could be configured such that the opening between the ends  51 ,  55  of the staple  50  define a generally rectangular or semi-circular opening. In one embodiment, the distance between the ends  51 ,  55  of the staple  50  may vary from approximately 0.375″-0.5″. The ends  51 ,  55  of the staple  50  may extend radially outward from the backing plate  52  a distance that may vary in the range of approximately 0.3125″-0.375″. Additionally, as those skilled in the art will recognize, the staples  50  may have a variety of cross-sectional configurations, e.g., circular, rectangular, square, etc. In one illustrative embodiment, the staples  50  have a circular cross-section of approximately 0.060 inch in diameter. 
     The size, number and location of the staples  50  positioned around the stiffening ring  28  are matters of design choice. Generally, the larger the diameter of the heart valve  10 , the more staples  50  will be required. The number of staples  50  used, as well as the spacing between the staples  50 , are matters of design choice. For example, for a 33 mm diameter valve, twelve of the staples  50 , spaced approximately 30 degrees apart, may be positioned around the perimeter of the stiffening ring  28  as shown in FIG.  6 . For a 19 mm diameter valve, nine of the staples  50 , spaced at approximately 40 degrees, may be employed as shown in FIG.  7 . Of course, the number and spacing of the staples  50  may be modified if desired or warranted by the particular application. 
     As will be readily recognized by those skilled in the art, the valve body  14 , lock wire  26 , stiffening ring  28 , backing plate  52  and staples  50  may be manufactured from a variety of materials. In one illustrative embodiment, the valve body  14  may be made of pyrolytic carbon, a hard, wear-resistant, biocompatible material, and the lock wire  26 , stiffening ring  28  and the backing plate  52  may be comprised of a biocompatible material such as titanium, cobalt-chromium, or the like. The staples  50  may be made from a variety of materials, such as, plastic or metallic materials. In one embodiment, the staples  50  may be made of stainless steel. The fabric tube  32  may be made of a variety of materials readily known to those skilled in the art. For example, the fabric tube  32  may be made of a polyester or PTFE fabric or of DACRON™ material. 
     The manner in which the sutureless cuff  12  may be assembled is similar to the techniques described in U.S. Pat. Nos. 5,397,346 and 5,397,348 for the assembly of the suture ring disclosed therein. U.S. Pat. Nos. 5,397,346 and 5,397,348 are hereby incorporated by reference in their entirety. The construction of the sutureless cuff  12  can be understood by reference to FIGS. 1 and 3. Construction of the sutureless cuff  12  begins with a knit fabric tube  32 . The fabric tube  32  has an inner diameter that is approximately the same as the outer diameter of the stiffening ring  28 . The stiffening ring  28  is placed within the fabric tube  32 . The lower capture ring  34  is placed on the outside of the fabric tube  32  and pressed toward the upper edge  36  of the recess  37  formed in the stiffening ring  28 . This crimps the fabric tube  32  between the stiffening ring  28  and the lower capture ring  34  at a bend  38 , as seen in FIG. 3. A lower end  40  of the fabric tube  32  is wrapped downwardly around the lower capture ring  34 , and the lower capture ring  34  is then pressed into the recess  37  as shown in FIG.  3 . The lower end  40  of the fabric tube  32  will be attached to an upper end  59  of the fabric tube  32 , as described more fully below. 
     After the lower capture ring  34  is positioned in the recess  37 , an upper capture ring  44  is placed on the outside of the fabric tube  32  and pressed toward a lower end  46  of the recess  47  formed in the stiffening ring  28 . As with the lower capture ring  34 , this forms a bend  48  in the fabric tube  32  that is captured between the stiffening ring  28  and the upper capture ring  44 . To complete the attachment of the sutureless cuff  12  to the stiffening ring  28 , an upper end  59  of the fabric tube  32  is folded down over the staples  50  and, if used, the backing plate  52 , and the upper end  59  and the lower end  40  of the fabric tube  32  are stitched together around the perimeter of the stiffening ring  28 . If desired, a filler  56  such as texturized yarn, TEFLON™ felt, or molded silicon may be positioned within the fabric tube  32  adjacent the staples  50 . 
     As is readily apparent to those skilled in the art, the sutureless cuff  12  may be assembled and attached to the valve  14  outside of the patient&#39;s body. Once properly positioned in the patient&#39;s heart, a device (not shown) may be actuated to deform the staples  50  such that the ends  51 ,  52  penetrate the heart material and thereby secure the valve within the heart. Thereafter, over time, the patient&#39;s heart tissue grows into the fabric providing a secure seal for the heart valve. 
     The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.