Abstract:
A prosthetic heart valve is disclosed which has a rigid shoulder with staple receiving means. Using the staple receiving means of the shoulder, the heart valve may be secured within the heart by stapling the shoulder of the prosthesis to the patient&#39;s tissue. Such a prosthesis is advantageous in that it may be secured in a much shorter time period than conventional valves thereby reducing the risks and complications of surgery.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to mechanical prosthetic heart valves, and, more particularly, to a mechanical prosthetic heart valve which may be surgically implanted in the heart of the patient in an expedient manner. 
     DESCRIPTION OF THE RELATED ART 
     Mechanical heart valves are conventionally constructed with a rigid annular body supporting one, two, or more leaflets. The action of these leaflets in opening and closing controls the flow of blood through the valve. The annular body of the heart valve is usually secured to what is referred to as a suture ring. The suture ring is generally comprised of a knit fabric tube made from DACRONJ, or some other biocompatible material, which permits a surgeon to sew the heart valve to the patient&#39;s heart tissue. Illustrative examples of such suture rings are disclosed in, for example, U.S. Pat. Nos. 5,397,348 and 5,397,346. 
     It is often necessary to completely remove defective heart valves and replace them with a prosthetic mechanical valve. Installing a mechanical heart valve is a major open heart surgical procedure. The procedure requires general anesthesia and a full cardiopulmonary bypass with complete cessation of cardiopulmonary activity. The invasiveness of the open chest procedure often produces a high degree of trauma and a significant risk of complications that increase the longer that cardiopulmonary activities are stopped. Unfortunately, hand sewing of the replacement heart valve into position using traditional suture rings, such as the suture ring described in U.S. Pat. No. 5,397,348, takes a significant amount of time and skill by the heart surgeon. 
     For the above reasons, it would be desirable to develop a heart valve and method of insertion therefor which significantly reduces the amount of time for the surgical procedure. It would further be desirable if such a surgical procedure did not require the precision of suturing. The present invention is directed to solving or reducing some of the above-described problems. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improved mechanical heart valve. The heart valve is comprised of a valve body and a stiffening ring coupled to the valve body. The stiffening ring is comprised of a body and a shoulder. At least one recess is formed in the shoulder, the recess being adapted for engaging at least one staple. The staples are used to secure the stiffening ring to the patient&#39;s heart tissue. In another embodiment of the present invention, a plurality of openings are formed in the shoulder, the openings being adapted for receiving a plurality of fasteners in the form of pins that are used to secure the stiffening ring to the patient&#39;s heart. 
    
    
     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 cross-sectional view of a human heart showing the placement of a mitral prosthetic heart valve and an aortic prosthetic heart valve; 
     FIG. 2 is a perspective view of an illustrative prosthetic heart valve of the present invention; 
     FIG. 3 is an exploded, perspective view of the prosthetic heart valve of FIG. 2; and 
     FIG. 4 is a cross-sectional view of an illustrative fabric-covered stiffening ring of the present invention. 
     FIG. 5 is a plan view of the shoulder area of a prosthetic heart valve employing one embodiment of the present invention; 
     FIG. 6 is a plan view of the shoulder area of yet another prosthetic heart valve employing one embodiment of the present invention; 
     FIG. 7 is a cross-sectional view of the shoulder area of yet another illustrative embodiment of the present invention; 
     FIG. 8 is an elevation view of an illustrative attachment device that may be used with the present invention; 
     FIG. 9 is another elevation view of the device shown in FIG. 8; 
     FIG. 10 is an elevation view of another illustrative attachment device that may be used with the present invention; and 
     FIG. 11 is another elevation view of the device shown in FIG.  10 . 
    
    
     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=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. 
     FIG. 1 is a cross-sectional view of a human heart  70  showing the placement of two prosthetic heart valves. A mitral valve  72  is shown positioned between the left atrium  71  and the left ventricle  73  of the heart. An aortic valve  74  is shown positioned between the left ventricle  73  and the ascending aorta  75 . Blood flows from the left atrium  71  through the mitral valve  72  into the left ventricle  73 . The left ventricle  73  pumps blood through the aortic valve  74  and the ascending aorta  75  to the body. 
     FIG. 2 is a perspective view of an illustrative example of a prosthetic heart valve, generally designated  10 , in accordance with our present invention. The heart valve  10  comprises an annular valve body  14  with pivoting leaflets  16 ,  18  and a stiffening ring  29 . In the embodiment shown, a bileaflet mechanical heart valve is illustrated. Single leaflet and multiple leaflet valves could also be used with our invention. The leaflets generally have a recess and a pivot tab to engage the recess and allow the leaflets  16 ,  18  to pivot between open and closed positions. A detailed explanation of how such leaflets may be used in the present invention is disclosed in U.S. Pat. No. 5,397,348, which is hereby incorporated by reference in its entirety. 
     As shown in FIG. 3, the annular valve body  14  has an exterior annular groove  22  on the outer surface  24  of the valve body  14 . The groove  22  is adapted to receive a lock wire  26 . The illustrative lock wire  26  depicted in FIG. 3 is used to attach the stiffening ring  29  to the annular valve body  14 . The illustrative embodiment of the stiffening ring  29  shown in FIG. 3 is comprised of a body  28 , a shoulder  57 , an opening  31  and a groove  30  formed on the inner surface  15  of the stiffening ring  29 . When installed, the illustrative lock wire  26  is inserted through the opening  31  and engages the groove  22  on the valve body  14  and the groove  30  on the body  28  of the stiffening ring  29 . Alternative types of devices and techniques for securing the stiffening ring  29  to the valve body  14  are described in U.S. Pat. No. 5,397,346, which is hereby incorporated by reference in its entirety. 
     As shown in FIG. 4, the angle at which the shoulder  57  extends away from the body  28  of the stiffening ring  29  may be varied as a matter of design choice. For example, the shoulder  57  may be positioned at an angle ranging from approximately 45E to 135E relative to the body  28  of the stiffening ring  29 . In one illustrative embodiment, the shoulder  57  extends approximately 90E in a radial direction from the cylindrical body  28  of the stiffening ring  29 . The shoulder  57  may be integrally formed with the body  28  of the stiffening ring  29 . However, those skilled in the art will appreciate that the shoulder  57  may also be a physically separate component that could be attached to the body  28  of the stiffening ring  29  by any suitable means, including welding, screwed threads, press fitting or any other suitable means. Of course, the shoulder  57  and the body  28  of the stiffening ring  29  may be of different materials of construction depending upon the particular surgical application at issue. 
     The stiffening ring  29  may be covered with a biocompatible fabric  80  which is usually in the form of a tube  75 . The tube  75  may be positioned so as to encompass the stiffening ring  29 , and may be attached to the stiffening ring  29  by weaving the fabric around the stiffening ring  29  and between a lower capture ring  34  and an upper capture ring  44 . The stiffening ring  29  has an upper recess  58  adapted for receiving an upper capture ring  44  and a lower recess  56  adapted for receiving a lower capture ring  34 . In one embodiment, the annular valve body  14  consists of pyrolitic carbon. It is a hard, wear-resistant, biocompatible carbon, well suited for the construction of artificial heart valves. The stiffening ring  29 , lock wire  26 , and the upper and lower capture rings  44 ,  34  may be made from a variety of biocompatible materials, such as titanium, cobalt-chromium or the like. 
     One illustrative technique for wrapping the stiffening ring  29  with a tube  75  comprised of a biocompatible fabric  80  will now be described. The stiffening ring  29  is placed within the tube  75 . Although not required, a suture  76  may then be positioned around the exterior surface  77  of the body  28  of the stiffening ring  29  approximately at the location where the shoulder  57  intersects the body  28  as shown in FIG.  4 . The suture  76  assists in securing the tube  75  to the stiffening ring  29 . Of course, other techniques could be used to accomplish these same results. For example, a ring (not shown) adapted to trap the tube  75  between the ring and the exterior surface  77  of the body  28  could be positioned at the intersection of the body  28  and shoulder  57  to secure the tube  75  to the body  28 . Additionally, a groove (not shown) could be formed on the outer surface  77  of the body  28  to retain the ring and/or the suture  76 . Any device or method that will assist in securing the fabric tube  75  to the surface  78  of the shoulder  57  and to the outer surface  77  of the body  28  will suffice. 
     Thereafter, a first end  32  of the tube  75  is wrapped outwardly around the lower edge  36  of the stiffening ring  29 , around the lower capture ring  34 , and then again around the lower edge  36  of the stiffening ring  29 . The wrapped lower capture ring  34  is then placed within the lower recess  56  of the stiffening ring  29 . When the first end  32  of the tube  75  is pulled taut, the lower capture ring  34  is secured in the recess  56  of the stiffening ring  29 . This crimps the tube  75  between the stiffening ring  29  and the lower ring  34  at a bend  38  of the tube  75  as shown in FIG.  4 . The first end  32  of the tube  75  is then secured to the tube  75  by stitches  90 , as shown in FIG.  4 . 
     A second end  91  of the tube  75  is then wrapped across the surface  82  of the shoulder  57 , around an upper edge  46  of the stiffening ring  29 , around the upper capture ring  44 , back around the upper edge  46 , across the surfaces  82  and  78  of the shoulder  57 . The wrapped upper capture ring  44  is then positioned in the upper recess  58 . When the second end  91  of the tube  75  is pulled taut, the upper capture ring  44  is pressed up against an upper edge  46  of the stiffening ring  29 . This crimps the tube  75  between the stiffening ring  29  and the upper ring  44  at a bend  48  of the tube  75 , as shown in FIG.  4 . The second end  91  of the tube  75  is then secured to the tube  75  by stitches  92 , as shown in FIG.  4 . 
     As shown in FIG. 4, the shoulder  57  has an illustrative recess  81  formed in the surfaces  78 ,  82 . The recess  81  is adapted to engage a device used to secure the stiffening ring  29  within the patient&#39;s heart. Although depicted in FIG. 4, it is not necessary to have recesses  81  formed in both the surfaces  78 ,  82  of the shoulder  57 . The number, size, position, and configuration of the recesses  81  may vary depending upon the type of attachment device employed to secure the stiffening ring  29  to the patient&#39;s heart. Likewise, the attachment device may vary depending upon the particular patient, heart valve and/or surgeon, etc. Generally, the attachment device will be such that, when installation of the stiffening ring  29  is complete, portions of the tube  75  covering the stiffening ring  29  and the patient&#39;s heart tissue remain in sufficient intimate contact such that the patient&#39;s heart tissue may grow and intermingle with the fabric  80  positioned around the stiffening ring  29 . 
     In one illustrative embodiment of the present invention, the stiffening ring  29  is secured to the patient&#39;s heart tissue by a plurality of fasteners  90  in the form of staples  79 . In this embodiment, the recesses  81  formed in the surface  82  and/or the surface  78  of the shoulder  57  are adapted to engage and crimp the staples  79  during the installation procedure. Whether the recesses  81  on the surface  82  or the recesses  81  on the surface  78  of the shoulder  57  are used may depend upon the particular procedure involved, as well as the surgeon=s desired surgical techniques. 
     The configuration and structure of the recesses  81  may be varied and may be governed by the type of fastener  90  employed. For instance, as shown in FIG. 5, the recesses  81  may be a continuous channel  85  formed in the surface  82  and/or the surface  78  of the shoulder  57 . In the illustrative embodiment depicted in FIG. 5, the channel  85  is formed in the surface  82  of the shoulder  57  and extends around the circumference of the shoulder  57  of the stiffening ring  29 . Of course, if desired, such a continuous channel  85  could also be formed in the surface  78  of the shoulder  57 . In this manner, when a circular stapler is employed, such as that of U.S. Pat. No. 5,533,661, which is hereby incorporated by reference in its entirety, the channel  85  receives the staples  79  and provides a rigid surface to form the staple, i.e., the channel  85  acts to alter the prongs  86  of the staple  79  from their approximately right angle beginning position to their crimped attaching position. Of course, the channel  85  may need not be continuous, it may only extend around a portion of the circumference of the shoulder  57 . 
     In another illustrative embodiment of the present invention, as shown in FIG. 6, a plurality of individual recesses  87  may be arranged adjacent to each other around the circumferences of the shoulder  57 . As described above, the recesses  87  may be formed on the surface  82 , the surface  78  of the shoulder  57 , or both, depending on the particular application. Typically, each recess  87  is in positional agreement with the prongs  86  of a staple  79  to be driven through the tube  75  and the tissue of the heart. Each recess  87  preferably has a semicircular indentation in order to assist in forming the staples  79 . 
     Another alternative technique for attaching the stiffening ring  29  to the patient&#39;s heart tissue  95  is shown in FIG.  7 . As shown therein, a plurality of openings  96  are formed in the shoulder  57 . The openings  96  are adapted to receive a fastener  90  in the form of a pin  91 . In one embodiment, the pin  91  is comprised of a flexible barb  94 , a shaft  98 , and a head  92 . In operation, the pin  91  is inserted through the patient&#39;s heart tissue  95  and into the opening  96  until the barbs  94  extend through the opening  96  and engage the surface  82  of the shoulder  57 . Of course, the openings  96  need not extend completely through the thickness of the shoulder  57 . 
     The size, shape and number of pins  91  used may be varied as a matter of design choice. Additionally, the pins  91  may be made from a variety of materials, such as, for example, stainless steel. As will be recognized by one skilled in the art upon a complete reading of the present application, the fastener  90  may take on a variety of different physical shapes other than the staples  79  and pins  91  specifically disclosed herein. For example, a collection of pins  91  may be configured as a single ring and inserted as a unit into a plurality of openings  96  formed in the shoulder  57 . In one illustrative embodiment of the present invention, the stapling of the heart valve into place involves employing a securing device (not shown) which is capable of inserting one or more fasteners  90  through the fabric covering  80  around the stiffening ring  29  and through the tissue of the heart such that the fasteners  90  hold the valve  10  in its proper location. While many devices may be appropriate, a suitable securing device and method of attaching fasteners  90  in the form of stapes  79  is taught in U.S. Pat. No. 5,533,661, where is hereby incorporated by reference in its entirety. 
     The stiffening ring  29  may be releasably attached to the securing device by a variety of techniques. Whatever means is selected, it should allow for quick and efficient attachment and release of the stiffening ring  29  to the securing device. One illustrative attachment device  100  for releasably securing the stiffening ring  29  to the securing device is shown in FIGS. 8 and 9. Another illustrative attachment device  200  is depicted in FIGS. 10 and 11. 
     The attachment device  100  may be attached to the securing device (not shown) by a variety of techniques, e.g., screwed threads, welding, snap-on, etc. As shown in FIGS. 8 and 9, the illustrative attachment device  100  is comprised of a first half  110  and a second half  112  that are rotatably coupled together at pin  114 . The attachment device  100  is further comprised of lugs  116 ,  118  that are adapted to engage the surface  82  of the shoulder  57  of the stiffening ring  29 . As shown in FIG. 8, the attachment device is further comprised of a locking sleeve  102  that is used to move the attachment device  100  from its engaged position, as shown in FIG. 8, to its disengaged positioned, as shown in FIG.  9 . 
     The locking sleeve  102  is moved in the direction indicated by arrow  122  to engage the attachment device  100  with the stiffening ring  29 . This situation is depicted in FIG.  8 . The locking sleeve  102  is moved in the direction indicated by arrow  120  to disengage the attachment device  100  from the stiffening ring  29 . This situation is depicted in FIG.  9 . Note that, due to retraction of the locking sleeve  102  in the direction  120 , the attachment device  100  is effectively collapsed thereby allowing the halves  110 ,  112  to rotate relative to one another to a point such that the lugs  116  and  118  will pass through the stiffening ring  29 . The movement of the locking sleeve  102  may be accomplished by withdrawing the sleeve  102  through the securing device (not shown) such that it may be manually actuated by a surgeon during use. 
     An alternative attachment device  200  may be attached to the securing device (not shown) by a variety of techniques, e.g., screwed threads, welding, snap-on, etc. As shown in FIGS. 10 and 11, the illustrative attachment device  200  is comprised of a first half  210  and a second half  212  that are rotatably coupled together at pin  214 . The attachment device  200  is further comprised of lugs  216 ,  218  that are adapted to engage the surface  82  of the shoulder  57  of the stiffening ring  29 . As shown in FIG. 10, the attachment device is further comprised of a mechanical linkage system  202  that is used to move the attachment device  200  from its engaged position, as shown in FIG. 10, to its disengaged positioned, as shown in FIG.  11 . The illustrative mechanical linkage system  202  depicted in the drawings is comprised of bars  206  and  204 , and actuating rod  208 . The bar  206  is pinned to the half  212  at pin  207 . The bar  204  is pinned to the half  210  at pin  205 . The bars  206 ,  204  and actuating bar  208  are all pinned together at pin  209 . 
     The actuating bar  208  is moved in the direction indicated by arrow  222  to engage the attachment device  200  with the stiffening ring  29 . This situation is depicted in FIG.  10 . The actuating bar  208  is moved in the direction indicated by arrow  220  to disengage the attachment device  200  from the stiffening ring  29 . This situation is depicted in FIG.  11 . Note that, due to retraction of the actuating bar  208  in the direction  220 , the mechanical linkage system  202  is effectively collapsed thereby allowing the halves  210 ,  212  to rotate relative to one another to a point such that the lugs  216  and  218  will pass through the stiffening ring  29 . The movement of the actuating bar  208  may be accomplished by extending the bar  208  through the securing device (not shown) such that it may be manually actuated by a surgeon during use. 
     In operation, after the stiffening ring  29  has been wrapped with the appropriate biocompatible material  80 , the stiffening ring  29  is releasably attached to the securing device (not shown) through use of the attachment device  100  described above. Thereafter, the stiffening ring  29  is then positioned within the patient&#39;s heart, and the securing device is actuated one or more times to secure the stiffening ring  29  to the patient&#39;s heart tissue using a plurality of fasteners  90 , such as staples  79  or pins  91 . Next, the surgeon disengages the attachment device  100  from the stiffening ring  29  by retraction of the actuating bar  108  in the direction indicated by arrow  120 , as shown in FIG.  9 . Once released, the securing device and attachment device may be removed from the patient&#39;s body. A valve body  14  comprising leaflets  16  and  18  may then be attached to the stiffening ring  29  by insertion of lock wire  26  through the opening  31  in the stiffening ring  29 . 
     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.