Patent Publication Number: US-2004059412-A1

Title: Heart valve holder

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention relates generally to medical devices, and, more particularly, to a heart valve holder that may be used by a surgeon during the process of replacing damaged or diseased heart valves.  
       [0002] The human heart includes four valved chambers (left and right atria and ventricles) for pumping blood through the body. Each ventricle has two valves to control the inflow of blood from the atria and the outflow of blood to the lungs (right ventricle) or to the rest of the body (left ventricle). In the case of the right ventricle, the inlet and outlet valves are the tricuspid and pulmonary valves, and in the case of the left ventricle they are the mitral and aortic valves. During each cycle of the heart&#39;s operation, the mitral and tricuspid valves open simultaneously to allow blood to flow into the ventricles while the aortic and pulmonary (outlet) valves are closed. The ventricles then contract, and the resulting blood pressure therein closes the mitral and tricuspid (inlet) valves while opening and forcing blood outward through the aortic and pulmonary valves.  
       [0003] In some individuals one or more of the foregoing valves may not function properly, usually as a result of disease-induced valve damage, degeneration or a congenital defect. In the case of the aortic valve, in particular, dysfunction often results from a narrowing of the valve orifice (stenosis), or from valve regurgitation such that the valve does not fully open or close. Severe heart valve dysfunction is life threatening. For the past several years, severe valve dysfunction has been treated by replacing the incompetent valve with a mechanical prosthesis, or alternatively, with a bioprosthetic valve (i.e., a valve comprising human or animal tissue). The terms “bioprosthetic valve” and “tissue valve” as used herein are synonymous and are used interchangeably. Tissue valves have the advantage of a lower incidence of blood clotting (thrombosis). Hence, patients receiving such a tissue valve, unlike those receiving a mechanical valve, do not usually require prolonged anticoagulation therapy with its potential complications and patient inconvenience.  
       [0004] Surgically-implanted heart valve prostheses have extended the life expectancy of many patients with defective natural heart valves. By way of example, an aortic prosthetic valve is implanted in the patient during a surgical procedure in which a segment of the aorta near the natural valve is slit open so that the malfunctioning leaflets can be cut out and the prosthetic valve is sutured within an intact segment of the aorta adjacent to the heart. The surgical procedure is exacting because of the difficulty of accessibly exposing the aorta for the surgeon. Accordingly, the valve itself lies in a relatively cramped space. Because of the crowded surgical field, holding the prosthesis in place while the surgeon places the sutures to attach it to the interior of the patient&#39;s aorta presents an especially challenging problem.  
       [0005] In the case of human aortic valve replacement, a commonly used tissue valve can be categorized as an allograft (usually an aortic valve from a human cadaver, sometimes referred to as a homograft). In addition, some human aortic valves have been replaced with pulmonary autografts; that is, a pulmonary valve from the same patient which in turn is then replaced with an allograft valve or tissue valve constructed from nonvalvular tissue (e.g., pericardium).  
       [0006] Xenografts (heart valves comprising tissue from a non-human donor animal) are also commonly used for human valve replacement. In particular, the porcine aortic valve is often used since it is similar in anatomy to the human aortic valve (both being trileaflet) and is readily available in a variety of sizes. The porcine aortic xenograft has been used for human valve replacement, both stented, i.e., mounted in a frame, and unstented, i.e., without a frame.  
       [0007] Unstented bioprosthetic valves require a more exacting surgical procedure for insertion into a patient than do stented valves. Correct valve selection, orientation, and sizing are important to avoid valve distortion and subsequent malfunction. Moreover, stentless tissue valve implantation is made even more difficult due to the nature of the product itself. Stentless tissue valves are very flexible and lack any significant structural rigidity. The absence of a fixed structure within the valve that can retain the valve in a desired position for suture attachment is a persistent problem in stentless valve implantation. Even routine handling and positioning of the valves is very difficult during the surgical procedure.  
       [0008] The presently used technique of implanting an unstented xenograft or allograft tissue valve requires holding the flaccid valve between the fingers and estimating the appropriate suture placement relative to the diseased aortic root. Such a technique complicates the insertion procedure and frequently results in geometric mismatch of the replacement valve with the recipient&#39;s native aortic root. Due to the foregoing difficulties, many surgeons currently prefer to implant stented bioprosthetic valves even though unstented valves, both xenografts and allografts, minimize turbulence and should therefore reduce thrombosis and embolism in comparison to stented valves. Moreover, due to the cramped working area, protection of the valve leaflets during the surgical procedure is also important. That is, it is very desirable to reduce the risk of damaging the heart valve leaflets during surgery.  
       [0009] The present invention is directed to a method and system to solve, or at least reduce, some or all of the aforementioned problems.  
       SUMMARY OF THE INVENTION  
       [0010] The present application is directed to various embodiments of a bioprosthetic heart valve holder. In one illustrative embodiment, a heart valve holder in accordance with the present invention comprises a housing, a plurality of hollow members coupled to the housing, each of the plurality of hollow members having a plurality of openings formed therein, and an inlet port coupled to the housing, the inlet port coupled to a vacuum source whereby a vacuum pressure may be supplied via the inlet port to the openings in the hollow members. As used herein, the term and “vacuum pressure” refers to a pressure less than the ambient air pressure adjacent to a prosthetic heart valve. By engaging the openings in the hollow members directly to a portion of a bioprosthetic heart valve, particularly to a tissue component of such a valve, a suction force may be applied to retain the valve on the holder. Specifically, the hollow members are positioned adjacent to a heart valve, and the vacuum pressure creates a suction against the valve which is used to secure the valve to the heart valve holder. By employing a relatively low vacuum pressure, a relatively strong suction force may be developed because of the greater pressure differential between the vacuum pressure and the ambient pressure. Correspondingly, a relatively high vacuum pressure may be used to employ a relatively weaker suction force upon the valve.  
       [0011] In a particular illustrative embodiment, the plurality of openings in the hollow members are formed in an exterior surface of the hollow members, and the hollow members are adapted to engage, preferably by direct contact, an interior surface of a heart valve. In another embodiment, the plurality of openings on the hollow members are formed on an interior surface of the hollow members, and the hollow members are adapted to engage an external surface of a heart valve.  
       [0012] In other illustrative embodiments, the heart valve holder employs at least one balloon-type structure to assist in holding the heart valve during implantation. In one embodiment, the heart valve holder comprises a housing, at least one inlet port coupled to the housing, and at least one balloon member coupled to the housing and in fluid communication with the inlet port, the balloon member adapted to engage at least a portion of an interior surface of a heart valve when a fluid is supplied to the balloon member via the inlet port.  
       [0013] In a particular embodiment, the holder comprises a balloon member positioned around an exterior surface of the housing, sealingly coupled to the housing, and in fluid communication with the inlet port, whereby the balloon member is adapted to be inflated by introduction of a fluid through the inlet port and the openings. In yet another illustrative embodiment, the heart valve holder comprises a balloon member sealingly coupled to a bottom surface of the housing and in fluid communication with the inlet port, the balloon member having at least three portions, each of which are adapted to engage, when inflated, at least a portion of a sinus of Valsalva in a heart valve.  
       [0014] In a further embodiment, the heart valve holder comprises three balloon members, each of which are operatively coupled to and in fluid communication with at least one inlet port, each of the balloon members adapted to engage, when inflated, at least a portion of a sinus of Valsalva in a heart valve and one another. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0015] 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:  
     [0016] FIGS.  1 A- 1 C depict one illustrative embodiment of the present invention;  
     [0017] FIGS.  2 A- 2 D depict another illustrative embodiment of the present invention; and  
     [0018] FIGS.  3 A- 3 B depict yet another illustrative embodiment of the present invention. 
    
    
     [0019] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are provided in the drawings and described herein in detail. It should be understood, however, that the description 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  
     [0020] 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. 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 health-related (or human-related), system-related and business-related constraints, which will vary from one implementation to another. While such a development effort might be complex and time-consuming, it is nevertheless a routine undertaking for those of skill in the art having the benefit of the present disclosure.  
     [0021] Although the various regions and structures of the heart are depicted in the drawings as having very precise, sharp configurations and profiles, those skilled in the art recognize that, in reality, these regions and structures are not as precise as indicated in the drawings. Additionally, the relative sizes of the various features and structures depicted in the drawings may be exaggerated or reduced as compared to the size of those features or structures on real-world devices. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present invention.  
     [0022] In general, the present invention is directed to various embodiments of a heart valve holder. The valve holders described herein may be used to hold a variety of different heart valves, and they may be used in connection with a variety of different surgical procedures, e.g., full-root, root-inclusion, and complete and modified sub-coronary procedures, etc. Thus, neither the specific type of valve used nor the type of surgical procedure performed should be considered a limitation of the present invention unless such limitations are clearly set forth in the appended claims.  
     [0023] Further, as will be recognized by those skilled in the art after a complete reading of the present application, the devices disclosed herein may be employed by a variety of different materials and techniques. For example, at least a portion of the device may be supplied with the heart valve provided to a surgeon. Alternatively, in practice, the inventions disclosed herein may be essentially instruments that are used in the heart valve installation procedure.  
     [0024] In general, the present application is directed to a variety of heart valve holders. More generally, the embodiments depicted in FIGS.  1 A- 1 C are directed to a holder that involves the use of vacuum suction to couple the heart valve to the holder, while the embodiments depicted in FIGS.  2 A- 2 D and  3 A- 3 B involve the use of inflatable balloon-type structures to accomplish the same task. The details of each embodiment will be described further below.  
     [0025] FIGS.  1 A- 1 C depict a valve holder  100  adapted to hold a stentless valve  10  through use of vacuum pressure. In one embodiment (see FIGS.  1 A- 1 B), the valve holder  100  is adapted to be positioned on the inside of the stentless valve  10 , i.e., to engage an inner or blood contacting surface of the valve. In another embodiment (see FIG. 1C), holder  100  is adapted to be positioned on the outside of the stentless valve  10 . Alternative embodiments (not shown) using both inside and outside engagement members, are also contemplated.  
     [0026] As shown in FIGS.  1 A- 1 B, the valve holder  100  is comprised of a plurality of hollow members  102  that are coupled to a housing  104 . Each of the hollow members  102  has a plurality of openings  110  formed therein (only depicted on one hollow member  102  for purposes of clarity). The housing  104  has a structural member  106  that is adapted to be coupled to a handle (not shown) by a variety of known techniques. For example, the structural member  106  may have a threaded male connection that is adapted to engage a corresponding female threaded connection in the end of a handle. The housing  104  further comprises a vacuum port  108 . The housing  104  and hollow members  102  are arranged and configured such that the hollow members  102  are in fluid communication with the vacuum port  108 . Although not depicted in the drawings, a shut-off valve may also be positioned on the vacuum port  108 . The hollow members  102  and openings  110  may be considered to constitute a conduit means that allow a vacuum pressure to be applied to a heart valve to be implanted in a patient. Depending upon the physical configuration of the conduit means, the vacuum pressure may be applied to an interior or an exterior surface of a heart valve.  
     [0027] The valve holder  100  may be manufactured in a variety of configurations, and it may be made from a variety of materials. For example, the hollow members  102  may be made from a variety of materials, e.g., plastic, stainless steel, etc., and the number of hollow members  102  may vary. In the embodiment depicted in FIGS.  1 A- 1 B, the heart valve holder  100  is comprised of eight hollow members  102 , although more or fewer could be used. The hollow members  102  may be manufactured from structural members such as round tubing, square tubing, etc. Moreover, the axial length  109  of the heart valve holder  100  may also vary, e.g., the length  109  may range from approximately one (1) to three (3) inches.  
     [0028] The number, size and configuration of the openings  110  on the hollow members  102  may vary. For example, the openings  110  may have a circular, elliptical, or rectangular configuration. Moreover, the number and location of the openings  110  need not be uniform on each of the hollow members  102 . For example, the openings  110  may be spaced apart by a distance of approximately 0.1-0.125 inch. In one particularly illustrative embodiment, the hollow members  102  are comprised of hollow stainless steel tubes having an outer diameter of approximately 0.05″, and there are approximately 6-8 openings  110  spaced apart approximately 0.125″ on each of the hollow members  102 . In the embodiment depicted in FIGS.  1 A- 1 B, the openings  110  are positioned on an exterior surface  114 , i.e., an outwardly facing surface, of the hollow members  102  such that the openings  110  may engage an interior surface  12  of the stentless valve  10 .  
     [0029] In the embodiment depicted in FIG. 1C, the hollow members  102  are positioned so as to engage an exterior surface  14  of the stentless heart valve  10 . In the embodiment depicted in FIG. 1C, the openings  110  are positioned on an interior surface  116 , i.e., an inwardly facing surface, of the hollow member  102  such that they may engage an exterior surface  14  of the stentless heart valve  10 . For purposes of clarity, only three hollow members  102  of the valve holder  100  are depicted in FIG. 1C. Moreover, only four representative openings  110  (with use of hidden lines) formed in one of the hollow members  102  are depicted in FIG. 1C, although more or fewer openings can be used. The number of hollow members  102  used on the valve holder  100  may vary depending upon whether it is adapted to engage the interior surface  12  or exterior surface  14  of the heart valve  10 . For example, if the heart valve holder  100  is to be used to engage the exterior  14  of the heart valve  10 , fewer hollow members  102  may be used so as to avoid the external protrusions  16  associated with the sinuses of Valsalva in the heart valve  10 . For example, a heart valve holder  100  may be comprised of 3-6 such hollow members  102 . Additionally, the valve holder  100  may be sized for a unique size of heart valve  10 .  
     [0030] In operation, an access opening or slit may be cut in the aorta. Thereafter, the diseased or damaged heart valve (not shown) may be removed. After the surgeon has confirmed the appropriate size of the replacement stentless heart valve  10 , the heart valve  10  may be positioned around the valve holder  100 , depicted in FIGS.  1 A- 1 B, or it may be positioned within the interior region  120  defined by the hollow members  102  of the valve holder  100  depicted in FIG. 1C. Thereafter, vacuum pressure from a source within the operating room may be applied to the vacuum port  108  and to the openings  110 . The stentless heart valve  10  may then be moved or adjusted as desired by the surgeon. In some situations, the vacuum supply may be regulated such that a relatively weak vacuum pressure is employed when positioning the heart valve  10  on the heart valve holder  100 , and a relatively stronger vacuum pressure is supplied after the heart valve  10  is correctly positioned on the valve holder  100  by the surgeon.  
     [0031] Once the heart valve  10  is properly positioned on the heart valve holder  100 , a handle (not shown) may be secured to the structural member  106  of the housing  104 . The heart valve  10  may then be properly positioned in the heart, and the surgeon may use a plurality of stitches to secure the distal end  20  of the heart valve  10  in position within the heart. Thereafter, the vacuum pressure may be released, the valve holder  100  withdrawn, and the surgeon may complete the installation of the stentless heart valve  10 . Alternatively, the surgeon may also secure the proximal end of the valve before releasing the vacuum pressure and removing the valve.  
     [0032] In general, the valve holders depicted in FIGS.  2 A- 2 D involve the use of a balloon-type member to hold the stentless heart valve  10 . As shown in FIGS.  2 A- 2 B, one embodiment of the heart valve holder  200  is comprised of a cylindrical housing  202 , a structural member  204 , a balloon member  206  and a fluid inlet  208  having a valve  211  formed thereon. The housing  202  and balloon member  206  are configured such that the balloon member  206  is in fluid communication with the fluid inlet  208 . The balloon member  206  is positioned around an exterior surface  207  of the housing  202  and sealingly engaged or coupled to the housing  202 . Such a sealing engagement may be accomplished by use of an adhesive, or other known techniques. The balloon member  206  may be comprised of a variety of materials, such as a silicone rubber material. Also depicted in FIG. 2A is a syringe  210  that, in one embodiment, may be used to inject a fluid, such as air or saline into the housing  202  so as to inflate the balloon member  206 , as described more fully below.  
     [0033] The housing  202  has a plurality of openings  214  formed around the circumference of the housing  202 , as indicated in FIG. 2B. However, in some situations, only a single opening  214  may be formed in the housing  202 . As described more fully below, a fluid, such as saline or air, may be supplied via the fluid inlet  208  to the housing  202  and, thereafter, to the balloon member  206  via the openings  214  in the housing  202 . In this manner, the balloon may be inflated when desired.  
     [0034] The member  204  may be connected to a handle (not shown) after the heart valve  10  is positioned around the heart valve holder  200 . Alternatively, such a handle member may be directly coupled to the housing  202  by means of a threaded recess (not shown) formed in the housing  202 . The housing  202  may be manufactured from plastic, stainless steel or other like material. Moreover, the size, shape and configuration of the housing  202  may be varied as a matter of design choice. Typically, the housing  202  and balloon member  206  are sized such that, when the balloon member  206  is deflated, there will be approximately ⅛″ clearance between the interior surface  12  of the stentless heart valve  10  and the balloon member  206 . In practice, the valve holder  200  may be sized such that it is only useful for one particular size heart valve  10 . Moreover, the length  209  of the heart valve holder  200  may vary, e.g., from approximately 1-3 inches.  
     [0035] In the embodiment depicted in FIGS. 2C and 2D, a balloon member  230  is positioned around a bottom surface  222  of the housing  220  of the valve holder  240 . The balloon member  230  is sealingly engaged or coupled to the housing  220 . Similar to the previous embodiment, the housing  220  and the balloon member  230  are configured such that the balloon member is in fluid communication with the fluid inlet  208 . In this embodiment, the balloon member  230  has three portions  230 A (only two of which are shown) that are configured such that, when inflated, the balloon portions  230 A will substantially fill or nest within the sinuses of Valsalva in the heart valve  10 . Fluid, e.g., saline or air, introduced via the fluid inlet  208  is used to inflate the balloon member  230  via a plurality of openings  224  formed in a bottom surface  222  of the housing  220 . Alternatively, only a single opening  224  may be formed in the bottom surface  222  of the housing  220 . The balloon members may be comprised of a variety of materials, such as a thin elastomer or silicone. Moreover, the balloon members  206 ,  230  may be considered to constitute inflatable means that, when inflated, are adapted to engage at least a portion of an interior surface of a heart valve.  
     [0036] In operation, as with the previous embodiments, after the surgeon confirms the proper size of the heart valve  10  to be implanted, the heart valve  10  may be positioned around the heart valve holder  200 ,  240 , and fluid may be introduced into the housing  202 ,  220  through the fluid inlet  208 . In one embodiment, the syringe  210  may be used to introduce such fluid. In other embodiments, the fluid may be introduced from another source, such as an air supply source within a hospital operating suite. In a specific embodiment, the fluid inlet  208  is provided with the valve  211  such that, after the balloon members  206 ,  230  are inflated, the valve  211  may be closed, thereby insuring that the balloons  206 ,  230  do not deflate until such time as desired by the surgeon. Similar to the situation discussed before, the balloon members  206 ,  230  may be slightly inflated during the process of positioning the heart valve  10  around the valve holder  200 ,  240 . Thereafter, when proper positioning is confirmed by the surgeon, the fluid pressure within the housing  202 ,  220  may be increased to fully inflate the balloon members  206 ,  230 , thereby securing the heart valve  10  to the valve holder  200 ,  240 . Thereafter, a handle may be attached to the heart valve holder  200 ,  220  and the heart may be positioned into the proper location in the heart, the distal end  20  of the heart valve  10  may be secured in place by stitching, and the pressure within the balloon members  206 ,  230  may be released and the installation may be completed by the surgeon. Alternatively, both the proximal and distal ends may be secured before releasing the balloon pressure.  
     [0037] In the embodiment depicted in FIGS.  3 A- 3 B, a plurality of balloon members are also employed as a mechanism for holding the stentless heart valve  10  in position. More particularly, as shown therein, the holder  300  is comprised of a housing  302 , a plurality of fluid inlets  304  and three balloon members  306 . The balloon members  306  are coupled to the fluid inlets  304  via a tube  305 , as indicated in FIG. 3B. The length  309  of the heart valve holder  300  may vary, e.g., from approximately 1-3 inches. As before, the housing  302  may be comprised of a variety of materials, such as a plastic or stainless steel material, and the balloon members  306  may be made of silicone or a plastic material. In one embodiment, the tubes  305  are comprised of silicone rubber, and the balloon members  306  may be coupled to the tubes  305  by a variety of techniques, such as wrapping or gluing.  
     [0038] Fluid, such as saline or air, may be introduced into the balloon members  306  via the fluid ports  304 . Although not depicted in the drawing, each of the fluid inlets  304  may be provided with a valve such that fluid flow to each of the balloon members  306  may be individually controlled. Alternatively, all of the fluid ports may be coupled to a single manifold from which the balloons are collectively inflated or deflated. When inflated, the balloon members  306  are sized and adapted to nest within the sinuses of Valsalva in the heart valve  10 , and push against one another, thereby providing a means to securely position the heart valve  10  as required by the surgeon. As before, once the balloon members  306  are inflated, the heart valve  10  may be positioned within the heart, and the surgeon may stitch the proximal and/or distal ends of the heart valve  10  in position. Thereafter, the fluid pressure within the balloon members  306  may be reduced by opening the valves (not shown) coupled to the fluid inlets  304 , and the holder may be withdrawn.  
     [0039] The present application is directed to various embodiments of a heart valve holder. In one illustrative embodiment, a heart valve holder in accordance with the present invention is comprised of a housing, a plurality of hollow members coupled to the housing, each of the plurality of hollow members having a plurality of openings formed therein, and an inlet port coupled to the housing, the inlet port adapted to be coupled to a vacuum source whereby a vacuum pressure may be supplied via the inlet port to the openings in the hollow members. In further illustrative embodiments, the plurality of openings in the hollow members are formed in an exterior surface of the hollow members, and the hollow members are adapted to engage an interior surface of a heart valve. In another embodiment, the plurality of openings on the hollow members are formed on an interior surface of the hollow members, and the hollow members are adapted to engage an external surface of a heart valve.  
     [0040] In other illustrative embodiments, the heart valve holder employs balloon-type structures to assist in holding the heart valve during implantation. In one embodiment, the heart valve holder is comprised of a housing, at least one inlet port coupled to the housing, and at least one balloon member sealingly coupled to the housing and in fluid communication with the inlet port, the balloon member adapted to engage at least a portion of an interior surface of a heart valve when a fluid is supplied to the balloon member via the inlet port. In a more detailed embodiment, the holder is comprised of a balloon member that is positioned around an exterior surface of the housing and sealingly engaged with the housing and in fluid communication with the inlet port, whereby the balloon member is adapted to be inflated by introduction of a fluid through the inlet port and the openings. In yet another illustrative embodiment, a heart valve holder is comprised of a balloon member that is positioned around a bottom surface of the housing and sealingly engaged with the housing and in fluid communication with the inlet port, the balloon member having at least three portions, each of which are adapted to engage, when inflated, at least a portion of a sinus of Valsalva in a heart valve. In a further embodiment, the heart valve holder is comprised of three balloon members, each of which are operatively coupled to and in fluid communication with at least one of the inlet ports, each of the balloon members adapted to engage, when inflated, at least a portion of a sinus of Valsalva of a heart valve and one another.  
     [0041] 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. For example, the process steps set forth above may be performed in a different order. 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.