Abstract:
A heart valve holder-inserter ( 21, 121 ) is designed to facilitate easy implantation of a mechanical heart valve pros-thesis ( 23, 123 ). This holder-inserter, at its distal end, incorporates a pair of diametrically opposed guide members ( 47, 49, 81, 147, 149 ) which extend well beyond the leading edge of the prosthesis and which have exterior surfaces ( 53, 83, 153 ) of substantial dimension that are smoothly curved and proportioned so as to slowly spread the tissue annulus in order to facilitate easy entrance thereinto of the leading edge portion of the mechanical valve body.

Description:
[0001]     This application claims priority from U.S. Provisional Patent Application Serial No. 60/650,778, filed Jan. 27, 2005. 
     
    
       [0002]     The present invention relates to a device for holding and inserting a mechanical heart valve prosthesis and more particularly to a device of this type which facilitates the insertion of an aortic heart valve.  
       BACKGROUND OF THE INVENTION  
       [0003]     The use of surgically implanted mechanical heart valves has become widespread throughout the world and even routine in many countries. There are a variety of mechanical heart valves that have become well-accepted for use in the United States, Europe and Japan as well as in other countries throughout the world, one of which is sold as the On-X heart valve by Medical Carbon Research Institute, LLC, the assignee of this application. This mechanical heart valve prosthesis is shown in U.S. Pat. Nos. 5,545,216, 5,641,324, 5,772,694 and 5,908,452, for example.  
         [0004]     Special tools have been developed to assist in the implantation of mechanical heart valves of this general type. It is important that an effective tool should be capable of holding the valve and facilitating its manipulation at the implantation site in order to properly position it.  
         [0005]     Shown in  FIG. 1  is a prior art valve holder  2  of the type often used for implanting a mechanical heart valve in 1992 and earlier. The valve holder  2  consists of two parts which are generally symmetrical to one another, a first or front part  4  and a second or back part  6 . The prior art valve holder  2  is illustrated in  FIG. 1  in an open condition. The two main body parts of the holder are hinged in some fashion, as example, by a pin  7  or by a living hinge. Two legs  8  and  10  are configured to press outward against an inside wall of an annular valve body when front and rear upper shaft sections  12 ,  14 , respectively, are held together, which is often accomplished by a knotting a flexible tie. The front upper section  2  also has a longitudinal slot  18  which aids in cutting the tie, and it may have a transverse bore through which the tie is threaded and knotted so it remains associated with the inserter and is removed with it following implantation. The distal end of a handle (not shown) is usually received in a cavity or receptacle  19  formed in a cap portion  20  that surmounts the front part  12  of the holder, and the handle is secured in a conventional manner.  
         [0006]     Reference is also made to the above-described inserter in U.S. Pat. No. 5,236,540 entitled “Heart Valve Holder-Rotator”. This patent illustrates and describes a similar inserter where the main body of the holder is formed with a pair of opposed hinged side sections which have depending legs that move toward and away from each other in a manner similar to the two hinged parts described above, but both legs pivot with respect to a central portion of the body. Another heart valve holder of this general type is shown in U.S. Pat. No. 5,443,502.  
         [0007]     Whereas these heart valve holders do securely engage a heart valve prosthesis so as to allow it to be positioned and rotated, oftentimes it is difficult to facilitate the passage of the leading end of the heart valve prosthesis through the annulus in the heart of the patient where the damaged natural valve leaflets were excised. It has been found that this may be a particular problem during the aortic valve replacement when the surgeon must work through the immediately upstream portion of the aorta. Accordingly, improvements in these tools for handling and implanting heart valves have been sought.  
       SUMMARY OF THE INVENTION  
       [0008]     The invention provides a heart valve holder-inserter that includes a main body that is formed with a pair of sloping guide members at its distal end which extend longitudinally in a direction opposite to the direction in which the handle extends. The guide members have tips that are diametrically spaced apart a distance less than the corresponding dimension of a leading portion of a heart valve that would be releasably carried thereon. This design allows the heart valve carried by the holder to be smoothly inserted into the annulus and spread the tissue orifice to facilitate passage therethrough of the leading portion of the heart valve by engaging the tissue over a substantial area and slowly forcing it outward. The holder-inserter is found to be particularly advantageous in inserting an aortic valve, and even more advantageous in inserting an aortic valve having the construction shown in the aforementioned &#39;452 patent where the entrance into the valve body flares outward, thus presenting a rim having an exterior concave, toroidal surface which is designed to seat against the inward facing surface of the heart tissue annulus.  
         [0009]     In one particular embodiment, the invention provides a device for inserting a prosthetic heart valve into an annulus of the heart of a patient, which device comprises a main body proportioned for releasable engagement with a prosthetic valve, said main body having means for connection to a handle for moving and positioning the main body and the valve engaged therewith; and said main body also having two sloping guide members extending longitudinally from said main body in a direction generally opposite that in which said handle extends, which guide members have tips which are diametrically spaced apart a distance less than a corresponding dimension of a leading portion of a heart valve that would be releasably carried thereon, with outward-facing surfaces of said guide members sloping from said tips outward to about a diameter of the valve leading portion, whereby passage of the leading portion of the valve prosthesis into an annulus, from which the patient&#39;s defective valve leaflets have been excised, is facilitated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a prior art tool for holding and inserting a mechanical heart valve prosthesis.  
         [0011]      FIG. 2  is a perspective view of a heart valve holder-inserter embodying various features of the present invention.  
         [0012]      FIG. 3  is a cross-sectional view showing a mechanical heart valve prosthesis of the type generally marketed as the On-X aortic valve and disclosed in the &#39;452 patent.  
         [0013]      FIG. 4  is a front view of the holder-inserter shown in  FIG. 2 .  
         [0014]      FIG. 5  is a bottom view of the holder-inserter shown in  FIG. 4 .  
         [0015]      FIG. 6  is a left side view of the holder-inserter shown in  FIG. 4 .  
         [0016]      FIG. 7  is a perspective view of an assembly of the holder-inserter shown in  FIG. 2  with a mechanical heart valve engaged thereon.  
         [0017]      FIG. 8  is a front view of the assembly shown in  FIG. 7 .  
         [0018]      FIG. 8A  is a fragmentary enlarged view of  FIG. 8 .  
         [0019]      FIG. 9  is a side view of the assembly shown in  FIG. 7 .  
         [0020]      FIG. 10  is a fragmentary view similar to  FIG. 8A  showing an alternative embodiment of a heart valve holder-inserter embodying various features of the invention assembled with the  FIG. 3  heart valve.  
         [0021]      FIG. 11  is a fragmentary left side view of the assembly shown in  FIG. 10 .  
         [0022]      FIG. 12  is a perspective view of an assembly of an alternative embodiment of a holder-inserter shown with a valve similar to that sold by St. Jude Medical, Inc. carried thereon.  
         [0023]      FIG. 13  is a perspective view of the assembly shown in  FIG. 12  from another angle.  
         [0024]      FIG. 14  is a front view of the assembly shown in  FIG. 12 .  
         [0025]      FIG. 15  is a side view of the assembly shown in  FIG. 14 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     The invention provides a device  21  which serves as a holder-inserter for implanting a mechanical heart valve prosthesis in an annulus in the human heart. The principles embodied in the device  21  are effective in creating a useful holder-inserter suited for implanting a wide variety of mechanical heart valves, particularly bileaflet heart valves; however, the preferred embodiment of the device that is shown in the drawings is proportioned and shaped to facilitate the implantation of the On-X heart valve  23 , a cross-sectional view of which is illustrated in  FIG. 3 . This valve  23  employs a pair of leaflets  25  that are pivotally mounted on a valve body or orifice ring  27 , as described in detail in the earlier mentioned U.S. Pat., which valve body  27  has an outwardly flaring entrance end  29 . The illustrated valve  23  is designed to be inserted as an aortic valve replacement where it will be positioned so that the concave, generally toroidal exterior surface of the curved entrance end  29  lies in contact with the tissue annulus from which leaflets of the defective natural valve were excised. The implanted prosthesis is secured in place by suturing through a sewing ring  31  which is affixed to a central exterior region of the valve body  27 , with sutures being secured by pledgets which are positioned on the heart side of the annulus, i.e. facing the left ventricle of the heart.  
         [0027]     The holder-inserter device  21  has a main body  33  which comprises two hinged parts that are movable relative to each other. These are arbitrarily referred to as a front part  35  and a rear part  37 . The body can be made of any acceptable material as well known in this art, but will usually be molded from polymeric material capable of being sterilized, such as nylon, Teflon, Delrin or polysulfone. The two parts  35 ,  37  may be molded separately and suitably joined at a pivot or hinge point therebetween. Alternatively they may be molded as a single integral piece being interconnected by a living hinge. The front or left hand part  35  (as oriented in  FIG. 4 ) is formed with an upper section  39  and a depending leg  41 . The rear or right hand part  37  is formed with an upper section  43  and a depending leg  45 . The two legs  41  and  45  have the same construction, being mirror images of each other; the recessed upper portions of the legs constitute a groove proportioned to receive valve body  27  to be carried thereupon.  
         [0028]     The main body  33  is molded as two separate pieces with a hinge point therebetween which is established in any suitable manner. For example, a separate hinge pin can be seated in bores provided in both parts  35 ,  37 , or short stub pivots can be seated in receptacles molded in the mating part. The two parts will pivot between their engaging orientation (as illustrated in  FIGS. 2 and 4 ) and a release orientation (such as that shown in the  FIG. 1 ) wherein one leg  45  has swung closer to the other leg  41  so as to release a mechanical heart valve with which it was earlier engaged.  
         [0029]     The heart valve holder-inserter  21  generally resembles the prior art device depicted in  FIG. 1  except for the incorporation of a pair of sloping guide members  47 ,  49  which are respectively located at the lower ends of the legs  41 ,  45  and formed integrally therewith. Each guide member has a transverse surface or a flange  51  formed at its upper end against which the leading edge  29  of the mechanical heart valve seats; this engagement secures the valve in place on the holder-inserter  21  when the two body parts  35 ,  37  are in the engaging orientation, as depicted in  FIG. 4  and  FIG. 7 , for example.  
         [0030]     The guide member  49  is formed with a sloping exterior surface  53  that smoothly extends from the outer edge of the flange  51  down to a tip  55 . When the two legs  41 ,  45  are in their engaging position, the outer edge of the transverse surface  51  lies close to the outer edge of the rim  29  of the heart valve, as best seen perhaps in  FIG. 8  where the inserter  21  is illustrated with a heart valve  23  engaged thereon. The longitudinally sloping surface  53  extends smoothly over the entire distance from the edge of the ledge to the lower or bottom tip  55 , which is described as being a continuous curve, i.e. having no reentrant section. In  FIG. 8 , the outer edges of the tips  55  are spaced apart at their greatest distance, a distance which is substantially less than the diameter of the rim  29  of the heart valve at its leading edge, preferably a distance between about 30% and 80% of the diameter of the rim and more preferably between about 50% and 65% of the diameter of the rim. Preferably these outer edges are arcs which lie on a circle which has its center on the longitudinal axis of the inserter  21 ; however, such is not a requirement as explained hereinafter.  
         [0031]     Basically the exterior surface of the guide members  47 ,  49  may be any surface curved in a plane perpendicular to longitudinal axis. It is preferably curved both in the plane perpendicular to the longitudinal axis of the heart valve inserter and in the plane parallel to the longitudinal axis, as is depicted in  FIGS. 2 and 4 - 9 ; however it may be curved only in the plane perpendicular to longitudinal axis, as shown in FIGS.  10  and  11  where the surface  83  is a section of a cone. The exterior surfaces  53 , which are preferably double-curved as illustrated in  FIG. 4 , are more preferably sections of a surface of revolution. They may be sections of a sphere or of an ovoid or any generally similar shape which might be referred to as spheroidal or ovoidal. By ovoidal is meant ellipsoidal, paraboloidal or the like, with ellipsoidal being most preferred. Although from the standpoint of symmetry it is preferable that both guide members  47  and  49  have surfaces  53  which are sections of the same surface of revolution, it should be understood that the guide members, when they are in the ultimate engaging orientation shown in  FIG. 8 , may not lie precisely on the same surface of revolution because their orientation may be somewhat askew with regard to each other, e.g. because of tolerances or other such factors.  
         [0032]     As best seen in  FIG. 5 , at the upper ends of the guide members where the flanges  51  are located, their circular outer edges should subtend an arc of at least about 60° and more preferably an arc between about 75° and about 105°. The upper size limitation on the arc is determined by the amount of clearance which exists in the heart valve to be implanted, because as apparent from  FIG. 3 , the guide members need to pass between the leaflets  25  and the interior wall of the valve body  27 . An arc of at least about 60° at the upper regions is felt to be sufficient to adequately spread the tissue orifice to facilitate the easy entry of the valve into position. Hollows  58  in the interior surfaces ( FIG. 2 ) also provide clearance for the leaflets.  
         [0033]     Side edge surfaces  59  of the guide members  47 ,  49 , as best seen in  FIGS. 5, 6  and  7 , are not longitudinal but are canted; they are preferably canted at a slight angle of at least about 5° and preferably at least about 10°. Thus, as can be seen from  FIGS. 5 and 6 , although the respective side surfaces  59  of the guide members  47 ,  49  are co-planar, they do not lie in a plane parallel to the longitudinal axis, but they are offset so that there is a taper towards the longitudinal axis as these side surfaces extend toward the tips of the guide members. The flanking side edge surfaces of the guide members (which are identified in  FIGS. 5 and 6  by the reference numeral  59 ) more easily enter the annulus because of this about 5°-10° offset; moreover, these surfaces  59  exert an outward camming action with regard to both the tissue and any pledglets being used to retain sutures on the heart side of the orifice when the holder-inserter carrying the heart valve is rotated after it has been inserted sufficiently into the excised orifice so that the guide members are in contact with the tissue.  
         [0034]     The longitudinal length of the guide members is also considered to be important so that further insertion of the guide members, after contact with the tissue is made, exerts a relatively slow and smooth outward deflection of the tissue. In this respect, it is preferred that the longitudinal length of the guide members, i.e., the distance A in  FIG. 8 , should be between about 20% and about 80% of the diameter of the leading portion of the valve body, more preferably between about 30% and about 40% of the diameter of the valve body circular rim. The longer the length of the guide member, the more gradual may be the radius of curvature of the exterior surfaces which in turn results in a smoother spreading of the annulus. When the valve is close to being in its fully inserted position, it is normal that the inserter be rotated, and it is during this rotation that the side edge surfaces  59  cam outward regions of the tissue annulus that were not initially in contact with a guide member exterior surface.  
         [0035]     It can also be seen from  FIG. 5  that the edge from one corner C ( FIGS. 2 and 5 ) of a tip to the opposite corner C would be an arc of slightly less than the arc at the upper edge of the surface at the edge of the flange  51  as a result of the canting of the side surfaces  59 . Moreover, to avoid a sharp edge at the distal end, the tip ends of the guide members are flattened creating narrow flat surfaces  60 . The interior surfaces of the guide members, which are recessed to provide the hollows  58  facing each other, further avoid interference with the leaflets of the bileaflet valve.  
         [0036]     When the holder-inserter  21  is in engagement orientation with a bileaflet heart valve  23 , as depicted in  FIG. 7 , the upper sections  39  and  43  of the two main body parts have been pivoted into abutting engagement with each other. The upper sections include an annular groove  61  about the periphery wherein a flexible tensile member  63  is routed and tied to lock them in this abutting position. The tensile member  63 , usually a short length of suture cord, is preferably threaded through a transverse bore  64  in the upper section  39  and knotted.  FIG. 4  shows a longitudinally extending slot  65  which facilitates the surgeon cutting the tensile member  63  to release the engagement and permit the removal of the holder-inserter after the heart valve  23  has been implanted and at least preliminarily sutured into the desired orientation in the wall of the heart.  
         [0037]     The front portion  35  of the main body also includes a cap section  67  wherein a top cavity  69  is formed that may extend completely through the body (as indicated in  FIG. 5 ). The upper end of the cavity  69  is shaped so as to interengage with a cooperating member formed at the distal end of a handle (not shown) as well known in this art. The holder-inserter  21  is designed such that it would be commonly packaged together with the heart valve and sterilized prior to shipment to a hospital or other facility. When ready for use, the package would be opened in the operating room, and a sterilized handle would be mated with the assembly via the cavity  69  at the upper end of the holder-inserter once the operation is ready to begin, or later when the surgeon has selected the precise size of heart valve to be implanted. During shipment, the assembly is stably supported in packaging by a C-shaped clip that is received in the pair of side slots  73  provided in the main body, as best seen in perhaps  FIG. 9  and as generally known in this art.  
         [0038]     After the leaflets of the defective natural valve have been excised by operating through the aorta, sutures are placed about the annulus, sometimes with supporting pledglets disposed on the left ventricle side of the annulus, and spaced around the circumference thereof. The surgeon would then insert the holder-inserter  21  with the engaged valve  23  so that the guide members  47 ,  49  extend through the annulus. This insertion movement causes the sloping surfaces  53  to engage the edge of the tissue annulus, causing it to be smoothly and slowly expanded outward and guiding entry of the leading edge of the valve body into the orifice. The surgeon then rotates the device to smoothly spread the remaining circumference of the tissue annulus outward in arcuate locations where it was not initially in contact, to align the bileaflet valve as desired with respect to the left ventricle. The rotation causes the side edges surfaces  59  not only to cam the tissue outward, but also to engage edges of any pledglets that might be located there to displace them so they will not possibly lie between the valve body exterior surface and the raw edge of the tissue. An appropriate corner blend (not shown) between the surfaces  53  and  59  is preferably included to facilitate this displacement. As a result, the engaged heart valve  23  is moved smoothly into its desired orientation with the raw edge of the tissue annulus lying in abutment against the concave, generally toroidal exterior surface of the leading edge  29  of the heart valve  23 . At this time, the surgeon sutures the valve at least partially in place using curved suture needles which are passed through the sewing ring  31  and then tied off, as well known in this art. The surgeon can then cut the tensile member  63  where it passes over the cutting slot  65  so as to release the engagement at the upper end of the main body; this allows the leg  45  at the bottom of the rear part  37  to pivot freely and disengage from its contact with the interior surface of the valve body. Slight movement of the inserter to the right in  FIG. 8  disengages the leg  41  from its contact; this allows the holder-inserter to be withdrawn straight away, carrying with it the cut flexible member  65  which is retained in the transverse bore  64  in the cap section.  
         [0039]     Depicted in  FIGS. 10 and 11  is an alternative embodiment of a holder-inserter wherein, instead of using guide members that have the double curved exterior surfaces, smooth sloping surfaces are provided by forming each of the guide members  81  with surface  83  which is a section of a cone. Except for this change, the guide members  81  resemble the guide members  47 ,  49  previously described. They have similar flat bottom tips  85  which have outer edges that are similarly spaced apart and oriented as described above.  
         [0040]     Illustrated in  FIGS. 12-15  is an alternative embodiment of a holder-inserter  121  which is designed to support a different mechanical heart valve; it is shown as carrying a mechanical heart valve of the general type as has been sold for several decades by St. Jude Medical, Inc. The components of the holder-inserter  121  are given reference numerals the same as the holder-inserter  21  plus  100 . Accordingly, it should be understood that statements made earlier with respect to such a corresponding part are equally applicable to the part bearing the corresponding reference numeral in  FIGS. 12-15 .  
         [0041]     This alternative embodiment of the device  121  that is shown is proportioned and shaped to facilitate the implantation of a mechanical heart valve  123 , similar to that which is marketed by St. Jude Medical, Inc. and shown in U.S. Pat. No. 4,276,658. This valve  123  likewise employs a pair of leaflets  125  that are pivotally mounted on a valve body or orifice ring  127 . The illustrated valve  123  is designed to be inserted as an aortic valve replacement where it will be positioned so that a pair of semicircular extensions  128  at its entrance end protrude toward the left ventricle in the annulus from which leaflets of the defective natural valve were excised. The implanted prosthesis is secured in place by suturing through a sewing ring  131  which is affixed to a central exterior region of the valve body  127 , with sutures being secured by pledgets which are positioned on the heart side of the annulus, i.e. facing the left ventricle of the heart.  
         [0042]     The holder-inserter device  121  has a main body  133  which comprises two hinged, relatively movable parts, a front part  135  and a rear part  137 . The front or left hand part  135  (as oriented in  FIG. 14 ) is formed with an upper section  139  and a depending leg  141 . The rear or right hand part  137  is formed with an upper section  143  and a depending leg  145 . The two legs  141  and  145  have the same construction, being mirror images of each other, with a pair of integral, sloping guide members  147 ,  149  being located at their lower ends. Each guide member has a transverse surface or a flange  151  formed at its upper end against which the entrance end  129  of the valve seats, in the groove provided in the legs  141 ,  145 ; this end is the leading edge of the heart valve during implantation from the aorta. Engagement in the groove secures the valve in place on the holder-inserter  121  when the two body parts  135 ,  137  are in the engaging orientation, as depicted in the drawings.  
         [0043]     A sloping exterior surface  153  of the guide member  147  smoothly extends from the outer edge of the flange  151  down to a tip  155 . When the two legs  141 ,  145  are in their engaging position, the outer edge of the transverse surface  151  lies close to the outer edge of the rim of the heart valve entrance end  129 . The longitudinally sloping surface  153  extends smoothly as a continuous curve over the entire distance from the edge of the ledge to the lower or bottom tip  155 . As best seen in  FIG. 14 , the outer edges of the tips  155  are again spaced apart at a distance which is substantially less than the outer diameter of the rim  129  of the heart valve.  
         [0044]     The upper ends of the guide members where the flanges  151  are located have circular outer edges that again each subtend an arc of about 75° and about 105°. Hollows  158  in the interior surfaces also provide clearance for the leaflets.  
         [0045]     Side edge surfaces  159  of the guide members  147 ,  149  are again preferably canted at a slight angle of at least about 5° and preferably at least about 10°. Again, the preferred longitudinal length of the guide members, i.e., the distance B in  FIG. 12 , should be between about 20% and about 80% of the diameter of the leading edge of the valve body  127 , more preferably between about 30% and about 40% of the diameter of the outer circular rim surface of the valve body  127 .  
         [0046]     The remainder of the construction of the holder-inserter  121 , primarily the upper portion thereof, is the same as that hereinbefore described for the holder-inserter  21 . The bileaflet heart valve  123  would be installed and released in the manner described hereinbefore. Similarly, the surgeon would insert the holder-inserter  121  with the valve  123  carried thereon so that the sloping guide members  147 ,  149  extend through the annulus from which the defective leaflets of the natural valve have been excised. Again, the sloping surfaces  153  would cause the edges of the tissue annulus to be smoothly and slowly expanded outward, guiding the entry of the leading edge of the valve body  127  into the orifice. Then, the surgeon would rotate the device to smoothly spread the remaining circumference of the tissue annulus outward, and to align the bileaflet valve as desired with respect to the left ventricle. Once the desired, correct orientation has been attained, the surgeon would suture the valve at least partially in place and then, as earlier described, cut a tensile member to release the engagement at the upper end of the main body of the two portions of the holder-inserter, allowing the leg  145  at the bottom of the rear part  137  to pivot freely and disengage so that the holder-inserter  121  can be withdrawn straightaway.  
         [0047]     Thus, it should be appreciated that a holder-inserter for a mechanical heart valve prosthesis has been provided that fully meets the objectives stated above. However, although preferred embodiments have been illustrated and described, which constitute the best mode presently known to the inventors for carrying out this invention, it should be appreciated that various changes and modification as would be obvious to one having the ordinary skill in this art may be made without departing from the scope of the invention which is defined in the claims appended hereto. In this respect, although the description has been directed to the implantation of an aortic heart valve, it should be understood that similar advantages are obtained when the holder-inserter is used to insert a valve in the mitral position, for example. The disclosures of all of the previously enumerated U.S. Pats. are expressly incorporated herein by reference.  
         [0048]     Particular features of the invention are emphasized in the claims which follow.