Abstract:
A holder for prosthetic heart valves including an annular base and prosthetic valve leaflets extending between commissure regions oriented axially with respect to the base. The holder includes a grip element from which a plurality of arms extend for supporting the prosthetic heart valve in an intermediate position between the commissures. Protecting formations extend radially with respect to the grip element to protect the commissure regions. The grip element includes a first rotational element for coupling to a handle and at least one second coupling element for coupling the grip element of the holder to a support element thereby impeding its rotation.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to holders for implantable devices and was developed with particular attention paid to holders for prosthetic heart valves. 
       BACKGROUND 
       [0002]    Holders are used for supporting an implantable device, such as a prosthetic heart valve, before and during implantation. The holder may, for example, support the prosthesis (1) during production of the prosthesis, while the prosthesis is subjected to phases of immersion in treatment liquids (e.g., for the removal of undesired chemical residues from the prosthetic valve leaflets of biological tissue with procedures such as that described in EP-B-0 401 199), (2) after the valve has been inserted into its sterile package, where it is usually kept immersed in a storage liquid, and (3) during implantation, when the holder is coupled to a handle to enable the surgeon to implant the valve. 
         [0003]      FIG. 1  of the attached drawings shows an exemplary prosthetic tissue heart valve. One example of such a valve is disclosed in EP-A-0 155 245 and EP-B-0 515 324, both of which are hereby incorporated by reference. The valve, which may be either “stented” or “stentless,” typically includes: an annular base region B, having an overall circular shape for suturing onto the valve annulus, and a series of prosthetic valve leaflets V that usually include a plurality of commissure regions C oriented in a generally axial direction with regard to the base region B of the valve. The proximal edges of the prosthetic valve leaflets are configured to mate when the prosthetic valve is the closed position, thus impeding blood flow through the valve. The mating leaflet surfaces thus define coapting edges of the leaflets in the closed position. Typically, in an effort to reproduce the structure of natural heart valves (e.g., aortic heart valves), the prosthetic valve has three commissures C between which three prosthetic valve leaflets V extend. The commissures C are thus generally spaced at 120° apart about the valve circumference. 
         [0004]    Valve holder known in the art typically include a central grip element from which three arms (or struts) branch out and extend a sufficient distance to approximately envelope the profile of the valve. These arms are configured to attach to the valve at base region B. Often, the distal ends of the arms are connected together by a circular structure, which provides a support for the base region B of the valve. Typically, these arms extend downwardly adjacent the commissures C of the valve, so as to protect the commissures C during valve implantation. 
         [0005]    These types of holders, which result in substantial contact between the holder and the prosthetic tissue valve, can have an undesirable impact on the tissue valve if such contact continues for a substantial length of time. Thus, there is a need in the art for a holder design that minimizes this contact. 
       SUMMARY 
       [0006]    The present invention, according to one embodiment, is a holder for a prosthetic heart valve, the valve including an annular base and a plurality of leaflets extending between commissure regions. The holder includes a grip element, a plurality of arms extending from the grip element and configured for supporting the prosthetic heart valve in an intermediate position between the commissure regions, and a plurality of commissure formations extending from the grip element. The formations are configured to extend radially from the grip element to cover an outward most point of the commissure regions. 
         [0007]    The present invention, according to another embodiment, is a holder for a prosthetic heart valve, the valve including an annular base and a plurality of leaflets adapted to mate at coapting edges. The holder includes a grip element and a plurality of formations extending radially from the grip element, wherein the formations are configured to protect the coapting edges. 
         [0008]    While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic view of a prosthetic tissue heart valve, as is known in the prior art. 
           [0010]      FIG. 2  is a general perspective view of a holder, according to one embodiment of the present invention, coupled to a prosthetic valve of the type shown in  FIG. 1  mounted onto it, and 
           [0011]      FIGS. 3-5  illustrate different ways of using the holder described here. 
       
    
    
       [0012]    While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims 
       DETAILED DESCRIPTION 
       [0013]      FIGS. 2-5  show a holder  10  configured for use with a prosthetic tissue heart valve of the type shown in  FIG. 1 . As shown in  FIG. 2 , the holder  10  includes a grip or hub element  12 , provided with coupling formations (further described below) and a plurality of arms  14  (e.g., three in number) that branch in a radial and distal direction from the grip element  12  to support the base region B of the prosthetic valve. As shown, the distal ends  16  of the arms  14  are linked together by a circular annular support formation  18 , which is configured to support the base region B. 
         [0014]    According to one embodiment, the support formation  18  includes an annular formation different from the continuous annular formation shown in  FIG. 2 . The support formation  18 , for example, may include successive, distinct and separate stretches, of an overall annular structure, each stretch coupled to the distal end  16  of the respective arm  14 , according to a general cross-bow-shaped configuration. 
         [0015]    The holder  10  typically includes three arms  14 , configured to extend between each of the three prosthetic valve commissures C. According to various embodiments, the holder includes more or less than three arms  14 . As shown in  FIG. 2 , the holder  10  is suited to be coupled to the valve in such a manner that the arms  14  extend in an intermediate position between the commissures C. According to one embodiment, the arms  14  extend in an approximately central position with respect to the valve leaflets V, each of which presents a general eye-lid-like shape. The arms  14  are thus disposed so as to avoid contact with the commissures C. The valve V may be fastened onto the holder  10 , according to any known technique, by employing suture threads  24  that extend from holes  25 ,  26  provided in the structure of the holder  10  and are passed around the valve in correspondence with the base region B. 
         [0016]    In one embodiment, the holder  10  consists of a single piece of moulded material, of a type approved for use in the surgical field. In one embodiment, for reasons further described below, the material is a transparent or translucent material (e.g., polycarbonate). The terms “transparent” or “translucent” as used herein indicate a material that, due to its nature and/or morphology (thickness), does not impede the view of an element immediately below the material. 
         [0017]    The valve  10  further includes canopy or commissure formations  22  that extend from the grip element  12  (e.g., from the root or proximal region of the arms  14 ). According to various embodiment, each of the canopy formations  22  projects in a radial direction with respect to the principal axis X 10  of the holder  10  by an amount substantially sufficient to cover the radial dimension of the valve V. In other words, the distal end of each canopy formation  22  extends a sufficient distance to cover a respective commissure C. 
         [0018]    According to some embodiments, the general V-shaped configuration of each canopy formation  22  is coordinated one to the next in such a manner that the set of the three canopy formations  22  forms, in correspondence with an ideal plane normal to the axis X 10 , a triangular structure. This triangular structure may have one or more blunt or cropped vertices. According to other embodiments, the formations  22  have alternative profiles. The formations  22 , for example may have a generally finger-nail or petal shape configurations. 
         [0019]    The canopy formations  22  protect the commissures C so as to impede, during implantation of the valve, the accidental and undesired extension of suture stitches in correspondence with the commissures C. The formations  22  protect the commissures C and serve to warn the surgeon against an adverse suture trajectory. The presence of the canopy formations  22 , however, will not hinder the surgeon&#39;s view of the commissures C, if the canopy formations  22  are made of transparent or translucent material, such as for example polycarbonate. In this way, the commissures C are effectively protected against an undesired suturing action, but the commissures are nevertheless clearly visible to the surgeon. Preferably, the formations  22  are configured to cover or protect the entirety of the “coapting edges” of the prosthetic valve leaflets (as previously defined). 
         [0020]    Preferably, according to various embodiments, the arms  14  are of sufficient length, and extend a sufficient distance in a downward direction, to allow for a space or gap between the formations  22  and the upper portions of the valve commissures C. This space minimizes or avoid contact between the formations  22 , the coapting edges of the valve leaflets and the commissures C, which in turn minimizes or prevents exposure of the prosthetic tissue valve V to the material of the holder  10 . This, in turn, avoids those undesired phenomena due to the pressure applied on the prosthetic tissue valve by the contact with the holder, as was described above. 
         [0021]    During implantation, after suturing the valve (at least in a temporary manner) to the annulus, the surgeon may cut those stitches that fasten the valve onto the holder  10 , such that when the surgeon separates the holder  10  from the valve, these fastening stitches will be removed with the holder  10  without running the risk of remaining in an undesired manner on the valve or at the implantation site. 
         [0022]    According to some embodiments, the canopy formations  22  include, on their “proximal” face (i.e., the face directed away from the valve), ribs  27  which are in relief with regard to the general plane of the canopy formation  22 . The ribs  27  are configured such that the fastening stitches applied using the openings  25  and/or  26  extend in a bridge-like fashion from the face of the canopy formations  22 . This creates a space between the suture and the face, which facilitates removal by the surgeon. 
         [0023]    The sequence of  FIGS. 3 ,  4  and  5  shows, in schematic form, three successive operational conditions in which the holder  10  performs the function of supporting the valve.  FIG. 3  shows the function in which the holder  10  is supporting the valve mounted onto it in a treatment bath during the production phase of the valve.  FIG. 4  shows the holder  10  used to support the valve inside its sterile package, where the valve is once again usually immersed in a liquid, consisting of a storage bath. Lastly,  FIG. 5  shows the holder  10  fixed to the distal end of a handle M, which is used by the surgeon to position and hold the valve on its insertion annulus during the implantation procedure. 
         [0024]    These three different conditions of use must in general meet different requirements. In the condition shown in  FIG. 3 , it must be possible to transfer the holder  10  (and the valve mounted onto it) with relative ease, employing gripping devices, possibly robotic, thus without performing particularly complex movements. In the condition of use in  FIG. 5  (implantation phase) it is imperative to ensure as solid and precise as possible a connection between the holder  10  (and the valve) and the handle M. 
         [0025]    The condition shown in  FIG. 4 , on the contrary, represents an intermediate situation between the situation in  FIG. 3  and the situation in  FIG. 5 . In particular, it is desirable that the holder  10 , with the valve mounted onto it, can be inserted with relative ease into the sterile package, and that likewise it can be extracted with ease, in a precise and reliable way from the package, coupled to the handle M for subsequent use by the surgeon: all of this with a sequence of operations to extract it from the package and mount it onto the handle that are normally performed at the operating field by a surgical technician. 
         [0026]    The solution described herein reconciles these different requirements, by fitting the grip element  12  with two coupling systems. 
         [0027]    A first coupling system consists of a threaded rod  30  that projects at the opposite end of the grip element  12  with regard to the arms  14 . The threaded rod  30  enables the holder  10  (and the valve that is mounted onto it) to be coupled to the handle M with a movement that is simple to perform, that is operating such that the handle M is screwed onto the threaded rod  30  of the holder  10 . At the same time, this screw-thread coupling is very solid and precise. It is possible to operate in such a manner that this screw-thread coupling has an end-of-run limit position that is exactly predetermined from the angular standpoint, such that the valve will be in a precisely-determined angular position with respect to, for example, a landmark provided on the handle M. 
         [0028]    The screw-thread coupling described might also be made in a complementary manner, that is by providing, at the end of the grip element  12  of the holder  10 , a female screw-thread into which a threaded rod provided on the handle M could be screwed. The solution illustrated here (threaded rod on the holder  10  and not on the handle) appears however at the moment to be preferable since it avoids having to produce a recessed part (the female screw-thread) on a component, namely the holder  10 , destined to be involved in the sterile packaging cycle of the valve. 
         [0029]    Additionally, as shown in  FIG. 3 , the grip element  12  includes one or two notches  34  in a generally proximal position with respect to the screw-thread coupling element  30 . The notch or notches  34  enable the grip element  12  of the holder  10  to be coupled with a corresponding support element through a coupling mechanism that in general may be defined as “through lateral translation with blocking of the rotation movement” of the grip element  12 . In other words, the coupling mechanism comes about by effect of the lateral translation of the grip element  12 , thus in the sense of a lateral translation with respect to the principal axis X 10  of the holder  10 , and at the same time impedes rotation of the grip element  12  (and of the holder  10  overall) around the axis X 10 . 
         [0030]    The notch or notches  34  allow insertion of the grip element  12  into a groove-like reception element such as the element K shown in both  FIG. 3  and  FIG. 4 . As shown in  FIG. 4 , the groove-like grip element K may simply comprise a notch in a discoid element D that rests on the rim of the sterile package P of the valve. This package generally presents in the form of a jar with a cup-like body and a screw-cap T (shown in dotted lines in  FIG. 4 ). 
         [0031]    A similar grip element may also be easily adopted for use in packaging and treatment of the valve, either in the form of a groove-like incision like that shown in  FIG. 5 , or again in the form of two jaws with a straight grip formation capable of penetrating into the groove or grooves  34 . In the embodiment included a jaw, this coupling resists rotation of the grip element  12  about the axis X 10 , but does not require a lateral coupling movement of the type described above. 
         [0032]    It follows that, without prejudice to the underlying principle of the invention, the details and embodiments may be varied, even significantly, with regard to what has been described and shown by way of non limiting example, without thereby departing from the scope of the invention, as is defined in the annexed claims. Likewise, various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.