Abstract:
Apparatus and methods for securing heart valve repair or replacement prostheses in or near the heart. The apparatus and methods are particularly well suited for traditional surgery or minimally invasive surgery. The invention secures a heart valve repair or replacement prosthesis in place while lowering surgical exposure. The invention improves the ease of implantation because it reduces the number of surgical knots a clinician would normally tie in the limited space in and around the heart.

Description:
RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 61/497,313, filed Jun. 15, 2011. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to heart valve surgery and more particularly to devices and methods for anchoring prostheses inside or near the heart. 
     BACKGROUND OF THE INVENTION 
     Many different surgical procedures benefit from anchors used to secure prostheses to tissue at various locations in the body. One area where this is true is in the field of heart valve repair. Heart valve repair is a procedure to fix or replace a damaged heart valve or tissue around the heart valve. 
     There are four main heart valves in the heart: the aortic, mitral, pulmonary, and tricuspid. The aortic valve is located at the outflow end of the left ventricle and empties into the aorta. The mitral valve is located at the outflow end of the left atrium and empties into the left ventricle. The pulmonary valve is located at the outflow end of the right ventricle and empties into the pulmonary artery. The tricuspid valve is located at the outflow end of the right atrium and empties in the right ventricle. 
     Stenosis is a common affliction that can negatively affect the function of a heart valve. Stenosis is when a heart valve becomes harder due to calcification that decreases the heart valve effectiveness. A typical treatment for a stenosed heart valve is heart valve replacement also known as valvuloplasty. One way a heart can be replaced is by cutting out the diseased valve and suturing a prosthetic valve in its place. 
     Another problem that can negatively affect the function of a heart valve is deformation of the heart valve annulus. A deformed heart valve annulus can reduce leaflet coaptation causing leakage, also known as regurgitation. Typically, clinicians use an annuloplasty ring to treat a deformed heart valve annulus. The annuloplasty ring can be sutured in place such that the annulus takes the shape of the annuloplasty ring. Both valvuloplasty and annuloplasty conventionally involve tying suture knots in order to secure a prosthesis in or near the heart. 
     Clinicians can perform traditional open heart surgery to repair a defective valve or can utilize a minimally invasive or transcatheter technique. Traditional open heart surgery involves administering anesthesia and putting a patient on cardio-pulmonary bypass. A clinician cuts open the chest to access the heart. Then the clinician cuts out the defective native valve leaflets leaving the annulus in place. The clinician places sutures in the annulus or other tissue near the heart valve. The free ends of the sutures are threaded through a sewing cuff on the heart valve prosthesis. The clinician “parachutes” the heart valve prosthesis into place by sliding it down the sutures until it rests on the annulus. To secure the prosthesis a clinician can tie each suture free end to another free end to prevent the sutures from backing out. This prevents the prosthesis from migrating away from the annulus. Normally, this process entails about 4-8 knots on each of the 12-20 sutures used per implant. Thus, the number of suture knots can be quite large. 
     What was just described was a procedure for implanting a prosthetic valve. To implant an annuloplasty ring a similar procedure is followed except that the native valve is typically left in place. The annuloplasty ring is sutured in place to reshape the valve annulus and improve native heart valve leaflet coaptation. 
     Minimally invasive and transcatheter techniques may also be used. Normally a collapsible surgical prosthesis is used with minimally invasive or transcatheter procedures. To implant the prosthesis using a minimally invasive technique, a clinician makes a small incision in the chest and uses special tools to pass the heart valve repair prosthesis through the incision. An example of a minimally invasive heart valve repair procedure is transapical aortic valve replacement. In a transcatheter technique, a clinician passes a catheter through a patient&#39;s vasculature to the desired location in the heart. Once there, the clinician deploys the surgical prosthesis and uses tools which can be passed through a patient&#39;s vasculature to secure the prosthesis in place. An example of a transcatheter heart valve repair procedure is transfemoral aortic valve replacement. 
     Within the prior art there exists a need for devices and methods that reduce the time required to secure a heart valve repair prosthesis in place. Currently a clinician must tie a multitude of knots in sutures which can take a great deal of time. This lengthens the time a patient is on cardio-pulmonary bypass and under anesthesia. Thus, any reduction in surgical time that a patient undergoes would be beneficial. 
     Additionally, there exists a need to make it easier to secure a heart valve repair prosthesis in place. Currently, a clinician must work in the limited space near the heart to tie knots in sutures. This is a cumbersome process that benefits from a clinician of great dexterity and patience. In a minimally invasive or transcatheter surgery, the clinician must use tools that can be passed through a small incision, thus making the tying of knots even more difficult. Therefore, any improvement in ease of use would be beneficial. 
     Further still, there exists a need to increase the robustness of the attachment of a heart valve repair prosthesis. In order for the prosthesis to achieve maximum effectiveness, it must be coupled to the tissue around the heart valve and form a tight seal. For example, in the case of a prosthetic heart valve, the sewing ring must seal against the heart valve annulus such that no blood leaks around the outside of the sewing ring. Any leaks would decrease the effectiveness of the prosthetic valve. Thus, an increase in the robustness of the bond formed between the heart valve repair prosthesis and the annulus would be beneficial. 
     SUMMARY OF THE INVENTION 
     The present invention provides new apparatus and methods for securing heart valve repair or replacement prostheses in or near the heart. The apparatus and methods are particularly well suited for traditional surgery or minimally invasive surgery. The invention reduces the number of surgical knots thus reducing surgical time and exposure. The invention improves the ease of implantation because it reduces or eliminates the surgical knots a clinician would normally tie in the limited space in and around the heart. Additionally, embodiments of the invention provide a more robust attachment for heart valve repair or replacement prostheses. 
     In accordance with one exemplary embodiment, a knotless heart valve prosthesis includes a lower segmented ring having an implanted size that can be collapsed to a smaller size for passage through an annulus. An upper securing ring connects to a prosthetic heart valve. A plurality of elongated flexible connection members extend upward from the segmented ring through mating apertures formed in the securing ring so as to couple the two rings together and clamp a valve annulus therebetween, thereby securing the heart valve to the valve annulus without sutures. The prosthesis may further have a plurality of protruding members that extend generally radially outward from the lower segmented ring that help anchor the heart valve to the valve annulus. Desirably, the lower segmented ring includes rows of teeth on an upper surface thereof that help anchor the heart valve to the valve annulus. 
     In a preferred embodiment, the lower segmented ring comprises three separate segments arranged in a circumferential array with gaps therebetween. Further, flexible links may join the three separate segments of the lower segmented ring. The connection members may comprise elongate strips with ratcheting teeth, and the apertures in the securing ring include ratchet pawls that engage the ratchet teeth on the connection members. Alternatively, the connection members comprise sutures, and the mating apertures in the securing ring comprise suture clamps. Preferably, the securing ring has an undulating contour with three axially elevated peaks intermediate three axial valleys, and wherein the lower segmented ring generally mimics the undulating contour of the securing ring and has three segments that correspond to the three axially valleys of the securing ring, and wherein there are at least two connection members extending upward from each segment of the lower segmented ring. 
     In accordance with another preferred embodiment, a knotless aortic heart valve prosthesis comprises a prosthetic heart valve having a securing ring extending outward from an inflow end thereof. The securing ring has an undulating contour with three outwardly projecting lobes intermediate three radially inward relief areas, the relief areas defining axial peaks and the lobes defining axial valleys, and the securing ring having apertures therethrough. A lower segmented ring smaller in circumference than the securing ring and having an undulating shape mimics the shape of the securing ring. Finally, a plurality of elongated flexible connection members extend upward from the segmented ring through the apertures formed in the securing ring so as to couple the two rings together and clamp a valve annulus therebetween, thereby securing the heart valve to the valve annulus without sutures. The prosthesis may further have a plurality of protruding members that extend generally radially outward from the lower segmented ring that help anchor the heart valve to the valve annulus. Desirably, the lower segmented ring includes rows of teeth on an upper surface thereof that help anchor the heart valve to the valve annulus. 
     In another preferred embodiment, the lower segmented ring comprises three separate segments arranged in a circumferential array with gaps therebetween. Further, flexible links may join the three separate segments of the lower segmented ring. The connection members may comprise elongate strips with ratcheting teeth, and the apertures in the securing ring include ratchet pawls that engage the ratchet teeth on the connection members. Alternatively, the connection members comprise sutures, and the mating apertures in the securing ring comprise suture clamps. 
     A method for implanting an aortic heart valve prosthesis comprises the steps of
         a. inserting a segmented lower ring downward through an aortic annulus from the atrial to ventricular side, the lower ring having three segments that may be arranged together below the aortic annulus in a non-circular ring shape, each segment having at least one connection member secure thereto and projecting upward through the aortic annulus to the atrial side thereof;   b. advancing a heart valve and securing ring toward the aortic annulus, the securing ring extending outward from an inflow end of the heart valve and having apertures therethrough;   c. inserting each of the connection members extending upward from the lower ring through an aperture in the securing ring around the heart valve;   d. advancing the heart valve and securing ring into contact with the aortic annulus;   e. applying tension to the connection members so as to clamp the aortic annulus between the lower ring and the securing ring;   f. securing the position of each connection member within its respective aperture; and   g. trimming each connection member closely above its respective aperture.       

     Preferably, the three segments of the lower ring are joined by flexible links. Additionally, the securing ring may have an undulating contour with axial peaks intermediate axial valleys, and a non-circular periphery with outwardly projecting lobes coinciding with the axial valleys and radially inward relief areas coinciding with the axial peaks. Furthermore, the three segments of the segmented lower ring preferably coincide with the outwardly projecting lobes of the securing ring, and have gaps therebetween coinciding with the radially inward relief areas of the securing ring. The connection members may comprise elongate strips with ratcheting teeth, and the apertures in the securing ring include ratchet pawls that engage the ratchet teeth on the connection members, and wherein the step of securing the position of each connection member within its respective aperture occurs by applying tension to the connection member. 
     In another embodiment, the invention is an implantable prosthesis anchor comprising: an upper support section; a lower support section; and at least one tension member; wherein the tension member is configured to apply forces to the upper support section and the lower support section such that the upper support section engages one surface of a heart annulus while the lower support section engages an opposing surface of the heart annulus. 
     In one instance, the tension member is a length of suture material that passes through the upper support section and the lower support section in an alternating fashion forming a zigzag pattern around the periphery of the implantable prosthesis anchor. In another instance, each tension member comprises a strip with ratchet teeth, the upper support section further comprises at least one tension member receiver, each tension member receiver comprises a pawl, and wherein the upper support section is configured to ratchet towards the lower support section by way of the pawl on each tension member receiver engaging the ratchet teeth of each tension member. In yet another instance, no tension member passes through native tissue. In yet another instance, the upper support section further comprises barbs adapted to contact annulus tissue that aid in clamping a portion of the heart annulus and the lower support section further comprises barbs adapted to contact annulus tissue that aid in clamping a portion of the heart annulus. 
     In one instance, the upper support section and the lower support section are made of a flexible material to allow either the upper support section or the lower support section to be elastically deformed and passed through the annulus of the heart. In another instance, the upper support section and the lower support section are collapsible down to a size suitable for trans-catheter delivery. In yet another instance, the upper support section and the lower support section are of a scalloped shape to better fit in a heart valve annulus. In yet another instance, the invention can further comprise a prosthetic heart valve attached to the upper support section. In yet another instance, the invention can further comprise a tubular cloth portion comprising a first end and a second end, wherein the cloth portion is attached at the first end to the upper support section and attached at a second end to the lower support section. 
     In another embodiment, the invention can be an implantable prosthesis anchor comprising: a lower support section with a plurality of engaging hooks extending off of an upper portion of the lower support section; an upper support section with a plurality of receiving holes; and a length of suture material passed through native tissue at least once and passed through the lower support section at least once; wherein the engaging hooks of the lower support section are configured to mate into the receiving holes of the lower support section and the length of suture material is configured to become clamped to the anchor when the upper support section is mated to the lower support section. 
     In one instance, the upper support section and the lower support section are collapsible down to a size suitable for trans-catheter delivery. In another instance, the invention can further comprise a plurality of locking members disposed within the prosthesis anchor to aid in clamping the length of suture material. In yet another instance, the locking members consist of pairs of flexible tubular members located in the suture holes that are configured to clamp the suture material when the upper support section mates into the lower support section. In yet another instance, the locking members consist of hinged flaps located in the suture holes that are configured to clamp the suture material when the upper support section mates into the lower support section. In yet another instance, the upper support section and the lower support section are configured to form an annuloplasty ring when mated together. 
     In yet another embodiment, the invention can be a method for implanting a prosthesis comprising the steps of: providing a prosthesis anchor comprising an upper support section, a lower support section, and a tension member; deploying the upper support section in the heart of a human patient; deploying the lower support section adjacent to the upper support section; applying a force to the tension member to draw the upper support section and lower support section towards each other causing native tissue to become clamped between the upper support section and the lower support section; and securing the tension member to fix the prosthesis anchor in place within the heart. 
     In one instance, the tension members comprise strips with ratchet teeth. In another instance, the invention can further comprise the step of attaching the lower support section to native heart tissue with at least one length of suture material. In yet another instance, the invention can further comprise the step of securing a heart valve to the upper support section. 
     In accordance with a further aspect of the application, an implantable prosthesis anchor and heart valve combination comprises an annulus anchor having a resilient upper ring and a resilient lower ring, and an annular connection portion therebetween, the annular connection portion having a smaller diameter to match a target annulus. The anchor is deployable to the target annulus so that the upper and lower rings flank the target annulus and the connection portion spans the target annulus. A prosthetic heart valve has an annular mating portion along its outside surface that clips onto the upper and lower rings of the annulus anchor. The annular connection portion preferably comprises one or more sutures that thread through sleeves located at spaced apart locations on the upper and lower rings, wherein the one or more sutures may be tensioned to pull the upper and lower rings toward each other and clamp against the target annulus. In one embodiment, the annular connection portion comprises a cloth surface with no gaps that covers the target annulus. In another embodiment, the annular connection portion comprises one or more resilient spring members biased to pull the upper and lower rings toward each other and clamp against the target annulus. 
     A further aspect of the present application includes an implantable prosthesis anchor that has a first support ring with a plurality of protruding members extending off of a facing surface. A second support ring having a plurality of receptacles in a facing surface that is sized to receive the protruding members on the first support ring. The facing surfaces of the first and second support rings may be brought together so that the protruding members of the first support ring are received into the receptacles of the second support ring. A plurality of lengths of suture material pass through native tissue at least once and each pass through one of the receptacles of the second support section. When the first support section mates to the second support section the protruding members each clamp a length of suture against the receptacle. In one version, implantable prosthesis anchor includes a prosthetic heart valve attached to one of the first and second support rings. Alternatively, one of the first and second support rings comprises an annuloplasty ring. In alternate embodiments, the protruding members and receptacles each comprise a cleat-style suture clamp or a button-style suture clamp. 
     Another implantable prosthesis anchor disclosed herein includes a first support ring with a plurality of receptacles in a facing surface, and a second support ring with a plurality of receptacles in a facing surface, wherein the facing surfaces of the first and second support rings may be brought together so that corresponding receptacles align. The prosthesis anchor further has a plurality of clips protruding from the facing surface of one of the first and second support rings and a plurality of mating opening in the other of the first and second support rings, the clips and openings holding the first and second support rings together. Furthermore, a plurality of compressible members are sized to fit between the aligned receptacles in the first and second support rings, the corresponding receptacles having a mutual size so as to compress the compressible members. A plurality of lengths of suture material passed through native tissue at least once and each pass through a pair of corresponding receptacles, wherein the compressible members each clamp a length of suture when the first support section mates to the second support section and engages the mating clips and openings. The compressible members desirably comprise elements separate from either of the first and second support rings. For instance, the compressible members comprise springs, or flaps extending from one of the first and second support rings. 
     Another implantable prosthesis anchor and heart valve combination disclosed herein includes a first support ring with a plurality of protruding members extending off of a facing surface, and a second support ring with a plurality of protruding members extending off of a facing surface. A prosthetic heart valve connects to the second support ring, and a plurality of elongated ratchet members extend from the first support ring through mating apertures formed in the second support ring so as to couple the two rings together. 
     An exemplary method for implanting a prosthesis disclosed herein comprises the steps of:
         a. providing a prosthetic heart valve having a soft flange;   b. providing a plurality of elongated hook members distributed around the soft flange, the hook members each having a curved distal end with a sharp tip;   c. advancing the assembly of the heart valve and hook members into an implant position with the soft flange on the outflow side of a heart valve annulus and the curved distal ends on the inflow side;   d. pulling the hook members proximally through the soft flange so that the curved distal ends engage an underside of the annulus and the sharp tips pierce the annulus tissue to embed the hook members therein; and   e. securing the soft flange to the hook members.       

     Disclosed herein are devices and methods for quickly, easily, and conveniently affixing a heart valve repair prosthesis to tissue within or near the heart. The invention advantageously reduces or eliminates the need to manually tie suture knots, a procedure that often entails the difficult process of manipulating sutures in the tight space around the surgery site. The invention can provide these advantages in any procedure where surgical knots are needed, especially where access may be limited, such as for example, in a minimally invasive or transcatheter procedure. 
     Disclosed herein are devices and methods that limit the physical exposure and time required in surgical knot tying. The invention advantageously allows for enhanced securing to tissue with minimal surgical exposure, implantation time and improved reliability. This can reduce the cost of surgery and increase the efficient use of clinicians&#39; time. Additionally, the knotless embodiments of the present invention eliminate suture tails that can cause abrasion in the surrounding tissue. The present invention can lead to shortened hospital stays and a lower rate of repeat surgical interventions to correct complications. 
     A further understanding of the nature and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be explained and other advantages and features will appear with reference to the accompanying schematic drawings wherein: 
         FIG. 1  is a drawing of a prior art heart valve implanted in the aortic valve position of a human heart. 
         FIG. 2  is an enlarged view of the prior art heart valve of  FIG. 1 . 
         FIG. 3  is a drawing of an intermediate step of the implantation procedure of the prior art heart valve shown in  FIG. 1 . 
         FIG. 4  is a drawing of a dual-ring annulus anchoring device with a filamentary connection portion according to one embodiment of the present invention. 
         FIG. 5  is a drawing of an alternative dual-ring annulus anchoring device with a cloth connection portion according to another embodiment of the present invention. 
         FIG. 6  is a drawing of the anchoring device of  FIG. 4  implanted near an annulus of the human heart. 
         FIG. 7  is a drawing of a prosthetic heart valve installed over the anchoring device shown in  FIG. 4 . 
         FIG. 8  is a drawing of an alternative dual-ring annulus anchoring device according to one embodiment of the present invention. 
         FIG. 9  is a drawing of the anchoring device shown in  FIG. 8  implanted in an annulus of the human heart 
         FIG. 10  is a drawing of a dual-ring annulus anchoring device having cleat-style attachment clips according to another embodiment of the present invention. 
         FIG. 11  is a top view of the anchoring device of  FIG. 10 . 
         FIGS. 12A-B  are enlarged views of the attachment portion of the anchoring device of  FIG. 10 . 
         FIGS. 13A-B  are section views of an alternate button-style attachment portion of an anchoring device according to an alternative embodiment of the present invention. 
         FIGS. 14A-D  are multiple views of another alternative compressive attachment portion of an anchoring device according to an alternative embodiment of the present invention. 
         FIGS. 15A-D  are multiple views of yet another alternative compressive attachment portion of an anchoring device according to an alternative embodiment of the present invention. 
         FIGS. 16A-D  are multiple views of yet another alternative anchoring device according to an alternative embodiment of the present invention. 
         FIG. 17  is a drawing of an anchoring device according to another embodiment of the present invention having mating rings with teeth. 
         FIG. 18  is a drawing of the device in  FIG. 17  after implantation. 
         FIG. 19  is a drawing of an alternative device according to another embodiment of the present invention having mating rings with teeth and a ratchet connector. 
         FIGS. 20A-D  are multiple views of an annuloplasty device according to yet another embodiment of the present invention. 
         FIGS. 21 and 22  schematically show an alternative system for attaching a prosthetic heart valve to an annulus without the use of sutures using a series of hooks ulled through the valve to engage the annulus. 
         FIGS. 23-26  illustrate a further alternative knotless heart valve anchoring system that uses shaped flanges connected by cable ties. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Various embodiments of the present invention comprise heart valve repair or replacement prosthesis anchors that are well-suited for improving ease of implantation, reducing surgical exposure, and improving prosthesis attachment. It should be appreciated that the principles and aspects of the embodiments disclosed and discussed are also applicable to other devices having different structures and functionalities. For example, certain structures and methods disclosed may be applicable to other types of surgical procedures, namely annuloplasty ring implant for heart valve repair. Furthermore, certain embodiments may also be used in conjunction with other medical devices or other procedures not explicitly disclosed. However, the manner of adapting the embodiments described to various other devices and functionalities will become apparent to those of skill in the art in view of the description that follows. 
     A schematic drawing of a prior art prosthetic heart valve implanted in the heart  1  is shown in  FIG. 1 . The left atrium  2  and the left ventricle  3  are shown separated by the mitral valve  6 . The aortic valve  7  is at the outflow end of the left ventricle  3 . On the opposite side of the heart, the right atrium  5  and the right ventricle  4  are shown separated by the tricuspid valve  8 . The pulmonary valve  9  is at the outflow end of the right ventricle  4 . A prior art prosthetic heart valve  10  is shown implanted in the aortic valve  7  position. 
     An enlarged view of the aortic valve  7  is shown in  FIG. 2 . The aortic annulus  11 , a fibrous ring extending inward, can be seen with the prior art prosthetic heart valve  10  sutured in place above it. A step of the procedure to implant the prior art prosthetic heart valve  10  is shown in  FIG. 3 . During implantation, a clinician passes sutures  12  through the annulus  11  of the aortic valve  7 . While the heart valve is held on a fixture or holder  14 , a clinician can thread the suture  12  free ends through a sewing ring  13  on the prosthetic heart valve  10 . Thus, both free ends of each suture  12  extend out of adjacent portions of the sewing ring  13 . The valve  10  is then ‘parachuted’ down in the direction shown. The clinician moves the valve  10  down the array of sutures  12  and pulls the sutures  12  tight so that a seal is formed between the sewing ring  13  and the aortic annulus  11 . Next, the clinician ties each suture  12  free end to another free end securing the prosthetic heart valve  10  in place. Normally this process entails about 4-8 knots per suture and 12-20 sutures are used per implant. The ends of each suture  12  are clipped leaving a suture tail comprised of the suture used to create each knot. 
     Turning now to the present invention, certain efficiencies which reduce the procedure time will be explained. In the description that follows, the aortic annulus is used as the implantation site to illustrate the embodiments. The teachings of this invention can also be applied to the mitral, pulmonary, and tricuspid valves; or indeed, other valves in the body, including venous valves. Where possible, variations of each embodiment are discussed serially with common numbers used for common structure. Where structure is similar but design varies from device to device, each new instance of structure is given a prime symbol to denote its difference from a prior version. For, example  22 ,  22 ′, and  22 ″ refer to three different designs for a similar part of several embodiments. 
     An anchoring device  20  according to one embodiment of the present invention is shown in  FIG. 4 . The device comprises an upper ring  21 , a lower ring  22  and a resilient connection portion  23  that tends to bring the upper and lower rings together. In a preferred embodiment the upper ring  21  and lower ring  22  are made out of a flexible biocompatible metal such as stainless steel. The connection portion  23  can consist of a flexible elongate material such as one or more lengths of metal thread or wire. In a preferred embodiment, the connection portion  23  comprises suture material made of a synthetic polymeric fiber. In one embodiment, a single length of suture material of the connection portion  23  passes in and out of sleeves  24  located at spaced apart locations on the upper and lower rings. Alternatively, the connection portion  23  can comprise one or more stiff members such as rods to bring the upper and lower ring together and clamp onto tissue. In general, the connection portion  23  either acts like a plurality of tension springs that bias the upper and lower rings toward one another, or if it is a length of suture material it can be cinched to pull the rings together. 
     An alternative device according to one embodiment of the present invention is shown in  FIG. 5 . The device  20 ′ is similar to the device  20  in that it has an upper ring  21  and a lower ring  22 . But the alternative device has a connection portion  23 ′ that is comprised of a section of cloth. The cloth preferably is a synthetic biocompatible type cloth such as polytetrafluoroethylene (e.g. Teflon PTFE) or polyester (e.g. Dacron), although other synthetic or natural cloths may be used. 
     Turning back to the anchor  20  shown in  FIG. 4 , preferably the anchor  20  is flexible such that it can be deformed and passed through an annulus of a heart valve. This can be accomplished by a clinician in a traditional open heart surgery or via tools used in a minimally invasive or transcatheter procedure. The anchor  20  is shown in a deployed state in  FIG. 6 . The resilient upper ring  21  is located above the annulus  11 , while the resilient lower ring  22  is located below the annulus  11 . The anchor  20  is deployable to the target annulus so that the upper and lower rings  21 ,  22  expand to flank the target annulus and the connection portion  23  which has a smaller diameter spans the target annulus. The connection portion  23  pulls the upper ring  21  towards the lower ring  22 . In a preferred embodiment, the connection portion  23  is a length of suture material that can be tensioned by pulling on a free exposed end. This allows a clinician to tighten the anchor  20  onto the annulus  11  and clamp tissue in between the upper ring  21  and the lower ring  22 . In addition, the open areas between the suture material in the connection portion  23  will allow tissue to protrude through and become trapped in between. The protruding tissue aids in securing the device and promotes tissue ingrowth. The suture can be secured by crimping the sleeve  24  adjacent the free end of the suture. Alternatively, the suture free end may be tied to another free end or to another location on the anchor  20 . 
     With respect to the alternative device in  FIG. 5 , the connection portion  23 ′ is comprised of a section of cloth and thus does not bias the rings  21 ,  22  together. However, the diameter of the rings is greater than that of the valve annulus and thus one of the two rings can be compressed to pass through the annulus whereupon the two rings expand outward on either side to flank the annulus (as in  FIG. 6 ). The cloth connection portion  23 ′ circumscribes and covers the native annulus, thus evening out irregularities and containing loose pieces of calcification and the like. 
     A heart valve  26  is shown deployed over the anchor  20  in  FIG. 7 . The heart valve  26  has an annular mating portion  27  along its outside surface that clips onto the upper and lower rings  21  and  22  of the anchor  20 . The mating portion  27  of the heart valve also applies pressure to the annulus  11  to ensure a robust and leak free fit. 
     An alternative anchor  20 ″ is shown in  FIG. 8 . This device is similar to the anchor  20  shown in  FIG. 4  except that the upper ring  21 ″ and lower ring  22 ″ are flat rings with a plurality of holes. Preferably, one or both of the rings  21 ″,  22 ″ are made of a flexible polymeric material so that a clinician may bend one of the rings and pass it through the native annulus during implantation. Alternatively, the upper ring  21 ″ and lower ring  22 ″ may be made of a rigid material, and the anchor can be tilted and passed through the annulus sideways, using the natural elasticity of the annulus to accommodate insertion. A suture,  23  loops through the holes in ring in an alternating fashion to join the upper ring  21 ″ and lower ring  22 ″. The anchor  20 ″ is shown in an implanted state in  FIG. 9 . The design of the anchor  20 ″ allows it to be clamped onto the annulus like the device  20  in  FIG. 4 . A clinician can pull on a free end of the suture  23  to draw the upper ring  21 ″ toward the lower ring  22 ″. The suture can then be secured with a single knot to fix the anchor in place. 
     A device according to an alternative embodiment of the present invention is shown in  FIG. 10 . This device is a two-part anchor for a heart valve repair prosthesis. The bottom portion comprises a sewing ring  30  and the top portion comprises a locking ring  29 . Preferably, the sewing ring  30  and the locking ring  29  are made of a semi-rigid polymeric material. A heart valve  31  may be attached to the locking ring  29  as shown in  FIG. 10 . Alternatively, the device may be used as an annuloplasty ring without a heart valve attached to the locking ring  29 . The sewing ring  30  comprises cleat-style clips  32  that mate into holes  33  on the locking ring  29 .  FIG. 11  shows a top view of the locking ring  29  and holes  33 . 
     A close-up view of the clips  32  on the sewing ring  30  in an unlocked state is shown in  FIG. 12A . To implant the anchor, a clinician places at least one suture  34 , and typically an array of sutures, through the tissue of the annulus  11 . A clinician can place the free ends of each suture through the hole between the clips  32  on the sewing ring  30 . Preferably, the two free ends of each suture will be placed through adjacent clips  32  on the sewing ring  30 . Once all sutures  34  have been placed, the clinician presses the locking ring  29  down on the sewing ring  30  transforming the device into a locked state as shown in  FIG. 12B . The holes  33  in the locking ring  29  are tapered to force each of the two arms of the clips  32  on the sewing ring  30  towards each other to secure the suture  34  in between. This prevents each suture  34  from backing out and secures the device to the annulus  11 . Also, the inner facing surfaces of each clip  32  finger are desirably roughened, grooved, have teeth or otherwise have a characteristic that enhances their grip onto the sutures. The illustrated embodiment acts like a cam cleat on a sailboat which tightens on the line in tension. 
     An alternative button-style suture fastening design is show in  FIGS. 13A-B . In this design, the sewing ring  30 ′ has holes  33 ′ that mate with buttons or tabs  32 ′ on the locking ring  29 ′. The device is shown in an unlocked state in  FIG. 13A . Each suture  34  free end that has been pre-installed at the annulus passes through a hole  33 ′ on the sewing ring  30 ′ and then through a hole in the locking ring  29 ′ that is near an associated tab  32 ′. When a clinician pushes the locking ring  29 ′ down onto the sewing ring  30 ′ the device transforms to a locked state as shown in  FIG. 13B . In the locked state, the suture  34  free end is secured between the side of the tab  32 ′ and the hole  33 ′. This prevents each suture  34  from backing out and secures the device to the annulus  11 . 
     Another alternative suture fastening design is shown in  FIGS. 14A-D . A device according to this design further comprises compressible suture gripping elements  35  disposed within a cavity created by holes in the locking ring  29 ″ and the sewing ring  30 ″. Preferably, the suture gripping elements are a pair of flexible generally tubular elastomeric (e.g., silicone) members. The device is shown in an unlocked state in  FIGS. 14A-B . Each suture  34  free end that has been pre-installed at the annulus passes between the suture gripping elements  35 . When a clinician pushes the locking ring  29 ″ down on the sewing ring  30 ″ the device transforms into a locked state as shown in  FIGS. 14C-D , with a plurality of clips (not numbered) protruding from the facing surface of the sewing ring  30 ″ extending into mating openings in the locking ring  29 ″ to hold the two rings together. The tapered walls of the cavity formed between the locking ring  29 ″ and the sewing ring  30 ″ force the suture gripping elements  35  towards each other gripping each suture  34  free end. This prevents each suture  34  from backing out and secures the device to the annulus  11 . 
     Yet another alternative device fastening design is shown in  FIGS. 15A-D . A device according to this design further comprises resilient hinged flaps  36  attached to the locking ring  29 ″′ and extending down through holes in the sewing ring  30 ″′. Preferably, the hinged flaps  36  are made from a flexible polymeric material. The device is shown in an unlocked state in  FIGS. 15A-B . Each suture  34  free end that has been pre-installed at the annulus passes between the hinged flaps  36 . When a clinician pushes the locking ring  29 ″′ down on the sewing ring  30 ″′ the hinged flaps  36  are compressed inward to retain the sutures  34  and transform the device into a locked state as shown in  FIGS. 15C-D . Again, clips and mating openings (not numbered) hold the two rings together. The walls of each hole in the sewing ring  30 ′″ force the hinged flaps  36  towards each other and grip the each suture  34  free end. This prevents each suture  34  from backing out and secures the device to the annulus  11 . 
     Yet another alternative suture fastening design is shown in  FIGS. 16A-D . A device according to this design further comprises spring clips  37  disposed within a cavity created by a hole in the locking ring  29 ″″. Preferably, spring clips  37  are made of a flexible metal material such as stainless steel. The device is shown in an unlocked state in  FIGS. 16A-B . Each spring clip  37  is wedged into a hole in the locking ring  29 ″″ in a bent position so that a clinician can pass a suture free end that has been pre-installed at the annulus between the two bottom portions of the spring clip and out through a hole in the top of each spring clip  37 . When the locking ring  29 ″″ is pushed down on the sewing ring  30 ″″, the device transforms into a locked state as shown in  FIGS. 16C-D . In the locked state, each spring clip  37  snaps into a straightened position such that the two bottom portions of the spring clip  37  meet and are forced against each other. Each suture  34  free end is clamped between the two bottom portions of the spring clip  29 ″″. This prevents each suture  34  from backing out and secures the device to the annulus  11 . 
     A device according to yet another embodiment is shown in  FIG. 17 . This device comprises an upper ring  38 , a lower ring  39  and connection members  42 . In a preferred embodiment, the upper and lower rings are made of a flexible material such as stainless steel. Preferably, the rings are generally circular and have a generally flat bottom profile when viewed from the side. There are teeth  41  on the upper ring  38  and lower ring  39 . A prosthetic heart valve  31  is shown attached to the upper ring  38 . In a preferred embodiment, the connection members  42  are lengths of suture material made of a synthetic polymeric fiber. 
     To implant the device, a clinician can deform one of the rings and pass it through the annulus of a heart valve. Alternatively, the upper ring  38  or lower ring  39  may be made of a rigid material, and the anchor can be tilted and passed through the annulus sideways, using the natural elasticity of the annulus to facilitate implantation. After this step, the upper ring  38  is on one side of the annulus and the lower ring  39  is on the other side of the annulus. A clinician can pull the connection members  42  to draw the upper ring  38  and the lower ring  39  towards each other to clamp the annulus  11  in between as shown in  FIG. 18 . Once in place, the connection members  42  can be crimped, snapped, tied, or locked to anchor the device. The teeth  41  help to secure the device in place and prevent leakage around the valve or migration of the valve. Although the teeth  41  are shown axially oriented, they may also be angled slightly outward to more aggressively anchor into the annulus tissue. 
     A device similar to that shown in  FIG. 17  but with alternative connection members  42 ′ is shown in  FIG. 19 . The alternative connection members  42 ′ comprise elongate strips with ratcheting teeth. The connection members  42 ′ are attached to the bottom ring  39 ′. On the upper ring  38 ′ the connection members  42 ′ pass through receiver housings  48  with ratchet pawls that engage the ratchet teeth, much like cable ties. The ratcheting connection members  42 ′ allow the upper ring  38 ′ to be moved towards the lower ring  39 ′ to clamp on to a heart valve annulus and secure the device in place. The ratcheting connection members  42 ′, while allowing the upper and lower rings to be brought together, resist motion in the opposite direction. 
     Variations to the devices shown in  FIGS. 17 and 18  include using a different type of aggressive or semi-aggressive member or texture on the device to help secure it in place instead of the teeth  41  on the upper ring  38  and lower ring  39 . Other variations include using different types of connection members such as wires, or springs. Additionally, the upper and lower rings  38   39  may be made in a shape to better fit a native heart valve annulus. The aortic valve, for example, is made up of three curved sections along which each native leaflet attaches. Instead of being generally circular with a flat bottom profile, the rings could comprise a plurality of curved projections. The curved projections can extend outward from the center of the ring and downward from the bottom of the ring to form a scalloped shape. Thus, each curved projection on the upper and lower ring  38   39  would match up to a corresponding curved portion on a native aortic valve annulus. 
     A device according to yet another embodiment is shown in  FIG. 20 . This device is an annuloplasty ring for heart valve repair. The device can be implanted in a native heart valve annulus to reshape the annulus. It comprises an upper ring  43  and a lower ring  44  that snap together to form an annuloplasty ring. The device as shown is shaped to match the native mitral valve annulus, although other shapes may be used depending on the treatment site. The upper ring has a plurality of openings  46  through the body of the ring. Preferably, the openings  46  are slot shaped. The lower ring  44  has plurality of raised portions with grooved or toothed channels  47  that can be inserted into the openings  46  on the upper ring  43 . 
     The device is held in place by a plurality of sutures such as the suture  34  shown in  FIG. 20 . To implant the device, a clinician passes each suture  34  that has been pre-installed at the annulus through a grooved channel  47  on the lower ring  44 . The clinician may then pass the suture  34  through tissue near the implantation site and back out through the grooved channel  47 . The grooved channels  47  allow a clinician the flexibility in the placement of each suture  34 . Once each suture  34  has been placed, the top ring  43  can be snapped onto the bottom ring  44 . The slots in the top ring are sized such that when the top ring  43  is snapped onto the bottom ring  44  the grooved channels  47  are forced closed. Because the free ends of each suture are placed within a grooved channel  47 , the sutures are secured when the grooved channels  47  are forced closed. 
     With reference to  FIGS. 21 and 22 , a prosthetic heart valve  50  is shown being secured to a heart valve annulus  52 , such as an aortic annulus, without the use of sutures. The heart valve includes a stent structure having commissures  54  supporting flexible leaflets  56  that provide the occluding surfaces of the valve. A sewing ring or other such soft flange  58  surrounds an inflow end of the stent structure and is sized and shaped to conform to the annulus  52 . 
     A series of elongated hook members  60  passes through the soft flange  58  either through the flange material or through holes preformed therein. Each hook member  60  has a curved distal end  62  terminating in a sharp tip  64 . The curved distal ends  62  may be generally circular in curvature, J-shaped, U-shaped, and other shapes. In each embodiment, the sharp tip  64  projects back in the direction of the elongated body of the hook member  60  or may be angled slightly outwardly. In use, the hook members  60  are rotated to that the sharp tips  64  are oriented radially outward. The hook members  60  desirably bend slightly radially inward along their elongated bodies such that the curved distal ends  62  span a maximum diameter D that is smaller than the diameter of the annulus  52 , and smaller than the distance across the points at which the hook members  60  pass through the flange  58 . 
     To implant the heart valve  50 , the surgeon advances the assembly as seen in  FIG. 21  through a number of delivery approaches into the position shown, with the flange just on the outflow side of the annulus  52  and the curved distal ends  62  on the inflow side. The array of curved distal ends  62  circumscribes a circle smaller than the annulus, and thus can be easily inserted therethough from the outflow to inflow side. In any case the elongated hook members  60  are desirably not too rigid so that they may flex inward upon contact with the annulus  52  as they pass therethrough. 
     Subsequently, as seen in  FIG. 22 , the series of elongated hook members  60  are pulled proximally through the valve flange  58  so that the curved distal ends  62  engage the annulus. In the illustrated embodiment, the sharp tips  64  pierce the annulus tissue to embed the hook members  60  therein. A small clip  66  or other such device may be applied around each hook member  60  on the top side of the soft flange  58  to secure the hook members  60  in place, after which the tail end of the hook members are trimmed and removed. There should be at least three hook members  60  distributed evenly around the periphery of the valve  50 , and more preferably there are at least six; one for each commissure region and one intermediate each commissure region for aortic annuluses. The hook members may be made of a suitable polymer such as nylon, or a metal such as Nitinol or stainless steel. Pledgets (not shown) may also be pre-loaded on the curved distal ends  62  to help prevent the hook members from pulling through the annulus tissue when under tensile load. 
       FIGS. 23-26  illustrate a further alternative knotless heart valve anchoring system  80  that operates similarly to the system shown in  FIG. 19 . The system includes a prosthetic heart valve  82  having a leaflet supporting structure  84  and a contoured securing ring  86  around the inflow end thereof in the place and configuration where a sewing ring is usually found. The securing ring  86  has a series of through apertures  88  distributed around its periphery that receive elongated flexible connection members  90  therethrough. Each connection member  90  attaches at a distal end to a lower ring  92 , formed in the illustrated embodiment by three ring segments  94   a ,  94   b ,  94   c . The ring segments  94   a ,  94   b ,  94   c  may be separate or joined with flexible links, as indicated schematically in dashed lines in  FIG. 26A . The distal end of each connection member  90  preferably secures to the lower ring  92 , but may simply pass downward through apertures  96  therein and have a bead or other such enlargement (not shown) that prevents the connection member from pulling upward through the aperture. 
     In a preferred embodiment, the connection members  90  comprise elongate strips with ratcheting teeth. The apertures  88  on the securing ring  86  feature ratchet pawls (not shown) that engage the ratchet teeth on the connection members  90 , much like cable ties. The ratcheting connection members  90  allow the lower ring  92  to be gradually pulled closer to the securing ring  86  so as to clamp a heart valve annulus therebetween and secure the device in place, as seen in  FIG. 25 . Specifically, the “supra-annular” securing ring  86  contacts the outflow side of the annulus and the “infra-annular” lower ring  92  contacts the inflow side of the annulus. The ratcheting connection members  90  then resist separation of the rings  86 ,  92 . Alternatively, instead of engaging ratchet teeth, the connection members  90  may be simple sutures that are tied to the lower ring  92  and secured by clamps of some sort in the securing ring  86 . For instance, any of the clamping configurations described herein may be used. Further, the connection members  90  may be strip, wire, rod, filament, etc. 
     With reference in particular to  FIGS. 25-26 , beneficial details of the securing ring  86  and lower ring  92  are seen. The elevational view of  FIG. 25  shows the undulating axial contour of the securing ring  86 . The ring  86  includes three peaks  100  alternating with three valleys  102 , and generally conforming to an aortic annulus root. This helps match the shape of the ring  86  to the root so as to better clamp to the annulus and also to help eliminate paravalvular leakage. The underside plan view of  FIG. 26A  shows the non-circular outer peripheral edge of the ring  86  featuring three outward lobe regions  106  alternating with three relief areas  108 . The ring  86  thus has a rounded triangular peripheral shape. Again, this helps the ring  86  conform to the aortic root, with the lobe regions  106  projecting into and matching the coronary sinus lobes and the relief areas  108  providing relief for the inwardly-projecting valve commissure regions. The three valleys  102 , as seen in  FIG. 25 , correspond to the lobe regions  106 , while the three peaks  100  are centered in the relief areas  108 . 
     The lower ring  92  also generally mimics the undulating shape of the securing ring  86  so as to provide even clamping of the annulus therebetween. As seen in  FIG. 26A , the three ring segments  94   a ,  94   b ,  94   c  mostly span the outward lobe regions  106  of the securing ring  86  with breaks at the relief areas  108 , which register with the annulus commissures. This segmented assembly for the lower ring  92  serves several purposes. First, the breaks at the annulus commissures avoids clamping at those locations, which is the least flat or even surfaces around the annulus. Secondly, the three segments  94   a ,  94   b ,  94   c  may be inserted separately through the annulus from the outflow to the inflow side, or otherwise collapsed to reduce their aggregate profile, either way permitting the lower ring  92  to be formed on the inflow side of the annulus without difficulty. Finally, the individual segments  94   a ,  94   b ,  94   c  are relatively movable so that they may be separately pulled by the connecting members  90  to move both axially and radially relative to the securing ring  86 . 
     The lower ring  92  includes circumferentially-oriented ribs or teeth  110  on its upper surface. In the illustrated embodiment, each segment  94   a ,  94   b ,  94   c  has three rows of teeth  110  that angle slightly inwardly. These rows of teeth  110  help anchor the valve  82  to the annulus, as will be described below. Each segment  94   a ,  94   b ,  94   c  further has a plurality of outwardly-projecting fingers  112  that are rounded so as not to pierce tissue but nonetheless help anchor the structure. 
     In use, the surgeon advances the collapsed lower ring  92  (or each three segment  94   a ,  94   b ,  94   c  separately) through the aortic annulus from the outflow to the inflow side. Tail ends  114  of the connection members  90  extend up from the annulus and are threaded through the apertures  88  distributed around the securing ring  86  periphery. In a preferred embodiment, as seen in  FIG. 23  and also in dashed line in  FIG. 24 , the connection members  90  are more closely spaced at the lower ring  92  then at the securing ring  86  so as to form a conical array. In a preferred embodiment, there are at least one, and preferably two connection members  90  associated with each three lower segments  94 . Pulling on the tail ends  114  applies tension to the connection members to draw the two rings  86 ,  92  toward one another and clamp them around the annulus. As with earlier embodiments, the tail ends  114  are then trimmed off in a final step before closing the affected access passages and incisions. Since the lower ends of the connection members  90  are radially inward from the apertures  88  in the securing ring  86 , and due to the segmented nature of the ring  92 , pulling the connection members  90  displaces the three segments  94   a ,  94   b ,  94   c  both axially upward and radially outward. The rows of teeth  110  grab the annulus tissue and help cinch the assembly together. The outer rows of projecting fingers  112  frictionally engage the surrounding anatomy on the underside of the annulus and help retain the assembly from rotation about the flow axis. 
     The “supra-annular” securing ring  86  and the “infra-annular” lower ring  92  may be molded of a suitable polymer, such as nylon or Delrin. Alternatively, they may be machined from a suitable metal such as stainless steel. One or both may also be surrounded with a fabric covering to help tissue ingrowth. 
     While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein, and it is to be understood that the words which have been used are words of description and not of limitation. Therefore, changes may be made within the appended claims without departing from the true scope of the invention.