Patent Publication Number: US-2023157822-A1

Title: Annuloplasty Device

Description:
FIELD OF THE INVENTION 
     This invention pertains in general to the field of cardiac valve repair. More particularly the invention relates to an annuloplasty device or implant, such as an annuloplasty ring or helix, for positioning at the heart valve annulus and a method of repairing a defective heart valve. 
     BACKGROUND OF THE INVENTION 
     Diseased mitral and tricuspid valves frequently need replacement or repair. The mitral and tricuspid valve leaflets or supporting chordae may degenerate and weaken or the annulus may dilate leading to valve leak. Mitral and tricuspid valve replacement and repair are frequently performed with aid of an annuloplasty ring, used to reduce the diameter of the annulus, or modify the geometry of the annulus in any other way, or aid as a generally supporting structure during the valve replacement or repair procedure. The annuloplasty ring is typically implanted around the annulus of the heart valve. 
     A problem with prior art annuloplasty implants is to achieve correct positioning at the heart valve and fixate the implant in the correct position. Suturing devices for annuloplasty implants have disadvantages that makes it difficult to suture in the correct position, thereby resulting insufficient suturing strength, and also in a very time-consuming procedure, which increases the risks for the patient. Furthermore, suturing devices are often not sufficiently compact for catheter based procedures. The use of clips for positioning annuloplasty implants is also associated with challenges, in particular when implanting helix rings that are to be positioned on either side of a heart valve. Insufficient fixation of such implant lead to traumatic effects since the fixation structure must ensure the correct position of the device over time. A further problem in the prior art is thus also to achieve a reliable fixation at the annulus of the heart valve. An annuloplasty implant is intended to function for years and years, so it is critical with long term stability in this regard. 
     The above problems may have dire consequences for the patient and the health care system. Patient risk is increased. 
     Hence, an improved annuloplasty implant would be advantageous and in particular allowing for avoiding more of the above mentioned problems and compromises, and in particular ensuring secure fixation of the annuloplasty implant, during the implantation phase, and for long-term functioning, in addition to a less complex procedure, and increased patient safety. A related method would also be advantageous. 
     SUMMARY OF THE INVENTION 
     Accordingly, examples of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing a device according to the appended patent claims. 
     According to a first aspect an annuloplasty device is provided comprising first and second support rings being configured to be arranged as a coil in a first configuration around an axial direction, wherein the first and second support rings are configured to be arranged on opposite sides of native heart valve leaflets of a heart valve, wherein the first and second support rings are separated with a first pitch distance in the axial direction, in the first configuration, wherein the first and second support rings are configured to assume a contracted state having a second pitch distance in the axial direction being shorter than the first pitch distance, and wherein the first and second support rings are configured to be transferable between the first configuration and the contracted state to pinch the heart valve leaflets. 
     According to a second aspect a method of repairing a defective heart valve is provided comprising positioning first and second support rings of an annuloplasty device in a first configuration as a coil on opposite sides of native heart valve leaflets of the heart valve, and activating a contracted state of the annuloplasty device so that a first pitch distance between the first and second support rings in the first configuration is reduced to a second pitch distance being shorter than the first pitch distance, whereby the first and second support rings move towards each other to pinch the native heart valve leaflets. 
     Further examples of the invention are defined in the dependent claims, wherein features for the second aspect are as for the first aspect mutatis mutandis. 
     Some examples of the disclosure provide for a facilitated positioning of an annuloplasty implant at a heart valve. 
     Some examples of the disclosure provide for a facilitated fixation of an annuloplasty implant at a heart valve. 
     Some examples of the disclosure provide for a less time-consuming fixation of an annuloplasty to a target site. 
     Some examples of the disclosure provide for securing long-term functioning and position of an annuloplasty implant. 
     Some examples of the disclosure provide for a reduced risk of damaging the anatomy of the heart such as the annulus or the valve leaflets. 
     Some examples of the disclosure provide for facilitated guidance of an annuloplasty implant to an annulus of a heart valve. 
     Some examples of the disclosure provide for a more secure implantation of an annuloplasty implant in narrow anatomies. 
     Some examples of the disclosure provide for avoiding interference of the annuloplasty implant with the chordae of the valve leaflets. 
     It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which 
         FIG.  1   a    is a schematic illustration of an annuloplasty implant or device with first and second support rings separated with a first pitch distance in an axial direction, in a first configuration, according to an example; 
         FIG.  1   b    is a schematic illustration of an annuloplasty device with first and second support rings separated with a second pitch distance in the axial direction, in a contracted state, according to an example; 
         FIG.  2   a    is a schematic illustration of an annuloplasty device positioned at a heart valve, in the first configuration, according to an example; 
         FIG.  2   b    is a schematic illustration of an annuloplasty device positioned at a heart valve, in the contracted state, according to an example; 
         FIG.  3    is a schematic illustration of an annuloplasty device, in a side view, according to an example; 
         FIG.  4    is a schematic illustration of an annuloplasty device, in a side view, according to an example; 
         FIGS.  5   a - b    are schematic illustrations of an annuloplasty device comprising an interior channel, in side views, according to an example; 
         FIGS.  5   c - f    are schematic illustrations of an annuloplasty device comprising an interior channel, in detailed side views, according to examples of the disclosure; 
         FIG.  6    is a schematic illustration of an annuloplasty device, in a side view, according to an example; 
         FIG.  7    is a schematic illustration of an annuloplasty device, in a side view, according to an example; 
         FIG.  8    is a schematic illustration of an annuloplasty device comprising an interior channel, in a side view, according to an example; 
         FIGS.  9   a - b    are schematic illustrations of an annuloplasty device, in side views, according to an example; 
         FIGS.  10   a - b    are schematic illustrations of an annuloplasty device, in cross-sectional views, according to an example; 
         FIG.  11   a    is a flow chart of a method of repairing a defective heart valve according to one example; and 
         FIG.  11   b    is another flow chart of a method of repairing a defective heart valve according to one example. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Specific embodiments of the invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements. 
     The following description focuses on an embodiment of the present invention applicable to cardiac valve implants such as annuloplasty rings. However, it will be appreciated that the invention is not limited to this application but may be applied to many other annuloplasty implants and cardiac valve implants including for example replacement valves, and other medical implantable devices. 
       FIGS.  1   a - b    are schematic illustrations of an annuloplasty device  100  or implant comprising first  101  and second  102  support rings being configured to be arranged as a coil in a first configuration around an axial direction  103 . The first and second support rings  101 ,  102 , are configured to be arranged on opposite sides of native heart valve leaflets  301  of a heart valve, as illustrated in  FIGS.  2   a - b   . As shown in  FIG.  2   a   , the first support ring  101  may be arranged on an atrial side of the heart valve, and the second support ring  102  may be arranged on a ventricular side. The first support ring  101  thus extends along the annulus of the heart valve. The first and second support rings  101 ,  102 , are connected to form a coil- or helix shaped ring. The coil extends through the valve opening (dashed line) at a commissure  302  thereof, as schematically illustrated in  FIG.  2   a   . The first and second support rings  101 ,  102 , are separated with a first pitch distance (p 1 ) in the axial direction  103 , in the first configuration, as illustrated in  FIGS.  1   a  and  2   a   . The first and second support rings  101 ,  102 , are configured to assume a contracted state having a second pitch distance (p 2 ) in the axial direction  103  being shorter than the first pitch distance (p 1 ), as illustrated in  FIGS.  1   b  and  2   b   . The pitch distance (p 1 , p 2 ) is the distance of the separation (i.e. gap) between the adjacent support rings  101 ,  102 , in the axial direction  103 . The first and second support rings  101 ,  102 , are configured to be transferable between the first configuration and the contracted state, thereby allowing for pinching the heart valve leaflets  302 . This provides for facilitating a secure positioning of the first and second support rings  101 ,  102 , at the opposite sides of the heart valve, since the first and second support rings  101 ,  102 , are compressed towards each other in the contracted state. At the same time, the support rings  101 ,  102 , may be readily positioned at the correct position at the opposite sides of the heart valve when in the first configuration, since the first pitch distance (p 1 ) can be chosen to have a sufficient separation for facilitating navigation to the opposite sides of the valve. Thus, having the first and second support rings  101 ,  102 , configured to be transferable between the first configuration and the contracted state to pinch the heart valve leaflets provides for minimizing the risk of dislocation from the annulus, while providing for an easier implantation procedure. The procedure may thus be performed in a shorter amount of time. Having the support rings  101 ,  102 , compressed in the contracted state also provides for enhancing cell growth in the vicinity of the support rings  101 ,  102 , and a quicker healing. The device  100  as described thus also improves the long-term outcome of the valve repair procedure. 
     As discussed further below, the device  100  may comprise a shape-memory material, so that the first and second rings  101 ,  102 , assumes the first configuration after having been ejected from a delivery catheter (not shown). While positioned in the delivery catheter the device  100  may be stretched in an elongated shape. Alternatively, the device  100  may be arranged in the coiled configuration when being delivered to the target site, in which case it may be implanted at the target site for example by incision between the ribs or by opening the chest. The present disclosure, and the associated advantages described for the various examples, applies to both such variants of the device  100 . 
     The annuloplasty device  100  may comprise fastening units  104 ,  104 ′,  114 , configured to interlock the first support ring  101  with the second support ring  102  so that the first and second support rings  101 ,  102 , are transferred from the first configuration to the contracted state.  FIG.  3    shows a schematic illustration of fastening units  104 ,  104 ′, that are configured to be interlocked for compressing the support rings  101 ,  102 , towards each other. In one example, as schematically shown in  FIG.  3   , the fastening units  104 ,  104 ′, comprise elongated extensions  104  arranged on the first support ring  101 , and recesses  104 ′ arranged on the second support ring  102 , or vice versa. The extensions  104  interlocks with the recesses  104 ′, so that the support rings  101 ,  102 , are transferred to the contracted state with reduced pitch distance (p 2 ). The fastening units  104 ,  104 ′, may be integrated with the first and/or second support rings  101 ,  102 . This may provide for a robust and secure fastening mechanism. The fastening units  104 ,  104 ′, may also be formed of the same material as the first and/or second support rings  101 ,  102 . 
     As schematically illustrated in  FIG.  4   , the fastening units may comprise coil-shaped units  114  configured to be rotated relative the first and second support rings  101 ,  102 , and to overlap the first and second support rings  101 ,  102 , so that the coil shaped units  114  push the second support ring  102  towards the first support ring  101  when the coil-shaped units  114  are rotated. 
     The coil-shaped units  114  are thus dimensioned so that the first and second support rings  101 ,  102 , are entangled within adjacent individual coils of the coil-shaped units  114 . As a coil-shaped unit  114  is screwed into position over the first support ring  101 , the most distal coil of the coil-shaped unit  114  will eventually catch the second support ring  102  and the first and second rings  101 ,  102 , will be pushed towards each other, thereby reducing the pitch distance (as schematically illustrated by arrows in  FIG.  4   ). Efficient compression of the first and second rings  101 ,  102 , may thus be achieved. 
     The annuloplasty device  100  may comprise a stiffening unit  105 , and at least part of the first and second support rings  101 ,  102 , may comprise an interior channel  106  configured to receive the stiffening unit  105 .  FIG.  5   a    is a schematic illustration of an interior channel  106  extending along the first and second support rings  101 ,  102 . In  FIG.  5   b   , the stiffening unit  105  has been inserted into the interior channel  106 . The stiffening unit  105  may thus be arranged as an interior coil inside the interior channel  105 . The pitch distance of adjacent coils of the stiffening unit  105  may be varied to affect the pitch distance of the adjacent first and second support rings  101 ,  102 , along which the stiffening unit  105  extends. Hence, the stiffening unit  105  may exert a force onto the first and second support rings  101 ,  102 , to cause them to transfer to the compressed state (as schematically indicated by the opposed directed arrows in  FIG.  5   b   ). The stiffening unit  105  thus provides for a facilitated manipulation of the pitch distance (p 1 , p 2 ) between the first and second support rings  101 ,  102 . 
     In one example, insertion of the stiffening unit  105  into the interior channel  106  may cause the first and second support rings  101 ,  102 , to transfer from the first configuration to the contracted state. I.e. the stiffening unit  105  may have a relaxed heat set shape in which the distance between adjacent coils of the stiffening unit  105  may correspond to the second pitch distance (p 2 ). The first and second support rings  101 ,  102 , may have a relaxed heat set shape in which the distance between the adjacent first and second support rings  101 ,  102 , may correspond to the first pitch distance (p 1 ). The first and second support rings  101 ,  102 , may be flexible enough (i.e. more flexible than the stiffening unit  105 ) so that when the stiffening unit  105  is inserted into the interior channel  106 , the first and second support rings  101 ,  102 , are forced to also assume the second pitch distance (p 2 ), i.e. forced to the contracted state. 
     Insertion of the stiffening unit  105  into the interior channel  106  may increase the stiffness of the first and second support rings  101 ,  102 , due to the strength added by the stiffening unit  105  when arranged in the interior channel  106 . I.e. as the stiffness is increased, the force required to force the first and second support rings  101 ,  102 , a certain distance apart may be increased. The retention force provided by the first and second rings  101 ,  102 , against the valve tissue may thus be increased, providing a stronger pinch on the valve tissue positioned between the first and second support rings  101 ,  102 . A more secure fixation may thus be provided. It is also conceivable that in one example the insertion of the stiffening unit  105  increases the stiffness of the first and second support rings  101 ,  102 , without significantly affecting the distance between the first and second support rings  101 ,  102 , i.e. the pitch distance. The increased retention force, as mentioned above, may still provide for sufficient fixation of the device  100  at the annulus. The stiffness may be variably changed by positioning the stiffening unit  105  along various portions of the interior channel  106 . In further examples the stiffening unit  105  may be arranged in only the first support ring  101 , or only in the second support ring  102 , or only in part of the first support ring  101 , or in part of the second support ring  102 , or only in a first part of the first support ring and in a second part of the second support ring  102 . 
     In one example, the stiffening unit  105  may comprise a shape-memory material. Activation of the shape-memory material may cause the first and second support rings  101 ,  102 , to transfer from the first configuration to the contracted state. The stiffening unit  105  may thus be actively manipulated, once in place inside the interior channel  106 , so that its pitch distance is varied and thereby affecting the pitch distance (p 1 , p 2 ) of the first and second support rings  101 ,  102 , as described above. The shape-memory material may be configured to be activated in response to an activation temperature. Hence, the temperature of the stiffening unit  105  may be changed to affect the discussed shape-change thereof. 
     The annuloplasty device  100  may comprise at least a first stiffening unit  105  and a second stiffening unit  105 ′. The first and second stiffening units  105 ,  105 ′, may be configured to be arranged in the interior channel  106  simultaneously. This is exemplified in  FIGS.  5   c - d   , where a first stiffening unit  105  is introduced in the interior channel  106  ( FIG.  5   c   ), and a second stiffening unit  105 ′ is introduced in the interior channel  106  ( FIG.  5   d   ).  FIGS.  5   c - d    show only a second of the first and/or second support ring  101 ,  102 , but it should be understood that the first and second stiffening units  105 ,  105 ′, may be introduced along any portion of the first and second support rings  101 ,  102 , as explained above. The first and second stiffening units  105 ,  105 ′, may be introduced in sequence or simultaneously. Although the example only shows two stiffening units  105 ,  105 ′, it should be understood that any plurality of stiffening units may be introduced in the interior channel  106 . This provides for a gradual and variable adjustment of the stiffness of the first and/or second support rings  101 ,  102 , and/or a gradual and variable adjustment of the distance between the first and/or second support rings  101 ,  102 , i.e. the pitch distance (p 1 , p 2 ), as mentioned above. The retention of the first and second support rings  101 ,  102 , may thus be carefully optimized during different steps of the fixation procedure, and/or optimized for different types of anatomies without having to try different variations of the device  100 . The mechanical properties of the device  100  may instead be optimized in-situ, e.g. by simultaneously observing the flow dynamics of the modified heart valve. 
     The interior channel may comprise a first sub-lumen  106  and a second sub-lumen  106 ′, as exemplified in  FIGS.  5   e - f   . The first stiffening unit  105  may be configured to be arranged in the first sub-lumen  106  ( FIG.  5   e   ) and the second stiffening unit  105 ′ may be configured to be arranged in the second sub-lumen  106 ′ ( FIG.  5   f   ). The first and second stiffening units  105 ,  105 ′, may be introduced in sequence or simultaneously. This provides for an advantageous optimization as mentioned above. Additionally, having dedicated sub-lumens  106 ,  106 ′, for the first and second stiffening units  105 ,  105 ′, may provide for a facilitated insertion of the first and second stiffening units  105 ,  105 ′. Although the example shows two sub-lumens  106 ,  106 ′, it should be understood that any plurality of sub-lumens may be arranged in the first and/or second support ring  101 ,  102 , in which respective stiffening units  105 ,  105 ′, may be introduced, for optimization to different applications. 
     The first stiffening unit  105  may have a different stiffness than the second stiffening unit  105 ′. This may provide for a facilitated variation of the stiffness of the first and/or second support rings  101 ,  102 . In one example the first stiffening unit  105  may increase the stiffness gently and/or reduce the pitch distance with a first distance to first accurately position the device  100 , while introducing the second stiffening unit  105 ′, which may have a increased stiffness compared to the first stiffening unit  105 , provides for significantly increasing the stiffness of the first and/or second support rings  101 ,  102 , and/or reducing the pitch distance with a greater distance, compared to the first distance, to finally fixate the device  100  in place. A more secure and optimized fixation of the device  100  may thus be provided. 
     The first and second support rings  101 ,  102 , may comprise a magnetizing portion  107  comprising a material configured to be magnetized, or a magnetic material, so that the first and second support rings  101 ,  102 , transfer from the first configuration to the contracted state by a magnetic force from the magnetizing portion  107  acting the first and second support rings  101 ,  102 . Thus, the magnetizing portion  107  may comprising a material configured to be magnetized, e.g. by applying energy such as electromagnetic energy to the magnetizing portion  107 , to affect the degree of magnetization of the magnetizing portion  107 . For example, the magnetizing portion  107  may be arranged in contact with at least part of the first and second support rings  101 ,  102 , without being magnetized, so that that first and second support rings  101 ,  102  assume the first configuration. Then, energy may be applied to magnetize the magnetizing portion  107 , so that it causes a magnetic attraction force to act upon the first and second support rings  101 ,  102  (as schematically illustrated with arrows in  FIG.  6   ), for transferring to the contracted state. A section of the magnetizing portion  107  arranged in contact with the first support ring  101  may assume a different magnetic polarity compared to a section of the magnetizing portion  107  arranged in the second support ring  102 , so that an attraction force therebetween is produced. The first and second support rings  101 ,  102 , may be formed at least partly from a material comprising the magnetizing portion  107 . Alternatively, or in addition, the first and second support rings  101 ,  102 , may be configured to receive a magnetizing element  108 ,  108 ′,  113 , as described further below. Having a magnetizing portion  107  provides for facilitating transferring of the first and second support rings  101 ,  102 , to the contracted state for secure fixation to the heart valve. 
     The annuloplasty device  100  may comprise a magnetizing element  108 ,  108 ′,  113 , comprising a material configured to be magnetized and/or a magnetic material. I.e. the magnetizing element  108 ,  108 ′,  113 , may be magnetized at a desired point in time, e.g. when having been arranged in contact with at least part of the first and second support rings  101 ,  102 , by application of energy such as electromagnetic energy. The magnetizing element  108  may also comprise a magnetic material, that has already been magnetically polarized before being arranged in contact with the first and second support rings  101 ,  102 . At least part of the first and second support rings  101 ,  102 , may thus comprise a receiving portion  109  configured to receive and fixate the magnetizing element  108 ,  108 ′,  113 . Thus, when the magnetizing element  108 ,  108 ′,  113 , is arranged at the receiving portion  109 , the first and second support rings  101 ,  102 , are configured to transfer from the first configuration to the contracted state by a magnetic force from the magnetizing element  108 ,  108 ′,  113 , acting the first and second support rings  101 ,  102 . As explained, the magnetic force may be manifested either by applying energy to activate the polarization of the magnetizing element  108 ,  108 ′,  113 , or by arranging an already polarized magnetic element  108 ,  108 ′,  113 , at the receiving portion  109 . 
       FIGS.  7  and  8    are schematic examples of magnetic elements  108 ,  108 ′,  113 , arranged at such receiving portion  109 . In  FIG.  7   , a magnetic element  108 ,  108 ′, is arranged at two sections of the first and second support rings  101 ,  102 , with opposed magnetic polarities, so that when a magnetic field is present, an attractive magnetic force push the first and second rings  101 ,  102 , towards each other to the contracted state. 
       FIG.  8    is a schematic illustration where the receiving portion  109  may comprise an interior channel  106  arranged in the first and second support rings  101 ,  102 . The interior channel  106  may be configured to receive the magnetizing element  113 , whereby, when the magnetizing element  113  is arranged in the interior channel  106 , the first and second support rings  101 ,  102 , are configured to transfer from the first configuration to the contracted state by a magnetic force from the magnetizing element  113  acting the first and second support rings  101 ,  102 . 
     The magnetizing element  108 ,  108 ′,  113 , may be configured to be removably connected to the first and second support rings  101 ,  102 . Thus, once the first and second support rings  101 ,  102 , have been compressed by the magnetic force, into the contracted state, it is possible to remove the magnetizing element  108 ,  108 ′,  113 , e.g. when the surrounding tissue has grown and healed sufficiently, which may be advantageous e.g. in case of MRI investigations of the heart. 
     The annuloplasty device  100  may comprise a biodegradable restraining unit  110 . At least part of the first and second support rings  101 ,  102 , may be configured to engage with the restraining unit  110  to maintain a separation at the first pitch distance (p 1 ). The first and second support rings  101 ,  102 , may be configured to assume the contracted state, with a separation of the first and second support rings  101 ,  102 , at the second pitch distance (p 2 ) upon biodegradation of the restraining unit  110 . Thus, the first and second support rings  101 ,  102 , may be configured to have a relaxed heat set shape corresponding to the contracted state, with the second pitch distance (p 2 ). The restraining unit  110  may in this case be configured to force the first and second support rings  101 ,  102 , apart to assume the first configuration with the first pitch distance (p 1 ), as schematically illustrated in  FIG.  9   a   . Once the restraining unit  110  has been degraded, partly or completely, as schematically illustrated in  FIG.  9   b   , the structural integrity thereof will not be sufficient to force the first and second support rings  101 ,  102 , apart and the contracted state will be assumed. An effective transfer between the first configuration and the contracted state may thus be provided. This provides also for facilitating the positioning of the device  100  at both sides of the valve, since the first pitch distance (p 1 ) provides for avoiding undesired friction with the tissue or entanglement with parts of the anatomy. Although the restraining unit  110  has been described as being biodegradable, it is conceivable that it may be removed or weakened by other mechanisms. 
     The restraining unit  110  may be configured to be attached to an exterior  111  of the first and second support rings  101 ,  102 , as schematically illustrated in  FIG.  10   a   . Alternatively, or in addition, the restraining unit may be configured to be arranged in an interior  112  of the first and second support rings  101 ,  102 , as schematically illustrated in  FIG.  10   b   . In both cases, the restraining unit  110  provides for the above discussed compression of the first and second support rings  101 ,  102 , once it has been degraded. 
     The first  101  and/or second support  102  may comprise a shape-memory material. In this case, activation of the shape-memory material causes the first and second support rings  101 ,  102 , to transfer from the first configuration to the contracted state with the reduced pitch distance (p 2 ). The shape-memory material may be configured to assume the contracted state in response to an activation temperature. It is conceivable that the device  100  may be kept at a defined temperature while arranged in a delivery catheter (not shown). Subsequently, when the device  100  is exposed to the warm tissue, when being ejected from the delivery catheter, the activation temperature may be reached, so that the first and second support rings  101 ,  102  are compressed towards each other. 
     The first  101  and/or second support  102  may comprise a shape memory material, such as NiTiNol, or another suitable biocompatible alloy that can be heat-set in defined shapes, in a heat treatment procedure. The shape-memory material may comprise a material having more than one phase, so that the shape of the support rings  101 ,  102 , may be actively varied as described above. The shape memory material can be conceived as any material that is able to change shape as desired, in response to outside interaction, for example with an energy source, such as providing heat and/or electromagnetic energy, that can be transferred to the device  100  to change its shape. It is also conceivable that the shape of the device  100  can be affected by direct mechanical manipulation of the curvature of the first  101  and/or second support  102 , e.g. by transferring a force or torque to the device  100  via a delivery device. Via the various mentioned shape-affecting procedures the device  100  may assume an elongated delivery configuration for advancement in a catheter, an initial shape when positioned in a coiled configuration along the annulus of the valve, i.e. the first configuration, and also an activated shape such as the contracted state described above for enhancing the strength of the fixation at an annulus of the heart valve. 
     The support rings  101 ,  102 , may be formed from a solid rod or other solid elongated structure, having various cross-sections, such as circular, elliptic, rhombic, triangular, rectangular etc. The support rings  101 ,  102 , may be formed from a hollow tube, or other hollow structures with the mentioned cross-sections. The support rings  101 ,  102 , may be formed from a sandwiched laminate material, comprising several layers of different materials, or different layers of the same material. The support rings  101 ,  102 , may be formed from a stent or a stent-like structure, and/or a braided material. The support rings  101 ,  102 , may be formed from a braid of different materials braided together, or from a braid of the same material. As mentioned, the support rings  101 ,  102 , may be formed from NiTinol, or another suitable bio-compatible material. The surfaces of the first and second support rings  101 ,  102 , may be provided with other materials and/or treated with different materials and/or structured to enhance resistance to breaking in case the material is repeatedly bent. 
     The first and second support rings  101 ,  102 , may have an elongated delivery configuration for advancement in a catheter, and an implanted shape in the above described contracted state. 
     A method  200  of repairing a defective heart valve is disclosed. The method  200  is schematically illustrated in  FIG.  11   a   , in conjunction with  FIGS.  2   a - b   . The order in which the steps are described should not be construed as limiting, and it is conceivable that the order of the steps may be varied depending on the particular procedure. The method  200  comprises positioning  201  first and second support rings  101 ,  102 , of an annuloplasty device  100  in a first configuration as a coil on opposite sides of native heart valve leaflets of the heart valve, and activating  202  a contracted state of the annuloplasty device so that a first pitch distance (p 1 ) between the first and second support rings  101 ,  102 , in the first configuration is reduced to a second pitch distance (p 2 ) being shorter than the first pitch distance (p 1 ), whereby the first and second support rings  101 ,  102 , move towards each other to pinch the native heart valve leaflets  301 . The method  200  thus provides for the advantageous benefits as described above in relation to the annuloplasty device  100  and  FIGS.  1 - 10   . A facilitated and more secure positioning of the device  100  at the heart valve is thus achieved. 
       FIG.  11   b    illustrates a further flow chart of a method  200  of repairing a defective heart valve. The order in which the steps of the method  200  are illustrated should not be construed as limiting and it is conceivable that the order in which the steps of the method  200  is carried out may be varied. The method  200  may comprise interlocking  203  the first support ring  101  with the second support ring  102  with fastening units  104 ,  104 ′,  114 , so that the first and second support rings  101 ,  102 , are transferred from the first configuration to the contracted state. 
     The fastening units may comprise coil-shaped units  114 . The method  200  may comprise rotating  204  the coil-shaped units  114  relative the first and second support rings  101 ,  102 , so that the coil shaped units  114  push the second support ring  102  towards the first support ring  101  upon rotating the coil-shaped units  114 . 
     The method  200  may comprise inserting  205  a stiffening unit  105  into an interior channel  106  arranged in at least part of the first and second support rings  101 ,  102 , to cause the first and second support rings  101 ,  102 , to transfer from the first configuration to the contracted state. 
     The stiffening unit  105  may comprise a shape-memory material. The method  200  may comprise activating  206  the shape-memory material to cause the first and second support rings  101 ,  102 , to transfer from the first configuration to the contracted state. 
     The method  200  may comprise inserting  2051  a first stiffening unit  105  into the interior channel  106 ,  106 ′, to increase the stiffness of the first and/or second support ring  101 ,  102 . The interior channel may be a single channel or comprise a plurality of sub-lumens  106 ,  106 ′, as exemplified in  FIGS.  5   c - f   . The method  200  may further comprise inserting  2052  a second stiffening unit  105 ′ into the interior channel  106 ,  106 ′, to further increase the stiffness of the first and/or second support ring  101 ,  102 , as described above in relation to  FIGS.  5   c - f   . The stiffness and the associated retention force between the first and second support rings  101 ,  102 , may thus be varied gradually by insertion of the first and second stiffening units  105 ,  105 ′. 
     The method  200  may comprise inserting  2051 ′ a first stiffening unit  105  into the interior channel  106 ,  106 ′, to reduce the pitch distance between the first and/or second support ring  101 ,  102 , e.g. with a first distance. The method  200  may further comprise inserting  2052 ′ a second stiffening unit  105 ′ into the interior channel  106 ,  106 ′, to further reduce the pitch distance between the first and/or second support ring  101 ,  102 , e.g. with a second distance. The distance between the first and second support rings  101 ,  102 , may thus be varied gradually by insertion of the first and second stiffening units  105 ,  105 ′, to vary the retention force between the first and second support rings  101 ,  102 . This provides for the advantageous benefits as further described above in relation to  FIGS.  5   c   - f.    
     The first and second support rings  101 ,  102 , may comprise a magnetizing portion  107  comprising a material configured to be magnetized or a magnetic material. The method  200  may comprise transferring  207  the first and second support rings  101 ,  102 , from the first configuration to the contracted state by applying  208  a magnetic force from the magnetizing portion  107  to act on the first and second support rings  101 ,  102 . 
     The method  200  may comprise inserting  209  a magnetizing element  113  into an interior channel  106  arranged in at least part of the first and second support rings  101 ,  102 , The method  200  may further comprise transferring  210  the first and second support rings  101 ,  102 , from the first configuration to the contracted state by applying  211  a magnetic force from the magnetizing element  113  to act on the first and second support rings  101 ,  102 . 
     The first and/or second support rings  101 ,  102 , may comprise a shape-memory material. The method  200  may comprise activating  212  the shape-memory material to cause the first and second supports rings  101 ,  102 , to transfer from the first configuration to the contracted state. 
     The method  200  may comprise activating  213  the shape-memory material in response to setting a temperature of the first and/or second support rings  101 ,  102 , to an activation temperature. 
     The present invention has been described above with reference to specific embodiments. However, other embodiments than the above described are equally possible within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used.