FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a device and method for correcting mitral valve insufficiency, and more particularly, to a device capable of restoring valve leaflet coaptation.

Mitral regurgitation (MR) - also referred to as mitral insufficiency or mitral incompetence - is a common disorder caused by insufficient closure (coaptation) of the mitral valve leaflets when the left ventricle contracts. This leads to abnormal leaking of blood backwards from the left ventricle, through the mitral valve and into the left atrium.

In the western world, MR is most commonly due to degenerative disease caused by morphological or functional changes to the leaflets, the valve annulus (which forms a ring around the valve leaflets), the papillary muscles and/or the chordae tendineae (which connect the valve leaflets to the papillary muscles). Morphological changes are classified under Degenerative Mitral Regurgitation (DMR) while functional changes are classified under functional mitral regurgitation (FMR).

Treatment of mitral valve regurgitation includes medication such as diuretics beta blockers, heart rhythm regulators and/or surgery for augmenting or replacing mitral valve function.

Mitral valve augmentation is typically effected via implantation of a ring-like device at the valve annulus. The procedure, termed annuloplasty, reshapes the mitral valve annulus to reestablish the physiological configuration and improve leaflet coaptation.

Mitral valve repair can be achieved by ring implantation alone, however, cases involving leaflets with sever anomalies and/or chordate elongation or damage to papillary muscles oftentimes require additional repair procedures.

One such procedure utilizes artificial chords which are sutured between the papillary muscles in the left ventricle (LV) and the free margin of the valve leaflet in order to recover the coaptation line. However, left ventricle remodeling in the postoperative period might negatively affect early results and lead to recurrence of mitral regurgitation. In addition to LV remodeling, suturing of artificial chord to the papillary muscle can be difficult to perform since the surgeon has limited access through the valve, making surgery more complex and time consuming and since it is oftentimes difficult to determine the correct length of artificial chords needed. In addition, the papillary muscle might be damaged by the procedure risking rupture of suturing site.

There is thus a need for, and it would be highly advantageous to have, a device for repairing mitral valve regurgitation devoid of the above limitations. SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided an annuloplasty device for mitral valve repair comprising a ring-like body having a posterior portion adapted to be implanted on a posterior aspect of the mitral valve annulus and an anterior portion connected to opposing legs being configured for crossing through opposing regions of a commissure of the valve when the posterior portion of the ring-like body is implanted on the posterior aspect of the mitral valve annulus, each of the opposing legs extends away from, and is angled medially and posteriorly with respect to, the ring-like body.

According to further features in preferred embodiments of the invention described below, a posterior angle of a first leg of the opposing legs is greater than the angle of a second leg.

According to still further features in the described preferred embodiments the anterior portion is open with each end transitioning to a leg of the opposing legs.

According to still further features in the described preferred embodiments distal ends of the opposing leg are interconnected via a bridge.

According to still further features in the described preferred embodiments the posterior angle of the first leg is 5-20 degrees greater than the angle of the second leg.

According to still further features in the described preferred embodiments each end of the anterior portion transitions to the leg through a series of inward, backward and downward bends.

According to still further features in the described preferred embodiments the device further comprising a cuff covering the ring.

According to still further features in the described preferred embodiments the device further comprises a cuff covering the bridge.

According to still further features in the described preferred embodiments the device further comprises a cuff covering at least a portion of the legs. According to still further features in the described preferred embodiments a first leg of the opposing legs crosses through a postero-medial commissure and a second leg crosses through an antero -lateral commissure.

According to still further features in the described preferred embodiments the posterior portion of the ring-like body is curved at a radius of 10-20 mm.

According to still further features in the described preferred embodiments the distance from the posterior end of the ring-like body to the commissures ranges between 3 to 9 mm.

According to still further features in the described preferred embodiments the inward bend has a radius of curvature of 0.5-1.5 mm.

According to still further features in the described preferred embodiments the cuff includes a first polymeric layer and a second fabric layer.

According to still further features in the described preferred embodiments the first polymeric layer is made of silicone.

According to still further features in the described preferred embodiments the cuff is fabricated from a polymer.

According to still further features in the described preferred embodiments the polymer is silicone.

According to still further features in the described preferred embodiments the polymer is covered with a fabric (e.g. polyester).

According to still further features in the described preferred embodiments the polymer is covered with a fabric (e.g. ePTFE).

According to still further features in the described preferred embodiments the ring-like body is fabricated from a wire having a diameter of 0.5-1.5 mm.

According to still further features in the described preferred embodiments the wire is composed of stainless steel, Nitinol or a Cobalt Chromium alloy.

According to still further features in the described preferred embodiments a distance between the bridge and the ring-like body is 5 -30 mm.

According to still further features in the described preferred embodiments each of the opposing legs is bent at a middle portion thereof.

According to still further features in the described preferred embodiments a length of each of the opposing legs is in a range of 15-40 mm. According to still further features in the described preferred embodiments the bridge length is proportional to the ring size, and can be 15-35 mm.

According to another aspect of the present invention there is provided an annuloplasty device for mitral valve repair comprising a ring-like body having a posterior portion adapted to be implanted on a posterior aspect of the mitral valve annulus and an anterior portion connected to opposing legs being configured for crossing through opposing regions of a commissure of the valve when the posterior portion of the ring-like body is implanted on the posterior aspect of the mitral valve annulus, wherein a length and a medial and posterior angle of the legs is selected so as to enable a bridge interconnecting the legs to reside within a rectangular volume defined by: 25 x 15 x 9 mm when the rectangular volume is positioned 5 mm below, with a 2-5 mm (preferably 5mm) posterior offset to, the ring-like body.

According to another aspect of the present invention there is provided a method of treating mitral valve insufficiency comprising: (a) providing an annuloplasty device having a posterior C-shaped portion and an anterior portion terminating with opposing legs interconnected via a bridge; and (b) anchoring the posterior C-shaped portion of the device on a posterior aspect of the mitral valve annulus such that the opposing legs cross through opposing regions of a commissure of the valve and extend away from, and angle medially and posteriorly with respect to, the posterior portion.

Once implanted, the ring-like body spans the antero-lateral and postero-medial trigons and then curved backwards to the commissars with the legs crossing at the commissures. The vertical distance from the curve end to the descending legs ranges between 3-8 mm.

According to still further features in the described preferred embodiments, the method further comprising (c) suturing said bridge to at least one leaflet of the mitral valve.

According to still further features in the described preferred embodiments, the method further comprising (c) attaching the bridge directly to the at least one leaflet of the mitral valve using a running suture.

According to still further features in the described preferred embodiments, the method further comprising (c) attaching the bridge to the at least one leaflet of the mitral valve using artificial chords. According to still further features in the described preferred embodiments, the method further comprising attaching said bridge to the inferior left ventricle wall using a trans-wall suture.

According to yet another aspect of the present invention there is provided an annuloplasty device for mitral valve repair comprising a ring-like body having a posterior portion adapted to be implanted on a posterior aspect of the mitral valve annulus and a pair of opposing legs being configured for crossing through opposing regions of a commissure of the valve when said posterior portion of said ring-like body is implanted on the posterior aspect of the mitral valve annulus, each of the opposing legs extending away from the ring-like body and angled medially and posteriorly with respect to, the ring-like body.

According to still further features in the described preferred embodiments, each of said opposing legs extends directly from said ring-like body.

The present invention successfully addresses the shortcomings of the presently known configurations by providing a mitral repair device that corrects short and long term insufficiencies in the annular, leaflet and sub valvular components of the mitral valve.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings:

FIG. 1 illustrates various portions of one embodiment of the present device.

FIGs. 2A-D are various views of the wire frame of one embodiment of the present device showing typical device geometry and dimensions.

FIGs. 3A-G are various views of one embodiment of the present device with the ring-like body and bridge covered with suturing cuffs.

FIG. 4 illustrates positioning of one embodiment of the present device with respect to the mitral valve annulus and chordae.

FIGs. 5A-C illustrate several engineering prototypes of one embodiment of the present device.

FIGs. 6A-C illustrate positioning of a virtual rectangular volume with respect to the ring-like body for defining a desired position of the bridge; dimensions and distances are in mm.

FIGs. 7A-B illustrates another embodiment of the present device in which the open eyelets angle up from the ring-like body.

FIG. 8 illustrates a prototype device with fabric suturing cuffs covering the ringlike body and bridge.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of a device which can be used to repair mitral valve insufficiency. Specifically, the present invention can be used to restore short and long term valve leaflet coaptation in cases of mitral regurgitation due to leaflet and/or chordate tendineae pathology and dysfunction and address problems arising from postoperative ventricle remodeling related to valve repair or continuous remodeling.

The principles and operation of the present invention may be better understood with reference to the drawings and accompanying descriptions. Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Mitral valve insufficiency can be effectively treated via implantation of annuloplasty rings which restore leaflet coaptation via annulus reshaping. However, ring implantation alone is oftentimes less effective in the long term since both leaflets and the sub-valvular apparatus can contribute to insufficiency (e.g., myxomatous leaflets chordate elongation/rupture, altered left ventricle spherity index). In addition, left ventricle geometry and volume might change in the post-operative period (i.e. the ventricle anatomy is restored to the non-pathological state or changes of the distance between the two papillary muscles) resulting in modification of the optimal chordae length leading to prolapse or tethering of the leaflets when the ventricle contracts.

The present inventors postulated that in order to minimize the negative effects of ventricular remodeling in the post-operative period, to facilitated chordate implantation and in the same time to guaranty correct length or to allow direct leaflet fixation. In particular, in patients with the myxomatos valves (Barlow disease), the posterior leaflet might be directly attached to the bridge, reducing the risk of SAM (systolic anterior motion, a known surgical risk in such patients).

In order to provide such function, the present inventor devised an annuloplasty device using the following guidelines:

(a) One or both leaflet and sub-valvular apparatus dysfunction are addressed in order to provide short and long term results;

(b) Anchoring the leaflet/s are directly or via artificial chords to a fixed ventricle-positioned structure which is a part of the device allowing accurate assessment of artificial chord length;

(c) artificial chords can be attached to device prior to implantation reducing ischemic time during the operation; the ease of repair and artificial chords implantation also notably reduces ischemia when the heart is not perfused; (d) device configuration minimizes interference with leaflets and chordae and minimizes contact with the LV wall;

(e) device configuration accommodates for any post-operative changes to the ventricle;

(f) amenable to minimally invasive surgery;

(g) papillary muscles are not always easily identified and accessed making artificial chordae implantation difficult; and

(h) implantation of artificial chordae directly to the papillary muscles might cause rapture and as a consequence severe mitral regurgitation.

As is illustrated in the Examples section herein below, the inventor discovered during experimentation with prototypes that for such a device to be effective must enable leaflet anchoring to the device directly or via artificial chords while minimizing or completely avoiding contact with the chordae tendineae and other heart structure (e.g., leaflets papillary muscle and myocardium).

Thus, according to one aspect of the present invention there is provided an annuloplasty device for mitral valve repair. The device includes a ring-like body (open or closed with complete or partial metal core) having a posterior portion adapted to be implanted on a posterior aspect of the mitral valve annulus and an anterior portion terminating with opposing legs configured for crossing through opposing regions of a commissure of the valve. The ends of the opposing legs interconnect via a bridge portion. Thus, when positioned at the mitral valve, the ring like body lies parallel to the annulus plane and the opposing legs are at an angle thereto with the bridge positioned in the left ventricle directly below the valve opening.

Referring now to the drawings, Figures 1-3G illustrate one embodiment of the present device which is referred to herein as device 10.

Figure 1 illustrates the general configuration and various portions of device 10. Device 10 includes a posterior portion 12 and an anterior portion 14 (shown separated by dashed line in Figure 1). Posterior portion 12 and the co-planar region of anterior portion 14 form a ring-like body 11.

Posterior portion 12 is a substantially C-shaped flat ring which is configured to be anchored to a posterior aspect of the mitral valve annulus. The radius of curvature of posterior portion 12 can be 10-20 mm. Anterior portion 14 is contiguous with posterior portion 12 and includes a series of inward and downward bends (20 and 22 respectively) to a pair of opposing legs 16; legs 16 are adjoined by a bridge 18 at distal ends thereof.

The radii of curvature of inward bend 20 and downward bend 22 are selected in order to enable legs 16 to cross through the postero-medial and antero-lateral commissure regions of the valve. These curvatures are also selected along with the length of legs 16 and bridge 18 in order to position legs 16 and bridge 18 in the ventricle away from chordae, while allowing suturing of artificial chords [e.g. Gore- Tex, polytetrafluoroethylene (ePTFE) or polypropylene] from bridge 18 to the valve leaflets. In the functional disease, the bridge 18 can be used to suspend the papillary muscle. Bend 20 has a radius of curvature of 0.5-2 mm, while bend 22 has a radius of curvature of 1-3 mm. Bend 20 also has the added function of forming an open eyelet 24. Legs 16, correlated to ring size, can be 15-40 mm long while bridge 18 can have a length of 15-35 mm. When device 10 is positioned at the mitral valve, bends 20 are situated at opposite trigones (left and right fibrous trigones), enabling anchoring of eyelets 24 to these fibrous regions.

Device 10 can be fabricated from stainless steel, cobalt chromium or Nitinol wire having a diameter of 0.5-1.5 mm. The device is fabricated by cold forming a wire over a machined mandrel and welding and/or crimping the ends of the wire to form bridge 18. The formed device is heat treated and electropolished. Bridge 18 can also be a polymeric or alloy tube glued over the bent end portions of legs 16.

Alternatively, device 10 can be fabricated by laser cutting a sheet or tube or by 3D printing a polymer or an alloy/metal.

The transition region between legs 16 and bridge 18 (indicated by 26 in Figure 1) can have a radius of curvature of 0.5-2 mm.

Legs 16 can tilt backward (towards posterior portion 12) and inward (towards device 10 symmetric centerline) at various angles controlled by bends 20 and 22 and additional bend in each leg 16 (30 in Figure 2B). Device 10 is constructed such that the forces on ring-like body 12 during the heart cycle are in the range of 0.02-3 N).

Figures 2A-D illustrate various views of device 10 and provide exemplary dimensions for the various device portions described hereinabove as well as illustrate the overall device 10 geometry. The backward bend of legs 16 is shown in Figure 2A, while Figure 2B show the inward bend of legs 16 which is determined by bend 22 and bend 30 (at a mid-portion of each leg 16). Bend 30 can be 5-20 degrees and is at the same distance from ring-like body 11 in each leg 16 or at different distances. Figure 2B illustrates a device 10 in which bends 30 are at the same distance (14.9 mm) from ring-like body 11.

The embodiment of device 10 shown in Figures 2A and 2C-D is asymmetric with respect to the extent each leg 16 tilts backward. Such asymmetry is demonstrated by the difference in tilt shown in Figures 2A and C and can include a 5-20 degree difference between the backward angulations of legs (10 degree difference between legs 16 shown in Figures 2A and C).

Embodiments of device 10 can also include legs that are angled at several points along their length (see, for example, Figures 2B, 5C and 7B). Such angle points can provide both medial and posterior tilting (angulation) of the legs. A first angle can tilt the legs medially (inward) at an angle less then 90 degrees (70-85 degrees). A second angle of 60-85 degree can be introduced mid leg about 2-10 mm from the first angle point. To avoid interference between the legs and the leaflets, posterior angulation can be achieved with one or more angle points. The posterior (backward) angle between the legs and ring-like body (and annular plane) can be between 30 and 70 degrees and is derived from the leg height and length (see Example 3). The length of the legs are related to the deepest point of the ring (the nadir) where the distance from that point can range between 5 mm posterior to the nadir and 7 mm anterior. When the present device is implanted at the annulus, the bridge interconnecting the legs should be positioned between 0 and 10 mm from the deepest point of the posterior annulus. The native annulus and the differences of planes of the trigons in comparison to the posterior annulus cause the device to tilt/bend anteriorly.

The portion of device 10 which resides in the left atrium (posterior portion 12 and anterior portion 14 co-planar with the valve annulus) can be anchored to the valve annulus using sutures staples T-anchors and the like, as in common surgical procedure. In order to facilitate such anchoring, portions of device 10 can be covered with a tubular cuff (sleeve) in order to stabilize the anchoring device (e.g. suture) with respect to device 10. Figures 3A-F illustrate various views of device 10 which includes a tubular cuff 32 covering ring-like body 11 and a tubular cuff 34 covering bridge 18.

Tubular cuffs 32 and 34 can be fabricated from a polymer or a fabric or a combination thereof (intermixed or at different layers). Such a polymer or fabric can be selected suitable for promoting tissue ingrowth. Examples of polymers include silicone and polyurethane which can be over-molded or coated to a final diameter of 1.2-2 mm while examples of suitable fabrics include knitted, braided or woven PET, polyethylene, terephthalate polyester with a thickness of 0.2-0.6 mm.

The legs 16 can be also be partially or fully covered with any of the above polymers or fabrics.

Figure 3G illustrates a device 10 configured as a closed ring, with a roughly D- shaped ring-like body 11 having posterior and anterior portions (12 and 14 respectively). In this configuration, legs 16 are attached directly to the ring-like body 11 and descend to form bridge 18 as described above. The manner in which legs 16 are attached to ring-like body 11 can also be implemented with an open ring such as that shown in Figures 3A-F.

Device 10 positioning at the mitral valve is shown in Figure 4. Ring-like body 11 is positioned at the atrial side of the valve while legs 16 and bridge 18 are positioned at the ventricular side of the valve. Ring-like body 11 is anchored to the posterior aspect of the mitral valve annulus (e.g. by suturing cuff 32 to annulus tissue) to secure device 10 in position. Artificial chords 40 can be attached between bridge 18 and posterior and/or anterior leaflets (e.g. sutured to cuff 34 and leaflets). Artificial chords 40 can be surgical sutures (e.g. polypropylene).

Figures 7A-B illustrate another embodiment of the present device in which eyelets 24 are angled above ring-like body 11. Figure 7 A is a side view of device 10 while Figure 7B is a posterior view of device 10. Experiments conducted by the present inventor have shown that the annulus of a diseased mitral valve does not always lie within a single plane but rather angles upwards at the regions of the commissures. In order to make sure that the ring-like body and contiguous open eyelets contact the annulus and do not distort it when sutured thereto, the open eyelet region of device 10 angles up from the plane of ring-like body. The angle selected is set with respect to the posterior end of ring-like body 11 (as shown in Figure 7A) and can be anywhere from 3-15 degrees (10 degrees shown in Figure 7A).

Implantation of device 10 of the present invention can be effected as follows. The mitral valve face is exposed from the atrial side and interrupted sutures are placed through the posterior mitral annulus to the region of the trigones securing the device to the circumference of the annulus. The leaflets and sub-valvular apparatus are evaluated by the surgeon and ruptured chords are resected if necessary. The location of artificial chord suturing at the leaflets is determined and marked. The annulus or the anterior leaflet is then sized (distance between trigones) using a dedicated sizer. An appropriately sized device is selected and device 10 is attached to a handle. The device is oriented with respect to the trigones using the handle such that bends 20 are aligned with the trigones and posterior portion 12 abuts the posterior aspect of the annulus. While maintaining device 10 in position, the surgeon determines the required length of artificial chords by measuring the distance between the tip of the prolapsed leaflet to bridge 18 using notches on the holder (chord length may also be predetermined by means of transesophageal echocardiogram before proceeding with surgery). Prior to suturing device 10 to the annuls a selected number of artificial chords are sutured at the desired location on bridge 18 via a double suture. The artificial chords are then passed through holes in the holder to prevent loss of free suture ends in the left ventricle. The anchoring sutures stitched through the annulus are threaded through the antero-lateral portion (near eyelets 24) of cuff 32 (covering ring-like body 11) and ring-like body 11 of device 10 is secured against the valve. The holder is detached from device 10 and the artificial chords are retrieved via the handle. The sutures are tightened and knotted around the ring, starting with the sutures placed at the commissures. The artificial chords are sutured to the leaflets. Excess of the sutures, after anchoring the valve and leaflets are resected. When the chordae causing leaflets tethering, such as in ischemic disease, the culprit chordae can be resected and replaced by artificial chords. Alternatively, to restore leaflet coaptation the papillary muscle can be pulled and anchored to bridge 18, such that the native chordae do not tether the leaflets.

Another way of chordate implantation can be done in a continuous running fashion passing through the bridge and leaflet for part or all length of the treated free margin leaflet. The entire posterior leaflet can be sutured to bridge 18 to disable movement. Under such conditions, coaptation will be between the anterior leaflet and a "wall" formed by the posterior leaflet. Alternatively, a suture can be threaded through bridge 18 and the free margin of the diseased leaflet. Regardless of approach, once the leaflets are sutured to bridge 18 the valve is tested for competency. Valvular competency is tested by injecting saline into the left ventricle through the mitral; orifice and observing coaptation of the leaflet. If needed, the length of the artificial chords is revised by moving the knot. Once the procedure is completed, transesophageal ultrasound is performed to evaluate valve performance.

The above general approach can be varied/modified based on mitral valve pathology - degenerative or functional.

In correction of degenerative disease, prior to ring fixation to the native annulus valve, one or both leaflets can be fixed directly to the bridge, using a surgical suture. Such a procedure can be done especially when excessive leaflet tissue is noted like in Barlow disease.

Alternatively, when artificial chordae are indicated for use, the chordae are first attached to the bridge and then anchored at the right position in the leaflet. Such a procedure is indicated when chordae are torn or elongated. The bridge can be used to anchor one or both leaflets.

When more than one pair of chordae are required, the artificial chordae can be passed in a running fashion between the bridge and free margin of the leaflet and finally fixed at the two extremities. In such a procedure less knots are required, and equal tension on the chordae and leaflet can be achieved.

In functional disease typically the valve apparatus is intact and the valve dysfunction is related to left ventricle geometry changes which result in changes in papillary muscles position. Following ischemia or myocardial infarction or when the left ventricle is dilated, papillary and native mitral chordae pull the leaflets into the left ventricle cavity, resulting in mitral regurgitation. The tethering, most frequently can be noted in the postero-medial papillary muscle affecting both anterior and posterior leaflets corresponding to the P3 and A3 leaflet regions. To repair such pathology, the fibrotic end of the culprit papillary muscle can be detached completely or partially and reattached to the bridge. Another surgical technique to eliminate tethering is to pull, via suture, the whole papillary muscle (papillary muscle suspension) and attach it to the bridge. To treat functional mitral regurgitation, the dilated/infarcted left ventricular wall can be suspended via trans-wall suture anchoring to the bridge. The entire myocardium wall is pulled toward the mitral annulus, thus eliminating the tethering of the mitral valve apparatus.

It will be appreciated that in approaches in which the muscle is directly attached to the bridge, movement of the leaflets is still enabled.

Alternatively, one or more chordae can be detached and new artificial chordae can be attached between the bridge and free leaflet margin.

As used herein the term "about" refers to ± 10 %.

Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art upon examination of the following examples, which are not intended to be limiting.

EXAMPLES

Reference is now made to the following examples, which together with the above descriptions, illustrate the invention in a non limiting fashion.

EXAMPLE 1

Ex-vivo testing of prototypes

Several prototypes were constructed and tested ex-vivo on a porcine heart (about

500 gm) mounted on a mock loop passive beating heart test platform. The heart was inflated with water and the anatomy was measured using common approaches. The valve was measured using a mitral valve sizer, the prototypes were placed on the valve annulus and the LV was filled with water.

The prototypes were constructed with various combinations of the following dimensions:

(i) Leg length - 15, 17.5 and 20 mm

(ii) Inward angle between legs - 30° and 15°

(iii) Backward angle between legs and annular plane - from 90° to 60° Table 1 below lists the seven prototypes constructed and tested (IP003, IP0032-39)

Table 1

Several insights were gained from these ex-vivo experiments. The length of the legs (and distance between the bridge and ring-like plane) should be selected such that coaptation is above the bridge and the legs do not touch the papillary muscle. A bridge to ring-like plane distance of 20 mm was found to be optimal in these experiments. The legs should angle backward (to posterior to ring-like body) such that they angle towards the heart wall in order to enable free movement of the Anterior leaflet. An inward angle of 10° was found to be optimal in these experiments.

EXAMPLE 2

Evaluation of additional parameters

A second set of experiments was conducted with the prototypes of Example 1.

These experiments were designed to further evaluate the back angle of the legs_[70 or 80 degrees), use of a backward bend in legs (at mid portion), use of inward bend in legs (at mid portion). Three prototypes were tested (shown in Figures 5A-C). Each of these prototypes was covered with fabric cuffs as is shown in Figure 8. No advantages were observed to the backward bend in the legs. The inward bend was found to be advantageous in that the legs and bridge avoid contact with the papillary muscle.

EXAMPLE 3

Bridge position

Experiments conducted by the present inventor have emphasized the importance of the position of the bridge with respect to the ring-like body. Since mitral valve anatomies vary between patients, some variability in the position of the bridge is expected. By modeling of the mitral valve, the present inventor has been able to determine the variability needed in bridge position that can provide the aforementioned functionality of the present device in a wide range of patient anatomies. As is shown in Figures 6A-C, the position of the bridge can be determined by positioning the present device with respect to a virtual rectangular space. The VRS is 15 mm in height, 25 mm in length and 9 mm in width and is positioned 5 mm below the plane of the ring-like body (Figure 6A) with a 2-5 mm posterior offset thereto (Figure 6A). The position of the bridge is effected by the length and angle of the legs. The backward angle of the legs is derived from the length of the legs and their distance from the anterior end of the ring-like body (i.e. the distance where the base of the legs starts).

EXAMPLE 4

In-Vivo pig testing

A single prototype having an asymmetric backward bend in the legs (70 and 80 degrees), and an inward bend to the legs at the annular plane and midway down the legs (similar to that shown in Figure 5B) was constructed and tested in pigs. The prototype (shown in Figure 8) included a fabric cuff on the bridge and ring-like body.

A 100 kg porcine was sedated and the chest cavity was opened via a midline sternotomy approach. Pre-operative ultrasound was performed to assess MR. Heparin was administered and following right atrium cannulation for vein return and ascending aorta cannulation for antegrade perfusion, a cardiopulmonary bypass was established. The Mitral valve was exposed via the Left Atrium and sutures were placed at the circumference of the posterior side of the annulus. The valve size was measured using a sizer and an intra-commis sural approach. The appropriate device size was selected and sutures were placed around the annulus and passed through the outer side of the polyester cuff of the device. The device was positioned against the valve annulus and the sutures were knotted at the trigones in order to assure correct positioning. Ultrasound was performed following the implantation procedure to assess valve function. In the second phase of the procedure, two chordates were cut at P2 to induce MR. Following MR inducement, two artificial chords were attached from the bridge of the device to the leaflets.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.