The present invention relates to devices and methods for repair of heart valves. More specifically, the invention relates to devices and methods for repairing mitral valve prolapse by replacement of chordae tendineae. Devices and methods for repairing mitral valve prolapse in general are known, e.g., from EP 2 548 534 A1
, US 2005/004668 A1
, and EP 2 198 806 A2
The mitral valve is one of the four valves of the heart having a complex structure. Various elements in the valve must function in a coordinated manner to cause blood to flow through the valve in an appropriate fashion. The mitral valve consists of two leaflets (anterior and posterior) that are attached to a fibrous ring (i.e., the annulus). The leaflets are anchored to papillary muscles in the wall of the left ventricle by a number of chordae tendineae (see, e.g., Figure 1). As shown in Figures 1 and 2, a normal mitral valve annulus 10 has a posterior region and an anterior region situated between two trigones, which are fibrous structures that form part of the base of the heart. Under normal conditions, during the contraction phase of the heart (i.e., systole), the two leaflets come together (i.e., coapt) and close the valve, which inhibits blood flow from the ventricle into the aorta (i.e., regurgitation). The coaptation of the valve leaflets typically occurs at (or near) the level of the fibrous ring, in part due to the chordae tendineae which restrict the leaflets from rising above that level.
In mitral insufficiency of a degenerative origin, closure of the valve is insufficient because one of the leaflets (or both) moves above the plane of the annulus at least partially into the left atrium, causing what is commonly referred to as prolapse of the leaflets. One cause of prolapse is elongation or rupturing of one or more of the native chordae tendineae. One common technique for prolapse repair consists of use of artificial cords (i.e., "neocords"), often made of polytetrafluoroethylene (PTFE), to replace defective native chordae tendineae. These neocords are connected between the papillary muscles and a free edge of the leaflets and thus perform the function of the native chordae tendineae.
In mitral insufficiency, the valve annulus is often also dilated. In cases of severe mitral insufficiency, the patient often must undergo intervention to repair the valve or to replace the valve with an artificial valve prosthesis. A valve repair procedure typically has one or more of the following objectives: to restore the mobility of the leaflets without restriction or excess movement, to create an adequate coaptation surface or closure, and to remodel the shape and size of the dilated mitral annulus.
The invention relates to a prosthetic device for repairing a mitral valve and is defined by the appended claims. According to various embodiments, the present invention provides a device that addresses two significant challenges associated with implanting neocords, namely determining the length required for optimal functionality and attaching the neocords to the native valve leaflets. According to some embodiments, the present invention is an annuloplasty device or an annuloplasty delivery device, which includes a plurality of reference elements, either separate or on a removable strip attached to the device, for the fixation of neocords thereto. The reference elements extend within the lumen of the annuloplasty device or on the delivery device such that they are capable of receiving such neocords. These reference elements serve to establish the proper length of the neocords that are to be attached to mitral valve leaflets. This neocord length sizing criteria is based on the well established clinical concept that the length of the artificial chords is similar to the distance between the tip of the papillary muscle and the annulus plane level.
Advantageously, the device allows the proper length of the neocords to be established during an operation for the repair of a prolapse of the mitral valve. No pre-measurement of the implanted neocords, or use of a tool to pre-measure, is required. The invention makes it possible to have reliable and reproducible results in determining the length of the neocords. Furthermore, the reference element function to prevent knots used to attach the neocords to the native leaflets from slipping. The reference elements are then removed or cut away, leaving the knots in place.
While multiple embodiments are disclosed, still other embodiments of the invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic, sectional view of a portion of a heart including a mitral valve;
Figure 2 is a schematic view of a mitral valve with two leaflets;
Figure 3 is a plan view of a prosthetic device according to an embodiment of the invention;
Figure 4 is a schematic, cross-sectional view of a portion of a native mitral valve and annulus in which a prosthetic device is located according to an embodiment of the invention;
Figure 5 is a close-up view of portion A of Figure 3;
Figure 6 is a close-up view of a reference element being cut according to an embodiment of the invention;
Figure 7 is a plan view of a prosthetic device according to an example;
Figure 8 is a close-up view of portion B of Figure 7;
Figures 9A-9C are three schematic views showing steps in the application of a prosthetic device according to an example;
Figures 10A-10D are schematic views showing steps in the application of a prosthetic device according to another example;
Figure 11 is an exploded, perspective view of an annuloplasty ring in combination with a holder according to an embodiment of the invention;
Figure 12 is a bottom view of an assembled annuloplasty device and holder according to an example; and
Figure 13A is a bottom view and Figure 13B is a top view of an assembled annuloplasty device and holder including suture loops according to an embodiment of the invention.
While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.
In the following description, numerous specific details are given to provide a thorough understanding of various embodiments. The embodiments can be practiced without one or more of the specific details, or with other methods, components, or materials. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
Figure 1 shows a schematic, sectional view of a portion of the heart including a mitral valve 10. As shown, the mitral valve 10 is generally located between the left atrium 12 and the left ventricle 14.
Figure 2 shows a schematic top plan view of a mitral valve 10. As shown in Figures 1 and 2, the mitral valve 10 includes an annulus 16 and two leaflets, which are an anterior leaflet 18 and a posterior leaflet 20. The anterior leaflet 18 is typically coupled to the annulus 16 at least in part at the location disposed between the left fibrous trigone (LFT) 22 and the right fibrous trigone (RFT) 24. As shown, in a properly functioning heart valve the free edges of the anterior leaflet 18 and the posterior leaflet 20 generally come together and coapt during systole to form a coaptation zone 26. The leaflets 18, 20 are also attached to papillary muscles 28 in the left ventricle 14 by multiple chordae tendineae 30.
Figure 3 shows a prosthetic device 50, according to exemplary embodiments of the invention. According to various embodiments, the prosthetic device 50 is an annuloplasty device designed for the repair of a mitral valve annulus. As shown, the prosthetic device 50 has an open configuration and is generally shaped, for example, like a letter "C." According to other embodiments, the annuloplasty device has a closed configuration and is generally shaped, for example, like a letter "O" or a letter "D." According to various embodiments, the size and shape of prosthetic device 50 are selected to generally match the configuration of a patient's mitral valve annulus.
In various embodiments, the prosthetic device 50 includes an elongate element 52 including reference elements 54. Although other configurations are contemplated, the elongate element 52 may comprise a central core, and an exterior covering (not shown). The central core can be made of a material that is suitable for a desired stiffness. The central core may comprise a rigid, semi-rigid or flexible material, or may be a combination of rigid, semi-rigid, and/or flexible materials and/or portions. The central core preferably may comprise (e.g., consist essentially of) a molded polymeric element. One exemplary material for the central core is a silicone material, which is flexible. According to exemplary embodiments, the core may be formed of one or more of the tubular members disclosed in US Patent 8,034,103
One exemplary material for the exterior covering is a polyester material. The exterior covering may comprise a knitted polyester (e.g., Dacron™) fabric, although woven, nonwoven (e.g., spun-bond, melt-blown, staple fiber matrix, etc.) or braided fabrics are also contemplated. The exterior covering may optionally be provided with any of various biocompatible coatings. According to exemplary embodiments, the coating may be any of the various coatings disclosed in US Patent 5,423,886
The elongate element 52, according to various embodiments, may have any of a variety of cross-sectional shapes, including for example a generally circular cross-sectional configuration. According to other embodiments, the cross-sectional shape may be one or more of square, circular, rectangular, elliptical, triangular, or other similar shapes. Different cross-sectional shapes can be used to impart varying degrees of bending or torsional stiffness depending on the bending/twisting plane with respect to a section modulus. Also, according to some embodiments, the cross-sectional shape at different locations around the circumference of the elongate element 52 varies.
The prosthetic device 50 preferably has a low profile (e.g., cross-sectional thickness of about 3 mm). With this preferred low profile, the device 50 may reduce the potential for stenosis and turbulence within the valve, as well as onset of thrombus by minimizing the restriction or disturbance of blood flow through the valve.
Exemplary dimensions of the elongate element 52 may include a length of approximately 63 mm, which fits most adult patients. However, other lengths of elongate element 52 are also contemplated. According to some embodiments, a variety of sizes of elongate bands 52 having a variety of different length are packaged together such that a surgeon may select a prosthetic device 50 best suited for a particular patient.
As shown in Figure 3, one or more reference elements 54 are located on or attached to elongate element 52. The reference elements 54 are separated from each other and protrude radially inward from the elongate band 54 towards an inner lumen 56. In some embodiments, the reference elements protrude radially inward in the same (or about the same) plane as the upper surface of the prosthetic device 50. In other embodiments, the reference elements protrude radially inward in the same (or about the same) plane as the lower surface (i.e., the surface in contact with the annulus) of the prosthetic device 50. In various embodiments, the reference elements 54 extend or protrude radially inward into the inner lumen 56, such that the reference elements are accessible by a suture needle (or other surgical instrument) during the mitral valve repair procedure.
According to various embodiments, the reference elements 54 are configured to receive and couple with artificial chordae tendineae (i.e., neocords). In various embodiments, the reference elements 54 are sized and shaped to allow neocords to be individually knotted or tied to the reference elements 54. Figure 4 shows the prosthetic device 50 attached to the mitral valve annulus 16. As shown, the elongate element 52 disposed above and attached to the annulus 16, with the reference elements 54 extending radially inward toward a center of the valve annulus. As shown in Figure 4, the reference elements 54 are disposed at or about the plane of the annulus 16. According to other embodiments, the reference elements 54 are disposed slightly above or slightly below the plane of the annulus 16.
Once the physician has attached the prosthetic device 50 to the annulus 16, the physician may connect neocords between the papillary muscles and the valve leaflet. During this procedure, the physician extends the neocord through the valve leaflet and ties the neocord onto the reference elements 54. Any excess portion of the neocord may then be cut off to leave a correct length for repair of prolapse of the leaflet or leaflets. The physician may then cut the reference elements 54 to free the neocords, which remain attached to the leaflet.
Figure 5 shows an enlarged portion of the prosthetic device marked "A" in Figure 3. Reference element 54 is shown including a needle-passing lumen 58. Reference element 54 in Figure 5 is also shown as comprising a thread, or suture, coupled (e.g., fixed directly) to the elongate element 52. In examples not forming part of the invention, other suitable configurations of reference elements 54 are contemplated that are able to then be cut or opened or otherwise removed in order to release knotted neocords having a desired length.
Figure 6 shows an enlarged view of another embodiment of a reference element 54 being cut open. As shown, the physician may use a blade (e.g., scalpel or scissors) to cut or separate a portion of the reference element 54 to allow separation of a neocord tied to the reference element 54.
Figure 7 shows an example of a prosthetic device 60. As shown, the prosthetic device 60 includes an elongate element 62 having a shape similar to a letter "D." According to various configurations, the prosthetic device 60 may have an open configuration and is generally shaped, for example, like a letter "C." According to other examples, the prosthetic device 60 has a closed configuration and is generally shaped, for example, like a letter "O" or a letter "D." According to various embodiments, the size and shape of prosthetic device 60 are selected to generally match the configuration of a patient's mitral valve annulus.
As shown in Figure 7, a plurality of reference elements 64 are included on a strip 66 that is coupled to the elongate element 62. The strip 66 is releaseably coupled (e.g., by sutures) to the elongate element 62. During use, after attaching the neocords to the reference elements 64, the physician may separate the strip 66 and remove it from the elongate element 62. In various implementations, the physician my also cut each of the reference elements 64 to free the neocords from the strip 66.
Figure 8 shows a close-up of one reference element 64 from Figure 7 (encircled portion marked "B" in Figure 7). The close-up view shows that the reference element 64 is part of a strip 66 that is releasably attached to elongate element 62. The strip 66 may be made of any suitable material that may be easily removed from elongate element 62. The strip 66 may be attached to elongate element 62 by an adhesive material or any other suitable means, prior to its removal. According to other embodiments, the strip 66 is attached to the elongate element 62 in a non-releasable manner.
The use of a prosthetic device in accordance with the invention (e.g., the prosthetic device 50 shown in Figure 3) is detailed below with reference to Figures 9A-9C, which provide schematic illustrations of steps in the use. As shown in Figure 9A, a prolapsing segment 68 of a leaflet of mitral valve 10 is first identified. One end of a neocord 70 (Figure 9B) is stitched to a fibrous head 72 of the papillary muscle 28, leaving the opposite end of the neocord 70 free. The physician then performs an annuloplasty of the posterior ring of the mitral valve 10, with the elongate element 52 of the prosthetic device 50 being anchored at its ends to the trigones. Next, the free end of the neocord 70 is then tied to (or knotted onto) one reference element 54, as shown in Figure 9B. Any additional or excess length of the neocord 70 that extends beyond the knot may then be cut off. The reference element 54 is next cut open, freeing the knotted end of the neocord 70 from the elongate element 52.
According to various methods of using the device, the free end of the neocords 70 is simultaneously coupled (e.g., tied or knotted) to both the reference element 54 and the corresponding (e.g., prolapsing) segment 68 of the leaflet. In these methods, the physician then opens (e.g., by cutting with a scalpel) the reference element 54 such and frees the end of the neocord from the reference element 54, such that the neocords remains coupled to the leaflet.
Figures 10A-10D illustrate an exemplary method of using the prosthetic device 50. As shown in Figure 10A, a needle is used to attach a first end of a neocord 70 to a papillary muscle 72. Next, a needle is used to extend an opposite end of the neocords 70 through a prolapsed segment 68 of a leaflet of the mitral valve. As shown in Figure 10B, the neocord 70 extends through the leaflet then through a reference element 54 of the prosthetic device 50. Next, as shown in Figure 10C, the neocords 70 is extended again through the proslapsed segment 68 of the leaflet. The end of the neocord 70 is then pulled to remove the slack from the neocord 70 between the papillary muscle 72 and the reference element 54. Next, the neocords 70 is knotted at or near the leaflet segment 68 to establish and fix and operable length (i.e., the distance from the papillary muscle 72 to the location of attachment to the leaflet segment 68) of the neocord 70.
The process described above with reference to Figures 10A-10C is repeated for each desired neocords 70. The number and spacing of neocords 70 is determined by the physician, based on the nature of the prolapse present in a particular patient. Once the physician has completed the attachment process for the desired neocords 70 (or for the desired plurality of neocords 70), as shown in Figure 10D, the neocords 70 are separated from the reference elements 54.
According to the invention wherein the reference elements 54 are formed by a thread, the physician may pull on the thread forming the reference elements. This pulling force removes the thread from the prosthetic device 50 and, during this process, the thread pulls through and thus separates from the knots formed in the neocords 70. In this way, each neocords 70 is separated from the reference element 54, but remains attached to the prolapsed segment 68. According to other methods the reference element 54 is opened (e.g., cut) to allow the neocord 70 to exit from the reference element 54, which is then removed from the patient. In this way, the neocord 70 now extends between the papillary muscle and the prolapsed segment of the leaflet, with a length that has been determined using the prosthetic device 50.
Another embodiment of the invention is shown in Figure 11. One embodiment of a holder 200 for use with an annuloplasty device 202 (for example) is illustrated in Figure 11, and designated in its entirety by the reference numeral 200. The holder 200 comprises an elongate handle 204 and a retaining member (e.g., a plate or annular frame) 206. The retaining member 206 may, for example, be alternatively used to retain an annuloplasty device having an alternative shape. More generally, the retaining member 206 could be described as a holding member. The purpose of the holder 200 is to deliver and retain the annuloplasty device 202 at a mitral valve annulus during a implantation procedure.
The retaining member 206 is selectively mounted on the handle 204. The retaining member 206 of the holder 200 is adapted to retain the annuloplasty ring 202 shown during implantation of the annuloplasty ring 202. Thus, in accordance with the one embodiment, the general perimeter shape of the retaining member 206 corresponds generally with a shape of the mitral valve annulus. Alternatively, of course, a perimeter shape of the retaining member 206 can vary from that shown. According to various embodiments, the retaining member 206 is formed of transparent biocompatible thermoplastic or synthetic resin material, such as polycarbonate or polysulfone. The handle 204 may be of metal, such as an anodized aluminum alloy or stainless steel, or a suitable thermoplastic, thermoset or synthetic resin material.
The handle 204 of the holder 200 may be, for example, designed for a snap-fit engagement in the retaining member 206. The snap-fit engagement may be provided by a plurality of cantilever spring fingers 208 that are received in a slot 210 in the retaining member 206. This snap-fit mechanism allows the handle 204 to be attached to the retaining member 206 by surgical staff. Alternatively, any suitable temporary or permanent means for attaching the handle 204 and retaining member 206 may be employed.
According to various embodiments, the annuloplasty device 202 is mounted on the holder 200 at time of manufacture, and the assembly (or combination) is provided as a sterile unit. In one embodiment, and as illustrated in Figures 11 and 12, the retaining member 206 is adapted to receive a suture 212 in a plurality of spaced passage pairs 214 that are employed to secure the annuloplasty ring 202 to the retaining member 206. Each passage pair 214 includes two holes extending transversely through the retaining member 206. Each of the holes is adapted to allow passage of the suture 212. Further, as shown in Figure 11, the holes comprising any one of the passage pairs 214 are separated by a section of the retaining member 206. In other words, each of the passage pairs 214 includes two distinct holes, and is not a continuous slot. With this configuration, the suture 212 can be threaded around, and thus engaged by, the retaining member 206 as shown in Figure 11 and as also show in Figures 13A and 13B.
The above-described mounting technique is one of several known technique for securing the annuloplasty ring 202 to the retaining member 206. Alternative configurations/techniques can be employed for selectively mounting the annuloplasty device 202 to the retaining member 206. In some embodiments, if a suture is used, it is sewn to the annuloplasty device 202 at discrete and spaced apart positions from one another. Final assembly of the annuloplasty device 202 to the retaining member 206 is illustrated in FIGS. 13A and 13B. As depicted by the bottom view (FIG. 13A), the annuloplasty ring 202 is effectively mounted to a bottom surface of the retaining member 206.
As shown in Figures 12, reference elements 216 are associated with the retaining member 206. Such reference elements 216 may be separately attached to the retaining member 206 or may be part of an integrated strip 218 of reference elements 216 that is attached to the retaining member 206. The reference elements 216 are oriented toward the inner lumen of the annuloplasty device 202 and retaining member 206. Also, the reference elements 216 can have all the shapes and configuration as those described above with regard to other embodiments of the invention. In some embodiments, the reference elements 216 are coupled to a lower (i.e., closer to the valve annulus) surface of the retaining member, such that the reference elements are located at (or near) the plane of the annulus 10. In other embodiments, the reference elements 216 are coupled to an upper (i.e., further from the valve annulus) surface of the retaining member, such that the reference elements are located slightly above the plane of the annulus 10.
The holder 200 and annuloplasty ring 202 together may be directed to an implant site via maneuvering of the handle 204. Once at the implant site, the annuloplasty ring 202 is connected to the valve annulus with implanting sutures, which are placed, tightened, and tied. Before the holder 200 is removed, neocords are attached, at a first end, to a papillary muscle and, at a second end, to the reference elements 216 and to a corresponding portion of the leaflet. The reference elements 216 are then cut or removed. Next, the sutures 212 connecting the device 202 to the retaining member 206 are cut at the passage pairs 214, releasing the suture 212, and the holder 200 is removed.
Figures 13A and 13B show an alternative embodiment of an annuloplasty system 300 including an annuloplasty ring 202 coupled to a holder 206. As shown in Figure 13A, the annuloplasty ring 202 is coupled to the holder 206 using a plurality of sutures 212 extending from the holder 206 circumferentially around the annuloplasty ring 202. As further shown in Figure 13B, the holder 206 includes a plurality of loops 216 extending radially inwardly from the holder 206. While the embodiment of Figure 13A includes four loops 216, other embodiments may include more or fewer loops 216. According to various embodiments, the loops 216 are disposed at circumferential locations corresponding to prolapsing segments of the native valve leaflets. According to other embodiments, however, the loops 216 may be disposed closer to the ring (and thus closer to the valve annulus) or the loops 216 may be disposed further from the ring (and thus further from the valve annulus). According to various embodiments, the loops have a diameter (and thus an extended length) sufficient to allow the loop to extend to a location at or near the valve annulus. According to various embodiments, the loops extend inwardly (e.g., away from an inner surface of the holder 206) a distance of from about 0.5 to about 4 mm. In various embodiments, the loops extend inwardly a distance of from about 1 to about 2 mm.
During use of the annuloplasty system 300, the physician may first position the annuloplasty holder 206 and ring 202 at a location adjacent an upper (i.e., outflow or atrial) portion of the valve annulus. The physician then sutures the ring 202 to the valve annulus. In addition, the physician attaches one or more neocords between an appropriate papillary muscle and a loop 216. According to various embodiments, the attachment to the loop 216 is made with a simultaneous attachment to a prolapsing segment of the mitral valve leaflet, such as for example by passing the neocords through the leaflet then tying or knotting an end of the neocords to the loop 216. During this process, the neocords may be attached with a small amount of tension, such that the loop 216 is caused to take an extended configuration. In this fashion, the diameter (or length) of the loop 216 determines the level at which the prolapsing segment of the leaflet will be allowed (by the neocords) to extend. Upon attaching the neocords to the loop (and the corresponding portion of the leaflet), the loop is cut or removed and the neocords remains attached to the leaflet. According to various embodiments, the holder and loop are then removed together.