A naturally designed mitral valve prosthesis

Abstract

A mitral valve prosthesis to be implanted in the heart includes an asymmetric ring whose dimensions are designed to simulate the patient's natural mitral valve ring; an anterior flexible leaflet and a posterior flexible leaflet, which are suspended from the asymmetric ring and are configured to substantially engage each other; and at least four groups of cord-like structures, each group of cord-like structures being attached to the anterior leaflet or the posterior leaflet at a first end and to a cap at a second end, the cap being configured to attach to a papillary muscle of the heart at the other end of the cap.

Description

Background Art

[0001] The mitral valve or left atrioventricular valve, also known as the mitral valve (i.e., a valve comprising two leaflets), is a valve in the heart that separates the left atrium from the left ventricle. The mitral valve allows blood to flow from the left atrium into the left ventricle during ventricular diastole, while preventing retrograde flow during systole. The naturally occurring mitral valve includes the annulus, two leaflets, atrial muscle, chordae tendineae, papillary muscles, and ventricular muscle.

[0002] A mitral valve replacement is a procedure designed to replace a valve that is diseased or no longer functioning. During a mitral valve replacement procedure, the patient's mitral valve is removed and replaced with a prosthesis. The unique configuration of the mitral valve presents challenges in creating a durable and properly functioning mitral valve prosthesis.

[0003] Both biological and mechanical mitral valve prostheses are commercially available. Both biological and mechanical prostheses have a rigid, rounded shape, compared to the soft tissue and asymmetric shape of the human mitral valve. An additional disadvantage of mechanical valves is that blood tends to clot on the mechanical components of the valve and render the valve incapable of functioning properly. Patients using mechanical valves must take anticoagulants to prevent the risk of blood clots forming on the valve, which can lead to stroke. Biological valves have a reduced risk of blood clot formation but have more limited durability and require more frequent replacement than mechanical valves. Biological valves, like mechanical valves, include a rigid metal frame and feature a metal ring covered with silicone or other synthetic material to allow the passage of implant sutures.

[0004] Currently available mitral valve prostheses are typically constructed in a non-natural, circular manner and are typically made of rigid materials. They are also typically characterized by three symmetrical leaflets, while the natural human mitral valve includes only two leaflets, a larger anterior leaflet and a smaller posterior leaflet. Due to their rigidity and non-natural structure, such mitral valve prostheses distort the natural anatomy of the heart. The myocardium surrounding these prostheses does not recover well after the implantation procedure. The prosthesis lasts an average of only 7-10 years, causing the patient to require a second, and sometimes a third, surgery during their lifetime, which repeatedly exposes the patient to the high risks of open heart surgery.

[0005] Commercially available prostheses do not achieve the hemodynamic performance of a healthy native human mitral valve. This results in substantial energy loss to the left ventricle, significant strain over time, and eventual heart failure and other adverse phenomena.

[0006] Some other available mitral valve prostheses may be formed by reinforcing a homograft as described in US 6,074,417, which means that the physician needs to scan valves of various sizes to find the best match for each patient, while sacrificing the animal from which the valve was taken. Other available mitral valve prostheses may also be formed by sewing multiple layers of pericardium to each other, as described in US 5,415,667, which may result in clotting in areas where multiple suture lines are present.

[0007] Other forms of atrioventricular valves, including mitral valves, are disclosed in U.S. Pat. No. 6,358,277, in which a template of membrane material is sutured to the annulus of the patient. Such valves are characterized by a high and non-naturally shaped ring, making the circumference of the prosthetic valve bulky and elevated like a liner. In addition, the template is provided in a standard size, which then must be trimmed to fit the patient. Summary of the invention

[0008] A prosthetic valve designed to simulate a patient's native mitral valve is provided. Two flexible leaflets and an asymmetric and flexible ring can move with the natural deformation of the myocardium during the heart cycle. A cord-like structure similar to the patient's natural chordae tendineae is included in the prosthetic valve to mimic the natural prevention of blood backflow into the atria and provide support to the left ventricle during contraction.

[0009] According to some embodiments, a mitral valve prosthesis to be implanted in a heart comprises:

[0010] an asymmetric ring sized to simulate a patient's native mitral valve annulus, the asymmetric ring being constructed of a flexible material that wraps onto itself toward the outside of the valve;

[0011] an anterior flexible leaflet and a posterior flexible leaflet, the anterior leaflet and the posterior leaflet depending from the asymmetric ring and configured to substantially engage one another;

[0012] Each of the anterior leaflet and posterior leaflet shapes are configured to mimic the shape of a native mitral valve, whereby the anterior leaflet and the posterior leaflet create an orifice through which blood flows in one direction; and

[0013] At least two sets of cord-like structures, each set of cord-like structures is attached to the anterior leaflet or the posterior leaflet at a first end and attached to a cap at a second end, the cap being configured to be attached to a papillary muscle of the heart at the other end of the cap.

[0014] According to some embodiments, the mitral valve prosthesis may further include an engagement surface continuing from each of the anterior leaflet and the posterior leaflet and attached to each set of cord structures; the engagement surface being configured to enhance sealing of the mitral valve prosthesis.

[0015] According to some embodiments, the asymmetric ring may further include at least two strands configured in a coiled coil structure.

[0016] According to some embodiments, the asymmetric ring includes two layers of material folded together to provide elasticity, and a third layer to provide structural stability.

[0017] According to some embodiments, the asymmetric ring may include two layers of bovine pericardium; and a third layer of glycine or proline to provide strength.

[0018] According to some embodiments, the layers may be connected together via sutures, staplers, staples, glue, or any combination thereof.

[0019] According to some embodiments, the asymmetric ring, the anterior and posterior flexible leaflets, the at least two cord-like structures, the cap, or any combination thereof can be made of bovine pericardium.

[0020] According to some embodiments, the leaflet shape may be extended by 1-5 mm to allow for better coaptation and cord attachment.

[0021] According to some embodiments, the leaflet shape can be designed in a semi-circular manner along half of the length of the anterior flexible leaflet and the posterior flexible leaflet, so that the two leaflets create an "S" shaped seal when coapted.

[0022] According to some embodiments, the mitral valve prosthesis may further include at least one secondary cord-like structure; and wherein the at least one secondary cord-like structure is attached to the middle portion of the posterior leaflet at one end and to the middle portion of the main cord-like structure at another end.

[0023] According to some embodiments, the at least two groups of funicular structures may be attached to an opening of the cap, the opening being located in the middle of the cap.

[0024] According to some embodiments, each of the at least two groups of cord-like structures can be attached to a middle portion of the anterior leaflet or the posterior leaflet to simulate a naturally occurring mitral valve.

[0025] According to some embodiments, the anterior leaflet or the posterior leaflet may be made of a single unit connected to the asymmetric ring and attached to at least two sets of cord-like structures.

[0026] According to some embodiments, the mitral valve prosthesis may further include an extension connected to the anterior flexible leaflet at one end and to at least two sets of cord-like structures at the other end, and configured to allow engagement between the anterior flexible leaflet and the posterior flexible leaflet.

[0027] According to some embodiments, a mitral valve prosthesis to be implanted in a heart may include:

[0028] an asymmetric ring sized to simulate a patient's native mitral valve annulus; the asymmetric ring being constructed of a flexible material that wraps onto itself toward the outside of the valve;

[0029] two leaflets suspended from the asymmetric ring, the leaflets being constructed on opposite sides along a cutout made of a material similar to that from which the asymmetric ring is constructed, wherein the cutout creates an orifice through which blood flows in one direction;

[0030] at least two sets of cord-like structures, each set of cord-like structures attached at a first end to one of the two leaflets and attached at a second end to the bundle;

[0031] and a cap attached to the at least two sets of cord-like structures at one end of the cap and configured to be sutured to a papillary muscle of the heart at the other end of the cap.

[0032] According to some embodiments, each set of funicular structures is attached to one of the two leaflets via an extension configured to allow coaptation between the two leaflets.

[0033] According to some embodiments, at least a portion of the at least two sets of cord-like structures comprise the patient's own native mitral valve chordae tendineae.

[0034] According to some embodiments, at least a portion of the at least two sets of cord-like structures include the patient's own native mitral valve chordae tendineae, and at least a portion of the patient's own native leaflets.

[0035] According to some embodiments, the asymmetric ring further comprises a radiopaque marker filament inserted within the coiled flexible material.

[0036] According to some embodiments, the mitral valve prosthesis also includes a suture made of a radiopaque suture material, the suture formed through the ring. According to some embodiments, a mitral valve prosthesis to be implanted in a heart includes: an asymmetric ring, the size of the asymmetric ring is designed to simulate the patient's natural mitral valve ring; the asymmetric ring is composed of a flexible material that is rolled onto itself toward the outside of the mitral valve; two leaflets suspended from the asymmetric ring, the leaflets are constructed on opposite sides of an incision made of a material similar to that used to construct the asymmetric ring, wherein the incision creates an orifice through which blood flows in one direction; at least two sets of cable-like structures, each set of cable-like structures is attached to one of the two leaflets at a first end and attached to a bundle at a second end; and a cap, the cap being attached to the at least two sets of cable-like structures at one end of the cap and being configured to be sutured to the papillary muscles of the heart at the other end of the cap.

[0037] According to some embodiments, each set of funicular structures is attached to one of the two leaflets via an extension configured to allow coaptation between the two leaflets.

[0038] According to some embodiments, each set of cord-like structures is composed in part of the patient's own natural mitral valve cord-like structures.

[0039] According to some embodiments, a method of manufacturing a mitral valve prosthesis may include:

[0040] Measure the size and shape of the patient's mitral valve via imaging methods;

[0041] cutting a replica of the subject's mitral valve from a single piece of material;

[0042] cutting an incision along the single piece of material, thereby creating an orifice for blood flow and two leaflets, one on each side of the orifice;

[0043] Measuring the length of the desired cable-like structure by imaging method;

[0044] attaching the cable-like structure to one of the two caps; and

[0045] A flexible ring is attached to the leaflets, thereby creating an entire mitral valve prosthesis that mimics the native mitral valve of the particular patient.

[0046] According to some embodiments, measuring the length of the desired cord-like structure may be performed simultaneously with measuring the size and shape of the subject's mitral valve.

[0047] According to some embodiments, the method may further include attaching an extension to each of the two leaflets to carry the cord-like structure prior to attaching the cord-like structure to one of the two caps.

[0048] According to some embodiments, the method may further comprise the step of adding a flexible material to the flexible ring, the flexible ring being formed from at least one layer of the flexible material and one layer of the material.

[0049] According to some embodiments, the method may further include adding a radiopaque material to the flexible ring, the flexible ring being formed from at least one layer of the radiopaque material and one layer of the material. According to some embodiments, the flexible ring may be attached to the leaflet using a radiopaque suture material.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1A and Figure 1B is a schematic diagram of an embodiment of the present invention. Figure 1A A prosthetic mitral valve is depicted in an open position and showing the chordae prior to attachment to the leaflets, according to some embodiments of the present disclosure. Figure 1B A prosthetic mitral valve is depicted in a closed position and showing the chordae after attachment to the leaflets, according to some embodiments of the present disclosure.

[0052] Figure 2 is a schematic diagram of an embodiment of the present invention implanted in a heart according to some embodiments of the present disclosure;

[0053] Figure 3 is a 3D reconstructed image of the mitral valve region in a three-dimensional CT image analysis software according to some embodiments of the present disclosure;

[0054] Figure 4 is a photograph of a 3D printed valve mold and a porcine pericardial mitral valve leaflet according to some embodiments of the present disclosure;

[0055] Figure 5 is a photograph of a prosthetic valve under in vitro testing according to some embodiments of the present disclosure;

[0056] FIG. 6A to FIG. 6B are schematic illustrations of a side view of an anterior leaflet and a posterior leaflet of a prosthetic mitral valve, respectively, and a top view of the leaflets when coapted to one another, according to some embodiments of the present disclosure;

[0057] Figure 6C is a schematic illustration of a top view of a mitral valve prosthesis looking down from the left atrium toward the left ventricle (during diastole, when the valve opens to allow blood to enter the left ventricle) in accordance with an embodiment of the present disclosure;

[0058] Fig.6Dis a schematic illustration of a single piece of material including an anterior leaflet and a posterior leaflet according to an embodiment of the present disclosure;

[0059] FIG. 7A to FIG. 7B is a cap for connecting a cord-like structure to a papillary muscle of a heart, and a heart valve prosthesis having two caps attached to the cord-like structure, according to an embodiment of the present disclosure;

[0060] FIG. 8A to FIG. 8B are schematic illustrations of possible positions of a funicular structure relative to a leaflet and a cross-section of the funicular structure when attached to a leaflet, respectively, according to some embodiments of the present disclosure;

[0061] FIG. 9A to FIG. 9B Schematic illustrations of a prosthetic mitral valve with two leaflets attached in an alternative design featuring a curved (ellipsoid / droplet) configuration so as to enlarge the articulation surface and possible articulation surface configurations, respectively, according to some embodiments of the present disclosure;

[0062] Fig.10 is a schematic illustration of a measured copy of a patient's mitral valve from a 2D or 3D echocardiographic image according to some embodiments of the present disclosure;

[0063] Fig.11 is a schematic illustration of the formation of a two-leaflet prosthesis according to some embodiments of the present disclosure;

[0064] Fig.12 is a schematic illustration of an opening formed along a leaflet portion according to some embodiments of the present disclosure;

[0065] Fig.13 is a schematic illustration of an echocardiogram or MRI scan of a patient's left heart chamber or ventricle according to some embodiments of the present disclosure;

[0066] FIG. 14A to FIG. 14B are schematic illustrations of a patient's left ventricle during diastole and during systole, respectively, according to some embodiments of the present disclosure;

[0067] FIG. 15A to FIG. 15B are schematic illustrations of extensions attached to the anterior leaflet and the posterior leaflet, respectively, according to some embodiments of the present disclosure;

[0068] FIG. 16A to FIG. 16B is a schematic illustration of a side view of a mitral valve prosthesis having an extension and an attached cord structure during diastole and systole, respectively, according to some embodiments of the present disclosure;

[0069] Fig.17 is a schematic illustration of attaching an asymmetric flexible ring to a periphery of a valve prosthesis to simulate a native valve annulus according to some embodiments of the present invention;

[0070] 18A to 18E Schematic illustrations of an elastic material to be inserted into a rolled valve annulus before and after the annulus is rolled thereon, respectively, according to some embodiments of the present disclosure, and

[0071] Fig.19 is a schematic flow chart illustrating a method for manufacturing a mitral valve prosthesis according to some embodiments of the present disclosure.

[0072] The foregoing will be readily understood from the following more particular description of example embodiments of the invention as illustrated in the accompanying drawings in which like reference characters refer to the same parts in the different views. The drawings are not necessarily to scale; emphasis instead being placed upon illustrating embodiments of the invention. DETAILED DESCRIPTION

[0073] Figure 1A and Figure 1B The mitral valve prosthesis of the present invention is shown in FIG. The mitral valve prosthesis 100 has a physiological shape similar to a natural human mitral valve. The mitral valve prosthesis includes a flexible asymmetric ring 1 and two flexible membranous leaflets 2 suspended on the asymmetric ring 1. The mitral valve prosthesis also includes two groups of cord-like structures 3 that mimic the tendons of the heart. Each group of cord-like structures is configured to be attached to the edge and / or body of the leaflet 2 at one end and converge into a fixing cap 8 at the other end. The fixing cap 8 is configured to be sutured to the papillary muscle of the left ventricle.

[0074] The mitral valve 100 is shown as having a cord-like structure 3. Figure 1A is not attached to leaflet 2 and is Figure 1B The cable-like structures 3 can be attached to the leaflets 2 before surgery, or they can be attached during surgery. For example, the attachments 9 between the cable-like structures 3 and the leaflets 2 can be sutures, or they can be integrally engineered. Figure 1A is shown as open and in Figure 1B In the closed state, the leaflets 2 are shown as being coapted.

[0075] Figure 2 The mitral valve 100 is shown implanted in the heart. The mitral valve 100 is shown implanted at the location of the native mitral valve annulus 12, adjacent to the aortic valve 6 on one side, where the root of the aorta 7 connects to the left ventricle, and against the opposing ventricular wall 5 on the other side. The cord-like structure 3 is shown attached to the papillary muscles 4.

[0076] The flexible ring 1 can be customized following an ultrasound examination of the patient's heart. In particular, a three-dimensional echocardiographic study can be performed to obtain detailed anatomical measurements and / or to present a three-dimensional model of the patient's heart, from which a customized mitral valve can be produced. The leaflets 2 and the cord-like structure 3 can also be customized based on ultrasound imaging of the subject's native mitral valve and surrounding anatomy. The customized mitral valve can also be made from data obtained from other imaging modalities that provide three-dimensional information, including cardiac CT and cardiac MRI. In this way, the mitral valve prosthesis of the present invention can be selected or designed to match the patient's specific anatomy.

[0077] The flexible ring 1 can be formed, for example, from an elastic annuloplasty ring. The leaflets 2 can be formed from natural materials or biocompatible composite materials that can resist clots and function similarly to the patient's natural leaflets and posterior leaflets. At least two sets of cord-like structures attached at one end to one of the two leaflets and at a second end to the papillary muscle are provided to function similarly to the patient's natural chordae tendineae. The cord-like structures 3 that tether the leaflets 2 to the patient's papillary muscles provide support to the left ventricular wall throughout the cardiac cycle and prevent the leaflets from opening into the atrial cavity.

[0078] The mitral valve prosthesis 100 including the flexible ring 1, the leaflet 2 and the cord-like structure 3 looks and behaves similar to a healthy natural mitral valve. In addition, the mitral valve prosthesis of the present invention can be made of natural materials and can avoid the inclusion of foreign matter, such as filling. Allograft materials and / or composite materials, including various combinations of allografts, xenografts and / or autologous transplant materials, can be used to make flexible rings, leaflets, cord-like structures and caps. The materials forming the valve ring and leaflets can include but are not limited to human, bovine or porcine pericardium, decellularized biological materials, woven biodegradable polymers incorporating cells, and extracellular materials. Biodegradable natural polymers can include but are not limited to fibrin, collagen, chitosan, gelatin, hyaluronic acid and the like. Biodegradable synthetic polymer scaffolds that can be infiltrated with cells and extracellular matrix materials can include but are not limited to poly (L-lactide), polyethylene, poly (lactic acid-co-glycolic acid), poly (caprolactone), polycyclic esters, poly (dioxysiloxane), poly (anhydride), poly (trimethylene carbonate), polyphosphazene and the like. The flexible ring can be further customized to provide individualized flexibility or rigidity for the patient.In addition, some components of the mitral valve prosthesis, including the cord structure 3, can be molded intraoperatively from the patient's own pericardium.

[0079] For example, a mitral valve prosthesis can be made from the patient's own pericardium. Alternatively, a mitral valve prosthesis can be made from a xenogeneic material (eg, animal tissue, such as an existing valve) over which a layer of the patient's own cultured cells is applied by tissue engineering.

[0080] Artificial valves are often fixed with glutaraldehyde, which is a known toxin and promotes regeneration. The mitral valve prosthesis of the present invention can be fixed by non-glutaraldehyde-based methods, such as dye-mediated photofixation. The mitral valve of the present invention can also be fixed by using alternative cross-linking agents such as epoxides, carbodiimides, diglycidyl ethers, rocephalin, genipin, diphenylphosphoryl azide, acyl azides and cyanamides, or by physical methods such as ultraviolet light and dehydration.

[0081] The mitral valve prosthesis or some parts of the prosthesis can be directly made with biological three-dimensional (3D) printing using biological materials. Alternatively, the mitral valve prosthesis or some parts of the prosthesis can be made using a template or mold constructed by 3D printing based on detailed dimensions obtained from 3D imaging performed preoperatively.

[0082] A method of implanting a mitral valve prosthesis is also provided. Prior to implantation, an echocardiogram study (or other imaging study) is obtained of the patient. From the imaging study, ventricular size and movement are measured. Detailed dimensions of the patient's mitral valve, leaflets, and chordae are also measured from the acquired images. In addition, a three-dimensional depiction of the valve to be replaced can be presented. Based on the measurements and three-dimensional modeling of the patient's native valve, a mitral valve prosthesis can be made that closely matches the patient's native mitral valve for correction of existing pathology.

[0083] Three-dimensional echocardiographic studies can be performed, for example, with a transesophageal echocardiographic (TEE) probe or a transthoracic echocardiographic (TTE) probe. Segments of the mitral valve can be modeled and measured in three and four dimensions using software such as eSieValves.TM. (Siemens Medical Solutions USA, Inc., Malvern, PA, USA). Relevant measurements can include the inner and outer diameters of the annulus, annular area, intertrigonal and intercomm distances, and lengths along various axes of the anterior and posterior leaflets.

[0084] Additionally or alternatively, three-dimensional studies of the mitral valve may be performed using computed tomography (CT) or magnetic resonance imaging (MRI). Figure 3 As shown, a 3D reconstruction of a pig heart was obtained using CT imaging (Siemens Healthcare, SOMATOM. RTM. Definition Flash, Erlangen, Germany), wherein the mitral valve region of the heart is visible on the right side of the image. Segmentation of the mitral valve region can be performed using image analysis software, and related measurements can be obtained.

[0085] A mitral valve prosthesis can be completely custom made for a patient, with each component (e.g., annulus, leaflets, cords, cap) manufactured to have dimensions that match those of the patient's native valve. Figure 4 As shown, a 3D printed mold of the mitral valve is created based on a 3D reconstruction of the imaged valve. Figure 4 The 3D printed valve shown in the figure is modeled during the diastolic, opening, and cardiac cycle. Prosthetic valves based on the 3D mold are also Figure 4 The mold can guide the cutting of the porcine pericardium into leaflets and chordae attachment sites. Alternatively, a prefabricated mitral valve or prefabricated mitral valve component that is closest in shape and size to the patient's native valve or native valve component can be selected for implantation.

[0086] Figure 5 An image of a prosthetic valve prototype sutured in an in vitro testing system is shown. The valve prototype is shown sutured to the implanted whole heart. A saline injection is injected into the left ventricle of the heart through a tube, where the aorta is clamped to contain the saline into the left ventricle and create pressure. For example, the injection pressure can be monitored on a pressure gauge connected to the injection line. The competence of the valve prototype (e.g., lack of regurgitation and valve leaflet prolapse) under physiological pressures can then be monitored. The competence of the valve can be measured or monitored at systolic pressure when the left ventricle contracts and the native membrane is closed.

[0087] FIG. 6A to FIG. 6B Schematic illustrations of the anterior and posterior leaflets of a prosthetic mitral valve, and the leaflets when coapted to each other, respectively, according to some embodiments of the present disclosure; Fig. 6A and Figure 6B , the prosthetic mitral valve can be a prosthetic mitral valve 600. According to some embodiments, the prosthetic mitral valve 600 may include two leaflets, such as an anterior mitral leaflet 602A and a posterior mitral leaflet 602P. Each of the posterior mitral leaflet 602P and the anterior mitral leaflet 602A can be designed and created as a monomer (single piece) before surgery to accommodate the patient's specific physiology and anatomy based on a cross-sectional image of the patient's heart. Measurements obtained from the patient's own heart can be used to determine the length, width, and height of each posterior mitral leaflet 602P and anterior mitral leaflet 602A, so that each leaflet is substantially the same as the patient's natural leaflet. Each leaflet can be shaped to include chordae tendineae (e.g., subgroup cord-like structures 604, 606, 608, 610) and additional material to form a ring portion (e.g., anterior ring portion 601A and posterior ring portion 601P). The length of the chordae tendineae can be determined by the surgeon to fit the patient, as further described below. The leaflets can be cut from a single piece of material using a knife or scissors and can be sewn together by the surgeon during a mitral valve replacement operation to form a mitral valve that resembles the patient's native mitral valve.

[0088] For example, the anterior leaflet (AL) height can be about 30 mm, the AL length can be about 45 mm, the posterior leaflet (PL) height can be about 15 mm, and the posterior leaflet length can be about 60 mm. Fig. 6A As shown in the figure, the medical community uses 630A as the height of the anterior mitral valve leaflet 602A, and 630P as the height of the posterior mitral valve leaflet 602P, and the length of each leaflet is referred to as the circumference portion of the leaflet, for example, 632A refers to the length of the anterior mitral valve leaflet 602A, and 632P refers to the length of the posterior mitral valve leaflet 602P.

[0089] According to some embodiments, separately cutting each of the anterior mitral leaflet 602A and the posterior mitral leaflet 602P from the same or different materials, and separately cutting each of the ring portions 601A and 601P, can facilitate personnel, such as a surgeon who is preparing a prosthetic mitral valve for implantation. Cutting the leaflets into two separate portions and the ring portion into two separate portions, and attaching the leaflets to the ring and further attaching a cord-like structure to each leaflet, reduces the preparation time and the time required to perform a surgical procedure to implant a prosthetic valve compared to when the leaflets and cord-like structures are cut as a single unit from a single piece of material. Cutting the leaflets and cord-like structures as a single unit and implanting a single-piece prosthesis is more complex and time-consuming than the methods disclosed herein due to the high precision required to cut each of the leaflets and cord-like structures while maintaining the connection between the leaflet portion and the cord-like structure portion intact.

[0090] In some embodiments, each of the ring portions 601A and 601P is created by rolling the posterior side of each leaflet so that the posterior side of each leaflet is folded or rolled onto itself (e.g., a rolled anterior portion 605A, and a rolled posterior portion 605P), toward the outside of the prosthetic mitral valve 600. Depending on the embodiment, the size of the posterior end of each leaflet can be increased by 5-10 mm of additional material, which can be used when rolling the posterior end of the leaflet onto itself to create the ring portion (such as the ring portion 601A in the anterior mitral leaflet and the ring portion 601P in the posterior mitral leaflet). Rolling or folding the ring (or each ring portion 601A and 601P) onto itself toward the outside of the prosthetic mitral valve 600 can help avoid the formation of clots inside the prosthetic mitral valve 600, and if clots occur, they will only appear on the outside of the prosthetic mitral valve 600 at the area where the ring or ring portion is folded or rolled, which poses a lower risk of damaging the effective operation of the prosthetic mitral valve 600. According to some additional embodiments, the ring (or each ring portion 601A and 601P) can be further strengthened by additional material strips (not shown) such as suitable biomedical fibers or polymers. Such strips can be supported by the material piece made of the prosthetic mitral valve 600 and are sized to fit each ring portion 601A, 601P. Preferably, such strips are 1-3 mm wide and 10-20 mm long. Such strips of material may be added to the prosthetic mitral valve 600, which are placed within each ring portion 601A, 601P as each ring portion 601A, 601P is rolled. These strips of material may be elastic and may be made of various compositions such as biocompatible rubber, rewound wire, or synthetic materials.

[0091] according to Figure 6B, the anterior mitral leaflet 602A may be semi-elliptical in shape or a planar convex shape, while the posterior mitral leaflet 602P may have a planar concave shape. In some embodiments, the prosthetic mitral valve 600 may include at least two groups of cable-like structures. In some embodiments, each of the at least two groups of cable-like structures is attached to a middle portion of a corresponding leaflet so as to simulate a natural mitral valve. For example, in some embodiments, the anterior mitral leaflet 602A may include at least one group of cable-like structures 603A, which may be connected to a middle portion of the anterior mitral leaflet 602A on one end of the anterior mitral leaflet 602A, which end is generally opposite to the end where the ring portion 601A is connected to the anterior mitral leaflet 602A. In some embodiments, at least one group of cable-like structures 603A may include at least two subsets of cable-like structures, for example, a subset of cable-like structures 604 and a subset of cable-like structures 606. According to some embodiments, these sub-group cable structures 604 and sub-group cable structures 606 are spaced apart so that a gap of about 3-5 mm is maintained between the two sub-group cable structures to achieve more effective engagement. The gap between the sub-group cable structures 604 and sub-group cable structures 606 also serves to create a more uniform distribution of tension on the leaflets and may reduce wear and tear. These sub-group cable structures 604 and 606 can be connected to different and separate caps for connecting the sub-group cable structures to the papillary muscles of the heart, such as with respect to FIG. 7A to FIG. 7B Detailed description.

[0092] In some embodiments, the posterior mitral leaflet 602P can include at least one set of cord-like structures 603P that can be connected to a middle portion of the posterior mitral leaflet 602P at one end of the posterior mitral leaflet 602P, which end is generally opposite to the end where the ring portion 601P is connected to the posterior mitral leaflet 602P.

[0093] In some embodiments, at least one group of cable-like structures 603P may include at least two subgroups of cable-like structures, for example, subgroup cable-like structures 608 and subgroup cable-like structures 610. These subgroup cable-like structures 608 and 610 are spaced apart so that a gap of about 5-8 mm is maintained between the two subgroup cable-like structures to achieve more effective engagement. These subgroup cable-like structures 608 and 610 may be connected to different and separate caps for connecting the subgroup cable-like structures to the papillary muscles of the heart, such as with regard to FIG. 7A to FIG. 7B Detailed description.

[0094] In some embodiments, the width of the cable structure 603A and / or the cable structure 603P can be between 1 mm and 2 mm, but other widths can be achieved. In some embodiments, the posterior mitral leaflet 602P can be connected to the ring portion 601P of the asymmetric ring on one side. Once the ring portion 601A is attached to the ring portion 601P, for example, via sutures, fasteners, etc., a complete asymmetric and flexible ring can be formed. In some embodiments, the sutures used to attach the ring portion 601A to the patient's valve annulus are composed of a radiopaque material.

[0095] According to some embodiments, the interchodal distance 634A in the anterior mitral leaflet 602A can be between 8-10 mm. In some embodiments, the interchodal distance 634A in the posterior mitral leaflet 602P can be between 10-15 mm. In some embodiments, the interchodal distance between the anterior leaflet and the posterior leaflet in the commissure region can be between 5-7 mm.

[0096] According to some embodiments, and as Figure 6B As shown, the anterior mitral leaflet 602A can be connected to the posterior mitral leaflet 602P, and the ring portion 601A can be connected to the ring portion 601P to construct the prosthetic mitral valve 600. Once the anterior mitral leaflet 602A is connected to the posterior mitral leaflet 602P, the orifice 620 created between the anterior mitral leaflet 602A and the posterior mitral leaflet 602P can enable blood to flow in one direction, namely from the left atrium to the left ventricle. Therefore, the orifice 620 created between the anterior mitral leaflet 602A and the posterior mitral leaflet 602P can be configured to prohibit backflow, namely from the left ventricle to the left atrium. The anterior mitral leaflet 602A, the posterior mitral leaflet 602P and the manner in which these leaflets are connected to each other with a certain degree of coaptation, as well as the ring portion 601A and the ring portion 601P can be configured to simulate the shape, size and therefore function of a natural human mitral valve. Specifically, ring portion 601A can be configured to simulate the anterior annulus, while ring portion 601P can be configured to simulate the posterior annulus of a native mitral valve. In some embodiments, each leaflet can include a shape extending approximately 1-5 mm between the ring portion and the cord structure to allow for better coaptation between the two leaflets and better attachment of the cord structure to each of the leaflets.

[0097] In some embodiments, the anterior mitral leaflet 602A can include at least two subsets of cable-like structures, for example, a subset of cable-like structures 604 and a subset of cable-like structures 606, which can be connected to the anterior mitral leaflet 602A at different ends of the anterior mitral leaflet 602A. In some embodiments, the posterior mitral leaflet 602P can include at least two subsets of cable-like structures, for example, a subset of cable-like structures 608 and a subset of cable-like structures 610, which can be connected to different ends of the posterior mitral leaflet 602P. As in the natural mitral valve, the cable-like structures should be connected to the papillary muscles of the heart. More specifically, in the natural human mitral valve, each subset of cable-like structures is attached to a different region of the papillary muscle. Therefore, the prosthetic prosthetic mitral valve 600 can include at least two subsets of cable-like structures for each leaflet, whereby each subset of cable-like structures will be attached to a different papillary muscle region so as to highly mimic the configuration, and therefore the operation, of the natural mitral valve. As will be described Figure 6C and FIG. 7A to FIG. 7B As shown, each subgroup of cable-like structures can be connected to the papillary muscle via a cap to ensure easy and sufficiently stable attachment between any subgroup of cable-like structures and the papillary muscle. The number of cable-like structures in each subgroup of cable-like structures, such as 604, 606, 608, and 610, can be different or the same. In some embodiments, each subgroup of cable-like structures can include at least two cable-like structures.

[0098] According to some embodiments, the two-piece valve of the present disclosure can ensure longer coaptation length between leaflets and allow for an exact carbon copy, one-to-one replication of a subject's own valve from a 3D ultrasound short-axis view.

[0099] Figure 6C is a schematic illustration of a top view of a mitral valve prosthesis looking down from the left atrium toward the left ventricle, according to an embodiment of the present disclosure. Figure 6CAs shown, the posterior mitral leaflet 602P can be attached to the anterior mitral leaflet 602A via an attachment line (e.g., suture 609). In some embodiments, the ring portion 601A can be attached to the ring portion 601P, such as suture 609, and can be rolled onto itself toward the outside of the prosthetic mitral valve 600. In some embodiments, the anterior mitral leaflet 602A can include two subsets of cable-like structures, such as subsets of cable-like structures 604 and subsets of cable-like structures 606, whereby each of these subsets of cable-like structures can be connected to a different papillary muscle 720 via a separate cap element 700. Accordingly, the posterior mitral leaflet 602P can include two subsets of cable-like structures 608 and 610, whereby each subset of cable-like structures can be connected to a different papillary muscle 720 via a separate cap element 700. For example, the subgroup cable structure 604 can be connected to the first papillary muscle 720 via the first cap member 700, and the subgroup cable structure 608 can also be connected to the same first papillary muscle via the same first cap member 700. Similarly, the subgroup cable structure 606 can be connected to the second papillary muscle 720 via the second cap member 700, and the subgroup cable structure 610 can also be connected to the same second papillary muscle 720 via the same second cap member 700.

[0100] according to Fig.6D In some embodiments, the posterior mitral leaflet 602P and the anterior mitral leaflet 602A can be cut from a single monomer and connected, for example, and sutured along suture line 609 to form a complete valve. According to some embodiments, the cord can be adjusted according to the individual optimal cord length of the recipient / patient based on a preoperative scan of the patient.

[0101] FIG. 7A to FIG. 7B1 is a schematic illustration of a cap for connecting a cable-like structure to a papillary muscle of a heart, and a heart valve prosthesis having two caps attached to the cable-like structure, respectively, according to an embodiment of the present disclosure. In some embodiments, the shape of the cap element 700 can be an arc shape when in the layout configuration. In some embodiments, the shape of the cap element 700 in the closed configuration can be similar to the shape of a tapered cone having a small opening 730 at its top end 702 and a wider opening at its bottom end 704, whereby the ends of the arc can be sutured to each other or one on the other using suture 706 to create a closed configuration. Suture 706 can be performed before placing the cap element 700 on top of the papillary muscle 720. In some embodiments, the measurement of the cap element 700 can be anywhere between 5 mm and 10 mm in diameter and 5-10 mm in height. According to some embodiments, the cap element 700 can be made of a single piece of material in the shape of a cap, while according to other embodiments, the cap element 700 can be made of two open leaflets or pieces of the same material to be sutured together and immediately sutured to the papillary muscle. For example, suturing can begin on one side of the two pieces of material of the cap member 700 and exit through a portion of the cap 700 so as to attach the cap member 700 to the papillary muscle, and so on, until the two portions of the cap member 700 are completely connected to each other and to the papillary muscle.

[0102] According to some embodiments, the cap element 700 of the prosthetic mitral valve 600 can be formed by wrapping the pericardium (e.g., from human, bovine or porcine) to a closed configuration. In some other configurations, the cap can be formed by a biomedical polymer. In some embodiments, the size of the cap element 700 can be 5 mm or more than 5 mm. In some embodiments, the chordae tendineae of the prosthetic mitral valve can be made of the same material as the leaflet and / or the cap. In some embodiments, the chordae tendineae can be chordae tendineae taken from the same source as the cap element 700, the anterior mitral leaflet 602A, and the posterior mitral leaflet 602P, for example, the same animal, for example, the same cow, for the added benefit of having the same cell structure and the same source as the cap element 700, the anterior mitral leaflet 602A, and the posterior mitral leaflet 602P.

[0103] Once the cap element 700 is placed on the papillary muscle 720, the cord-like structures, such as the subgroup cord-like structures 604, 608, can be connected to the cap element 700 using sutures 710, which can connect the cord-like structures, the cap element 700, and the papillary muscle 720 together. According to some embodiments, the cap opening 730 can enable a good fit between the cap element 700 and the papillary muscle 720, because the cap opening 730 allows the shape of the cap to be adjusted to the shape of the papillary muscle 720. In some embodiments, the cap element 700 can be attached to the subgroup cord-like structures 604 and 608 at one end, such as via sutures 710, while the cap element 700 can be attached to the papillary muscle of the heart from the other end (usually the opposite end of the cap element 700 next to the bottom end 704), such as via sutures 706. The cap member 700 may be connected to the papillary muscle 720 through the entire circumference of the bottom end 704 of the cap member 700 , but in some embodiments, the cap member 700 may be connected to the papillary muscle 720 via a specific portion along the circumference of the bottom end 704 of the cap member 700 .

[0104] According to some embodiments, the cable-like structures can be connected to each other so as to form a bundle of cable-like structures. The cable-like structures can be connected into a bundle at the ends of the cable-like structures, which are to be connected to the cap element 700 (e.g., the ends of the subset of cable-like structures 604 and 608 connected to the leaflet 602). According to some embodiments, connecting the cable-like structures, such as the subset of cable-like structures 604 and 608, to the papillary muscle 720 via the cap element 700 is easier than directly connecting the cable-like structures to the papillary muscle 720, because the latter requires a larger number of attachment processes. For example, if the attachment method is suturing, then suturing each of the cable-like structures to the papillary muscle 720 is more complicated and time-consuming than suturing the cable-like structures to the arranged cap element 700 and suturing the cap element 700, which is a single large piece, to the papillary muscle 720. Since patients receiving the prosthesis of the present disclosure are connected to a cardiopulmonary bypass, which is also commonly referred to as a heart-lung machine, it is preferred to perform mitral valve replacement more conveniently.

[0105] Although Fig. 7A Only two subgroups of cable structures 604 and two subgroups of cable structures 608 attached to the cap member 700 are shown, and it should be understood that additional cable structures can be connected to the cap member 700. The subgroups of cable structures 604, 608 may include one or more cable structures. In some embodiments, as Figure 6C As shown, four funicular structures 604 from the right scalloped portion of the anterior mitral leaflet 602A and four funicular structures 608 from the left scalloped portion of the posterior mitral leaflet 602P are connected to the cap member 700 .

[0106] In some embodiments, each of the subset of cable structures 604, 606, 608, and 610 can be connected to cap member 700 along the outside of cap member 700. In other embodiments, the cable structures of the prosthetic valve, or at least some of the cable structures, can be connected to cap member 700 via opening 730, which can be located in the middle of cap member 700. That is, the cable structures can pass through opening 730 and can be attached to the inside of cap member 700.

[0107] In some embodiments, the subset of funicular structures 604 , 606 , 608 , and 610 may first be connected to each other to form a bundle, and then may be connected to the cap element 700 .

[0108] like Figure 7B As shown, the prosthetic mitral valve 600 can include a flexible asymmetric ring 601 attached to two leaflets (e.g., anterior mitral leaflet 602A and posterior mitral leaflet 602P). In some embodiments, each of the two leaflets can have attached to it a set of cable structures, for example, subsets of cable structures 604 (not shown), 606 (not shown), 608, and 610. In some embodiments, each set of cable structures for each of the two leaflets can be attached to a single cap member 700, and each cap member 700 can connect the mitral valve prosthesis 600 to the papillary muscles 720 of the heart via connecting each subset of cable structures 610 to their respective cap members 700.

[0109] As described above, according to some embodiments, each subgroup of cable structures 604 (not shown), 606 (not shown), 608, and 610 can be made of the same material as the material used to make the anterior leaflet and the posterior leaflet. Each such cable structure, which can be considered an extension of the anterior mitral leaflet 602A and the posterior mitral leaflet 602P, can be referred to as a main cable structure. According to some embodiments, additional cable structures can be attached to the anterior mitral leaflet 602A and the posterior mitral leaflet 602P. Each of these secondary cable structures can be made of a different and separate piece of material from that used to construct the leaflets and the main cable knot. The secondary cable structure can be configured to connect the bottom side of each of the anterior mitral leaflet 602A and the posterior mitral leaflet 602P to a point along the main cable structure. The connection point of the secondary cable structure along the main cable structure can be the middle of the main cable structure, although other positions along the main cable structure can be implemented as a connection point to achieve better leaflet coaptation. The secondary cord-like structure can typically be sutured to the anterior mitral valve leaflet 602A or the posterior mitral valve leaflet 602P at one of its ends and at its other end, the secondary cord-like structure can be sutured to the main cord-like structure. When the secondary cord-like structure is attached to the anterior mitral valve leaflet 602A or the posterior mitral valve leaflet 602P, respectively, for example via sutures, damage to the outer surface of the anterior mitral valve leaflet 602A or the posterior mitral valve leaflet 602P should be avoided to prevent clots along the attachment line (e.g., sutures). For example, when suturing using a microscope, there is less likelihood of damaging the anterior mitral valve leaflet 602A and the posterior mitral valve leaflet 602P. The purpose of the secondary cord-like structure is to provide additional support for the prosthetic valve to resist pressure applied to the ventricular side of the prosthetic valve during systole.

[0110] FIG. 8A to FIG. 8B Schematic illustrations of possible positions of the secondary funicular structure relative to the posterior leaflet and cross-sections of the primary and secondary funicular structures when attached to the posterior leaflet, respectively, according to some embodiments of the present disclosure. Fig. 8AAs shown, the posterior mitral leaflet 602P can be rolled onto its posterior end to form a ring 601. In some embodiments, the posterior mitral leaflet 602P can be divided into several regions. Regions 812 and 814 can be regions to which the secondary cord-like structure 603 can be connected. However, there can be a region 816 along the posterior mitral leaflet 602P, which should be free, that is, the secondary cord-like structure should not be connected to the region 816. This is because region 816 is the region on which high pressure is applied once the posterior mitral leaflet 602P is connected to the heart as part of a prosthetic valve during ventricular contraction. In some embodiments, region 816 can include approximately 2-5 mm to the right of the midline 810 of the posterior mitral leaflet 602P, and approximately 2-5 mm to the left of the midline 810 of the posterior mitral leaflet 602P. In some embodiments, region 816 can include 3 mm to the right of midline 810 of the posterior mitral leaflet 602P, and 3 mm to the left. The secondary cord structure can be designed to provide additional support to the posterior mitral leaflet 602P as pressure gradients increase during ventricular systole.

[0111] In some embodiments, when in the layout configuration, the secondary cord-like structures 603 should not reach the ends of the regions 812 and 814 of the posterior mitral leaflet 602P. In some embodiments, no cord-like structures should be connected to the ends of the regions 812 and 814 that are close to the ring 601. For example, the cord-like structures can be positioned along any of the regions 812 and 814 along the entire posterior mitral leaflet 602P layout from about 20 degrees to 70 degrees relative to the midline 810 of the posterior mitral leaflet 602P. In addition to this, the regions of the posterior mitral leaflet 602P located between the midline 810 and about 15-20 degrees on either side of the midline 810 can remain free of secondary cord-like structures.

[0112] Figure 8B A cross section of the posterior mitral valve is schematically illustrated showing the primary and secondary cord structures when attached to the posterior mitral leaflet 602P. Figure 8B A subgroup of cable structures 608 is shown, which is made of the same material as the leaflet. The subgroup of cable structures 608 extending from the posterior mitral leaflet 602P on one of its ends is attached to the cap member 700 on its other end. In some embodiments, the subgroup of cable structures 608 can be connected to each other so as to form a bundle (not shown), which in turn can be connected to the outside of the cap member 700. The cap member 700 can in turn be connected to the papillary muscle 720.

[0113] According to some embodiments, the subset cord structures 608 can be connected to the secondary cord structures 603, whereby each of the secondary cord structures 603 can be connected to the posterior mitral leaflet 602P on one end (e.g., end 823) and to a contact point along the primary cord structure on the opposite end (e.g., end 825) of each of the secondary cord structures 603. According to some embodiments, the secondary cord structures 603 should be approximately 30-40% thicker and wider than the subset cord structures 608. Any number from one to four secondary cord structures can be used for each leaflet sector of the posterior mitral leaflet (602P), depending on the desired prosthesis.

[0114] FIG. 9A to FIG. 9B Schematic illustration of a prosthetic mitral valve with two leaflets attached in an alternative design featuring a curved (ellipsoid / droplet) configuration to enlarge the articulation surface and possible articulation surface configurations, respectively, according to some embodiments of the present disclosure. Fig.9A , the prosthetic valve 1100 can include two leaflets, such as anterior leaflet 1602A and posterior leaflet 1602P, whereby each of anterior leaflet 1602A and posterior leaflet 1602P can have a semicircular shape, and the two leaflets can together form a "yin and yang" shape. According to some embodiments, the leaflet shape can be designed in a semicircular manner along half of the length of each leaflet, so that the two leaflets create an "S" shaped seal when coapted.

[0115] This unique shape can achieve adequate engagement between the anterior leaflet 1602A and the posterior leaflet 1602P, specifically at region 1120. In some embodiments, there may be engagement or overlap between the anterior leaflet 1602A and the posterior leaflet 1602P along region 1120. Symmetrically, there may be a similar engagement or overlap area (not shown) between the posterior leaflet 1602P and the anterior leaflet 1602A. Similarly, for the prosthetic mitral valve 600 described in detail above, each leaflet can include a corresponding ring, such as ring 601A and ring 601P, which can be formed by winding each leaflet onto itself at one end of the material from which it is constructed.

[0116] according to Fig. 9B, there may be two coaptation configurations between the anterior leaflet 1602A and the posterior leaflet 1602P proximate the coaptation region. In some embodiments, as with respect to the prosthetic mitral valve 600, the prosthetic valve 1100 may include two types of cord-like structures; a primary cord-like structure and a secondary cord-like structure. According to some embodiments, the primary cord-like structure may be constructed as an extension to the anterior leaflet 1602A or the posterior leaflet 1602P, respectively. That is, the primary cord-like structure, such as the primary cord-like structure 1102A and 1102P, may be constructed of the same material as the corresponding leaflets, the anterior leaflet 1602A and the posterior leaflet 1602P. The primary cord-like structure 1102A and / or 1102P may extend from the middle portion of each leaflet at one end and may be connected to the cap at the other end. According to some embodiments, the secondary cord-like structure 1104P, may be attached only to the posterior leaflet 1602P. The secondary cord structure 1104P may be connected at one end to the middle portion of the posterior leaflet 1602P and at the other end to the middle portion of the main cord structure 1102P. According to some embodiments, the secondary cord structure 1104P may be added to better mimic the natural mitral valve including an additional shorter cord structure connected between the posterior leaflet and the posterior main cord structure. The addition of the secondary cord structure may allow the posterior leaflet to withstand the pressure applied to the posterior leaflet during the systolic phase and create proper coaptation (or closure) during the systolic phase of the heart cycle and further allow the leaflet to open during the diastolic phase.

[0117] For example, the posterior leaflet 1602P can have a secondary cord-like structure 1104P attached to the posterior edge of the posterior leaflet 1602P. The secondary cord-like structure 1104P can also be connected to a middle portion of the primary cord-like structure 1102P.

[0118] The secondary funicular structure 1104P may also be connected to the middle portion of the primary funicular structure 1102P.

[0119] Fig.10 is a schematic illustration of a measured copy of a patient's mitral valve according to some embodiments of the present disclosure. In some embodiments, measurements of the length, width, and height of the leaflet portions can be obtained via echocardiography, although other imaging methods can be used, such as cardiac CT or cardiac MRI, etc. Thus, the size and shape of valve 1200 can be substantially an exact copy of the patient's native or native mitral valve.

[0120] Fig.11 The formation of a two-leaflet prosthesis according to some embodiments of the present disclosure is schematically illustrated. In some embodiments, the basis of the valve, i.e., the leaflet portion, can be cut out from a single piece of material 1210 based on a cross-sectional image of the intended recipient's heart, such as Fig.12The size of the leaflet portion can be cut in a manner that replicates the prosthetic image at a scale such as 1:1, and a cut 1220 can be made along the middle of the leaflet portion in a crescent or semicircular form to provide an opening 1230, as well as definition of two leaflets (e.g., anterior leaflet 1202A and posterior leaflet 1202P), as shown. Fig.12 As shown in the picture.

[0121] Fig.12 Schematically illustrates an opening formed along a leaflet portion according to some embodiments of the present disclosure. In some embodiments, an opening 1230 can be formed (e.g., cut) in a single piece of material 1210, and two leaflets 1202A and 1202P can be formed on opposite sides of the opening 1230. Once the opening 1230 exists by cutting the single piece of material 1210, the two leaflets, such as the anterior leaflet 1202A and the posterior leaflet 1202P, can be in the form of flaps folded into the opening 1230, thereby further creating a unidirectional flow of blood through the opening 1230, i.e., from the left atrium to the left ventricle of the heart.

[0122] Fig.13 Schematically illustrated is an echocardiogram or MRI scan of a patient's left heart chamber or ventricle according to some embodiments of the present disclosure. In some embodiments, the patient's left ventricle 1500 can be imaged or scanned by echocardiography, CT or MRI or other imaging techniques. Such an image or scan of the left ventricle 1500 can provide the desired precise or substantially precise length of the patient's cord structure from the end of the papillary muscle 1520 to the valve leaflets 1502A and 1502P. This enables the manufacture of a customized prosthetic mitral valve according to the patient's anatomical and physiological requirements.

[0123] FIG. 14A to FIG. 14B Schematic representations of the left ventricle of a patient during diastole and during systole, respectively, according to some embodiments of the present disclosure. Fig. 14B As shown, during the diastolic phase, the left ventricle 1610 may include Fig.14A The illustrated left ventricle 1612 during the diastolic phase has a smaller annular diameter 1640 than the annular diameter 1650. When blood flows into the left ventricle during diastole, the left ventricle 1612 can fill with blood, and thus the annular diameter 1650 becomes larger. After the blood flows from the left ventricle to the patient's body blood system in order to reach the organs, the blood leaves the left ventricle 1610 during the systolic phase. Therefore, the volume of the left ventricle 1610 during systole is smaller than that of the left ventricle 1612 during diastole, which makes the annular diameter 1640 during the systolic phase smaller than the annular diameter 1650 during diastole.

[0124] Since the annulus and leaflets 1502A and 1502P need to be flexible as they repeatedly change their diameter and size during repetitive phases of heart function (i.e., systole and diastole), it should be clear that the annulus and leaflets are desirably made of the same elastic material as the tissue that the native mitral valve is made of. Thus, a prosthesis without a stent, without a metal ring, and without a rigid material is disclosed, and the materials selected for making the leaflets 1502A and 1502P and the annulus require a certain amount of compliance and elasticity.

[0125] FIG. 15A to FIG. 15B Schematic illustrations of extensions attached to the anterior leaflet and the posterior leaflet, respectively, according to some embodiments of the present disclosure. Fig.15A As shown, the anterior leaflet 1202A may include an extension 1703 that includes additional material to extend the size of the anterior leaflet 1202A. The extension 1703 is sized to be approximately 1-5 mm in length and is substantially sized to form the incision (e.g., Fig.11 In some embodiments, the extension 1703 is sutured at one end to the edge of the anterior leaflet 1202A (see Fig.11 The incision 1220) includes a cable-like structure 1704 at the other end, which can be similar to Fig. 6A The subgroup cable-like structures 604, 606.

[0126] like Fig. 15B As shown, the posterior leaflet 1202P may include an extension 1709 that includes additional material to extend the size of the posterior leaflet 1202P. The extension 1709 is sized to be approximately 1-5 mm in length and is substantially sized to form the incision (e.g., Fig.11 In some embodiments, the extension 1709 is sutured at one end to the edge of the posterior leaflet 1202P (see Fig.11 The incision 1220) includes a cable-like structure 1708 at the other end, which can be similar to Fig. 6A The cable-like structures 608 and 610 are provided.

[0127] like Fig. 15B As shown, the posterior leaflet 1202P has an extension 1709 attached to one end and a cable-like structure 1708 attached to the other end. The cable-like structure 1708 is connected to the extension 109 at one end and to a cap 1870 at the other end, which can be similar in structure to the combined Fig. 7AThe anterior leaflet 1202A has an extension 1703 attached at one end and a cable-like structure 1704 attached at the other end. The cable-like structure 1704 is connected to the extension 1703 at one end and to the cap 1870 at the other end, which can be similar in structure to the combined Fig. 7A Description of the cap.

[0128] Each of the cable structures 1704 and 1708 may include several cable structures, such as four main cable structures, which are also described herein as main cable structures, although any other number of cable structures may be implemented according to the specific requirements of each patient. In some embodiments, the cable structures may also include secondary cable structures (not shown) as described herein above.

[0129] FIG. 16A to FIG. 16B is a schematic illustration of a side view of a mitral valve prosthesis having extensions and attached cord structures during diastole and systole, respectively, according to some embodiments of the present disclosure. Fig.16A , a side view of a mitral valve prosthesis showing the profile of the mitral valve prosthesis when the heart is in diastole, and reference Fig. 16B , showing a side view of a mitral valve prosthesis when the heart is in diastole. The anterior leaflet 1202A and the posterior leaflet 1202P are positioned at a distance from each other to allow blood to flow through an orifice between the anterior leaflet 1202A and the posterior leaflet 1202P into the left ventricle. Extensions 1703, 1709 enable the valve prosthesis to have an enhanced coaptation profile. Each of the anterior leaflet 1202A and the posterior leaflet 1202P can have an extension 1703, 1709 attached to provide additional material to the anterior leaflet and the posterior leaflet to provide the necessary coaptation during diastole to prevent blood from flowing back into the atrium and to provide support to the left ventricle during systole.

[0130] In some embodiments, extension 1703 and extension 1709 are prepared in different sizes (eg, length, width, and shape). In some embodiments, before being attached to cap 1870, cord-like structures 1704, 1708 can be tied and fixed together by suturing.

[0131] Extensions 1703 and 1709 are each configured to carry a corresponding cord-like structure (1704, 1708) that is similar to the cord-like structure of a natural heart valve and that should be inserted into a heart chamber and attached to the heart wall muscle or papillary muscle. For example, extension 1703 may carry a cord-like structure or cord-like structure group 1704, while extension 1709 may carry a cord-like structure or cord-like structure group 1708. Each of the at least two cord-like structures may be connected at the other end (opposite to the end connected to each of the extensions) to a cap 1870 that is configured to attach the valve to the papillary muscle.

[0132] In some embodiments, during the diastolic phase, such as Fig.16A As illustrated, the anterior leaflet 1202A and the posterior leaflet 1202P and the corresponding extensions 1703 and 1709 are positioned at a distance from each other to enable blood to flow in one direction from the left ventricle toward the left atrium.

[0133] In some embodiments, during the contraction phase, as Fig. 16B As shown, the anterior leaflet 1202A and the posterior leaflet 1202P and the corresponding extensions 1703 and 1709 are positioned close to each other to prevent the backflow or leakage of blood in the opposite direction, that is, from the left ventricle to the left atrium. According to some embodiments, the extensions, such as extensions 1703 and 1709, provide the necessary coaptation or closure of the valve to inhibit leakage or backflow of blood from the left ventricle to the left atrium.

[0134] According to some embodiments, the extensions may be cut to fit the edges of the leaflets and measure no less than 5 mm in varying widths to ensure adequate coaptation. The extensions will be attached to the leaflets by suturing, gluing, stapling or otherwise attaching to the edges of the leaflets.

[0135] According to some embodiments, cable structures, such as cable structures 1704 and 1708, may be individually attached, such as sutured to the heart chamber wall or papillary muscles, or may be bundled together, such as in pairs, groups of four, etc., depending on the design determined to be optimal for a particular patient.

[0136] According to some embodiments, the cords may be asymmetric. That is, the size of the cords may vary, since the left ventricle has two papillary muscles, and the cords extending from various points of the leaflet extensions may include different lengths and distances from the top edges of those muscles. Thus, each cord or bundle of cords may have a single different length compared to the others. This will ensure perfect closure and adequate coaptation length of the prosthetic valve.

[0137] In some embodiments, cord-like structures, such as cord-like structures 1704 and 1708, each extending from a leaflet extension, such as extensions 1703 and 1709, can be distributed along the edges of the anterior leaflet and posterior leaflet extensions to distribute tension along the edges of these leaflets when the valve moves in the body, thereby reducing wear and tear on the prosthetic valve.

[0138] Fig.17Schematic illustration of an asymmetric flexible ring attached to the periphery of a valve prosthesis to simulate a native annulus, according to some embodiments of the present invention. According to some embodiments, flexible ring 1901 can be formed by winding a piece of elongated material onto itself and closing it into an annular shape, or by winding a piece of material with a hole in the middle onto itself toward the outside of the material. In some embodiments, the wound flexible ring 1901 can be attached to the periphery of valve 1200 to allow surgical attachment, such as suturing to the patient's annulus, to allow for better stiffness of the annulus, and to provide better elasticity during the heart cycle that changes between contraction and relaxation when an elastic material is used. The wound ring 1901 can fit the periphery of the initially cut valve 1200 ( Fig.10 ). In some embodiments, the suture material used for surgical attachment to form the ring shape is a radiopaque material. In some embodiments, the suture material used for surgical attachment to attach the mitral valve prosthesis to the annulus of the patient is a radiopaque material.

[0139] According to some embodiments, the flexible ring 1901 can be made of an elastic material containing variable elasticity to allow variable expansion and contraction of the prosthetic valve during the diastolic and systolic heart cycles, respectively. In some embodiments, the elasticity of the flexible ring 1901 can be derived from continuous studies of the movement of the patient's native valve annulus based on 3D echocardiographic studies.

[0140] In some embodiments, the flexible ring 1901 can be exposed to the blood environment inside the heart, or can be rolled into a sandwich structure engulfing an elastic material, and the flexible ring 1901 can be made of the same material as the leaflets surrounding it.

[0141] like Fig.17 As shown, valve 1200 may include cord structures 1704 and 1706 that may be attached to anterior leaflet 1202A (via or without extensions), and cord structures 1708 and 1710 that may be attached to posterior leaflet 1202P (via or without extensions). FIG. 16A to FIG. 16B As illustrated, the cord-like structure may be attached to at least two caps configured to attach valve 1200 to papillary muscles of the heart, thereby enabling mitral prosthetic valve 1200 to be properly attached to the patient's left ventricle based on the anatomical and physiological requirements of the particular patient.

[0142] 18A to 18E Schematic illustration of an elastic material to be inserted into a rolled valve annulus before and after the ring is rolled thereon, respectively, according to some embodiments of the present disclosure. Figures 18A to 18CAs illustrated, the ring 2201 can include an added elastic material 2205 that can be inserted into the ring 2201 so that the ring 2201 is wrapped over the elastic material 2205 and the elastic material 2205 is "sandwiched" within the ring 2201. The addition of the elastic material 2205 within the ring 2201 serves to provide additional elasticity to the ring 2201, which can help to better mimic the elastic characteristics of the natural mitral valve. In some embodiments, the elastic material 2205 can be rubber or any other biocompatible synthetic material. In some embodiments, the shape of the elastic material 2205 is similar to the shape of the ring 2201 into which it is inserted so that the elastic material 2205 can be easily inserted into the ring 2201.

[0143] According to some embodiments, and as Fig.18B As shown, the ring 2201 (which may be made of the same material as the leaflets, or may be made of an alternative material that is an extension of the outer edge of the leaflets) can be wrapped over the elastic material 2205 toward the inside of the synthetic valve, such as toward the cutout 2220, which can be made in a crescent or semicircular form along the middle of the leaflet portion to provide an opening between the two leaflets (e.g., the anterior leaflet 2202A and the posterior leaflet 2202P) defined by the cutout 2220. The cutout 2220 is actually the true mitral valve prosthesis orifice through which blood flows from the left atrium to the left ventricle. Thus, the outer edge of the mitral valve prosthesis can include the ring 2201, and connected to the ring 2201 are the major surfaces of the leaflets (e.g., the anterior leaflet 2202A and the posterior leaflet 2202P), which in turn are connected to the papillary muscles 2270 via, for example, the cord-like structure 2204, through the cap.

[0144] According to some embodiments, Fig. 18C , Fig.18DAs shown, the elastic material 2205 is made partially or entirely of a radiopaque marker filament 2240. According to some embodiments, a radiopaque marker filament 2240 is added and placed inside the ring 2201 along the elastic material 2205. The radiopaque marker filament 2240 can be placed inside the elastic material 2205 or as a separate component placed along the side of the elastic material 2205. The radiopaque marker filament can be sutured into position inside the ring 2201 using a polypropylene suture material 2242 so that the ring 2201 is wrapped over the radiopaque marker filament and the radiopaque marker filament is "sandwiched" inside the ring 2201. In some embodiments, the radiopaque marker filament and the elastic material 2205 are "sandwiched" together. In some other embodiments, the radiopaque marker filament 2240 is sutured to the edge of the ring 2201 without wrapping around the ring 2201. The radiopaque marker filament can be sutured in place using sutures, either circular sutures 2244 or horizontal sutures 2246. The radiopaque marker filament 2240 may preferably be made of platinum, platinum-iridium, gold, nitinol, tungsten or palladium. The use of the radiopaque marker filament 2240 as described herein above may be used for any future necessary intervention, e.g., a valve-in-valve for a transcatheter prosthetic implant. The presence of a radiopaque marker in the ring 2201 or attached to the ring 2201 will provide guidance to the physician and identification of the mitral annulus due to its visibility under conventional imaging scans (e.g., CT, MRI, X-ray).

[0145] according to Fig.18E In some of the illustrated embodiments, during the native mitral valve resection, one or more small pieces of native mitral valve leaflets 2250, 2252 are harvested from the patient preoperatively. Depending on the pathology of the patient's native mitral valve, the surgeon identifies a healthy portion of the patient's native mitral valve and resects it along with the attached portions of the healthy chordae tendineae 2254, 2256. The one or more healthy resected native mitral valve pieces of the native mitral valve leaflet portions 2250, 2252 and their attached chordae tendineae 2254, 2256 are then retained and attached, for example, to the posterior leaflet 2202 of the mitral valve prosthesis. The one or more healthy resected native mitral valve pieces of the native mitral valve leaflet portions 2250, 2252 can be connected to the posterior leaflet by suturing or gluing. The chordae tendineae 2254, 2256 are also attached to the patient's papillary muscles 2270, as described herein. The resected natural mitral valve leaflets and resected chordae tendineae will depend on the patient's own condition, so that the patient has healthier tissue that will benefit from the autologous materials used in the construction of their own mitral valve prosthesis. Such additional resected natural mitral valve leaflets and chordae tendineae will serve as a secondary cord-like structure for support of the mitral valve prosthesis described herein, and can reduce the shear stress on the prosthesis, thereby making the durability and life of the prosthesis longer.

[0146] Fig.19is a schematic flow chart illustrating a method for manufacturing a mitral valve prosthesis according to some embodiments of the present disclosure. According to some embodiments, a method 2000 for manufacturing a mitral valve prosthesis customized for a patient may include an operation 2002, which may include measuring the size and shape of the patient's mitral valve via an imaging method. The imaging method for measuring the shape and size of the mitral valve of a particular patient may be an echocardiogram, a cardiac CT, a cardiac MRI, and any other imaging method. The method 2000 may also include an operation 2004 of cutting a replica of the patient's mitral valve from a single piece of material at a 1:1 ratio. In some embodiments, the method 2000 may include an operation 2006 of cutting an incision along the single piece of material to create an orifice for blood flow and two leaflets, one on each side of the orifice. The method 2000 may include an operation 2008 of measuring the length of the desired cord-like structure via an imaging method, which may be similar to the imaging method for measuring the shape and size of the mitral valve as in operation 2002.

[0147] In some embodiments, method 2000 may also include an operation 2010 of attaching the cable-like structure to one of two caps configured to attach the cable-like structure to a papillary muscle of the heart.

[0148] In some embodiments, method 2000 can include operation 2012, which can include attaching a flexible ring to the leaflets, thereby creating an entire mitral valve prosthesis that simulates a native mitral valve according to a particular patient.

[0149] In some embodiments, method 2000 may also include an optional operation that may include attaching extensions to each of the two leaflets to carry the cord-like structures as measured in operation 2008. These extensions may help provide proper coaptation and closure during systole of the heart cycle.

[0150] According to some embodiments, any disclosed anterior leaflet and posterior leaflet, any ring, any cord-like structure (and any subgroup cord-like structure), any cap and / or any combination thereof can be made by natural materials. Allograft materials and / or composite materials, including various combinations of allografts, xenografts and / or autologous transplant materials, can also be used to make flexible rings, leaflets, cord-like structures and caps. The materials forming the valve ring and leaflet can include but are not limited to human, bovine or porcine pericardium, decellularized biological materials, woven biodegradable polymers incorporating cells, and extracellular materials. Biodegradable natural polymers can include but are not limited to fibrin, collagen, chitosan, gelatin, hyaluronic acid and similar materials. Biodegradable synthetic polymer scaffolds that can be infiltrated with cells and extracellular matrix materials can include but are not limited to poly (L-lactide), polyethylene, poly (lactic acid-co-glycolic acid), poly (caprolactone), polycyclic esters, poly (dioxysiloxane), poly (anhydride), poly (trimethylene carbonate), polyphosphazene and similar materials. The flexible ring can be further customized to provide individualized flexibility or rigidity for the patient. In addition, some components of the mitral valve prosthesis, including the cord structure, can be molded intraoperatively from the patient's own pericardium.

[0151] According to some embodiments, any disclosed asymmetric flexible ring can be formed by rolling or folding the edges of (one or more) leaflets onto themselves, they can include a front ring portion and a rear ring portion, or can be manufactured as a single unit. In other embodiments, the flexible ring can also include at least two strands or layers of material, for example, human, bovine or porcine pericardium, or any of the materials listed above, whereby the at least two strands or layers can be coiled, twisted, braided or looped one around the other. A ring with a coiled roll structure can contain greater strength than a ring formed by simply rolling the edges of the leaflets onto themselves, but the coiled ring should maintain its elasticity.

[0152] According to some embodiments, the ring includes two strands or layers of material folded together to provide elasticity, with a third layer added to provide structural stability. In some embodiments, the ring may include two layers supported by bovine pericardium, while the third strand or layer may be made of glycine or proline to provide strength to the ring.

[0153] In some embodiments, at least two layers or strands may be attached, such as sutured, to each other.In some embodiments, a third layer may be attached, such as sutured, to at least two layers of the ring.

[0154] According to some embodiments, the components of the prosthetic mitral valve can be attached or connected to each other via a plurality of connection methods. For example, the components of the prosthetic mitral valve can be connected to each other via sutures, staples, glue or any other attachment means.

[0155] In some embodiments, the suture or stitches can be made of non-biodegradable synthetic materials, such as nylon (ethilon), prolene (polypropylene), Novalfil, polyester, etc. In some embodiments, the suture or stitches can be made of non-biodegradable natural materials, such as surgical silk or surgical cotton.

[0156] In some embodiments, the staplers can be made from a biocompatible material, such as stainless steel or titanium.

[0157] In some embodiments, the glue can be made of a biocompatible material, such as aldehyde-based glue, fibrin adhesive, collagen-based adhesive, polyethylene glycol polymer (hydrogel), or acrylic resin-based adhesive.

[0158] According to some embodiments, any of the leaflets, any annulus, any cord-like structures (and any subset of cord-like structures), and / or any combination thereof can be customized to the patient based on ultrasound imaging of the patient's native mitral valve and surrounding anatomy. A customized mitral valve can also be made based on data obtained through other imaging modalities that provide three-dimensional information, including cardiac CT and cardiac MRI. In this way, a mitral valve prosthesis of the present disclosure can be selected or designed to match the patient's specific anatomy, thereby increasing the likelihood that the patient's surrounding tissue, such as the myocardium surrounding the prosthesis, will be highly accepting of the prosthesis.

[0159] In preparation for implantation in the patient, the patient's heart is captured, as is common for mitral valve surgery. During implantation, the flexible ring of the prosthesis is secured to the native valve annulus by sutures, and the papillary cap is sutured to the native papillary muscles. For example, two sutures may be applied at the tip of each of the native papillary muscles, securing the cap to the muscle. The clinician ensures that the valve will open and close completely by filling the ventricular cavity with saline and checking the movement and competence of the replacement valve as it closes under applied pressure. After implantation, the valve is examined with a transesophageal echocardiogram (TEE) after the heart has closed and resumed beating.

[0160] If desired, anticoagulant medications may be administered to the subject after implantation. Low doses of anticoagulant medications or no anticoagulant medications are contemplated for most patients given the natural shape and natural materials used to construct the mitral valve prosthesis of the present invention.

[0161] Currently available biological and mechanical prostheses carry several disadvantages: they contain bulky foreign matter, require powerful anticoagulant medications, have a short service life requiring the patient to undergo follow-up surgery when replacement is necessary, and do not help the heart recover effectively from transplantation. The present invention provides several advantages over the above biological and mechanical prostheses. Having a design that more closely matches the patient's natural mitral valve and being manufactured from natural materials, the mitral valve prosthesis is expected to require a shorter recovery time for the patient, provide a longer service life, and reduce or eliminate the need for anticoagulant medications.

[0162] The teachings of all patents, published applications, and references cited herein are incorporated by reference in their entirety.

[0163] While the invention has been particularly shown and described with reference to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as encompassed by the following claims.

Claims

1. A mitral valve prosthesis to be implanted in a heart, comprising: an asymmetric ring sized to mimic the patient's native mitral valve annulus; The asymmetric ring is constructed of a flexible material that is rolled onto itself toward the outside of the valve; an anterior flexible leaflet and a posterior flexible leaflet, the anterior leaflet and the posterior leaflet suspended from the asymmetric ring and configured to engage one another; each of the anterior leaflet and the posterior leaflet shapes are configured to mimic the shape of a native mitral valve, wherein the anterior leaflet and the posterior leaflet create an orifice through which blood flows in one direction; and at least two sets of cord-like structures, each set of cord-like structures attached at a first end to the anterior leaflet or the posterior leaflet and attached at a second end to a cap, the cap being configured to attach to a papillary muscle of the heart at another end of the cap; The asymmetric ring also includes at least two strands constructed in a coiled coil structure; the asymmetric ring includes two layers of material folded together to provide elasticity, and a third layer to provide structural stability; the asymmetric ring includes two layers of bovine pericardium; and a third layer of glycine or proline to provide strength.

2. The mitral valve prosthesis according to claim 1 further includes an engagement surface that is continuous with each of the anterior leaflet and the posterior leaflet and attached to each set of cord-like structures; the engagement surface is configured to enhance the sealing of the mitral valve prosthesis.

3. The mitral valve prosthesis of claim 1, wherein the layers are connected together via sutures, staples, glue, or any combination thereof.

4. The mitral valve prosthesis of claim 1, wherein the asymmetric ring, the anterior flexible leaflet and the posterior flexible leaflet, the at least two cord-like structures, the cap, or any combination thereof are made of bovine pericardium.

5. The mitral valve prosthesis of claim 1, wherein the leaflet shape is extended by 1-5 mm to allow for better coaptation and cord attachment.

6. The mitral valve prosthesis of claim 1 , wherein the leaflet shape is designed in a semicircular manner along half of the length of the anterior flexible leaflet and the posterior flexible leaflet such that the two leaflets create an “S” shaped seal when engaged.

7. The mitral valve prosthesis according to claim 1 further includes at least one secondary cord-like structure; and wherein the at least one secondary cord-like structure is attached to the middle portion of the posterior leaflet at one end and to the middle portion of the main cord-like structure at the other end.

8. The mitral valve prosthesis of claim 1, wherein the at least two sets of cord-like structures are attached to an opening of the cap, the opening being located in the middle of the cap.

9. The mitral valve prosthesis of claim 1, wherein each of the at least two groups of cord-like structures is attached to a middle portion of the anterior leaflet or the posterior leaflet to simulate a naturally occurring mitral valve.

10. The mitral valve prosthesis of claim 1, wherein the anterior leaflet or the posterior leaflet is made of a single unit connected to the asymmetric ring and attached to at least two sets of cord structures.

11. The mitral valve prosthesis according to claim 1 further includes an extension portion, which is connected to the anterior flexible leaflet at one end and to at least two groups of cord-like structures at the other end, and is configured to allow engagement between the anterior flexible leaflet and the posterior flexible leaflet.

12. The mitral valve prosthesis of claim 1, wherein at least a portion of the at least two sets of cord-like structures comprise the patient's own native mitral valve chordae tendineae.

13. The mitral valve prosthesis of claim 1, wherein at least a portion of the at least two sets of cord-like structures include the patient's own native mitral valve chordae tendineae and at least a portion of the patient's own native leaflets.

14. The mitral valve prosthesis of claim 1, wherein the asymmetric ring further comprises a radiopaque marker filament inserted within the coiled flexible material.

15. The mitral valve prosthesis of claim 1, wherein the mitral valve prosthesis further comprises a suture made of a radiopaque suture material formed through the ring.

16. A mitral valve prosthesis to be implanted in a heart, comprising: an asymmetric ring sized to mimic a patient's native mitral valve annulus; The asymmetric ring is constructed of a flexible material that wraps onto itself toward the outside of the mitral valve; two leaflets suspended from the asymmetric ring, the leaflets being constructed on opposite sides along a cut made from a material from which the asymmetric ring is constructed, wherein the cut creates an orifice through which blood flows in one direction; at least two sets of cord-like structures, each set of cord-like structures attached at a first end to one of the two leaflets and attached at a second end to the bundle; and a cap attached to the at least two sets of cord-like structures at one end of the cap and configured to be sutured to a papillary muscle of the heart at another end of the cap; The asymmetric ring also includes at least two strands constructed in a coiled coil structure; the asymmetric ring includes two layers of material folded together to provide elasticity, and a third layer to provide structural stability; the asymmetric ring includes two layers of bovine pericardium; and a third layer of glycine or proline to provide strength.

17. The mitral valve prosthesis of claim 16, wherein each set of cord-like structures is attached to one of the two leaflets via an extension configured to allow coaptation between the two leaflets.

18. The mitral valve prosthesis of claim 17, wherein each set of cord-like structures is composed in part of the patient's own natural mitral valve cord-like structures.

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