CN116407346A - Prosthetic valve fixation device and valve replacement device comprising same - Google Patents

Abstract

The present application relates to a prosthetic valve fixation device for fixing a prosthetic valve to a leaflet of a native valve, comprising: an inner stent having an open proximal end, an open distal end, and a tubular sidewall extending along a longitudinal axis of the prosthetic valve fixation device between the open proximal end and the open distal end; and an outer bracket having a three-dimensional annular shape extending in an axial direction and configured to be sleeved on a radially outer side of the inner bracket; wherein the inner and outer stents are configured to clamp each leaflet of the native valve between the inner and outer stents to secure the prosthetic valve securing device to the leaflets of the native valve, and wherein the outer stent is fixedly connected to the inner stent in an axial direction along a longitudinal axis. The present application also relates to a valve replacement device comprising the above-described prosthetic valve fixation device.

Description

Prosthetic valve fixation device and valve replacement device comprising same

Technical Field

One aspect of the present application relates generally to a prosthetic valve fixation device and, in particular, to a device for securing a prosthetic valve to a native valve. Another aspect of the present application relates to a valve replacement device comprising the above-described prosthetic valve fixation device.

Background

Valve disease is a common cardiovascular disease including malformations, valve stenosis, calcification, insufficiency, regurgitation, etc. caused by congenital or acquired diseases and aging. These valve diseases alter the normal flow mechanics of blood and in turn cause a series of symptoms such as palpitations, shortness of breath, tiredness, oedema, angina, fainting, etc. after an activity. In particular, aortic valve calcification, stenosis, insufficiency and regurgitation are common valve diseases.

For patients with aortic valve calcification and stenosis, the recently adopted transsheath aortic valve implantation (Transcatheter Aortic Valve Implantation, TAVI) is a common treatment. In TAVI, a balloon is delivered to the aortic valve region via, for example, the femoral artery by an interventional delivery instrument (such as a sheath) and radially expanded to squeeze the native valve open to expose the annulus. Then, a prosthetic valve (such as made of porcine pericardium) secured to the prosthetic valve fixture is retractably received in the interventional delivery instrument and delivered to the aortic valve region via, for example, the femoral artery. After reaching the aortic valve region, the balloon that is sleeved inside the prosthetic valve fixation device is again radially expanded to force the prosthetic valve fixation device to radially expand so as to radially support within the annulus of the aortic valve. After removal of the balloon and interventional delivery device, the implanted prosthetic valve functions in place of the native valve, acting to open and close as the left ventricle contracts and expands. The prosthetic valve fixation device is more firmly secured within such valve rings because the valve ring of the native aortic valve of the patient with calcification and stenosis can provide a strong reaction force to the radial support of the prosthetic valve fixation device.

However, for patients with simple aortic valve regurgitation (no stenosis or calcification of the aortic valve), the annulus tissue of the native aortic valve is typically soft and does not provide sufficient radial support. In this case, it is often difficult to fix the prosthetic valve at the native annulus with radial support forces using the prosthetic valve fixation devices described above. In addition, patients with aortic valve bileaflet deformity, accompanied by simple regurgitation, without stenosis and calcification, are also difficult to treat with the above prosthetic valve fixation devices, as the annulus tissue is generally soft. It can be seen that there is a need in the art of valve replacement devices for prosthetic valve fixation devices with improved fixation means and valve replacement devices incorporating the same to address the problem of fixation of prosthetic valves in the treatment of patients with non-stenosed and non-calcified valves (such as aortic valve, simple reflux disease of pulmonary valve, etc.).

Disclosure of Invention

The above-described problems and other problems discussed below are at least partially solved by a prosthetic valve return fixation device and a valve replacement device comprising the same according to embodiments of the present application. One aspect of the present application relates to a prosthetic valve fixation device for securing a prosthetic valve to a leaflet of a native valve. The prosthetic valve fixation device may include an inner stent and an outer stent. The inner stent may have an open proximal end, an open distal end, and a tubular sidewall extending along a longitudinal axis of the prosthetic valve fixation device between the open proximal end and the open distal end. The outer stent may have a three-dimensional annular shape extending in an axial direction and may be configured to fit radially outward of the inner stent. The inner and outer stents may be configured to clamp each leaflet of the native valve between the inner and outer stents to secure the prosthetic valve fixation device to the leaflets of the native valve. The outer stent may be connected to the inner stent in an axial direction along the longitudinal axis. By clamping the leaflets of the native valve, the prosthetic valve fixation device according to the present application can position the carried prosthetic valve by means of the leaflets of the native valve, without relying on radial support forces to rest on the inner circumference of the annulus, thus being suitable for non-calcified, non-stenosed valve disease patients. The three-dimensional, generally annular shape of the outer stent may "nest" the leaflets of the native valve from the outside, while the inner stent may push the leaflets toward the outer stent from the inside. In addition, the outer stent is fixedly connected to the inner stent in an axial direction along the longitudinal axis, eliminating axial relative movement of the inner and outer stents during implantation, thereby simplifying the complexity of the interventional delivery instrument and implantation procedure and reducing the risk of operational failure.

In some embodiments, the outer stent is configured to at least partially self-expand to return to an original radial dimension in the expanded state when the radial compressive force is removed from the outer stent after being radially compressed from the expanded state to a contracted radial dimension in the compressed state under the force of the radial compressive force. By virtue of the self-expanding nature of the outer stent, the outer stent of a prosthetic valve fixation device according to the present application may at least partially self-recover in diameter when extended distally from an interventional delivery instrument during implantation. Thus, the circumferential angle of the prosthetic valve fixation device need only be adjusted prior to capturing the leaflets of the native valve, rather than having to use an inflation device such as a balloon to restore or enlarge the diameter of the outer stent.

In some embodiments, the outer diameter of the outer stent in the deployed state is no greater than the inner diameter of the annulus of the native valve, preferably 15mm to 30mm. The prosthetic valve fixation device according to the present application is supported on the inner circumference of the annulus independent of radial support forces, thus avoiding any additional damage to the annulus while ensuring that the prosthetic valve fixation device does not shift.

In some embodiments, the outer stent is made of a shape memory material or a superelastic material. In some embodiments, the shape memory material is a shape memory nickel titanium alloy. Shape memory nitinol, such as nitinol, has good shape memory properties such that the outer stent is able to recover to a greater extent by itself to the original diameter of the deployed state, such as to 90% or more, preferably 95% or more, more preferably 99% or more, and most preferably fully to the original diameter. In addition, the material also has excellent biocompatibility to reduce rejection reactions.

In some embodiments, the three-dimensional annular shape of the outer stent includes at least two distal raised portions, each of the at least two distal raised portions for clamping a respective leaflet of the native valve between the respective distal raised portion and the inner stent. During the implantation procedure, the outer stent laterally encases the leaflets of the native valve in a distal direction from the proximal side to the distal side. The distal convex portion faces the leaflet in a distal direction to capture it into the space between the outer stent and the inner stent in a contracted state.

In some embodiments, each of the at least two distal raised portions has a "U" shape. The "U" shape has rounded edges to avoid damaging or irritating the leaflets of the native valve.

In some embodiments, each pair of adjacent distal raised portions of the at least two distal raised portions are joined together at a proximal connecting portion to connect them to form the complete three-dimensional annular shape of the outer stent.

In some embodiments, the proximal connecting portion is fixedly connected to the inner stent, such that the outer stent is fixedly connected to the inner stent as a whole, in particular in an axial direction along the longitudinal axis.

In some embodiments, the outer stent may be connected to the inner stent by wire stitching or tying, welding or fusion.

In some embodiments, the inner stent has a compressible lattice-like structure to facilitate collapsed accommodation within an interventional delivery instrument such as a sheath.

In some embodiments, the inner stent is configured to at least partially maintain the compressed state when the radial compressive force is removed from the inner stent after being radially compressed from the expanded state to the compressed state under the radial compressive force. The outer stent of a prosthetic valve fixation device according to the present application may at least partially self-resume diameter while the inner stent may at least partially remain in a compressed diameter when extended distally from the interventional delivery instrument during implantation, thereby preserving space therebetween for capturing the leaflets of the native valve.

In some embodiments, the inner stent is configured to expand radially from a compressed state to an expanded state when a radially outward force is applied to the inner stent with the inner stent in a compressed state. After the petals She Buzhuo of the native valve are in the space between the inner and outer stents, the outer diameter of the inner stent may be expanded to approximate the inner diameter of the outer stent by means of radial expansion of an instrument, such as a balloon, disposed inside the inner stent, thereby sandwiching the leaflets therebetween.

In some embodiments, the inner stent is made of a non-shape memory material (i.e., a material that does not have shape memory properties or superelasticity), such as cobalt chrome or stainless steel. An inner stent made of these materials can maintain the size of the compressed state after being compressed and the compression force removed, and can recover the size of the expanded state when the expansion force is applied.

Another aspect of the present application relates to a valve replacement device comprising a prosthetic valve fixation device and a prosthetic valve according to any of the embodiments described above. The periphery of the prosthetic valve is secured to the inner surface of the inner stent. In some embodiments, the prosthetic valve may be made of natural materials such as porcine pericardium, bovine pericardium, or synthetic biocompatible synthetic materials.

Drawings

A prosthetic valve fixation device and a valve replacement device according to embodiments of the present application are described below with reference to the accompanying drawings. As used hereinafter, the term "prosthetic valve" refers to a membranous one-way valve structure made of natural or biocompatible synthetic material, such as porcine pericardium, bovine pericardium, etc., and functioning to open and close with the respective ventricles, atria, and diastole of the heart, without the inclusion of a means to secure the structure to the implantation site; the term "prosthetic valve fixation device" refers to a device for carrying such a "prosthetic valve" and securing the "prosthetic valve" to an implantation site; and the term "valve replacement device" refers to the entirety of such "prosthetic valve fixation device" in combination with such "prosthetic valve", wherein the perimeter of the "prosthetic valve" may be secured to the inside of the "prosthetic valve fixation device".

It is to be understood that the drawings are designed solely for the purposes of illustration and description and are not intended to limit the scope of the application. In addition, the drawings are merely schematic representations, not necessarily drawn to scale, of the various components and combinations thereof, wherein:

FIG. 1 is a schematic perspective view illustrating a prosthetic valve fixation device in a deployed state according to an embodiment of the present application;

FIG. 2 is a schematic perspective view illustrating a prosthetic valve fixation device in a compressed state according to an embodiment of the present application;

FIG. 3 is a schematic perspective view illustrating the retraction of a valve replacement device within an interventional delivery instrument in accordance with an embodiment of the present application;

FIG. 4 is a schematic perspective view illustrating the extension of a valve replacement device from an interventional delivery instrument according to an embodiment of the present application;

fig. 5A is a schematic perspective view illustrating a valve replacement device during a leaflet capturing procedure according to an embodiment of the present application;

fig. 5B is a schematic bottom view illustrating a valve replacement device during a leaflet capturing procedure according to one embodiment of the present application;

fig. 5C is a schematic bottom view illustrating a valve replacement device during a leaflet capturing procedure according to another embodiment of the present application;

Fig. 6A is a schematic perspective view illustrating a valve replacement device during a leaflet clamping procedure according to an embodiment of the present application;

fig. 6B is a schematic bottom view illustrating a valve replacement device during a procedure of clamping leaflets according to one embodiment of the present application;

fig. 6C is a schematic bottom view illustrating a valve replacement device during a leaflet clamping procedure according to another embodiment of the present application;

fig. 7A is a schematic perspective view illustrating a valve replacement device after implantation is completed, according to an embodiment of the present application;

fig. 7B is a schematic bottom view illustrating a valve replacement device after implantation is complete, according to one embodiment of the present application;

fig. 7C is a schematic bottom view illustrating a valve replacement device after implantation is completed according to another embodiment of the present application.

In some of these drawings, the illustration of some components may be omitted for clarity of illustration or to avoid obscuring the drawings, etc., which should not be construed to mean that no corresponding components are included in the illustrated embodiments.

Detailed Description

A prosthetic valve fixation device and a valve replacement device incorporating the same, and implantation procedures thereof, according to embodiments of the present application, are described in detail below with reference to the drawings, wherein like reference numerals designate identical or corresponding elements throughout the several views. As used herein, the term "distal" refers to a direction in which a prosthetic valve fixation device, a valve replacement device, an interventional delivery instrument (such as a sheath, etc.), etc., or components thereof, are farther from an operator (such as a physician) (such as, for example, the lower left side of each of the schematic perspective views 1, 2 and the lower right side of each of the schematic perspective views 3, 4, 5A, 6A, 7A; particularly, for an aortic valve, a direction perpendicular to the aortic valve plane pointing from the aorta to the left ventricle), while the term "proximal" refers to a direction in which a prosthetic valve fixation device, a valve replacement device, an implantation instrument, an interventional delivery instrument (such as a sheath, etc.), etc., or components thereof, are closer to an operator (such as, for example, the upper right side of each of the schematic perspective views 1, 2 and the upper left side of each of the schematic perspective views 3, 4, 5A, 6A, 7A, and particularly, for an aortic valve, a direction perpendicular to the aortic valve plane pointing from the left ventricle to the aorta). In other words, during the implantation procedure, the "distal" end of the prosthetic valve fixation device, valve replacement device, implantation instrument (interventional delivery instrument such as a sheath), etc., or of the inner stent, outer stent, etc., is the end that is advanced into the patient, while the "proximal" end is the other end that is advanced into the patient. In this application, "valve" is used interchangeably with other valves, such as aortic valves, pulmonary valves, etc., as prosthetic valve fixation devices and valve replacement devices according to the present application may be adapted for repair of a variety of valves, with the specific configuration of the inner and outer stents being adjusted according to the number, size, morphology, and treatment requirements of the leaflets being treated. Thus, while the structure, function, and effects of the prosthetic valve fixation device and valve replacement device according to the present application are explained below, possibly for the case of treatment of aortic valve bileaflet deformities (hereinafter used interchangeably with "bileaflet"), it is to be understood that these components and their effects and benefits are equally applicable to the repair treatment of diseases of other valves.

One aspect of the present application relates to a prosthetic valve fixation device 100. Fig. 1 is a schematic perspective view illustrating a prosthetic valve fixation device 100 in a deployed state according to an embodiment of the present application. As shown in fig. 1, the prosthetic valve fixation device 100 may include an outer stent 120 and an inner stent 140, with the outer stent 120 being radially sleeved outside of the inner stent 140. The inner stent 140 may have an open proximal end 146, an open distal end 142, and a tubular sidewall 144 extending along the longitudinal axis of the prosthetic valve fixation device 100 between the open proximal end 146 and the open distal end 142. The outer bracket 120 may have a three-dimensional ring shape. In other words, the outer stent 120 generally completely surrounds the outside of the inner stent 140, but the annular structure of the outer stent 120 may not be in the same plane, but rather contain distal and/or proximal undulations along the longitudinal axis of the prosthetic valve fixation device 100 to form an annular shape in three dimensions to facilitate capturing and gripping the leaflets of a native valve, as will be described in greater detail below with reference to the figures. In other words, the outer bracket 120 may be annular end-to-end in a bottom view looking along the longitudinal axis, and may present a non-planar structure that projects distally and/or proximally along the longitudinal axis in a side view looking along the radial direction. By clamping the leaflets of the native valve between the inner and outer stents 140, 120, the prosthetic valve fixation device 100 can position the carried prosthetic valve in the native valve position by means of the native leaflets without relying entirely on radial support forces to bear on the inner periphery of the valve annulus of the native valve.

In some embodiments, the outer stent 120 may be fixedly connected to the inner stent 140 in an axial direction along the longitudinal axis. In this case, no significant axial relative movement between the outer and inner stents 120, 140 will occur as the device changes between a contracted state (e.g., radially compressed to contract for receipt within the interventional delivery device) and an expanded state (e.g., expanded after extension from within the interventional delivery device in preparation for capture of the leaflets). Accordingly, the interventional delivery device need not be equipped with means for delivering and releasing the outer stent 120 and the inner stent 140, respectively, thereby simplifying the complexity of the interventional delivery device and the complexity of the implantation procedure, avoiding that an increase in the delivery outer diameter affects the pushing efficiency. In addition, this avoids relative axial position errors or misalignment that may be introduced when the outer stent 120 is axially moved relative to the inner stent 140, thus reducing the risk of implant failure. In some embodiments, the outer stent 120 may be stitched or bound to the inner stent 140 axially fixedly by a thin wire such as nitinol wire, or may be completely fixedly attached to the inner stent 140 by welding, soldering, or the like.

Fig. 2 is a schematic perspective view illustrating a prosthetic valve fixation device 100 in a compressed state according to an embodiment of the present application. As shown in fig. 2, both the inner stent 140 and the outer stent 120 of the prosthetic valve fixation device 100 contract in a radial direction to a smaller radial dimension upon being subjected to a radial compressive force. Still referring to fig. 2, in some embodiments, since the outer stent 120 may be fixedly connected to the inner stent 140 in an axial direction along the longitudinal axis, the relative axial position between the outer stent 120 and the inner stent 140 does not change in the contracted state as compared to the expanded state shown in fig. 1. The application of radial compressive forces to the prosthetic valve fixation device 100 may be performed by means existing in the art or yet to be developed, such as by crimping devices or loading tools, to collapse the device contained within an interventional delivery instrument, such as a sheath, as shown in fig. 3. In some embodiments, the inner stent 140 in a contracted state may be peripherally threaded with an inflation device, such as a balloon, as will be described in more detail below with reference to the figures.

In some embodiments, after the prosthetic valve fixation device 100 is contracted to the contracted state shown in fig. 2 under the force of radial compression, the outer stent 120 may self-expand to at least partially return to the original radial dimension in the expanded state shown in fig. 1 when the radial compression force is removed from the prosthetic valve fixation device 100 (e.g., when the prosthetic valve fixation device 100 is extended from the distal end of an interventional delivery instrument such as a sheath during implantation). By virtue of the self-expanding nature, the outer stent 120 of the prosthetic valve fixation device 100 according to the present application can at least partially self-recover in diameter when extended from the distal end of the interventional delivery instrument during implantation, and portions of the outer stent 120 can at least partially recover the original shape in the deployed state. Thus, the circumferential angle of the prosthetic valve fixation device 100 need only be adjusted prior to capturing the leaflets of the native valve, rather than having to use an inflation device such as a balloon to restore or enlarge the diameter of the outer stent 120. It will be appreciated that this simplifies the steps that need to be performed during the implantation procedure and shortens the surgical time, which may improve the prognosis of the patient.

In some embodiments, the outer stent 120 is made of a shape memory material or a superelastic material. In some embodiments, the shape memory material is a shape memory alloy, for example a shape memory nickel titanium alloy, such as Nitinol (Nitinol), which has good shape memory properties. Alternatively, the outer stent 120 may also be made of other shape memory materials or super-elastic materials with biocompatibility and durability, such as metals or polymeric materials with shape memory or super-elastic properties, existing or yet to be developed in the art. The shape memory or superelastic properties of the material enable the outer stent 120 to have the self-expanding properties described above, i.e., to recover to a greater extent to the original radial dimension of the expanded state upon removal of the radial compressive force, such as to recover to greater than 90%, preferably greater than 95%, more preferably greater than 99%, and most preferably to recover fully to the original diameter.

In some embodiments, the three-dimensional annular shape of the outer stent 120 may include at least two distal raised portions 122, each distal raised portion 122 protruding distally along the longitudinal axis of the prosthetic valve fixation device 100 in a side view in the radial direction. The distal raised portion 122 serves to capture and clamp the respective leaflet of the native valve between itself and the inner stent 140. During the implantation procedure, the outer stent 120 may laterally encase the leaflets of the native valve in a distal direction from the proximal to the distal. The distal raised portion 122 may face the leaflet in a distal direction so as to capture it into the space between the outer stent 120 and the inner stent 140 in a contracted state, as will be described in more detail below with reference to fig. 4-6C. In some embodiments, each distal raised portion 122 may have a "U" shape with the curved base of the "U" shape extending distally along the longitudinal axis. The "U" shape has rounded edges to avoid damaging or irritating the leaflets of the native valve. In some embodiments, as shown in fig. 1, each pair of adjacent distal raised portions 122 may be joined together at a respective proximal connecting portion 124 to form a complete three-dimensional annular shape of the outer stent 120. In some embodiments, as shown in fig. 1, each proximal connection portion 124 may be loosely or tightly stitched/tied by wire, or fixedly connected to the outer circumference of the inner stent 140 by welding, soldering, or the like, such that the outer stent 120 is fixedly connected to the inner stent 140 in an axial direction along the longitudinal axis.

Additionally, in some embodiments, at least two distal raised portions 122 of the three-dimensional annular shape of the outer stent 120 described above may comprise a pair of opposing distal raised portions 122 that are joined together at a pair of proximal connecting portions 124, as shown in fig. 1 and 2. In this case, the pair of opposing distal raised portions 122 may each be used to capture and clamp a respective leaflet of a pair of leaflets between itself and the inner stent 140. Thus, the prosthetic valve fixation device 100 according to these embodiments is particularly useful for the treatment of valve diseases having two leaflets, such as the treatment of simple regurgitation aortic valve bileaflet deformities without stenosis and calcification. Even if the annulus of a bi-lobated aortic valve of a patient with the disease is not able to achieve the mounting of the prosthetic valve fixation device 100 by radial support alone due to tissue softness, the prosthetic valve fixation device 100 according to these embodiments can position the prosthetic valve at the location of the native aortic valve by clamping a pair of leaflets between the pair of opposing distal raised portions 122 of the outer stent 120 and the inner stent 140.

In some embodiments, the three-dimensional annular shape of the outer stent 120 forms a portion of the tubular sidewall 144 in the deployed state. In other words, in a bottom view seen from the distal side to the proximal side as shown in fig. 5B, 5C, 6B, 6C, 7B, and 7C, for example, the outer stent 120 in the deployed state takes on a circular ring shape. As an example, the cylindrical barrel of material may be cut by a laser cutting or the like process to make a three-dimensional annular shape of the outer bracket 120. Alternatively, when the inner annulus wall of the native valve deviates significantly from the cylindrical shape, a barrel of material that mimics the shape of the native annulus may also be cut to make the three-dimensional annular shape of the outer stent 120. In this case, when the prosthetic valve fixation device 100 is implanted with the longitudinal axis perpendicular to the plane of the native valve, the three-dimensional annular shape of the outer stent 120 in the deployed state may generally best match the shape of the inner annular wall of the native valve, as will be described in more detail below with reference to fig. 7A.

Since it is not necessary to rely on radial support forces to support the valve annulus circumference of the native valve, the prosthetic valve fixation device 100 according to embodiments of the present application may be suitable for treatment of stentless, calcififree valve diseases even though the native valve annulus may not provide sufficient reaction forces for radial support of the prosthetic valve fixation device 100 due to tissue softness. Accordingly, in some embodiments, the outer diameter of the outer stent 120 in the deployed state may be no greater than the inner diameter of the annulus of the native valve, and thus may not substantially create radially outward supporting forces after implantation, so as not to cause any additional damage to the annulus. In other words, after implantation, the outer diameter of the outer stent 120 may be exactly equal to the inner diameter of the annulus of the native valve to fit around the annulus, but without the need to create a radially expanding force on the annulus, or with only a small radially expanding force; alternatively, the outer diameter of the outer stent 120 may also be slightly larger or smaller than the inner diameter of the annulus of the native valve to facilitate positioning and manipulation during implantation. It will be appreciated that the diameter of the outer stent 120 should not be too small to create perivalvular leakage. Preferably, the outer diameter of the outer stent 120 in the deployed state is 15 mm-30 mm, so that the outer diameter of the prosthetic valve fixation device 100 of embodiments of the present application is smaller than the outer diameter of the prosthetic valve stent required in the prior art when the inner diameter of the annulus of the native valve is constant.

In some embodiments, the tubular sidewall 144 of the inner stent 140 may have a mesh-like structure to facilitate improved radial compressibility so as to be more conveniently shrink-received within an interventional delivery instrument with a smaller delivery outer diameter (profile). In some embodiments, the mesh-like structure may be comprised of polygonal mesh, such as hexagonal mesh, quadrilateral mesh, or a combination thereof, in the expanded state. It will be appreciated that the inner stent 140 constructed of hexagonal mesh and quadrangular mesh is more easily compressed to a smaller radial dimension or expanded back to the original radial dimension than a mesh of a stable shape such as a triangular mesh.

In some embodiments, the inner stent 140 may be configured to at least partially maintain the compressed state when the radial compressive force is removed from the inner stent after being radially compressed from the expanded state to the compressed state under the force of the radial compressive force. In other words, the inner stent 140 does not have self-expanding properties, or at least does not spontaneously fully expand back to its original radial dimension in the deployed state. Upon distal extension from the interventional delivery instrument during implantation, the outer stent 120 of the prosthetic valve fixation device 100 may at least partially self-resume to the original diameter in the expanded state, while the inner stent 140 may at least partially remain in the compressed radial dimension without spontaneously fully expanding back to the original radial dimension in the expanded state, thereby preserving space between the inner stent 140, the outer stent 120 to capture the leaflets of the native valve, as will be described in greater detail below with reference to fig. 4-5C.

In some embodiments, the inner stent 140 may be configured such that, in a compressed state, when a radially outward force is applied to the inner surface of the inner stent 140, the inner stent 140 may expand radially from the compressed state to an original radial dimension in the expanded state. After the petals She Buzhuo of the native valve are in the space between the inner stent 140 and the outer stent 120, the outer diameter of the inner stent 140 can be expanded to approximate the inner diameter of the outer stent 120 by means of radial expansion of a balloon or like instrument disposed inside the inner stent 140, thereby clamping the petals therebetween, as will be described in more detail below with reference to fig. 6A-6C.

In some embodiments, inner stent 140 may be made of a non-shape memory material. In other words, the material from which the inner stent 140 is made may not possess self-expanding properties, shape memory properties, or superelasticity. In some embodiments, the material may be cobalt chrome or stainless steel, or a more rigid material with biocompatibility and durability that is present or yet to be developed in the art. It will be appreciated that inner stent 140 made of these materials is capable of at least partially maintaining the radial dimension in a compressed state after being compressed and the compressive force removed, and is capable of recovering the radial dimension in a deployed state upon application of an expansive force.

In some embodiments, the inner stent 140 and/or the outer stent 120 may be coated with a biocompatible coating, such as polyethylene terephthalate (PET), to improve biocompatibility, reduce rejection reactions, and promote endothelialization.

Another aspect of the present application relates to a valve replacement device comprising the prosthetic valve fixation device 100 and the prosthetic valve of any of the embodiments of the above aspects. In some embodiments, the periphery of the prosthetic valve may be secured to the inner surface of the inner stent 140 to form, in conjunction with the prosthetic valve fixation device 100 and the annulus of the native valve, an integral body that performs the function of the prosthetic valve. In some embodiments, the prosthetic valve may have, for example, three leaflets and be sewn to the inner surface of the inner stent 140 at several points around its periphery or otherwise secured to the inner surface of the inner stent 140 with a base (not shown) or the like. In some embodiments, the prosthetic valve may be made from a membrane of material existing or yet to be developed in the art, natural materials such as porcine pericardium, bovine pericardium, or synthetic materials that are biocompatible and durable.

The implantation process of a valve replacement device comprising a prosthetic valve fixation device 100 and a prosthetic valve according to the present application is explained below with reference to fig. 3-7C. Although in these figures and the following description, the treatment of an aortic valve bileaflet deformity is described with reference to and the prosthetic valve fixation device 100 is illustrated and described as including a pair of distal raised portions 122, the prosthetic valve fixation device 100 and valve replacement device according to the present application may also include a greater number (e.g., three) of distal raised portions 122 and be used to treat valve disease of valves having three leaflets (such as aortic valves other than bileaflet deformity, pulmonary valve, tricuspid valve, etc.). In addition, in these figures, the illustration of the prosthetic valve may be omitted for clarity of illustration and to avoid obscuring, but only the prosthetic valve fixation device 100 is shown, which does not indicate that the prosthetic valve is not involved in these implantation procedures.

Fig. 3 is a schematic perspective view illustrating the contraction of a valve replacement device within an interventional delivery instrument 200 according to an embodiment of the present application. In the contracted state shown in fig. 3, the valve replacement device is delivered to the vicinity of the aortic valve site by a minimally invasive surgical procedure, such as femoral artery intervention, with an interventional delivery instrument 200, such as a sheath. As shown in fig. 3, the prosthetic valve fixation device 100 is radially compressed to a contracted size in a compressed state and is contracted to be received within the interventional delivery instrument 200. At this point, the inner stent 140 and the outer stent 120 of the prosthetic valve fixation device 100 may both be radially compressed, and the inner stent 140 and the outer stent 120 are positioned near the distal end of the interventional delivery instrument 200, such as a sheath. Although not shown, the prosthetic valve of the valve replacement device may also be contracted inside the inner stent 140 at this time. In addition, an inflation device (not shown in FIG. 3), such as a balloon, may also be sleeved inside the contracted inner stent 140 to expand the inner stent 140 without self-expanding properties to return to the radial dimension of the expanded state in a subsequent operation. In some embodiments, the balloon may be attached to the distal end of a catheter (not shown) to form a balloon catheter, and the balloon catheter may also be moved axially along a guidewire (not shown) to deliver the valve replacement device and sheath to the target site.

Fig. 4 is a schematic perspective view illustrating the protrusion of a valve replacement device from an interventional delivery instrument 200 according to an embodiment of the present application. As an example, upon reaching the target site, the valve replacement device may be advanced from the distal end of the sheath by distal movement of the balloon catheter relative to the sheath. It will be appreciated that the valve replacement device as a whole is still located proximal to the aortic valve, i.e. on the aortic side without passing through the aortic valve plane to the left ventricular side. At this point, the outer stent 120 self-expands to at least partially return to the original radial dimension in the expanded state, while the inner stent 140 remains at least partially in the contracted radial dimension in the contracted state, due to the self-expanding nature of the shape memory material or super-elastic material of the outer stent 120. In this case, the pair of distal raised portions 122 of the outer stent 120 of the prosthetic valve fixation device 100 can be aligned circumferentially with the pair of native leaflets of the bi-leaflet malformed aortic valve, respectively, by rotating the valve replacement device in preparation for capturing the pair of native leaflets.

Fig. 5A is a schematic perspective view illustrating a valve replacement device during a leaflet capturing procedure according to an embodiment of the present application. As shown in fig. 5A, after the extension and alignment operations described above with reference to fig. 4 are completed, the valve replacement device is moved distally (from the aorta to the left ventricular direction, for example) until the distal ends of the outer stent 120 and/or the inner stent 140 substantially abut against the proximal side of the aortic valve (i.e., the aortic side) to position the pair of native valves She Tao in the space between the pair of distal raised portions 122 of the expanded outer stent 120 and the contracted inner stent 140. At this time, the outer stent 120 may be substantially fitted to the annulus 300 of the aortic valve, but does not rely on radial support forces between the outer stent 120 and the annulus 300 to secure the prosthetic valve fixation device 100.

Fig. 5B is a schematic bottom view (as exemplified by an aortic valve, view from the left ventricle toward the aorta) illustrating a valve replacement device during a procedure of capturing the leaflets according to an embodiment of the application. As shown in fig. 5B, the inner stent 140 is now over-fitted over the outer circumference of the expansion device 400, such as a balloon, along with the prosthetic valve 500, while the outer stent 120 has self-expanded to a radial dimension that approximates or equals the inner diameter of the annulus 300. In the present embodiment, the outer bracket 120 and the inner bracket 140 are fixedly connected to each other only in the axial direction, and are not necessarily fastened together in the radial direction. As an example, the outer stent 120 may be loosely bundled/sewn with wire at a pair of proximal connecting portions 124 to corresponding locations on the inner stent 140. In this case, there may be a radial space d1 between the distal convex portion 122 of the outer stent 120 and the inner stent 140 for accommodating the native leaflets. In addition, as shown in fig. 5B, the prosthetic valve 500 may now be expanded by an inflation device 400, such as a balloon, to attach to the inside of the inner stent 140.

Fig. 5C is a schematic bottom view (as exemplified by an aortic valve, view from the left ventricle toward the aorta) illustrating a valve replacement device during a procedure of capturing leaflets according to another embodiment of the application. In contrast to the embodiment shown in fig. 5B, the outer stent 120 in the embodiment shown in fig. 5C may be secured to each other at a pair of proximal connecting portions 124 with the inner stent 140 by means such as welding, soldering, or tight wire binding/sewing. Thus, when the outer stent 120 is extended out of the sheath and self-expands, the inner stent 140 is also at least partially expanded in a direction corresponding to the pair of proximal connecting portions 124 of the outer stent 120. In contrast, the inner stent 140 remains at least partially in the radial dimension in the contracted state in a direction corresponding to the pair of distal raised portions 122 of the outer stent 120 to leave a d2 radial space between it and the distal raised portions 122 of the outer stent 120 for receiving leaflets of a native valve captured. It will be appreciated that in this case, the prosthetic valve 500 also deploys at least partially with the inner stent 140 in a direction corresponding to the pair of proximal connecting portions 124 of the outer stent 120 and still rests against the balloon that has not yet been inflated.

Fig. 6A is a schematic perspective view illustrating a valve replacement device during a procedure of clamping a leaflet, wherein the illustration of the prosthetic valve is omitted to show the arrangement of the balloon, according to an embodiment of the present application. After capturing and positioning a pair of native leaflets into the space between the pair of distal raised portions 122 of the deployed outer stent 120 and the contracted inner stent 140, an inflation device 400, such as a balloon, that is sleeved within the inner stent 140 is radially expanded, as shown in fig. 6A, thereby radially expanding the inner stent 140 to a radial dimension that at least partially resumes the deployed state, to firmly clamp the captured native leaflets v1, v2 between the outer stent 120 and the inner stent 140. After this, the native leaflets v1, v2 will always be in an open state as they are clamped, no longer functioning as an open-close valve, and the valve replacement device has been secured in place at the native valve by means of clamping the native leaflets v1, v 2.

Fig. 6B is a schematic bottom view (as exemplified by an aortic valve, view from the left ventricle toward the aorta) illustrating a valve replacement device during a procedure of clamping the leaflets according to an embodiment of the application. Corresponding to the embodiment shown in fig. 5B, in the embodiment shown in fig. 6B, the outer stent 120 may be loosely bundled/sewn with wire at a pair of proximal connecting portions 124 to corresponding locations on the inner stent 140. As shown in fig. 6B, during the leaflet clamping process shown in fig. 6A, an inflation device 400, such as a balloon, is inflated such that the inner stent 140 expands in radial dimension until it approaches the inner diameter of the outer stent 120. At this time, the radial space between the inner stent 140 and the pair of distal convex portions 122 of the outer stent 120 is reduced to d3 to firmly clamp the captured native leaflets v1, v2 between the inner stent 140 and the distal convex portions 122. It will be appreciated that during this process, the prosthetic valve 500 is pushed by the expansion device 400 against the inner wall of the inner stent 140. After this process, the prosthetic valve fixation device 100, along with the carried prosthetic valve 500, has been fixed in place at the native valve by clamping the native leaflets v1, v 2.

Fig. 6C is a schematic bottom view (as exemplified by an aortic valve, view from the left ventricle toward the aorta) illustrating a valve replacement device during a procedure of clamping the valve leaflets according to another embodiment of the application. Similar to the embodiment shown in fig. 6B, which corresponds to the embodiment shown in fig. 5B, the embodiment shown in fig. 6C may correspond to the embodiment shown in fig. 5C, wherein the outer stent 120 may be secured to the inner stent 140 at a pair of proximal connecting portions 124 by means such as welding, soldering, or wire tight binding/sewing. Similarly, after expanding the inner stent 140 using the expansion device 400, the radial space between the inner stent 140 and the pair of distal raised portions 122 of the outer stent 120 is reduced to d4 to firmly clamp the captured native leaflets v1, v2 between the inner stent 140 and the distal raised portions 122.

Fig. 7A is a schematic perspective view illustrating a valve replacement device after implantation is completed, wherein the illustration of the prosthetic valve is omitted for clarity of illustration of the inner stent 140 and the annulus 300, in accordance with an embodiment of the present application. After grasping the native leaflets v1, v2, the inflation device 400, such as a balloon, is contracted and the interventional delivery instrument (not shown in fig. 7A), such as a guidewire, sheath, and balloon catheter, is removed from the patient. To this end, the implantation process of the valve replacement device according to embodiments of the present application is completed. After the expansion device 400 is contracted, the prosthetic valve (not shown in fig. 7A) is restored to its normal operating state by being abutted against the inner wall of the inner stent 140, thereby replacing the function of the native aortic valve, i.e., opening and closing with contraction and relaxation of the left ventricle, respectively.

Fig. 7B is a schematic bottom view (in the case of an aortic valve, view from the left ventricle toward the aorta) illustrating a valve replacement device after implantation is complete, according to an embodiment of the application. Corresponding to the embodiment shown in fig. 5B, 6B, in the embodiment shown in fig. 7B, the outer stent 120 may be loosely bundled/sewn with wire at a pair of proximal connecting portions 124 to corresponding locations on the inner stent 140. After implantation is complete and the instruments such as the expansion device 400, guidewire and sheath are removed, the prosthetic valve 500 returns to its normal operating state and expands inside the inner stent 140 of the prosthetic valve fixation device 100, as shown in fig. 7B.

Fig. 7C is a schematic bottom view (in the case of an aortic valve, view from the left ventricle toward the aorta) illustrating a valve replacement device according to another embodiment of the application after implantation is completed. In contrast to the embodiment shown in fig. 7B, which corresponds to the embodiment shown in fig. 5B, 6B, the embodiment shown in fig. 7C may correspond to the embodiment shown in fig. 5C, 6C, wherein the outer stent 120 may be secured to the inner stent 140 at a pair of proximal connecting portions 124 by means such as welding, soldering, or wire tight binding/sewing.

As shown in fig. 5B, 5C, 6B, 6C, 7B, and 7C, since the prosthetic valve fixation device 100 according to the present application does not rely on radial support forces between the outer stent 120 and the annulus 300 to secure the prosthetic valve, the outer diameter of the outer stent 120 may be no greater than the inner diameter of the annulus 300 of the native valve after implantation. In other words, after implantation is complete, the outer diameter of the outer stent 120 may be exactly equal to the inner diameter of the annulus 300 of the native valve to fit around the inner circumference of the annulus 300 without applying high radially expanding forces to the annulus 300. Thus, the prosthetic valve fixing device 100 can be stably positioned without using a support with high rigidity and radial supporting force, and meanwhile, the prosthetic valve fixing device 100 can be kept with good flexibility and adherence, so that risks of perivalvular leakage, damage to an annulus and the like are reduced while displacement is avoided. Alternatively, the outer diameter of the outer stent 120 may also be slightly larger or slightly smaller than the inner diameter of the annulus 300 of the native valve after implantation. Preferably, the outer diameter of the outer stent 120 after implantation ranges from 15mm to 30mm. In addition, as shown in fig. 3-7C, which illustrate the implantation procedure, no axial (i.e., distal or proximal) relative movement occurs between the inner stent 140 and the outer stent 120 during the implantation procedure. This simplifies the complexity of the interventional delivery instrument 200 and the complexity of the implantation procedure. In addition, the risk of implant failure is reduced by avoiding errors or misalignments that may be introduced by relative axial movement between the outer stent 120 and the inner stent 140.

It will be appreciated that various modifications may be made to the disclosed apparatus. Thus, the above description should not be taken as limiting, but merely as exemplifications of embodiments of the disclosure. Other modifications within the scope and spirit of this disclosure will occur to persons of ordinary skill in the art. For example, any and all features of one described embodiment may be suitably integrated into another embodiment, and the benefits of that feature in one embodiment are expected to be realized in another embodiment.

Claims (15)

1. A prosthetic valve fixation device for securing a prosthetic valve to a leaflet of a native valve, comprising:

an inner stent having an open proximal end, an open distal end, and a tubular sidewall extending along a longitudinal axis of the prosthetic valve fixation device between the open proximal end and the open distal end; and

an outer bracket having a three-dimensional annular shape extending in an axial direction in a bending manner and configured to be sleeved on a radially outer side of the inner bracket;

wherein the inner and outer stents are configured to clamp each leaflet of the native valve between the inner and outer stents to secure the prosthetic valve securing device to the leaflets of the native valve, an

Wherein the outer stent is connected to the inner stent in an axial direction along the longitudinal axis.

2. The prosthetic valve fixation device of claim 1, wherein the outer stent is configured to at least partially self-expand to return to an original radial dimension in the expanded state when the radial compressive force is removed from the outer stent after being radially compressed from the expanded state to a contracted radial dimension in the compressed state under the force of the radial compressive force.

3. The prosthetic valve fixation device of claim 2, wherein the outer diameter of the outer stent in the deployed state is 15mm to 30mm.

4. The prosthetic valve fixation device of claim 2, wherein the outer stent is made of a shape memory material or a superelastic material.

5. The prosthetic valve fixation device of claim 4, wherein the shape memory material is a shape memory nickel titanium alloy.

6. The prosthetic valve fixation device of claim 1, wherein the three-dimensional annular shape of the outer stent comprises at least two distal raised portions, each of the at least two distal raised portions for sandwiching a respective leaflet of the native valve between the respective distal raised portion and the inner stent.

7. The prosthetic valve fixation device of claim 5, wherein each of the at least two distal protruding portions has a "U" shape.

8. The prosthetic valve fixation device of claim 5, wherein each pair of adjacent distal protruding portions of the at least two distal protruding portions are connected together at a proximal connection portion.

9. The prosthetic valve fixation device of claim 8, wherein the proximal connection portion is fixedly connected to the inner stent.

10. The prosthetic valve fixation device of claim 1, wherein the outer stent is connected to the inner stent by wire stitching or binding, welding or fusion.

11. The prosthetic valve fixation device of claim 1, wherein the inner stent has a compressible lattice-like structure.

12. The prosthetic valve fixation device of claim 11, wherein the inner stent is configured to at least partially retain the compressed state when the radial compressive force is removed from the inner stent after being radially compressed from the expanded state to the compressed state under the radial compressive force.

13. The prosthetic valve fixation device of claim 12, wherein the inner stent is configured to expand radially from the compressed state to the expanded state when a radially outward force is applied to the inner stent with the inner stent in the compressed state.

14. The prosthetic valve fixation device of claim 11, wherein the material of the inner stent is cobalt chrome or stainless steel.

15. A valve replacement device, comprising:

the prosthetic valve fixation device according to any one of claims 1-14; and

a prosthetic valve of the type comprising a plurality of valve elements,

wherein the periphery of the prosthetic valve is secured to the inner surface of the inner stent.

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