CN216365426U - Prosthetic valve fixation device and valve replacement device comprising same - Google Patents

Abstract

The present application relates to 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; the outer support is provided with a three-dimensional annular shape extending along the axial direction in a bending way and is configured to be sleeved on the radial outer side of the inner support; wherein the inner stent and the outer stent are configured to clamp each leaflet of the native valve in between the inner stent and the outer stent to secure the prosthetic valve fixation device over the leaflets of the native valve, and wherein the outer stent is fixedly connected to the inner stent in an axial direction along the 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

Valvular diseases are common cardiovascular diseases including malformations caused by congenital dysplasia or acquired disease and aging, valvular stenosis, calcification, incompetence and regurgitation. These valvular diseases alter the normal flow mechanics of the blood and, in turn, cause a range of symptoms such as panic, shortness of breath, fatigue, edema, angina, fainting, etc. after activity. In particular, aortic valve calcification, stenosis, and insufficiency and regurgitation are common valve diseases.

For patients with calcified and stenotic Aortic valves, the recently used trans-sheath 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 the balloon is radially expanded to pinch the native valve open to expose the annulus. A prosthetic valve (such as one made from porcine pericardium) secured to a prosthetic valve fixation device is then collapsed and contained in an interventional delivery device and delivered to the aortic valve area via, for example, the femoral artery. After reaching the aortic valve region, the balloon fitted over the interior of the prosthetic valve fixture is again radially expanded to force the prosthetic valve fixture to radially expand and thereby radially seat within the annulus of the aortic valve. After removal of the balloon and interventional delivery device, the implanted prosthetic valve replaces the function of the native valve, acting to open and close as the left ventricle contracts and relaxes. The prosthetic valve fixation device described above can be more securely fixed within such an annulus due to aortic valve calcification and the annulus of the native aortic valve of a stenotic patient, which can provide a strong counter force for radial support of the prosthetic valve fixation device.

However, for patients with simple aortic regurgitation (aortic valve stenosis and calcification), the annulus tissue of the native aortic valve is generally softer and does not provide sufficient radial support. In such cases, it is often difficult to secure the prosthetic valve at the native annulus with radial support forces using the prosthetic valve fixation devices described above. In addition, in the case of a patient having aortic mitral valve malformation accompanied by simple regurgitation, without stenosis and calcification, it is also difficult to treat the disease using the above-mentioned prosthetic valve-fixing device because the annular tissue is generally soft. It can be seen that in the field of valve replacement devices, there is a need for a prosthetic valve fixation device with an improved way of fixation and a valve replacement device comprising the same to address the problem of fixation of a prosthetic valve in the treatment of patients with stenosis-free and calcification-free valves, such as simple regurgitation disease of the aortic valve, the pulmonary valve, etc.

SUMMERY OF THE UTILITY MODEL

Prosthetic valve fixation devices and valve replacement devices incorporating the same according to embodiments of the present application at least partially address the above issues and others discussed below. One aspect of the present application relates to a prosthetic valve fixation device for securing a prosthetic valve to leaflets of a native valve. The prosthetic valve fixation device can include an inner stent and an outer stent. The inner stent can 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 bracket may have a three-dimensional annular shape extending in an axial bending direction, and may be configured to fit over a radially outer side of the inner bracket. The inner stent and the outer stent may be configured to clamp each leaflet of the native valve between the inner stent and the outer stent to secure the prosthetic valve fixation device over 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 prosthetic valve carried by means of the leaflets of the native valve without relying on radial support force to support on the inner circumference of the annulus, thus being suitable for calcifyless and stenotic valve disease patients. The three-dimensional, generally annular shape of the outer stent can "nest" the leaflets of the native valve from the outside, while the inner stent can 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 device and the implantation procedure and reducing the risk of operational failure.

In some embodiments, the outer scaffolding is configured to at least partially self-expand to return to an original radial dimension in the expanded state when a radial compressive force is removed from the outer scaffolding after being radially compressed from the expanded state to a contracted radial dimension in the compressed state under the action 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-restore its diameter when extended from the distal end of 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 expansion device such as a balloon to restore or enlarge the diameter of the outer stent.

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

In some embodiments, the external bolster 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 self-return to the original diameter of the deployed state to a large extent, such as to more than 90%, preferably more than 95%, more preferably more than 99%, and most preferably completely to the original diameter. In addition, the material also has excellent biocompatibility to reduce rejection reaction.

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 outside nests the leaflets of the native valve in a distal direction from the proximal to the distal. The distal convex portion faces the valve leaflets in a distal direction so as to be captured in a 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 connected together at a proximal connecting portion to connect them to form a complete three-dimensional annular shape of the external bolster.

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 welding.

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

In some embodiments, the inner stent is configured to at least partially maintain a compressed state when a radially compressive force is removed from the inner stent after being radially compressed from an expanded state to a compressed state under the action of the radially compressive force. The outer stent of a prosthetic valve fixation device according to the present application may at least partially self-restore in diameter while extending distally from the interventional delivery instrument during implantation, while the inner stent may at least partially remain in a compressed diameter, thereby leaving space between the two that captures 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 the compressed state. After capturing the leaflets of the native valve 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 a balloon or the like disposed inside the inner stent, thereby clamping 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 chromium alloy or stainless steel. Stents made from these materials are capable of maintaining the dimensions of a compressed state after being compressed and the compressive force removed, and are capable of recovering the dimensions of an expanded state upon application of an expansion force.

Another aspect of the present application relates to a valve replacement device comprising a prosthetic valve fixation device according to any of the embodiments described above and a prosthetic valve. 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

Prosthetic valve fixation devices and valve replacement devices according to various 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 materials such as porcine pericardium, bovine pericardium, etc., or biocompatible synthetic materials and functioning to open and close with the contraction and relaxation of the corresponding ventricles, atria, of the heart, without including means to secure the structure to the site of implantation; 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 periphery of the "prosthetic valve" may be fixed to the inside of the "prosthetic valve fixation device".

It is to be understood that the drawings are solely for purposes of illustration and explanation and are not intended to limit the scope of the present disclosure in any way. Further, the drawings are merely schematic representations, not necessarily to scale, of the positions and combinations of elements, and 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 a valve replacement device according to an embodiment of the present application retracted within an interventional delivery instrument;

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

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

figure 5B is a schematic bottom view illustrating a valve replacement device during a process of capturing leaflets according to one embodiment of the present application;

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

fig. 6A is a schematic perspective view illustrating a valve replacement device during a process of clamping leaflets according to an embodiment of the present application;

figure 6B is a schematic bottom view illustrating a valve replacement device during a leaflet coaptation procedure according to one embodiment of the present application;

figure 6C is a schematic bottom view illustrating a valve replacement device according to another embodiment of the present application during a process of gripping leaflets;

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

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

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

In some of these figures, the illustration of some components may be omitted for clarity of illustration or to avoid obscuring the like, and should not be understood to mean that corresponding components are not included in the illustrated embodiments.

Detailed Description

Prosthetic valve fixation devices and valve replacement devices incorporating the same, and their implantation processes, 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 in 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 device (such as a sheath, etc.) or component thereof is farther from an operator (such as a physician), such as the lower left of each schematic perspective view 1, 2 and the lower right of each schematic perspective view 3, 4, 5A, 6A, 7A, particularly for aortic valves, indicating a direction pointing from the aorta to the left ventricle perpendicular to the aortic valve plane, while the term "proximal" refers to a direction in which a prosthetic valve fixation device, a valve replacement device, an implantation device, an interventional delivery device (such as a sheath, etc.), etc., or component thereof is closer to an operator (such as a physician), such as the upper right of each schematic perspective view 1, 2 and the upper left of each schematic perspective view 3, 4, 5A, 6A, 7A, particularly for aortic valves, indicating the direction pointing from the left ventricle to the aorta perpendicular to the aortic valve plane). 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 stent, etc., or components thereof, is the end that enters the patient first, while the "proximal end" is the other end that enters the patient later. In the present application, "valve" is used interchangeably with other valves, such as aortic valves, pulmonary valves, etc., because prosthetic valve fixation devices and valve replacement devices according to the present application can be adapted to repair a variety of valves, simply by adjusting the specific configuration of the inner and outer stents according to the number, size, morphology and treatment requirements of the valve leaflets being treated. Thus, while the structure, function, and function and beneficial effects of the prosthetic valve fixation device and valve replacement device according to the present application are explained below for the case of treatment of aortic valve bileafled malformations (hereinafter used interchangeably with "bileaflet valve"), it is to be understood that these components and their function and beneficial effects 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 can include an outer stent 120 and an inner stent 140, the outer stent 120 being radially nested outside the inner stent 140. The inner stent 140 can 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 fixture 100 between the open proximal end 146 and the open distal end 142. Outer bolster 120 may have a three-dimensional annular 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 fixture 100 to form an annular shape in three-dimensional space to facilitate capturing and gripping the leaflets of the native valve, as will be described in more detail below with reference to the figures. In other words, outer cradle 120 may be annular end-to-end in a bottom view as viewed along the longitudinal axis, and may present a non-planar structure that is convex distally and/or proximally along the longitudinal axis in a side view as viewed 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 support on the annulus inner circumference of the native valve.

In some embodiments, outer support 120 may be fixedly connected to inner support 140 in an axial direction along the longitudinal axis. In this case, there will not be any significant relative axial movement between the outer stent 120 and the inner stent 140 when changing between a collapsed state (e.g., radially compressed for collapsed accommodation within the interventional delivery device) and a deployed state (e.g., deployed after being extended from within the interventional delivery device in preparation for capturing leaflets). Accordingly, the interventional delivery device does not need to 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 process and avoiding the increase of the delivery outer diameter from affecting the pushing efficiency. In addition, this avoids relative axial position errors or misalignments that may be introduced when outer stent 120 is moved axially relative to inner stent 140, thus reducing the risk of implant failure. In some embodiments, outer stent 120 may be axially fixedly stitched or tied to inner stent 140 by a thin wire, such as nitinol, or may be completely fixedly connected to 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 when subjected to a radially compressive force. Still referring to fig. 2, in some embodiments, because outer stent 120 may be fixedly connected to inner stent 140 in an axial direction along the longitudinal axis, the relative axial position between outer stent 120 and inner stent 140 does not change in the collapsed state as compared to the expanded state shown in fig. 1. The application of the radially compressive force to the prosthetic valve fixation device 100 can be performed by any apparatus known or yet to be developed in the art, such as by crimping the apparatus or loading tool, for retraction into an interventional delivery instrument, such as a sheath, as shown in fig. 3. In some embodiments, the inner stent 140 in the collapsed state may be circumferentially 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 fixture 100 is collapsed to the collapsed state shown in fig. 2 under the action of the radial compressive force, the outer stent 120 can self-expand to at least partially return to the original radial dimension in the expanded state shown in fig. 1 when the radial compressive force is removed from the prosthetic valve fixture 100 (e.g., when the prosthetic valve fixture 100 is extended distally from an interventional delivery instrument such as a sheath during implantation). By virtue of the self-expanding nature, the outer stent 120 of a prosthetic valve fixation device 100 according to the present application can at least partially self-restore its diameter when extended from the distal end of an interventional delivery instrument during implantation, and portions of the outer stent 120 can at least partially restore the original shape in the deployed state. Thus, the circumferential angle of the prosthetic valve fixation device 100 need only be adjusted before capturing the leaflets of the native valve, rather than having to use an expansion 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 required to be performed during the implantation procedure and shortens the procedure time, which may improve the prognosis of the patient.

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

In some embodiments, the three-dimensional annular shape of the outer stent 120 can comprise at least two distal raised portions 122, each distal raised portion 122 projecting distally along the longitudinal axis of the prosthetic valve fixation device 100 in a side view in a radial direction. The distal raised portions 122 serve to capture and clamp the respective leaflets of the native valve between themselves and the inner stent 140. During the implantation procedure, outer stent 120 can nest the leaflets of the native valve outside in a distal direction from the proximal to the distal. The distal raised portion 122 may face the leaflets in a distal direction so as to be captured within the space between the outer stent 120 and the inner stent 140 in the collapsed state, as will be described in more detail below with reference to fig. 4-6C. In some embodiments, each distal raised portion 122 can have a "U" shape, wherein a curvilinear base of the "U" shape extends 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 can be connected together at a respective proximal connecting portion 124 to form a complete three-dimensional annular shape of outer bolster 120. In some embodiments, as shown in fig. 1, each proximal connecting portion 124 may be loosely or tightly stitched/tied by a wire, or fixedly connected to the outer periphery of inner stent 140 by welding, soldering, or the like, such that outer stent 120 is fixedly connected to inner stent 140 in an axial direction along the longitudinal axis.

Additionally, in some embodiments, the at least two distal raised portions 122 of the three-dimensional annular shape of outer bolster 120 described above may include 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 can 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 treatment of valve diseases having two leaflets, such as treatment of simple regurgitant aortic valve bilobalization malformations without stenosis and calcification. Even if the annulus of the bileafled aortic valve of the diseased patient is unable to effect installation of the prosthetic valve fixation device 100 by radial support alone due to the soft tissue, 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 external bolster 120 constitutes a portion of tubular sidewall 144 in the deployed state. In other words, in a bottom view from the distal side to the proximal side as shown in, for example, fig. 5B, 5C, 6B, 6C, 7B, and 7C, the outer stent 120 in the deployed state takes a circular ring shape. By way of example, a cylindrical tube of material may be cut by a laser cutting or like process to produce the three-dimensional annular shape of outer cradle 120. Alternatively, when the annulus inner wall of the native valve deviates significantly from a cylindrical shape, a cylinder of material that mimics the native annulus shape may also be cut to make the three-dimensional annular shape of outer stent 120. In this case, when the prosthetic valve fixation device 100 is implanted with the longitudinal axis perpendicular to the native valve plane, the three-dimensional annular shape of the outer stent 120 in the deployed state may generally best match the shape of the annulus inner wall of the native valve, as will be described in more detail below with reference to fig. 7A.

Because there is no need to rely on radial support force to support on the inner 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 non-stenotic, non-calcified valve diseases, even if the native valve annulus is not able to provide sufficient reaction force for radial support of the prosthetic valve fixation device 100 due to the soft tissue. Accordingly, in some embodiments, the outer stent 120 in the deployed state may have an outer diameter that is no greater than the inner diameter of the annulus of the native valve, and thus may not substantially create radially outward support forces after implantation to avoid any additional damage to the annulus. In other words, after implantation, the outer stent 120 may have an outer diameter just equal to the inner diameter of the annulus of the native valve to fit around the inner circumference of the annulus, but without requiring a radially expanding force on the annulus, or with only a minor radially expanding force; alternatively, the outer stent 120 may also have an outer diameter that is 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 outer bolster 120 should not be too small to create paravalvular leakage. Preferably, the outer stent 120 in the deployed state has an outer diameter of 15mm to 30mm, so that the outer diameter of the prosthetic valve holder 100 of the embodiment of the present application is smaller than that of the prosthetic valve holder required in the prior art when the inner diameter of the annulus of the native valve is fixed.

In some embodiments, the tubular sidewall 144 of the inner stent 140 may have a lattice-like structure to facilitate increased radial compressibility, which may be more easily collapsed within an interventional delivery device with a smaller delivery outer diameter (profile). In some embodiments, the grid-like structure may be composed of a polygonal mesh such as a hexagonal mesh, a quadrangular mesh, or a combination thereof in the expanded state. It will be appreciated that the inner stent 140 formed of hexagonal cells and quadrilateral cells is more easily compressed to a smaller radial dimension or expanded to return to the original radial dimension than a stably shaped cell such as a triangular cell.

In some embodiments, the inner stent 140 may be configured to at least partially maintain a compressed state when a radial compressive force is removed from the inner stent after being radially compressed from an expanded state to the compressed state under the action 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 the original radial dimensions 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-restore to the original diameter in the deployed state, while the inner stent 140 may at least partially remain in the compressed radial dimension without spontaneously fully expanding to restore to the original radial dimension in the deployed state, thereby leaving space between the inner and outer stents 140, 120 to capture the leaflets of the native valve, as will be described in more detail below with reference to fig. 4-5C.

In some embodiments, the inner stent 140 may be configured such that, when in a compressed state, the inner stent 140 may radially expand from the compressed state to an original radial dimension of the expanded state upon application of a radially outward force on an inner surface of the inner stent 140. After capturing the leaflets of the native valve 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 the like disposed inside the inner stent 140, thereby clamping the leaflets therebetween, as will be described in more detail below with reference to fig. 6A-6C.

In some embodiments, inner support 140 may be made of a non-shape memory material. In other words, the material from which inner stent 140 is fabricated may be free of self-expanding properties, shape memory properties, or superelasticity. In some embodiments, the material may be cobalt chromium alloy or stainless steel, or a more rigid material with biocompatibility and durability that is currently available or yet to be developed in the art. It will be appreciated that inner stents 140 fabricated from these materials are capable of at least partially maintaining the radial dimension in the compressed state after being compressed and the compressive force removed, and are capable of restoring the radial dimension in the expanded state upon application of an expansion force.

In some embodiments, inner stent 140 and/or outer stent 120 may be coated with a biocompatible coating, such as polyethylene terephthalate (PET), to improve biocompatibility, reduce rejection, 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 in 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 collectively form an integral part of the function of the prosthetic valve with the prosthetic valve fixation device 100 and the annulus of the native valve. In some embodiments, the prosthetic valve may have, for example, three leaflets and be sutured to the inner surface of the inner stent 140 at several points around its periphery or secured to the inner surface of the inner stent 140 with a structure such as a pedestal (not shown). In some embodiments, the prosthetic valve may be made of a membrane of a material that is currently or yet to be developed in the art, such as a natural material, e.g., porcine pericardium, bovine pericardium, or a synthetic material with biocompatibility and durability.

With reference to fig. 3-7C, the implantation process of a valve replacement device comprising a prosthetic valve fixation device 100 according to the present application and a prosthetic valve is explained below. Although in these drawings and the following description, reference is made to the treatment of aortic valve bileaflet malformations, and prosthetic valve fixation device 100 is illustrated and described as including a pair of distal raised portions 122, prosthetic valve fixation devices 100 and valve replacement devices 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 in valves having three leaflets, such as non-bileaflet malformed aortic valves, pulmonary valves, tricuspid valves, and the like. Additionally, in these figures, the illustration of the prosthetic valve may be omitted for clarity of illustration and to avoid obscuring, but rather only the prosthetic valve fixation device 100 is shown, which is not meant to indicate that the prosthetic valve is not included in these implantation procedures.

Fig. 3 is a schematic perspective view illustrating a valve replacement device according to an embodiment of the present application retracted within an interventional delivery instrument 200. In the collapsed state shown in fig. 3, the valve replacement device is delivered to the vicinity of the aortic valve location by a minimally invasive surgical procedure, such as femoral artery intervention, using 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, both the inner stent 140 and the outer stent 120 of the prosthetic valve fixation device 100 may 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 collapsed inside the inner stent 140 at this time. In addition, the collapsed inner stent 140 may be sleeved inside with an expansion device (not shown in fig. 3), such as a balloon, to expand the inner stent 140 without self-expanding properties to return to the radial dimension of the deployed 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 guide wire (not shown) to deliver the valve replacement device and sheath to the target site.

Fig. 4 is a schematic perspective view illustrating a valve replacement device according to an embodiment of the present application extending from an interventional delivery instrument 200. As an example, the valve replacement device may be advanced out of the distal end of the sheath by distal movement of the balloon catheter relative to the sheath after the target location is reached. It will be appreciated that at this point the entirety of the valve replacement device 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 time, under the self-expanding property of the shape memory material or superelastic material of the outer stent 120, the outer stent 120 self-expands to at least partially return to the original radial dimension in the deployed state, while the inner stent 140 still at least partially maintains the contracted radial dimension in the contracted state. In this case, a pair of distal raised portions 122 of the outer stent 120 of the prosthetic valve fixation device 100 may be respectively aligned circumferentially with a pair of native leaflets of the bivalvular malformed aortic valve, 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 process of capturing leaflets according to an embodiment of the present application. As shown in fig. 5A, after completion of the extension and alignment operations described above with reference to fig. 4, the valve replacement device is moved distally (in the direction from the aorta to the left ventricle, for example, with the aortic valve) until the distal ends of the outer stent 120 and/or the inner stent 140 substantially abut the proximal side of the aortic valve (i.e., the aortic side) to nest the pair of native leaflets in the space between the pair of distal raised portions 122 of the deployed outer stent 120 and the collapsed 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 the radial supporting force between the outer stent 120 and the annulus 300 to fix the prosthetic valve fixation device 100.

Fig. 5B is a schematic bottom view (view from left ventricle toward aorta, for example, with aortic valve) illustrating a valve replacement device according to one embodiment of the present application during a leaflet capture procedure. As shown in fig. 5B, the inner stent 140 is now fitted over the outer circumference of an expansion device 400, such as a balloon, along with the prosthetic valve 500, and the outer stent 120 has self-expanded to a radial dimension that is close to or equal to the inner diameter of the valve 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 tied/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 raised portion 122 of the outer stent 120 and the inner stent 140 for accommodating 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 be affixed to the inside of the inner stent 140.

Fig. 5C is a schematic bottom view (a view from the left ventricle looking in the direction of the aorta, taking the aortic valve as an example) illustrating a valve replacement device according to another embodiment of the present application during the process of capturing the leaflets. In contrast to the embodiment shown in fig. 5B, the outer stent 120 in the embodiment shown in fig. 5C may be fastened to the inner stent 140 at the pair of proximal connecting portions 124 by, for example, welding, soldering, or wire-bonding/sewing. Thus, when outer stent 120 is extended out of the sheath and self-expands, inner stent 140 is also at least partially expanded in a direction corresponding to the pair of proximal connecting portions 124 of outer stent 120. In contrast, the inner stent 140 still at least partially maintains 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 radial space of d2 between it and the distal raised portions 122 of the outer stent 120 for accommodating the leaflets capturing the native valve. It will be appreciated that in this case, the prosthetic valve 500 also at least partially deploys 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 on the balloon that has not yet been inflated.

Fig. 6A is a schematic perspective view illustrating a valve replacement device during a process of clamping leaflets according to an embodiment of the present application, with illustration of a prosthetic valve omitted to illustrate placement of a balloon. After the pair of native leaflets are captured and positioned in the space between the pair of distal raised portions 122 of the expanded outer stent 120 and the contracted inner stent 140, as shown in fig. 6A, an expansion device 400, such as a balloon, sheathed within the inner stent 140 is radially expanded, radially expanding the inner stent 140 to a radial dimension at least partially restoring the expanded state to securely 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 the open state as a result of being clamped, and no longer function as an open and close valve, and the valve replacement device has been fixed in the native valve position by virtue of clamping the native leaflets v1, v 2.

Fig. 6B is a schematic bottom view (view from left ventricle to aorta, for example, of an aortic valve) illustrating a valve replacement device according to one embodiment of the present application during a leaflet clipping procedure. In the embodiment shown in fig. 6B, the outer stent 120 may be loosely tied/sewn with wires at a pair of proximal connecting portions 124 to corresponding positions of the inner stent 140, corresponding to the embodiment shown in fig. 5B. As shown in fig. 6B, during the leaflet clipping procedure shown in fig. 6A, an expansion device 400, such as a balloon, is expanded 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 against the inner wall of the inner stent 140 by the expansion device 400. After this procedure, the prosthetic valve fixation device 100, together with the carried prosthetic valve 500, has been fixed at the position of the native valve by clamping the native leaflets v1, v 2.

Fig. 6C is a schematic bottom view (view from left ventricle to aorta, for example, of an aortic valve) illustrating a valve replacement device according to another embodiment of the present application during a process of clamping leaflets. 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 fastened to the inner stent 140 at the pair of proximal connecting portions 124 by, for example, welding, or wire-tight binding/sewing. Similarly, after the expansion of the inner stent 140 using the expansion device 400, the radial space between the inner stent 140 and the pair of distal convex 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 convex portions 122.

Fig. 7A is a schematic perspective view illustrating a valve replacement device according to an embodiment of the present application after implantation is completed, with illustration of the prosthetic valve omitted for clarity in showing the inner stent 140 and the annulus 300. After grasping the native leaflets v1, v2, the inflation device 400, such as a balloon, is deflated 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 a normal operating state by abutting against the inner wall of the inner stent 140, thereby replacing the function of the native aortic valve, i.e., opening and closing with the contraction and relaxation of the left ventricle, respectively.

Fig. 7B is a schematic bottom view (view from left ventricle toward aorta, for example, with an aortic valve) illustrating a valve replacement device according to one embodiment of the present application after implantation is complete. In the embodiment shown in fig. 7B, the outer stent 120 may be loosely tied/sewn to the corresponding position of the inner stent 140 with a wire at a pair of proximal connecting portions 124, corresponding to the embodiment shown in fig. 5B, 6B. After implantation is complete and the devices 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 (view from the left ventricle toward the aorta, for example, of an aortic valve) illustrating a valve replacement device according to another embodiment of the present application after implantation is complete. 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 fastened to the inner stent 140 at the pair of proximal connecting portions 124 by, for example, welding, soldering, or wire-tight binding/sewing.

As shown in fig. 5B, 5C, 6B, 6C, 7B, and 7C, since the prosthetic valve fixing device 100 according to the present application does not rely on a radial supporting force between the outer stent 120 and the annulus 300 to fix the prosthetic valve, the outer diameter of the outer stent 120 after implantation may not be greater than the inner diameter of the annulus 300 of the native valve. In other words, after implantation is complete, the outer stent 120 may have an outer diameter just equal to the inner diameter of the native valve's annulus 300 to fit around the inner circumference of the annulus 300 without the need to apply high radial expansion forces to the annulus 300. So, need not to use the very high support of rigidity and radial holding power to realize the firm location of prosthetic valve fixing device 100, can make prosthetic valve fixing device 100 remain better compliance and adherence simultaneously to when avoiding shifting, reduce the valve perivalvular leakage and harm risks such as valve ring. Alternatively, the outer stent 120 may also have an outer diameter that is slightly larger or slightly smaller than the inner diameter of the native valve's annulus 300 after implantation. Preferably, the outer diameter of outer stent 120 after implantation ranges from 15mm to 30 mm. In addition, as shown in fig. 3-7C, which illustrate the implantation procedure, no axial (i.e., distal or proximal) relative movement occurs between inner stent 140 and 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 outer stent 120 and inner stent 140.

It will be understood that various modifications may be made to the disclosed apparatus. Accordingly, the above description should not be construed as limiting, but merely as exemplifications of embodiments of the disclosure. Other modifications will occur to those skilled in the art within the scope and spirit of the disclosure. For example, any and all features of one described embodiment may be incorporated into another embodiment as appropriate, and the benefits of such features 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 leaflets 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 fitted over a radially outer side of the inner bracket;

wherein the inner stent and the outer stent are configured to clamp each leaflet of the native valve between the inner stent and the outer stent to secure the prosthetic valve fixation device over the leaflets of the native valve, and

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 a compressed state under the action of the radial compressive force.

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

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 convex portions, each of the at least two distal convex portions for clamping a respective leaflet of the native valve between the respective distal convex portion and the inner stent.

7. The prosthetic valve fixation device of claim 6, wherein each of the at least two distal raised portions has a "U" shape.

8. The prosthetic valve fixation device of claim 6, wherein each adjacent pair of the at least two distal raised portions are connected together at a proximal connecting 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 tying, welding, or welding.

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

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

13. The prosthetic valve fixation device of claim 12, wherein the inner stent is configured to radially expand from the compressed state to the deployed 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 chromium or stainless steel.

15. A valve replacement device, comprising:

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

the artificial valve is a valve-shaped artificial valve,

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

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