Transcatheter mitral valve stent
By adopting an integrated valve stent body, anchoring needle and clamping ring structure in the transcatheter mitral valve stent, it directly anchors to the mitral valve annulus and clamps the anterior leaflet of the mitral valve, the complex and risky anchoring process in the prior art is solved, and the surgical steps are simplified and time is shortened.
Patent Information
- Application Number
- CN202420928072.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2034-04-30
AI Technical Summary
In the prior art, transcatheter mitral valve stents have the risk of shedding, puncture of the heart and causing embolism during anchoring, and the operation is complicated, increasing the surgical steps and time.
The integrated structure of the valve stent body, anchoring needle and clamping ring is adopted. The anchoring needle is directly anchored to the mitral valve annulus. The clamping ring clamps the anterior leaflet of the mitral valve to achieve synchronization of the stent anchoring and release fixation process.
Reduces surgical steps and complexity, shortens surgical time, avoids the risks of valve migration and perival leakage, and improves the stability and sealing of the valve stent.
Smart Images
Figure CN222828698U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of heart valve implantable medical devices, and in particular to a transcatheter mitral valve stent. Background Art
[0002] Transcatheter mitral valve replacement for mitral regurgitation requires the valve to have stable anchoring and tight sealing to prevent valve displacement, paravalvular leakage, and thrombosis. The design of the transcatheter mitral valve must take into account anatomical structure and pathological changes: the mitral valve ring is a non-continuous structure, and its shape changes with the cardiac cycle, which means that the implanted valve will not be evenly stressed; the subvalvular structure of the mitral valve is complex, including multiple groups of chordae tendineae, papillary muscles, plus the endocardium and myocardium of the left atrium and left ventricle, and the aortic-mitral curtain, which should be regarded as a mitral valve complex. The complex structure will increase the difficulty of transcatheter surgery and the difficulty of anchoring; the degree of valve calcification in mitral regurgitation is lighter than that of aortic stenosis, and it cannot provide sufficient support. These can hinder the fixation and sealing of the valve and increase the risk of valve migration and paravalvular leakage.
[0003] Valve anchoring is an important link and factor in the normal functioning of transcatheter valves. Currently, the transcatheter mitral valve anchoring mechanisms mainly include the following categories: capturing the valve leaflets and annulus; apical traction fixation; filling the atrium; radial force support; and supra-annular and ventricular anchoring.
[0004] In the prior art, transcatheter mitral valve stents often use external anchoring devices to anchor the valve stents, which may result in the following problems or shortcomings:
[0005] (1) The anchoring device needs to be pre-installed on the valve stent or implanted into the valve stent using a special instrument. The anchoring device may fall off into the heart cavity, puncture the heart, and cause embolism.
[0006] (2) The anchoring process is not synchronized with the release of the valve stent. The process of anchoring the valve stent is to stimulate and pull the anchoring device or implant the anchoring device with a special instrument after the stent expands and releases into place, so as to achieve the purpose of fixing the valve stent. This operation method increases the number of surgical steps, increases the complexity of the operation, and prolongs the operation time. Summary of the invention
[0007] In order to solve the existing technical problems, the present application provides a transcatheter mitral valve stent that avoids the problems caused by using an external anchoring device to anchor the valve stent.
[0008] To achieve the above purpose, the technical solution of the embodiment of the present application is implemented as follows:
[0009] An embodiment of the present application provides a transcatheter mitral valve stent, comprising a valve stent body, an anchoring needle for anchoring to the mitral valve ring, and a clamping ring for clamping the anterior leaflet of the mitral valve, the valve stent body being a compressible mesh stent and comprising a stent body ventricular portion arranged along the longitudinal axis and a stent body atrial portion arranged above the stent body ventricular portion; the anchoring needle is located at the portion of the stent body atrial portion that contacts the atrial myocardium on the surface of the posterior valve ring of the mitral valve and can puncture into the myocardium while being parallel to the longitudinal axis of the stent body ventricular portion; the clamping ring is arranged at the front of the stent body ventricular portion.
[0010] In one embodiment, the anchoring needle and the valve stent body are an integral structure, and the anchoring needle is parallel to the longitudinal axis of the ventricular portion of the stent body or points to the mitral valve annulus at a certain angle.
[0011] In one embodiment, the anchoring needle includes a plurality of anchoring needle segments extending downwardly from the atrial portion of the stent body.
[0012] In one embodiment, each anchoring needle segment is in the shape of a semi-parabola, a quarter arc, or a shape in which the starting segment points to the mitral valve annulus at a certain angle and the posterior puncture segment is parallel to the longitudinal axis.
[0013] In one embodiment, the valve stent body is made of metal tube, and the number of anchoring needle segments in the anchoring needle matches the number of circumferential metal tube grids in the portion where the atrial portion of the stent body contacts the atrial myocardium on the posterior annular surface of the mitral valve.
[0014] In one embodiment, the height of the clamping ring does not exceed the average width of the left ventricular outflow tract and does not exceed the average height of the anterior leaflet of the mitral valve. In one embodiment, the clamping ring and the valve stent body are an integrated structure, and the clamping ring arches upward from the lower end of the ventricular portion of the stent body.
[0015] In one embodiment, the clamping ring has one ring portion, or has two or more ring portions connected end to end; each of the ring portions is in an arc shape.
[0016] In one embodiment, the end of each of the ring portions has a connection portion connected to the lower end of the ventricular portion of the stent body.
[0017] In one embodiment, the transcatheter mitral valve stent is made of a metal tube, and the anchoring needle and the clamping ring are integrally formed with the valve stent body.
[0018] The transcatheter mitral valve stent of the present application has at least the following beneficial effects: in the transcatheter mitral valve stent of the present application, a structure of a valve stent body, an anchoring needle, and a clamping ring is adopted, so that during the overall release process of the valve stent, the anchoring needle can directly anchor the valve stent to the mitral valve ring and the clamping ring can clamp the anterior leaflet of the mitral valve without the need for prior assembly or additional implantation, thereby achieving synchronization of the stent anchoring and stent release and fixation processes, reducing surgical steps, reducing surgical complexity, and shortening surgical time. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the structure of a transcatheter mitral valve stent installed with an embodiment of the present application;
[0020] Figure 2 for Figure 1 A schematic diagram of the side structure of the valve stent body;
[0021] Figure 3 It is a schematic diagram of the structure of a valve stent body with an O-shaped cross section in the ventricular portion of the stent body viewed from above;
[0022] Figure 4 It is a schematic diagram of the structure of a valve stent body with a D-shaped cross section in the ventricular portion of the stent body viewed from above;
[0023] Figure 5 for Figure 1 Schematic diagram of the structure of the anchoring needle;
[0024] Figure 6 for Figure 5 Schematic diagram of the enlarged structure of the anchoring needle segment;
[0025] Figure 7 is a schematic structural diagram of an anchoring needle according to another embodiment;
[0026] Figure 8 for Figure 7 Magnified view of the anchoring needle segment in;
[0027] Fig. 9 for Figure 1 An enlarged structural schematic diagram of the clamping ring in FIG.
[0028] Fig.10 is a schematic structural diagram of a clamping ring according to another embodiment;
[0029] Fig.11 It is a schematic diagram of a top view of a transcatheter mitral valve stent using different anchoring needles and different clamping rings when the ventricular portion of the stent body is an O-shaped cross section;
[0030] Fig.12It is a schematic diagram of the top view of the structure of a transcatheter mitral valve stent that uses different anchoring needles and different clamping rings when the ventricular portion of the stent body is a D-shaped cross-section.
[0031] The components in the figure are labeled as follows:
[0032] A valve stent body 10 (including a stent body atrial portion 11 and a stent body ventricular portion 12);
[0033] Anchoring needle 20 (including anchoring needle segment 21);
[0034] A clamping ring 30 (including a ring portion 31 and a connecting portion 32);
[0035] Transcatheter mitral valve stent 100 . DETAILED DESCRIPTION
[0036] The technical solution of the present application is further elaborated in detail below in conjunction with the accompanying drawings and specific embodiments of the specification.
[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit the implementation of this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0038] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating positions or positional relationships, are based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the description of the present application, unless otherwise specified, "multiple" means two or more.
[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0040] The transcatheter mitral valve stent of the present application is used for transcatheter mitral valve replacement, and the transcatheter mitral valve is tightly fixed on the valve ring through an anchoring needle, thereby avoiding valve migration and paravalvular leakage. The anchoring mechanism of the transcatheter mitral valve stent of the present application is direct, simple and effective. The valve stent is directly and firmly anchored in the heart cavity, which can achieve the synchronization of the valve stent and the heart movement, increase the fit of the valve stent with the endocardium and the valve leaflets, and thus prevent valve displacement, paravalvular leakage and thrombosis.
[0041] See also Figure 1 The transcatheter mitral valve stent 100 of one embodiment of the present application includes a valve stent body 10, and an anchoring needle 20 and a clamping ring 30 arranged on the valve stent body 10. The anchoring needle 20 is used to directly anchor to the mitral valve ring, and the clamping ring 30 is used to clamp the anterior leaflet of the mitral valve. The transcatheter mitral valve stent 100 can be made of a metal tube (such as a nickel-titanium memory alloy tube) by laser engraving, and the valve stent body 10, the anchoring needle 20 and the clamping ring 30 are an integrated structure.
[0042] Please refer to Figure 2 The valve stent body 10 is a compressible and expandable mesh stent made of a metal tube (such as a nickel-titanium memory alloy tube), which can be divided into an upper stent body atrial part 11 and a stent body ventricular part 12 arranged along the longitudinal axis. The stent body atrial part 11 is high in front and low in back ( Figure 2 The low asymmetric shape (center right) Figure 2 The left side of the atrial part 11 of the middle stent body is higher than the right side. The front part of the atrial part 11 of the stent body is the part that contacts the anterior leaflet of the mitral valve, and forms an angle α with the ventricular part 12 of the stent body; the rear part of the atrial part 11 of the stent body is the part that contacts the left atrial endocardium on the posterior valve ring of the mitral valve, and forms an angle β with the ventricular part 12 of the stent body, and the angle α is greater than the angle β. The cross section of the ventricular part 12 of the stent body perpendicular to the longitudinal axis is O-shaped (such as Figure 3 As shown), D-shaped (as Figure 4 as shown) or other shapes that can adapt to the mitral valve orifice.
[0043] Please refer to Figure 5 and Figure 6 The anchoring needle 20 is located at the rear of the atrial part 11 of the stent body and contacts the atrial muscle on the surface of the posterior mitral valve ring. This part contacts the rear of the left atrium and is directly anchored to the mitral valve ring. The anchoring needle 20 is an integrated structure with the valve stent body 10, parallel to the longitudinal axis of the ventricular part 12 of the stent body or at a certain angle to the mitral valve ring, and maintains a certain distance from the ventricular part 12 of the stent body.
[0044] The anchoring needle 20 includes a plurality of anchoring needle segments 21 extending downward from the atrial portion 11 of the stent body. Each anchoring needle segment 21 directly penetrates the endocardium, atrial muscle, mitral valve ring, and part of the ventricular muscle above the mitral valve ring on the atrial surface, so that the valve stent body 10 is directly fixed on the mitral valve ring, and the valve stent body 10 is pulled toward the posterior leaflet of the mitral valve. The valve stent body 10 is tightly fitted to the left atrial endocardium and the posterior leaflet of the mitral valve.
[0045] The number of anchoring needle segments 21 in the anchoring needle 20 matches the number of circumferential metal tube (e.g., nickel-titanium memory alloy tube) grids in the portion of the rear portion of the atrial portion 11 of the stent body that contacts the atrial muscle on the posterior annular surface of the mitral valve. In the illustrated embodiment, each anchoring needle segment 21 is in the shape of a semi-parabola, a quarter arc, or other shapes, and all are parallel to the longitudinal axis of the mitral stent.
[0046] See also Figure 7 and Figure 8 Each anchoring needle segment 21 of the anchoring needle 20 may also be in a shape in which the starting segment points to the mitral valve ring at a certain angle and the posterior puncture segment is parallel to the longitudinal axis of the ventricular portion 12 of the stent body.
[0047] That is, the anchor needle 20 only needs to be able to penetrate into the myocardium while maintaining parallelism with the longitudinal axis of the ventricular portion 12 of the stent body.
[0048] Please refer to Fig. 9 and Fig.10 The clamping ring 30 is located in the front part of the ventricular part 12 of the stent body, and can clamp the anterior leaflet of the mitral valve and part or all of the tendons attached to the anterior leaflet of the mitral valve, so that the valve stent body 10 and the anterior leaflet of the mitral valve fit tightly. The clamping ring 30 and the valve stent body 10 are an integrated structure. The clamping ring 30 arches upward from the lower end of the ventricular part 12 of the stent body, and its height does not exceed the average width of the left ventricular outflow tract, nor does it exceed the average height of the anterior leaflet of the mitral valve. The clamping ring 30 may have a ring portion 31 (such as Fig. 9 ), or having two or more end-to-end ring portions 32 (as shown in Fig.10 Each ring portion 31 is in a shape with a curvature such as a semi-circular shape, a semi-elliptical shape, a semi-circular shape, a semi-arch shape, etc. The end of each ring portion 31 has a connecting portion 32 for connecting to the lower end of the ventricular portion 12 of the stent body.
[0049] See also Fig.11 , which is an example of different embodiments of the transcatheter mitral valve stent 100 when the cross-section of the ventricular portion 12 of the stent body perpendicular to the longitudinal axis is O-shaped. Fig.11 (a) is to adopt Figure 5 The anchor needle 20 shown in FIG. Fig. 9 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 shown in FIG.
[0050] Fig.11 (b) is to adopt Figure 5 The anchor needle 20 shown in FIG. Fig.10 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 shown in FIG. Fig.11 (c) is to adopt Figure 7 The anchor needle 20 shown in FIG. Fig. 9 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 shown in FIG. Fig.11 (d) is to adopt Figure 7 The anchor needle 20 shown in FIG. Fig.10 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 is shown in FIG.
[0051] See also Fig.12 , which is an example of different embodiments of the transcatheter mitral valve stent 100 when the cross-section of the ventricular portion 12 of the stent body perpendicular to the longitudinal axis is D-shaped. Fig.12 (a) is to adopt Figure 5 The anchor needle 20 shown in FIG. Fig. 9 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 shown in FIG.
[0052] Fig.12 (b) is to adopt Figure 5 The anchor needle 20 shown in FIG. Fig.10 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 shown in FIG. Fig.12 (c) is to adopt Figure 7 The anchor needle 20 shown in FIG. Fig. 9 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 shown in FIG. Fig.12 (d) is to adopt Figure 7 The anchor needle 20 shown in FIG. Fig.10 A top view of a transcatheter mitral valve stent 100 with a clamping ring 30 is shown in FIG.
[0053] In the above-mentioned transcatheter mitral valve stent 100, the anchoring needle 20 and the clamping ring 30 are both located on the valve stent body 10, and can be released and deployed synchronously with the valve stent body 10 without the need for prior assembly or additional implantation, thereby achieving synchronization of the stent anchoring and stent release and fixation processes, reducing surgical steps, reducing surgical complexity, and shortening surgical time.
[0054] In the above-mentioned transcatheter mitral valve stent 100, the anchoring needle 20 directly fixes the valve stent body 10 to the mitral valve ring, and pulls the valve stent toward the left atrial endocardium and the posterior leaflet of the mitral valve to make it fit tightly. The clamping ring clamps the anterior leaflet of the mitral valve and part or all of the tendons attached to the anterior leaflet of the mitral valve, so that the valve stent body 10 fits tightly with the anterior leaflet of the mitral valve. The tight fit between the valve stent body 10 and the anterior and posterior leaflets of the mitral valve can avoid or reduce blood leakage around the valve stent body 10, and can also avoid or reduce thrombosis and thrombus formation between the catheter mitral valve stent 100 and the native leaflets and the atrium.
[0055] The above-mentioned anchoring needle 20 directly fixes the valve stent body 10 to the mitral valve ring, and under the joint action of the radial supporting force of the valve stent body 10, the valve stent body 10 is closely fitted with the left atrial endocardium and the posterior leaflet of the mitral valve; the clamping ring 30 clamps the anterior leaflet of the mitral valve and part or all of the tendons attached to the anterior leaflet of the mitral valve; these two fixing structures firmly fix the valve stent body 10 in the heart cavity, so that the catheter mitral valve stent 100 can move synchronously with the heart, reducing the possibility of valve displacement.
[0056] When the transcatheter mitral valve stent 100 is compressed and loaded into the delivery sheath for transcatheter mitral valve replacement surgery, the transapical approach or the transfemoral vein approach can be adopted. Regardless of the transapical approach or the transfemoral vein approach, after the transcatheter mitral valve stent 100 compressed and loaded into the delivery sheath reaches the appropriate position of the left atrium and the left ventricle, as the valve stent body 10 is released, the anchoring needle 20 penetrates the endocardium, the atrial muscle, the mitral valve ring, and part of the ventricular muscle, so that the valve stent is directly fixed to the posterior valve ring of the mitral valve, and then the clamping ring 30 is released to clamp the anterior leaflet of the mitral valve.
[0057] Specifically, the release process and anchoring sequence of the transcatheter mitral valve stent 100 via the apical approach are as follows:
[0058] 1) The transcatheter mitral valve stent 100 is pushed out of the delivery sheath, the atrial portion 11 of the stent body is first released and partially self-expanded, and the anchoring needle 20 is also deployed accordingly. The release and deployment position of the atrial portion 11 of the stent body and the anchoring needle 20 is above the atrial muscle on the posterior annular surface of the mitral valve;
[0059] 2) The valve stent body 10 and the delivery sheath are withdrawn simultaneously until the anchoring needle 20 completely penetrates the atrial muscle and the rear part of the atrial part 11 of the stent body is closely attached to the endocardium;
[0060] 3) The delivery sheath is withdrawn while keeping the position of the valve stent body 10 unchanged. The clamping ring 30 withdraws from the delivery sheath and slowly rebounds to clamp the anterior leaflet of the mitral valve and part or all of the chordae tendineae, completing the release and anchoring process of the valve stent body 10.
[0061] Specifically, the release process and anchoring sequence of the transcatheter mitral valve stent 100 via the femoral vein approach are:
[0062] 1) The transcatheter mitral valve stent 100 is pushed out of the delivery sheath, and the ventricular portion 12 of the stent body is first released and partially self-expanded;
[0063] 2) Continue with the valve stent body 10, the atrial part 11 of the stent body is released, self-expanded and adjusted in position, and the anchoring needle 20 is also deployed accordingly, and the rear part of the atrial part 11 of the stent body and the anchoring needle 20 are positioned above the atrial muscle on the posterior annular surface of the mitral valve;
[0064] 3) Pushing the delivery sheath and the valve stent body 10 until the direct anchoring needle 20 completely penetrates the atrial muscle and the rear part of the atrial part 11 of the stent body is closely attached to the endocardium;
[0065] 4) Keeping the position of the valve stent body 10 unchanged, slowly release the clamping ring 30 to clamp the anterior leaflet of the mitral valve and part or all of the chordae tendineae, and then complete the release and anchoring process of the valve stent body 10.
[0066] In summary, the transcatheter mitral valve stent of the present application adopts an integrated structure of the valve stent body, anchoring needle, and clamping ring, so that the anchoring needle can directly anchor the valve stent on the mitral valve ring during the overall release of the valve stent, and the clamping ring can clamp the anterior leaflet of the mitral valve. After the mitral valve stent is anchored, under the joint action of the anchoring needle, the two clamping rings, and the radial support force of the valve stent body, the valve stent can be closely fitted to the endocardium to prevent the occurrence of paravalvular leakage and the formation of thrombus, and the synchronous movement of the valve stent and the heart can also be achieved.
[0067] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.
[0068] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A transcatheter mitral valve stent, characterized in that: It includes a valve stent body, an anchoring needle for anchoring to the mitral valve ring and a clamping ring for clamping the anterior leaflet of the mitral valve. The valve stent body is a compressible mesh stent and includes a ventricular part of the stent body arranged along the longitudinal axis and an atrial part of the stent body arranged above the ventricular part of the stent body; the anchoring needle is located at the part of the atrial part of the stent body that contacts the atrial muscle on the surface of the posterior valve ring of the mitral valve and can puncture into the myocardium while being parallel to the longitudinal axis of the ventricular part of the stent body; the clamping ring is arranged at the front of the ventricular part of the stent body.
2. The transcatheter mitral valve stent according to claim 1, characterized in that: The anchoring needle and the valve stent body are an integrated structure, and the anchoring needle is parallel to the longitudinal axis of the ventricular portion of the stent body or points to the mitral valve ring at a certain angle.
3. The transcatheter mitral valve stent according to claim 2, characterized in that: The anchoring needle includes a plurality of anchoring needle segments extending downward from the atrial portion of the stent body.
4. The transcatheter mitral valve stent according to claim 3, characterized in that: Each anchoring needle segment is in the shape of a semi-parabola, a quarter arc, or a shape in which the starting segment points to the mitral valve ring at a certain angle and the posterior puncture segment is parallel to the longitudinal axis.
5. The transcatheter mitral valve stent according to claim 3, characterized in that: The valve stent body is made of metal tubes, and the number of the anchoring needle segments in the anchoring needle matches the number of circumferential metal tube grids in the portion where the atrial portion of the stent body contacts the atrial myocardium on the surface of the posterior valve ring of the mitral valve.
6. The transcatheter mitral valve stent according to any one of claims 1 to 5, characterized in that: The height of the clamping ring does not exceed the average width of the left ventricular outflow tract and does not exceed the average height of the anterior leaflet of the mitral valve.
7. The transcatheter mitral valve stent according to claim 6, characterized in that: The clamping ring and the valve stent body are an integrated structure, and the clamping ring arches upward from the lower end of the ventricular portion of the stent body.
8. The transcatheter mitral valve stent according to claim 7, characterized in that: The clamping ring has one ring portion, or has two or more ring portions connected end to end; each of the ring portions is in an arc shape.
9. The transcatheter mitral valve stent according to claim 8, characterized in that: The end of each of the ring portions has a connection portion connected to the lower end of the ventricular portion of the stent body.
10. The transcatheter mitral valve stent according to claim 1, characterized in that: The transcatheter mitral valve stent is made of a metal tube, and the anchoring needle and the clamping ring are integrally formed with the valve stent body.