A heart valve stent and prosthesis thereof

Abstract

The present invention discloses a heart valve stent and its prosthesis, comprising a stent body, the stent body being composed of interconnected grid structure units, the stent body being axially divided into an inflow channel, a transition section, and an outflow channel connected in sequence, the stent also comprising a limiting structure connected to the stent body; the limiting structure being circumferentially distributed on the outflow channel or the transition section, the limiting structure comprising a first protrusion for limiting the movement of the stent from the inflow channel toward the outflow channel. The present invention provides a limiting structure on the outflow channel of the stent to prevent the stent from moving toward the outflow channel under the influence of blood flow. The inflow channel of the stent is configured to adapt to the shape of the native tissue, and an outer skirt is provided circumferentially on the outer side of the inflow channel where it mates with the native tissue, effectively preventing paravalvular leakage and preventing the valve from moving toward the inflow channel. In addition, the inflow channel of the stent of the present invention can be relatively short, effectively preventing atrioventricular conduction block, and the outflow channel can also be relatively short, reducing pressure on the aorta.

Description

Technical Field

[0001] The present invention relates to an interventional medical prosthesis, in particular to a heart valve stent and a prosthesis thereof. Background Art

[0002] With the advent of an aging society worldwide, aortic valve disease has become a common cardiovascular disease. The incidence in my country is 2%-5%, while in Europe and the United States it ranks third after coronary heart disease and hypertension. Every year, tens of thousands of patients could benefit from surgical aortic valve replacement. However, even in developed countries, a significant number of patients with severe aortic valve disease are unable to undergo surgical treatment due to advanced disease, advanced age, and multiple comorbidities. The emergence of percutaneous aortic valve prostheses and their continuous improvement in performance have undoubtedly brought hope to these patients, providing an effective treatment approach.

[0003] In 2002, Cribier et al. reported the first human transcatheter aortic valve replacement (TAVR). Since then, numerous scholars and physicians at home and abroad have conducted basic and clinical research on transcatheter aortic valve replacement (TAVR), achieving promising clinical results. Studies have shown that this new technology is safe and effective for patients who are unable to undergo surgical valve replacement or who are at high risk for surgical valve replacement. Compared with surgery, percutaneous aortic valve replacement (TAVR) does not require thoracotomy or extracorporeal circulation support. It is a treatment method with less trauma, fewer complications, faster postoperative recovery, less pain for patients, and is easily accepted. Although TAVR is often performed on high-risk patients, the 30-day survival rate after surgery is over 90%, and patients' hemodynamic indicators are significantly improved after surgery.

[0004] Existing TAVI valve prostheses are mostly deployed through self-expansion or balloon expansion. The principle is to compress the stent within a sheath, deliver it to the aortic valve via a delivery device through the femoral artery or apex of the heart, and then release it at the calcified annulus. The expanded stent then expands the calcified annulus and secures the entire artificial valve prosthesis, allowing the leaflets to open and begin functioning.

[0005] Judging from the clinical performance of aortic stents at home and abroad, there are some problems that need to be solved urgently.

[0006] 1. After the stent is released in the body, it is easy to shift;

[0007] 2. The ability of the valve prosthesis to prevent paravalvular leakage is limited;

[0008] 3. An inflow tract that is too long for a heart valve prosthesis can easily cause atrioventricular block. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a heart valve stent and prosthesis thereof, which can prevent the risk of the stent moving from the inflow tract to the outflow tract under the flushing of blood flow, and has a simple structure and is easy to implement.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is to provide a heart valve stent, including a stent body, the stent body is composed of interconnected grid structure units, and the stent body is divided into an inflow channel, a transition section and an outflow channel connected in sequence in the axial direction, wherein the stent also has a limiting structure connected to the stent body; the limiting structure is distributed on the outflow channel or the transition section along the circumferential direction, and the limiting structure has a first protrusion for limiting the movement of the stent from the inflow channel toward the outflow channel.

[0011] Furthermore, the limiting structure and the bracket body are manufactured separately and then assembled.

[0012] Furthermore, the first protrusion is an arc-shaped protrusion, a trapezoidal protrusion, a wavy protrusion or a sawtooth-shaped protrusion.

[0013] Furthermore, the area of ​​the grid structure unit located in the transition section on the bracket is larger than the area of ​​the grid structure unit of the inflow channel or the outflow channel.

[0014] Furthermore, the transition section has a concave structure away from the first protrusion.

[0015] Furthermore, the distance between the plane where the vertex of the first protrusion is located and the plane where the outflow channel port is located is 0-30 mm.

[0016] Furthermore, after the stent is released and expanded, the port of the outflow tract does not extend out of the sinus-tubular junction.

[0017] Furthermore, after the stent is released and expanded, the inflow channel has at least one contact position with native tissue above the valve annulus.

[0018] Furthermore, after the stent is released and expanded, the inflow channel is closely fitted with the native tissue below the valve annulus.

[0019] Furthermore, the distance d from the plane where the end of the inflow channel of the stent is located to the plane where the valve ring is located has a value range of 0<d≤15mm.

[0020] Another technical solution adopted by the present invention to solve the above technical problem is to provide a heart valve prosthesis, including a stent and leaflets, wherein the stent is the stent mentioned above, and the leaflets are fixed to the inner side of the stent.

[0021] Furthermore, the heart valve prosthesis also has an inner skirt, which is arranged on the inner side of the stent.

[0022] Furthermore, after the stent is released and expanded, the inflow channel has at least one contact position with the native tissue above the valve ring, and the stent is provided with an outer skirt at the contact position between the inflow channel and the native tissue.

[0023] Furthermore, after the stent is released and expanded, the inflow channel is closely fitted with the native tissue below the valve ring, and the stent is provided with an outer skirt at the fitting position of the inflow channel and the native tissue.

[0024] Compared with the prior art, the present invention has the following beneficial effects: the heart valve stent and its prosthesis provided by the present invention can prevent the risk of the stent moving from the inflow duct toward the outflow duct under the scouring of blood flow by setting a limiting structure at the position of the outflow duct or transition section of the stent. The inflow duct of the stent is set to a shape that matches the native tissue, and at the same time, an outer skirt is set on the outer circumference of the inflow duct at the place where it fits with the native tissue, which can effectively prevent paravalvular leakage. In addition, since the first protrusion is set and the inflow duct is set to adapt to the shape of the native tissue to achieve the fixation of the stent, the size of the inflow duct of the stent extending toward the valve annulus can be set shorter, which can effectively prevent atrioventricular conduction block. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of a heart valve stent according to an embodiment of the present invention;

[0026] Figure 2a Schematic diagram of a limiting structure on the stent outflow tract of a heart valve prosthesis according to an embodiment of the present invention;

[0027] Figures 2b to 2e Schematic diagram of the structure of the first protrusion on the limiting structure on the outflow channel of the stent of the heart valve prosthesis in an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the concave structure on the transition section of the stent of the heart valve prosthesis according to an embodiment of the present invention;

[0029] Figure 4a 、 Figure 4b Schematic diagram of the structure of the inflow duct of the heart valve prosthesis in an embodiment of the present invention.

[0030] In the picture:

[0031] 10 stents 20 valve rings 30 coronary sinus ostium

[0032] 101 Inflow channel 102 Transition section 103 Outflow channel

[0033] 104 contact position 1021 concave structure 1022 second protrusion

[0034] 1031 limiting structure 1032 first protrusion 40 sinus tube junction DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and examples.

[0036] Figure 1 Schematic diagram of the structure of a heart valve stent in an embodiment of the present invention.

[0037] The heart valve prosthesis provided by the present invention includes a stent 10, a valve leaflet and a skirt (not shown in the figure), see Figure 1 The stent 10 includes a stent body and a retaining structure 1031 connected to the stent body. The stent body is composed of interconnected grid structural units and is axially divided into an inflow channel 101, a transition section 102, and an outflow channel 103. Based on the direction of blood flow, the transition section 102 is located downstream of the inflow channel 101, and the outflow channel 103 is located downstream of the transition section 102. The inflow channel 101 corresponds to the portion of the prosthesis where blood flows into the valve during operation, and the outflow channel 103 corresponds to the portion where blood flows out of the prosthesis during operation. After the stent 10 is released and expanded, the inflow channel 101 matches the shape of the native tissue. The stent 10 is provided with a limiting structure 1031 along the circumferential direction on the outflow channel 103 or the transition section 102. The limiting structure 1031 has a first protrusion 1032 for limiting the movement of the stent 10 from the inflow channel 101 toward the outflow channel 103. Preferably, the limiting structure 1031 is provided on the outflow channel 103, and the vertical distance between the plane where the vertex of the first protrusion 1032 is located and the plane where the port of the outflow channel 103 is located is 0-30 mm; in another embodiment, the limiting structure 1031 is provided on the transition section 102. Preferably, the limiting structure 1031 is provided on the transition section 102 close to the outflow channel 103. Preferably, after the stent 10 is released and expanded, the port of the outflow tract 103 does not extend beyond the sinus-tubular junction 40. That is, the plane where the port of the outflow tract 103 lies is flush with or lower than the plane where the sinus-tubular junction 40 lies. The sinus-tubular junction 40 is the junction of the aortic sinus and the aorta. The limiting structures 1031 may be partially or completely distributed along the circumference, preferably completely distributed along the circumference.

[0038] In the heart valve prosthesis provided by the present invention, the stent 10 is made of metal material, preferably cut from nickel-titanium tubing. The leaflets and skirt are made of animal-derived materials, such as animal pericardium, or biocompatible polymer materials, such as polyurethane.

[0039] Figure 2a Schematic diagram of a limiting structure on the stent outflow tract of a heart valve prosthesis in an embodiment of the present invention.

[0040] See also Figure 1 and Figure 2a , the limiting structure 1031 has a first protrusion 1032, and the first protrusion 1032 is elastic and can be compressed in the radial and axial directions. The first protrusion 1032 can be made of the same material as the stent body, or other elastic materials or structures. The first protrusion 1032 can be manufactured integrally with the stent body, or it can be assembled and connected after being manufactured separately. The so-called integral manufacturing refers to cutting a metal pipe and then shaping it through heat treatment; or it can be woven from one or more metal wires. The so-called split manufacturing refers to manufacturing separately and then assembling and connecting them through welding or other methods. The first protrusion 1032 can be an arc-shaped protrusion, a trapezoidal protrusion, a wavy protrusion or a serrated protrusion, etc., such as Figures 2b to 2e As shown. The first protrusion 1032 has at least one protrusion. When the stent 10 is released and secured at a specific location in the heart, the protrusion is located in the area between the sinus-tubular junction 40 and the coronary sinus ostium 30, and may or may not contact the tissue located therebetween. The function of the first protrusion 1032 is to restrict the movement of the stent 10 along the direction of blood flow from the inflow tract to the outflow tract. When the stent 10 is subjected to external forces along the direction of blood flow, such as blood flow erosion, the stent 10 will tend to shift toward the sinus-tubular junction 40. Under the action of this external force, the at least one contact point between the first protrusion 1032 and the native tissue can restrict the stent 10 from further upward movement.

[0041] The stent 10 of the present invention has a grid unit structure, which is generally rhombus-shaped, but can also be other suitable shapes, such as pentagons, hexagons, etc., which can form closed-shaped units. In order to avoid the coronary sinus ostium 30 from being blocked, the transition section 102 can be designed to have a grid structure with a larger size, for example, the grid structure unit area is larger than the cross-sectional area of ​​the coronary sinus ostium 30, or the grid structure unit area of ​​the transition section 102 is larger than the grid structure unit area of ​​the inflow duct 101 or the outflow duct 103. The transition section 102 can also have a concave structure 1021 away from the first protrusion 1032, and in particular, the transition section 102 has a concave structure 1021 at the position of the coronary sinus ostium 30. The concave structure 1021 is concave in a direction away from the coronary sinus ostium 30 and has a certain distance from the coronary sinus ostium 30. The second protrusions 1022 are provided at both ends of the concave structure 1021, such as Figure 3 As shown, the concave structure 1021 can also prevent the coronary sinus ostium 30 from being blocked.

[0042] The shape of the inflow channel 101 of the stent 10 of the present invention is configured to be adapted to the shape of the native tissue to prevent paravalvular leakage. In order to more clearly describe the structural features of the present invention, the present invention uses "above" and "below" as directional words, with the inflow channel 101 located "below" and the outflow channel 103 located "above". Figure 4a As shown, there can be at least one contact position 104 between the annulus 20 and the native tissue above the annulus 20, and the annulus 20 can be closely fitted with the native tissue below the annulus 20. The contact position 104 between the annulus 20 and the native tissue above can further prevent paravalvular leakage. Alternatively, Figure 4b As shown, the inflow channel 101 is near the valve annulus 20 and fits closely with the native tissue.

[0043] In order to further prevent paravalvular leakage, a skirt is sewn on the inflow channel 101 of the stent 10, and the skirt can be single-layered or double-layered. A double-layer skirt means that both the inner and outer layers of the inflow channel 101 are sewn with skirts, the inner layer of the inflow channel 101 is sewn with an inner skirt, and the outer layer of the inflow channel 101 is sewn with an outer skirt. A single-layer skirt means that the inner layer of the inflow channel 101 is sewn with an inner skirt. The inner skirt is fixed to the inner side of the inflow channel 101 and fixedly connected to the leaflet. Preferably, the inner layer of the inflow channel 101 is sewn with an inner skirt, and the outer skirt is sewn at the contact position 104. The outer skirt is sewn at the fitting position of the inflow channel 101 and the native tissue, which can effectively prevent paravalvular leakage.

[0044] Because the stent 10 is secured by providing a first protrusion 1032 in the outflow tract 103 region and adapting the inflow tract 101 to the native tissue shape, the inflow tract 101 of the stent 10 can be relatively short, extending beyond the annulus 20. For example, the vertical distance d from the plane of the annulus 20 to the plane of the stent inflow tract 101's end can be within the range of 0 < d ≤ 15 mm. The d in the present invention is smaller than the d' of conventional stents, effectively preventing atrioventricular block; conventional stents have this portion longer to prevent paravalvular leakage, and stents that are too short tend to shift from the inflow tract toward the outflow tract.

[0045] In summary, the outflow duct 103 of the heart valve prosthesis and stent 10 involved in the present invention is provided with a limiting structure 1031 near the transition section 102, which can prevent the risk of the stent 10 moving from the inflow duct to the outflow duct under the scouring of blood flow. The inflow duct 101 of the stent 10 is set to a shape that matches the native tissue, and at the same time, an outer skirt is set on the outer circumference of the inflow duct 101 where it fits with the native tissue, which can effectively prevent paravalvular leakage. In addition, since the first protrusion 1032 is provided and the inflow duct 101 is adapted to the shape of the native tissue to achieve the fixation of the stent 10, the dimension of the inflow duct 101 of the stent 10 extending toward the valve annulus 20 can be set shorter, which can effectively prevent atrioventricular conduction block, embolism, etc. At the same time, the port of the outflow duct 103 does not need to extend out of the sinotubular junction 40, and the size of the outflow duct can also be set shorter to reduce the pressure on the aorta.

[0046] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A heart valve stent, comprising a stent body, wherein the stent body is composed of interconnected grid structure units, wherein the grid structure units are pentagonal or hexagonal units that can form a closed shape, and the stent body is divided into an inflow channel, a transition section, and an outflow channel that are connected in sequence in the axial direction, characterized in that: The stent also has a limiting structure connected to the stent body; after the stent is released and expanded, the inflow duct matches the shape of the native tissue, and the limiting structure is distributed along the circumferential direction on the outflow duct or the transition section close to the outflow duct, and the limiting structure has a first protrusion for limiting the movement of the stent from the inflow duct toward the outflow duct; the first protrusion is manufactured integrally with the stent body, cut from a metal pipe, and then shaped by heat treatment, or woven from one or more metal wires; the area of ​​the grid structure unit on the stent located in the transition section is larger than the area of ​​the grid structure unit of the inflow duct or the outflow duct; the distance between the plane where the vertex of the first protrusion is located and the plane where the outflow duct port is located is 0-30mm, and the distance d from the plane where the end of the inflow duct of the stent is located to the plane where the valve ring is located has a value range of 0<d≤15mm.

2. The heart valve stent according to claim 1, wherein The limiting structure and the bracket body are manufactured separately and then assembled.

3. The heart valve stent according to claim 1, wherein: The first protrusion is an arc-shaped protrusion, a trapezoidal protrusion, a wave-shaped protrusion or a sawtooth-shaped protrusion.

4. The heart valve stent according to claim 1, wherein: The transition section has a concave structure away from the first protrusion.

5. The heart valve stent according to claim 1, wherein: After the stent is released and expanded, the port of the outflow tract does not extend out of the sinus-tubular junction.

6. The heart valve stent according to claim 1, wherein: After the stent is released and expanded, the inflow channel has at least one contact position with native tissue above the valve annulus.

7. The heart valve stent according to claim 1 or 6, characterized in that: After the stent is released and expanded, the inflow channel is closely fitted with the native tissue below the valve ring.

8. A heart valve prosthesis comprising a stent and a valve leaflet, characterized in that: The stent is the stent according to any one of claims 1 to 7, and the leaflet is fixed to the inner side of the stent.

9. The heart valve prosthesis according to claim 8, wherein: The heart valve prosthesis further comprises an inner skirt, which is arranged on the inner side of the stent.

10. The heart valve prosthesis according to claim 9, wherein: After the stent is released and expanded, the inflow channel has at least one contact position with the native tissue above the valve ring, and the stent is provided with an outer skirt at the contact position between the inflow channel and the native tissue.

11. The heart valve prosthesis according to claim 8 or 10, characterized in that: After the stent is released and expanded, the inflow channel is closely fitted with the native tissue below the valve ring, and the stent is provided with an outer skirt at the fitting position of the inflow channel and the native tissue.

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