Valve stent and valve prosthesis

Abstract

The invention discloses a valve stent and a valve prosthesis, the valve stent comprises: an outer stent having a first connecting end; the inner stent is arranged in the outer stent, the inner stent is provided with a second connecting end, the second connecting end is located on the inner side of the first connecting end, and in the axial direction of the valve stent, a distance difference exists between the second connecting end and the first connecting end; the connecting frame is obliquely connected between the first connecting end and the second connecting end, so that stress between the inner stent and the outer stent is uneven, and the connecting frame is at least used for weakening radial force generated when the inner stent and the outer stent are extruded by the valve ring and decomposing axial force generated by blood pressure impact. Therefore, the impact of blood flow can be reduced, the inner stent can be prevented from axially jumping relative to the outer stent, the received radial force can be dispersed, and the pressure received by the inner stent in the radial direction is reduced, so that the relative stability of the shape and the size of the inner stent can be kept, and the occurrence of perivalvular leakage can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of heart valves, and in particular to a valve stent and a valve prosthesis. Background Art

[0002] Natural heart valves may malfunction due to various reasons, such as endocarditis, trauma, congenital dysplasia or malformation, aging, calcification, stenosis, etc. When the natural valve is abnormal, its normal function of preventing blood from flowing back will fail or partially fail due to incomplete closure or abnormal closure, resulting in reflux. Taking the mitral valve as an example, the mitral valve structure includes four parts: leaflets, annulus, chordae tendineae, and papillary muscles. The normal mitral valve function depends on the integrity of these four parts and the structure and function of the left ventricle. Any one or more of these parts with structural abnormalities or dysfunction will lead to mitral valve insufficiency, causing blood to flow back into the left atrium when the left ventricle contracts, forming mitral valve regurgitation. Interventional treatment methods mainly include mitral valve leaflet repair and mitral valve replacement. Mitral valve repair mainly uses auxiliary devices to repair the problem of incomplete closure of natural valve leaflets and reduce or eliminate regurgitation. Mitral valve replacement mainly eliminates mitral valve regurgitation by implanting valve prostheses. The biggest challenge for mitral valve replacement products is to fix the implanted prosthesis at the mitral valve annulus while reducing paravalvular leakage and impact on the aorta.

[0003] In current valve stent products, the entire valve prosthesis will be subjected to a force directed from the left ventricle to the left atrium under the impact of blood flow. Since the pressure in the left ventricle is very large, the impact force is also very large. The stent of the valve prosthesis is prone to axial jump, and it is also easy to cause the valve stent to impact the inner wall of the atrium, affecting the stability and performance of the valve prosthesis and increasing the probability of paravalvular leakage. The stent in the valve prosthesis can be a double-layer stent. For the double-layer stent, the outer stent and the inner stent are connected by a connecting section. During the heart contraction process, the outer stent will be squeezed by the valve ring and deformed. This squeezing force will be transmitted to the inner stent through the connecting section, causing the inner stent to be squeezed and resulting in a reduction in the original design size, thereby affecting the closing effect of the valve leaflet. In addition, the outer stent is squeezed. Since the valve ring is an irregular shape, the part connected to the valve ring is deformed, causing the valve stent to rotate, thereby increasing the probability of paravalvular leakage. At the same time, when heart failure is severe, the size of the valve annulus will expand significantly. The larger size of the valve annulus will increase the reverse impact of blood flow on the valve stent, causing the inner stent of the valve stent to axially jump relative to the outer stent under the impact of blood flow. The occurrence of this situation will lead to fatigue failure of the valve stent, and the impact on hemodynamics is also relatively obvious, affecting the treatment effect.

[0004] Therefore, it is an urgent problem to develop a device that can reduce blood flow impact, avoid axial vibration of the valve stent, reduce the force between the inner stent and the outer stent, avoid rotation of the valve stent, and reduce the probability of paravalvular leakage. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide a valve stent that can reduce the impact of blood flow, prevent the inner stent from axially jumping relative to the outer stent, and disperse the radial force received, so that the radial pressure received by the inner stent becomes smaller, thereby maintaining the relative stability of the shape and size of the inner stent, avoiding the rotation of the valve stent, avoiding the occurrence of paravalvular leakage, and increasing the anti-fatigue ability of the valve stent.

[0006] The present invention further provides a valve prosthesis.

[0007] According to the first aspect of the present invention, the valve stent comprises: an outer stent, the outer stent having a first connecting end; an inner stent, the inner stent is arranged in the outer stent, the inner stent has a second connecting end, the second connecting end is located on the inner side of the first connecting end, and in the axial direction of the valve stent, the second connecting end and the first connecting end have a distance difference; a connecting frame, the connecting frame is obliquely connected between the first connecting end and the second connecting end, so that the force between the inner stent and the outer stent is uneven, so that the connecting frame is at least used to weaken the radial force generated by the compression of the valve ring on the inner stent and the outer stent, and decompose the axial force generated by the blood pressure shock.

[0008] Therefore, the valve stent can disperse the radial force it is subjected to and reduce the radial pressure on the inner stent, thereby maintaining the relative stability of the shape and size of the inner stent, preventing the inner stent from axially jumping relative to the outer stent, and avoiding the occurrence of paravalvular leakage.

[0009] According to some embodiments of the present invention, the inner support has a first end and a second end that are axially opposite, the second connecting end is located at the second end of the inner support, and in the axial direction of the valve support, the second connecting end is located between the first end and the first connecting end; preferably, the distance difference between the second connecting end and the first connecting end makes the inclination angle of the connecting frame to the horizontal plane be 18-80 degrees, so as to weaken the upward axial force generated by the inner support under the blood pressure, and reduce the bending force borne by the connecting frame by 5-82.6%. Preferably, the distance difference between the second connecting end and the first connecting end makes the inclination angle of the connecting frame to the horizontal plane be 15-65 degrees.

[0010] According to some embodiments of the present invention, the outer stent includes: an outer stent body; an outer annulus segment, the outer annulus segment is arranged to extend along the axial direction of the outer stent body, and a plurality of the outer annulus segments are arranged along the circumferential direction of the outer stent body to match an annulus. The outer annulus segment has a third end and a fourth end, the outer stent body is connected to the third end, and the first connection end is located at the fourth end; wherein, in the axial direction of the valve stent, the third end is located between the first connection end and the second connection end.

[0011] According to some embodiments of the present invention, the inner stent has a first end and a second end that are axially opposite, the second connection end is located at the second end of the inner stent, and in the axial direction of the valve stent, the first connection end is located between the first end and the second connection end.

[0012] According to some embodiments of the present invention, the outer stent includes: an outer stent body; an outer annulus segment, the outer annulus segment is arranged to extend along the axial direction of the outer stent body, and a plurality of the outer annulus segments are arranged along the circumferential direction of the outer stent body to match an annulus. The outer annulus segment has a third end and a fourth end, the outer stent body is connected to the third end, and the first connection end is located at the fourth end; wherein, in the axial direction of the valve stent, the third end is located between the first end and the first connection end.

[0013] According to some embodiments of the present invention, the outer stent body is configured as a spherical shape with an opening, the structure of the outer stent body abuts against the atrial wall, the outer annulus segment is located at the opening, and the outer annulus segment is located at the annulus position.

[0014] According to some embodiments of the present invention, the distance between the third end and the fourth end of the outer annulus segment is L1, L1 is not less than the axial length of the annulus, and L1 satisfies the relationship: 1 mm ≤ L1 ≤ 15 mm.

[0015] According to some embodiments of the present invention, the connecting frame includes at least one connecting rod, and the at least one connecting rod is connected between the first connecting end and the second connecting end. The width of the connecting rod is W, and it satisfies the relationship: 0.1 mm ≤ W ≤ 2.5 mm; preferably, the width of the connecting rod is greater than the width of the support rod of the outer support, so that the toughness of the outer support is less than that of the connecting rod; preferably, the width of the connecting rod is greater than the width of the support rod of the inner support, so that the rigidity of the inner support is greater than that of the connecting rod; the distance difference is L2, and L2 satisfies the relationship: L2 ≤ 25 mm; a plane perpendicular to the inner support is set as the reference plane, and the included angle α between the connecting frame and the reference plane satisfies the relationship: 2° ≤ α ≤ 80°; the connecting frame includes: a connecting section and a transition section, and the transition section is respectively connected to both sides of the connecting section. One side of the transition section is connected to the first connecting end and the other side of the transition section is connected to the second connecting end; wherein, the connecting section is at least one of an arc structure, an S-shaped structure, a wavy structure, a V-shaped structure, and a grid-like structure; and / or the transition section is at least one of an arc structure, a straight rod structure, a single rod structure, a multi-rod structure, and a grid-like structure.

[0016] According to some embodiments of the present invention, the outer support, the inner support, and the connecting frame are integrally formed.

[0017] The valve prosthesis according to the second aspect embodiment of the present invention includes: the above-mentioned valve stent, valve leaf, and suture membrane; the valve leaf is connected to the inner support of the valve stent; the suture membrane is arranged on the inner support and the outer support of the valve stent.

[0018] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0019] The above-mentioned and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0020] Figure 1 is a schematic structural diagram of a valve stent according to an embodiment of the present invention;

[0021] Figure 2 is a schematic structural diagram of a valve stent according to another embodiment of the present invention;

[0022] Figure 3 is a schematic structural diagram of the distance between the third end and the fourth end of the outer valve ring segment according to an embodiment of the present invention

[0023] Figure 4Schematic diagram of the structure where the second connection end and the first connection end have a distance difference according to an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the width of the connecting rod in the connecting frame according to an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of the angle between the connecting frame and the reference plane according to an embodiment of the present invention;

[0026] Figure 7 Schematic diagram of the valve stent in the atrium according to an embodiment of the present invention;

[0027] Figure 8 Schematic diagram of the force decomposition of the connecting frame according to an embodiment of the present invention.

[0028] Reference numerals:

[0029] 100, valve stent;

[0030] 10, outer stent; 11, first connection end; 12, outer stent main body; 13, outer valve ring segment; 131, third end; 132, fourth end;

[0031] 20, inner stent; 21, second connection end; 23, first end; 24, second end;

[0032] 30, connecting frame; 31, connecting segment; 32, transition segment. Detailed implementation manners

[0033] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the drawings are exemplary.

[0034] Below, refer to Figures 1 - 8 Describe the valve stent 100 according to an embodiment of the present invention.

[0035] As Figure 1 And Figure 7As shown, the valve stent 100 according to the embodiment of the first aspect of the present invention includes: an outer stent 10, an inner stent 20, and a connecting frame 30. The outer stent 10 has a first connection end 11. The inner stent 20 is disposed inside the outer stent 10. The inner stent 20 has a second connection end 21, and the second connection end 21 is located inside the first connection end 11. In the axial direction of the valve stent 100, there is a distance difference between the second connection end 21 and the first connection end 11, that is, along the axial direction of the valve stent 100, the bottom of the outflow end of the inner stent 20 (in this application, the "lower end" represents the "outflow end", and the outflow end represents the end where blood flows out. The "upper end" represents the "inflow end", and the inflow end represents the end where blood flows in.) is higher than or lower than the bottom of the outer stent 10. The connecting frame 30 is obliquely connected between the first connection end 11 and the second connection end 21, so that the force between the inner stent 20 and the outer stent 10 is uneven, and the connecting frame 30 is at least used to weaken the radial force generated by the inner stent 20 and the outer stent 10 being squeezed by the valve annulus, and decompose the axial force generated by the blood pressure impact.

[0036] Preferably, when the distance difference between the second connection end 21 and the first connection end 11 makes the inclination angle of the connecting frame 30 with the horizontal plane be 18 - 80 degrees, it can weaken the upward axial force generated by the inner stent 20 under the blood pressure, and can reduce the bending force borne by the connecting frame 30 by up to 5 - 82.6% at most. At the same time, an additional radial force between the inner stent 20 and the outer stent 10 is generated to keep the outer stent 10 in close contact with the valve annulus. Specifically, when the blood flow generates an impact force upward towards the inner stent 20, and the impact pressure reaches more than 120 mmHg, the inner frame of the existing valve stent will jump under the action of the impact force. The applicant verified that when the blood flow impact is within the range of 160 mmHg, the jumping can be effectively avoided. Further, in order to weaken the bending deformation of the connecting frame 30 between the inner stent 20 and the outer stent 10 to reduce the jumping amplitude of the inner stent 20, the applicant verified through various means, such as Figure 6 and Figure 8As shown, in the axial direction of the inner stent 20, when the included angle between the connecting frame 30 of the inner stent 20 and the outer stent 10 and the horizontal plane is 18 - 80 degrees, the connecting frame 30 can effectively reduce the bending force generated due to the impact force on the inner stent 20. For example, when the inner stent 20 is subjected to an upward axial force F, when there is no included angle between the connecting frame 30 and the horizontal plane, the bending force on the connecting frame 30 is the axial force F. In this way, the bending force on the connecting frame 30 is relatively large. When there is an included angle between the connecting frame 30 and the horizontal plane, the bending force on the connecting frame 30 is the component force F1 of the axial force F. Thus, the bending force generated due to the impact force on the inner stent 20 can be effectively reduced, and by decomposing the axial force F of the inner stent 20, the axial force on the inner stent 20 can be further reduced, thereby avoiding the jumping of the inner stent 20. Further, through theoretical research, simulation of actual blood flow impact tests, clinical research, etc., the applicant found that when the included angle is 15 - 65 degrees, the bending amplitude of the connecting frame 30 can be effectively reduced, thereby preventing the jumping of the valve stent 100.

[0037] The valve stent 100 of the present application solves the technical problems in the field of valve replacement, especially in mitral valve replacement, such as unstable anchoring, paravalvular leakage, deformation of the inner stent caused by radial compression of the valve annulus, and axial jumping of the inner stent caused by blood flow impact, through the mutual cooperation among the inner stent 20, the outer stent 10, and the connecting frame 30. Specifically, in the axial direction of the valve stent 100, since the valve stent 100 includes the outer stent 10 and the inner stent 20, the axial direction of the valve stent 100, that is, the axial direction of the outer stent 10 or the axial direction of the inner stent 20, is coaxial with the axial direction of the outer stent 10 and the axial direction of the inner stent 20. There is a distance difference between the second connection end 21 of the inner stent 20 and the first connection end 11 of the outer stent 10, and an inclined connecting frame 30 is provided between the first connection end 11 and the second connection end 21. The inclined connecting frame 30 is relative to the axial and radial directions of the inner stent 20. This connecting frame 30 is not arranged along the axial direction of the inner stent 20 nor along the radial direction of the inner stent 20, such that the second connection end 21 and the first connection end 11 are not in the same axial position, that is, the connecting frame 30 is a non-horizontal structure. As Figure 8 shown, the connecting frame 30 is inclined, having the following beneficial effects:

[0038] First, the radial force applied to the outer stent 10 when the valve annulus contracts can be dispersed, and the pressure on the inner stent 20 in the radial direction can also be reduced, thereby maintaining the relative stability of the shape and size of the inner stent 20 to maintain a better leaflet closing effect. Moreover, the radial supporting force exerted by the outer stent 10 at the valve annulus is reduced, which can avoid squeezing the left ventricular outflow tract and the aortic root, and reduce the occurrence of aortic stenosis and left ventricular outflow tract obstruction. In addition, the squeezing of the valve annulus also restricts the upward movement of the connecting frame 30 and the inner stent 20, thereby alleviating the axial jumping of the inner stent 20 caused by blood flow impact.

[0039] Second, when blood flow generates an impact force upward towards the connecting frame 30, the axially inclined connecting frame 30 decomposes the axial force generated by the blood pressure impact, which can weaken the axial impact force of the blood pressure on the valve stent 100, improve the stability of the valve stent 100 at the annulus position, and prevent the inner stent 20 from axially jumping relative to the outer stent 10.

[0040] Third, it should be understood that the annulus tissue is not an absolute circular structure, but a three-dimensional saddle-shaped structure. The outer stent 10 is generally designed with an oversize dimension. Therefore, after the valve stent 100 is implanted into the annulus part, the annulus will exert an unequal force on the outer stent 10, which requires that the stent of the annulus section of the valve stent 100 has good conformability and shape adaptability to the annulus part. Moreover, the inner stent 20 has the function of bearing the valve leaflets. The more stable the size structure of the inner stent 20, the better the opening and closing function of the valve leaflets. The inclined setting of the connecting frame 30 can increase the connection toughness between the inner stent 20 and the outer stent 10 of the valve stent 100, thereby increasing the conformability and shape adaptability of the annulus section, enabling the valve stent 100 to be in close contact with the annulus tissue, contributing to endothelialization, and avoiding the occurrence of paravalvular leakage. It can also prevent the radial force of the outer stent 10 from directly affecting the force on the inner stent 20, so that the direct influence of the radial force on the inner stent 20 is small. When the outer stent 10 is squeezed, the inner stent 20 can withstand the squeeze without obvious dimensional deformation.

[0041] Fourth, since the valve prosthesis needs to be delivered through a sheath during implantation, the valve stent needs to be radially compressed when the valve prosthesis is installed in the sheath. During the radial compression process, the stent of the valve prosthesis will deform, especially at the bottom of the valve stent (the part at the outflow end), and its bottom will deform due to extrusion (changes different from the original structure). To resist this deformation, the reaction force at the bottom will make it difficult for the valve stent to enter the sheath. However, for the valve stent 100 provided in this embodiment, due to the inclined setting of the connecting frame 30, during radial compression, the bottom of the connecting frame 30 will conform to this deformation, making the process of pulling the valve stent 100 into the delivery sheath from the top of the connecting head easier. At the same time, the valve stent 100 of this embodiment can be implanted through two methods: transapical and transfemoral approaches, realizing minimally invasive treatment.

[0042] In this embodiment, by designing the connecting frame 30 to be inclined, on the basis of ingenious structural improvements, the valve stent 100 has the above-mentioned beneficial effects. Such prominently, surprisingly, and unexpectedly beneficial effects have made remarkable progress and produced outstanding substantial improvements. Those skilled in the art all know that valve stents are used in the heart, and any minor improvement will bring about a qualitative change in minimally invasive treatment. At the same time, for these designs of the applicant, even those who are familiar with the technology in this field would not think of affecting the impact of actual cardiac blood flow on the valve stent through such structural improvements, nor would they think of improving the force change between the inner stent 20 and the outer stent 10 after the annulus squeezes the valve stent 100 to ensure the stability of the inner stent 20. Even less would they think that such a design would enable a good fit between the valve stent 100 and the annulus, and also make it easier to insert the sheath and prevent the valve stent from deforming.

[0043] Preferably, the overall contour of the inner stent 20 is a cylindrical structure to ensure the stability of blood flow when blood flows through the inner stent 20 and provide connection points for the setting of valve leaflets. The stent structure of the inner stent 20 can be at least one of a mesh structure, an arc structure, a quadrilateral structure, a hexagonal structure, a straight rod structure, and a braided structure, so as to have different stiffness characteristics.

[0044] Preferably, the outer stent 10 includes an overall contour that is approximately spherical and a bottom that is cylindrical. The top stent rods of the outer stent 10 are in a free state and are bundled through a connection head. The connection head includes a connection structure that matches the delivery system for assembling the stent with the system to achieve the implantation and release of the stent. The suture membrane is arranged on the inner side of the inner stent 20 and the outer side of the outer stent 10 to perform the functions of sealing and promoting endothelialization. The structure of the outer stent 10 can be at least one of a curved rod structure, a mesh structure, an arc structure, a quadrilateral structure, a hexagonal structure, and a braided structure, so as to provide different supporting forces.

[0045] According to some embodiments of the present invention, as Figure 1 shown, the inner stent 20 has a first end 23 and a second end 24 that are axially opposite. The second connection end 21 is located at the second end 24 of the inner stent 20. Axially on the inner stent 20, the second connection end 21 is located between the first end 23 and the first connection end 11. That is, the second connection end 21 is higher than the first connection end 11. Thus, when the annulus squeezes the annulus section of the valve stent 100, the first connection end 11 of the outer stent 10 transmits the squeezing force to the second connection end 21 through the connecting frame 30, so that a part of the squeezing force can be dispersed. The second connection end 21 transmits the remaining squeezing force to the inner stent 20, thereby reducing the influence of the annulus squeezing force received by the outer stent 10 on the inner stent 20.

[0046] According to a specific embodiment of the present invention, as Figure 1 shown, the outer stent 10 includes: an outer stent main body 12 and an outer annulus segment 13. The outer stent main body 12 contacts the atrial endocardium and mainly functions to support and fix. The outer annulus segment 13 extends axially along the outer stent main body 12, and a plurality of outer annulus segments 13 are arranged circumferentially along the outer stent main body 12 to match an annulus. For example, the outer annulus segment 13 is a cylindrical structure that matches the shape at the annulus. When the connecting frame 30 bears the extrusion of the outer annulus segment 13, under the action of the moment generated between the inner and outer frames, it will bend and the inclination angle will change, thereby absorbing the radial displacement generated by the outer annulus segment 13, so as to prevent the inner stent 20 from bending and deforming during the process of receiving the axial force and increasing the beating amplitude of the inner stent 20. The outer annulus segment 13 can be a single-rod structure or a V-shaped structure formed by connecting two rods. After the valve stent is implanted into the human body, the outer stent main body 12 fits with the inner wall of the atrium, and through the supporting force, it plays a fixing role on the valve stent 100, preventing the valve from deflecting and axial movement caused by the blood flow. The outer annulus segment 13 fits with the annulus, provides radial pressure, and through the combined action with the suture membrane, reduces the blood leakage at the annulus. At the same time, the outer annulus segment 13 penetrates into the annulus, which can prevent the valve stent 100 from rotating in the atrium.

[0047] The outer annulus segment 13 has a third end 131 and a fourth end 132. The outer stent main body 12 is connected to the third end 131, and the first connection end 11 is located at the fourth end 132. Among them, along the axis of the valve stent, the third end 131 is located between the first connection end 11 and the second connection end 21, that is, the second connection end 21 is higher than the third end 131. Thus, when the outer stent 10 is squeezed and deformed, the reduction in the size of the outer stent 10 will be absorbed by the bending deformation (change in the inclination angle) of the connecting segment 31, and it will not cause a reduction in the size of the inner stent 20. Moreover, the upward inclination design of the connecting segment 31 can prevent the valve stent 100 from invading the ventricle too much and can avoid affecting the ventricular outflow tract. The upward and downward inclination methods of the connecting segment 31 can facilitate the overall pulling of the valve stent 100 into the sheath. Also, the cylindrical structure of the inner stent 20 and the leaf prosthesis connected thereto are above the annulus, so that the outer annulus segment 13 is in close contact and cooperation with the annulus, which can avoid the occurrence of perivalvular leakage and also play a fixing role. By setting the second connection end 21 to be higher than the third end 131, the inner stent 20 is entirely located inside the outer stent main body 12, which is beneficial to the arrangement of the inner stent 20 inside the outer stent 10. Moreover, this can extend the length of the connecting frame 30, increase the force transmission distance between the inner stent 20 and the outer stent 10, extend the force transmission time, thereby reducing the influence of the force on the inner stent 20, and enabling the inner stent 20 to withstand extrusion without obvious dimensional deformation.

[0048] According to some embodiments of the present invention, as Figure 2 andFigure 3 As shown, the inner support 20 has an axially opposite first end 23 and a second end 24, the second connecting end 21 is located at the second end 24 of the inner support 20, and in the axial direction of the inner support 20, the first connecting end 11 is located between the first end 23 and the second connecting end 21, that is, the second connecting end 21 of the inner support 20 is lower than the first connecting end 11 of the outer support 10. In this way, the connecting frame 30 extends downwardly from the first connecting end 11 obliquely until it is connected to the second connecting end 21, and the radial force received by the first connecting end 11 is dispersed through the downwardly inclined connecting frame 30. In this way, the valve support has the following features: 1) The connecting frame 30 can further disperse the radial force received, thereby reducing the radial pressure received by the inner support 20, and can also keep the shape and size of the inner support 20 relatively stable, so as to maintain a better leaflet closure effect. 2) The structure of the downwardly inclined valve stent 100, when the blood pressure exerts an upward impact force on the valve stent 100, the structure of the connecting frame 30 can weaken the axial force of the blood pressure impact on the one hand, and on the other hand, since the suture membrane and valve leaflets of the connecting frame 30 will be impacted by the blood flow when the ventricle contracts and generate a force directed to the atrium, the inner stent 20 and the connecting frame 30 will be displaced upward, and the degree of displacement depends on the pressure of the ventricle, the size of the projection of the connecting frame 30 toward the outflow end, and the bending stiffness of the connecting section 31. When the upward displacement occurs, since the size of the connecting frame 30 is larger than the radial size of its projection at the valve ring, the upward displacement of the inner stent 20 will cause the connecting section 31 to generate an outward squeezing force on the valve ring, and this squeezing force will strengthen the radial support force at the outer stent 10 and the valve ring, thereby generating resistance to the axial movement of the entire valve stent 100. It is understandable that when subjected to an upward force, the outer valve ring segment connected to the third end of the connecting frame 30 can also provide a downward reaction force to the inner support 20 and the second connecting end 21, thereby resisting the impact force of blood pressure, maintaining the inner support 20 relatively stable, and preventing the inner support 20 from axially jumping. Since the extrusion of the valve ring can also limit the upward movement of the connecting frame 30 and the inner support 20, the axial jumping of the inner support 20 caused by the impact of blood flow can be alleviated. 3) Since the original valve ring part has the original valve leaflet when the valve stent 100 is implanted, when the valve stent 100 is implanted in the valve ring part, the outer valve ring segment 13 of the valve stent 100 and the connecting frame 30 can open and fix the original valve leaflet, and prevent the original valve leaflet from moving toward the central axis of the valve stent 100 under the action of blood flow and blood pressure. 4) The bending resistance of the inner support 20 can be enhanced. In short, the second connection end 21 of the inner stent 20 is lower than the first connection end 11 of the outer stent 10, which can effectively prevent the occurrence of paravalvular leakage. When the ventricle contracts, the upward movement of the inner stent 20 will increase the compression between the valve stent 100 and the valve ring, thereby better solving the problem of paravalvular leakage. It can also prevent the inner stent 20 from bouncing up and down, maintain the close contact between the valve stent 100 and the valve ring tissue, and help endothelialization.

[0049] According to another embodiment of the present invention, as Figure 2 and Figure 3 shown, the outer stent 10 includes: an outer stent body 12 and an outer annulus segment 13. The outer annulus segment 13 is arranged to extend along the axial direction of the outer stent body 12, and a plurality of outer annulus segments 13 are arranged circumferentially along the outer stent body 12 to match an annulus. The characteristics of the outer stent body 12 and the outer annulus segment 13 can be referred to the above description and will not be elaborated here. The outer annulus segment 13 has a third end 131 and a fourth end 132. The outer stent body 12 is connected to the third end 131, and the first connection end 11 is located at the fourth end 132. Among them, in the axial direction of the inner stent 20, the third end 131 is located between the first end 23 and the first connection end 11, that is, the first end 23 is higher than the third end 131. In this way, it can be ensured that the opening position of the valve leaf of the valve prosthesis is basically the same as the opening position of the valve leaf at the original annulus, so as not to have too much influence on hemodynamics. Among them, the outer annulus segment 13 fits with the annulus, can provide radial pressure, and through the combined action with the suture membrane, reduce the blood leakage at the annulus. At the same time, the outer annulus segment 13 extends deep into the annulus, so as to prevent the outer stent 10 from rotating in the atrium.

[0050] According to some embodiments of the present invention, as Figure 1 shown, the outer stent body 12 is configured as a spherical shape with an opening. The structure of the outer stent body 12 abuts against the atrial wall, and the outer annulus segment 13 is located at the opening. The outer annulus segment 13 is located at the annulus position. Preferably, the width of the stent rod of the outer annulus segment 13 is greater than the width of the stent rod of other parts, so that the bending resistance of the outer annulus segment 13 can be stronger than that of other parts.

[0051] Among them, setting the outer stent body 12 as a spherical shape can make the outer stent body 12 better fit with the inner wall of the atrium and can also provide a supporting force, so as to prevent the outer stent 10 from deflecting and axially moving under the action of blood flow. In addition, the outer stent body 12 is provided with an opening, and the opening is located below the outer stent body 12. The opening can be in a trumpet shape. The structure of the outer stent body 12 abuts against the atrial wall, and the outer annulus segment 13 is located at the opening. When the atrium expands, the blood in the ventricle can flow through the opening into the atrium, so as to facilitate the blood circulation between the atrium and the ventricle. The outer annulus segment is connected to both sides of the opening, and the outer annulus segments on both sides of the opening are symmetrically arranged about the axis of the valve stent 100. When the outer annulus segment 13 of the outer stent 10 is squeezed by the annulus, during the process of the opening being subjected to radial pressure, it can absorb a part of the deformation, so as to reduce the deformation of the outer stent body 12. In the fixing method of the valve prosthesis in this embodiment, a double-layer stent design is adopted. The inner stent 20 can carry artificial valve leafs to replace the function of the normal mitral valve leaf. The outer stent 10 contacts with the atrium. The outer stent 10 is fixed by the atrium, playing a role of fixing and supporting to prevent the stent from being flushed into the atrium.

[0052] In order to better maintain the dimensional and morphological stability of the inner stent 20 during the process of being squeezed by the annulus, the region where the bottom structure of the outflow tract (the channel for blood to flow out) of the cylindrical structure of the inner stent 20 is connected to the connecting frame 30 can be an open structure or a tapered structure. That is, the inflow tract is cylindrical, and the diameter of the outflow tract is larger than that of the cylindrical inflow tract, forming a flared structure. The open structure or the tapered structure can absorb a part of the deformation during the process of being subjected to radial pressure, reducing the deformation of the upper part (the position where the valve leaf is fixed) of the inner stent 20.

[0053] According to some embodiments of the present invention, as Figure 3 shown, the distance between the third end 131 and the fourth end 132 of the outer annulus segment 13 is L1, and L1 is not less than the axial length of the annulus. L1 satisfies the relationship: 1 mm ≤ L1 ≤ 15 mm. In this way, the connection region between the outer stent 10 and the outer annulus segment 13 can have a certain bending resistance, thereby preventing the inner stent 20 from bending and deforming during the process of being subjected to axial force, and preventing the outer stent main body 12 from penetrating too deep into the ventricle. The outer annulus segment 13 may touch or impact the endocardium during ventricular contraction, causing other serious complications.

[0054] According to some embodiments of the present invention, as Figure 5As shown, the connecting frame 30 includes at least one connecting rod, at least one connecting rod is connected between the first connecting end 11 and the second connecting end 21, and the width of the connecting rod is W, satisfying the relationship: 0.1mm≤W≤2.5mm, preferably, the width of the connecting rod is greater than the width of the stent rod of the outer stent 10, so that the toughness of the outer stent 10 is less than the toughness of the connecting rod. Preferably, the width of the connecting rod is greater than the width of the stent rod of the inner stent 20, so that the rigidity of the inner stent 20 is greater than the rigidity of the connecting rod. Too large a width of the connecting rod will increase the sheathing size and sheathing force of the overall valve stent 100, and too small a width of the connecting rod will reduce the supporting force of the connecting rod, causing the connecting rod to break. Among them, the connecting frame 30 can be one of a single rod, a multi-rod or a grid-like structure, and can also be set to a combination of two or more of a single rod, a multi-rod or a grid-like structure. For example, the connecting frame 30 can be set to a single connecting rod, and the single connecting rod can be set upwardly inclined between the first connecting end 11 and the second connecting end 21, or can be set downwardly inclined between the first connecting end 11 and the second connecting end 21, which can be selected according to actual conditions. In this way, the connecting frame 30 is tilted, which can not only provide outward support force, but also prevent the inner stent 20 from axially jumping, and can also disperse radial force, so that the radial pressure on the inner stent 20 can be reduced, and the shape and size of the inner stent 20 can be kept relatively stable, and the inner stent 20 can be prevented from axially jumping relative to the outer stent 10. Further, the size range of the connecting rod width is 0.1mm to 2.5mm. If the width of the connecting rod is too large, the size and sheathing force of the valve stent 100 will increase. If the width of the connecting rod is too small, the supporting force of the connecting rod will be reduced, resulting in the breaking of the connecting rod. In this way, setting the size range of the connecting rod width to 0.1mm to 2.5mm can ensure the strength and supporting force of the connecting rod, and can also reduce the overall size of the valve stent 100 and the weight of the valve stent 100.

[0055] According to some embodiments of the present invention, Figure 4As shown, the distance difference is L2, and L2 satisfies the relation: L2 ≤ 25 mm. Among them, the distance difference between the first connection end 11 and the second connection end 21 can form an accommodation space between the first connection end 11 and the second connection end 21, which is convenient for the setting of the connection frame 30. The connection frame 30 located in the accommodation space can not only disperse the radial force, but also provide an outward supporting force and has a certain bending stiffness, so as to ensure the stability of the valve stent 100. For the downward-sloping inner stent 20, if the distance difference is too large, it will cause the inner stent 20 to extend too long into the ventricle, there will be a risk of contact during ventricular contraction, and at the same time, it will block the left ventricular outflow tract and affect blood flow supply; for the upward-sloping inner stent 20, if the distance difference is too large, the inner stent 20 will extend too much into the atrium, which will also cause the blood in the atrium to not flow smoothly into the ventricle, resulting in poor blood supply and the risk of thrombosis. Such a distance difference can reduce the impact of the inner stent 20 on the patient's heart after implantation and avoid risks.

[0056] According to some embodiments of the present invention, as Figure 6 shown, a plane perpendicular to the inner stent 20 is set as the reference plane, and the angle between the connection frame 30 and the reference plane is α, and α satisfies the relation: 2° ≤ α ≤ 80°. Among them, the angle between the connection frame 30 and the plane perpendicular to the inner stent 20 is an acute angle. In this way, when the connection frame 30 is subjected to a squeezing force, the squeezing force can be prevented from being directly transmitted radially. The connection frame 30 can disperse the squeezing force, so that the pressure on the inner stent 20 in the radial direction can be reduced, and the relative stability of the shape and size of the inner stent 20 can be maintained. Too small an inclination angle will not play the role of decomposing the force in different directions, and too large an inclination angle will affect the position height of the inner stent 20 and the performance of the valve stent 100.

[0057] According to the specific embodiments of the present invention, as Figure 2As shown in the figure, the connecting frame 30 includes a connecting section 31 and a transition section 32. The transition section 32 is respectively connected to both sides of the connecting section 31. One side of the transition section 32 is connected to the first connection end 11, and the other side of the transition section 32 is connected to the second connection end 21. Specifically, the connecting frame 30 is mainly composed of the connecting section 31 and the transition section 32. The connecting section 31 can be a straight section, and the transition section 32 can be set as an arc section. The arc transition section 32 on one side is connected to the first connection end 11, which can absorb the extrusion force and play a buffering role, reducing the force at the connection between the transition section 32 and the first connection end 11, thereby avoiding stress concentration. Similarly, the arc transition section 32 on the other side is connected to the second connection end 21, which can also play a buffering role, thus avoiding stress concentration at the connection between the arc transition section 32 on the other side and the second connection end 21. According to some embodiments of the present invention, the connecting section 31 is at least one of an arc-shaped structure, an S-shaped structure, a wavy structure, a V-shaped structure, and a grid-like structure, or a combination of several of these structures. The transition section 32 is at least one of an arc structure, a straight rod structure, a single rod structure, a multi-rod structure, and a grid-like structure. That is, the transition section 32 can be set as one of the arc structure, the straight rod structure, the single rod structure, the multi-rod structure, and the grid-like structure, or a combination of two or more of the arc structure, the straight rod structure, the single rod structure, the multi-rod structure, and the grid-like structure. Similarly, the connecting section 31 can be set as one of the arc-shaped structure, the S-shaped structure, the wavy structure, the V-shaped structure, and the grid-like structure, or a combination of two or more of the arc-shaped structure, the S-shaped structure, the wavy structure, the V-shaped structure, and the grid-like structure. In this way, the connecting frame 30 can have different mechanical properties, so that the connecting frame 30 can provide different supporting forces and bending resistances, and thus the valve stent 100 can adapt to different occasions.

[0058] According to some embodiments of the present invention, the outer stent 10 has a plurality of first connection ends 11, the inner stent 20 has a plurality of second connection ends 21, and the plurality of first connection ends 11, the plurality of second connection ends 21, and the plurality of connecting frames 30 are connected in one-to-one correspondence. For example, the plurality of first connection ends 11, the plurality of second connection ends 21, and the plurality of connecting frames 30 are arranged at intervals along the circumferential direction of the outer stent 10. In this way, the overall stiffness of the valve stent 100 can be improved, and the radial force of the valve stent 100 in the circumferential direction can also be reduced, thereby ensuring the relative stability of the shape and size of the inner stent 20.

[0059] According to some embodiments of the present invention, the outer stent 10, the inner stent 20, and the connecting frame 30 are integrally formed. The forming method of the outer stent 10, the inner stent 20, and the connecting frame 30 can be to cut out a pattern on a shape memory metal tube and then obtain the target shape through heat setting or other methods, or to braid with shape memory metal wires and then perform shaping to obtain the target shape.

[0060] The valve prosthesis according to the embodiment of the second aspect of the present invention includes: the valve stent 100 of the above embodiment, valve leaflets, and a suture membrane. The valve leaflets are connected to the inner stent 20 of the valve stent 100, and the suture membrane is disposed between the inner stent 20 and the outer stent 10 of the valve stent 100.

[0061] Wherein, the valve stent 100 is disposed at the annulus position, and the dimensional range where the inner stent 20 is higher or lower than the annulus can be between 1 - 100 mm. If the inner stent 20 is too high, the blood in the atrium cannot flow well into the ventricle, leading to the formation of thrombus. When the inner stent 20 is lower than the annulus, the inner stent 20 extends deep into the ventricle, occupying more ventricular space, resulting in a reduction in the ejection volume, and being affected by ventricular compression.

[0062] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0063] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A valve stent, characterized in that, Comprising: An outer stent, the outer stent having a first connection end; An inner stent, the inner stent being disposed within the outer stent, the inner stent having a second connection end, the second connection end being located inside the first connection end, and in the axial direction of the valve stent, there is a distance difference between the second connection end and the first connection end; A connecting frame, the connecting frame being obliquely connected between the first connection end and the second connection end, so that the force received between the inner stent and the outer stent is uneven, and the connecting frame is at least used to weaken the radial force generated by the inner stent and the outer stent being squeezed by the valve annulus and decompose the axial force generated by the blood pressure impact.

2. The valve stent according to claim 1, wherein, The inner stent has an axially opposite first end and second end, the second connection end is located at the second end of the inner stent, and in the axial direction of the valve stent, the second connection end is located between the first end and the first connection end; Preferably, the distance difference between the second connection end and the first connection end makes the inclination angle of the connecting frame with the horizontal plane be 18 degrees - 80 degrees, so as to weaken the upward axial force generated by the inner stent under blood pressure and reduce the bending force received by the connecting frame by 5% - 82.6%; Preferably, the distance difference between the second connection end and the first connection end makes the inclination angle of the connecting frame with the horizontal plane be 15 degrees - 65 degrees.

3. The valve stent according to claim 2, wherein The outer stent includes: An outer stent body; An outer valve annulus segment, the outer valve annulus segment extending along the axial direction of the outer stent body, and a plurality of the outer valve annulus segments are arranged along the circumferential direction of the outer stent body to match a valve annulus. The outer valve annulus segment has a third end and a fourth end, the outer stent body is connected to the third end, and the first connection end is located at the fourth end; Wherein, along the axial direction of the valve stent, the third end is located between the first connection end and the second connection end.

4. The valve stent according to claim 1, characterized in that, The inner stent has an axially opposite first end and second end, the second connection end is located at the second end of the inner stent, and in the axial direction of the valve stent, the first connection end is located between the first end and the second connection end.

5. The valve stent according to claim 4, characterized in that, The outer stent includes: An outer stent body; An outer valve annulus segment, the outer valve annulus segment extending along the axial direction of the outer stent body, and a plurality of the outer valve annulus segments are arranged along the circumferential direction of the outer stent body to match a valve annulus. The outer valve annulus segment has a third end and a fourth end, the outer stent body is connected to the third end, and the first connection end is located at the fourth end; Wherein, in the axial direction of the valve stent, the third end is located between the first end and the first connection end.

6. The valve stent according to claim 3 or 5, characterized in that, The outer stent body is configured as a spherical shape with an opening, the structure of the outer stent body abuts against the atrial wall, the outer valve annulus segment is located at the opening, and the outer valve annulus segment is located at the valve annulus position.

7. The valve stent according to claim 2 or 4, characterized in that, The distance between the third end and the fourth end of the outer valve annulus segment is L1, L1 is not less than the axial length of the valve annulus, and L1 satisfies the relationship: 1 mm ≤ L1 ≤ 15 mm.

8. The valve stent according to claim 1, wherein The connecting frame includes at least one connecting rod, and at least one of the connecting rods is connected between the first connection end and the second connection end. The width of the connecting rod is W, satisfying the relational expression: 0.1 mm ≤ W ≤ 2.5 mm; Preferably, the width of the connecting rod is greater than the width of the support rod of the outer support, so that the toughness of the outer support is less than the toughness of the connecting rod; Preferably, the width of the connecting rod is greater than the width of the support rod of the inner support, so that the rigidity of the inner support is greater than the rigidity of the connecting rod; Preferably, the distance difference is L2, and L2 satisfies the relational expression: L2 ≤ 25 mm; Preferably, a plane perpendicular to the inner support is set as a reference plane, and the angle between the connecting frame and the reference plane is α, and α satisfies the relational expression: 2° ≤ α ≤ 80°; Preferably, the connecting frame includes: a connecting section and a transition section. The transition sections are respectively connected to both sides of the connecting section. One of the transition sections is connected to the first connection end and the other transition section is connected to the second connection end; wherein, the connecting section is at least one of an arc structure, an S-shaped structure, a wavy structure, a V-shaped structure, and a grid-like structure; and / or the transition section is at least one of a circular arc structure, a straight rod structure, a single rod structure, a multi-rod structure, and a grid-like structure.

9. The valve stent according to claim 1, wherein The outer support, the inner support, and the connecting frame are integrally formed.

10. A valve prosthesis, characterized in that, Comprising: The valve stent, leaflets, and suture membrane according to any one of claims 1-9; The leaflets are connected to the inner support of the valve stent; The suture membrane is disposed on the inner support and the outer support of the valve stent.

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