A heart valve stent and prosthesis thereof

Abstract

The present invention discloses a heart valve stent and prosthesis thereof. The stent comprises a stent frame comprising a plurality of interconnected grids, with multiple end grids at both ends of the stent frame, at least one of which is a first end grid. All end grids at the end where the first end grid is located are continuously and completely distributed in the circumferential direction, and the axial projection height of the first end grid is lower than the axial projection heights of the other end grids at the same end. The heart valve stent and prosthesis provided by the present invention can reduce damage to the conduction system and reduce conduction block, thereby improving surgical safety and the patient's quality of life.

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] The human heart has four valves: the aortic valve, the pulmonary valve, the mitral valve, and the tricuspid valve. These valves function as one-way valves, opening and closing rhythmically as the heart rhythmically contracts and relaxes. This allows blood to flow smoothly through the valve openings and prevents backflow, thereby maintaining the proper function of the circulatory system. Inflammation of the heart valves can cause structural damage, fibrosis, adhesions, shortening, myxomatous degeneration, ischemic necrosis, and calcium deposits. Congenital malformations can also cause valve lesions, impairing normal blood circulation, a condition medically known as valvular heart disease. Aortic stenosis (AS), caused by degenerative changes in the aortic valve, occurs in up to 10% of patients over the age of 65, with calcific aortic stenosis (CAS) being the most common type.

[0003] Heart valve intervention is a rapidly developing medical technology in recent years. Its principle is to implant a valve prosthesis into the original valve position through the apex or blood vessels in a minimally invasive manner to replace the original valve, ultimately achieving the goal of treating the patient. This surgery has the characteristics of minimal trauma, rapid recovery, and low risk, making it particularly suitable for elderly patients with heart valve problems. Transcatheter aortic valve implantation (TAVI) is a type of heart valve intervention treatment for aortic valve disease, which is mainly used to treat heart valve diseases such as aortic stenosis and aortic regurgitation.

[0004] Currently, two major types of aortic valve stent systems are in clinical use: one with a rigid material as the main structure and requiring balloon expansion for release; the other with a memory metal as the main structure and self-expanding for in vivo release. Balloon-expandable stents are implanted transapically, while self-expanding stents are implanted via a peripheral vascular route. Peripheral vascular implantation is less invasive, resulting in a faster recovery, making it more popular. Furthermore, self-expanding stents offer the advantages of being adjustable and retrievable compared to balloon-expandable stents. However, the greatest advantage of balloon-expandable stents is their lower incidence of atrioventricular block. Conversely, the incidence of permanent pacemaker placement is significantly higher in patients implanted with self-expanding stents than with balloon-expandable stents.

[0005] Clinical studies have demonstrated that direct compression of the aortic valve stent on the conduction system is the most critical factor in the development of new conduction disorders after TAVI surgery. The incidence of conduction disorders is significantly lower in balloon-expandable stents implanted in very short lengths of the left ventricular outflow tract, compared to self-expanding valve stents implanted in the left ventricular segment, which can be as long as 4-6 mm. In fact, for the same self-expanding valve stent implanted, the deeper the implant into the left ventricle, the more likely it is to develop conduction block after surgery. However, because the high blood pressure during left ventricular pulsation exerts a significant impact on the stent and valve, the stent must be securely anchored and have a strong radial support force. Otherwise, it can easily cause stent migration, collapse, paravalvular leakage, and even loss of function. Currently, to ensure that the aortic valve stent has sufficient radial support, a dense and circumferentially complete grid configuration is generally used for the inflow tract.

[0006] Existing self-expanding aortic valve stent systems are prone to damaging the conduction system, leading to conduction block, severe complications, and even death. Therefore, mitigating conduction block with self-expanding aortic valve stent systems is an urgent issue that needs to be addressed. This is crucial for promoting this technology and improving patients' quality of life. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a heart valve stent and a prosthesis thereof, which can reduce damage to the conduction system, reduce conduction block, and thus improve surgical safety and the quality of life of patients.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is to provide a heart valve stent, wherein the stent includes a stent frame, the stent frame includes a plurality of interconnected grids, the two ends of the stent frame have a plurality of end grids, at least one end grid is a first end grid, all end grids of the end where the first end grid is located are continuously and completely distributed in the circumferential direction, and the axial projection height of the first end grid is lower than the axial projection heights of other end grids at the same end.

[0009] Preferably, the end of the first end grid is rolled inwardly toward the axial direction of the stent to form an inwardly rolled grid.

[0010] Preferably, in a plane defined by the outline of the inward-rolling grid and the axis of the stent, the inward-rolling angle γ of the inward-rolling grid has a value range of 90°≤γ≤270°.

[0011] Preferably, a vertical distance L from the center of the curled portion of the inward-rolling grid to the outline element line is greater than or equal to the arc radius R, wherein the arc radius R of the curled portion is constant or variable.

[0012] Preferably, the end of the first end grid is folded inward or concave toward the axis of the bracket to form an inward folded grid or a concave grid, and the inward folded grid has a bending portion, and the outline of the bending portion is an arc, a straight line, a broken line or a combination thereof.

[0013] Preferably, in a plane defined by the outline of the inward-folded grid or the inward-concave grid and the axis of the stent, the value range of the inward-concave angle α or the inward-folding angle β is 10°≤α / β≤80°.

[0014] Preferably, the shape of the first end grid is a quadrilateral, all four sides of which are formed by wave bars, and the length of two adjacent wave bars forming the end is smaller than the length of the wave bars on the other two sides.

[0015] Preferably, a value range of a projected height difference H between the first end grid and other end grids at the same end in the axial direction is 0 mm < H ≤ 12 mm.

[0016] Preferably, the projection height difference H has a value range of 2 mm ≤ H ≤ 4 mm.

[0017] Preferably, the angle θ of the first end grids distributed along the circumference of the bracket is in the range of 20°≤θ≤120°.

[0018] Another technical solution adopted by the present invention to solve the above technical problem is to provide a heart valve prosthesis, which includes the above heart valve stent and a valve structure, wherein the valve structure is arranged in the stent frame of the heart valve stent.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the heart valve stent and prosthesis provided by the present invention have a lower axial projection height of at least one first end grid than the axial projection height of the other end grids at the same end. When in use, the position of the first end grid with a shorter axial projection height corresponds to the position of the native valve ring conduction bundle, avoiding contact between the stent end and the conduction bundle and reducing the risk of conduction block. Compared with traditional stents with circumferential notches, the heart valve stent and prosthesis of the present invention have a higher radial support force, while meeting the radial support force and reducing the risk of conduction block. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1a 、 1b 1 and 1c are schematic diagrams of the overall structures of three different shapes of existing heart valve stents;

[0021] Figure 2a 、 2b This is a schematic structural diagram of the end grid of the heart valve stent in an embodiment of the present invention rolled inward to form an arc shape;

[0022] Figure 2c This is a schematic diagram of an embodiment of the present invention in which the end grid of the heart valve stent is rolled inward to form an arc shape and a height difference is formed in the axial direction;

[0023] Figure 3a This is a front view of the end grid of the heart valve stent in an embodiment of the present invention rolled inward to form an arc shape;

[0024] Figure 3b A side view of the end grid of the heart valve stent in an embodiment of the present invention rolled inward to form an arc shape;

[0025] Figure 3c A side view of the end grid of the heart valve stent in an embodiment of the present invention rolled inward to form an arc shape;

[0026] Figure 3d Schematic diagram of the inward rolling angle of the end grid of the heart valve stent in an embodiment of the present invention to form an arc shape;

[0027] Figure 4a Schematic diagram of a first end portion of a heart valve stent according to an embodiment of the present invention, wherein the grid is folded inwardly into an arc shape;

[0028] Figure 4b Schematic diagram of a first end portion of a heart valve stent according to an embodiment of the present invention being folded into a broken line shape;

[0029] Figure 4c Schematic diagram of a first end portion of a heart valve stent according to an embodiment of the present invention being folded into a straight line inwardly in a grid;

[0030] Figure 4d Schematic diagram of the grid concave angle of the first end portion of the heart valve stent in an embodiment of the present invention;

[0031] Figure 4e Schematic diagram of the inward folding angle of the grid at the first end portion of the heart valve stent according to an embodiment of the present invention;

[0032] Figure 5a This is a front view of a heart valve stent including a shorter first end grid in an embodiment of the present invention;

[0033] Figure 5b A side view of a heart valve stent including a shorter first end grid in an embodiment of the present invention;

[0034] Figure 6 Schematic diagram of the circumferential distribution of the grids of the first end portion of the heart valve stent in an embodiment of the present invention;

[0035] Figure 7a Schematic diagram of a heart valve prosthesis implanted into a human heart according to an embodiment of the present invention;

[0036] Figure 7b for Figure 7a A local enlarged schematic diagram of point A;

[0037] Figure 8 Schematic diagram of the support force test of the heart valve prosthesis in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings and examples.

[0039] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention can be practiced without these specific details. Therefore, the specific details set forth are merely exemplary, and the specific details may be varied within the spirit and scope of the present invention and still be considered to be within the spirit and scope of the present invention.

[0040] The heart valve stent provided in this embodiment can be used in aortic, mitral, tricuspid, or pulmonary valve stent systems. In addition to self-expanding stents, it can also be applied to other types of stents, such as balloon-expandable and mechanically expandable valve stents. The heart valve prosthesis provided by the present invention includes a heart valve stent and a valve structure. The heart valve stent includes a stent frame. Accordingly, the valve structure can also be radially expanded and compressed, and the valve structure is located within the stent frame. Figure 1a 、 1b 1c and 1c show three different shapes of stent frames for heart valve prostheses, wherein the main contours thereof are cylindrical or cylindrical-like shapes. Figure 1a The profile of the stent frame is cylindrical, Figure 1b The outline of the support frame is hourglass-shaped. Figure 1c The stent frame has a conical outline. Other cylindrical stent frame structures are also possible and are not limited here. The stent frame has a grid structure and can be compressed into a cylindrical lumen.

[0041] See Figure 2a-2c 、 Figure 4a-4c 、 Figure 5a and Figure 5b , this embodiment provides a heart valve stent, comprising: a stent frame 1, the stent frame 1 has an inflow channel 11 and an outflow channel 12 in the axial direction; according to the direction of blood flow, the outflow channel 12 is located downstream of the inflow channel 11. The inflow channel 11 corresponds to the part where blood flows into the heart valve stent when the valve prosthesis is operated, and the outflow channel 12 corresponds to the part where blood flows out of the heart valve stent when the valve prosthesis is operated. The stent frame 1 is composed of a plurality of interconnected grids, the grids are generally rhombus-shaped, and can also be other suitable shapes, such as pentagons, hexagons, etc., which can form a closed-shaped unit; the grids have grid edge wave rods and nodes, the grid edge wave rods are rods that form the grid, and the nodes are connection points formed by connecting at least two grid edge wave rods. There are multiple end grids 13 at both ends of the stent frame 1, at least one end grid 13' is a first end grid, and all end grids at the end where the first end grid is located are continuously and completely distributed in the circumferential direction; that is, all end grids 13 at the end where the first end grid 13' is located are continuously distributed in the circumferential direction, without missing grids, so as not to affect the radial support force; such as Figure 2a-2c 、 Figure 4a-4c As shown, the end 131 of the first end grid 13' is bent toward the axis of the stent, so that the axial projection height of the first end grid 13' is lower than the axial projection height of the other end grids 13 at the same end; or as shown Figure 5a and Figure 5b As shown, the two grid edge bars of the first end grid 13' are shortened so that the axial projection height of the first end grid 13' is lower than the axial projection heights of the other end grids at the same end. The stent axis is the straight line on which the central axis of the stent frame 1 is located, and the direction along the stent axis is the axial direction.

[0042] In one embodiment, Figure 2a-2c 、 Figure 4a-4cAs shown, the end 131 of the first end grid 13' is rolled, folded, or concave inward toward the axis of the stent, forming an inward-rolled grid, an inward-folded grid, or an inward-concave grid. The final contour formed by the bent portion of the inward-rolled grid, the inward-folded grid, or the inward-concave grid can be an arc, a straight line, a broken line, or a combination of these shapes. The end of the inward-rolled grid, the inward-folded grid, or the inward-concave grid has the characteristic of converging toward the axis of the stent. Alternatively, two of the grid edge wave bars constituting the first end grid 13' can be shortened, so that the shortened first end grid 13' forms a height difference in the axial direction with the other end grids at the same end. See [referring to] Figure 5a and 5b Taking the diamond grid as an example, the length of the two adjacent wave rods L1 and L2 constituting the end node in the first end grid 13' is shorter than the length of the wave rods L3 and L4 on the other two sides, forming a shorter end grid; the other end grids are diamond structures, and the lengths of the wave rods constituting the four sides of the diamond grid are equal to the lengths of the long-side wave rods L3 and L4 of the shorter end grid. Therefore, the shorter first end grid 13' forms an axial height difference with the other end grids 13 at the same end, but the shorter first end grid 13' is still a closed grid and does not affect the radial support force. The ends 13' of these first end grids are rolled inward, folded inward, concave inward, or the wave rods constituting the first end grid 13' are shortened, so that they form an axial projection distance difference H with the other end grids at the same end, as shown in FIG. Figure 2c shown.

[0043] Accordingly, the end 131 of the first end grid 13' described in this embodiment refers to the tip of the grid structure at the end point of the stent frame's outline. In this embodiment, a generatrix is defined as: a curved surface figure can be viewed as the trajectory of a moving line, and the moving line that forms the curved surface is called a generatrix. A prime line is defined as the line where the generatrix is located at any position on the curved surface. A contour prime line refers to a prime line that represents the macroscopic outline on the projection surface.

[0044] In one embodiment, see Figure 2a-2c and Figure 3a-3d , part or all of the end grids 13 at the same end are rolled inwards into an arc shape in the direction of the stent axis, forming an inward rolling grid. The so-called inward rolling means that within the plane where the outline and the stent axis are located, the tip of the first end grid 13' is rolled in the direction of the stent axis according to a certain radius around the axis perpendicular to the plane. Figure 3a As shown or only the inward curling part forms an arc as shown Figure 3b As shown, the principle is similar to the hem of a sheet metal part. The shape of the inward curled tail is not limited and can be shaped according to needs. In some embodiments, the inward curled portion of the inward curled grid can be set as a constant diameter arc or a combination of multiple arcs with varying diameters; the vertical distance from the center of the inward curled portion to the outline is L, and the arc radius is R, then L ≥ R, where the radius R can be constant or varying. Figure 3a 、 3b , 3c and 3d, where Figure 3a The dotted line in the figure represents the axis of the involution center. Figure 3b The dotted line in the figure is the outline of the involute grid. Within the plane bounded by the outline and the axis of the stent frame 1, the angle formed by the outline and the direction of the tangent line at the end of the curled arc is the involute angle γ, which is the rotation angle formed from the starting point to the end point of the involute. The value range of γ is 0.1°≤γ≤360°; preferably 31°≤γ≤270°, which has the advantage of easy manufacturing; more preferably 90°≤γ≤270°, in which case the imaging area of the involute part is more concentrated, which is more conducive to observation by the operator, and achieves accurate positioning, precise fine-tuning, or valve stent recovery. Please refer to Figure 2c The axial projection distance between the end of the inward-rolled grid and the end of the other end grid at the same end, that is, the axial projection distance difference H between the inward-rolled grid and the other end grid at the same end, has a value range of 0mm<H≤12mm, preferably 1≤H≤6mm, and more preferably 2≤H≤4mm.

[0045] In another embodiment, the end 131 of at least one end grid 13 is folded inward or concave inward toward the axis of the stent, forming an inward-folded grid or a concave-folded grid. The inward-folding refers to the first end grid 13' being bent toward the axis of the stent at a certain point on the grid edge, and the tip of the first end grid 13' is close to the axis of the stent; the concave refers to the first end grid 13' being concave toward the axis of the stent at a certain point on the grid edge, and the concave part is close to the axis of the stent; see 4e, the inward-folded grid has a bending portion, which is the portion from the bending point 132 to the end 131 of the inward-folded grid, and the outline of the bending portion is an arc, a straight line, a broken line, or a combination thereof. Specifically, see Figure 4a The first end grid 13' is folded inwardly toward the axis of the stent and the outline of the bent portion is an arc. Figure 4b The first end grid 13' is folded inwardly toward the axis of the stent and the outline of the bent portion is in the shape of a broken line. Figure 4c , the first end grid 13 'is folded inwardly toward the axis of the stent and the outline of the bent portion is a straight line. In another embodiment, see Figure 4d The contour line of the first end grid 13', which is bent inwardly toward the axis of the stent, is a broken line. The bent part is the portion from the bending point 132 to the end 131 of the inwardly bent grid. When an inward fold is adopted, the contour line of the bent part can be an arc, a straight line, a broken line, or a combination thereof; an arc or a straight line is preferred, as it is easy to process and manufacture. In the plane defined by the contour line and the axis of the stent frame 1, the range of the inward angle α and the inward folding angle β of the first end grid 13' is 0.1°≤α / β≤180°. Please refer to Figure 4d The concave angle α is the angle between the contour line 133 before concave and the line connecting the inflection point 132 of the grid and the end 131 of the grid; see Figure 4e The inward folding angle β is the angle between the outline line 133 of the grid before folding inward and the line connecting the grid bending point 132 and the end 131 of the grid. The value range of the inward concave angle α and the inward folding angle β is preferably 10°≤α / β≤80°, which has the advantage of convenient production and manufacturing.

[0046] Of course, those skilled in the art may use one or more combinations of rolling, folding, concave or shortening the wave rods constituting the end grid for the first end grid 13' to form an end grid with a shorter projection in the axial direction. This embodiment does not impose any particular limitation on this.

[0047] Figure 6 The distribution area of the first end grid 13' in the circumferential direction, taking the inflow tract projection of a cylindrical stent as an example, the distribution angle θ formed by the first end grids 13' in the circumferential direction can be in the range of 20°≤θ≤120°, with θ preferably being 90°. After the heart valve stent is implanted, the distribution area of the first end grids 13' corresponds to the part where the conduction bundle is concentrated in the heart anatomical structure, avoiding compression of the conduction bundle. Figure 7a and Figure 7b It can be seen that this setting significantly avoids compression of the conduction bundle, thereby reducing the probability of conduction block.

[0048] In the prior art, to avoid compression of the conduction bundle, a notch is provided on the heart valve stent frame at the position corresponding to the conduction bundle. This can be achieved by removing the wave rods of the end grid at the corresponding position to achieve a partial end grid loss. This will destroy the radial support force of the stent and easily cause the stent to deform or even collapse. This design is not suitable for the aortic valve system because the blood flow pressure and cardiac pulsation pressure that the aortic valve stent needs to withstand are significantly increased, which puts greater radial support force on the stent. Test experiments have shown that compared with the traditional grid loss, the support force of the stent frame of the heart valve stent provided by the present invention is significantly better than that of the grid loss stent.

[0049] See Figure 8 The COF (Chronic Outward Force) that the two stent frames can withstand at the first node of the end grid was measured. The larger the value, the better the circumferential support force. Among them, the "notched stent" represents the existing stent with a notch; the "inward-rolled stent" represents the stent provided by the present invention. The experimental results show that the supporting force of the heart valve prosthesis stent provided by the present invention is significantly better than that of the stent with a grid-missing stent.

[0050] Experimental Method: The notch or inward roll of the tested stent was set at the end of the stent. The notch or inward roll structure was measured in two ways: with the structure facing upward and with the structure facing the tester (with the structure facing outward). The test results are as follows:

[0051]

[0052] It can be seen from the above table that the COF force that the inward-rolled stent provided by the present invention can withstand at the first node of the end grid is significantly greater than the COF force that the existing notched stent can withstand at the first node of the end grid. Therefore, the supporting force of the heart valve prosthesis stent provided by the present invention is significantly better than the supporting force of the grid-missing stent.

[0053] In summary, the heart valve stent and prosthesis provided by the present invention, by inwardly rolling, folding, concave the ends of part of the end grids or shortening the wave rods constituting the end grids so that the position corresponds to the position of the native valve ring conduction bundle, a height difference is formed relative to the position of the conduction bundle, thereby reducing the risk of conduction block. Compared with the traditional notched grid structure setting, the local radial support force of the valve ring is relatively high, which achieves the goal of reducing the risk of conduction block while meeting the radial support force. At the same time, when it is in the form of inward rolling, folding, or concave, the contact position between the stent and the tissue is a blunt end, which further avoids compression and contusion of the tissue and the conduction bundle. In addition, the inward rolling of the end grid end will make the imaging area more concentrated or increased, which is more conducive to the observation of the surgical operator, accurate positioning, precise fine-tuning or recovery of the valve stent.

[0054] 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, characterized in that: The bracket includes a bracket frame, which includes multiple interconnected grids. Both ends of the bracket frame have multiple end grids, at least one end grid is a first end grid, all end grids at the end where the first end grid is located are continuously and completely distributed in the circumferential direction, the axial projection height of the first end grid is lower than the axial projection heights of other end grids at the same end, the end of the first end grid is rolled inward toward the axis of the bracket to form an inward rolling grid, and in the plane defined by the outline of the inward rolling grid and the axis of the bracket, the inward rolling angle γ of the inward rolling grid has a value range of 90°≤γ≤270°, and the value range of the axial projection height difference H formed between the first end grid and the other end grids at the same end is 0mm<H≤12mm.

2. The heart valve stent according to claim 1, wherein The vertical distance L from the center of the curled part of the inward-rolling grid to the outline element line is greater than or equal to the arc radius R, wherein the arc radius R of the curled part is a constant diameter or a variable diameter.

3. The heart valve stent according to claim 1, wherein: The shape of the grid at the first end is a quadrilateral, the four sides of which are all formed by wave rods, and the length of two adjacent wave rods forming the end is smaller than the length of the wave rods at the other two sides.

4. The heart valve stent according to claim 1, wherein: The projection height difference H has a value range of 2 mm ≤ H ≤ 4 mm.

5. The heart valve stent according to claim 1, wherein: The angle θ of the first end grid distributed along the circumference of the bracket is in the range of 20°≤θ≤120°.

6. A heart valve stent, characterized in that: The bracket includes a bracket frame, which includes multiple interconnected grids. Both ends of the bracket frame have multiple end grids, at least one end grid is a first end grid, all end grids at the end where the first end grid is located are continuously and completely distributed in the circumferential direction, the axial projection height of the first end grid is lower than the axial projection height of other end grids at the same end, the end of the first end grid is folded inward or concave toward the axis of the bracket to form an inward folded grid or an inward concave grid, the inward folded grid has a bending portion, the contour line of the bending portion is an arc, a straight line, a broken line or a combination thereof, in the plane defined by the contour line of the inward folded grid or the inward concave grid and the axis of the bracket, the value range of the inward concave angle α or the inward folding angle β is 10°≤α / β≤80°, and the value range of the axial projection height difference H formed between the first end grid and the other end grids at the same end is 0mm<H≤12mm.

7. The heart valve stent according to claim 6, wherein: The shape of the grid at the first end is a quadrilateral, the four sides of which are all formed by wave rods, and the length of two adjacent wave rods forming the end is smaller than the length of the wave rods at the other two sides.

8. The heart valve stent according to claim 6, wherein: The projection height difference H has a value range of 2 mm ≤ H ≤ 4 mm.

9. The heart valve stent according to claim 6, wherein: The angle θ of the first end grid distributed along the circumference of the bracket is in the range of 20°≤θ≤120°.

10. A heart valve prosthesis, characterized in that: It comprises the heart valve stent and valve structure according to any one of claims 1 to 9, wherein the valve structure is arranged in the stent frame of the heart valve stent.

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