Forming method of high-molecular artificial heart valve

Abstract

The invention provides a forming method of a high-molecular artificial heart valve, which comprises the following steps of: wrapping a skirt on the surface of a bracket, placing one part of a valve leaflet on the surface of at least one part of the skirt or butting the edge of the valve leaflet with at least one part of the skirt, and bonding the valve leaflet and the edge of the skirt together by utilizing an interface micro-processing mode, so as to obtain the high-molecular artificial heart valve. The interface microprocessing is achieved by means of a second polymer solution bonding the edges of the leaflet and the skirt or by means of thermal bonding between the leaflet and the skirt. By adopting the forming mode, the valve leaflet and the skirt can be prepared by selecting different polymers according to actual requirements, and the width of the bonding area is adjustable; and the bonding process can be carried out by means of the clamping mold, so that the positions of the skirt edge and the valve are fixed, accurate bonding is facilitated, it is guaranteed that the manufactured valve is more uniform in structure and higher in strength, and the production quality of the valve is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a forming method of a polymer artificial heart valve. Background Art

[0002] Transcatheter artificial heart valve replacement is an effective minimally invasive surgical procedure for treating structural heart valve diseases. Compared with traditional open-chest surgical valve replacement, this surgical procedure has significant advantages such as less trauma, shorter operation time, and faster postoperative recovery, so it has been promoted very quickly. The artificial valve prosthesis used in this replacement procedure includes artificial valve leaflets, a metal stent, and an anti-peripheral leakage skirt. Among them, the valve leaflets and the stent are combined through an attachment edge, and the skirt completely covers the stent. The valve leaflet material of interventional artificial heart valves is mainly animal-derived tissues such as bovine pericardium, porcine pericardium, and porcine heart valves. It not only has high costs, but also is difficult to control the material consistency. At the same time, due to the structural characteristics of animal-derived tissues, such valve leaflets can only be attached to the metal stent by manual suture, which requires a lot of labor costs. The average sewing time of commercially available interventional artificial valves on the market is about 3 days, and the technical level requirements for valve sewing workers are extremely high. In addition, the method of manually sewing valves will make it difficult to control the product quality and reduce the product consistency.

[0003] Polymer (polymer) valve leaflets with excellent durability, compatibility, and stability are considered to be used in the manufacture of the next generation of interventional artificial heart valves. In the process of making artificial heart valves using polymer valve leaflets, it is usually in two ways: integral dip coating valve forming, or first preparing valve leaflets and skirts, and then combining the two for processing and forming. The valve obtained by integral dip coating is an integrally formed structure, and its preparation efficiency is high, but it is impossible to selectively choose corresponding materials according to the usage requirements. After separately preparing the valve leaflets and skirts and then combining the two by suture, it is easy to cause problems such as inflammation, hyperplasia, and calcification at the suture position.

[0004] In view of this, it is necessary to design an improved forming method of a polymer artificial heart valve to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a forming method of a polymer artificial heart valve.

[0006] To achieve the above invention purpose, the present invention provides a forming method of a polymer artificial heart valve, including the following steps:

[0007] Prepare a skirt on the stent;

[0008] Place a part of the leaflet on the surface of at least a part of the skirt or make the edge of the leaflet dock with at least a part of the skirt, where both the leaflet and the skirt are made of polymer materials; bond the edges of the leaflet and the skirt together by means of interface micro-treatment, and obtain the polymer artificial heart valve after drying.

[0009] The interface micro-treatment bonds the edges of the leaflet and the skirt by means of a second polymer solution or realizes it by thermal bonding between the leaflet and the skirt.

[0010] When placing a part of the leaflet on the surface of at least a part of the skirt, the leaflet and the skirt will come into contact with each other. The interface micro-treatment method can be selected to bond the edges of the leaflet and the skirt by means of a second polymer solution or realize it by thermal bonding between the leaflet and the skirt.

[0011] In the present invention, "docking" means that the edge of the leaflet is aligned with at least a part of the skirt but does not contact each other. For this case, the interface micro-treatment method is to bond the edges of the leaflet and the skirt by means of a second polymer solution.

[0012] Preferably, the method for preparing the skirt on the stent includes the following steps: immerse the stent in a first polymer solution with a mass percentage of 10-20%, perform dip coating and pulling at a pulling speed of 1000-1200 mm / s, dry at a temperature of 50-60 °C for 4-5 h, then perform secondary dipping, and after drying at 50-60 °C for 48-60 h after the dipping is completed, the skirt is obtained on the surface of the stent.

[0013] Preferably, the method for bonding the leaflet and the skirt with the second polymer solution is one or several of solution dipping method, solution dispensing method, and solution spraying method; the thermal bonding method is one or several of thermal welding method, laser welding method, and infrared welding method; the width of the bonding area between the leaflet and the skirt is 1000-1200 μm.

[0014] Preferably, the method for preparing the skirt on the stent includes directly forming a skirt integrally connected to the stent on the stent by dipping method or fixing a pre-made skirt on the stent.

[0015] Preferably, when using the solution dipping method or the solution dispensing method to bond the leaflet and the skirt, the viscosity of the second polymer solution is 300-300000 centipoise, the solid content of the solution is 5-30%, and the pulling speed during the dipping process is 1-10000 μm / s; preferably, the viscosity is 5000-20000 centipoise, the solid content of the solution is 10-20%, and the pulling speed is 500-2000 μm / s.

[0016] Preferably, when using the solution dispensing method, the dispensing pressure is 40 - 60 psi; when using the solution spraying method, the viscosity of the second polymer solution is 1 - 100 cP, and the solid content of the solution is 1 - 20%. Preferably, the viscosity of the second polymer solution is 5 - 50 cP, and the solid content of the solution is 3 - 8%.

[0017] Preferably, the material of the skirt is one or more of polyethylene terephthalate, polyurethane, and polyolefin - polyethylene terephthalate blended fabric; the material of the leaflet is one or more of polyurethane and its fiber - reinforced materials, styrene - isobutylene - styrene copolymer and its cross - linked products, styrene - butadiene - styrene copolymer and its cross - linked products, silicone rubber, and polytetrafluoroethylene.

[0018] Preferably, the process of bonding the leaflet and the skirt is carried out with the aid of a clamping mold. The clamping mold includes a support member for supporting the stent. The support member includes a cylinder with a smooth outer wall. One end of the cylinder is provided with a plurality of concave areas, and the shape formed by the outer walls of the plurality of concave areas is adapted to the shape of the natural leaflet in the open or closed state. A reference line is provided on the outer wall of the cylinder for providing a reference for the alignment of the stent and the support member.

[0019] Preferably, the clamping mold further includes a fixing member sleeved outside the support member. The fixing member includes a base and a plurality of protrusions evenly arranged on the base. The base is a circular ring, and the protrusions protrude outward along the central axis direction of the base. The edge lines of all the protrusions away from the base together form a positioning line. After the fixing member is sleeved outside the support member, the reference line and the positioning line coincide.

[0020] Preferably, the material of the clamping mold is a metal material, a rigid polymer material, or a soft polymer material.

[0021] In particular, the above - mentioned method can be used to prepare a polymer artificial heart valve.

[0022] The beneficial effects of the present invention are as follows:

[0023] The molding method of the polymer artificial heart valve provided by the present invention is as follows: after preparing a skirt on the stent, a part of the valve leaf is placed on the surface of at least a part of the skirt or the edge of the valve leaf is docked with at least a part of the skirt, and then the edge of the valve leaf and the skirt are bonded together by means of interface micro-treatment to obtain an artificial heart valve. During this process, according to the actual application requirements, the width of the bonding area can be adjusted to prepare artificial heart valves with different performances. In addition, during the process of bonding the valve leaf and the skirt together, a clamping mold can also be used to fix the skirt and the valve leaf to ensure that their edges are aligned with each other, which is conducive to achieving precise bonding and ensuring that the manufactured valve has a more uniform structure and higher strength. At the same time, the clamping mold can also prevent the polymer solution from dissolving the skirt and / or the valve leaf during the bonding process, causing damage to the skirt and the valve leaf and affecting the production efficiency of the valve. Secondly, in the process of realizing valve molding by means of interface micro-treatment, different polymers can be selected to prepare the valve leaf and the skirt according to actual needs. The material requirements for the valve leaf and the skirt are low, and valves with different materials and compositions can be manufactured, so it has better universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic diagram of the positional relationship between the stent and the support member and the structure of the fixing member during the preparation of the polymer artificial heart valve in Example 1 of the present invention;

[0025] Figure 2 is Figure 1 a schematic diagram of the structure of the support member in FIG. from one angle;

[0026] Figure 3 is Figure 2 a schematic diagram of the structure of the support member in FIG. from another angle;

[0027] Figure 4 is Figure 1 a schematic diagram of the structure of the fixing member in FIG.

[0028] The reference numerals are as follows:

[0029] 10, support member; 101, reference line; 20, stent; 30, fixing member; 31, base; 32, convex block. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, and other details less related to the present invention are omitted.

[0032] In addition, it should be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or apparatus.

[0033] The forming method of the polymer artificial heart valve provided by the present invention is as follows in the specific preparation process:

[0034] After preparing the skirt on the stent 20, a part of the leaflet is placed on the surface of at least a part of the skirt or the edge of the leaflet is docked with at least a part of the skirt, and then the edges of the leaflet and the skirt are bonded together by means of interface micro-treatment, and an artificial heart valve is obtained after drying.

[0035] When a part of the leaflet is placed on the surface of at least a part of the skirt, the leaflet and the skirt will come into contact with each other. The interface micro-treatment method can be selected to bond the edges of the leaflet and the skirt by means of a second polymer solution or to achieve thermal bonding between the leaflet and the skirt.

[0036] In the present invention, "docking" means that the edge of the leaflet is aligned with at least a part of the skirt but does not contact each other. In this case, the interface micro-treatment method is to bond the edges of the leaflet and the skirt by means of a second polymer solution.

[0037] Preferably, the interface micro-treatment method can be achieved by bonding the edges of the leaflet and the skirt by means of a second polymer solution or by using thermal bonding between the leaflet and the skirt. The second polymer solution can be an N,N-dimethylacetamide solution of polyurethane or a cyclohexane solution of SIBS. When it is an N,N-dimethylacetamide solution of polyurethane, the concentration is 10-20%, and when it is a cyclohexane solution of SIBS, the concentration is 10-20%. By bonding the leaflet and the skirt together in the above manner, the corresponding second polymer solution can be selected according to the materials of the skirt and the leaflet, and an artificial heart valve that meets the requirements of various use environments can be obtained.

[0038] Preferably, the method for preparing the skirt on the stent 20 includes directly forming a skirt integrally connected to the stent by an impregnation method, which specifically includes the following steps: After immersing the stent 20 in a dimethylacetamide solution of polyurethane with a mass percentage of 10-20%, the impregnation and lifting are carried out at a lifting speed of 1000-1200 mm / s. After impregnation, it is dried at a temperature of 50-60°C for 4-5 h, and then subjected to secondary impregnation. After the impregnation is completed, it is dried at 50-60°C for 48-60 h, and then a skirt can be obtained on the stent 20. The stent 20 has a number of meshes, and the shape of the meshes can be a rhombus or other shapes, and it only needs to be set according to the needs in the specific application process, and is not limited thereto.

[0039] In particular, in some embodiments, the method for preparing the skirt on the stent may also include preparing the skirt in advance and then fixing the skirt on the stent 20. The fixing methods include sewing, bonding, etc. The specific fixing method can be selected according to needs, as long as the skirt can be fixed on the stent 20, and this is not limited herein. Preferably, the material of the leaflet includes, but is not limited to, one or more of polyurethane (PU) and its fiber-reinforced materials, styrene-isobutene-styrene copolymer (SIBS) and its cross-linked products, styrene-butadiene-styrene copolymer (SEBS) and its cross-linked products, silicone rubber (Q), and polytetrafluoroethylene (PTFE).

[0040] Preferably, the solute of the first polymer solution for preparing the skirt is a polymer such as polyethylene terephthalate (PET), polyurethane (PU), etc.; in some embodiments, the skirt may also be a woven fabric of polyolefin-polyethylene terephthalate (PO-PET) or other polymer mixtures.

[0041] Preferably, the method of bonding the leaflet and the skirt together with the second polymer solution is one or more of solution dipping method, solution dispensing method, and solution spraying method, and the method of thermal bonding is one or more of thermal welding method, laser welding method, and infrared welding method. The width of the bonding area between the leaflet and the skirt is 1000 - 1200 μm. Those skilled in the art should understand that the width of the bonding area here is the bonding width between the leaflet and the skirt after the bonding operation is completed. This is because during the bonding process, part of the first polymer solution will flow, or due to repeated bonding operations, the bonding area between the leaflet and the skirt is larger than the area when the first polymer solution first contacts the skirt or the leaflet. When using the solution dipping method and the solution dispensing method to bond the leaflet and the skirt, the viscosity of the second polymer solution is 300 - 30000 centipoise, the solid content of the solution is 5 - 30%, and the lifting speed during the dipping process is 1 - 10000 μm / s. More preferably, the viscosity is 5000 - 20000 centipoise, the solid content of the solution is 10 - 20%, and the lifting speed is 500 - 2000 μm / s. When using the solution dispensing method, the dispensing pressure is 40 - 60 psi, and when using the solution dipping method, the dipping and lifting speed is 1000 - 1200 μm / s. It should be noted that during the bonding process, the same process can be continuously repeated multiple times to ensure that when bonding the leaflet and the skirt together with different concentrations / viscosities of the second polymer solution, the bonding thickness is approximately the same, ensuring the same strength of the finally obtained valve. For the second polymer solution containing volatile solvents, it should be dried before entering the next step. Similarly, for non-solvent-based second polymer solution systems such as photocuring and ultraviolet curing, it should wait until the polymer liquid is basically cured before entering the next step.

[0042] When the solution spraying method is adopted, the viscosity of the second polymer solution is 1-100 cP, and the solid content of the solution is 1-20%, more preferably, the viscosity is 5-50 cP, and the solid content of the solution is 3-8%. It should be noted that during the bonding process, multiple sprays can be carried out. For the solvent-evaporating type second polymer solution system, it is necessary to ensure that the solution is basically dry before the next spray after each spray; for the non-solvent type second polymer solution system such as photo-curing and ultraviolet curing, it is necessary to ensure that the polymer liquid is cured before the next step after each spray; the spraying process can be manually operated by hand or by using a spray platform with a visual recognition system.

[0043] The process of bonding the leaflets and the skirt can be realized by means of a clamping mold, which includes a support member 10 for supporting the stent 20; specifically, the support member 10 is a cylinder with a smooth outer wall, and its structure is adapted to the stent 20 to sleeved the stent 20 outside the support member 10. One end of the cylinder is provided with a plurality of recessed areas, and the shape surrounded by the outer walls of the plurality of recessed areas is adapted to the shape of the natural leaflet in the open or closed state, and the number of recessed areas matches the number of leaflets.

[0044] The clamping mold further includes a fixing member 30 sleeved outside the support member 10. The fixing member 30 includes a base 31 and a plurality of convex blocks 32 evenly arranged on the base 31. The number of convex blocks 32 matches the number of leaflets. The base 31 is a ring, and the convex blocks 32 protrude outward along the central axis direction of the base 31. The edge lines of all the convex blocks 32 away from the base 31 together form a positioning line. The shape of the fixing member 30 is adapted to the structure of the skirt. When the support member 10 and the fixing member 30 are sleeved together, the positioning line coincides with the reference line 101; the material of the clamping mold is metal materials such as stainless steel, hard polymer materials such as polyoxymethylene, polyethylene, and polytetrafluoroethylene, and soft polymer materials such as silicone rubber, natural rubber, and ethylene propylene diene monomer rubber.

[0045] Particularly, a reference line 101 is also provided on the outer wall of the support member 10. Its setting can provide a reference for the alignment of the stent 20 and the support member 10 when the stent 20 is sleeved on the support member 10, and use the reference line 101 to identify whether the stent 20 is installed at an appropriate position on the support member 10 to ensure that after the leaflets are laid on the support member subsequently, the edges of the leaflets and the skirt can be aligned; at the same time, when the fixing member 30 is sleeved on the support member 10, the positioning line coincides with the reference line 101. At this time, the coincidence degree between the two can be used to confirm whether the edges of the skirt and the leaflets are aligned, further improving the accuracy of bonding. In the above way, when bonding the leaflets and the skirt together, not only can the support member 10 and the fixing member 30 be used to fix the two, but also the fixing member 30 can be used to protect the skirt from being dissolved and damaged by the second polymer solution, so as to facilitate the precise bonding of the leaflets and the skirt.

[0046] The forming method of the polymer artificial heart valve of the present invention will be further described below in conjunction with specific embodiments:

[0047] Embodiment 1

[0048] In this embodiment, a polymer artificial heart valve was prepared. The leaflets and the skirt were bonded together by using a polyurethane / dimethylacetamide solution containing 20% by mass of polyurethane. The model of the dip-coating and pulling machine used in the preparation process was SYDC-100, and the brand was Shanghai Sanyan. The bonding process was realized by means of Figures 1 to 4 the clamping mold shown.

[0049] Specifically, the material of the above-mentioned clamping mold is stainless steel, and specifically includes a support member 10 and a fixing member 30 sleeved outside the support member 10; specifically, the support member 10 is a cylinder with a smooth outer wall, and its structure is adapted to the stent 20 to sleeve the stent 20 outside the support member 10. One end of the cylinder is provided with 3 concave areas, and the shape formed by the outer walls of the 3 concave areas is adapted to the shape of the natural leaflet in the open or closed state; the fixing member 30 includes a base 31 and 3 convex blocks 32 evenly arranged on the base 31. The base 31 is a circular ring, and the convex blocks 32 protrude outward along the central axis direction of the base 31. The structure of the convex blocks 32 is as Figure 4 shown. All the convex blocks 32 together form a "petal-shaped" structure, and the edge lines of all the convex blocks 32 away from the base 31 together form a positioning line. Further, a reference line 101 is also provided on the outer wall of the support member 10. The reference line 101 is the edge line of each concave area. The setting of the reference line 101 can provide a reference for the alignment of the stent 20 and the support member 10 when the stent 20 is sleeved on the support member 10, and use the reference line 101 to identify whether the stent 20 is installed at an appropriate position on the support member 10, which is beneficial for the edges of the leaflets and the skirt to be aligned when laying the leaflets on the support member 10 later; at the same time, when the fixing member 30 is sleeved on the support member 10, the positioning line and the reference line 101 coincide, and at this time, the edges of the skirt and the leaflets are aligned to ensure the accuracy of the bonding process. It should be noted that in some other embodiments, the convex blocks 32 can also be of other shapes, and the position of the reference line can also be adjusted as needed, as long as the leaflets can be fixed on the skirt surface of the support member, and this is not limited here.

[0050] The specific preparation method of the polymer artificial heart valve is as follows:

[0051] S1. Uniformly scrape and coat a 16% polyurethane solution on the surface of the PET fabric, and after drying, laser cut to obtain a fiber-reinforced leaflet of polyurethane. The thickness of the leaflet is 100 microns, and the size is adapted to the size of the stent 20;

[0052] The stent 20 was immersed twice in a polyurethane / N,N-dimethylacetamide solution with a mass percentage of 20%. The immersion parameters were as follows: at 25 °C, the immersion and lifting were carried out at a lifting speed of 1000 mm / s. After the first immersion, it was dried at 50 °C for 4 h, and then the next immersion process was carried out; after the second immersion was completed, it was dried at 50 °C for 48 h, and the stent 20 with a skirt was obtained; after two immersion processes, the skirt composed of the polyurethane film could uniformly cover the stent 20. The film thickness on the metal rod of the stent 20 could reach about 50 μm, and the film thickness between the diamond grids of the stent 20 could reach about 100 μm, which could ensure that the skirt remained intact during the process of the valve entering the delivery device and being used in the human body; among them, the stent 20 had a number of diamond grids, the bottom diameter of the diamond grid was 3.1 cm, and the height was 3.6 cm;

[0053] S2. The leaflets and the skirt were bonded together by means of solution dispensing. The specific process was as follows: After the stent 20 with a skirt was sleeved on the support member 10, the edges of the leaflets were laid on the surface of the skirt, so that a part of the leaflets overlapped with the skirt, and the leaflets were aligned according to the reference line 101 on the surface of the support member 10, so that the areas to be bonded of the leaflets and the skirt were aligned with each other. Then, the fixing member 30 was sleeved outside the support member 10, and the skirt and the leaflets were fixed by using a clamping mold, which could prevent the polyurethane skirt from being dissolved and damaged by the polymer solution used in the subsequent operations; then, in the continuous dispensing mode of a manual dispenser, the areas to be bonded of the leaflets and the skirt were bonded together by using a polyurethane N,N-dimethylacetamide solution, and the width of the bonding area between the two was 1000 μm; among them, the dispensing pressure during the dispensing process was 50 psi, and the dispensing needle tip slowly moved along the edge line of the leaflet during dispensing, so that the areas to be bonded of the leaflets and the skirt could both come into contact with the polyurethane dimethylacetamide solution. After the dispensing was completed, it was dried at 50 °C for 4 h, and then, the above-mentioned dispensing process was repeated, and then it was dried at 50 °C for 48 h to obtain a polymer artificial heart valve.

[0054] Example 2

[0055] In this example, a polymer artificial heart valve was prepared. The brand of the dispenser used in this example was Nordson, and the structures of the clamping mold and the stent 20 used were the same as those in Example 1, which will not be elaborated here. The specific preparation method included the following steps:

[0056] S1. 5 g of a polyurethane dimethylacetamide solution with a mass fraction of 12.5% was poured into a petri dish with a diameter of 10 cm, spread evenly, and then dried at 50 °C for 48 h. After forming a film, a three-piece integral leaflet with a thickness of 90 microns was obtained by laser cutting;

[0057] The stent 20 is immersed in a dimethylacetamide solution of polyurethane with a mass percentage of 20% for two times, the immersion parameters are 25°C, the pulling speed is 1000mm / s, and after one immersion, it is dried in a 50°C environment for 4h, and then the above steps are repeated for a second immersion. After the immersion, it is dried in a 50°C environment for 48h to obtain a stent 20 coated with a skirt. After two immersion processes, the skirt can be evenly coated on the stent 20, the film thickness on the metal rod of the stent 20 can reach about 50μm, and the film thickness between the rhombus grids of the stent 20 can reach about 100μm, which can ensure that the skirt remains intact during the use of the valve delivery device and in the human body;

[0058] S2. Use solution dispensing to bond the leaflet and the skirt together. The specific process is as follows: After the bracket 20 covered with the skirt is sleeved on the support 10, the leaflet is laid on the support 10, and the leaflet is aligned according to the reference line 101 on the surface of the support 10, so that the edge of the leaflet is butted against the skirt, that is, the areas to be bonded of the leaflet and the skirt are aligned with each other under the support of the support 10 but do not contact each other, and then the fixing part 30 is sleeved on the outside of the support 10, and the skirt and the leaflet are fixed by a clamping mold, while avoiding the polymer solution used when the polyurethane skirt is bonded in subsequent operations. Dissolving damage; then, a glue sprayer with a visual recognition system is used to identify and determine the glue dispensing path, and then a second polymer solution (18% by mass of N, N-dimethylacetamide solution of polyurethane) is used to bond the leaflets and the skirt together. The width of the bonding area between the two is 1200μm, wherein the glue dispensing path width is 1000μm. During glue dispensing, the edges of the leaflets and the skirt can contact the second polymer solution. After one glue dispensing is completed, it is at 50°C for 4h, and then the above glue dispensing process is repeated, and then it is dried at 50°C for 48h to obtain a polymer artificial heart valve.

[0059] Example 3

[0060] This embodiment prepares a polymer artificial heart valve. The structures of the clamping mold and the stent 20 used are the same as those in Embodiment 1, and will not be repeated here. The specific preparation method includes the following steps:

[0061] S1. Pour 5 g of 20% by mass SIBS / cyclohexane solution into a culture dish with a diameter of 10 cm, spread it evenly and dry it at 50°C for 48 hours. After forming the film, laser cutting is used to obtain a three-piece integral leaflet with a thickness of 140 μm; the skirt is made of PET woven material;

[0062] S2. Directly sew the skirt on the stent 20 using PTFE suture, with the edge of the sewing position attached to the edge of the valve leaflet; place the valve leaflet on the surface of the skirt, and then cover a layer of room-temperature curable silicone sealant on both the inside and outside of the valve leaflet. Let the sealant dry at room temperature for 2 h, and then carry out the bonding operation. The specific process of bonding is as follows: After sleeving the stent 20 with the skirt sewn on it onto the support member 10, lay the edge of the valve leaflet on the surface of the skirt, so that a part of the valve leaflet overlaps with the skirt, and align the valve leaflet according to the reference line 101 on the surface of the support member 10 to make the bonding area between the valve leaflet and the skirt align with each other. Then, sleeve the fixing member 30 outside the support member 10, and use the clamping mold to fix the skirt and the valve leaflet, while avoiding the polyurethane skirt being dissolved and damaged by the polymer solution used during bonding in subsequent operations; Next, immerse the clamping mold with the valve leaflet and the skirt fixed as a whole into a 20% (mass percentage) SIBS / cyclohexane solution, with an impregnation and lifting speed of 1000 μm / s. After the impregnation, keep it at 50 °C for 4 h. Then, repeat the above impregnation process, and then dry it at 50 °C for 48 h to obtain a polymer artificial heart valve. The width of the bonding area between the valve leaflet and the skirt in the valve is 1000 μm.

[0063] Example 4

[0064] In this example, a polymer artificial heart valve was prepared. The structure of the clamping mold used is the same as that in Example 1, except for the support member 10. The structure of the support member 10 is basically the same as that in Example 1, which will not be elaborated here. The specific preparation method includes the following steps:

[0065] S1. Uniformly scrape a 16% polyurethane solution on the surface of the PET fabric, and after drying, cut it by laser to obtain a fiber-reinforced valve leaflet made of polyurethane. The thickness of the valve leaflet is 90 microns; Immerse the stent 20 twice in a 20% (mass percentage) polyurethane / N,N-dimethylacetamide solution. The impregnation parameters are as follows: at 25 °C, carry out impregnation and lifting at a lifting speed of 1000 mm / s. After the first impregnation, dry it at 50 °C for 4 h, and then carry out the next impregnation process; After the second impregnation is completed, dry it at 50 °C for 48 h to obtain a stent 20 with a skirt coated on it; After two impregnation processes, a uniform polyurethane film is formed on the surface of the stent 20. The film thickness on the stent 20 can reach about 50 μm, and the film thickness between the diamond-shaped grids of the stent 20 can reach about 100 μm, which can ensure that the skirt remains intact during the process of the valve entering the delivery device and being used in the human body;

[0066] S2. Bond the leaflet and the skirt together by means of thermal welding. Before welding, dry the leaflet at 100 °C for 6 h. The specific process is as follows: After sleeving the stent 20 wrapped with the skirt on the support member 10, lay the edge of the leaflet on the surface of the skirt, so that a part of the leaflet overlaps with the skirt, and align the leaflet according to the reference line 101 on the surface of the support member 10, so that the bonding areas of the leaflet and the skirt are aligned with each other. Then, place a soldering iron with a top width of 1 mm on the connection between the leaflet and the skirt, melt the polyurethane on the leaflet, and use the melted polyurethane to bond the leaflet and the skirt together. During the welding process, the temperature of the soldering iron is 180 °C, and the moving speed of the soldering iron is 10 mm / s. After welding, anneal in a constant temperature air blast drying oven at 85 °C for 4 h, and then the oven slowly cools down to room temperature. Take out the valve. The width of the bonding area between the leaflet and the skirt in the valve is 1000 μm.

[0067] The performances of the valves prepared in Examples 1 to 4 are shown in Table 1. The evaluation of the valve performances refers to the industry standard (YY / T 1449.3-2016 Transcatheter Implantable Heart Valve). It can be seen from the data in Table 1 that the fatigue times of the valves prepared in Examples 1 to 4 all exceed 400 million times, and none of them failed at the end of the test. The other performances can all meet the minimum performance requirements of the industry standard.

[0068] Table 1 Comparison of the performances of the valves prepared in Examples 1 to 4

[0069] Performance Example 1 Example 2 Example 3 Example 4 Number of fatigue times / 100 million times 4.1 4.1 4.0 4.1 <![CDATA[Effective orifice area / cm 2 > 3.1 2.9 3.1 3.0 Percentage of valvular regurgitation (accounting for forward flow) / % 7.5 4.6 6.0 9.2 Total percentage of regurgitation (accounting for forward flow) / % 9.6 9.0 11.7 16.1

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A molding method for a polymeric artificial heart valve, characterized in that, The method includes the following steps: Prepare a skirt on the stent; Place a part of the leaflet on the surface of at least a part of the skirt or dock the edge of the leaflet with at least a part of the skirt, where both the leaflet and the skirt are made of polymer materials; Bond the edges of the leaflet and the skirt together by means of interfacial micro-treatment, and after drying, obtain the polymer artificial heart valve; The interfacial micro-treatment is achieved by bonding the edges of the leaflet and the skirt with the aid of a second polymer solution or by thermal bonding between the leaflet and the skirt.

2. The forming method of the polymer artificial heart valve according to claim 1, characterized in that, The method for preparing a skirt on the stent includes the following steps: Immerse the stent in a first polymer solution with a mass percentage of 10 - 20%, then perform dip coating and pulling at a pulling speed of 1000 - 1200 mm / s, and dry at a temperature of 50 - 60 °C for 4 - 5 h. Then perform secondary dipping, and after drying at 50 - 60 °C for 48 - 60 h, the skirt is formed on the surface of the stent.

3. The molding method of the polymer artificial heart valve according to claim 1, characterized in that The method for bonding the leaflet and the skirt with the second polymer solution is one or more of solution dipping method, solution dispensing method, and solution spraying method; the method for thermal bonding is one or more of thermal welding method, laser welding method, and infrared welding method; the width of the bonding area between the leaflet and the skirt is 1000 - 1200 μm.

4. The molding method of the polymer artificial heart valve according to claim 1, characterized in that, The method for preparing a skirt on the stent includes directly forming a skirt integrally connected to the stent on the stent by dipping method or fixing a pre-made skirt on the stent.

5. The forming method of the polymer artificial heart valve according to claim 3, characterized in that, When using the solution dipping method or solution dispensing method to bond the leaflet and the skirt, the viscosity of the second polymer solution is 300 - 300000 cP, the solid content of the solution is 5 - 30%, and the pulling speed during the dipping process is 1 - 10000 μm / s; preferably, the viscosity is 5000 - 20000 cP, the solid content of the solution is 10 - 20%, and the pulling speed is 500 - 2000 μm / s.

6. The molding method of the polymeric artificial heart valve according to claim 3, characterized in that, When using the solution dispensing method, the dispensing pressure is 40 - 60 psi; when using the solution spraying method, the viscosity of the second polymer solution is 1 - 100 cP, the solid content of the solution is 1 - 20%, preferably, the viscosity of the second polymer solution is 5 - 50 cP, and the solid content of the solution is 3 - 8%.

7. The forming method of the polymeric artificial heart valve according to claim 1, characterized in that, The material of the skirt is one or more of polyethylene terephthalate, polyurethane, and polyolefin - polyethylene terephthalate blended fabric; the material of the leaflet is one or more of polyurethane and its fiber - reinforced materials, styrene - isobutylene - styrene copolymer and its cross - linked products, styrene - butadiene - styrene copolymer and its cross - linked products, silicone rubber, and polytetrafluoroethylene.

8. The molding method of the polymer artificial heart valve according to claim 1, characterized in that, The process of bonding the leaflets and the skirt is carried out by means of a clamping die, which includes a support for supporting the stent; the support includes a cylindrical body with a smooth outer wall, one end of the cylindrical body is provided with a plurality of concave areas, and the shape enclosed by the outer walls of the plurality of concave areas is adapted to the shape of the natural leaflet in the open or closed state. A reference line is provided on the outer wall of the cylindrical body, and the reference line is used to provide a reference for the alignment of the stent and the support.

9. The molding method of the polymeric artificial heart valve according to claim 8, wherein, The clamping die further includes a fixing member sleeved outside the support; the fixing member includes a base and a plurality of protrusions evenly arranged on the base. The base is a circular ring, and the protrusions protrude outward along the central axis direction of the base; the edge lines of all the protrusions away from the base together form a positioning line; when the fixing member is sleeved outside the support, the reference line and the positioning line coincide.

10. The molding method of the polymeric artificial heart valve according to claim 9, characterized in that, The material of the clamping die is a metal material, a rigid polymer material or a soft polymer material.

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