Valve stent covering fabric, preparation method therefor and use thereof

Abstract

A valve stent covering fabric, which is used for being fitted over a valve stent body (5). The valve stent covering fabric comprises an integrally formed tubular braid (6) which is elastic and deformable; the tubular braid (6) has a diameter smaller than the diameter of the valve stent body (5), and the tubular braid (6) has a length adapted to the total length of the valve stent body (5), so as to be suitable for covering the valve stent body (5). The valve stent covering fabric can be customized according to the actual size of the valve stent body (5), the valve stent covering fabric is fitted over the valve stent body (5) before the valve stent body (5) is welded, and after welding, fabric covering can be completed by only connecting and stitching the two ends of the valve stent covering fabric. According to the method, time is efficiently saved, and the inner diameter of the tubular braid (6) can be customized on the basis of the size of the valve stent body (5), thereby achieving tighter covering and preventing the occurrence of displacement.

Description

A kind of petal frame covering fabric and its preparation method and application Technical Field

[0001] The present invention relates to the field of artificial heart valves, and in particular to a valve frame covering fabric, a preparation method and an application thereof. Background Art

[0002] Surgical valves contain structures such as leaflets, a valve frame, a valve seat, and a sewing ring. The leaflets and the valve frame need to be connected together. Existing technologies, including the gold standard Edwards surgical mitral valve, use flat strips of fabric. The covering fabric is sewn onto the metal valve frame by folding and sewing. The leaflets and the covering fabric on the valve frame are then sutured to connect the leaflets and the valve frame. However, existing technologies have several disadvantages. First, the folding suturing takes a long time, requiring 2-3 hours. Second, manual folding and sewing can result in uneven covering tightness, resulting in uneven tension after the leaflets are connected. Third, the folding suturing generally cannot fit the covering fabric and the valve frame tightly, which makes it easy for the covering fabric to slip on the surface of the valve frame, causing the leaflets to slip, thereby causing the valve product to fail.

[0003] Summary of the Invention

[0004] The purpose of the present invention is to provide a valve frame covering fabric, which is an integrally formed valve frame covering tubular braid produced by weaving. The tubular braid can be put on the valve frame body to provide a tighter and more fitting covering, thereby preventing the displacement of the leaflet caused by the displacement of the covering cloth during the suturing of the leaflet.

[0005] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0006] The present invention provides a valve frame covering fabric for being sleeved on a valve frame body. The valve frame covering fabric includes an integrally formed, elastically deformable tubular braid; the diameter of the tubular braid is smaller than the diameter of the valve frame body, and the length of the tubular braid is adapted to the total length of the valve frame body so as to be suitable for covering the valve frame body.

[0007] As a preferred embodiment, the braiding wire of the tubular braid is PET, PE, PTFE or DYT yarn; the braiding weft density of the tubular braid is 50-150 wefts / inch.

[0008] As a preferred embodiment, the braiding length of the tubular braid is 1-2 mm longer than the circumference of the valve frame body.

[0009] As a preferred embodiment, the inner diameter of the tubular braid is 0-0.1 mm smaller than the diameter of the valve frame body.

[0010] The present invention also provides a method for preparing a valve frame covering fabric, comprising the following steps:

[0011] S1, before weaving begins, inserting a metal wire into the center of a weaving hole of a weaving machine, and weaving yarn around the metal wire, wherein the diameter of the metal wire is 0.1-0 mm smaller than the diameter of the valve frame body;

[0012] S2, after weaving begins, the pulling speed of the braiding machine is 10-100 mm / min; the yarn is braided around the metal wire to form an elastic tubular braid;

[0013] S3. After weaving is completed, the two ends of the fabric are cut off and removed from the metal wire to obtain an elastic tubular braid. The two ends of the fabric include the weaving start end and the weaving end end. There will be a knot at the starting end, which is usually cut off; it is also possible not to cut it. If the starting end is not cut off, only the weaving end end of the fabric is cut at this time.

[0014] As a preferred embodiment, the braiding machine is a 6-12 spindle braiding machine; the step pulling speed is 10-50 mm / min; the yarn is selected from PET, PE, PTFE or DYT yarn; the braiding weft density of the tubular braid is 50-150 wefts / inch.

[0015] As a preferred embodiment, the cutting in step S3 is performed by laser cutting, so that the cut edge of the fabric produces a fused edge to prevent the yarn from falling apart, and the cutting length is 1-2 mm longer than the circumference of the valve frame body.

[0016] The present invention also provides an application of the valve frame covering fabric in the field of artificial heart valves.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a valve frame covering fabric, which is a one-piece tubular braid produced through a weaving process. This fabric can be customized to the actual dimensions of the valve frame. Before welding the valve frame, the covering fabric is placed over the frame. After welding, the fabric covering is completed by simply butting and sewing the two ends of the fabric together. This method is highly efficient and time-saving, and the inner diameter of the tubular braid can be customized to the dimensions of the valve frame, enhancing the fit between the covering fabric and the frame, and preventing slippage during suturing of the valve leaflets. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram of metal wire passing through a braiding point in a braiding method of a braiding machine according to the present invention.

[0020] FIG2 is an enlarged schematic diagram of a metal wire passing through a braiding point in the braiding method of the braiding machine of the present invention.

[0021] FIG3 is a schematic diagram of the cut tubular braid of the present invention being sheathed on a metal valve frame body that has not yet been welded.

[0022] FIG4 is an enlarged schematic diagram of the cut tubular braid of the present invention being sleeved on the metal valve frame body that has not yet been welded.

[0023] FIG5 is a schematic diagram of the metal valve frame body covered with a tubular braid after welding according to the present invention.

[0024] FIG6 is a schematic diagram of mattress-type suture of the mate points of the stacked portion of the tubular braid after welding the metal valve frame body of the present invention.

[0025] The meanings of the symbols in the figure are as follows: 1. 6-spindle braiding machine, 2. Metal wire, 3. Center of braiding hole, 4. Yarn, 5. Metal flap body, 6. Tubular braid, 7. Flange end, 8. Fabric end, 9. Tubular braid joint point, 10. Suture line. DETAILED DESCRIPTION

[0026] The present invention provides a tubular fabric, manufactured by a weaving method. The integrally formed tubular fabric can be customized according to the actual size of the valve frame body. Generally, different manufacturers use different valve frame body diameters. For example, Manufacturer A uses a valve frame body with a diameter of 0.5 mm, while Manufacturer B uses a valve frame body with a diameter of 0.6 mm. When making the covering fabric, simply weaving with metal wire of a slightly smaller diameter can meet the customization requirements of different manufacturers. The braided tubular fabric has a certain degree of elasticity, allowing it to be stretched to a certain extent when it is put on, and then tightened when the fabric is finally butted and sewn.

[0027] The valve is composed of structures such as leaflets, a valve frame, a valve seat, and a suture ring. The leaflets and the valve frame need to be connected together, but the existing practice is to sew the covering cloth on the valve frame, and then sew the leaflets to the covering cloth. However, the applicant has found that this practice is prone to the problems mentioned in the background technology. This practice not only makes the installation process of the leaflets complicated, but also causes the tightness of the covering cloth to be wrapped, resulting in a gap between the covering cloth and the valve frame, and the covering cloth and the valve frame do not fit well. What's more, a normal person opens and closes the valve 108,000 times a day. After the leaflets of the heart valve are implanted in the body, they need to continue to open and close. The leaflets are always in motion to ensure that the blood can continue to flow. At the same time, during the blood flow, under the flushing of the blood, if the covering cloth is not tight, it will cause the covering cloth to shift. The covering can easily shift on the valve frame. The leaflets and the covering are sewn together, so shifting the covering can cause the leaflets to shift as well. This can affect the opening and closing of the leaflets, leading to incomplete regurgitation, increased regurgitation, and an inability to fully activate the valve. Severe shifting can even cause complete valve failure, which can be life-threatening. Furthermore, the product's durability is relatively poor.

[0028] Compared with the existing covering cloth method, the tubular woven covering fabric is not complicated in the operation process when connecting the covering fabric to the valve frame. It does not need to be folded and sewed, nor does it need to consider the tightness between the covering fabric and the valve frame during the suturing process. It can be directly put on the valve frame. Moreover, since the diameter of the covering fabric itself is smaller than the diameter of the valve frame and the covering fabric is elastic, the covering fabric and the valve frame fit more tightly, and it is not easy to cause the covering fabric to slip on the valve frame.

[0029] The braiding method of the present invention can be used with a 6-spindle, 8-spindle, or 12-spindle braiding machine, and is braided using yarns such as PET, PE, and PTFE. If PET yarn is used, DTY high-elastic yarn can be selected to increase the elasticity of the tubular fabric. Before braiding begins, a metal wire with a diameter slightly smaller than the diameter of the valve frame body (metal wire diameter = valve frame body diameter - 0.1 to 0 mm) is inserted. The metal wire used during braiding is not limited to cobalt-chromium wire. Since the maximum specification of a single valve frame body requires a braid of approximately 15 cm, a metal wire greater than 20 cm can ensure that at least one section can be cut out for use. The longer the metal wire, the more sections of the braided tubular fabric can be cut out to cover multiple valve frame bodies. The metal wire is inserted from the center of the braiding hole, and then braiding begins. After braiding begins, the yarn is woven onto the metal wire to form a tubular braid because the metal wire is at the braiding center. By pulling the metal wire at a constant speed, a tubular braid can be continuously formed on the wire. The pulling speed is 10-100 mm / min. Different pulling speeds can produce braids of different densities. The preferred pulling speed is 10-30 mm / min, and the weft density of the braid is 50-150 picks / inch. However, during the braiding process, if the pulling speed is too fast, the density of the tubular braid will be low. Low density will result in poor elasticity of the tubular braid, which will affect the tightness of the fit between the braid and the flap frame, affecting the suture strength of the fabric. If the pulling speed is too slow, the fabric density will be too high, resulting in low elasticity of the fabric, affecting the tightness of the fit between the braid and the flap frame, and low production efficiency.

[0030] After weaving, cut off both ends of the fabric. The single weaving length can be greater than 15 cm, and remove it from the metal wire. Use a laser cutting machine to cut the removed tubular braid. Laser cutting can produce a molten edge on the cutting edge of the tubular braid to prevent the yarn from falling apart.

[0031] The length of the tubular braid = the circumference of the valve frame body + 1 to 2 mm. The length of the tubular braid determines whether the fabric can be tightened during suturing. When the tubular braid is stretched, its diameter will be reduced. Therefore, an extra distance of 1 to 2 mm is reserved to ensure that the fabric is easy to sew while allowing the tubular braid to be tightened without slipping, thereby enhancing the fit between the covered tubular braid and the valve frame body and preventing slippage when suturing the leaflets.

[0032] Put the cut tubular braid on the metal petal frame body that has not been welded yet, and stack a part of it on both sides of the welding point. The end of the tubular braid slides more than 5mm away from the welding point to prevent damage to the fabric during welding. Then weld the metal petal frame body together, put the stacked part of the fabric over the welding point, tighten and smooth the tubular braid on the petal frame body, and sew the fabric ends of the tubular braid at both ends; the suturing position is the matching point. When cutting, the tubular braid is reserved 1-2mm more, that is, it is 1-2mm longer than the metal petal frame body. The overlapping part of the stitching is 2-3mm in length. Due to the elasticity of the fabric, it will be stretched a little to ensure a tighter fit. The distance between the suture point and the end of the tubular braid is 1-1.5mm. They are connected together using inner-to-inner mattress sutures. The main function is that after the suture is completed, the suture line uses yarn or suture of the same material as the braid, with specifications of 6-0, 5-0, and 4-0. The suture line and the fabric end will be hidden between the tubular braid and the valve frame body to avoid the tubular braid from being detached during actual use and to prevent thrombus formation at the edge of the valve frame, thereby achieving the purpose of prolonging human life.

[0033] The present invention also provides a valve frame, comprising a valve frame body and a valve frame covering fabric. The two ends of the valve frame body, when not welded, each have a valve frame port. In a specific implementation, the valve frame body is formed from nickel-titanium wire and can be used to mount three sets of single leaflets, as shown in FIG5 . After the valve frame body is welded, the two ends of the covering fabric are sewn together to cover the valve frame body. The welding method can be categorized as direct welding, sleeve laser welding, or sleeve riveting. Direct welding requires polishing, while sleeve laser welding and sleeve riveting do not. The two ends of the covering fabric are nested together, partially overlapping, and then sewn securely.

[0034] Compared with the one-piece suturing of the present invention, there is an obvious difference between the folded suturing and the one-piece suturing of the present invention when the valve frame covering cloth is just sewed; after the one-piece suturing is completed, the covering cloth is difficult to move by hand on the valve frame; while the folded suturing can easily move the covering cloth relatively on the valve frame by hand. Secondly, in addition to the leaflets needing to be sutured on the valve frame covering cloth, when the valve seat and the valve frame are connected, they will also be sutured with the valve frame covering cloth, which will cause slippage, resulting in inconsistent leaflet heights and other situations; slippage is mainly generated during the suturing process. As for the consequences caused by the above slippage, the covering fabric will be subjected to very little force after all suturing is completed.

[0035] The technical solution of the present invention is described in detail below with reference to the examples. Unless otherwise specified, the reagents and biological materials used below are all commercial products.

[0036] Example 1:

[0037] Prepare PET 20D DTY yarn, as shown in Figures 1-2. Figure 1 is a schematic diagram of the metal wire passing through the braiding point in the braiding machine braiding method of the present invention, and Figure 2 is an enlarged schematic diagram of the metal wire passing through the braiding point. Yarn 4 is braided on a 6-spindle braiding machine 1. Before braiding, a metal wire 2 with a diameter of 0.6 mm, which is a cobalt-chromium wire with a length greater than 55 cm, is passed through the center of the braiding hole 3. The length of the braid passing through the center of the braiding hole is 50 cm. The braided fabric has a weft density of 50 picks / inch and a braiding speed of 20 mm / min. Braiding continues until the lowest end of the cobalt-chromium wire passes through the center of the braiding hole. Stop the braiding and cut the yarn connecting the two ends of the metal wire. The tubular braid, approximately 50 cm in length, can be removed from the metal wire.

[0038] The metal valve frame body 5 is made of nickel-titanium, with a diameter of 0.65 mm and a circumference of 8 cm. A laser cutter is used to cut the tubular braid 6 perpendicular to the circumference of the wire into 8.2 mm sections, as shown in Figures 3-4. Figure 3 shows the cut tubular braid being placed over the unwelded metal valve frame body, while Figure 4 is an enlarged view. The tubular braid 6 is placed over the unwelded nickel-titanium valve frame body from the valve frame body port 7. The fabric port 8 is slid approximately 5 mm away from the welding point to prevent damage to the fabric during welding. The two ports of the metal valve frame are then welded together. As shown in Figure 5, a schematic diagram of the metal valve frame body covered with a tubular braid after welding is shown. Compared to Figure 3, the black material attached to the surface of the valve frame body represents the tubular braid. The stacked portion of the fabric is welded, and the tubular braid on the valve frame body is tightened and smoothed. As shown in Figure 6, the joint points 9 of the tubular braid are connected together using an inside-to-inside mattress suture. The suture thread uses a yarn or suture of the same material as the braid, with a specification of 6-0. The overlap width of the suture is within a range of 2-3 mm. Below this range, the covering is not tight enough. Exceeding this range, the fabric cannot be stretched to such a long length. The metal wire used during the braiding process is slightly smaller, and the reserved 1-2 mm of suture length will be consumed during the suture process. Further extension will make it impossible to pull. Therefore, exceeding this range, the suture cannot be connected. After the suturing is completed, the suture thread 10 and the fabric port 8 will be hidden between the tubular braid and the valve frame body, and will not cause other impacts. The one-piece valve frame covering fabric is tightly wrapped after the port is sutured. When the valve frame, valve seat and suture ring are subsequently sutured and connected, the covering fabric will not be shifted due to the suturing, thereby avoiding the unevenness and wrinkles of the leaflets caused by the displacement of the covering fabric.

[0039] Example 2:

[0040] Prepare PEFE 100D yarn and braid yarn 4 on a 12-spindle braiding machine, referring to Example 1. Before braiding, pass a metal wire 2 with a diameter of 0.6 mm. A cobalt-chromium wire with a length greater than 55 cm is used. The wire passes through the braiding point 3 and the length passing through the center of the braiding hole is 50 cm. The braid has a weft density of 150 picks / inch and a braiding speed of 13 mm / min. Braiding is continued until the lowest end of the cobalt-chromium wire passes through the center of the braiding hole. Stop the braiding and cut the yarn connecting the two ends of the wire. The tubular braid, approximately 50 cm in length, can be removed from the metal wire 2.

[0041] The metal valve frame body is made of nickel-titanium, with a diameter of 0.65 mm and a circumference of 5 cm. A 5.2 mm section is cut from the tubular braid using a laser cutter, as shown in Figures 3-4. The tubular braid is then placed over the unwelded nickel-titanium valve frame body from the valve frame end. The fabric end is slid approximately 5 mm away from the weld point to prevent damage to the fabric during welding. Then, as shown in Figure 5, the two ends of the metal valve frame are welded together. The stacked fabric portion is passed through the weld, and the tubular braid on the valve frame body is tightened and smoothed. As shown in Figure 6, the matching points of the tubular braid are connected using an inside-to-inside horizontal mattress suture. The suture thread uses a 4-0 yarn or suture of the same material as the braid, with an overlap width of 2 to 3 mm. If the length falls below this range, the wrapping will be insufficient. Exceeding this range means the fabric cannot be stretched to this length. The braided wire is already slightly smaller, and the 1-2mm of suture length reserved is consumed during the stitching process. Further stretching will prevent the suture from being held together. Therefore, if the length falls outside this range, the suture thread and knot will be hidden between the tubular braid and the valve frame, without causing any other problems.

[0042] The above are only some preferred embodiments of the present invention, and the present invention is not limited to the contents of the embodiments. For those skilled in the art, various changes and modifications can be made within the scope of the technical solution of the present invention, and any changes and modifications made are within the scope of protection of the present invention.

Claims

1. A valve frame covering fabric, used for sleeved on a valve frame body, characterized in that: The valve frame covering fabric includes an integrally formed and elastically deformable tubular braid; the diameter of the tubular braid is smaller than the diameter of the valve frame body, and the length of the tubular braid is adapted to the total length of the valve frame body so as to be suitable for covering the valve frame body.

2. The flap covering fabric according to claim 1, characterized in that: The braiding wire of the tubular braid is PET, PE, PTFE or DYT yarn; the braiding weft density of the tubular braid is 50-150 wefts / inch.

3. The flap covering fabric according to claim 1, characterized in that: The braiding length of the tubular braid is 1-2 mm longer than the circumference of the valve frame body.

4. The flap covering fabric according to claim 1, characterized in that: The inner diameter of the tubular braid is 0-0.1 mm smaller than the diameter of the valve frame body.

5. A method for preparing a flap frame covering fabric, characterized in that: The following steps are involved: S1, before weaving begins, insert a metal wire into the center of a weaving hole of a weaving machine, and then weave the metal wire with yarn, wherein the diameter of the metal wire is 0.1-0 mm smaller than the diameter of the valve frame body; S2, after weaving starts, the pulling speed of the braiding machine is 10-100 mm / min; the yarn is woven around the metal wire to form an elastic tubular braid; S3, after the weaving is completed, the two ends of the fabric are cut off and removed from the metal wire to obtain an elastic tubular braid.

6. The method according to claim 5, characterized in that The braiding machine is a 6-12 spindle braiding machine; The pulling speed is 10-50 mm / min; The yarn is selected from PET, PE, PTFE or DYT yarn.

7. The method according to claim 5, characterized in that The tubular braid has a weft density of 50-150 wefts / inch.

8. The method according to claim 5, characterized in that The cutting in step S3 is performed by laser cutting, so that the cut edges of the fabric are fused to prevent the yarn from falling apart.

9. The method according to claim 5, characterized in that The length of the cutting is 1-2 mm longer than the circumference of the valve frame body.

10. Use of the valve frame covering fabric according to claim 1 in the field of artificial heart valves.

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