A vascular stent fabric coating with sparse and dense yarn distribution and a manufacturing method thereof

Abstract

The present invention relates to a vascular stent fabric covering with a sparsely distributed yarn pattern and a method for producing the same. The fabric comprises a double-warp plain weave with pre-set circular holes in the compact structural domain for docking branch vascular stents. The mesh structure exhibits high extensibility and elasticity, and its high porosity reduces the outer diameter of the delivery system. The double-warp plain weave effectively improves bending compliance while preventing tearing at the openings. The present invention utilizes a double-needle-bed warp knitting machine to produce the stent fabric covering with a sparsely distributed yarn pattern, effectively improving delivery performance while also ensuring the stent has good conformability and durability.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedicine, and in particular to a vascular stent fabric coating with sparse and dense yarn distribution and a manufacturing method thereof. Background Art

[0002] Aortic dissection and aortic aneurysm are common aortic diseases with high morbidity and mortality rates. Endovascular stent implantation is the most proactive and effective treatment for these diseases. Currently, the most commonly used vascular stents include bare metal stents and covered stents. However, bare metal stents cause significant damage to blood vessels, which can easily lead to restenosis or even occlusion within the stent. Covered stents, on the other hand, combine the characteristics and functions of metal stents and membrane materials. Covered stents are made of a metal stent and a membrane through composite processing or suture stitching. The membrane is often made of polyester, polypropylene, nylon, silk, and expanded polytetrafluoroethylene. It can effectively prevent intimal hyperplasia and reduce the restenosis rate of blood vessels. Therefore, covered stents have been more widely used in the treatment of aortic diseases.

[0003] The invention patent with application number 201610247886.9 has designed and developed a fabric covering that can improve the durability of the stent and fabric covering. The invention patent with application number 201710449717.8 has designed and developed a fabric covering with local reinforcement at the in-situ window. The improvement of the overall performance of the stent by the covered fabric in the above patents does not take into account the size of the delivery system and the compliance of the stent. Because the presence of the membrane material on the outer surface of the stent will increase the grip volume, the size of its delivery system will be much larger than that of the bare stent delivery system. In addition, the coated stent system has poor flexibility and will have certain difficulties in passing through curved blood vessels. Summary of the Invention

[0004] The present invention aims to provide a fabric covering for vascular stents used in endovascular repair procedures for aortic diseases. This coating leverages the advantages of a dense and coarse yarn structure to reduce the overall compression and gripping volume of the stent during delivery. The excellent transverse and longitudinal ductility of the double-warp plain weave improves stent durability and conformability. Furthermore, the reduced thickness of the mesh structure when compressed by external forces reduces the compression and gripping volume, thereby improving delivery performance.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] On the one hand, the present invention provides a vascular stent fabric covering with a sparse and dense distribution of yarns, comprising a loose structural domain and a tight structural domain, wherein the loose structural domain and the tight structural domain are woven into a circular tubular structure; a circular hole is provided on the tight structural domain, and a circular hole is formed at one end of the tight structural domain by a weaving method in which the front and rear needle beds are not connected to form a loop, and the diameter of the circular hole is positively correlated with the number of unconnected horizontal rows woven front and back.

[0007] In the above-mentioned vascular stent fabric covering, the fabric tissue of the tight structural domain is a double warp plain tissue, and is woven in the form of a warp plain right-open coil; the fabric tissue of the loose structural domain is a mesh tissue.

[0008] In the above-mentioned vascular stent fabric coating, the area ratio of the tight structure domain and the loose structure domain is 1:4-1:10.

[0009] In the above-mentioned vascular stent fabric covering, the fabric covering is woven from at least one material selected from the group consisting of polyester, polypropylene, nylon and silk.

[0010] In the above-mentioned vascular stent fabric covering, the tight structure domain is a rectangle with a total weaving width of 5-30 mm, and the number of weaving is 1-10 pieces; the loose structure domain is a rectangle with a total weaving width of 20-120 mm, and the number of weaving is 1-10 pieces;

[0011] In the above-mentioned vascular stent fabric covering, the vascular stent fabric covering has a length of 40-300 mm, an outer diameter of 8-48 mm, and a wall thickness of 0.05-0.3 mm;

[0012] In the above-mentioned vascular stent fabric covering, the diameter of the circular holes is 6-14 mm, and the number of the circular holes is 1-3.

[0013] On the other hand, the present invention also provides a method for preparing a vascular stent fabric covering with a sparse and dense yarn distribution. The method for preparing any of the above vascular stent fabric coverings comprises the following steps:

[0014] The first step is to determine the weaving structural parameters, including the weaving length and diameter of the vascular stent fabric covering, the proportion of loose structural domains, the proportion of tight structural domains, and the diameter of the circular holes;

[0015] In the second step, a double-needle-bed warp knitting machine is used to weave loose structural domains, tight structural domains and circular holes;

[0016] The third step is to cover the woven vascular stent fabric membrane on a stainless steel rod of selected size and heat-treat it at 90-150°C for 5-35 minutes;

[0017] The fourth step is to clean and dry the heat-treated vascular stent fabric covering to finally obtain a vascular stent fabric covering with a sparse or dense distribution.

[0018] The beneficial effects of the present invention are:

[0019] The mesh fabric is composed of numerous small, mesh-shaped holes, offering significant extensibility and elasticity. Due to its high porosity, when the fabric is bent and compressed by external forces, the load-bearing points are the yarn contact points, resulting in a smaller thickness and space occupied by the fabric, thereby reducing the outer diameter of the conveyor system. The double-warp plain weave coils are closely arranged in an inclined position, resulting in excellent ductility both horizontally and vertically. The double-warp plain weave also facilitates stitching to the stent as a needle point, effectively improving bending compliance while preventing tearing at the openings. The present invention utilizes a double-needle-bar warp knitting machine to produce a stent fabric coating with a sparsely distributed yarn pattern, effectively improving conveying performance while also ensuring the stent's excellent conformability and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structural principle of the present invention;

[0021] Figure 2 This is a schematic diagram of the loose structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the compact structure of the present invention;

[0023] In the picture:

[0024] 1-loose domain; 2-tight domain; 3-circular pore. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. It should be understood that the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. In addition, after reading the contents of the present invention, ordinary technicians in this field can make improvements without departing from the creative concept of the present invention, but these improvements are all within the scope of protection of the present invention.

[0026] refer to Figures 1 to 3 The present invention comprises a loose structural domain (1) and a tight structural domain (2), wherein the loose structural domain (1) and the tight structural domain (2) are woven to form a circular tubular structure; a circular hole (3) is provided on the tight structural domain (2), and a circular hole (3) is formed at one end of the tight structural domain (2) by a weaving method in which the front and rear needle beds are not connected to form a loop, and the diameter of the circular hole (3) is positively correlated with the number of unconnected horizontal rows woven therein.

[0027] In this embodiment, the fabric structure of the tight structure domain (2) is a double warp plain weave, and is woven in the form of a warp plain right open coil; the fabric structure of the loose structure domain (1) is a mesh weave. Of course, other similar weaves can also be used to achieve the same effect.

[0028] The area ratio of the tight structure domain (2) to the loose structure domain (1) is 1:4-1:10.

[0029] The invention is woven from at least one material selected from polyester, polypropylene, nylon and silk.

[0030] The tight structure domain (2) is a rectangle with a total weaving width of 5-30 mm and a weaving quantity of 1-10 pieces; the loose structure domain (1) is a rectangle with a total weaving width of 20-120 mm and a weaving quantity of 1-10 pieces.

[0031] The length of the present invention is 40-300 mm, the outer diameter is 8-48 mm, and the wall thickness is 0.05-0.3 mm. The diameter of the circular hole (3) is 6-14 mm, and the number of the circular holes (3) is 1-3. When a plurality of circular holes (3) are preset, the diameter of each circular hole (3) can be the same or different, the center of each circular hole (3) can be located on the same axis, or can be preset in a staggered manner, the distance between the centers of different circular holes (3) along the axial direction is 6-54 mm, and the straight-line distance between the axial lines where the centers of different circular holes (3) are located along the circumferential direction is 0-20 mm.

[0032] The preparation method of the present invention is described with reference to the following embodiments:

[0033] Example 1

[0034] like Figure 1 The figure shows a three-dimensional schematic diagram of a vascular stent fabric covering with a densely distributed yarn woven by a double needle bed warp knitting machine, comprising: a mesh structure (1) and a double warp plain structure (2) with circular holes (3) pre-set thereon. The yarn is polyester multifilament.

[0035] The first step was to determine the structural parameters of the fabric coating to reduce its overall compression volume. The circular tubular fabric had a weaving length of 200 mm and a diameter of 32 mm. The loose structure was a mesh weave, accounting for 80%, while the tight structure was a double warp plain weave, accounting for 20%, with a circular hole diameter of 10 mm.

[0036] In the second step, the tubular fabric covering is weaved on a double needle bed warp knitting machine.

[0037] In the third step, after weaving is completed, the fabric coating is put on a stainless steel rod and heat-treated at 125°C for 10 minutes. After air cooling, it is removed for cleaning and drying, and finally a vascular stent fabric coating with a sparse and dense yarn structure is obtained.

[0038] The thickness of the obtained fabric coated mesh structure with a sparse and dense yarn structure distribution is 0.13 mm, and the thickness of the double warp plain structure is 0.18 mm.

[0039] Example 2

[0040] like Figure 1The figure shows a three-dimensional schematic diagram of a vascular stent fabric covering with a densely distributed yarn woven by a double needle bed warp knitting machine, comprising: a mesh structure (1) and a double warp plain structure (2) with circular holes (3) pre-set thereon. The yarn is polyester multifilament.

[0041] The first step was to determine the structural parameters of the fabric coating. The circular tubular fabric had a weaving length of 250 mm and a diameter of 38 mm. The loose structural domain was a mesh weave, accounting for 90%, while the tight structural domain was a double warp plain weave, accounting for 10%, with a circular hole diameter of 8 mm.

[0042] In the second step, the tubular fabric covering is weaved on a double needle bed warp knitting machine.

[0043] In the third step, after weaving is completed, the fabric coating is put on a stainless steel rod and heat-treated at 110°C for 15 minutes. After air cooling, it is removed for cleaning and drying, and finally a vascular stent fabric coating with a sparse and dense yarn structure is obtained.

[0044] The thickness of the obtained fabric coated mesh structure with a sparse and dense yarn structure distribution is 0.10 mm, and the thickness of the double warp plain structure is 0.16 mm.

[0045] It can be seen from the above embodiments that the technical solution of the present invention has the following advantages:

[0046] (1) The fabric coating with sparse and dense yarn distribution prepared by the present invention can control the flexibility of the fabric and the thickness after pressing and gripping by adjusting the weaving process parameters of different tissues, so as to reduce the outer diameter of the delivery sheath tube, thereby obtaining a fabric coating with ideal performance.

[0047] (2) The fabric membrane with sparse and dense yarn distribution prepared by the present invention adopts a mesh structure with a large number of pores in the loose structural domain, and its typical porous structure is conducive to cell attachment and growth.

[0048] (3) The fabric coating prepared by the present invention has a sparse and dense yarn distribution, and the tight structural domain is woven with a double warp plain weave with tightly arranged coils, which is easy to sew as a needle point and can improve the suturing strength of the stent.

[0049] In summary, the present invention adopts a circular tubular fabric with a densely distributed polyester yarn weaving structure as a vascular stent fabric coating. Among them, the mesh tissue, as a loose structural domain, accounts for a relatively high proportion. Because of its high porosity, the volume after compression is small, and it will not increase the overall compression and gripping volume of the stent too much, which can reduce the outer diameter of the delivery system and improve the delivery performance. The double-warp plain tissue uses less material, has clear lines and good ductility in both the horizontal and vertical directions. It is also easy to suture with a needle as a tight structure, which can strengthen the overall strength of the circular tubular fabric coating, and the opening position is set at the double-warp plain tissue structure, which can improve the compliance of the stent and effectively prevent the opening from tearing during surgical treatment, thereby improving the durability of use.

[0050] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A vascular stent fabric coating with sparse and dense yarn distribution, characterized in that: The invention comprises a loose structural domain (1) and a tight structural domain (2), wherein the loose structural domain (1) and the tight structural domain (2) are woven to form a circular tubular structure; a circular hole (3) is provided on the tight structural domain (2), and a circular hole (3) is formed at one end of the tight structural domain (2) by weaving in a manner in which the front and rear needle beds are not connected to form a loop, and the diameter of the circular hole (3) is positively correlated with the number of unconnected horizontal rows woven in the front and rear; the fabric structure of the tight structural domain (2) is a double warp plain structure, and is woven in the form of a warp plain right-open coil; the fabric structure of the loose structural domain (1) is a mesh structure.

2. The vascular stent fabric coating with yarn density distribution according to claim 1, characterized in that: The area ratio of the tight structure domain (2) to the loose structure domain (1) is 1:4-1:

10.

3. The vascular stent fabric coating with a yarn density structure distribution according to claim 1, characterized in that: The vascular stent fabric covering is woven from at least one material selected from the group consisting of polyester, polypropylene, nylon and silk.

4. The vascular stent fabric coating with yarn density distribution according to claim 1, characterized in that: The tight structure domain (2) is a rectangle with a total weaving width of 5-30 mm, and the number of weaving is 1-10 pieces; the loose structure domain (1) is a rectangle with a total weaving width of 20-120 mm, and the number of weaving is 1-10 pieces.

5. The vascular stent fabric coating with yarn density distribution according to claim 1, characterized in that: The length of the vascular stent fabric coating is 40-300 mm, the outer diameter is 8-48 mm, and the wall thickness is 0.05-0.3 mm.

6. The vascular stent fabric coating with yarn density distribution according to claim 1, characterized in that: The diameter of the circular holes (3) is 6-14 mm, and the number of the circular holes (3) is 1-3.

7. A method for preparing a vascular stent fabric coating with sparse and dense yarn distribution, characterized in that: A method for preparing a vascular stent fabric covering according to any one of claims 1 to 6, comprising the following steps: The first step is to determine the weaving structural parameters, including the weaving length and diameter of the vascular stent fabric covering, the proportion of loose structural domains, the proportion of tight structural domains, and the diameter of the circular holes; In the second step, a double-needle bed warp knitting machine is used to weave the loose structure domain (1), the tight structure domain (2) and the round hole (3); The third step is to cover the woven vascular stent fabric membrane on a stainless steel rod of selected size and heat-treat it at 90-150°C for 5-35 minutes; The fourth step is to clean and dry the heat-treated vascular stent fabric covering to finally obtain a vascular stent fabric covering with a sparse or dense distribution.

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