Artificial blood vessels

Abstract

To provide an artificial blood vessel capable of improving blood leakage resistance while keeping flexibility.SOLUTION: An artificial blood vessel VE has a predetermined woven structure obtained by weaving warps 1 and wefts 2. At least one of the warps 1 and the wefts 2 are configured of multifilament yarns including a plurality of filament yarns. The artificial blood vessel VE comprises: a plurality of covering parts C which are provided at a plurality of places on the surface of the artificial blood vessel VE and respectively cover therewith the multifilament yarns in a planar state; and uncovered parts UC which are provided between the plurality of covering parts C on the surface of the artificial blood vessel VE and are not covered with the covering parts C.SELECTED DRAWING: Figure 5

Description

Technical Field

[0004] , ,

[0006] , , , , , ,

[0005] , , ,

[0003] , , , , , ,

[0001] The present invention relates to an artificial blood vessel.

Background Art

[0002] Artificial blood vessels are used, for example, to replace diseased biological blood vessels. As shown in Patent Document for example, artificial blood vessels are composed of a woven structure of warp and weft threads. Artificial blood vessels are required to have little leakage of blood from the artificial blood vessel, that is, high leak resistance. The leak resistance of artificial blood vessels can be improved by increasing the weaving density of the warp and weft threads.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the weaving density of an artificial blood vessel is increased, although the leak resistance can be improved, the flexibility required for the artificial blood vessel is impaired.

[0005] Therefore, an object of the present invention is to provide an artificial blood vessel capable of improving leak resistance while maintaining flexibility.

Means for Solving the Problems

[0006] The artificial blood vessel of the present invention is an artificial blood vessel having a predetermined woven structure in which warp threads and weft threads are woven, wherein at least one of the warp threads and weft threads is composed of a multifilament thread containing a plurality of filament threads, and the artificial blood vessel has a plurality of covering portions provided at a plurality of locations on the surface of the artificial blood vessel, each covering the multifilament thread in a planar manner, and an uncovered portion provided between the plurality of covering portions on the surface of the artificial blood vessel and not covered by the covering portions. [Effects of the Invention]

[0007] According to the artificial blood vessel of the present invention, it is possible to improve blood leakage resistance while maintaining flexibility. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view of an artificial blood vessel of Embodiment 1. [Figure 2] This is a magnified view of area II in Figure 1. [Figure 3] Figure 1 is a fabric structure diagram showing an example of the woven structure of a base material used in artificial blood vessels. [Figure 4] Figure 3 is a schematic diagram of a cross-section of the substrate obtained by cutting along the line IV-IV. [Figure 5] Figure 3 is a schematic diagram of a cross-section of the substrate obtained by cutting along the VV line. [Figure 6] This is a SEM image of the surface of an artificial blood vessel. [Modes for carrying out the invention]

[0009] The following description of an artificial blood vessel according to one embodiment of the present invention will be given with reference to the drawings. Note that the embodiments shown below are merely examples, and the artificial blood vessel of the present invention is not limited to these embodiments.

[0010] In this specification, "perpendicular to A" and similar expressions shall not refer only to directions that are perfectly perpendicular to A, but shall also include directions that are approximately perpendicular to A. Furthermore, in this specification, "parallel to B" and similar expressions shall not refer only to directions that are perfectly parallel to B, but shall also include directions that are approximately parallel to B. Furthermore, in this specification, "C-shape" and similar expressions shall not refer only to perfect C-shapes, but shall also include shapes that visually resemble a C-shape (approximate C-shapes).

[0011] Figure 1 is a side view of an artificial blood vessel according to one embodiment of the present invention. Figure 2 is a magnified view of region II of the artificial blood vessel in Figure 1. Figure 3 is a fabric structure diagram showing an example of the woven structure of the base material used in the artificial blood vessel in Figure 1.

[0012] Artificial blood vessels are used, for example, to replace diseased biological blood vessels and to bypass them. As shown in Figures 1 and 2, the artificial blood vessel VE of this embodiment has alternating peaks M and valleys V formed in the direction of the axis X (see Figure 1) of the artificial blood vessel VE. When peaks M and valleys V are formed alternately in the artificial blood vessel VE, a flexible artificial blood vessel can be made, and it is less likely to kink when the artificial blood vessel VE is bent. In this embodiment, the artificial blood vessel VE is formed in a cylindrical shape with peaks M and valleys V formed in a spiral, but the artificial blood vessel does not have to have peaks M and valleys V.

[0013] The diameter of the artificial blood vessel VE can be changed depending on the site of use and is not particularly limited. For example, the artificial blood vessel VE may be a large-diameter artificial blood vessel with an inner diameter of 10 mm or more (for thoracoabdominal aorta), a medium-diameter artificial blood vessel with an inner diameter of 6 mm or more but less than 10 mm (for arteries in the lower limbs, neck, and axillary regions), or a small-diameter artificial blood vessel with an inner diameter of less than 6 mm. The thickness of the artificial blood vessel VE can be appropriately changed depending on the inner diameter and length of the artificial blood vessel used and is not particularly limited. For example, the thickness of the artificial blood vessel VE can be 0.1 to 2 mm.

[0014] The length of the vascular artery (VE) in the axial X direction can be changed depending on the site of use and is not particularly limited. For example, the length of the vascular artery in the axial X direction can be 100 to 1000 mm. The vascular artery is cut to a predetermined length by a physician or other medical professional when it is implanted in the desired site. Depending on the site of implantation, the vascular artery may be cut perpendicular to the axial X direction, or it may be cut at a predetermined angle to the axial X direction.

[0015] When an artificial blood vessel VE has peaks M and valleys V, the number of peaks M (or valleys V) (number of pleats) of the artificial blood vessel VE is not particularly limited, but can be set appropriately according to the required kink performance. For example, in the case of an artificial blood vessel with an outer diameter of 15 mm, the number of peaks M (number of pleats) of the artificial blood vessel VE can be 20 to 70, preferably 25 to 35, per 100 mm of length in the axial X direction. The spacing (pitch) in the axial X direction between the top Mt of a peak M (see Figure 2) and the top Mt of an adjacent peak M is not particularly limited, but can be, for example, 10 to 30%, preferably 15 to 25%, of the outer diameter of the artificial blood vessel VE (outer diameter at the top Mt of the peak M). The depth from the top Mt of a peak M to the bottom Vb of a valley V (see Figure 2) is not particularly limited, but can be, for example, 5 to 20%, preferably 5 to 15%, of the outer diameter of the artificial blood vessel VE.

[0016] In addition, in the present embodiment, the curvature at the top Mt of the mountain portion M is smaller than the curvature at the bottom Vb of the valley portion V (in the present embodiment, the radius of curvature at the top Mt of the mountain portion M is larger than the radius of curvature at the bottom Vb of the valley portion V). Note that "the curvature at the top Mt of the mountain portion M is smaller than the curvature at the bottom Vb of the valley portion V" means that the degree of curvature along the X-axis direction at the top Mt of the mountain portion M is smaller than the degree of curvature along the X-axis direction at the bottom Vb of the valley portion V (the curve of the mountain portion M is gentler than the curve of the valley portion V), and the mountain portion M and the valley portion V do not necessarily form a complete arc surface. When the curvature at the top Mt of the mountain portion M is smaller than the curvature at the bottom Vb of the valley portion V, when an external force is applied to the artificial blood vessel VE, stress concentrates on the valley portion V, so that the artificial blood vessel VE is likely to bend starting from the valley portion V. The curvatures of the mountain portion M and the valley portion V are not particularly limited. For example, the radius of curvature at the top Mt of the mountain portion M can be 5 to 8% of the diameter of the artificial blood vessel VE (and larger than the radius of curvature at the bottom Vb of the valley portion V). Also, the radius of curvature at the bottom Vb of the valley portion V can be 2 to 3% of the diameter of the artificial blood vessel VE (and smaller than the radius of curvature at the top Mt of the mountain portion M). Since the artificial blood vessel VE is more likely to bend, it becomes difficult for the bent artificial blood vessel VE to return to its original state, and the load on the connection site between the artificial blood vessel VE and blood vessels or the like can be reduced.

[0017] Note that the curved portion at the top Mt of the mountain portion M and the curved portion at the bottom Vb of the valley portion V can be connected by a flat portion PL (see FIG. 2). Thereby, compared with the case where the curved portions are directly connected to each other, the flexibility and the kink resistance performance can be further improved. The angle θ formed by the flat portion PL1 on one side and the flat portion PL2 on the other side can be set to be 20° to 40°, preferably 30°, and the angle θ formed by the flat portion PL1 on one side and the flat portion PL2 on the other side can be appropriately set according to the diameter of the artificial blood vessel, the height of the mountain portion, the height of the valley portion, the pitch, and the like.

[0018] Next, the configuration of the base material constituting the artificial blood vessel VE will be described.

[0019] The artificial blood vessel VE of this embodiment has a predetermined woven structure in which warp threads 1 and weft threads 2 are woven. The predetermined woven structure of the artificial blood vessel VE can be a known woven structure that can be used for artificial blood vessels, or a structure that combines known woven structures. For example, the artificial blood vessel VE may have a plain weave structure, a twill weave structure, a satin weave structure, or a composite structure of these woven structures, either as a whole or in part. In this embodiment, at least one of the warp threads 1 and weft threads 2 constituting the artificial blood vessel VE is made of a multifilament yarn containing multiple filament yarns. Note that only one of the warp threads 1 and weft threads 2 may be made of a multifilament yarn, or both the warp threads 1 and weft threads 2 may be made of a multifilament yarn.

[0020] In this embodiment, as shown in Figure 3, the artificial blood vessel VE has warp threads 1a to 1l (hereinafter collectively referred to as warp thread 1) extending along the axial X direction (vertical direction in Figure 3) and weft threads 2a to 2l (hereinafter collectively referred to as weft thread 2) extending along the circumferential direction of the artificial blood vessel VE (horizontal direction in Figure 3). More specifically, as shown in Figure 3, the artificial blood vessel VE has a plurality of warp threads 1a to 1l and a plurality of weft threads 2a to 2l, and has a woven structure in which warp threads 1 and weft threads 2 are interwoven. In Figure 3, warp thread 1 extends in the vertical direction, and the direction of extension of warp thread 1 (axial X direction of the artificial blood vessel VE) is called D1. Also in Figure 3, weft thread 2 extends in the horizontal direction, and the direction of extension of weft thread 2 (circumferential direction of the artificial blood vessel VE) is called D2. In Figure 3, the areas shown in black (with dots) are the parts where warp thread 1 is exposed to the outer surface (surface) of the artificial blood vessel VE, and the areas shown in white are the parts where weft thread 2 is exposed to the outer surface of the artificial blood vessel VE. The loom used to manufacture the artificial blood vessel VE is not particularly limited.

[0021] As will be described below, in the present embodiment, the warp 1 has portions R21 and R31 that extend across a plurality of wefts 2 (see FIGS. 3 and 5). Specifically, as shown in FIG. 3, the warp 1 has portions R21 and R31 that extend across a plurality of wefts 2, and portions R1, R22, and R32 that extend across one weft 2. Note that the warp 1 does not necessarily have to have a portion that extends across a plurality of wefts 2. Further, when the warp 1 has a portion that extends across a plurality of wefts 2, the woven structure of the artificial blood vessel VE is not necessarily limited to the woven structure shown in FIG. 3, and may have other woven structures.

[0022] In this embodiment, the artificial blood vessel VE has a first region R1 in which warp threads 1 and weft threads 2 are woven in a plain weave, as shown in Figure 3. Furthermore, on one side of the artificial blood vessel VE (in this embodiment, the outer surface (front) of the artificial blood vessel VE), the artificial blood vessel VE has a second region R2 having a first portion R21 on the second region side where the warp threads 1 span multiple weft threads 2 (a portion extending across multiple weft threads 2), and a second portion R22 on the second region side where the warp threads 1 span across one weft thread 2 (a portion extending across one weft thread 2). Furthermore, the artificial blood vessel VE has a third region R3 on one side of the artificial blood vessel VE (in this embodiment, the outer surface of the artificial blood vessel VE) which has a first portion R31 on the third region side where the warp thread 1 spans multiple weft threads 2 (a portion extending across multiple weft threads 2), and a second portion R32 on the third region side where the warp thread 1 spans one weft thread 2 (a portion extending across one weft thread 2). The first region R1, the second region R2, and the third region R3 are formed alternately in the direction of extension D2 of the weft threads 2, as shown in Figure 3. That is, the first region R1, the second region R2, and the third region R3 are repeatedly arranged in this order in the direction of extension D2 of the weft threads 2. The first portion R21 on the second region side is adjacent to the second portion R32 on the third region side in the direction D2 of the extension of the weft 2, and the second portion R22 on the second region side is adjacent to the first portion R31 on the third region side in the direction D2 of the extension of the weft 2. In this embodiment, the warp 1 is composed of multifilament yarn. When the artificial blood vessel VE of this embodiment has the above configuration, as will be described later, the warp 1, composed of multifilament yarn that extends long without being constrained in the first portion R21 on the second region side or the first portion R31 on the third region side, spreads into the first region R1 which is woven in plain weave. Due to the three-dimensional structure of this warp 1, when blood seeps out from the interfiber gaps that occur in the first region R1 which is woven in plain weave, the blood leakage is suppressed and the blood is retained within the three-dimensional structure. The blood coagulates in this retained state, which improves blood leakage resistance. The configuration and weave structure of each part of the artificial blood vessel VE will be described below.

[0023] Warp threads 1 are fibers that extend in one direction among the fibers constituting the artificial blood vessel VE. In this embodiment, warp threads 1 are fibers that extend along the length direction (axis X direction) of the artificial blood vessel VE. Warp threads 1 are made of a material applicable to fabric artificial blood vessels, which are constructed by the weave structure of the fibers. The material of warp threads 1 is not particularly limited as long as it is a material applicable to fabric artificial blood vessels. For example, the material of warp threads 1 can be polyester, polytetrafluoroethylene, polyamide, etc. Alternatively, a composite material composed of two or more applicable materials with different properties such as melting point and stretchability may be used as the material of warp threads 1. For example, the material of warp threads 1 can be a synthetic fiber formed by compounding polyethylene terephthalate (PET) and polytrimethylene terephthalate (PTT), etc., during the spinning stage to form a single long fiber with a helical crimp. For example, if a composite material composed of two materials having different melting points and expansion rates, and possessing a helical crimp, is used as the material for the warp thread 1, the three-dimensional structure formed by the warp thread 1, as described later, will spread more easily in the direction D2 of the weft thread 2, thereby improving the blood retention performance and enhancing resistance to blood leakage.

[0024] Each of the warp threads 1 may be a monofilament yarn or a multifilament yarn, but in this embodiment, the warp threads 1 are composed of multifilament yarns. When the warp threads 1 are monofilament yarns, the weft threads 2 are composed of multifilament yarns. The fineness of the warp threads 1 is not particularly limited, but for example, when the warp threads 1 are monofilament yarns, the single-ply fineness of the warp threads can be 15 to 100 dtex, preferably 20 to 75 dtex. When the warp threads 1 are multifilament yarns, for example, the single-ply fineness of the warp threads 1 can be 0.25 to 2.50 dtex, preferably 0.50 to 2.00 dtex, and the total fineness of the warp threads 1 can be 2 to 2500 dtex, preferably 6 to 1600 dtex, more preferably 10 to 540 dtex, and even more preferably 30 to 200 dtex. By setting the single filament fineness of warp thread 1 and the total fineness of warp thread 1 within the above range, warp thread 1 in the second region R2 and the third region R3 can be effectively spread toward the first region R1. Therefore, when blood seeps out from the gap in the first region R1 due to warp thread 1 in the second region R2 and the third region R3, leakage of the blood is suppressed, and it is held in place by the three-dimensional structure of warp thread 1. The blood then coagulates in this held state, thereby improving blood leakage resistance. Note that "single filament fineness" is the fineness per filament constituting warp thread 1, and "total fineness" is the product of the single filament fineness and the number of filaments constituting warp thread 1. The number of filament threads constituting one warp thread (hereinafter referred to as the number of filaments) is not particularly limited, but for example, as will be described later, if the total number of filaments of warp thread 1 is 1.5 times or more the number of filaments per weft thread 2, and in the second region R2, the number of warp threads of warp thread 1 that spans multiple weft threads 2 is 1, then the number of filaments per warp thread 1 can be 8 to 1000, preferably 12 to 800, more preferably 20 to 270, and even more preferably 60 to 100.As will be described later, if the number of filaments per warp thread 1 is 0.8 to 1.2 times the number of filaments per weft thread 2, and in the second region R2, there are two or more warp threads of warp thread 1 that span multiple weft threads 2, then the number of filaments per warp thread 1 can be 4 to 500, preferably 6 to 400, more preferably 10 to 135, and even more preferably 30 to 50.

[0025] The weft 2 is a fiber that extends in a direction intersecting the warp 1 among the fibers constituting the artificial blood vessel VE. In this embodiment, the weft 2 is a fiber that extends in the circumferential direction of the artificial blood vessel VE. The weft 2 is made of a material applicable to fabric artificial blood vessels, which are constructed by the weave structure of the fibers. The material of the weft 2 is not particularly limited as long as it is a material applicable to fabric artificial blood vessels. For example, the material of the weft 2 can be polyester, polytetrafluoroethylene, polyamide, etc.

[0026] Each of the weft threads 2 may be a monofilament yarn or a multifilament yarn, but in this embodiment, the weft threads 2 are made of multifilament yarns. When the weft threads 2 are monofilament yarns, the warp threads 1 are made of multifilament yarns. The fineness of the weft threads 2 is not particularly limited, but for example, when the weft threads 2 are monofilament yarns, the single-ply fineness of the weft threads can be 15 to 100 dtex, preferably 20 to 75 dtex. When each of the weft threads 2 are made of multifilament yarns, for example, the single-ply fineness of the weft threads 2 can be 0.25 to 2.50 dtex, preferably 0.50 to 2.00 dtex, and the total fineness of the weft threads 2 can be 1 to 1250 dtex, preferably 3 to 800 dtex, more preferably 5 to 270 dtex, and even more preferably 15 to 100 dtex. "Single filament fineness" refers to the fineness of each filament (monofilament or multifilament) that makes up the weft yarn 2, and "total fineness" is the product of the single filament fineness and the number of filaments that make up the weft yarn 2. When the weft yarn 2 is made up of multifilament yarn, the number of filaments that make up one weft yarn can be 4 to 500, preferably 6 to 400, more preferably 10 to 135, and even more preferably 30 to 50.

[0027] The first region R1 is the area where warp threads 1 and weft threads 2 are woven in a plain weave. In Figure 3, the first region R1 is the area where warp threads 1a, 1b, 1e, 1f, 1i, 1j and weft threads 2 (weft threads 2a to 2l) intersect. In the plain weave structure of the first region R1, warp threads 1 extend so as shown in Figure 4, crossing only one weft thread 2 (not crossing multiple weft threads 2) from one surface of the artificial blood vessel VE (the outer surface of the artificial blood vessel VE; the upper surface in Figure 4) to the other surface (the inner surface of the artificial blood vessel VE; the lower surface in Figure 4), and from the other surface to the first surface. The first region R1 improves the strength of the artificial blood vessel VE, especially its tensile strength (in the axial X direction of the artificial blood vessel VE). The first region R1 extends along the extension direction D1 of warp threads 1 and extends in the axial X direction of the artificial blood vessel VE. Furthermore, multiple first regions R1 are arranged at predetermined intervals from each other in the direction D2 of the weft yarn 2. In the direction D2 of the weft yarn 2, a second region R2 and a third region R3 are arranged between one first region R1 and another first region R1.

[0028] In this embodiment, as shown in Figure 3, the first region R1 is plain woven with two warp threads 1a, 1b (warp threads 1e, 1f or warp threads 1i, 1j) and a plurality of weft threads 2a to 2l (and weft threads not shown). The number of warp threads 1 provided in one first region R1 can be 2 to 4, preferably 2 to 3, and more preferably 2. In this specification, when the warp thread 1 is a multifilament yarn, "number of warp threads" refers not to the number of filaments that make up the multifilament yarn, but to the number of warp threads 1 that are made up of multiple filament threads and bundled together. By setting the number of warp threads 1 within the above range, the area of ​​the first region R1 that is not covered by the warp threads 1 of the first part R21 on the second region side and the warp threads 1 of the first part R31 on the third region side can be reduced. Therefore, the plain weave first region R1 is more easily covered three-dimensionally by the warp threads 1 of the first portion R21 on the second region side and the warp threads 1 of the first portion R31 on the third region side. When blood seeps out from the first region R1, the blood is held in place by the three-dimensional structure of the warp threads 1 of the first portion R21 on the second region side and the warp threads 1 of the first portion R31 on the third region side. Since the blood coagulates in this held state, the amount of blood leakage from the artificial blood vessel VE can be reduced. Furthermore, in the artificial blood vessel VE, the ratio of the number of warp threads in the first region R1 to the total number of warp threads arranged in the extending direction D2 of the weft threads 2 in the first region R1 to the third region R3 (number of warp threads in the first region R1 / total number of warp threads) is not particularly limited, but can be, for example, 0.2 to 0.4 (1 / 3 in this embodiment). By setting the number of warp threads and the ratio of warp threads in warp thread 1 in the first region R1 to the above range, it is possible to increase the strength of the artificial blood vessel VE while reducing the amount of blood leakage from the artificial blood vessel VE.

[0029] The second region R2 has a first portion R21 on the second region side where the warp thread 1 crosses over multiple weft threads 2, and a second portion R22 on the second region side where the warp thread 1 extends across a single weft thread 2. The first portion R21 and the second portion R22 on the second region side are arranged alternately in the direction D1 of the extension of the warp thread 1, as shown in Figure 3. Because the second region R2 has a first portion R21 and a second portion R22 on the second region side, the artificial blood vessel VE can be made more flexible compared to one in which the entire artificial blood vessel VE is a plain weave structure. The portion of warp thread 1c provided in the second region R2 may be composed of one warp thread or multiple warp threads. The number of warp threads 1 provided in the second region R2 can be, for example, 1 to 4, preferably 2 to 3, and more preferably 2.

[0030] The first portion R21 on the second region side is a portion woven such that the warp threads 1 have portions that cross over multiple weft threads 2. In this embodiment, warp threads 1c, 1g, 1k, etc., cross over multiple weft threads 2. In the first portion R21 on the second region side, the warp threads 1 crossing over multiple weft threads 2 makes the artificial blood vessel VE more flexible in that portion than in a plain weave structure. Furthermore, if the warp threads 1 of the first portion R21 on the second region side are composed of multifilament yarns, both ends of the first portion R21 on the second region side are bound by the weft threads 2 of the second portion R22 on the second region side (see portion P1 in Figure 3) in the extension direction D1 of the warp threads 1. In that case, the first portion R21 on the second region side of the warp threads 1 composed of multifilament yarns with both ends bound forms a three-dimensional structure in which the central part in the extension direction D1 of the warp threads 1 extends in the extension direction D2 of the weft threads 2 (this three-dimensional structure also extends in the left-right direction and the front-of-page direction in Figure 3). Therefore, the first region R1, which has a plain weave structure and is adjacent to the first portion R21 of the second region in the extension direction D2 of the weft 2, is partially covered by the multifilament threads of the expanded first portion R21 of the second region. Due to the three-dimensional structure of the warp 1, when blood seeps out from the interfiber gaps that occur in the plain weave first region R1, the seeped blood is held in the gaps between the filaments of the three-dimensional structure made up of multifilaments. As a result, the blood coagulates in the held state, improving resistance to blood leakage. In addition, in this embodiment, the second portion R32 of the third region, which is adjacent to the first portion R21 of the second region in the extension direction D2 of the weft 2, is similarly partially covered by the multifilament threads of the expanded first portion R21 of the second region. As a result, the gaps that occur in the second portion R32 of the third region are also covered by the multifilament threads of the first portion R21 of the second region, making it difficult for blood in the artificial blood vessel VE to leak out.

[0031] In the first portion R21 on the second region side (from when the warp thread 1 emerges from one side of the artificial blood vessel VE onto one side (the side shown in Figure 3) to when it reaches the other side), the number of weft threads that the warp thread 1 crosses over the weft thread 2 is not particularly limited, but can be, for example, 2 to 5 threads, preferably 3 to 4 threads, and more preferably 3 threads (as shown in Figure 3). By setting the number of weft threads that the warp thread 1 crosses over the weft thread 2 in the first portion R21 on the second region side to the above range, the multifilament threads of the warp thread 1 can be easily spread in the extending direction D2 of the weft thread 2, and the artificial blood vessel VE can be maintained at a predetermined strength.

[0032] The number of warp threads 1 constituting the first part R21 on the second region side is not particularly limited, as long as the warp thread 1 has a portion that spans multiple weft threads 2. For example, the first part R21 on the second region side (second region R2) may be composed of multiple (2) warp threads (each of warp threads 1c, 1g, and 1k is composed of multiple warp threads). Also, the first part R21 on the second region side (second region R2) may have at least one warp thread 1 that extends across one (only) weft thread 2, and at least one warp thread 1 that spans multiple weft threads 2.

[0033] The second portion R22 on the second region side is a portion woven such that warp thread 1 crosses over only one weft thread 2 (warp thread 1 does not cross over multiple weft threads 2 from the point where it emerges from one side of the artificial blood vessel VE to the other side). The length of the second portion R22 on the second region side is approximately the same as the length of the first portion R21 on the second region side in the direction of extension D1 of warp thread 1. That is, the number of weft threads 2 in the first portion R21 on the second region side (3 in Figure 3) is equal to the number of weft threads 2 in the second portion R22 on the second region side (3 in Figure 3).

[0034] The third region R3 has a first portion R31 on the third region side where the warp thread 1 crosses over multiple weft threads 2, and a second portion R32 on the third region side where the warp thread 1 extends across a single weft thread 2. The first portion R31 and the second portion R32 on the third region side are arranged alternately in the direction D1 of the extension of the warp thread 1, as shown in Figure 3. Because the third region R3 has a first portion R31 and a second portion R32 on the third region side, the artificial blood vessel VE can be made more flexible compared to one in which the entire artificial blood vessel VE is a plain weave structure. The portion of warp thread 1d provided in the third region R3 may be composed of one warp thread or multiple warp threads. The number of warp threads 1 provided in the third region R3 can be, for example, 1 to 4, preferably 2 to 3, and more preferably 2.

[0035] The first portion R31 on the third region side is a portion woven such that the warp threads 1 have portions that cross over multiple weft threads 2. In this embodiment, warp threads 1d, 1h, 1l, etc., cross over multiple weft threads 2. In the first portion R31 on the third region side, the warp threads 1 crossing over multiple weft threads 2 makes the artificial blood vessel VE more flexible in that portion than in a plain weave structure. Furthermore, if the warp threads 1 of the first portion R31 on the third region side are composed of multifilament yarns, both ends of the first portion R31 on the third region side are bound by the weft threads 2 of the second portion R32 on the third region side (see portion P2 in Figure 3) in the extension direction D1 of the warp threads 1. In that case, the first portion R31 on the third region side of the warp threads 1 composed of multifilament yarns with both ends bound forms a three-dimensional structure in which the central part in the extension direction D1 of the warp threads 1 extends in the extension direction D2 of the weft threads 2. Therefore, the first region R1, which is a plain weave structure adjacent to the first portion R31 on the third region side in the extension direction D2 of the weft 2, is partially covered by the multifilament threads of the expanded first portion R31 on the third region side. Due to the three-dimensional structure of the warp 1, when blood seeps out from the interfiber gaps that occur in the plain weave first region R1, the seeped blood is held in the gaps between the filaments of the three-dimensional structure composed of multifilaments. As a result, the blood coagulates in the held state, improving resistance to blood leakage. In addition, in this embodiment, the second portion R22 on the second region side, which is adjacent to the first portion R31 on the third region side in the extension direction D2 of the weft 2, is similarly partially covered by the multifilament threads of the expanded first portion R31 on the third region side. As a result, the gaps that occur in the second portion R22 on the second region side are also covered by the multifilament threads of the first portion R31 on the third region side, making it difficult for blood in the artificial blood vessel VE to leak out.

[0036] In the first portion R31 on the third region side (from when the warp thread 1 emerges from one side of the artificial blood vessel VE onto one side (the side shown in Figure 3) to when it reaches the other side), the number of weft threads that the warp thread 1 crosses over the weft thread 2 is not particularly limited, but can be, for example, 2 to 5 threads, preferably 3 to 4 threads, and more preferably 3 threads (as shown in Figure 3). By setting the number of weft threads that the warp thread 1 crosses over the weft thread 2 in the first portion R31 on the third region side to the above range, the multifilament threads of the warp thread 1 can be easily spread in the extending direction D2 of the weft thread 2, and the artificial blood vessel VE can be maintained at a predetermined strength.

[0037] The number of warp threads 1 constituting the first part R31 on the third region side is not particularly limited, as long as the warp thread 1 has a portion that spans multiple weft threads 2. For example, the first part R31 on the third region side (third region R3) may be composed of multiple (2) warp threads (each of warp threads 1d, 1h, and 1l is composed of multiple warp threads). Also, the first part R31 on the third region side (third region R3) may have at least one warp thread 1 that extends across one (only) weft thread 2, and at least one warp thread 1 that spans multiple weft threads 2.

[0038] The second portion R32 on the third region side is a section woven such that warp thread 1 crosses over only one weft thread 2 (warp thread 1 does not cross over multiple weft threads 2 from the point where it emerges from one side of the artificial blood vessel VE to one side (the side shown in Figure 3) to the other side). The second portion R32 on the third region side is approximately the same length as the first portion R31 on the third region side in the direction of extension D1 of warp thread 1. That is, the number of weft threads 2 in the first portion R31 on the third region side (3 in Figure 3) is the same as the number of weft threads 2 in the second portion R32 on the third region side (3 in Figure 3).

[0039] As shown in Figures 5 and 6, the artificial blood vessel VE of this embodiment has multiple covering portions C provided at multiple locations on the surface of the artificial blood vessel VE, each covering the multifilament thread in a planar manner, and uncovered portions UC provided between the multiple covering portions C on the surface of the artificial blood vessel VE and not covered by the covering portions C.

[0040] The covering portion C partially covers multiple filaments of a multifilament thread that constitutes one warp or one weft thread on the surface of the artificial blood vessel VE. "Covering the multifilament thread in a planar manner" means that the covering portion C extends on the surface of the artificial blood vessel VE in the direction of extension of the multifilament thread (extension direction D1 of warp thread 1) and in a direction perpendicular to the extension direction of the multifilament thread (extension direction D2 of weft thread 2) so as to seal the gaps on the surface side of the artificial blood vessel VE between multiple adjacent filaments that constitute the multifilament thread. As will be described in detail later, the presence of the covering portion C seals the gaps between multiple filaments located inside the covering portion C in the radial direction of the artificial blood vessel VE on the surface of the artificial blood vessel VE. This improves the blood leakage resistance of the artificial blood vessel VE.

[0041] The covering portion C is provided at multiple locations on the surface of the artificial blood vessel VE, as shown in Figures 5 and 6. Here, "multiple locations" means that when the entire surface of the artificial blood vessel VE is divided into multiple parts, the covering portion C is provided at multiple parts. The covering portion C may be provided at multiple locations separately from each other, or it may be provided at multiple locations continuously from each other in the axial direction (extension direction D1 of the warp thread 1) and / or circumferential direction (extension direction D2 of the weft thread 2) of the artificial blood vessel VE.

[0042] The uncovered portion UC, as shown in Figure 6, is the portion of the artificial blood vessel VE that is not covered by the covering portion C. The uncovered portion UC is located between multiple covering portions C, as shown in Figure 6. The uncovered portion UC is located between the covering portions C, for example, in the axial direction (extension direction D1 of warp 1) and / or circumferential direction (extension direction D2 of weft 2) of the artificial blood vessel VE. As will be described in detail later, the uncovered portion UC, by being located between the covering portions C on the surface of the artificial blood vessel VE, contributes to maintaining the flexibility of the artificial blood vessel VE. In this embodiment, the multifilament threads of warp 1 and weft 2 in the region of the uncovered portion UC are exposed on the surface of the artificial blood vessel VE while maintaining the gaps between adjacent filament threads (see Figure 6).

[0043] As described above, the artificial blood vessel VE of this embodiment has multiple covering portions C provided at multiple locations on the surface of the artificial blood vessel VE, each covering multiple multifilament threads in a planar manner, and uncovered portions UC provided between the multiple covering portions C on the surface of the artificial blood vessel VE and not covered by the covering portions C. As a result, the gaps between the multiple filament threads constituting the multifilament threads are sealed by the covering portions C, thereby improving the blood leakage resistance of the artificial blood vessel VE. Furthermore, by providing uncovered portions UC between the multiple covering portions C, the flexibility of the artificial blood vessel VE as a whole can be maintained. Therefore, according to the artificial blood vessel VE of this embodiment, it is possible to improve blood leakage resistance while maintaining the flexibility of the artificial blood vessel VE.

[0044] The ratio of the covering portion C to the surface area of ​​the artificial blood vessel VE is not particularly limited, but it is preferable that the total area of ​​the multiple covering portions C is 50-90%, more preferably 60-80%, of the surface area of ​​the artificial blood vessel VE. In this case, the blood leakage resistance of the artificial blood vessel VE can be further improved while maintaining the flexibility of the artificial blood vessel VE.

[0045] Furthermore, in this embodiment, as shown in Figure 5, the artificial blood vessel VE has an inner woven section IW extending radially inward (downward in Figure 5) relative to the covering section C, where multiple filaments of the multifilament thread are separated from each other. The inner woven section IW constitutes part of the woven structure of the artificial blood vessel VE, and is covered by the covering section C with multiple filaments separated from each other with gaps between them. The multiple filaments of the inner woven section IW are schematically shown in Figure 5, but they extend in a bundle shape, with multiple filaments adjacent to each other in the radial direction (up and down direction in Figure 5) of the artificial blood vessel VE, and multiple filaments adjacent to each other in the extension direction D2 of the weft thread 2 (depth direction of the paper in Figure 5). Note that in Figure 6, the inner woven section IW is covered by the covering section C and is not visible, but it is located in the depth direction of the paper relative to the covering section C. The structure of the inner woven section IW is not particularly limited as long as multiple filaments extend radially inward of the artificial blood vessel VE relative to the covering section C, while being separated from each other. In this embodiment, the inner woven section IW has a structure in which multifilament threads in the region corresponding to the first portion R21 on the second region side (and the first portion R31 on the third region side) spread out in the extending direction D2 of the weft thread 2, and the multiple filament threads constituting the multifilament threads of the inner woven section IW extend along the extending direction D1 of the warp thread 1 in a scattered state. In this embodiment, as shown in Figure 5, the warp thread 1 has a two-layer structure in the region corresponding to the first portion R21 on the second region side (and the first portion R31 on the third region side), consisting of a covering portion C which is a planar resin layer on the surface side of the artificial blood vessel VE, and the inner woven section IW which is a multifilament layer located radially inward from the covering layer C.

[0046] Because the inner woven layer (IW) is located radially inward of the covering layer C, multiple filament threads extend radially inward of the planar covering layer C in a separated state with gaps between them. Therefore, the inner woven layer (IW), composed of multifilament threads covered by the covering layer C, extends while maintaining a predetermined flexibility. Consequently, even with the presence of the planar covering layer C, the overall flexibility of the artificial blood vessel (VE) is not easily impaired, making it possible to achieve both flexibility and blood leakage resistance in the artificial blood vessel (VE). Furthermore, the presence of the inner woven layer (IW) allows the internal structure of the artificial blood vessel to maintain its woven structure, thereby suppressing impairment of cell invasion.

[0047] Furthermore, it is preferable that the covering portion C and the uncovered portion UC are alternately provided on a part of the surface of the artificial blood vessel VE in the axial direction (extension direction D1 of the warp thread 1) and / or circumferential direction (extension direction D2 of the weft thread 2) of the artificial blood vessel VE. In this case, the covering portion C and the uncovered portion UC are arranged in a balanced manner in the axial direction and / or circumferential direction of the artificial blood vessel VE. Therefore, the flexibility and blood leakage resistance of the artificial blood vessel VE are improved in a balanced manner, and local hardening or localized susceptibility to blood leakage of the artificial blood vessel VE is suppressed. In particular, when the covering portion C and the uncovered portion UC are alternately provided in the axial direction of the artificial blood vessel VE, the artificial blood vessel VE becomes easier to bend, and the arrangement of the artificial blood vessel VE in the body becomes easier. Also, when the covering portion C and the uncovered portion UC are alternately provided in the circumferential direction of the artificial blood vessel VE, the artificial blood vessel VE becomes easier to twist, and deformation (crushing) when the artificial blood vessel VE is twisted is suppressed. Therefore, even if the artificial blood vessel VE is subjected to a twisting force, such as when screwing it into a cardiopulmonary bypass machine, the crushing of the artificial blood vessel VE due to twisting is suppressed. Consequently, the harmful effects of twisting of the artificial blood vessel VE, such as blood clotting at the crushed area and subsequent occlusion of the artificial blood vessel VE, are suppressed. In this embodiment, the artificial blood vessel VE has a covered portion C and an uncovered portion UC alternately provided in both the axial and circumferential directions of the artificial blood vessel VE. In this case, the flexibility and blood leakage resistance of the artificial blood vessel VE are improved in a well-balanced manner throughout the entire artificial blood vessel VE.

[0048] The region in which the covering portion C is provided is not particularly limited, as long as the covering portion C is provided in multiple locations on the surface of the artificial blood vessel VE with a predetermined area. In this embodiment, as shown in Figure 5, the covering portion C is provided in portions R21 and R31 of the warp 1 that extend across multiple weft 2 (only portion R21 extending across multiple weft 2 is shown in Figure 5). More specifically, the covering portion C is provided in portions corresponding to the first portion R21 on the second region side and the first portion R31 on the third region side. Note that the covering portion C does not necessarily need to cover all of the multiple filament threads provided in portions that extend across multiple weft 2 (first portion R21 on the second region side and first portion R31 on the third region side), but only needs to cover the majority of the multiple filament threads (not limited to, for example, 50% or more, preferably 80% or more).

[0049] As described above, the portions R21 and R31 of the warp thread 1 that extend across multiple weft threads 2 make the artificial blood vessel VE more flexible in portions R21 and R31 than an artificial blood vessel with only a plain weave structure. Furthermore, both ends of portions R21 and R31 that extend across multiple weft threads 2 are bound by the weft threads 2 (see portions P1 and P2 in Figure 3). In this case, portions R21 and R31 that extend across multiple weft threads 2, which are composed of multifilament threads bound at both ends, form a three-dimensional structure in which the central part in the extension direction D1 of the warp thread 1 spreads out in the extension direction D2 of the weft threads 2. Thus, portions R21 and R31 that extend across multiple weft threads 2 have high blood retention due to their flexibility and three-dimensional structure, and their resistance to blood leakage is further improved by being covered by the covering portion C. Therefore, the flexibility and resistance to blood leakage of the artificial blood vessel VE are further improved.

[0050] The structure of the covering portion C is not particularly limited as long as it can cover the multifilament threads in a planar manner. In this embodiment, the covering portion C is composed of a resin layer that is either melted and solidified from the multifilament threads or coated on the surface of the multifilament threads. "Melted and solidified from the multifilament threads" refers to a state in which a portion of the multifilament threads constituting the warp thread 1 and / or weft thread 2 are melted by heating or the like, and then solidified to form a planar resin layer. In this case, the planar covering portion C, which is a melted and solidified resin layer, covers multiple filament threads that are not melted on the surface of the artificial blood vessel VE. "Resin layer coated on the surface" refers to a resin layer formed by coating the multifilament threads constituting the warp thread 1 and / or weft thread 2 with a resin material in a planar manner.

[0051] The method for manufacturing an artificial blood vessel (VE) is not particularly limited, but if the covering portion C is composed of a resin layer in which multifilament threads have been melted and solidified, it can be manufactured, for example, by the following method. First, a base material having a predetermined woven structure (see, for example, the woven structure in Figure 3) that constitutes the artificial blood vessel (VE) is prepared. Next, before processing the base material into a cylindrical shape, a heating medium is brought into contact with the surface of the base material that will become the outer surface (surface) of the artificial blood vessel (VE), depending on the position where the covering portion C will be provided. The heated heating medium melts a portion of the multifilament threads on the surface of the base material, and as it cools and solidifies, a covering portion C with a desired pattern is formed. Next, the base material is processed into a cylindrical shape to manufacture the artificial blood vessel (VE). Note that heating of the base material with the heating medium may be performed after the base material has been processed into a cylindrical shape. During the heating process of the substrate using a heating medium (a process in which a portion of the multifilament yarn is melted), the temperature and heating time of the heating medium are adjusted so that, in the thickness direction of the substrate, a portion of the outer surface (surface layer) of the multifilament yarn melts, but the inner surface of the artificial blood vessel VE does not melt in the thickness direction. As a result, the portion of the multifilament yarn of the substrate on the inner surface of the artificial blood vessel VE remains in a state where multiple filaments are separated. This results in an artificial blood vessel VE having a two-layer structure of a covering portion C and an inner woven portion IW. When manufacturing an artificial blood vessel VE having peaks M and valleys V, for example, in addition to the above process, a cylindrical substrate can be placed on the outside of a cylindrical core material, and then a wire can be wrapped around the outside of the artificial blood vessel VE at positions corresponding to the valleys V and heated to manufacture an artificial blood vessel VE having peaks M and valleys V. When coating the surface of the multifilament yarn with a resin layer, instead of the above-described heating process of the substrate (a process in which a portion of the multifilament yarn is melted), the covering portion C can be formed by applying a resin material to the surface of the multifilament yarn in a desired pattern using a known method. It should be noted that the above-described method for manufacturing artificial blood vessels (VE) is merely one example, and the artificial blood vessels (VE) are not limited to those manufactured using this method.

[0052] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The above embodiments mainly describe an invention having the following configuration.

[0053] (1) An artificial blood vessel having a predetermined woven structure in which warp and weft threads are woven, At least one of the warp and weft threads is composed of a multifilament yarn containing multiple filament threads, The aforementioned artificial blood vessel is Multiple covering portions are provided on the surface of the artificial blood vessel, each covering the multifilament thread in a planar manner, On the surface of the artificial blood vessel, there are uncovered portions provided between a plurality of covering portions and not covered by the covering portions. An artificial blood vessel.

[0054] (2) The artificial blood vessel according to (1), wherein the artificial blood vessel has an inner woven portion extending radially inward of the artificial blood vessel relative to the covering portion, in which the plurality of filament threads of the multifilament thread are separated from each other.

[0055] (3) The artificial blood vessel according to (1) or (2), wherein the covered portion and the uncovered portion are alternately provided on a part of the surface of the artificial blood vessel in the axial direction and / or circumferential direction of the artificial blood vessel.

[0056] (4) The artificial blood vessel according to any one of (1) to (3), wherein the total area of ​​the plurality of covering portions is 50 to 90%, preferably 60 to 80%, of the surface area of ​​the artificial blood vessel.

[0057] (5) The artificial blood vessel according to any one of (1) to (4), wherein the covering portion is composed of the multifilament thread in a molten and solidified state, or of a resin layer coated on the surface of the multifilament thread.

[0058] (6) The warp threads extend along the length of the artificial blood vessel, The warp threads are composed of the multifilament threads, The warp thread has a portion that extends across multiple weft threads, The covering portion is provided in the portion that extends across the plurality of weft threads. An artificial blood vessel described in any one of (1) to (5).

[0059] (7) The artificial blood vessel according to any one of (1) to (6), wherein the artificial blood vessel has alternating peaks and valleys formed in the axial direction of the artificial blood vessel. [Explanation of Symbols]

[0060] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l warp threads 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2l weft C Covering part D1 Direction of warp extension (axial direction of artificial blood vessel) D2 Direction of weft extension (circumferential direction of the artificial blood vessel) IW Inner Oribe M Yamabe The summit of Mt. Yamabe P1 The weft threads that tie both ends of the first part on the second region side. P2 The weft threads that tie both ends of the first part on the third region side. PL, PL1, PL2 flat section R1 1st area R2 2nd area R21 Second region side, first part (part extending across multiple weft threads) R22 Second region side, second part (the part that extends across a single weft thread) R3 3rd area R31 Third Region Side First Part (Part extending across multiple weft threads) R32 Third region side, second part (the part that extends across a single weft thread) UC uncoated section V Tanibe Vb Bottom of the valley VE Artificial Blood Vessel X Axis of the artificial blood vessel θ is the angle between one planar surface and the other planar surface.

Claims

1. An artificial blood vessel having a predetermined woven structure in which warp and weft threads are woven, At least one of the warp and weft threads is composed of a multifilament yarn containing multiple filament threads, The aforementioned artificial blood vessel is Multiple covering portions are provided on the surface of the artificial blood vessel, each covering the multifilament thread in a planar manner, On the surface of the artificial blood vessel, there are uncovered portions provided between a plurality of covering portions and not covered by the covering portions. It has, The covering portion is an artificial blood vessel in which the multifilament threads are in a melted and solidified state.

2. The artificial blood vessel according to claim 1, wherein the artificial blood vessel has an inner woven portion extending radially inward of the artificial blood vessel relative to the covering portion, in which the plurality of filament threads of the multifilament thread are separated from each other.

3. The artificial blood vessel according to claim 1, wherein the covering portion and the uncovered portion are alternately provided on a part of the surface of the artificial blood vessel in the axial direction and / or circumferential direction of the artificial blood vessel.

4. The artificial blood vessel according to claim 1, wherein the total area of ​​the plurality of covering portions is 50 to 90% of the surface area of ​​the artificial blood vessel.

5. The warp threads extend along the longitudinal direction of the artificial blood vessel, The warp threads are composed of the multifilament threads, The warp thread has a portion that extends across multiple weft threads, The covering portion is provided in the portion that extends across the plurality of weft threads. The artificial blood vessel according to claim 1.

6. The artificial blood vessel according to claim 1, wherein the artificial blood vessel has alternating peaks and valleys formed in the axial direction of the artificial blood vessel.

7. An artificial blood vessel having a predetermined woven structure in which warp threads and weft threads are woven, At least one of the warp and weft threads is composed of a multifilament yarn containing multiple filament threads, The aforementioned artificial blood vessel is Multiple covering portions are provided on the surface of the artificial blood vessel, each covering the multifilament thread in a planar manner, On the surface of the artificial blood vessel, there are uncovered portions provided between a plurality of covering portions and not covered by the covering portions. It has, The warp threads extend along the longitudinal direction of the artificial blood vessel, The warp threads are composed of the multifilament threads, The warp thread has a portion that extends across multiple weft threads, The covering portion is provided in the portion that extends across the plurality of weft threads. Artificial blood vessels.

Images