Access port, method for manufacturing access port, vascular access device, catheter cuff, and catheter

Abstract

The purpose of the present invention is to provide an access port capable of reducing or preventing progression of down-growth, a method for manufacturing the same, and a vascular access device. The purpose of the present invention is also to provide a catheter cuff and a catheter capable of achieving the above. An access port (92) includes: a vascular access part (921) including a first surface (923) for being pierced with a needle and a second surface (924) from which the needle emerges; and a peripheral part (926) surrounding the periphery of the vascular access part (921). The vascular access part (921) contains an elastomer, and the peripheral part (926) includes a porous body having communication holes. Meanwhile, a catheter cuff includes a porous body having communication holes.

Description

Access port, method of manufacturing access port, vascular access device, catheter cuff, and catheter

[0001] The present invention relates to an access port, a method for manufacturing an access port, a vascular access device, a cuff for a catheter, and a catheter.

[0002] Hemodialysis is typically performed three times a week, and needles are inserted each time, so it is desirable to avoid or reduce the pain of needle insertion.

[0003] An example of a device that can avoid or reduce the pain of puncture is the blood inlet / outlet device described in Patent Document 1. This blood inlet / outlet device allows for vascular access without the need to puncture a blood vessel through the skin, thereby avoiding the pain of puncture. The same applies to the access port described in Patent Document 2.

[0004] Japanese Unexamined Patent Publication No. 57-9458 Patent No. 4815024

[0005] These devices (i.e., the blood inlet / outlet device described in Patent Document 1 and the access port described in Patent Document 2) are placed in the living body in a manner that exposes the skin, which can lead to excessive downgrowth, a phenomenon in which the surrounding epidermis collapses. Downgrowth increases the risk of infection at the exit site.

[0006] An object of the present invention is to provide an access port, a method for manufacturing the same, and a vascular access device that can reduce or prevent the progression of downgrowth. Another object of the present invention is to provide a catheter cuff and a catheter that can reduce or prevent the progression of downgrowth.

[0007] To solve this problem, the access port of the present invention has the following configuration [1]: [1] An access port including a vascular access portion including a first surface to be pierced with a needle and a second surface from which the needle protrudes, and a peripheral portion surrounding the periphery of the vascular access portion, wherein the vascular access portion contains an elastomer, and the peripheral portion includes a porous body having communicating holes.

[0008] According to [1], since the vascular access portion contains an elastomer, when the needle is inserted into or removed from the vascular access portion, the hole made by the needle can be closed.

[0009] Furthermore, because the area surrounding the access port includes a porous body with interconnected pores, cells can enter the pores. In other words, biological tissue can infiltrate the pores. This allows the access port to heal with the epidermis, reducing or preventing downgrowth (i.e., the collapse of the epidermis along the access port).

[0010] The access port of the present invention preferably has the following configurations [2] to [9]. [2] The access port according to [1], wherein the peripheral portion further contains a biodegradable material having cell adhesive properties within the communicating pores. [3] The access port according to [2], wherein the biodegradable material is at least one of a cross-linked gelatin gel and collagen. [4] The access port according to [2], wherein the biodegradable material is a cross-linked gelatin gel. [5] The access port according to any of [1] to [4], wherein the porous body has at least one peak in a log differential pore volume distribution curve, the peak apex of which is in a pore size range of more than 100 μm to 1,000 μm. [6] The access port according to any of [1] to [5], wherein the porous body contains an elastomer. [7] The access port according to [6], wherein the elastomer is a thermoplastic polyurethane elastomer. [8] The access port according to any of [1] to [7], wherein the porous body has a tensile modulus of elasticity of 40 kPa or more and 190 kPa or less. [9] The access port described in any one of [1] to [8], wherein the peripheral portion includes an inner surface facing the vascular access portion and an outer surface opposite the inner surface, and the thickness from the inner surface to the outer surface is 0.5 mm or more and 2 mm or less.

[0011] The method for producing an access port according to the present invention comprises the following configuration

[10] :

[10] A method for producing the access port according to any one of [2] to [9], comprising the steps of: immersing an access port before immersion, which includes the vascular access portion and the porous body, in an aqueous solution containing a water-soluble biodegradable material having cell adhesive properties under a reduced pressure environment; increasing the atmospheric pressure of the aqueous solution in which the access port before immersion is immersed; and insolubilizing the water-soluble biodegradable material contained in the access port after immersion.

[0012] The vascular access device of the present invention has the following configuration

[11] :

[11] A vascular access device including the access port according to any one of [1] to [9] and an artificial blood vessel, wherein the second surface of the access port faces the artificial blood vessel.

[0013] The access port, the manufacturing method thereof, and the vascular access device of the present invention preferably have the following configuration:

[12] The area of ​​the first surface is 20 mm ２ or more than 30 mm ２

[13] The access port, the method for manufacturing the same, or the vascular access device according to any one of the above configurations, wherein the area of ​​the first surface is 180 mm ２ Less than or equal to 120 mm ２

[14] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the elastomer of the vascular access portion is a styrene-based thermoplastic elastomer.

[15] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the tensile modulus of the vascular access portion is 250 kPa or more or 300 kPa or more.

[16] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the tensile modulus of the vascular access portion is 1500 kPa or less or 1000 kPa or less.

[17] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the peripheral portion covers all surfaces of the vascular access portion except the first surface and the second surface.

[18] An access port, a manufacturing method thereof, or a vascular access device according to any of the preceding configurations, wherein the peripheral portion covers all surfaces of the vascular access portion except the first and second surfaces.

[19] An access port, a manufacturing method thereof, or a vascular access device according to any of the preceding configurations, wherein the porosity of the peripheral portion is 30% or less or 20% or less.

[20] An access port, a manufacturing method thereof, or a vascular access device according to any of the preceding configurations, wherein the porosity of the peripheral portion is 10% or less or 5% or less.

[21] An access port, a manufacturing method thereof, or a vascular access device according to any of the preceding configurations, wherein the porous body covers all surfaces of the vascular access portion except the first and second surfaces.

[22] An access port, a manufacturing method thereof, or a vascular access device according to any of the preceding configurations, wherein the porous body covers all surfaces of the vascular access portion except the first and second surfaces.

[23] The access port, the method for manufacturing the same, or the vascular access device according to any one of the above configurations, wherein the porosity of the porous body itself is 30% or more or 40% or more.

[24] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the porosity of the porous body itself is 70% or less or 65% or less.

[25] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the elastomer content of the porous body is 90% by mass or more or 95% by mass or more.

[26] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the elastomer content of the porous body is 97% by mass or more or 98% by mass or more.

[27] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the insoluble content of the biodegradable material, specifically the insoluble content in water, is 40% or more or 45% or more.

[28] An access port, a method for manufacturing the same, or a vascular access device according to any of the preceding configurations, wherein the insoluble content of the biodegradable material, specifically the insoluble content in water, is 70% or less or 60% or less.

[29] A method for producing an access port according to any of the above configurations, wherein the water-soluble biodegradable material is gelatin.

[30] A method for producing an access port according to any of the above configurations, wherein the reduced pressure environment is 25 kPa or less or 20 kPa or less.

[31] A method for producing an access port according to any of the above configurations, wherein the reduced pressure environment is 15 kPa or less.

[32] A method for producing an access port according to any of the above configurations, wherein in the step of immersing the access port before immersion in the aqueous solution under the reduced pressure environment, the temperature of the aqueous solution is 35°C or higher or 40°C or higher.

[33] A method for producing an access port according to any of the above configurations, wherein in the step of increasing the atmospheric pressure, the atmospheric pressure is increased to or above atmospheric pressure.

[34] A method for producing an access port according to any of the above configurations, further comprising the step of removing the access port after immersion from the aqueous solution.

[35] A method for producing an access port according to any of the above configurations, wherein in the step of insolubilizing the water-soluble biodegradable material, the access port after immersion is irradiated with an electron beam.

[36] The method for manufacturing an access port according to any one of the preceding configurations, wherein the electron beam dose is 20 kGy or more or 25 kGy or more.

[37] The method for manufacturing an access port according to any one of the preceding configurations, wherein the electron beam dose is 80 kGy or less or 45 kGy or less.

[38] The vascular access device according to any one of the preceding configurations, wherein the artificial blood vessel has an inner diameter of 4 mm or more or 5 mm or more.

[39] The vascular access device according to any one of the preceding configurations, wherein the artificial blood vessel has an inner diameter of 6 mm or less.

[40] The vascular access device according to any one of the preceding configurations, wherein the artificial blood vessel comprises a porous body having communicating holes.

[41] The vascular access device according to any one of the preceding configurations, wherein the porous body of the artificial blood vessel is tubular.

[42] The vascular access device according to any one of the preceding configurations, wherein the artificial blood vessel further comprises a biodegradable material having cell adhesive properties within the communicating holes.

[43] The vascular access device according to any one of the preceding configurations, wherein the biodegradable material of the artificial blood vessel is at least one of cross-linked gelatin gel and collagen.

[44] The vascular access device according to any one of the preceding configurations, wherein the porous body of the artificial blood vessel contains a thermoplastic elastomer.

[45] The vascular access device according to any one of the preceding configurations, wherein the porous body of the artificial blood vessel contains a thermoplastic polyurethane elastomer.

[0014] On the other hand, the catheter cuff of the present invention has the following configuration

[46] :

[46] A catheter cuff including a porous body having communicating holes.

[0015] According to

[46] , the cuff includes a porous body having interconnecting pores, allowing cells to enter the interconnecting pores. In other words, biological tissue can infiltrate the interconnecting pores. Therefore, the cuff can fuse with the epidermis, and the progression of downgrowth (i.e., the collapse of the epidermis along the catheter) can be reduced or prevented.

[0016] The catheter cuff of the present invention preferably has the following configuration:

[47] The catheter cuff according to

[46] , further comprising a biodegradable material having cell adhesive properties within the communicating holes.

[48] The catheter cuff according to

[46] or

[47] , wherein the tensile modulus of the porous body is 40 kPa or more and 190 kPa or less.

[0017] The catheter of the present invention has the following configuration

[49] :

[49] A catheter including a catheter cuff according to any one of

[46] to

[48] .

[0018] The catheter of the present invention preferably has the following configuration:

[50] The catheter according to

[15] , which is a continuous ambulatory peritoneal dialysis catheter or a central venous catheter.

[0019] The catheter cuff or catheter of the present invention also preferably has the following configurations.

[51] A catheter cuff or catheter according to any of the above configurations, wherein the porosity of the porous body itself is 30% or more or 40% or more.

[52] A catheter cuff or catheter according to any of the above configurations, wherein the porosity of the porous body itself is 70% or less or 65% or less.

[53] A catheter cuff or catheter according to any of the above configurations, wherein the porous body contains an elastomer.

[54] A catheter cuff or catheter according to any of the above configurations, wherein the elastomer is a thermoplastic polyurethane elastomer.

[55] A catheter cuff or catheter according to any of the above configurations, wherein the content of the elastomer in the porous body is 90% by mass or more or 95% by mass or more.

[56] A catheter cuff or catheter according to any of the above configurations, wherein the content of the elastomer in the porous body is 97% by mass or more or 98% by mass or more.

[57] A catheter cuff or catheter according to any of the above configurations, wherein the biodegradable material is at least one of cross-linked gelatin gel and collagen.

[58] A catheter cuff or catheter according to any of the preceding configurations, wherein the insoluble portion of the biodegradable material, specifically the insoluble portion in water, is 40% or more or 45% or more.

[59] A catheter cuff or catheter according to any of the preceding configurations, wherein the insoluble portion of the biodegradable material, specifically the insoluble portion in water, is 70% or less or 60% or less.

[60] A catheter cuff or catheter according to any of the preceding configurations, wherein the catheter cuff is cylindrical.

[61] A catheter cuff or catheter according to any of the preceding configurations, wherein the porous body has at least one peak in a log differential pore volume distribution curve, the peak apex of which is in the pore size range of more than 100 μm to 1,000 μm.

[62] A catheter according to any of the preceding configurations, further comprising a tube, wherein the catheter cuff is attached to the tube.

[0020] According to the present invention, it is possible to provide an access port that can reduce or prevent the progression of downgrowth, a method for manufacturing the same, and a vascular access device. According to the present invention, it is possible to provide a catheter cuff and a catheter that can reduce or prevent the progression of downgrowth.

[0021] 1A , 2A , 2B, 2C, 2D, 2E, 2F, 2G, 2G, 2H ... 6A is a schematic cross-sectional view of a vascular access device and its surroundings when the vascular access device according to a modified example of this embodiment is placed in a living body. 3B is a schematic cross-sectional view of the vascular access device and its surroundings as viewed in the direction of arrow IIIB shown in FIG. 3A. 3C is a schematic cross-sectional view of the vascular access device and its surroundings taken along section line IIIC shown in FIG. 3A. 3D is a schematic cross-sectional view of a vascular access device and its surroundings taken along section line IIIC shown in FIG. 3A. 3E is a schematic perspective view of a continuous ambulatory peritoneal dialysis (CAPD) catheter according to this embodiment. 3F is a schematic perspective view of a central venous catheter according to this embodiment. 6G is a graph of the log differential pore volume distribution of the polyurethane porous body of Preparation Example 1. 6H is a micrograph of the vicinity of the interface (specifically, the interface between the EL sheet and the porous membrane) in the laminate of Preparation Example A. The EL sheet is visible above the porous membrane. 6I is a micrograph of an enlarged area surrounded by a box shown in FIG. 6A. 6J is a micrograph of the vicinity of the interface (specifically, the interface between the EL sheet and the gelatin-treated membrane) in the laminate of Preparation Example B.An EL sheet is visible above the gelatin-treated membrane. This is a micrograph of the vicinity of the interface in the laminate of Preparation Example C (specifically, the interface between the EL sheet and the gelatin-treated membrane). An EL sheet is visible above the gelatin-treated membrane. This is a micrograph of the vicinity of the interface in the laminate of Preparation Example D (specifically, the interface between the EL sheet and the gelatin-treated membrane). An EL sheet is visible above the gelatin-treated membrane. On the left, an analysis range cut out from a micrograph of the cross section of the laminate to determine the porosity of the porous membrane of the laminate of Preparation Example A is shown. On the right, a binary image of this analysis range is shown. On the left, an analysis range cut out from a micrograph of the cross section of the laminate to determine the porosity of the gelatin-treated membrane of the laminate of Preparation Example B is shown. On the right, a binary image of this analysis range is shown. On the left, an analysis range cut out from a micrograph of the cross section of the laminate to determine the porosity of the gelatin-treated membrane of the laminate of Preparation Example C is shown. 1 shows a binary image of this analysis range on the right. On the left, an analysis range cut out from a micrograph of the cross section of the laminate in Preparation Example D to determine the porosity of the membrane after gelatin treatment of the laminate is shown. On the right, a binary image of this analysis range is shown. On the left, an analysis range cut out from a micrograph of the cross section of the laminate in Preparation Example E to determine the porosity of the porous membrane of the laminate is shown. On the right, a binary image of this analysis range is shown. This is a photograph of the apparatus used to produce a tubular polyurethane porous body in Example 1. The apparatus includes a cylindrical rod and a mold including an inner wall capable of forming a cylindrical cavity concentric with the rod. The mold includes a pair of half-frames. This photograph shows the apparatus after assembly. This is a photograph of the apparatus used to produce a tubular polyurethane porous body in Example 1. This photograph shows the apparatus with the pair of half-frames separated.

[0022] Hereinafter, embodiments of the present invention will be described in detail.

[0023] 1A, 1B, and 1C, the vascular access device 9 of this embodiment includes an artificial blood vessel 91 and an access port 92 protruding from the artificial blood vessel 91. The artificial blood vessel 91 and the access port 92 can be joined by any method. For example, they may be sewn together, joined with an adhesive, welded with a solvent, or welded with heat. Because the access port 92 is joined to the artificial blood vessel 91, the effort of joining them can be eliminated when placing the vascular access device 9.

[0024] 1.1 Access Port The access port 92 extends in a columnar shape from the outer surface (hereinafter sometimes referred to as the "outer surface") of the artificial blood vessel 91 to the side of the artificial blood vessel 91. The angle α formed between the access port 92 and the artificial blood vessel 91 may be, for example, 10 degrees or more, 30 degrees or more, 45 degrees or more, or 60 degrees or more. The angle α may be, for example, 90 degrees or less.

[0025] The access port 92 has a columnar shape. Although the figures show a cylindrical access port 92, the shape of the access port 92 may be, for example, a square columnar shape or a pentagonal columnar shape. In other words, the access port 92 may have a rectangular columnar shape.

[0026] The height H of the access port 92 may be 3 mm or more, or 5 mm or more, based on the outer surface of the artificial blood vessel 91. The height H of the access port 92 may be 25 mm or less, or 20 mm or less.

[0027] The length L of the access port 92 may be 3 mm or more, or 5 mm or more. The length L of the access port 92 may be 150 mm or less, or 120 mm or less. Here, the length L of the access port 92 refers to the maximum dimension of the access port 92 in the longitudinal direction of the artificial blood vessel 91.

[0028] The width W of the access port 92 may be 4 mm or more, or 5 mm or more. The width of the access port 92 may be 15 mm or less, or 12 mm or less. Here, the width W of the access port 92 refers to the maximum dimension of the access port 92 in the thickness direction of the artificial blood vessel 91. The width W of the access port 92 may be larger, smaller, or the same as the thickness of the artificial blood vessel 91.

[0029] The number of access ports 92 in the vascular access device 9 is one or more, and may be two or more. Of these, one access port 92 is preferred. Note that the vascular access device 9 can be cut as needed to adjust the length before placement, and in this paragraph, the number of access ports 92 refers to the number of access ports 92 before cutting.

[0030] The access port 92 includes a vascular access portion 921 and a peripheral portion 926 that surrounds the periphery of the vascular access portion 921 .

[0031] 1.1.1 Vascular Access Portion The vascular access portion 921 is columnar. Although the figures show a cylindrical vascular access portion 921, the shape of the vascular access portion 921 may be, for example, a square prism or a pentagonal prism. In other words, the shape of the vascular access portion 921 may be a prismatic prism.

[0032] The vascular access portion 921 includes a first surface 923 for being punctured with a needle and a second surface 924 from which the needle protrudes. The second surface 924 faces the artificial blood vessel 91. The second surface 924 is positioned closer to the artificial blood vessel 91 than the first surface 923.

[0033] The area of ​​the first surface 923 is, for example, 20 mm ２ It may be 30 mm or more. ２ The area of ​​the first surface 923 may be, for example, 180 mm ２ It may be less than 120 mm ２ It may be the following:

[0034] The vascular access portion 921 is formed of an elastomer. That is, the vascular access portion 921 contains an elastomer. Because the vascular access portion 921 contains an elastomer, when a needle is inserted into or removed from the vascular access portion 921, the hole made by the needle can be closed. A thermoplastic elastomer is preferable as the elastomer. When the vascular access portion 921 contains a thermoplastic elastomer, the vascular access portion 921 is easily manufactured. Examples of thermoplastic elastomers include styrene-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, olefin-based thermoplastic elastomers, polyester-based thermoplastic elastomers, and polyurethane-based thermoplastic elastomers. Among these, styrene-based thermoplastic elastomers are preferable. Examples of styrene-based thermoplastic elastomers include styrene-diene-styrene block copolymers such as styrene-butadiene-styrene block copolymer (SBS) and styrene-isoprene-styrene block copolymer (SIS). Examples of styrene-based thermoplastic elastomers include hydrogenated styrene-diene-styrene block copolymers. The vascular access portion 921 may further contain components other than the elastomer (for example, additives).

[0035] The tensile modulus of the vascular access portion 921 is preferably 250 kPa or more, and more preferably 300 kPa or more. If the modulus is 250 kPa or more, when a needle is inserted into or removed from the vascular access portion 921, the hole made by the needle can be effectively closed. In other words, the hemostatic properties are excellent. On the other hand, the tensile modulus of the vascular access portion 921 may be, for example, 1500 kPa or less, or 1000 kPa or less.

[0036] 1.1.2. Peripheral Portion The peripheral portion 926 covers the entire surface (hereinafter sometimes referred to as the "side surface") connecting the first surface 923 and the second surface 924 of the vascular access portion 921. In other words, the peripheral portion 926 covers all of the side surfaces of the vascular access portion 921. In these figures, the peripheral portion 926 covers all surfaces (i.e., surfaces) of the vascular access portion 921 except for the first surface 923 and the second surface 924. Although a tubular peripheral portion 926 is shown in these figures, the peripheral portion 926 may have a shape such as a rectangular cylinder. When the vascular access portion 921 has a rectangular columnar shape, the peripheral portion 926 preferably has a rectangular cylinder shape. In other words, the peripheral portion 926 can have a cylindrical shape (e.g., a tubular or rectangular cylinder shape).

[0037] The peripheral portion 926 includes an inner surface facing the vascular access portion 921 and an outer surface opposite the inner surface. That is, the peripheral portion 926 includes an outer surface and an inner surface that is located closer to the vascular access portion 921 than the outer surface.

[0038] The thickness of the peripheral portion 926, i.e., the thickness from the inner surface to the outer surface, may be, for example, 0.5 mm or more, or 1 mm or more. The thickness of the peripheral portion 926 may be 3 mm or less, or 2 mm or less.

[0039] The porosity of the peripheral portion 926 is preferably 50% or less, and more preferably 40% or less. The porosity of the peripheral portion 926 may be 30% or less, 20% or less, 10% or less, or 5% or less.

[0040] 1.1.2.1. Porous Tube The surrounding portion 926 includes a porous body (hereinafter, sometimes referred to as a "porous tube") having a cylindrical shape (e.g., tubular, rectangular, etc.). Specifically, the surrounding portion 926 includes a porous tube with communicating holes. Because the surrounding portion 926 includes a porous tube with communicating holes, cells can enter the communicating holes. In other words, biological tissue can infiltrate into the communicating holes. This allows the access port 92 to heal with the epidermis, reducing or preventing the progression of downgrowth (i.e., the sagging of the epidermis along the access port 92). The porous tube and the vascular access portion 921 can be joined together. For example, the porous tube and the vascular access portion 921 may be joined together by stitching, bonding with an adhesive, welding with a solvent, or heat welding.

[0041] The porous tube covers all of the sides of the vascular access portion 921. In these figures, the porous tube covers all sides (i.e., surfaces) of the vascular access portion 921 except for the first surface 923 and the second surface 924.

[0042] The porous tube includes an inner surface facing the vascular access portion 921 and an outer surface opposite the inner surface. That is, the porous tube includes an outer surface and an inner surface that is located closer to the vascular access portion 921 than the outer surface. The porous tube may have a single-layer structure or a multi-layer structure.

[0043] The thickness of the porous cylinder, i.e., the thickness from the inner surface to the outer surface, is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more of the 100% thickness of the peripheral portion 926. The thickness of the porous cylinder may be 100%.

[0044] The porous cylinder has communicating holes, i.e., interconnected pores. The porous cylinder preferably has interconnected pores extending from the inner lumen surface of the porous cylinder to the outer surface of the porous cylinder.

[0045] The porosity of the porous cylinder itself is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. This is because the higher the porosity, the closer the tensile modulus of the porous cylinder tends to be to the Young's modulus of the skin on the palmar side of the forearm or the Young's modulus of the skin on the back side of the forearm. On the other hand, the porosity of the porous cylinder itself may be, for example, 70% or less, 65% or less, or 60% or less.

[0046] It is preferable that the porous cylinder has at least one peak (hereinafter sometimes referred to as "L peak") with a peak apex in the pore diameter range of more than 100 μm to 1000 μm in the log differential pore volume distribution curve, and at least one peak (hereinafter sometimes referred to as "S peak") with a peak apex in the pore diameter range of 100 μm or less. When the porous cylinder has an L peak, i.e., has relatively large pores, biological tissue can more easily penetrate the porous cylinder. When the porous cylinder has an S peak, i.e., has small pores, when biological tissue enters the small pores, it is possible to increase the frequency of contact of the biological tissue with the artificial blood vessel, which may result in promoting tissue fixation.

[0047] The L peak may have a peak apex in the pore diameter range of 105 μm or more and 1000 μm or less, or may have a peak apex in the pore diameter range of 120 μm or more and 1000 μm or less.

[0048] The log differential pore volume of the L peak is preferably 3.0 mL / g or more, more preferably 4.0 mL / g or more, while the log differential pore volume of the L peak may be, for example, 8.0 mL / g or less, or 7.0 mL / g or less.

[0049] The S peak may have a peak apex in a pore diameter range of 60 μm or less, or may have a peak apex in a pore diameter range of 40 μm or less.

[0050] The log differential pore volume of the S peak is preferably 1.0 mL / g or more, while the log differential pore volume of the S peak may be, for example, 6.0 mL / g or less, or 5.0 mL / g or less.

[0051] The pore size distribution can be measured by mercury intrusion porosimetry. Specifically, the measurement can be performed using a pore size distribution measuring device, Autopore V9620, manufactured by Micromeritics, Inc., at an initial pressure of 1.5 kPa.

[0052] The tensile modulus of the porous tube is preferably 40 kPa or more and 190 kPa or less. When the modulus is 40 kPa or more and 190 kPa or less, the progression of downgrowth can be further reduced or prevented. This will be explained below. If the degree of deformation of the peripheral portion 926 or the porous tube caused by shear that can occur at the interface between the access port 92 and the skin is excessively smaller than the degree of deformation of the skin caused by that shear, the skin will be damaged by that shear. On the other hand, when the tensile modulus of the porous tube is 40 kPa or more and 190 kPa or less, the tensile modulus of the porous tube will be less than the Young's modulus of the skin on the palmar side of the forearm, where vascular access is often formed (specifically, approximately 100±50 kPa). １） In addition, the Young's modulus of the skin on the back of the forearm where vascular access may be formed (specifically, approximately 70±25 kPa) １） This overlaps with the above. In other words, when the tensile modulus of the porous tube is 40 kPa or more and 190 kPa or less, the rigidity of the porous tube is similar to the rigidity of the skin of the arm. Therefore, the degree of deformation of the surrounding portion 926 or the porous tube caused by shear that may occur at the interface between the access port 92 and the skin is similar to the degree of deformation of the skin that may be caused by that shear. Therefore, damage to the skin caused by that shear (i.e., shear that may occur at the interface between the access port 92 and the skin) can be reduced. Therefore, the progression of downgrowth can be further reduced or prevented.

[0053] The porous cylinder is formed of an elastomer. That is, the porous cylinder contains an elastomer. A thermoplastic elastomer is preferable as the elastomer. When the porous cylinder contains a thermoplastic elastomer, the porous cylinder is easily manufactured. Examples of thermoplastic elastomers include styrene-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, olefin-based thermoplastic elastomers, polyester-based thermoplastic elastomers, and polyurethane-based thermoplastic elastomers. Among these, polyurethane-based thermoplastic elastomers, i.e., thermoplastic polyurethane elastomers, are preferable. Examples of polyurethane-based thermoplastic elastomers include Pellethane (registered trademark), ChronoFlex (registered trademark), ChronoThane (registered trademark), and HydroThane (registered trademark). These are preferable because medical-grade products are commercially available. The porous cylinder may further contain components other than the elastomer (for example, additives).

[0054] The elastomer preferably has entropy elasticity at least between 30°C and 42°C.

[0055] The content of the elastomer in the porous cylinder is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 98% by mass or more. The content of the elastomer in the porous cylinder may be 100% by mass.

[0056] The description of the method for manufacturing the porous cylinder will be omitted here because it overlaps with the description of the porous body (i.e., porous pipe) in the artificial blood vessel 91 described later. Therefore, the description of the porous pipe in the artificial blood vessel 91 can also be used as a description of the porous cylinder in the peripheral portion 926.

[0057] 1.1.2.2. Biodegradable Material The surrounding portion 926 preferably further contains a biodegradable material with cell adhesive properties within the pores of the porous tube, specifically the interconnected pores. When the surrounding portion 926 contains a biodegradable material with cell adhesive properties within the interconnected pores of the porous tube, it can effectively bond with the epidermis, thereby further reducing or preventing the progression of downgrowth. This will be explained below. Because the surrounding portion 926 of the access port 92 contains a biodegradable material with cell adhesive properties, cells can adhere to the biodegradable material. Furthermore, because the biodegradable material is present within the interconnected pores, the number of interconnected pores into which cells can enter (i.e., empty interconnected pores) increases as the biodegradable material decomposes in the body. As a result, cells can penetrate the interconnected pores via the biodegradable material. In other words, the biodegradable material can facilitate the infiltration of biological tissue into the interconnected pores. Therefore, if the access port 92 contains a biodegradable material with cell adhesive properties within the communicating holes of the porous cylinder, it can effectively bond with the epidermis, further reducing or preventing the progression of downgrowth.

[0058] Examples of biodegradable materials include cross-linked gelatin gel and collagen. Among these, cross-linked gelatin gel is preferred because the dissolution rate in body fluids can be easily controlled by the degree of cross-linking. Note that cross-linked gelatin gel refers to cross-linked gelatin that forms a gel at 40°C.

[0059] The insoluble content of the biodegradable material is preferably 40% or more. The insoluble content may be, for example, 45% or more, or 50% or more. On the other hand, the insoluble content may be, for example, 70% or less, or 60% or less. Here, the insoluble content refers to the content that is insoluble in water.

[0060] 1.2. Artificial Blood Vessel The artificial blood vessel 91 has an inner lumen surface (hereinafter sometimes referred to as the "inner surface") and an outer surface. The artificial blood vessel 91 may be, for example, a straight type, a tapered type, or a short taper type. Of these, the straight type is preferable. Here, the straight type means a shape in which the inner diameter is constant throughout the entire artificial blood vessel 91. Both ends of the artificial blood vessel 91 are open.

[0061] The inner diameter of the artificial blood vessel 91 is preferably 4 mm to 6 mm, more preferably 5 mm to 6 mm. When the artificial blood vessel 91 is, for example, a tapered or short taper type, the inner diameter in this specification means the maximum inner diameter.

[0062] The thickness of the artificial blood vessel 91 is preferably 0.5 mm or more, more preferably 1.0 mm or more, while the thickness of the artificial blood vessel 91 is preferably 2.0 mm or less, more preferably 1.5 mm or less.

[0063] The length of the artificial blood vessel 91 may be, for example, 50 mm or more, 100 mm or more, 200 mm or more, or 300 mm or more. The length of the artificial blood vessel 91 may be 600 mm or less, or 500 mm or less. Note that the artificial blood vessel 91 may be cut as necessary to adjust its length before placement, and in this paragraph, the length of the artificial blood vessel 91 refers to the length before cutting.

[0064] The artificial blood vessel 91 includes a tubular porous body (i.e., a porous tube) and a biodegradable material in the pores of the porous tube, specifically in the communicating pores. Because the artificial blood vessel 91 includes a biodegradable material in the communicating pores of the porous tube, the number of vacant communicating pores increases as the biodegradable material decomposes in the body. Therefore, as the decomposition of the biodegradable material progresses, tissues, capillaries, cells, etc. can penetrate into the communicating pores.

[0065] <1.2.1. Porous Tube> <1.2.1.1. Structure, Properties, etc. of Porous Tube> The artificial blood vessel 91 includes a porous tube. The porous tube has an inner lumen surface (hereinafter sometimes referred to as the "inner surface") and an outer surface. Both ends of the porous tube (i.e., the first end and the second end) are open. The porous tube may have a single-layer structure or a multi-layer structure.

[0066] The description of the inner diameter of the porous tube will be omitted because it overlaps with the description of the inner diameter of the artificial blood vessel. Therefore, the description of the inner diameter of the artificial blood vessel can also be used as the description of the inner diameter of the porous tube. However, the inner diameter of the porous tube and the inner diameter of the artificial blood vessel do not have to be the same. In other words, the inner diameter of the porous tube and the inner diameter of the artificial blood vessel may be the same or different. For example, the inner diameter of the porous tube may be larger than the inner diameter of the artificial blood vessel.

[0067] The description of the thickness of the porous tube will be omitted because it overlaps with the description of the thickness of the artificial blood vessel. Therefore, the description of the thickness of the artificial blood vessel can also be used as the description of the thickness of the porous tube. However, the thickness of the porous tube and the thickness of the artificial blood vessel do not have to be the same. In other words, the thickness of the porous tube and the thickness of the artificial blood vessel may be the same or different. For example, the thickness of the porous tube may be smaller than the thickness of the artificial blood vessel.

[0068] The explanation of the length of the porous tube is omitted here because it overlaps with the explanation of the length of the artificial blood vessel. Therefore, the explanation of the length of the artificial blood vessel can also be used as the explanation of the length of the porous tube.

[0069] A porous tube has interconnected pores. Specifically, the porous tube has interconnected pores extending from the inner surface of the porous tube to the outer surface of the porous tube. This allows tissues, capillaries, cells, and the like to invade the porous tube. This promotes their infiltration, which in turn promotes intimal formation.

[0070] The porous pipe preferably contains a thermoplastic elastomer. When the porous pipe contains a thermoplastic elastomer, the porous pipe is easy to manufacture. The porous pipe may further contain components other than the thermoplastic elastomer (for example, additives).

[0071] An example of a thermoplastic elastomer is a thermoplastic polyurethane elastomer. When a porous tube contains a thermoplastic polyurethane elastomer, the porous tube is easy to manufacture. Moreover, in this case, it is possible to impart entropy elasticity to the porous tube, thereby providing an artificial blood vessel that is easy to place.

[0072] Examples of thermoplastic polyurethane elastomers include Pellethane®, ChronoFlex®, ChronoThane®, and HydroThane®, which are preferred because medical grades are commercially available.

[0073] The thermoplastic elastomer preferably has entropy elasticity at least at 30° C. to 42° C. When the porous tube has entropy elasticity, an artificial blood vessel that can be easily placed can be provided.

[0074] The content of the thermoplastic elastomer in the porous pipe is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 98% by mass or more. The content of the thermoplastic elastomer in the porous pipe may be 100% by mass.

[0075] <1.2.1.2. Method for Producing Porous Pipe> As an example of a method for producing a porous pipe, a preferred method for producing a porous body containing a thermoplastic polyurethane elastomer will be described.

[0076] The method for producing a porous pipe may include the steps of preparing a porous polyurethane stock solution containing a thermoplastic polyurethane elastomer, dimethyl sulfoxide, and a pore-forming agent that is insoluble in dimethyl sulfoxide and water-soluble (hereinafter referred to as the "preparation step"); solidifying the porous polyurethane stock solution by cooling it while it is in a tubular state (hereinafter referred to as the "solidification step"); and washing the tubular solid product of the solidified porous polyurethane stock solution with water (hereinafter referred to as the "washing step"). This production method can produce a porous pipe having pores derived from the pore-forming agent and pores derived from dimethyl sulfoxide crystals. The method for producing a porous pipe may further include the step of drying the porous pipe obtained in the washing step.

[0077] <1.2.1.2.1. Preparation Step> In this step, a stock solution of porous polyurethane is prepared. For example, the stock solution of porous polyurethane can be prepared by mixing and stirring a thermoplastic polyurethane elastomer and dimethyl sulfoxide, and then adding a pore-forming agent and stirring, or by mixing a thermoplastic polyurethane elastomer and a pore-forming agent with dimethyl sulfoxide and stirring. The former is preferred.

[0078] The temperature of dimethyl sulfoxide mixed with at least the thermoplastic polyurethane elastomer is preferably 70°C or higher. At 70°C or higher, the thermoplastic polyurethane elastomer can be easily dissolved in dimethyl sulfoxide. The temperature of dimethyl sulfoxide may be, for example, 80°C or higher, or 90°C or higher. The temperature of dimethyl sulfoxide may be, for example, 150°C or lower, or 120°C or lower.

[0079] The pore-forming agent is a particle that is insoluble in dimethyl sulfoxide and water-soluble. The particle size of the pore-forming agent can be adjusted using a mortar, a sieve, etc. An example of the pore-forming agent is sodium chloride.

[0080] The content of the thermoplastic polyurethane elastomer is preferably 3% by mass or more, more preferably 4% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of the polyurethane porous material liquid. On the other hand, the content of the thermoplastic polyurethane elastomer is preferably 7% by mass or less, more preferably 6% by mass or less, and even more preferably 5.5% by mass or less, based on 100% by mass of the polyurethane porous material liquid. The lower the content of the thermoplastic polyurethane elastomer, the higher the porosity of the porous pipe can be.

[0081] The content of the pore-forming agent is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to 100% by mass of the polyurethane porous material stock solution, while the content of the pore-forming agent is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, relative to 100% by mass of the polyurethane porous material stock solution.

[0082] The total content of the thermoplastic polyurethane elastomer, dimethyl sulfoxide, and pore-forming agent is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 100% by mass, based on 100% by mass of the polyurethane porous material stock solution.

[0083] 1.2.1.2.2. Solidification Step In this step, the porous polyurethane liquid is solidified by cooling it while it is in a tubular state. To create a tubular state of the porous polyurethane liquid, it is preferable to prepare a cylindrical rod and a mold including an inner wall capable of forming a cylindrical cavity concentric with the rod, and fill the space between the rod and the inner wall (i.e., the tubular space) with the porous polyurethane liquid.

[0084] To solidify the porous polyurethane liquid, the porous polyurethane liquid is cooled to a temperature below the freezing point of dimethyl sulfoxide, for example, 10°C or below, 0°C or below, or -10°C or below.

[0085] <1.2.1.2.3. Washing Step> In this step, the tubular solid formed by solidifying the polyurethane porous material stock solution is washed with water. Because both dimethyl sulfoxide and the pore-forming agent are soluble in water, washing the tubular solid with water can remove the dimethyl sulfoxide and pore-forming agent from the tubular solid. Therefore, a porous tube can be obtained by washing the tubular solid with water. For example, tap water, ion-exchanged water, distilled water, or ultrapure water can be used to wash the tubular solid. Note that water washing may be performed multiple times. For example, the tubular solid may be washed with water below the freezing point of dimethyl sulfoxide (e.g., ice-cold water), and then further washed with warm water at 50°C to 70°C. After washing with water, the porous tube may be dried.

[0086] <1.2.1.2.4. Other Steps> The porous tube may be cut to adjust its length.

[0087] 1.2.2. Biodegradable Material The artificial blood vessel 91 contains a biodegradable material in the pores of the porous tube, specifically in the communicating holes. A description of the biodegradable material in the artificial blood vessel 91 will be omitted because it overlaps with the description of the biodegradable material in the peripheral portion 926. Therefore, the description of the biodegradable material in the peripheral portion 926 can also be used as a description of the biodegradable material in the artificial blood vessel 91.

[0088] 1.2.3. First Reinforcing Thread The artificial blood vessel 91 may further include a first thread (hereinafter, sometimes referred to as the "first reinforcing thread") extending in a clockwise spiral from the first end to the second end of the porous tube. The first reinforcing thread can prevent or reduce kinking (i.e., a phenomenon in which the artificial blood vessel is excessively bent, causing the lumen of the artificial blood vessel to close).

[0089] The first reinforcing yarns may extend, for example, in a spiral shape on the outer surface of the porous pipe, or in a spiral shape within the porous pipe, and it is particularly preferable that the first reinforcing yarns extend in a spiral shape within the porous pipe.

[0090] The pitch of the first reinforcing yarns may be, for example, 1 mm or more, or 2 mm or more, while the pitch of the first reinforcing yarns may be, for example, 10 mm or less, or 5 mm or less.

[0091] The diameter of the first reinforcing yarns may be, for example, 100 μm or more, or 120 μm or more, while the diameter of the first reinforcing yarns may be, for example, 200 μm or less, or 180 μm or less.

[0092] Examples of the first reinforcing yarn include filament yarn and spun yarn. Examples of the filament yarn include monofilament and multifilament. Of these, monofilament is preferred. Examples of the monofilament include polyester monofilament, nylon monofilament, and polypropylene monofilament. Of these, polyester monofilament is preferred.

[0093] 1.2.4 Second Reinforcing Thread The artificial blood vessel 91 may further include a second thread (hereinafter, sometimes referred to as the "second reinforcing thread") extending counterclockwise in a spiral shape from the first end to the second end of the porous tube. The second reinforcing thread can further prevent or reduce kinking.

[0094] The description of the second reinforcing yarns will be omitted because it overlaps with the description of the first reinforcing yarns. Therefore, the description of the first reinforcing yarns can also be used as the description of the second reinforcing yarns.

[0095] <1.2.5. Others> The artificial blood vessel may further include a layer (hereinafter, sometimes referred to as a "coating layer") that covers the outer surface of the porous tube. The coating layer may contain a biodegradable material. A description of the biodegradable material of the coating layer will be omitted because it overlaps with the description of the biodegradable material in the peripheral portion 926. Therefore, the description of the biodegradable material in the peripheral portion 926 can also be used as a description of the biodegradable material of the coating layer.

[0096] On the other hand, the artificial blood vessel may further include a layer covering the inner surface of the porous tube.The artificial blood vessel may also include components other than the biodegradable material (e.g., additives) in the communicating pores of the porous tube.

[0097] 2. Placement The vascular access device 9 is placed in a manner in which at least a portion of the first surface 923 of the vascular access portion 921 is exposed from the skin 12. By placing the vascular access device 9 in this manner, pain from puncture can be avoided or reduced. Note that these figures show a manner in which the entire first surface 923 is exposed from the skin 12.

[0098] To place the vascular access device 9, an artery and a vein can be connected together using the vascular access device 9. That is, one end of the artificial blood vessel 91 of the vascular access device 9 can be anastomosed to an artery, and the other end of the artificial blood vessel 91 of the vascular access device 9 can be anastomosed to a vein. In this case, the placement procedure for the vascular access device 9 can include, for example, incising the skin 12 of a living body (e.g., the skin of a human arm), connecting the artery and the vein with the vascular access device 9, and then sewn up the vascular access device 9 so that at least a portion of the first surface 923 of the vascular access portion 921 is exposed from the skin 12. Examples of veins include the cephalic vein, basilic vein, and saphenous vein. The blood vessel (specifically, the artery or vein) and the artificial blood vessel 91 can be sewn up with sutures. In this case, the artificial blood vessel 91 of the vascular access device 9 may be placed in a loop shape or a straight shape, for example.

[0099] The length of the placed artificial blood vessel 91 may be, for example, 50 mm or more, or 100 mm or more. The length of the placed artificial blood vessel 91 may be 600 mm or less, or 500 mm or less.

[0100] 3. Manufacturing Method of Access Port The manufacturing method of the access port 92 in this embodiment includes the steps of immersing the pre-immersion access port in an aqueous solution containing a water-soluble biodegradable material with cell adhesive properties under reduced pressure (hereinafter sometimes referred to as the “immersion step”), increasing the atmospheric pressure of the aqueous solution in which the pre-immersion access port is immersed (hereinafter sometimes referred to as the “pressurization step”), removing the post-immersion access port from the aqueous solution (hereinafter sometimes referred to as the “removal step”), and insolubilizing the water-soluble biodegradable material contained in the post-immersion access port (hereinafter sometimes referred to as the “insolubilization step”). The manufacturing method of the access port 92 in this embodiment may further include the step of preparing the pre-immersion access port (hereinafter sometimes referred to as the “preparation step”) prior to the immersion step.

[0101] 3.1 Preparation Step In this step, a pre-immersion access port is prepared. The pre-immersion access port may be the same as the access port 92 of this embodiment, except that the porous cylinder does not contain a biodegradable material within the communicating holes. The pre-immersion access port includes a vascular access portion 921 and a porous cylinder surrounding the vascular access portion 921.

[0102] 3.2 Immersion Step In this step, the pre-immersion access port is immersed in an aqueous solution containing a water-soluble biodegradable material with cell adhesive properties under reduced pressure. For example, the pre-immersion access port can be immersed in (i.e., placed in) the aqueous solution in a container, and then the pre-immersion access port and the container are placed in a desiccator, and the pressure in the desiccator is reduced and maintained.

[0103] Gelatin is preferred as the water-soluble biodegradable material. The content of the water-soluble biodegradable material in the aqueous solution is preferably 5% by mass or more, more preferably 7% by mass or more. When the content is 5% by mass or more, the gel strength is high. On the other hand, the content of the water-soluble biodegradable material in the aqueous solution is preferably 15% by mass or less, more preferably 12% by mass or less. When the content is 15% by mass or less, the viscosity of the aqueous solution is low, making it easier to fill the porous cylinder.

[0104] The reduced pressure environment is an environment below atmospheric pressure, preferably an environment of 25 kPa or less, more preferably an environment of 20 kPa or less, and even more preferably an environment of 15 kPa or less, which allows the water-soluble biodegradable material to effectively penetrate into the communicating pores of the porous cylinder.

[0105] While the access port is immersed in the aqueous solution under reduced pressure before immersion, the temperature of the aqueous solution is preferably 35° C. or higher, and more preferably 40° C. or higher, so that the water-soluble biodegradable material can effectively penetrate into the communicating pores of the porous cylinder.

[0106] The time for which the access port is immersed in the aqueous solution under reduced pressure before immersion, i.e., the immersion time under reduced pressure, is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more.

[0107] <3.3. Pressurization Step> In this step, the atmospheric pressure of the aqueous solution in which the pre-immersion access port is immersed is increased. In this step, the atmospheric pressure is preferably increased to atmospheric pressure or higher, and more preferably increased to atmospheric pressure.

[0108] 3.4. Removal Step In this step, the post-immersion access port is removed from the aqueous solution, and the aqueous solution adhering to the surface of the porous cylinder of the post-immersion access port is removed, if necessary.

[0109] <3.5. Insolubilization Step> In this step, the water-soluble biodegradable material contained in the access port after immersion is insolubilized. For insolubilization, the access port after immersion is preferably irradiated with an electron beam. When the water-soluble biodegradable material is gelatin, this allows the gelatin to be crosslinked without using a crosslinking agent that may affect the body. When crosslinking gelatin with an electron beam, the dose of the electron beam is preferably 20 kGy or more, more preferably 25 kGy or more. At 20 kGy or more, the gelatin aqueous solution can be effectively gelled and the insoluble content can be increased. On the other hand, the dose of the electron beam may be, for example, 80 kGy or less, 60 kGy or less, 50 kGy or less, or 45 kGy or less. Among these, 45 kGy or less is preferred from the viewpoint of preventing excessive yellowing of the porous tube.

[0110] 4. Various modifications can be made to the above-described embodiment. Various modifications can be made to the above-described embodiment. For example, one or more of the following modifications can be selected and made to the above-described embodiment.

[0111] In the above-described embodiment, a configuration in which an artery and a vein are connected by the vascular access device 9 has been described. However, the present invention is not limited to this configuration. For example, veins may be connected by the vascular access device 9. In this case, the placement procedure of the vascular access device 9 may include, for example, incising the skin 12 of a living body (e.g., the skin of a human arm), connecting the veins with the artificial blood vessel 91 of the vascular access device 9, and then suturing the vascular access device 9 so that at least a portion of the first surface 923 of the vascular access portion 921 is exposed from the skin 12. When the living body has an internal shunt, it is preferable to connect the veins with the vascular access device 9 downstream of the anastomosis (e.g., the anastomosis between an artery and a vein in an autologous intravascular shunt, the anastomosis between an artificial blood vessel and a vein in an artificial intravascular shunt, etc.).

[0112] In the above-described embodiment, a configuration has been described in which the access port 92 extends laterally from the outer surface of the artificial blood vessel 91. In this configuration, the second surface 924 of the access port 92 is not exposed toward the lumen of the artificial blood vessel 91. However, the vascular access device 9 is not limited to this configuration. As shown in FIG. 1D , at least the second surface 924 of the access port 92 may be exposed toward the lumen of the artificial blood vessel 91. In this case, at least the second surface 924 of the access port 92 may be exposed toward the lumen of the artificial blood vessel 91 from an opening formed in the artificial blood vessel 91. In this manner, with at least the second surface 924 of the access port 92 exposed toward the lumen of the artificial blood vessel 91, the second surface 924 may face the artificial blood vessel 91.

[0113] In the above-described embodiment, the peripheral portion 926 covers the entire side surface of the vascular access portion 921. However, the vascular access device 9 is not limited to this configuration. As shown in Fig. 1E, the peripheral portion 926 may cover only a portion of the side surface of the vascular access portion 921. In this figure, the side surface near the tip of the vascular access portion 921 is exposed.

[0114] In the above-described embodiment, a configuration in which a porous tube is bonded to the vascular access portion 921 has been described. However, the vascular access device 9 is not limited to this configuration. For example, as shown in FIG. 1F , the peripheral portion 926 of the vascular access device 9 may include a non-porous thermoplastic elastomer layer 62 and a porous tube 61 bonded to the thermoplastic elastomer layer 62. In other words, the porous tube 61 may be bonded to the thermoplastic elastomer layer 62. In the vascular access device 9 shown in this figure, the thermoplastic elastomer layer 62 is provided between the porous tube 61 and the vascular access portion 921.

[0115] In the above-described embodiment, the access port 92 extends in a columnar shape laterally from the artificial blood vessel 91. However, the vascular access device 9 is not limited to this configuration. The shape of the access port 92 can be modified as appropriate. This will be described below. The access port 92 may have a shape such as that shown in FIGS. 2A, 2B, and 2C. That is, the access port 92 may extend along the length of the artificial blood vessel 91 while increasing in height without separating from the artificial blood vessel 91. The access port 92 may have a shape such as that shown in FIGS. 3A, 3B, and 3C. That is, the access port 92 may extend along the length of the artificial blood vessel 91 at a constant height H without separating from the artificial blood vessel 91. The length L of the access port 92 in this example is as described in the above-described embodiment, but may also be, for example, 10 mm or more, or 25 mm or more. The length L of the access port 92 may be 200 mm or less, or 150 mm or less. In these figures (i.e., FIGS. 2A, 2B, 2C, 3A, 3B, and 3C), the width W of the access port 92 is generally constant along the height H of the access port 92. However, the width W of the access port 92 is not limited to this. For example, as shown in FIG. 3D, the width W of the access port 92 may increase along the height H of the access port 92. This allows the area of ​​the first surface 923 to be increased compared to when the width W of the access port 92 is constant along the height H of the access port 92.

[0116] In the above embodiment, a configuration has been described in which the artificial blood vessel 91 and the access port 92 are joined together. Accordingly, it could be said that a configuration has been described in which the porous tube of the peripheral portion 926 of the access port 92 is fabricated separately from the porous tube of the artificial blood vessel 91. However, the vascular access device 9 is not limited to this configuration. When fabricating the vascular access device 9, a porous member including a porous tube and a porous tube protruding from the porous tube may be fabricated. In other words, the porous tube of the peripheral portion 926 of the access port 92 may be fabricated together with the porous tube of the artificial blood vessel 91.

[0117] In the above embodiment, the access port 92 is used in a living body together with the artificial blood vessel 91. However, the access port 92 may be used in a living body independently of the artificial blood vessel 91. In other words, the access port 92 may be used in a living body without the artificial blood vessel 91.

[0118] In the above-described embodiment, the porous tube is made of an elastomer. However, the vascular access device 9 is not limited to this configuration. The porous tube may be made of a material other than an elastomer.

[0119] In the above-described embodiment, the access port 92 is manufactured by a method that includes a step of immersing the access port in the aqueous solution and then removing it (i.e., a removal step) between the pressurizing step and the insolubilizing step. However, this embodiment is not limited to this configuration. For example, the removal step may be omitted.

[0120] In the above embodiment, the artificial blood vessel 91 includes a porous tube and a biodegradable material in the pores of the porous tube. However, the present embodiment is not limited to this configuration.

[0121] 5. Catheter The catheter of this embodiment is a catheter that is placed in a living body with at least a portion thereof exposed from the skin. Hereinafter, a catheter for continuous ambulatory peritoneal dialysis (CAPD) and a central venous catheter will be described.

[0122] 5.1 Continuous Ambulatory Peritoneal Dialysis (CAPD) Catheter As shown in FIG. 4A , the CAPD catheter 7 in this embodiment includes a tube 71 and cuffs 72a, 72b attached to the tube 71. The tube 71 and the cuffs 72a, 72b can be attached by any method. For example, they may be sewn together, bonded with an adhesive, welded with a solvent, or welded with heat. Note that the catheter 7 may include components other than the tube 71 and the cuffs 72a, 72b. The catheter 7 may also include additional cuffs.

[0123] One end of the catheter 7 is inserted into the abdominal cavity. Therefore, the catheter 7 is left in the living body with a portion of the tube 71 exposed from the skin. Typically, one of the cuffs 72 a, 72 b is fixed to the rectus abdominis muscle, and the other is placed in the subcutaneous tissue with a portion exposed from the skin.

[0124] The tube 71 is preferably made of an elastomer, i.e., the tube 71 preferably contains an elastomer, such as a silicone elastomer.

[0125] The cuffs 72a, 72b extend along the circumferential direction of the tube 71. Therefore, the cuffs 72a, 72b are cylindrical (e.g., tubular, rectangular, etc.) The cuffs 72a, 72b include an inner surface located closer to the tube 71 and an outer surface opposite the inner surface.

[0126] The cuffs 72a, 72b comprise a porous body (hereinafter sometimes referred to as a "porous tube") having a cylindrical shape (e.g., a tubular or rectangular shape). Specifically, the cuffs 72a, 72b comprise porous tubes with communicating holes. Because the cuffs 72a, 72b comprise porous tubes with communicating holes, cells can enter the communicating holes. In other words, biological tissue can infiltrate into the communicating holes. Therefore, by placing the catheter 7 in a state in which at least one of the cuffs 72a, 72b is partially exposed from the skin, it is possible for the cuffs to heal with the epidermis, and therefore the progression of downgrowth (i.e., the sagging of the epidermis along the catheter 7) can be reduced or prevented.

[0127] The description of the porous cylinders in the cuffs 72a and 72b will be omitted because it overlaps with the description of the porous cylinder in the access port 92. Therefore, the description of the porous cylinder in the access port 92 can also be used as a description of the porous cylinders in the cuffs 72a and 72b.

[0128] Although the description of the porous tube in the access port 92 overlaps, the tensile modulus of the porous tube in the cuffs 72a, 72b will be explained here for clarity and emphasis. The tensile modulus of the porous tube in the cuffs 72a, 72b is preferably 40 kPa or more and 190 kPa or less. A tensile modulus of 40 kPa or more and 190 kPa or less can further reduce or prevent the progression of downgrowth. This is explained below. If the degree of deformation of the cuffs 72a, 72b or the porous tube caused by shear that can occur at the interface between the cuffs 72a, 72b and the skin is excessively smaller than the degree of deformation of the skin caused by that shear, the skin will be damaged by that shear. On the other hand, if the tensile modulus of the porous tube is 40 kPa or more and 190 kPa or less, the tensile modulus of the porous tube will overlap or be close to the Young's modulus of the skin surrounding the cuffs 72a, 72b. Therefore, the rigidity of the porous tube is similar to the rigidity of the skin surrounding the cuffs 72a, 72b. Therefore, the degree of deformation of the cuffs 72a, 72b or the porous tube caused by shear that may occur at the interface between the cuffs 72a, 72b and the skin is similar to the degree of deformation of the skin that may be caused by that shear. Therefore, when the catheter 7 is placed in a manner such that at least one of the cuffs 72a, 72b is partially exposed from the skin, damage to the skin caused by that shear (i.e., shear that may occur at the interface between the skin and at least one of the cuffs 72a, 72b placed in a manner such that it is partially exposed from the skin) can be reduced. Therefore, the progression of downgrowth can be further reduced or prevented.

[0129] Preferably, the cuffs 72a, 72b further contain a biodegradable material with cell adhesive properties within the pores of the porous tube, specifically the interconnecting pores. When the cuffs 72a, 72b contain a biodegradable material with cell adhesive properties within the interconnecting pores of the porous tube, they can effectively adhere to the epidermis, thereby further reducing or preventing the progression of downgrowth. This is explained below. Because the cuffs 72a, 72b contain a biodegradable material with cell adhesive properties, cells can adhere to the biodegradable material. Furthermore, because the biodegradable material is present within the interconnecting pores, the number of interconnecting pores into which cells can enter (i.e., empty interconnecting pores) increases as the biodegradable material decomposes in the body. As a result, cells can penetrate the interconnecting pores via the biodegradable material. In other words, the biodegradable material can facilitate the infiltration of biological tissue into the interconnecting pores. Therefore, when the catheter 7 contains a biodegradable material with cell adhesive properties within the interconnecting pores of the porous tube, it can effectively adhere to the epidermis. Therefore, when the catheter 7 is placed in a manner such that at least one of the cuffs 72a, 72b is partially exposed from the skin, the progression of downgrowth can be further reduced or prevented.

[0130] A description of the biodegradable material in the cuffs 72a, 72b will be omitted because it overlaps with the description of the biodegradable material in the access port 92. Therefore, the description of the biodegradable material in the access port 92 can also be used as a description of the biodegradable material in the cuffs 72a, 72b.

[0131] In the above embodiment, the cuffs 72a and 72b are cylindrical, but the catheter 7 is not limited to this configuration.

[0132] In the above embodiment, the configuration in which both the cuffs 72 a and 72 b include a porous tube has been described. However, the catheter 7 is not limited to this configuration. Only one of the cuffs 72 a and 72 b may include a porous tube.

[0133] 5.2. Central Venous Catheter As shown in FIG. 4B , the central venous catheter 8 in this embodiment is a cuff-type catheter, specifically a double-lumen catheter. The catheter 8 is placed in a living body with the bifurcation 85, branch vessels 86a, and branch vessels 86b located outside the living body. The cuff 82 of the catheter 8 is placed in a living body with the cuff 82 partially exposed from the skin. The catheter 8 can be placed so that its tip is located in the right atrium. In this case, the catheter 8 can be inserted from the internal jugular vein toward the right atrium. Alternatively, the catheter 8 can be placed so that its tip is located in the inferior vena cava. In this case, the catheter 8 can be inserted from the femoral vein toward the inferior vena cava.

[0134] The catheter 8 includes a tube 81. The tube 81 includes a tubular outer wall extending in the longitudinal direction and a partition (not shown) extending in the longitudinal direction through a cavity in the tubular outer wall. The cavity of the tube 81 is divided into a first lumen and a second lumen by the partition. That is, the tube 81 includes a partition that divides the tubular cavity of the tube 81 into the first lumen and the second lumen. The first lumen may open at or near the tip of the tube 81, specifically, the tip for insertion into a blood vessel. The second lumen may open at or near the tip of the tube 81, specifically, the tip for insertion into a blood vessel. The tube 81 is preferably formed of an elastomer. That is, the tube 81 preferably contains an elastomer. An example of the elastomer is a polyurethane-based thermoplastic elastomer. The tube 81 may further include an additive. An example of the additive is a contrast agent. Contrast agents include, for example, barium sulfate, bismuth tungstate, and bismuth oxide.

[0135] The catheter 8 further includes a branch tube (hereinafter sometimes referred to as "tube") 86a, a branch tube (hereinafter sometimes referred to as "tube") 86b, and a bifurcation portion 85. The bifurcation portion 85 connects the branch tube 86a to the tube 81 and also connects the branch tube 86b to the tube 81. The bifurcation portion 85 includes a first cavity for connecting the cavity of the branch tube 86a to the first lumen. The bifurcation portion 85 includes a second cavity for connecting the cavity of the branch tube 86b to the second lumen. The bifurcation portion 85 is preferably formed of an elastomer. That is, the bifurcation portion 85 preferably contains an elastomer. An example of the elastomer is a polyurethane-based thermoplastic elastomer. The bifurcation portion 85 may further contain an additive. The branch tube 86a, i.e., the tube 86a, is preferably formed of an elastomer. That is, the branch tube 86a preferably contains an elastomer. An example of the elastomer is a polyurethane-based thermoplastic elastomer. The branch tube 86a may further contain an additive. The branch pipe 86b, i.e., the tube 86b, is preferably formed of an elastomer. That is, the branch pipe 86b preferably contains an elastomer. An example of the elastomer is a polyurethane-based thermoplastic elastomer. The branch pipe 86b may further contain an additive.

[0136] The catheter 8 further includes a connector 87a provided on the branch tube 86a and a connector 87b provided on the branch tube 86b. Because the catheter 8 includes the connector 87a, the branch tube 86a can be connected to an external device, such as a dialysis circuit, at least via the connector 87a. On the other hand, because the catheter 8 includes the connector 87b, the branch tube 86b can be connected to an external device, such as a dialysis circuit, at least via the connector 87b. The connector 87a is preferably formed from a resin. That is, the connector 87a preferably contains a resin. Examples of the resin include polyacetal and polycarbonate. The connector 87a may further contain an additive. The connector 87b is preferably formed from a resin. That is, the connector 87b preferably contains a resin. Examples of the resin include polyacetal and polycarbonate. The connector 87b may further contain an additive.

[0137] The catheter 8 further includes a clamp 88a provided on the branch tube 86a and a clamp 88b provided on the branch tube 86b. Because the catheter 8 includes the clamp 88a, the branch tube 86a can be closed as needed. Because the catheter 8 includes the clamp 88b, the branch tube 86b can be closed as needed. The clamp 88a can be located closer to the bifurcation 85 than the connector 87a. The clamp 88b can be located closer to the bifurcation 85 than the connector 87b.

[0138] The catheter 8 includes a cuff 82 attached to a tube 81. The tube 81 and the cuff 82 can be attached in any manner, for example, by stitching, adhesive bonding, solvent welding, or heat welding. The catheter 8 may include additional cuffs.

[0139] The cuff 82 extends along the circumferential direction of the tube 81. Therefore, the cuff 82 has a cylindrical shape (e.g., a tubular shape, a rectangular cylindrical shape, etc.). The cuff 82 includes an inner surface located closer to the tube 81 and an outer surface opposite the inner surface.

[0140] The cuff 82 includes a porous body (hereinafter sometimes referred to as a "porous tube") having a cylindrical shape (e.g., tubular, rectangular, etc.). Specifically, the cuff 82 includes a porous tube with communicating holes. Because the cuff 82 includes a porous tube with communicating holes, cells can enter the communicating holes. In other words, biological tissue can infiltrate into the communicating holes. Therefore, by placing the catheter 7 in a manner such that the cuff 82 is partially exposed from the skin, it is possible for the cuff 82 to heal with the epidermis, and therefore the progression of downgrowth (i.e., the sagging of the epidermis along the catheter 8) can be reduced or prevented.

[0141] The description of the porous cylinder in the cuff 82 will be omitted because it overlaps with the description of the porous cylinder in the access port 92. Therefore, the description of the porous cylinder in the access port 92 can also be used as a description of the porous cylinder in the cuff 82.

[0142] Although the explanation of the porous tube in the access port 92 overlaps, the tensile modulus of the porous tube in the cuff 82 will be explained here for clarity and emphasis. The tensile modulus of the porous tube in the cuff 82 is preferably 40 kPa or more and 190 kPa or less. A tensile modulus of 40 kPa or more and 190 kPa or less can further reduce or prevent the progression of downgrowth. This is explained below. If the degree of deformation of the cuff 82 or the porous tube caused by shear that can occur at the interface between the cuff 82 and the skin is excessively smaller than the degree of deformation of the skin caused by that shear, the skin will be damaged by that shear. On the other hand, if the tensile modulus of the porous tube is 40 kPa or more and 190 kPa or less, the tensile modulus of the porous tube overlaps or is close to the Young's modulus of the skin surrounding the cuff 82. Therefore, the stiffness of the porous tube is similar to the stiffness of the skin surrounding the cuff 82. Therefore, the degree of deformation of the cuff 82 or the porous tube caused by shear that may occur at the interface between the cuff 82 and the skin is similar to the degree of deformation of the skin that may occur due to that shear. Therefore, when the catheter 7 is placed in a manner that leaves the cuff 82 partially exposed from the skin, damage to the skin caused by that shear (i.e., shear that may occur at the interface between the cuff 82 and the skin) can be reduced. This further reduces or prevents the progression of downgrowth.

[0143] Preferably, the cuff 82 further contains a biodegradable material with cell adhesive properties within the pores of the porous tube, specifically the interconnected pores. When the cuff 82 contains a biodegradable material with cell adhesive properties within the interconnected pores of the porous tube, it can effectively adhere to the epidermis, thereby further reducing or preventing the progression of downgrowth. This is explained below. Because the cuff 82 contains a biodegradable material with cell adhesive properties, cells can adhere to the biodegradable material. Furthermore, because the biodegradable material is present within the interconnected pores, the number of interconnected pores into which cells can enter (i.e., empty interconnected pores) increases as the biodegradable material decomposes in the body. As a result, cells can enter the interconnected pores via the biodegradable material. In other words, the biodegradable material can facilitate the infiltration of biological tissue into the interconnected pores. Therefore, when the catheter 8 contains a biodegradable material with cell adhesive properties within the interconnected pores of the porous tube, it can effectively adhere to the epidermis. Therefore, when the catheter 7 is placed in a manner such that the cuff 82 is partially exposed from the skin, the progression of downgrowth can be further reduced or prevented.

[0144] The description of the biodegradable material in the cuff 82 will be omitted because it overlaps with the description of the biodegradable material in the access port 92. Therefore, the description of the biodegradable material in the access port 92 can also be used as a description of the biodegradable material in the cuff 82.

[0145] The catheter 8 may be treated to immobilize uroginase.

[0146] In the above-described embodiment, the catheter 8 is a double-lumen catheter. However, the catheter 8 is not limited to this configuration. The catheter 8 may be, for example, a single-lumen catheter or a triple-lumen catheter.

[0147] In the above embodiment, the cuff 89 is cylindrical. However, the catheter 8 is not limited to this configuration.

[0148] The present invention will be described in more detail below with reference to examples and comparative examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0149] <1. Evaluation Method> <1.1. Measurement of Porosity> A 5 ​​cm square membrane sample having the same thickness as the flat membrane was cut out from the flat membrane of the polyurethane porous body, and the mass (Wp) of the membrane sample was measured. The thickness (T) of the membrane sample was measured using the following procedure. First, the flat membrane was cut with a 76 razor. Next, the cross section was observed with a scanning electron microscope. Then, the thickness was measured at three points from the observed cross-sectional image. Since the thickness of the flat membrane was the same as that of the membrane sample, the average value was calculated as the thickness (T) of the membrane sample. Assuming that the density of polyurethane was 1.05 g / mL, the porosity was calculated using the following formula: Porosity (%) = {1 - (W ｐ / W ｎｐ )×100 In this formula, W ｐ , i.e., the mass of the film sample is substituted with a value in g. In this formula, W ｎｐ is calculated using the following formula: ｎｐ = (5 x 5 x T) x 1.05 Here, a value in cm is substituted for T, ie, the thickness of the film sample.

[0150] <1.2. Measurement of pore size distribution> The pore size distribution was measured by mercury intrusion porosimetry at the request of Shimadzu Techno Research Corporation. The measurement device used was a pore distribution measurement device Autopore V9620 manufactured by Micromeritics. The pore size distribution was measured at an initial pressure of 1.5 kPa.

[0151] <1.3. Measurement of tensile modulus> A test piece measuring 50 mm in length and 5 mm in width was prepared. For example, a test piece measuring 50 mm in length and 5 mm in width was cut out from the flat membrane of the polyurethane porous material produced in Production Example 1. A tensile test was carried out using an Autograph AGS-X 1 kN manufactured by Shimadzu Corporation, with a gauge length of 30 mm and a tensile speed of 150 mm / min. The tensile modulus was calculated using the cross-sectional area (A) of the test piece and the elongation strain, i.e., the load (f1) when the tensile strain was 1% and the load (f5) when the elongation strain was 5%, according to the following formula: A (m２ ) = 5 / 1000 × T (cm) / 100 Tensile modulus (kPa) = (f5 (N) - f1 (N)) / A (m ２ ) / (0.04)

[0152] <1.4. Measurement of Porosity> <1.4.1. Gelatin-Impregnated Access Port> <1.4.1.1. SEM> A 76 razor (specifically, a 76 razor manufactured by Nissin EM Co., Ltd.) was pressed against the gelatin-impregnated access port (see Example 1) along the radial direction of the gelatin-impregnated access port, and then the gelatin-impregnated access port was pushed through. The gelatin-impregnated access port was fixed to the sample stage of a scanning electron microscope (SEM, specifically, an IT-200 manufactured by JEOL Ltd.) so that the cross section of the gelatin-impregnated access port was facing upward. The cross section of the gelatin-impregnated access port was observed under the following conditions: Low vacuum mode: 30 Pa Detector: BED backscattered electron detector Acceleration voltage: 10 kV Probe current: 60 μA <1.4.1.2. Calculation of Porosity> The observed image was opened using image processing software called ImageJ, and the analysis range was cut out using a rectangular frame. At this time, the rectangular frame used to cut out the analysis range was a frame including a first side, a second side, a third side, and a fourth side. The first side of the rectangular frame is a line segment extending in the thickness direction of the gelatin-impregnated cylinder (see Example 1) on the observed image. The second side is a line segment passing through the intersection of the first side and the inner surface of the gelatin-impregnated cylinder and perpendicular to the first side. The third side is a line segment extending parallel to the first side at an interval of 0.5 mm. The fourth side is a line segment passing through the intersection of the first side and the outer surface of the gelatin-impregnated cylinder and perpendicular to the first side. The analysis range was binarized into pores and non-pores using ImageJ. Next, the porosity was calculated using ImageJ. The porosity was calculated using the following formula. Porosity = Area of ​​pores in analysis range / Area of ​​analysis range × 100 The porosity of each analysis range was determined for a total of two analysis ranges. The two analysis ranges were a first analysis range and a second analysis range located opposite each other via a cylindrical elastomer (see Example 1). The average value of these porosities is described in Example 1. <1.4.2. Laminate> A 76 razor blade (specifically, a 76 razor blade manufactured by Nisshin EM Co., Ltd.) was pressed against the top surface of the laminate, and then the laminate was pressed down. The laminate was fixed to the sample stage of a scanning electron microscope (SEM, specifically, an IT-200 manufactured by JEOL Ltd.) with the cross section of the laminate facing upward.The cross section of the laminate was observed under the same conditions as the gelatin-impregnated access port. The observed image was opened using image processing software called ImageJ, and the analysis range was then cut out. At this time, for the laminates of Preparation Examples B to D, the analysis range was cut out from the membrane after gelatin treatment in the observed image. On the other hand, for the laminates of Preparation Examples A and E, the analysis range was cut out from the porous membrane in the observed image. The analysis range was binarized into pores and non-pores using ImageJ. Next, the porosity was calculated using ImageJ. The porosity was calculated using the following formula: Porosity = Area of ​​pores in analysis range / Area of ​​analysis range × 100. The porosity of each analysis range was calculated for a total of two analysis ranges. The average porosity values ​​are shown in Table 2.

[0153] <2. Investigation of Gelatin Insolubilization> <2.1. Electron Beam Crosslinking> A 10% by mass aqueous solution of gelatin (LET-NP250 manufactured by Nitta Gelatin Co., Ltd.) was placed in a sealed container. The sealed container containing the 10% by mass aqueous solution of gelatin was irradiated with electron beams at 10 kGy, 20 kGy, 40 kGy, or 60 kGy using an electron beam irradiation device manufactured by Sumiju Atex Co., Ltd. Crosslinked gelatin was thus obtained.

[0154] 2.2. Insoluble Content 2 g of a sample (specifically, cross-linked gelatin or a 10% by weight aqueous solution of gelatin) was placed in a screw tube, and pure water was added to the screw tube. The resulting 2% by weight solution of the sample (hereinafter sometimes referred to as the "sample solution") was allowed to stand for 2 hours and then stirred at 40°C for 30 minutes. The sample solution was suction filtered using a polytetrafluoroethylene (PTFE) membrane filter (Omnipore, manufactured by Merck Ltd.) with a pore size of 10 μm. The screw tube was washed with pure water at 40°C, and the post-wash solution was recovered. This membrane filter was also used for suction filtering of the post-wash solution. The residue remaining on the membrane filter was washed with pure water at 40°C. The post-wash residue was heated at 110°C for 16 hours, and the weight of the residue (i.e., dry weight) was measured. The dry weight of 2 g of the sample (specifically, cross-linked gelatin or a 10% by weight aqueous solution of gelatin) was also measured. That is, 2 g of sample was heated at 110°C for 16 hours and then its weight was measured. The insoluble content was calculated from the dry weight of the sample and the dry weight of the residue using the following formula: Insoluble content = (dry weight of residue / dry weight of sample) × 100. In this formula, a value in grams is substituted for the dry weight of the residue. In this formula, a value in grams is also substituted for the dry weight of the sample. The table below summarizes the results of measuring the insoluble content. Note that the samples (specifically, cross-linked gelatin or a 10% by mass aqueous solution of gelatin) were also evaluated to determine whether they were in a sol or gel state at 40°C, i.e., whether they had fluidity at 40°C, and the results of this evaluation are also shown in this table. By irradiating with electron beams at 20 kGy, 40 kGy or 60 kGy, crosslinked gelatin which turned into a gel at 40° C. and had an insoluble content of about 40% or more could be obtained.

[0155] 3. Preparation of Porous Polyurethane Material 3.1. Preparation Example 1 Commercially available reagent sodium chloride (NaCl) was pulverized in an agate mortar. From this pulverized material, the component that passed through a 106 μm stainless steel sieve but not a 45 μm sieve was collected as a pore-forming agent. 10 parts by mass of polyurethane (Lubrizol, Pellethane 2363-80AE) and 90 parts by mass of dimethyl sulfoxide (DMSO) were mixed and dissolved at 90°C. This resulted in a 10% by mass polyurethane solution. One part by mass of pore-forming agent was added to one part by mass of the 10% by mass polyurethane solution, and the mixture was thoroughly stirred. This resulted in a porous polyurethane material stock solution. The porous polyurethane material stock solution was poured into a 2 mm high silicone rubber mold placed on a 1 mm thick first silicone rubber sheet. Next, a 1 mm thick second silicone rubber sheet was placed on the mold. This sandwiched the mold between a pair of silicone rubber sheets. These were then sandwiched between a pair of glass plates and cooled overnight in a -20°C freezer to solidify the polyurethane porous material stock solution in the mold. The flat membrane-like solidified material was removed from the mold and immersed in ice-cold water. This removed the DMSO and pore-forming agent. The solidified material was further washed with 60°C warm water. This was then dried under reduced pressure to obtain a flat membrane of polyurethane porous material. The porosity of the polyurethane porous material was 90.9% and the tensile modulus was 106 kPa.

[0156] 3.2. Preparation Example 2 A flat membrane of a polyurethane porous material was prepared in the same manner as in Preparation Example 1, except that no pore-forming agent was used (i.e., no pore-forming agent was added to the 10% by mass polyurethane solution). The porosity of the polyurethane porous material was 84.8%, and the tensile modulus was 665 kPa.

[0157] 3.3. Preparation Example 3 A flat membrane of a polyurethane porous material was prepared in the same manner as in Example 1, except that the amount of the pore-forming agent added was changed to 0.5 parts by mass. The porosity of the polyurethane porous material was 88.3%, and the tensile modulus was 182 kPa.

[0158] 3.4. Pore size distribution The pore size distribution (specifically, log differential pore volume distribution) of the polyurethane porous body of Preparation Example 1 was measured. As shown in Fig. 5, the pore size distribution (specifically, log differential pore volume distribution) of the polyurethane porous body of Preparation Example 1 showed a peak near a pore size of 10 µm and a series of peaks with pore sizes of 100 µm or more. The former (i.e., the peak near a pore size of 10 µm) is presumed to be a peak derived from pores formed by DMSO crystals. The latter (i.e., the series of peaks with pore sizes of 100 µm or more) is presumed to be a series of peaks derived from pores formed by the pore-forming agent.

[0159] 4. Preparation of Elastomer Sheet A 3 mm thick elastomer sheet was prepared by compression molding styrene-isoprene-styrene elastomer D1161 manufactured by KRATON using a hot press. The tensile modulus of the elastomer sheet was 730 kPa.

[0160] 5. Preparation of Laminates 5.1. Preparation Example A An elastomer sheet (hereinafter sometimes referred to as "EL sheet") measuring 10 mm in length and 5 mm in width was cut from an elastomer sheet. Separately, a flat membrane (hereinafter sometimes referred to as "porous membrane") measuring 10 mm in length and 5 mm in width was cut from the flat membrane of polyurethane porous material prepared in Preparation Example 1. The porous membrane was placed on the EL sheet, and several drops of heptane were added to the porous membrane. This allowed the heptane to penetrate the interface between the porous membrane and the EL sheet. Next, a 10 g weight was placed on the porous membrane on the EL sheet, and the porous membrane was air-dried. As a result, the porous membrane was adhered to the EL sheet. This procedure yielded a laminate comprising an EL sheet and a porous membrane laminated on the EL sheet. Micrographs of the interface between the EL sheet and the porous membrane are shown in Figures 6A and 6B. In these figures, the EL sheet is visible above the porous membrane.

[0161] 5.2. Preparation Example B The laminate prepared in Preparation Example A was immersed in a 10% by weight aqueous solution of gelatin (LET-NP250 manufactured by Nitta Gelatin Co., Ltd.). The laminate was placed in a desiccator (specifically, in a metal water bath within the desiccator, as described below), and the pressure in the desiccator was reduced to an absolute pressure of 6.3 kPa and maintained at 6.3 kPa for 10 minutes. That is, the laminate was left standing at 6.3 kPa for 10 minutes. During this time, the 10% by weight aqueous solution of gelatin was maintained at 50°C using a hot plate within the desiccator and a metal water bath placed on the hot plate. The pressure in the desiccator was then returned to normal pressure, i.e., an absolute pressure of 101.3 kPa, and the immersed laminate was removed from the container containing the 10% by weight aqueous solution of gelatin. The 10% by weight aqueous solution of gelatin adhering to the surface of the immersed laminate was removed with a doctor blade. The immersed laminate was then sealed in a sealed container. The sealed container containing the immersed laminate was irradiated with electron beams at 30 kGy using an electron beam irradiation device manufactured by Sumitomo Heavy Industries Atex Co., Ltd. This resulted in a laminate having an EL sheet and a gelatin-treated film laminated on the EL sheet. Figure 6C shows a micrograph of the interface between the EL sheet and the gelatin-treated film. In these images, the EL sheet is visible above the gelatin-treated film.

[0162] 5.3. Preparation Example C A laminate was prepared in the same manner as in Preparation Example B, except that instead of leaving the laminate at 6.3 kPa for 10 minutes, it was left at 31.3 kPa for 10 minutes. That is, the pressure inside the desiccator was reduced to an absolute pressure of 31.3 kPa, and the pressure was maintained at 31.3 kPa at 50°C for 10 minutes. A laminate was prepared in the same manner as in Preparation Example B. Figure 6D shows a micrograph of the interface between the EL sheet and the gelatin-treated film. In these figures, the EL sheet is visible on top of the gelatin-treated film.

[0163] 5.4. Preparation Example D A laminate was prepared in the same manner as in Preparation Example B, except that instead of leaving the laminate standing for 10 minutes at 6.3 kPa, it was left standing for 10 minutes at normal pressure. That is, the laminate was immersed in a 10% by mass aqueous solution of gelatin in a container, and then left standing for 10 minutes at normal pressure and 50°C. After immersion, the laminate was removed from the container. A laminate was prepared in the same manner as in Preparation Example B. Figure 6E shows a micrograph of the interface between the EL sheet and the gelatin-treated film. In these figures, the EL sheet is visible above the gelatin-treated film.

[0164] 5.5. Preparation Example E A laminate was prepared in the same manner as in Preparation Example A, except that the flat membrane of the polyurethane porous material prepared in Preparation Example 2 was used instead of the flat membrane of the polyurethane porous material prepared in Preparation Example 1.

[0165] <6. Results> The table summarizing the results is shown below. In this table, "absolute pressure" is the absolute pressure inside the desiccator at the time of immersion.

[0166] Although not shown in this table, the tensile modulus of the polyurethane (Pellethane 2363-80AE, manufactured by Lubrizol) used to prepare the polyurethane porous body was 12.6 × 10 ３ kPa, i.e., 12.6 MPa.

[0167] By making the polyurethane porous, the tensile modulus of elasticity could be reduced (see Preparation Examples 1 to 3). In particular, in Preparation Example 1, the Young's modulus of the skin on the palm side of the forearm (specifically, about 100±50 kPa) １） , and the Young's modulus of the skin on the back of the forearm (specifically, approximately 70±25 kPa) １） The tensile modulus was reduced to a level equivalent to that of

[0168] As shown in Fig. 7D, when the laminate produced in Production Example A was immersed in a 10% by mass aqueous solution of gelatin at normal pressure, the 10% by mass aqueous solution of gelatin did not penetrate into the pores (see Production Example D). Consistent with this, this method hardly reduced the porosity (see Production Example D). On the other hand, as shown in Fig. 7B and 7C, when the laminate produced in Production Example A was immersed in a 10% by mass aqueous solution of gelatin at reduced pressure, the 10% by mass aqueous solution of gelatin penetrated into the pores (see Production Examples B and C).

[0169] 7. Example 1—Preparation of Gelatin-Impregnated Access Port A cylindrical elastomer with a height of 3 mm and a diameter of 5 mm was cut from an elastomer sheet. As shown in FIGS. 8A and 8B , a cylindrical rod with a diameter of 5 mm and a mold including an inner wall capable of forming a cylindrical cavity concentric with the rod were prepared, and a tubular porous polyurethane body was molded. Specifically, the space between the rod and the inner wall (i.e., the tubular space) was filled with the polyurethane porous body concentrate prepared in Preparation Example 1. This was cooled overnight in a −20°C freezer. After cooling, the rod and mold were removed to obtain a tubular coagulated product, which was immersed in ice-cold water and then washed with warm water at 60°C. It was then dried under reduced pressure. This yielded a tubular porous polyurethane body. A cylindrical porous polyurethane body with a height of 3 mm (hereinafter sometimes referred to as a “porous polyurethane cylinder”) was cut from this tubular porous polyurethane body. A cylindrical elastomer was fitted into the inner cavity of the polyurethane porous cylinder (i.e., the cavity surrounded by the inner surface of the polyurethane porous cylinder) and adhered with heptane. The resulting pre-immersion access port was immersed in a 10% by weight gelatin aqueous solution (see Preparation Example B). The access port was then placed in a desiccator, and the pressure inside the desiccator was reduced to 6.3 kPa absolute and maintained at 6.3 kPa for 10 minutes. During this time, the 10% by weight gelatin aqueous solution was maintained at 50°C using a hot plate inside the desiccator and a metal water bath placed on the hot plate. The pressure inside the desiccator was then returned to normal pressure, i.e., 101.3 kPa absolute, and the post-immersion access port was removed from the container. The 10% by weight gelatin aqueous solution adhering to the surface of the access port after immersion was removed. The post-immersion access port was then sealed in a sealed container. After immersion, the sealed container containing the access port was irradiated with electron beams at 30 kGy using an electron beam irradiation device manufactured by Sumitomo Heavy Industries Atex Co., Ltd. This resulted in a cylindrical gelatin-impregnated access port with an outer diameter of 8 mm, which had a cylindrical elastomer and a gelatin-impregnated cylinder surrounding the cylindrical elastomer. Here, the gelatin-impregnated cylinder had a polyurethane porous cylinder surrounding the cylindrical elastomer, and cross-linked gelatin in the pores of the polyurethane porous cylinder.The porosity of the gelatin-impregnated cylinder in the gelatin-impregnated access port was 1.2%.

[0170] Notes 1) Liang X, Boppart SA. Biomechanical properties of in vivo human skin from dynamic optical coherence elastography. IEEE Trans Biomed Eng. 2010 Apr;57(4):953-9. doi: 10.1109 / TBME.2009.2033464. Epub 2009 Oct 9. PMID: 19822464; PMCID: PMC3699319.

[0171] 9... Vascular access device, 91... Artificial blood vessel, 92... Access port, 921... Vascular access portion, 923... First surface, 924... Second surface, 926... Surrounding portion, 61... Porous tube, 62... Thermoplastic elastomer layer, 12... Skin

[0172] 7...catheter, 71...tube, 72a...cuff, 72b...cuff

[0173] 8...catheter, 81...tube, 82...cuff, 85...branch, 86a...branch tube, 86b...branch tube, 87a...connector, 87b...connector, 88a...clamp, 88b...clamp

Claims

1. An access port comprising: a vascular access portion including a first surface for being pierced with a needle and a second surface from which the needle protrudes; and a peripheral portion surrounding the vascular access portion, wherein the vascular access portion contains an elastomer, and the peripheral portion comprises a porous body having communicating holes.

2. The access port according to claim 1, wherein the surrounding portion further comprises a biodegradable material having cell adhesive properties within the communication holes.

3. The access port according to claim 2, wherein the biodegradable material is at least one of a cross-linked gelatin gel and collagen.

4. The access port of claim 2, wherein the biodegradable material is a cross-linked gelatin gel.

5. The access port according to claim 1, wherein the porous body has at least one peak in a log differential pore volume distribution curve, the peak apex being in the pore diameter range of more than 100 μm and not more than 1000 μm.

6. The access port of claim 1, wherein the porous body comprises an elastomer.

7. The access port of claim 6, wherein said elastomer of said porous body is a thermoplastic polyurethane elastomer.

8. The access port according to claim 1, wherein the tensile modulus of the porous body is 40 kPa or more and 190 kPa or less.

9. The access port according to claim 1, wherein the peripheral portion includes an inner surface facing the vascular access portion and an outer surface opposite the inner surface, and the thickness from the inner surface to the outer surface is 0.5 mm or more and 2 mm or less.

10. A method for producing an access port according to any one of claims 2 to 4, comprising the steps of: immersing a pre-immersion access port comprising the vascular access portion and the porous body in an aqueous solution containing a water-soluble biodegradable material with cell adhesive properties under reduced pressure; increasing the atmospheric pressure of the aqueous solution in which the pre-immersion access port is immersed; and insolubilizing the water-soluble biodegradable material contained in the post-immersion access port.

11. A vascular access device comprising: an access port according to any one of claims 1 to 9; and an artificial blood vessel, wherein the second surface of the access port faces the artificial blood vessel.

12. A cuff for a catheter, comprising a porous body having communicating holes.

13. The catheter cuff according to claim 12, further comprising a biodegradable material having cell adhesive properties within the communication holes.

14. A catheter cuff as described in claim 12, wherein the tensile modulus of the porous body is 40 kPa or more and 190 kPa or less.

15. A catheter comprising the catheter cuff of claim 12.

16. The catheter of claim 15, which is a continuous ambulatory peritoneal dialysis catheter or a central venous catheter.

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