JP2016123764A - High density medical fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a graft for branch type stent-graft, which has a water permeability and burst strength required as an implant material, realizing a fine diameter, and capable of preventing leakage of liquid as much as possible by using specific fabric at a branch part.SOLUTION: There is provided a high density medical fabric, stent-graft in which the high density medical fabric is used as graft, and medical delivery catheter into which the compressed stent-graft is inserted, in which the high density medical fabric is seamless, having cylindrical shape and comprising a branch part. Both warp and weft removed from the fabric are made of multifilament synthesized fiber having 60 dtex or less of total denier. A part of fabric tissue at boundary of the large diameter part and the branch part is constructed as single layer tissue. In addition the fabric meets the following requirements (1) to (4): (1) cover factor is 1600 to 2400, (2) thickness is 90 μm or less, (3) burst strength is 100 N or more and (4) coefficient of water permeability is 300 ml/cm/min or less.SELECTED DRAWING: None

Description

  The present invention relates to a high-density fabric for medical use. More specifically, the present invention relates to a seamless and cylindrical high density fabric for medical use having a fabric performance such as a thin thickness, a high strength, and an excellent water permeability, particularly a graft having a branch portion for a stent graft.

  Recent advances in medical technology are rapidly changing the treatment of aortic aneurysms from artificial blood vessel replacement to less invasive stent grafts. Conventional artificial blood vessel replacement is a large-scale surgical operation due to thoracotomy or laparotomy, which places a heavy physical burden on the patient and has limited application to the elderly and patients with comorbidities. There is a problem that the medical burden on the patient and the medical facility is large because it requires hospitalization treatment. On the other hand, in stent graft treatment, transcatheter endovascular treatment using a stent graft in which a stent having a role of maintaining a cylindrical shape with a metal is combined with a graft such as a medical fabric or a membrane made into a cylindrical shape (foot) By inserting a thin catheter into which the stent graft is compressed and inserted from the root artery, and fixing the stent graft at the site of the aneurysm, the blood flow to the aneurysm is prevented and the aneurysm is prevented from rupturing) Since it does not involve thoracotomy or laparotomy, the physical and economic burden is reduced, and in recent years, its indication has been rapidly expanding.

  However, the current stent graft has a large stent metal wire diameter and graft thickness, and since it cannot be folded down to a small diameter, it has only a large catheter diameter and cannot be applied to women with thin arteries or Asians such as Japanese. There are many cases. In order to make the stent graft thinner, it is necessary to devise the shape of the metal stent, the metal wire diameter, etc., but the stent graft is basically fixed to the affected area by pressing against the blood vessel wall with the metal expansion force. Therefore, there is a limit to improvement that affects the expansion force such as reducing the stent wire diameter. On the other hand, thinning of the graft, which occupies most of the volume of the stent graft, is desired. For example, if the e-PTFE membrane is thin, there is a risk that the membrane may be stretched and ruptured with time due to the expansion force and blood pressure of the stent. is there. Further, in a graft made of a woven fabric or a knitted fabric composed of fibers, if the thickness is reduced, blood leakage from the graft itself occurs, and the therapeutic effect is not seen. In particular, in a bifurcated stent graft used for the treatment of an abdominal aortic aneurysm, liquid leakage from the boundary portion branched from the aorta to each lower limb tends to occur, and this problem becomes more apparent as the ground becomes thinner. In addition, elongation and bending stresses are likely to be applied to the bifurcation, and tearing may occur in the membrane type graft. In the woven type, the boundary is sewn by hand-sewing or the end surface treatment is performed with a thermal cutter. Measures have been taken to prevent blood leaks and tears from the parts, but none are sufficient.

  The following Patent Documents 1 to 3 disclose grafts having a branched portion. Patent Document 1 discloses a structure in which each blood vessel wall of a branching part is shared or connected in a bridge shape. However, a specific weaving structure and placement location are not shown, and this is applied to reality. It is difficult. Patent Document 2 discloses a branched graft shape, but relates to opening and closing of blood flow to the side surface. Further, Patent Document 3 discloses a method of arranging a stent at a branch portion, but does not show a specific woven structure or the like of the branch portion. As described above, there has been no suggestion of an effective method for the branch type graft boundary portion, and in reality, there is a situation in which liquid leakage from the graft boundary portion is concerned.

  The present inventors made a prototype of these branched stent grafts of the prior art and evaluated their characteristics, but the problem of leakage from the boundary portion remained as a concern. As described above, a graft for a branch type stent graft as a medical material has not yet been obtained as a medical fabric having a branch portion capable of simultaneously solving the problems of prevention of liquid leakage and diameter reduction in a medical field. It is a fact.

JP-A-64-32857 JP2013-158352A JP-A-8-280816

  The problem to be solved by the present invention is a seamless and cylindrical medical use that can be reduced in diameter as an implantable material and has a necessary water permeability and burst strength, and is used for a graft for a branched stent graft. Is to provide a high density fabric.

  As a result of intensive studies and experiments, the present inventors have found that a graft for a branched stent graft is made of a woven fabric, and that the branched portion has a specific woven structure, leading to prevention of liquid leakage. The present invention has been completed.

That is, the present invention is as follows.
[1] A seamless and cylindrical high-density medical fabric having a large-diameter portion and a branched portion, and both warps and wefts taken out from the fabric are composed of multifilament synthetic fibers having a total fineness of 60 dtex or less. A part of the woven fabric structure at the boundary between the diameter portion and the branching portion is composed of a single tissue, and the woven fabric includes the following (1) to (4):
(1) Cover factor is 1600-2400,
(2) The thickness is 90 μm or less,
(3) burst strength is 100 N or more, and (4) water permeability is 300 ml / cm ² / min or less,
The high density fabric for medical use satisfying the above.
[2] The medical high-density fabric according to [1], wherein the number of warps constituting the single structure is 2 to 32.
[3] The medical high-density fabric according to [1] or [2], wherein a polyester multifilament synthetic fiber having a single yarn fineness of 0.5 dtex or less is used as a part of warp and / or weft.
[4] The high-density medical fabric according to any one of [1] to [3], which is woven by a loom using a shuttle in which wefts are wound around a pipe.
[5] A stent graft using the medical high-density fabric according to any one of [1] to [4] as a graft.
[6] A medical delivery catheter in which the stent graft according to [5] is compression-inserted.

  The seamless and cylindrical high-density fabric for medical use according to the present invention has water permeability and rupture strength necessary as an implantable material, can be reduced in diameter, and has a specific woven structure at a branching portion. Is useful as a graft for a branched stent graft that can minimize liquid leakage.

A fabric structure in which a single structure is not formed in both the large diameter part and the branched part is shown. The fabric structure in which a single structure is formed in both the large diameter part and the branched part is shown. A woven structure formed by a single structure only in the large diameter portion is shown. The textile structure in which a single structure is formed only by a branch part is shown. The stainless rod inserted in the cylindrical fabric of a large diameter part for mold fixation at the time of heat setting is shown.

Hereinafter, embodiments of the present invention will be described in detail.
The total fineness of the multifilament synthetic fiber used for the fabric of this embodiment needs to be 7 dtex or more and 60 dtex or less from the viewpoint of thinning and strength of the stent graft fabric. If the total fineness of the fibers used is less than 7 dtex, the thickness of the woven fabric is reduced, which meets the needs for reducing the diameter of the stent graft, but is not practical in terms of strength. On the other hand, if the total fineness exceeds 60 dtex, the thickness of the woven fabric exceeds 90 μm, which is not suitable for reducing the diameter. For example, when a tubular woven fabric having an inner diameter of 50 mm is used, it cannot pass through a hole having a diameter of 6 mm (assuming a catheter having an inner diameter of 6 mm). The total fineness is preferably 10 dtex or more and 50 dtex or less, more preferably 15 dtex or more and 40 dtex or less, from the viewpoint of achieving both a thin fabric and practical performance.

  The preferred single yarn fineness when used as the warp and / or the weft of the fabric of this embodiment is 0.5 dtex or less. When the single fiber fineness is 0.5 dtex or less, the affinity with the vascular endothelial cells increases, and the integration of the vascular wall tissue and the fabric progresses. it can. From the viewpoint of fabric thinning and cell affinity, the single yarn fineness of the fiber is preferably 0.4 dtex or less, more preferably 0.3 dtex or less. The lower limit of the single yarn fineness is not particularly limited, but is preferably 0.01 dtex or more, more preferably 0.03 dtex, from the viewpoint of process passability such as warping and weaving processing as a textile manufacturing process and expression of bursting strength of the textile. That's it.

The cover factor of the fabric of this embodiment needs to be 1600-2400. When the cover factor is less than 1600, it means that the woven density of the fabric is sparse, and blood leakage from the fabric itself is likely to occur. On the other hand, when the cover factor exceeds 2400, the density increases and the function of preventing blood leakage works. However, there are problems that the fabric itself is hard and difficult to fold and is not suitable for diameter reduction. The cover factor is preferably 1800 to 2300, more preferably 2000 to 2200. The cover factor in the warp direction and the cover factor in the weft direction are preferably about the same, but is not particularly limited, and the larger the cover factor in the warp direction, the easier the production of the high-density fabric.
The cover factor (CF) is calculated by the following formula:
CF = √ (dw × Mw + df × Wf)
{In the formula, dw is the total fineness (dtex) of the warp extracted from the woven fabric, Mw is the woven density of the warp (main / 2.54 cm), and df is the total fineness (dtex) of the weft extracted from the woven fabric. Yes, and Mf is the weave density of the weft yarn (lines / 2.54 cm). }.

  The fabric of this embodiment is a seamless tubular fabric. As a graft for a stent graft, it is possible to use a sheet-like woven fabric or membrane in the shape of a cylinder, and bond the ends together with an adhesive or sew them together by sewing, but the thickness of the bonded or sewn part In order to reduce the diameter, a seamless woven fabric is preferable. In addition, the configuration in which wefts are continuously connected to each other can eliminate the complicated and manual variation process such as pasting and sewing that are performed when using a non-cylindrical flat fabric or film material. The liquid leakage can be reduced, and further, it is effective for a smooth blood flow by eliminating surface irregularities.

  As a basic woven structure of the woven fabric of the present embodiment, except for a single woven structure, a plain woven fabric, a twill woven fabric, a satin woven fabric and the like can be used, but are not particularly limited, but from the viewpoint of thinning and strength of the woven fabric, blood leakage reduction. Is preferably a plain weave structure. The warp density and the weft density of the woven fabric are each preferably 100 / 2.54 cm or more, more preferably 120 / 2.54 cm or more. The upper limit is not particularly limited, but is substantially 250 / 2.54 cm or less in terms of weaving.

The thickness of the fabric of this embodiment needs to be 90 μm or less. When the thickness exceeds 90 μm, the diameter is not reduced when folded, and may not be accommodated in a desired catheter. Therefore, the thickness is preferably in the range of 10 to 70 μm. Thus, a delivery system that can be easily released from the catheter even when released at the diseased part can be obtained. When the thickness of the woven fabric is thinner than 10 μm, sufficient burst strength cannot be maintained. Here, the thickness of the woven fabric is the average of values measured using a thickness gauge at 10 locations arbitrarily selected within the circumferential direction and the length direction (5 cm to 30 cm) of the tubular woven fabric. Defined by value. In measuring the thickness of the fabric, the following formula:
Z (%) = (Zav−Zi) / Zav × 100
{In the formula, Zav is an average value of 10-point measured values, and Zi is a measured value at each point, and i is an integer of 1 to 10. } It is preferable that the thickness variation Z at each measurement point represented by} is all within ± 15%.
If the thickness variation exceeds -15% and is large on the minus side, even if the average thickness of the woven fabric when folded is 90 μm or less, it may not be accommodated in a desired catheter such as a hole with a diameter of 6 mm. In addition, the portion where the thickness variation exceeds 15% is thin, and the bursting strength and water permeation prevention performance are impaired. The thickness variation Z is more preferably within ± 12%, still more preferably within ± 10%.

  For example, the thickest blood vessel in which a stent graft is used is the thoracic aorta, usually having an inner diameter of about 40 to 50 mm. In order to reduce the patient's physical burden and increase the number of patients, the thoracic aorta is required to be able to insert a stent graft with a maximum inner diameter of 50 mm into a catheter of 18 French (inner diameter 6 mm) or less, but passes through a hole with a diameter of 6 mm. The present inventors have clarified that the thickness of a cylindrical fabric having an inner diameter of 50 mm is 90 μm at the maximum, and this thickness is large even when the inner diameter of the cylindrical fabric is changed. Since there is no change, in determining the single yarn fineness and the total fineness of the ultrafine polyester fiber used in the stent graft fabric, the thickness of the fabric is 90 μm or less.

The water permeability of the fabric itself of this embodiment needs to be 300 cc / cm ² / min or less. The water permeability of the woven fabric serves as an index for preventing blood leakage. When the water permeability is 300 cc / cm ² / min or less, blood leakage from the fabric wall surface can be suppressed to a low level. The water permeability of the woven fabric is preferably 250 cc / cm ² / min or less, more preferably 200 cc / cm ² / min. Next, the fabric of the graft is finished with a metal stent and a suture thread to finish the stent graft, which is the final product. When a large needle hole is opened in the fabric, blood leaks therefrom. That is, in the medical fabric of this embodiment, the water permeability before and after needle sticking is 300 cc / cm ² / min or less, and the water permeability after needle sticking is preferably 300 cc / cm ² / min or less as practical performance. . Here, the water permeability after needle sticking is a value measured after using a taper-shaped 3/8 needle and optionally passing 10 needles per 1 cm ² . In order to reduce the needle hole, it is effective to use extra fine polyester fiber. This is because the single yarn filament is spread with a needle in the woven structure, but the gap between the warp and weft intersection is soft because the single yarn filament is soft. It is buried and the needle hole is hard to remain, and the water permeability before needle stick is kept low.

  The woven fabric of this embodiment needs to have a burst strength measured according to the burst strength test of ANSI / AAMI / ISO 7198: 1998/2001 standard of 100 N or more. When the rupture strength of the woven fabric is less than 100 N, when used as a stent graft woven fabric, there is a problem in terms of safety at the time of use such as rupture by the expansion force of the stent. The burst strength is preferably 120 N or more, more preferably 140 N or more. Although there is no restriction | limiting in particular in the upper limit of the bursting strength of a textile fabric, it becomes 500 N or less substantially from a viewpoint of the balance with thinning of a textile fabric.

It is preferable that the porosity in the cross section of the warp and the weft constituting the woven fabric of the present embodiment is 10% or more and 70% or less. By forming a void of 10% or more in the woven fabric, it becomes easier for cells to enter between the single yarn fibers, and the integrity of the vascular wall tissue and the woven fabric is increased (effect of preventing blood leakage and stent graft migration) as described above. The water permeability after needle sticking can be suppressed to 300 cc / cm ² / min or less. On the other hand, when the porosity of the woven fabric exceeds 70%, the woven fabric loses its shape, causing an increase in water permeability. The porosity of the woven fabric of the present embodiment is more preferably 15% or more and 60% or less, more preferably 20% or more and 50% or less, and the porosity may be increased as the single yarn fineness decreases.

  The crimp rate of the wefts extracted from the fabric of this embodiment is preferably 4% or more and 20% or less. This is because, when the crimp rate is 4% to 20%, the flexibility in the circular cross section is increased, the shape following property in the blood vessel is improved, and the burst strength and the water permeability are also improved. When the crimp rate is less than 4%, end-leak is likely to occur because of lack of flexibility in the circular cross section. On the other hand, when the crimp rate exceeds 20%, the thickness of the woven fabric increases, which is not suitable for reducing the diameter. The crimp rate is more preferably 6% to 18%, and more preferably 8% to 15%.

  Similarly, the crimp rate of the warp extracted from the fabric of this embodiment is preferably 0.2% or more and 5% or less. When the crimp rate is 0.2% to 5%, a strong woven fabric structure is obtained in the warp direction, and bending and twisting of the graft are less likely to occur. When the crimp rate is less than 0.2%, the balance between warp and weft is not good, so the burst strength and water permeability after needle puncture tend to be disturbed, and the weft easily slips on the warp, resulting in yarn misalignment. Blood leaks. On the other hand, when the crimp rate exceeds 5%, the woven fabric is less rigid in the vertical direction and is not suitable for pulsation stability. The crimp rate is more preferably 0.3% or more and 3% or less, and more preferably 0.4% or more and 2.5% or less.

The branch part of the woven fabric of this embodiment is divided into two or more branch parts continuously from the cylindrical large diameter part, and one part of the woven fabric structure at the boundary part between the large diameter part and the branch part. The department needs to be a single tissue. For example, FIG. 1 shows a woven structure constituting a woven fabric when the thick part is divided into two branch parts. As shown in FIG. 2, it can be set as the structure which provided the single structure | tissue in both the large diameter part and the branch part. Moreover, as shown in FIG. 3, it is good also as a structure which provided the single structure | tissue only in the large diameter part. Furthermore, as shown in FIG. 4, a single tissue may be provided only at the branch part, but as shown in FIG. 2, it is preferably provided at both the large diameter part and the branch part.
The single structure only needs to be a structure that joins the upper and lower fabrics. For example, as a structure that is not excessive on the woven structure, a 2/2 diagonal structure, a 2/2 twill structure, or a 3/3 diagonal structure A tissue, a 3/3 woven structure, or the like may be used, and a woven structure such as 1/2 畝, 2/1 畝, or flat may be used, and may be selected as long as there is no problem in weaving or handling.

  The branch part of the fabric of this embodiment may have a difference in diameter, or may be a plurality of three or more branches. The length of the bifurcation may be the same, but generally one branch is longer than the other, which compresses a stent graft with a long bifurcation from one iliac artery, for example, in the treatment of an abdominal aneurysm This is because a stent graft having a short bifurcation is inserted and joined from the other iliac artery after insertion with the inserted catheter and placement with an aneurysm.

The number of warp yarns constituting the single structure is preferably 2 to 32. Moreover, it is preferable that a single structure exists in each of the branch parts, and it is more preferable that the single structure exists in each branch part depending on the size, rather than being concentrated in one of a plurality of branches. When the number of warp yarns constituting a single structure is less than two, one warp is formed at any branch part in the branch part, and the single structure has a structure with weak inter-thread restraint to reduce liquid leakage. Can not do it. In addition, when the number of warps exceeds 32, the single tissue part occupies a large diameter and the diameter of the cylinder near the branch part becomes small, which may hinder the smooth flow of blood, or more than necessary. Even if a single tissue part is provided, the effect is not much different. The number of warps is preferably 4 to 16, and there is little liquid leakage and the influence of inhibiting blood flow is small.
Further, the number of wefts constituting the single structure can be composed of the same number of yarns as the warp, but is not particularly limited.

When weaving the woven fabric of the branch portion of this embodiment, for example, the warp yarn constituting the other branch portion when weaving one side of the weave is kept waiting at the upper opening, but waiting at the lower opening. It may be allowed to be used, and it is only necessary to form a woven structure in a pattern that is easy to weave. There are no particular restrictions when the number of warp yarns is small and the load of the jacquard machine or dobby machine is small, such as a graft base fabric. . Moreover, when weaving the fabric which has a branch part of this embodiment, it is preferable to provide the number of shuttles which added the large diameter part to the number of the branch parts. For example, when weaving two branch parts, it is preferable to prepare three shuttles in which wefts are stored. However, since it is possible to weave one of the branches by weaving the large-diameter portion, weaving is also possible with two shuttles.
The woven fabric of this embodiment may be coated with collagen, gelatin or the like within a range not departing from the requirements such as thickness and outer diameter.

  The fabric of this embodiment is used as a stent graft in combination with a stent (spring-like metal) that becomes an expandable member. Examples of the stent graft type include a cylindrical simple straight type, a branch type that can handle branch vessels, and a fenestration type. As the expandable member, a self-expanding material using a shape memory alloy, a superelastic metal, or a synthetic polymer material can be used. The expandable member can be any prior art design. The expandable member is applicable to a type that is expanded by a balloon instead of the self-expanding type. In the stent graft as a preferred embodiment of the present invention, the size of the gap between the stent and the graft is preferably within 2 mm.

  The fiber used in the present embodiment is preferably a polyester fiber. In particular, the ultrafine polyester fiber preferably has a tensile strength of 3.5 cN / dtex or more and a tensile elongation of 12% or more. When the tensile strength of the ultrafine polyester fiber is 3.5 cN / dtex or more, excellent mechanical properties can be exhibited as a fabric for stent graft. On the other hand, it is possible to increase the tensile strength of the polyester fiber by increasing the draw ratio. For example, even if the tensile strength is increased to 3.5 cN / dtex or more by stretching, the toughness is reduced when the tensile elongation is less than 12%. Inferior, leading to tears and breaks due to impact. In light of stable weaving processability of the woven fabric, the tensile strength of the ultrafine polyester fiber of the present embodiment is more preferably 3.8 cN / dtex or more, and still more preferably 4.0 cN / dtex or more. From the same viewpoint, the tensile elongation of the ultrafine polyester fiber of the present embodiment is more preferably 15% or more, and further preferably 20% or more.

  For at least a part of the warp and / or the weft of the fabric of the present embodiment, an ultrafine polyester fiber may be used, and all the wefts may be used for an ultrafine polyester fiber or a part of the fabric. Alternatively, it is also possible to use extra fine polyester fibers every few. The same applies to the warp, and it may be used for a part or all of the warp and the weft, and the use ratio can be determined according to the application. Ultra-fine polyester fiber is prone to fluff due to its small single-fiber fineness, but it may be coated with glue or oil to form a film on the yarn. You may improve handling.

  When weaving the woven fabric of this embodiment, the warp may be twisted at 50 to 1000 T / m, and a paste, an oil agent, or a WAX agent may be further added to the twisted yarn, and the twisted yarn may not be applied. It is also effective to improve the weaving property by suppressing the fluff during weaving by applying only the paste, the oil agent, and the WAX agent. However, from the viewpoint of biological safety, no glue is preferable, and it is preferable to warp the warp yarn only by twisting 300 to 700 T / m. However, even in this case, the spinning oil at the time of producing the raw yarn is adhered to the warp. In addition, the weft may be further provided with a spinning oil or other oil agent, or may be twisted at about 50 to 200 T / m to reduce friction and improve the weaving property. You may take the method.

  Examples of materials other than the ultra fine polyester fibers constituting the woven fabric of this embodiment include polyester fibers, polyamide fibers, polyethylene fibers, and polypropylene fibers that are outside the above-described range. These may be monofilaments or multifilaments, and can be used in combination with one or two or more kinds of fiber materials according to the purpose. As an aspect of the combination, the polyester fiber of this embodiment and other fibers are twisted together. It can be used as a composite fiber, and other fibers can be used as warp or weft of a woven fabric, or can be used partially as a part thereof.

  In addition, it is preferable that the content rate of PET component is 98 weight% or more, ie, the content rate of components other than PET is less than 2 weight%, as for an ultrafine polyester fiber. Here, the components other than PET are components incorporated into the molecular chain by copolymerization, etc., copolymerized PET attached to the surface of the polyester fiber, polyamide, polystyrene and copolymers thereof, sea-island type ultrafine PET such as polyethylene, polyvinyl alcohol, etc. The sea component polymer used at the time of fiber production and the decomposition product of the sea component polymer. In this embodiment, PET-derived monomers / oligomers such as ethylene glycol, terephthalic acid (TPA), monohydroxyethylene terephthalate (MHET), and bis-2-hydroxyethyl terephthalate (BHET) are included in the components other than PET. It is preferably not included. When the content of components other than PET is 2% by weight or more, these components are eluted in the body when embedded, and there is a concern of causing heat generation or a foreign body reaction. The content of components other than PET in the ultrafine polyester fiber is preferably less than 1% by weight, more preferably less than 0.5% by weight, and still more preferably not contained.

  The fabric of the present embodiment is a polyester fiber, in particular, the ultra-fine polyester fiber is effective as a constituent fiber of an implantable material such as an artificial blood vessel, an artificial fiber fabric, an anti-adhesive agent, and an artificial valve, as well as a stent graft fabric. Function. In addition to the implantable material, it effectively functions as a constituent fiber as a medical material such as a blood filtration material, a cell separation membrane, a cell adsorbing material, or a cell culture substrate outside the body. Of course, the polyester fiber, in particular, the ultra-fine polyester fiber can be used as a raw material for clothing, a filter, a wiping material and the like in addition to the medical field.

  In the present embodiment, the fabric suitable for stent graft is preferably a fabric from the viewpoint of strength development and blood leakage prevention. Further, from the viewpoint of thinning the fabric, the fabric of this embodiment needs to be composed of 20% by weight or more of ultrafine polyester fiber. When the composition ratio of the ultra fine polyester fiber of this embodiment is less than 20% by weight, the thickness of the fabric exceeds 90 μm, and it is difficult to realize a reduction in diameter. Further, when the composition ratio of the ultrafine polyester fiber is less than 20% by weight, the integrity with the stent is inferior. In the woven fabric of this embodiment, the composition ratio of the ultrafine polyester fiber is preferably 30% by weight or more, more preferably 40% by weight or more. In addition, although the ultrafine fiber of this embodiment can be used for both the warp and the weft of the woven fabric, it is particularly preferable to use it for the weft from the viewpoint of improving the integrity with the stent.

  In the method for producing ultrafine polyester fibers suitable for use in the fabric of this embodiment, a finishing agent is applied to the fiber bundle, and the subsequent warping and weaving process can be made good, and the finish As the agent, an oil agent derived from mineral oil, a water-soluble oil agent, or the like is used. Further, the oiling rate of the finishing agent is preferably 1% by weight or more and 3% by weight or less, more preferably 1.2% by weight or more and 2.8% by weight or less, from the viewpoint of bulkiness processing or weaving / knitting process passability. More preferably, it is 1.5 wt% or more and 2.5 wt% or less.

  In the manufacturing method of the ultrafine polyester fiber used in the present embodiment, it is possible to reduce the fluff and yarn breakage in the aging process and the process of weaving or weaving by applying the entanglement process in the undrawn yarn stage or the drawn yarn stage It is preferable from the viewpoint of improving the unraveling property, and the entanglement process employs a known entanglement nozzle, and the number of entanglement is preferably in the range of 1 to 50 / m. Furthermore, the ultrafine polyester fiber used in the present embodiment is an ultrafine polyester fiber used for weaving from the viewpoint of ensuring a heat shrinkage stress of 0.05 cN / dtex or more as an ultrafine polyester fiber constituting the woven fabric of the final stent graft product (after sterilization treatment). The thermal shrinkage stress of the polyester fiber is preferably 0.2 cN / dtex or more in a temperature range of 80 ° C. or more and 200 ° C. or less.

  The stent graft as a preferable aspect of the present embodiment is inserted into a catheter and transferred within a blood vessel. The stent graft of the present embodiment has a thin fabric thickness of 90 μm or less and high flexibility, so that it can be inserted into a catheter with a small diameter, and as a result, it can be easily transferred into the blood vessel and can damage the blood vessel wall. Is reduced. In addition, as a catheter, the thing of a prior art, such as a tube type and a balloon type, is used suitably. In addition, the stent graft inserted in the thin-diameter catheter of this embodiment can be transferred and placed in a blood vessel using a conventional delivery system. When the tubular seamless fabric of this embodiment is used as a stent graft fabric, the diameter of the stent graft can be reduced, so that it is possible to reduce the physical and economic burden on the patient, such as shortening the hospitalization period, and vascular wall damage. Etc. can also be reduced. Furthermore, the scope of application can be expanded to cases that have been excluded from indications for transcatheter endovascular treatment, such as women with fine arteries and Asians.

  Hereinafter, the production of the fabric of this embodiment will be described. In the step of preparing the warp constituting the woven fabric of the present embodiment, the warp beam may be wound on the loom by taking up the required number of warps on the warp beam with a warping machine, or wound on the creel. The warp may be pulled directly from the body onto the loom.

  The loom used to manufacture the seamless tubular fabric of this embodiment is not particularly limited, but it is seamless to use a shuttle loom that passes a weft by reciprocating movement of a shuttle (shuttle). It is suitable for making a woven fabric, and is preferable for suppressing the woven density variation of the woven fabric ear (the folded portion of the tubular woven fabric) and making the woven fabric uniform in thickness. When using a shuttle loom, if there are two branches, weave using three shuttles, and use each shuttle for one of the large diameter part, one of the branch parts, and the other of the branch parts. That's fine. Alternatively, when two shuttles are used, one of the large diameter portion and the branch portion can be woven with one shuttle, and the other of the branch portions can be woven with the other shuttle. In addition, it is effective for weaving a high-quality cylindrical fabric without wrinkles to make the tension at the time of unwinding the weft from the shuttle, and it is preferable to have a structure using a plurality of springs and the like. .

  Further, in the weaving of the tubular woven fabric as in the present embodiment, the entire surface of the temple (for the purpose of stabilizing the pre-weaving, uniforming the thickness and diameter of the woven fabric, or suppressing yarn breakage during processing, etc. Alternatively, a full width temple may be used. It is preferable to select a material with a small coefficient of friction for the entire temple member in contact with the woven fabric, or to use a material that has a tackiness and is hard to slip and has a smooth surface. The structure of the entire temple and the friction coefficient of the member to be used may be appropriately designed and selected depending on the single yarn fineness and total fineness of the yarn to be used and the weave density of the warp and weft.

Next, when weaving a tubular seamless woven fabric, it is necessary to control the raising and lowering of the warp. As a device therefor, a jacquard opening device or a dobby opening device can be used. It is particularly preferable to use an electronic jacquard to facilitate the organization of the tissue.
After weaving, scouring treatment for the purpose of removing oils, etc. and heat setting for the purpose of form stability are performed, but the scouring temperature / treatment time, heat setting temperature / treatment time, and the tension in these processes are particularly It is not limited.

  When heat setting the woven fabric of this embodiment, use a stainless steel tube having a diameter of a large diameter part and a diameter of a branch part, and the one whose tip is narrowed, and the diameter is reduced by a single structure near the branch part. It is preferable to manufacture a metal jig for heat setting with reduced thinning. In this case, from the viewpoint of workability, the large diameter and the branch are manufactured separately, a metal jig is inserted into the fabric to be heat set from above and below, and the structure can be fixed in the fabric, with the desired diameter. It is preferable to fix the woven fabric without wrinkles.

The treated fabric is combined using a stent and suture. What is necessary is just to select the joining conditions of a textile fabric and a stent according to the shape of a stent. The needle used for suturing is not particularly limited, but it is preferable to select a needle that has a water permeability of 300 cc / cm ² / min or less after needle sticking. Next, the stent graft obtained by the above method is sterilized. The conditions for the sterilization treatment are not particularly limited, but may be selected based on the balance between the sterilization effect and the heat shrinkage stress of the ultrafine polyester fiber after the treatment.

  Hereinafter, the present invention will be specifically described, but the present invention is not limited to these examples. The main measured values of physical properties were measured by the following methods.

(1) Total fineness / single yarn fineness The total fineness (dtex) is a value obtained by cutting a fiber bundle into a fixed length, measuring the weight (g) of the yarn, and converting it to a weight (g) per 1000 m. . The single yarn fineness (dtex) is a value obtained by dividing the total fineness obtained by the above method by the number of single yarns.

(2) Tensile strength and tensile elongation Tensile strength and tensile elongation were measured according to JIS-L-1013.

(3) Burst strength of woven fabric The burst strength test of a woven fabric was carried out in accordance with ANSI / AAMI / ISO 7198: 1998/2001 at n = 5, and the average value of the maximum test force at that time.

(4) Water permeability of fabric The water permeability of a fabric is measured according to ANSI / AAMI / ISO 7198: 1998/2001. In the water permeability test, measurement is performed at n = 5, and the average value is taken.

(5) Permeability of the tubular fabric at the branch (water permeability including the boundary (l / min)
The water permeability is measured with reference to ANSI / AAMI / ISO 7198: 1998/2001. A cylindrical medical fabric having a branching portion is prepared having a total length of 100 mm, a large diameter portion of 50 mm, and a branching portion having a length of 50 mm. The large-diameter portion of the woven fabric is covered with a metal tube whose periphery is covered with rubber, and the circumferential shape is firmly fixed with a metal band and tightened so as not to leak. At this time, the length from the metal band tip to the boundary portion (boundary between the large diameter portion and the branch portion) is set to 30 mm. However, the metal tube has a hollow structure sufficient for water to pass through.
Similarly, the tip of the branch portion is also covered with a metal tube covered with rubber, and the circumference is firmly fixed with a metal band and tightened so as not to leak. The length from the metal band tip to the boundary is 30 mm. The measurement is performed at n = 5, and the average value is taken.

(6) Thickness of woven fabric The thickness of the woven fabric is measured by n = 5 using a thickness gauge with a load of 1 N, and the average value is shown.

(7) Crimp rate The warp and the weft extracted from the woven fabric were carried out in accordance with the JIS L1096 8.7b method. Twenty yarns were measured and indicated as an average value.

(8) Porosity The fabric is embedded with a resin such as Technonov (Kulzer Co. Germany), and a 3 μm-thick section is prepared with a glass knife, and a photograph is taken with a 400 × optical microscope. From the measurement of the area of the fiber part and the fiber gap part on the photograph, the porosity is calculated by the following formula.
Porosity (%) = (area occupied by ultrafine fiber bundles−area occupied by individual ultrafine fiber bundles) / (area occupied by ultrafine fiber bundles) × 100
The image area measurement uses general image processing computer software such as NIH image.

(9) Catheter Insertability A fabric with sutured stents was appropriately folded to evaluate whether or not it could be inserted into a catheter having a cylindrical inner diameter of 6 mm. The case where it was able to be inserted without difficulty was marked with ◯, the case where it was difficult to handle was marked with △, and the case where it was impossible was marked with ×. Five each are prepared and evaluated.

[Examples 1 to 3]
As the warp, a polyester fiber having a total fineness of 36 dtex / single yarn fineness of 1.5 dtex is used as a warp, and as a weft, an ultrafine polyester fiber having a total fineness of 26 dtex / single yarn fineness of 0.17 dtex is used. In a shuttle loom equipped with an electronic jacquard opening device, a branched tubular seamless woven fabric was produced using three shuttles. The large-diameter portion was woven with the number of warps being 670, the width of warp passing through the cocoon was 50.0 mm, the density of the cocoons was 16.8 wings / cm, and 8 wings / wing. Next, for the branch portion, the warp yarn is divided at the center and 335 pieces are used for the left and right branch portions, respectively, and the fabric structure of the boundary portion is formed according to FIG. Weaving was performed with the number of warp yarns provided for 24 being 24 (Example 1). Similarly, the weave structure of the branch part is set as shown in FIG. 3, and a single structure is formed only by the large diameter part, and weaving is performed with the number of warp yarns provided to the single structure being 20 (Example 2). Weaving was also performed with the woven fabric structure of FIG. 4 that formed a single-layered structure alone (Example 3). In addition, the warp of the fraction is braided and woven with an appropriate number (the same applies to the following).

[Examples 4 to 6, Comparative Example 1]
In a shuttle loom equipped with an electronic jacquard opening device as in Examples 1 to 3, using polyester fibers having a total fineness of 36 dtex / single yarn fineness of 1.5 dtex as the warp and weft. A branched tubular seamless woven fabric was prepared using three shuttles. The large-diameter portion was woven with 562 warps, a thread width of 49.2 mm, a warp density of 19.1 / cm, and 6 / blade. Next, for the branch part, the warp yarns are divided at the center and 281 pieces are used for the left and right branch parts respectively, the woven fabric structure of the boundary part is 24 according to FIG. Weaving was performed so that a single structure was formed (Example 4). Similarly, the woven fabric structure of the large diameter part and the branched part was woven according to FIG. 1 which does not form a single structure (Comparative Example 1). Furthermore, the number of warp yarns provided to the single structure was set to 4 (Example 5) and 44 (Example 6), and the single structure was woven using the woven structure obtained by reducing and enlarging FIG. 2 as a single structure.

[Examples 7 and 8, Comparative Example 2]
Subsequently, in Example 4, the weft density was changed, and the weft density was 80 / 2.54 cm (Comparative Example 2), 121 / 2.54 cm (Example 7), 180 / A fabric of 2.54 cm (Example 8) was produced.

[Comparative Example 3]
In Example 1, a polyester fiber having a total fineness of 36 dtex / single yarn fineness of 1.5 dtex was used as the weft, and the finished weft density was 190 / 2.54 cm (Comparative Example 3). A woven fabric was prepared.

[Example 9, Comparative Example 4]
As the weft, weaving was performed as a polyester fiber having a total fineness of 48 tex / single yarn fineness of 0.46 dtex of the yarn extracted from the woven fabric (Example 9), and the weft extracted from the woven fabric was 90 dtex / single yarn fineness. Weaving was performed in place of a polyester false twisted yarn of 5 dtex (Comparative Example 4).

[Example 10]
As the warp yarn, an extra fine polyester fiber having a total fineness of 27 dtex / single yarn fineness of 0.18 dtex is used as the warp yarn, and an extra fine polyester fiber having a total fineness of 30 dtex / single yarn fineness of 0.2 dtex as the weft yarn is used. In a shuttle loom equipped with an electronic jacquard type opening device in the same manner as in Example 1, a branched tubular seamless woven fabric was produced using three shuttles. The large-diameter portion was woven with 650 warps, a thread width of 49.7 mm and a warp density of 32.8 wings / cm, and 4 wings / wings. Next, for the branch part, the warp yarn is divided at the center and 325 pieces are used for the left and right branch parts respectively, the woven fabric structure at the boundary part is 24 according to FIG. Weaving was performed so that a single structure was formed (Example 10).

These woven fabrics were subjected to scouring and heat setting under the following processing conditions to produce branched tubular fabrics. In addition, weaving the large-diameter part and the two branch parts using their respective shuttles, the switch from the shuttle that weaved the wefts of the large-diameter part at the boundary to the shuttle of the wefts that weave each branch part. Thus, the weft is not continuous at the boundary.
The stainless steel rod inserted into the large-diameter cylindrical fabric for mold fixing during heat setting has a cylindrical shape with a diameter of 25 mm, its tip is a little flat, and the branching portion is a cylindrical shape with a diameter of 12 mm. Structure. In the heat setting, a stainless steel rod having a shape as shown in FIG. 5 was used, but the shape and thickness of the tip of the large-diameter portion and the branching portion were appropriately changed according to the shape of the woven structure at the boundary and the target density. It is preferable to make a tubular woven fabric without wrinkles. In particular, it is necessary to produce a stainless steel rod in consideration of the fact that the diameter of the tubular woven fabric becomes small due to a single structure or the like at the branch portion.

  The properties of the finished fabric (Examples 1 to 10 and Comparative Examples 1 to 4) after finishing the treatment are as shown in Table 1. In the examples, the thickness, the burst strength, the water permeability of the normal base fabric portion, and the branching. It turns out that it is excellent in the water permeability in a part. Moreover, in Comparative Example 1, since there is no single texture in the woven fabric structure before and after the branching portion, the water permeability including the branching portion is high due to the occurrence of openings in the branching portion. Since the water permeability is high, the water permeability including the bifurcation is also high. In Comparative Examples 3 and 4, since the thickness was large, the graft diameter after folding was large and was not suitable for thinning.

(Scouring conditions)
Washing with stirring in an aqueous sodium carbonate solution (concentration: 5 g / l) at 98 ° C. for 1 hour.
・ Repeat 30 minutes of stirring and washing with 98 ° C ultrapure water three times.
-Dry at a constant length in the biaxial direction at room temperature.
(Heat setting condition)
・ Scouring and passing the dried fabric through a stainless steel core rod of φ50mm × 200mm length preheated to 180 ° C in a thermostatic bath, both ends of the 200mm length fabric were hung using a hose band. Set and fix so that there is no slack.
-A stainless steel core rod with a fixed fabric is put into a constant temperature bath at 180 ° C, and heat setting is performed for 20 minutes after the temperature in the constant temperature bath is controlled at 180 ° C.
(Sterilization conditions)
-Heat treatment for 30 minutes in a thermostatic chamber at 185 ° C.

  The woven fabric according to the present invention can be reduced in diameter as an implantable material, and can be used for a graft for a branch stent graft having a necessary burst strength and water permeability. It can be suitably used as a high-density fabric.

Claims (6)

A seamless and cylindrical high-density medical fabric having a large-diameter portion and a branched portion, both warps and wefts taken from the fabric are composed of multifilament synthetic fibers having a total fineness of 60 dtex or less, and the large-diameter portion A part of the woven fabric structure at the boundary portion of the branch portion is composed of a single tissue, and the woven fabric includes the following (1) to (4):
(1) Cover factor is 1600-2400,
(2) The thickness is 90 μm or less,
(3) burst strength is 100 N or more, and (4) water permeability is 300 ml / cm ² / min or less,
The high density fabric for medical use satisfying the above.   The medical high-density fabric according to claim 1, wherein the number of warps constituting the single tissue is 2 to 32.   The medical high-density fabric according to claim 1 or 2, wherein a polyester multifilament synthetic fiber having a single yarn fineness of 0.5 dtex or less is used as a part of warp and / or weft.   The medical high-density fabric according to any one of claims 1 to 3, woven with a loom of a type using a shuttle in which wefts are wound around a pipe.   A stent graft using the high-density medical fabric according to any one of claims 1 to 4 as a graft.   A medical delivery catheter in which the stent graft according to claim 5 is compression-inserted.