JP2006130004A - Method for manufacturing micro-catheter and micro-catheter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably manufacturing a narrow micro-catheter consisting of an inner layer, a reinforcing layer and an outer layer, with excellent operability; and the micro-catheter manufactured by the method. <P>SOLUTION: In the method for manufacturing the micro-catheter consisting of the inner layer, the reinforcing layer and the outer layer, the reinforcing layer has a braiding structure consisting of strands made of materials with different fusion points. The method for stably manufacturing the narrow micro-catheter with excellent operability and the micro-catheter manufactured by the method can be obtained by heating and fusing at least one of the strands spiralled only in one direction of the micro-catheter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a microcatheter inserted into a thin peripheral blood vessel and a microcatheter for the diagnosis or treatment of blood vessels and organs such as the brain, heart, and abdomen.

  Conventionally, a medical act of percutaneously inserting a catheter inserted into a blood vessel into an organ such as the brain, heart, or abdomen, and administering and injecting a therapeutic agent, an embolic substance, a contrast agent, or the like has been performed. In recent years, due to advances in medicine, it has become necessary to inject therapeutic agents, embolic substances, contrast agents and the like into finer peripheral blood vessels, and the development of microcatheters that can be inserted into these fine peripheral blood vessels has been desired. Since microcatheters need to be surely advanced by a surgeon's operation through a slender peripheral blood vessel, various operability is required. This operability includes pushability that reliably transmits the operator's pushing force to the tip of the microcatheter, and torque transmission that reliably transmits the rotational force applied by the operator to the tip of the microcatheter. The guide wire follows the guide wire that passes through the lumen of the microcatheter and travels in the bent blood vessel, and the kink resistance that does not cause the micro catheter to be bent even at the bent or curved portion of the blood vessel is raised. . In order to realize these operability, it is well known that the tip portion of the microcatheter is made of a flexible material and the end side thereof is made of a hard material. In order to secure kink resistance and pushability, a reinforcing layer having a braided structure or a coil structure is also used in many microcatheters.

However, although the kink resistance and pushability can be ensured by configuring the reinforcing layer, for example, when the braided structure is taken, it is difficult to reduce the diameter of the microcatheter because the wires constituting the braid overlap. Flexibility is difficult to secure. When the coil structure is adopted, the coils do not overlap, making it easier to reduce the diameter than the braided structure and the flexibility of the tip is good. There was a drawback that the handling property in the process such as coating was poor. Also, continuous production, which is easy with a tube with a braided structure, was difficult with a tube with a coil structure. As a method for solving these problems, for example, in Patent Document 1, a spiral wound with high mechanical strength only in one direction, and only in the other direction intersecting with the one spiral with low mechanical strength. A braided structure is disclosed which is composed of the other spiral wound around. By reducing the strength of one of the wound windings, kink resistance and torque transmission can be increased, but the intersecting portions of the windings are thick, making it difficult to reduce the diameter of the catheter. It was. Patent Document 2 discloses a structure in which a right-handed coil and a left-handed coil are stacked. Although this method improves torque transmission and pushability and improves handling in the process, it is difficult to reduce the diameter of the catheter, which is an advantage of the coil structure.
Japanese Patent No. 3184086 Japanese Patent Laid-Open No. 9-149938

  An object of the present invention is to provide a manufacturing method and a microcatheter that can easily and stably manufacture a microcatheter having good operability and a small diameter, which is the above-mentioned problem.

As a result of intensive studies for solving the above problems, the present inventor has found that the operability can be greatly improved and a small-diameter microcatheter can be stably manufactured by the following manufacturing method. That is, the present invention
(1) An inner layer, a reinforcing layer, and an outer layer, the reinforcing layer has a braided structure, the braid is made of strands of materials having different melting points, and at least one of the strands wound in one direction is an outer layer Using the melting point T _mo (° C) of the resin constituting the formula:
T _mfl <T _mo + 20
It is made of a resin _having a melting point T _mfl (° C.) represented by the following: a remaining wire wound in the same direction as the wire made of the resin and a screw only in the other direction intersecting with the one wound wire. The wound wire is expressed using T _mo (℃):
T _mo ≤ T _mfh and T _mfl <T _mfh
A microcatheter manufacturing method comprising a resin or a metal in represented by a melting point T _mfh (℃), by heating in T _mfl below (℃) or T _mfh (℃) temperature, the melting point T _mfl (° C. And a step of melting at least a part of the strand made of resin.
(2) All of the strands wound in one direction constituting the braided structure have the formula:
T _mfl <T _mo + 20
A method for producing a microcatheter, comprising a resin _having a melting point T _mfl (° C.) represented by:
(3) microcatheter before coating the outer layer resin, an intermediate tube consisting of an inner layer and the reinforcing layer is heated at T _mfl below (℃) or T _mfh (℃) temperature, characterized by subsequently coating the outer layer Manufacturing method.
And a microcatheter manufactured by these manufacturing methods.

  By being configured as described above, it is possible to provide a method for manufacturing a microcatheter and a microcatheter capable of providing a flexible tip at a small diameter while maintaining good operability. In addition, an effect of suppressing the opening of the braid, which has been a problem with the cut surface of the braided tube, can be obtained.

The microcatheter manufacturing method and microcatheter of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an overall view of a microcatheter to which the present invention is applied. The microcatheter of this embodiment has a catheter body 1 composed of an inner layer, a reinforcing layer, and an outer layer, a marker 2 attached to the distal end portion of the catheter, and a hub 3 provided at the proximal end of the catheter body.
The material constituting the inner layer is not particularly limited. For example, polytetrafluoroethylene, polytetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, tetrafluoroethylene / ethylene copolymer and other fluororesin, polypropylene And polyolefins such as polyethylene, nylon 6, nylon 66, nylon 12, polyamides such as polyamide elastomer, polyethylene terephthalate, polyester elastomer, polyurethane, polyurethane elastomer and the like.

The braided layer, which is a reinforcing layer, is composed of strands made of a material having different melting points that are wound. At least one of the constituent wires is an expression:
T _mfl <T _mo + 20
It is made of a resin _having a melting point T _mfl (° C) represented by the following formula:
T _mo ≤ T _mfh and T _mfl <T _mfh
It is made of a resin or metal _having a melting point T _mfh (° C.) represented by Examples of resins _{having a} melting point T _mfl (° C.) include polyolefins such as polypropylene and polyethylene, nylons 6, nylon 66, nylon 12, polyamides such as polyamide elastomer, polyesters such as polyethylene terephthalate and polyester elastomer, polyurethane, polyurethane Examples include elastomers, and these materials may be combined depending on the desired mechanical properties. Examples of resins _{having a} melting point T _mfh (° C.) include polyolefins such as polypropylene and polyethylene, nylons 6, nylon 66, nylon 12, polyamides such as polyamide elastomer, polyesters such as polyethylene terephthalate and polyester elastomer, polyurethane, polyurethane Elastomers, aramids, polyarylates, etc., examples of metals include stainless steel or highly radiopaque materials such as tungsten, platinum, iridium, gold, etc., depending on the desired mechanical properties and radiopacity. These materials may be combined.

  The material constituting the outer layer is not particularly limited. For example, nylon 6, nylon 66, nylon 12, polyamides such as polyamide elastomer, olefins such as polyethylene, polypropylene, polymethyl methacrylate, and modified polyolefin, polyethylene terephthalate, polybutylene terephthalate, Examples thereof include polyesters such as polyester elastomers, polyurethanes, polyurethane elastomers, polymer blends thereof, polymer alloys, and the like.

The constituent material of the inner layer, the reinforcing layer, and the outer layer can be used in any combination from these resins and metal materials, but the strands of the wire wound in one direction constituting the braided layer that is the reinforcing layer At least one must select a resin having a melting point T _mfl (℃), all the wires that are other Nishimaki, it is necessary to select a resin or metal having a melting point T _mfh (℃). The resin material may contain various additives such as a contrast agent, a plasticizer, a reinforcing article, and a pigment in addition to the polymerization aid used at the time of polymerization.

  The shape of the wound wire constituting the braid of the reinforcing layer may be a round wire having a circular cross section or a flat wire having a square cross section. A round wire is preferred when two or more wires are wound. The diameter of the round wire may be 0.10 mm or less, preferably 0.01 mm or more and 0.05 mm or less, and the thickness of the flat wire may be 0.1 mm or less, but is preferably 0.01 mm or more and 0.05 mm or less. If the diameter of the round wire and the thickness of the flat wire are 0.10 mm or more, the microcatheter becomes thick and sufficient flexibility cannot be obtained. If it is less than 0.01 mm, it may be frequently cut in the braiding process, and the operability such as kink resistance and pushability of the microcatheter may be lowered.

At least one strand made of a resin _{having a} melting point T _mfl (° C.) may be selected. One direction of the braid is wound with two or more strands, at least one of which is made of a resin having a melting point T _mfl (° C), and the remaining strand and the other spiral strand are melted. In the case of a resin or metal of T _mfh (° C.) (FIGS. 2 and 3), the outer layer is covered after a braided structure is formed by a generally performed braiding process. Normally, when coating the outer layer, the outer layer must be sufficiently melted and coated, so the resin constituting the outer layer is heated to a temperature 20 ° C. higher than the melting point T _mo (° C.) and extruded or shrink-molded. The When the outer layer is subjected to heating at a temperature higher than the melting point T _mo (° C.) of the resin constituting the outer layer by 20 ° C. or more, that is, T _mfl (° C.) or more and less than T _mfh (° C.), the melting point T Part or all of the strand made of _mfl (° C) resin melts. Resin of the molten melting point T _mfl (° C.) is embedded in the gap of the wire made of a resin or a metal of the other melting T _mfh (℃). By eliminating some of the strands that make up the braided structure, it becomes a structure that has both the characteristics of the braided structure and the coil structure, so pushability, torque transmission, etc. that are the operability required for microcatheter While ensuring the operability, it is possible to provide flexibility of the tip and a reduction in the diameter of the catheter. Furthermore, by resin melting point T _mfl (° C.) is embedded in the gap of the resin or strands made of a metal of the molten other melting T _mfh (° C.), the outer layer sheath of the microcatheter of the prior braided structure The problem that it was difficult to coat the outer layer resin smoothly and thinly from the surface irregularities due to the braiding is also solved at the same time.

As another form of the microcatheter that can be used in the present invention, one is _{wound with} one strand made of a resin of T _mfl (° C.) (FIG. 4), or is wound with two or more strands. And when all of one strand is comprised with resin of melting _| fusing point _Tmfl ( _degreeC ) (FIG. 5, FIG. 6), after taking a braided structure by the generally performed braiding process, as mentioned above, _Tmfl ( the heating of less ° C.) or higher T _mfh (° C.) to receive in coating the outer layer, a part or all of the wire made of a resin melting T _mfl (° C.) is melted. When the temperature for coating the outer layer is not higher than 20 ° C. higher than the melting point T _mo (° C.) of the resin constituting the outer layer, the strands having a braided structure may be heated and melted in advance. Resin of the molten melting point T _mfl (° C.) is embedded in the gap of the wire made of a resin or a metal of the other melting T _mfh (℃). At the same time, the strand made of resin with melting point T _mfl (° C) melts, and the strand moves to the inner layer by the winding force of the other strand made of resin with melting point T _mfh (° C) can do. As described above, when one strand is melted and the other strand moves to the inner layer side, it is possible to realize a smaller diameter than the braided structure. Furthermore, since one of the strands is melted, a pseudo-coil structure can be formed, so that the flexibility of the tip can be improved. Since the first braided structure is adopted, the handling property before coating the outer layer is good with no pitch deviation as compared with the coil structure.

Further, in the present invention, it is embedded in the gap of the molten melting point T _mfl resin (℃) are composed of a resin or a metal of the other melting T _mfh (℃) wire, screw the molten resin is not melted Since it is embedded in the gap between the windings, the effect of suppressing the opening of the braid, which has been a problem with the cut surface of the braided tube, is also obtained.

Composed of a resin having a melting point T _mo of the resin constituting the outer layer when coating the outer layer (° C.) 20 ° C. or higher than a temperature, i.e. T _mfl (° C.) or more heating at the melting point T _mfl (° C.) in the above Although the strands are melted, if the heating when coating the outer layer is T _mfl or less, or if the strands are melted in advance, the intermediate tube consisting of the inner layer and the reinforcing layer before coating the outer layer is made of T _{The same} effect can be obtained by heating at a temperature of _mfl (° C.) or higher and _lower than T _mfh (° C.) and then coating the outer layer.
When the outer layer is coated, the strand made of the resin having the melting point T _mfl (° C.) is melted by heating at a temperature higher than the melting point T _mo (° C.) of the resin constituting the outer layer, but the outer layer is covered. an intermediate tube of before the inner and the reinforcing layer is heated at T _mfl below (℃) or T _mfh (℃) temperature, the same effect can be obtained by subsequently coating the outer layer.

As described above, by changing the ratio of the resin or wire made of a metal having a melting point T _mfl made of a resin (℃) strand and the melting point T _mfh (℃), microcatheter having various excellent operability Can be obtained.

The outer layer may be coated by extrusion or may be shrunk using a heat shrinkable tube. A method for forming the inner layer, the reinforcing layer, and the outer layer will be described below. As the extrusion molding method, for example, on the inner layer made of a fluororesin coated with an annealed copper wire, one is a strand made of a resin _{having a} melting point T _mfl (° C.), and the other is a resin having a melting point T _mfh (° C.) or An intermediate tube is obtained by braiding metal wires to form a braid. Further, the outer layer is formed by extruding a resin constituting the outer layer on the braid. In this extrusion molding, it is more preferable to continuously give a hardness gradient in the longitudinal direction by switching extrusion. Next, a method of shrinking using a heat shrinkable tube will be described. After the intermediate tube is constructed in the same manner as the above extrusion molding method, a hollow tube molded from a resin that forms an outer layer by extrusion is separately covered with the intermediate tube, and a heat shrinkable tube is further covered thereon. It is obtained by shrinking the covered tube in a heating furnace and then removing the heat shrinkable tube.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail according to an Example, this invention is not limited to a following example.

Example 1
A stainless steel wire (0.030 mm in diameter) was placed horizontally on one side (left-handed) on a core material coated with polytetrafluoroethylene (PTFE) at a thickness of 0.030 mm on a silver-plated annealed copper wire with a diameter of 0.52 mm. The intermediate tube was produced by winding the polypropylene fiber (melting point: 165 ° C., diameter: 0.030 mm) and five stainless steel fine wires side by side on the other side (right winding). Then, using polyamide elastomers (melting point 160 ° C-melting point 174 ° C) with Shore hardness 30D, 55D, 70D, each polyamide elastomer is supplied to three extruders connected before the crosshead die and melted. Mix and extrude into the intermediate tube. The temperature of the crosshead die is set to 210 ° C, the rotation speed of the gear pump attached to the tip of the extruder is continuously changed by computer control, the outer diameter and resin are changed, and the rigidity is continuously changed. A tube was prepared. The obtained tube had an outer diameter varying from 0.80 mm to 0.90 mm. A microcatheter was produced by attaching a marker to the distal end side and a hub to the proximal side, with the softest part being the distal side and the hardest part being the proximal side. In the obtained microcatheter, the polypropylene fibers constituting the braided structure are melted and filled in the gaps of the stainless steel fine wires, and the irregularities derived from the braided structure are seen even at the smallest outer diameter of 0.80 mm. It showed a good appearance. The tip showed good flexibility, and there was no significant difference between the left and right in torque transmission, and operability such as kink resistance was also good.

(Example 2)
As a braided structure, 5 stainless steel wires (diameter 0.030mm) are wound side by side on one side (left-handed), and 5 polypropylene fibers (melting point 165 ° C, diameter 0.030mm) are placed on the other side (right-handed). An intermediate tube was obtained in the same manner as in Example 1 except that it was wound in a state of being arranged side by side. A microcatheter was produced by coating the outer layer in the same manner as in Example 1 except that a tube having an outer diameter of 0.75 mm to 0.85 mm was obtained. The obtained microcatheter had a pseudo-coil structure because all of the polypropylene fibers constituting the braided structure were melted and filled in the gaps between the stainless steel fine wires. In addition, the unevenness derived from the braided structure was not seen even at the smallest part with an outer diameter of 0.75 mm, and the appearance was good. The tip showed good flexibility and operability such as kink resistance was also good.

(Example 3)
After producing an intermediate tube in the same manner as in Example 1, it was covered with a heat-shrinkable tube made of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and heated in a heating furnace at 180 ° C. for 5 minutes. After removing the heat-shrinkable tube, a microcatheter was produced in the same manner as in Example 1. The outer diameter of the obtained tube was 0.80 mm to 0.90 mm as in Example 1. The obtained microcatheter was good in appearance and operability like the microcatheter of Example 1.

(Comparative Example 1)
As a braided structure, a microcatheter was obtained in the same manner as in Example 1 except that five stainless steel wires (0.030 mm in diameter) were wound side by side on both sides. The outer diameter of the obtained microcatheter was changed from 0.80 mm to 0.90 mm in the same manner as in Example 1. However, the portion with a small outer diameter had surface irregularities that seem to be derived from the braided structure, and the appearance was not good. Torque transmission and pushability were good, but the tip was hard and lacked flexibility.

1 is an overall view of a microcatheter of the present invention. It is the schematic which shows the braiding structure in the Example of this invention. It is the schematic which shows the braiding structure in the Example of this invention. It is the schematic which shows the braiding structure in the Example of this invention. It is the schematic which shows the braiding structure in the Example of this invention. It is the schematic which shows the braiding structure in the Example of this invention.

Explanation of symbols

1 Catheter body 2 Marker 3 Hub 11 _{Wire made} of resin with melting point T _mfl (° C) 12 _{Wire made} of resin or metal with melting point T _mfh (° C)

Claims (4)

It consists of an inner layer, a reinforcing layer, and an outer layer, and the reinforcing layer has a braided structure, the braid is made of strands of materials having different melting points, and at least one of the strands wound in one direction constitutes the outer layer Using the melting point T _mo (° C) of the resin, the formula:
T _mfl <T _mo + 20
It is made of a resin _having a melting point T _mfl (° C.) represented by the following: a remaining wire wound in the same direction as the wire made of the resin and a screw only in the other direction intersecting with the one wound wire. The wound wire is expressed using T _mo (℃):
T _mo ≤ T _mfh and T _mfl <T _mfh
A microcatheter manufacturing method comprising a resin or a metal in represented by a melting point T _mfh (℃), by heating in T _mfl below (℃) or T _mfh (℃) temperature, the melting point T _mfl (° C. And a step of melting at least a part of the strand made of resin. All of the strands wound in one direction that make up the braided structure have the formula:
T _mfl <T _mo + 20
The method for producing a microcatheter according to claim 1, comprising a resin _having a melting point T _mfl (° C.) represented by: _{3. The} intermediate tube composed of the inner layer and the reinforcing layer is heated at a temperature of T _mfl (° C.) or higher and _lower than T _mfh (° C.) before coating the outer layer resin, and then the outer layer is coated. The manufacturing method of the microcatheter of description.   A microcatheter manufactured by the manufacturing method according to claim 1.

Images