JPH05253304A - Blood vessel catheter - Google Patents

Abstract

PURPOSE:To achieve higher safety with the prevention of damage to an internal wall of a blood vessel by a method wherein a main part of a catheter main body having an inner tube with high rigidity and an outer tube with rigidity lower than the inner tube and moreover, the outer tube sticks out by a specified length from the tip of the inner tube. CONSTITUTION:A catheter body 2 has a main part which is arranged to be a double structure which comprises an inner tube 4 and an outer tube 5 joined closely on the external surface thereof 4 and the inner tube 4 is made of a material with higher rigidity while the outer tube 5, a soft material. The catheter body 2 is made up of a base part 6 of a double structure, an intermediate part 7 and a tip part 8 having the outer tube 5 alone in the order from the mounting end side. At the base part 6, the outer diameter of the catheter body 2 is almost constant in the longitudinal direction of the tip 22. At the intermediate part 7, the outer diameter of the catheter body 2 decreases gradually toward the tip 22 while the inner tube 4 also has the outer diameter thereof decreasing gradually toward the tip 22. Thus, the thickness of the inner tube 4 becomes thin gradually and the rigidity thereof decreases continuously. At the tip part 8, the inner tube 4 lacks. With the outer tube 5 alone, the outer diameter of the catheter body 2 decreases gradually in the direction of the tip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vascular catheter used for endovascular surgery, superselective injection of drugs such as anticancer drugs, and angiography.

[0002]

2. Description of the Related Art In recent years, intravascular treatment for treating vascular lesions and lesions rich in blood vessels (aneurysm, arteriovenous malformation tumor, etc.) by percutaneously inserting a catheter into the blood vessel without surgical operation. Surgery is flourishing. In such a procedure, an angiocatheter must be inserted into a specific portion of a thin vascular system that has a tortuous, intricately bent and branched structure.

[0003] For example, in endovascular surgery called embolization performed on aneurysms and arteriovenous malformation tumors found in cerebral blood vessels and the like, the tip of a thin vascular catheter is selectively selected to the affected area in the brain or its vicinity. After insertion, a liquid embolic material such as cyanoacrylate or a solution of ethylene-vinyl alcohol copolymer in dimethylsulfoxide, a granular embolic material such as polyvinyl alcohol granules, and a coil are injected from the tip of the blood vessel catheter. As described above, for administration of a drug or injection of a contrast agent into a thin blood vessel, a blood vessel catheter having a diameter corresponding thereto is used.

Therefore, such a small-diameter angiocatheter has, in addition to the chemical and biological safety required for a normal angiocatheter, a rapid and reliable selectivity for a thin and complicated pattern of vascular system. In order to inject the above-mentioned embolic substance, chemical resistance, particularly solvent resistance that does not cause deterioration when contacted with a solvent such as dimethyl sulfoxide, is required. To be done.

Further, the above-mentioned operability of the blood vessel catheter will be described in detail. The pushing force of the operator for inserting the blood vessel into the blood vessel can be surely transmitted from the proximal end side to the distal end side of the catheter; Torque transferability that the rotational force applied at the proximal end side can be reliably transmitted to the distal end side, and it can proceed smoothly in a curved blood vessel along a guide wire previously inserted without damaging the inner wall of the blood vessel. Trackability (hereinafter referred to as “trackability with respect to the guide wire”)
Or simply “followability”) and kink resistance that prevents the catheter from bending at the curved or bent part of the blood vessel even after the catheter tip reaches the target position and the guide wire is pulled out. To be done. Furthermore, lubricity (sliding property due to reduction of friction coefficient) of the outer surface of the catheter is required as one of the largest factors for imparting these properties to the catheter.

Among these, as a conventional technique for imparting pushability and followability to a guide wire,
A blood vessel catheter having a double-tube structure in its main length, which is composed of a relatively hard inner tube and a relatively soft outer tube that covers the outer surface of the inner tube and has a portion protruding from the tip of the inner tube. Has been developed and used. In such a blood vessel catheter, the following combinations have been proposed as constituent materials for the inner tube and the outer tube.

According to Japanese Utility Model Publication No. 60-500013 and corresponding US Pat. No. 4,385,635, polyamide is used for the inner tube and urethane is used for the outer tube, and the tip of the inner tube is formed in a tapered shape so that the inner diameter thereof gradually increases. A vascular catheter is disclosed. However, in this blood vessel catheter, since the outer tube is made of urethane, it has poor solvent resistance and is not suitable for a catheter used for embolization.

Further, according to the present invention, since the rigidity changes abruptly at the boundary portion where the double tube portion of polyamide and urethane moves to the single tube portion of urethane, the catheter body is likely to be bent (kink). There are also drawbacks. Particularly, in the urethane single tube portion, the outer diameter and the inner diameter are constant, and the rigidity does not gradually decrease toward the tip, so that stress concentration occurs at the boundary portion where the double tube changes to the single tube. This is a cause of kinking, and also has poor followability. In particular, there are some reports that, after repeated intravascular operations, the boundary between the double pipe and the single pipe was severed in severe cases due to material fatigue.

Japanese Utility Model Publication No. 62-17082 discloses a vascular catheter using silicon rubber for the outer tube and a hard resin selected from polyethylene, polypropylene, fluororesin and hard vinyl chloride resin for the inner tube. .. This vascular catheter has solvent resistance (excluding hard vinyl chloride resin), but at the boundary between the double-tube portion (main body portion 4) and the single-tube portion (tip portion 3), the tube lumen Since a step corresponding to the thickness of the inner pipe is formed in the inner tube, bending is likely to occur at this portion, and the kink resistance is poor. In addition, the kink resistance is similarly inferior even in a combination of a polypropylene inner tube which has been put into practical use in recent years and an outer tube made of an ethylene-vinyl acetate copolymer.

In Japanese Unexamined Patent Publication No. 59-156353, a vascular catheter in which a tubular body on the base side made of nylon and a tip portion made of a polyether-polyamide copolymer are fused to appropriately show flexibility of the tip portion. Is disclosed. However, this angiocatheter does not have a double-tube structure, but is made by fusing and connecting different materials. Therefore, there is a risk of cutting at the fusion site and a step is formed on the outer surface.
There is a drawback that the inner wall of the blood vessel may be damaged when the catheter is inserted, and a special manufacturing apparatus must be used for fusion of the polymer.

US Pat. No. 4,636,346 discloses a guiding catheter having a main part of a triple tube structure and a tip part of a double tube structure (which lacks the intermediate layer of the main part) extending distally from the triple tube structure. Has been done. Since this catheter is a guide catheter for inserting another catheter into the lumen (lumen) and guiding it to the target site, it is assumed that the inner diameter of the lumen should be as large as possible. Therefore, it is practically difficult to apply to the above-mentioned small-diameter angiocatheter.

Further, all of the above-mentioned vascular catheters have poor lubricity on their outer surfaces and poor slidability in blood vessels, so that the vascular catheter can be safely and quickly delivered to the target site in a short time. It was difficult to reach.

[0013]

The object of the present invention is to provide excellent operability such as pushability, followability, and kink resistance, less vascular damage, and excellent safety, especially in the procedure for small-diameter blood vessels. Another object is to provide a suitable vascular catheter.

[0014]

These objects are achieved by the present invention described in (1) to (8) below.

(1) It has a double tube structure consisting of an inner tube and an outer tube that adheres to the outer surface of the inner tube, and has a catheter body with a lumen formed inside from the proximal end to the distal end. A blood vessel catheter in which the bending elastic modulus of a tube is higher than that of the outer tube, wherein the catheter body has a base portion having an outer diameter substantially constant in the longitudinal direction, the base portion including the inner tube and the outer tube, and the base portion. An intermediate portion formed by the inner tube and the outer tube extending from the distal end toward the distal end of the catheter body, and at least the outer diameter of which gradually decreases toward the distal end, and from the distal end of the intermediate portion toward the distal end of the catheter body. A distal end portion formed of the outer tube that extends toward the distal end and has an outer diameter that gradually decreases toward the distal end. The bending rigidity of the catheter body gradually decreases from the intermediate portion to the distal end portion, and the base portion and the intermediate portion A vascular catheter characterized in that the outer surface of the catheter body forms a continuous and smooth surface in the vicinity of the boundary with the section and in the vicinity of the boundary between the intermediate section and the tip section.

(2) The blood vessel catheter according to (1), wherein the outer diameter of the inner tube in the intermediate portion gradually decreases toward the distal end.

(3) The blood vessel catheter according to (1) or (2), wherein the thickness of the outer tube at the distal end portion gradually decreases in the distal direction.

(4) Flexural modulus of the inner tube (ASTM
D-790, 23 ℃) 1500-15000kg / cm ²
The vascular catheter according to any one of (1) to (3) above, which is

(5) The blood vessel catheter according to any one of the above (1) to (4), wherein the inner tube is made of a polyamide elastomer.

(6) The bending elastic modulus (ASTM D-790, 23 ° C.) of the outer tube at the tip portion is 5 to 15
The vascular catheter according to any of (1) to (5) above, which has a dose of 00 kg / cm ² .

(7) The blood vessel catheter according to any one of the above (1) to (6), wherein the outer tube is made of a polyester elastomer.

(8) The above (1) to (7), wherein the outer surface of the catheter body is covered with a hydrophilic polymer substance.
The vascular catheter according to any one of 1.

[0023]

In the blood vessel catheter of the present invention, the main part of the catheter body is composed of a double tube in which an inner tube having a high rigidity and an outer tube having a lower rigidity are combined, and further, the outer portion from the tip of the inner tube. Since the tube protrudes a certain length to form a flexible catheter tip, it can be used for not only ordinary arteries and veins having a relatively large diameter, but also for minute and complicated vessels such as cerebral blood vessels and other peripheral blood vessels. It exhibits excellent pushability, followability, and kink resistance even in a blood vessel, has reliable selectivity at a blood vessel bifurcation, and is highly safe.

More specifically, in the blood vessel catheter of the present invention, in the double-tube structure portion, the outer diameter of the catheter body is substantially constant in the longitudinal direction and the outer diameter of the catheter body is directed toward the distal end. It is composed of a gradually decreasing intermediate portion, and further, on the distal end side of the intermediate portion, only a flexible outer tube is formed, and since the outer diameter gradually decreases toward the distal end, a distal end portion is formed. It exhibits excellent pushability and torque transmissibility over time, and the rigidity of the catheter body continuously decreases over almost the entire area from the middle section to the tip section, so it is excellent for guidewires inserted into bent blood vessels. It also exhibits excellent followability and prevents bending (kinks).

In this case, since the outer diameters of the intermediate portion and the distal end portion gradually decrease toward the distal end, the insertion property (running property) when pushing the catheter into the blood vessel and the selection at the blood vessel bifurcation part. It is highly likely. In addition, since the outer surface of the catheter body forms a continuous smooth surface without steps at the boundary between the base and the intermediate portion and the boundary between the intermediate portion and the distal end, There is little irritation and no damage.

Further, the outer diameter of the inner pipe in the middle portion is gradually reduced toward the tip end, that is, by forming the outer surface of the inner pipe in a tapered shape, and by selecting the material and the size, the inner pipe and the outer pipe are selected. By appropriately adjusting the elastic modulus of the pipe, abrupt changes in rigidity and stress concentration at the boundary are eliminated, and kinks are less likely to occur. In particular, the inner tube made of polyamide elastomer or polyester elastomer has relatively high rigidity at around room temperature, so it has excellent pushability and is flexible near body temperature. The kink property is further enhanced.

Further, when the outer surface of the catheter body is covered with a hydrophilic polymer substance, a lubricous surface is formed in contact with blood or the like, and the operability in the blood vessel is further improved, and the inner wall of the blood vessel is improved. Safety is further enhanced without damaging the.

[0028]

DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail with reference to the preferred embodiments shown in the accompanying drawings. FIG. 1 is a plan view showing an example of the overall configuration of the blood vessel catheter of the present invention, and FIG. 2 is an enlarged vertical sectional view showing the configuration near the distal end portion of the blood vessel catheter shown in FIG. In FIG. 2, in order to facilitate understanding,
The diametrical direction of the blood vessel catheter is particularly enlarged and schematically shown.

As shown in FIG. 1, the blood vessel catheter 1 of the present invention comprises a catheter body 2 and a hub 11 attached to a proximal end 21 of the catheter body 2. The catheter body 2 has a lumen 3 formed therein from a base end 21 to a tip 22 thereof. The lumen 3 serves as a flow path for a drug solution or the like, and a guide wire is inserted into the lumen 3 when the blood vessel catheter 1 is inserted into a blood vessel.
The hub 11 functions as an injection port for a drug solution or the like into the lumen 3 and an insertion port for the guide wire, and also as a grip portion when operating the vascular catheter 1.

As shown in FIG. 2, the catheter body 2 is
The main part thereof has a double pipe structure including an inner pipe 4 and an outer pipe 5 which is in close contact with and joined to the outer surface of the inner pipe 4. The inner pipe 4 is made of a material having relatively high rigidity, and the outer pipe 5 is made of a relatively flexible material. The catheter body 2 is composed of a base portion 6, an intermediate portion 7 and a distal end portion 8 in order from the base end 21 side. Of these, the base portion 6 and the intermediate portion 7 have the double pipe structure, and the tip portion 8 is composed of only the outer pipe 5.

At the base 6, the outer diameter of the catheter body 2 is substantially constant in the catheter longitudinal direction. In addition, the inner diameter of the catheter body 2 (diameter of the lumen 3) is also preferably substantially constant.

In the intermediate portion 7, the outer diameter of the catheter body 2 gradually decreases in the direction of the tip 22 (hereinafter referred to as the tip direction). Further, in the intermediate portion 7, it is preferable that the outer diameter of the inner tube 4 is gradually reduced toward the distal end, and further, the inner diameter of the catheter body 2 is preferably substantially constant in the longitudinal direction. As a result, the thickness of the inner tube 4 gradually decreases toward the distal end, and its rigidity continuously decreases.

The tip portion 8 lacks the inner tube 4 and is composed only of the outer tube 5. At the tip portion 8, the outer diameter of the catheter body 2 gradually decreases in the tip direction. The thickness of the outer tube 5 at the distal end 8 may be substantially constant in the catheter longitudinal direction as shown in the figure,
In order to improve the insertability of the guide wire by making the diameter of the lumen 3 constant or reducing the diameter thereof, it is preferable that the thickness of the entire outer tube 5 or a part thereof gradually decreases in the distal direction. It should be noted that such a configuration is also advantageous in continuously reducing the rigidity of the tip portion 8 in the tip direction,
It is also preferable for improving the followability and safety.

The catheter body 2 in the intermediate portion 7
The taper angle of the outer surface and the taper angle of the outer surface of the catheter body 2 at the distal end 8 may be the same as shown in FIG. 2 or may be different. At the boundary portion 9 between the base portion 6 and the intermediate portion 7, the outer surface of the catheter body 2 forms a continuous smooth surface (for example, a surface curved in the catheter longitudinal direction), and a step is formed substantially. Not not. As a result, there is little irritation to the blood vessel during insertion of the catheter, damage to the inner wall of the blood vessel is prevented, and furthermore, the interface 9 is worn when passing through the insertion port of a catheter insertion device such as a sheath, and the boundary portion 9 is worn. To be prevented.

A boundary portion 10 between the intermediate portion 7 and the tip portion 8 is also provided.
In the same manner, since the outer surface of the catheter body 2 forms a continuous surface and no step is formed, the same effect as described above can be obtained. When the taper angle of the outer surface of the catheter body 2 at the intermediate portion 7 and the taper angle of the outer surface of the catheter body 2 at the tip portion 8 are different, the outer surface of the catheter body 2 at the boundary portion 10 is Like the boundary portion 9, it is preferable to form a continuous smooth surface.

As the constituent material of the inner tube 4, for example, polyolefin such as polypropylene and polyethylene, polyester such as polyamide, polyethylene terephthalate and polybutylene terephthalate, polyurethane, polyvinyl chloride, polystyrene resin, ethylene-tetrafluoroethylene copolymerization Fluorine-based resins such as coalesce, resins having various flexibility such as polyimide, and various elastomers such as polyamide elastomer, polyester elastomer, and polyurethane elastomer can be used. Among them, polyamide elastomer or polyester elastomer is preferable, Polyamide elastomer is more preferred. By using such a material, an optimum bending elastic modulus for the inner tube 4 can be obtained, and the solvent resistance is high and the kink resistance is excellent. Further, since the polyamide elastomer and the polyester elastomer have relatively high rigidity near room temperature, they are excellent in pushability and torque transmission, and they are flexible near body temperature, so they are better adapted to the bending of blood vessels after being inserted into the body, Followability and kink resistance are further enhanced.

Here, the polyamide elastomer means, for example, nylon 6, nylon 64, nylon 66, nylon 610, nylon 612, nylon 46, nylon 9, na nylon 11, nylon 12, N-alkoxymethyl modified nylon, hexamethylene diamine. -Typical block copolymers having various aliphatic or aromatic polyamides such as isophthalic acid polycondensate and metaxyloyldiamine-adipic acid polycondensate as a hard segment and a polymer such as polyester or polyether as a soft segment. In addition, a polymer alloy (polymer blend, graft polymerization, random polymerization, etc.) of the polyamide and a highly flexible resin, a softening agent of the polyamide with a plasticizer, etc., and a mixture thereof It is a concept that also includes.

As the plasticizer, it is preferable to use one that is difficult to extract with a solvent or blood. Further, the polyester elastomer is typically a block copolymer of a saturated polyester such as polyethylene terephthalate or polybutylene terephthalate, and a polyether or polyester, and other than these, a polymer alloy or the saturated polyester is used as a plasticizer or the like. It is a concept that includes softened materials and mixtures thereof.

If necessary, the polyamide elastomer or polyester elastomer may be mixed with various additives such as alloying agents, compatibilizing agents, curing agents, softening agents, contrast agents, stabilizers and coloring agents. Good. In this case, it is preferable to use an additive component that is difficult to be extracted with a solvent, a drug solution, blood or the like. Moreover, the material of the inner tube 4 is usually the same along the longitudinal direction thereof, but the composition may be different depending on the site, if necessary.

As the constituent material of the outer tube 5, for example, polypropylene, polyethylene (particularly low-density polyethylene), polyolefin such as ethylene-vinyl acetate copolymer, the polyamide elastomer, the polyester elastomer, polyurethane elastomer, and soft polychlorinated material. Various flexible resins and elastomers such as vinyl, polystyrene elastomer, fluorine-based elastomer, silicone rubber, and latex rubber can be used. Among them, the polyamide elastomer or polyester elastomer is preferable for the same reason as above. A polyester elastomer is more preferable.

The material of the outer tube 5 is usually the same along the longitudinal direction, but the composition may be different depending on the part, if necessary. Generally, the bending rigidity of an object is represented by the product of the bending elastic modulus E and the moment of inertia of area I. The second moment of area I of the catheter body, which is a cylindrical tubular body, is determined from the outer diameter D _o and the inner diameter D _i ,
It is expressed by the following formula 1.

[0042]

[Equation 1]

[0043] That is, larger the outer diameter D _o is large, when the outside diameter D _o is constant, rigidity increases as the difference between the outer diameter D _o and the inner diameter D _i is greater. In the case of a blood vessel catheter, the outer diameter and the inner diameter of the catheter body 2 are often regulated by the applied vascular system and the procedure, and the difference between the outer diameter and the inner diameter tends to decrease empirically. Is low, which is disadvantageous for preventing bending. Therefore, to obtain the necessary and sufficient rigidity,
It is preferable to select the material based on the flexural modulus of the material.

In the present invention, the rigidity of the base portion 6 and the intermediate portion 7 mainly affects the pushability and the torque transmissibility, and most of them depend on the rigidity of the inner pipe 4. Further, the rigidity of the distal end portion 8 mainly affects the followability and the abutment resistance (particularly, the pressure on the bent blood vessel), and is equal to the rigidity of the outer tube 5. Then, the balance between the rigidity of the inner tube 4 and the rigidity of the outer tube 5 largely affects the kink resistance. For this reason, it is necessary to set the bending rigidity of the inner pipe 4 and the outer pipe 5 to appropriate values, and specifically, the following ranges are preferable.

Flexural Modulus of Inner Tube 4 (ASTM D-79
(0, 23 ° C.) is preferably 1500 to 15000 kg / cm ² , and more preferably 2000 to 8000 kg / cm ² . If it is less than 1500 kg / cm ² , pushability and torque transmission will be poor, and if it exceeds 15000 kg / cm ² , followability to the guide wire will be poor, and the load on the flexible inner wall of the blood vessel will increase, and the tip The rigidity difference from the portion 8 becomes large, and a kink easily occurs at the boundary portion 10.

The flexural modulus (ASTM D-790, 23 ° C.) of the outer tube 5, especially the outer tube 5 at the tip portion 8 is 5 to 1
500 kg / cm ² is preferred, 300-800 kg / c
More preferably m ² . If this is less than 5 kg / cm ² , it becomes difficult for the pushing force and torque from the base 6 to be transmitted to the vicinity of the tip 22, and the rigidity difference between the intermediate portion 7 and the tip 8 becomes large, and at the boundary portion 10. Kink is likely to occur, and if it exceeds 1500 kg / cm ² , followability with respect to the guide wire is deteriorated and irritation given to the inner wall of the blood vessel is increased.

In addition, the flexural modulus of the inner tube 4 and the outer tube 5 (A
STM D-790, 23 ° C) difference is 100-140
It is preferably about 00 kg / cm ² , and is 100 to 6000.
More preferably, it is about kg / cm ² . In the present specification, the bending elastic modulus of the inner pipe or the outer pipe refers to the bending elastic modulus of the material forming the inner pipe or the outer pipe. In the present invention, the inner pipe 4 and the outer pipe 5 are joined by bringing the outer peripheral surface of the inner pipe 4 and the inner peripheral surface of the outer pipe 5 into close contact with each other. A method of adhering the tube 5 with an adhesive or a solvent, a method of fusion-bonding the inner tube 4 and the outer tube 5 (for example, heat fusion, high-frequency fusion), and a method of expanding the outer tube 5 with a solvent to form the inner tube 4 Or the inner tube 4 and the outer tube 5
An example is a method of integrally forming by color extrusion molding.

In the present invention, the size of the catheter body 2 is not particularly limited. For example, in the case of a blood vessel catheter used by inserting it into a cerebral blood vessel, the total length of the catheter body 2 is about 50 to 200 cm, particularly 70 to 150 cm. The length of the intermediate portion 7 is preferably about 5 to 30 cm, especially 10
~ 20 cm is preferable, the length of the tip 8 is 7 ~ 35
It is preferably about cm, particularly about 10 to 20 cm. In such a range, the bending rigidity of each part of the catheter body 2 is well balanced, and the above-mentioned effects are effectively exhibited.
From the same viewpoint, it is preferable that the other dimensions of the base portion 6, the intermediate portion 7 and the tip portion 8 are within the ranges shown in Table 1 below.

[0049]

[Table 1]

In the present invention, the outer surface of the catheter body 2 is preferably covered with a hydrophilic (or water-soluble) polymer substance (not shown). As a result, when the outer surface of the catheter body 2 comes into contact with blood, physiological saline or the like, the friction coefficient is reduced and lubricity is imparted, and the slidability of the catheter body 2 is further improved. Property, followability, kink resistance and safety are further enhanced.
Examples of the hydrophilic polymer substance include the following natural or synthetic polymer substances or derivatives thereof.

<Natural polymer substances> 1) Starch-based example: Carboxymethyl starch, dialdehyde starch 2) Cellulose-based example: CMC, MC, HEC, HPC 3) Tannin, nignin type Example: Tannin, nignin 4) Polysaccharide System example: alginic acid, gum arabic, guar gum, tragacanth gum, tamarind species 5) Protein example: gelatin, casein, glue, collagen

<Synthetic water-soluble polymer> 1) PVA type Example: polyvinyl alcohol 2) Polyethylene oxide type Example: Polyethylene oxide, polyethylene glycol 3) Acrylic acid type Example: Sodium polyacrylate 4) Maleic anhydride type Example: Methyl Vinyl ether maleic anhydride copolymer 5) Phthalic acid type Example: Polyhydroxyethyl phthalic acid ester 6) Water-soluble polyester Example: Polydimethyl roll propionic acid ester 7) Ketone aldehyde resin Example: Methyl isopropyl ketone formaldehyde resin 8) Acrylamide type example : Polyacrylamide 9) Polyvinylpyrrolidone type Example: PVP 10) Polyamine type Example: Polyethyleneimine 11) Polyelectrolyte Example: Polystyrene sulfonate 12) Others Example: Water-soluble nylon

Among these, in particular, a cellulosic polymer material (for example, hydroxypropyl cellulose),
Polyethylene oxide-based polymer (polyethylene glycol), maleic anhydride-based polymer (eg, maleic anhydride copolymer such as methyl vinyl ether maleic anhydride copolymer), acrylamide-based polymer (eg, polyacrylamide) ) And water-soluble nylon (for example, AQ-nylon P-70 manufactured by Toray Industries, Inc.) are preferable because a low coefficient of friction can be stably obtained. Further, the derivative of the polymer substance is not limited to a water-soluble derivative, and as long as the water-soluble polymer substance is a basic constituent, there is no particular limitation, and even if it is insolubilized, the molecular chain is Anything can be used as long as it has a degree of freedom and contains water.

For example, esterification products, salts, amidation products, anhydrides, halides, etherification products, hydrolysates, acetalization products, formalization products obtained by condensation, addition, substitution, oxidation, reduction reactions of the above-mentioned polymer substances. , Alkylol compound, quaternary compound, diazo compound, hydrazide compound, sulfonate compound, nitrate compound, ion complex; diazonium group, azido group, isocyanate group, acid chloride group, acid anhydride group, iminocarbonic acid ester group, amino group, Carboxyl group, epoxy group, hydroxyl group, arhydride group, etc.
Crosslinked products with substances having two or more reactive functional groups; vinyl compounds, acrylic acid, methacrylic acid, diene compounds,
Examples thereof include copolymers with maleic anhydride and the like.

In order to fix such a coating layer of a hydrophilic polymer substance on the outer surface of the catheter body 2, it is shared with the reactive functional group existing in or introduced into the outer tube 5 or on the surface of the outer tube 5. It is preferably carried out by binding. This can provide a continuous lubricious surface. The reactive functional group existing in or introduced into the outer tube 5 or on the surface thereof may be any one as long as it reacts with the above-mentioned polymer substance and bonds or crosslinks to fix it, and a diazonium group, an azide group, an isocyanate. Group, acid chloride group, acid anhydride group, iminocarbonic acid ester group, amino group, carboxyl group, epoxy group, hydroxyl group, aldehyde group and the like, particularly isocyanate group, amino group, aldehyde group,
Epoxy groups are preferred.

The average molecular weight of the hydrophilic polymer in the present invention is not particularly limited, but it is preferably about 3 to 5,000,000. As a result, a lubricating layer having high lubricity, an appropriate thickness, and an appropriate degree of swelling when containing water can be obtained. The thickness of the lubricating layer made of such a hydrophilic polymer is not particularly limited, but is about 0.1 to 100 μm, particularly 1
It is preferably about 30 μm. The composition and coating method of the hydrophilic polymer substance in the present invention are described in, for example, JP-A-53-106778 and US Pat. No. 410.
0309, JP-A-60-259269, Japanese Patent Publication No. 1-
Those described in No. 33181 can be applied.

[0057]

EXAMPLES Specific examples of the present invention will be described below. (Example) Polypropylene oxide and nylon 610
A molded body of the inner tube 4 is manufactured by using a polyamide elastomer that is a copolymer of the above, and a molded body of the outer tube 5 is manufactured by using a polyester elastomer that is a copolymer of polytetramethylene oxide and polybutylene terephthalate. The inner tube 4 was inserted into the outer tube 5 and they were fused together to produce the catheter body 2 having the structure shown in FIG.

The flexural modulus of the inner tube 4 (ASTM
D-790, 23 ° C.) is 5000 kg / cm ² , and the flexural modulus of the outer tube 5 (ASTM D-790, 23 ° C.)
Was 720 kg / cm ² . Next, Japanese Patent Publication 1-333181
By forming a coating layer of methyl vinyl ether maleic anhydride copolymer, which is a hydrophilic polymer, on almost the entire outer surface of the catheter body 2 by the method described in
Then, the hub 11 was attached to the proximal end 21 of the catheter body to obtain the angiocatheter of the present invention.

The dimensions of each part of the catheter body 2 are as follows.
It is as follows. Total length of catheter body: 150 cm Base length: 110 cm Base outer diameter: 1.1 mm Base inner diameter: 0.65 mm Intermediate length: 20 cm Intermediate outer diameter: Gradually reduced from 1.1 mm to 0.90 mm Intermediate inner diameter: 0.65 mm Tip Length: 20 cm Tip outer diameter: Gradually reduced from 0.90 mm to 0.74 mm Tip inner diameter: Gradually reduced from 0.65 mm to 0.54 mm

(Comparative Example) Polypropylene inner tube 14
3 on the other hand, on the other hand, a molded body of the outer tube 15 is manufactured from an ethylene-vinyl acetate copolymer, the inner tube 14 is inserted into the outer tube 15, and these are fusion-bonded to each other. A catheter body 12 having a double tube as the base portion 16 and an outer tube 5 as the tip portion 18 as shown in FIG. The catheter body 12 does not have a portion corresponding to the intermediate portion. Next, a hub 11 similar to that of the above-described embodiment was attached to the proximal end of the catheter body 12 to obtain a vascular catheter 1'of a comparative example.

The dimensions of each part of the catheter body 12 are as follows. Total length of catheter body: 146 cm Base length: 128 cm Base outer diameter: 0.94 mm Base inner diameter: 0.61 mm Tip length: 18 cm Tip outer diameter: 0.74 mm Tip outer diameter: 0.54 mm

[Experiment 1] The following bending tests were conducted on the blood vessel catheters of the above-mentioned Examples and Comparative Examples in order to investigate the kink resistance. In the cylindrical fixing device, the catheter body is inserted and fixed up to a position of about half the length of the intermediate portion, while it is fixed in the lumen of the catheter body.
Insert the wire from the tip side of the catheter body to a position about half the length of the tip, and in water at 37 ° C, make the base end draw an arc around the tip (inside the lumen) of the wire. Angle θ formed by the axis of the base and the axis of the tip when the creases are formed at the boundary between the middle part and the tip by gradually moving
Was measured (5 times of measurement).

As a result, in the blood vessel catheter of the above-described embodiment of the present invention, θ = 71.0 °, whereas in the blood vessel catheter of the above-mentioned comparative example, θ = 64.1 °. It was confirmed that the catheter has excellent kink resistance.

[Experiment 2] Using the vascular catheters of the above-mentioned Examples and Comparative Examples, the following animal experiments were conducted to examine the operability of the vascular catheters. With the guide wire inserted through the lumen of the catheter, the catheter body was inserted from the carotid artery of the rabbit, and its tip was introduced through the abdominal aorta to the distal part of the mesenteric artery. At the bifurcation of the blood vessel, a blood vessel was selected by appropriately advancing and retracting the guide wire, advancing and retracting the catheter, and rotating.

In the blood vessel catheter of the above-mentioned embodiment of the present invention, the friction with the blood vessel is small, the pushability and the torque transmission property at the time of rotation are very good, and the blood vessel selectivity at the bifurcation and the followability to the guide wire are also excellent. Good,
In particular, such an effect was exhibited even in small-diameter peripheral blood vessels. For this reason, the operation of inserting the catheter was easy, and the time required for the tip of the catheter to reach the target site was short (about 5 minutes).

On the other hand, the angiocatheter of the above comparative example has problems in pushability and torque transmissibility, it takes a lot of time to select the blood vessel at the bifurcation, and the followability to the guide wire is poor. Such defects were remarkable in peripheral blood vessels. Therefore, the operation of inserting the catheter was difficult, and the time required for the tip of the catheter to reach the target site was longer than that of the present invention (about 15 minutes).

[0067]

As described above, according to the blood vessel catheter of the present invention, the main part of the catheter body is a double tube in which an inner tube having high rigidity and an outer tube having lower rigidity are combined. This double-tube portion is composed of a base portion in which the outer diameter of the catheter body is substantially constant in the longitudinal direction, and an intermediate portion in which the outer diameter of the catheter body gradually decreases toward the distal end. Since the tip part on the tip side of the middle part is composed of a flexible outer tube whose outer diameter gradually decreases,
Pushability, torque transmission, followability for guidewires inserted into bent blood vessels, kink resistance, selectivity at vessel bifurcation are improved, and there is little irritation to blood vessels, preventing damage to the inner wall of blood vessels. , High safety.

When the outer surface of the catheter body is covered with a hydrophilic polymer substance, a lubricous surface is formed by contact with blood or the like, and frictional resistance is reduced, so that the above effect is further enhanced. Such an effect of the present invention can be obtained not only in ordinary arteries and veins having a relatively large diameter, but also in vessels having a small diameter and a large number of branches, such as cerebral blood vessels and other peripheral blood vessels, which bend and meander. It is also effective when selectively inserted.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration example of a blood vessel catheter of the present invention.

FIG. 2 is a vertical cross-sectional view schematically showing an enlarged configuration of the vicinity of the distal end portion of the blood vessel catheter shown in FIG.

FIG. 3 is a vertical cross-sectional view schematically showing an enlarged configuration of the vicinity of the distal end portion of the blood vessel catheter of the comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vascular catheter (present invention) 1'vascular catheter (comparative example) 2 Catheter body 21 Base end 22 Tip 3 Lumen 4 Inner tube 5 Outer tube 6 Base part 7 Intermediate part 8 Tip part 9, 10 Boundary part 11 Hub 12 Catheter body 14 Inner Tube 15 Outer Tube 16 Base 18 Tip

Claims (8)

[Claims] 1. A double-tube structure comprising an inner tube and an outer tube that adheres to the outer surface of the inner tube, the catheter body having a lumen formed inside from the proximal end to the distal end. Is a blood vessel catheter having a bending elastic modulus greater than that of the outer tube, wherein the catheter body has a base portion having an outer diameter substantially constant in the longitudinal direction, the base portion including the inner tube and the outer tube, and a tip of the base portion. From the inner tube and the outer tube, the intermediate portion extending from the inner tube to the distal end of the catheter body, and the outer diameter of which gradually decreases toward the distal end of the catheter body; And an outer diameter of the outer tube is gradually reduced toward the distal end, the bending rigidity of the catheter body gradually decreases from the intermediate portion to the distal portion, and the base portion and the intermediate portion. When Vascular catheters, characterized in that in the vicinity of the boundary portion between the tip and the boundary and near the middle portion forms a smooth surface where the outer surface of each catheter body is continuous. 2. The vascular catheter according to claim 1, wherein the outer diameter of the inner tube in the intermediate portion gradually decreases in the distal direction. 3. The blood vessel catheter according to claim 1, wherein the thickness of the outer tube at the tip portion gradually decreases in the tip direction. 4. The flexural modulus of the inner tube (ASTM D-
790, 23 ° C.) is 1500-15000 kg / cm ² ; 5. The vascular catheter according to claim 1, wherein the inner tube is made of a polyamide elastomer. 6. The bending elastic modulus (ASTM D-790, 23 ° C.) of the outer tube at the tip portion is 5 to 1500 kg.
The blood vessel catheter according to any one of claims 1 to 5, which is / cm ² . 7. The blood vessel catheter according to claim 1, wherein the outer tube is made of a polyester elastomer. 8. The vascular catheter according to claim 1, wherein an outer surface of the catheter body is covered with a hydrophilic polymer substance.