JP2004081883A - Catheter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-quality catheter with a laminated tube wall structure having a flexible resin layer and a rigid resin layer, whose principal tube is made of a flexible ultra-fine tube, with its inside and outside diameters being uniform throughout its length, which is suitable for medical treatment conditions in that both the compatibility of the flexibility and the rigidity of the principal tube and the fine adjustability in required mechanical properties are improved. <P>SOLUTION: The principal tube of this catheter comprises three layers; a rigid resin tube and a flexible resin tube, which form a gradually-varying laminated tube, and a lining tube applied to the inner surface thereof. The lining tube that is drawn is made different in hardness, by thermal treatment, along the longitudinal direction. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a catheter used for injecting an angiographic agent by inserting it into a blood vessel, or for inserting a therapeutic balloon body into a stenotic lesion of a blood vessel, and more particularly, to a meandering like cerebral blood vessel. The present invention relates to a micro-shaped catheter suitable for insertion into a capillary.

The catheter is made of a flexible, ultra-thin, large-sized resin tube that can be inserted into a blood vessel.The distal end of the catheter is guided into the blood vessel of the patient and then out of the body. It is introduced into a blood vessel that is bent into a multi-branch and the tip is set at the affected part, and it is used as a contrast agent catheter for injecting a contrast agent into the catheter in the set state, or the catheter in the set state is used as a guide tube. It is used as a guiding catheter to insert a balloon catheter.

In order to smoothly insert the above catheter into a blood vessel and accurately set the distal end portion at a predetermined position, it is necessary to adjust the elasticity and rigidity in harmony, the vertical load resistance against insertion resistance (buckling resistance), and the A highly flexible tip that can be inserted into a capillary vessel without damaging the vessel wall, as high mechanical properties that satisfy "torsional rigidity and steering characteristics" that can properly adapt to end insertion and rotation operations are required. Therefore, a form of “flexible frontward / rearward rigidity” in which the rigidity gradually increases in the direction of the rear end operated outside the body is desired.

In view of the above-mentioned required mechanical properties, Patent Document 1 discloses that the entire length of the elongated tubular body is set to “a two-layered tubular structure of an outer layered tube made of a soft resin and an inner layered tube made of a hard resin”. The thickness of the inner layer pipe is reduced in the direction from the front end to the rear end, and the thickness of the inner layer pipe is increased from the front end to the rear end. There is a catheter having a structure in which the rigidity is gradually increased toward the rear end.

Japanese Patent Publication No. 2-30265

The above catheter is inevitable for the patient to insert a long tubular body other than the proximal end to the outside of the body into the blood vessel, and the outside diameter of the tube is as small as possible within a range that does not inhibit smooth treatment On the other hand, for example, in the case of delivering a contrast medium into a blood vessel, if the required amount is delivered within a short time, the burden on the patient is reduced, and the treatment of the contrast medium is made faster and more efficient. In order to smoothly and easily insert the vascular stenosis treatment balloon into the affected area, the inner diameter of the catheter is preferably as large as possible, which satisfies the above conflicting technical requirements. Is preferably as thin as possible, for example on the order of microns, and this thinning of the tube wall is a technical task imposed on the catheter, and the conventional structure should be improved from this viewpoint. In room That.

On the other hand, in the case of the two-layer pipe structure, the pipe cross section is “the inner layer near the center of the pipe is a hard layer, and the outer layer away from the center of the pipe is a soft layer”, and the contribution of the pipe rigidity (particularly torsional rigidity) is large. Since the outer peripheral portion of the tube is a hard / soft combination of a soft layer, the above-mentioned requirement for the thinnest wall of the tube results in insufficient rigidity. It is poor in leading insertability into a thin tube having a large degree of chipping, bending and meandering.

Further, conventional catheters are commonly formed into a uniform structure intended for the necessary mechanical properties, and the complexity of the blood vessel path, the size of the blood vessel, and the stenosis of the blood vessel, which vary subtly for each individual body. However, there is a difficulty in selecting products having a quality that matches the blood vessel conditions such as the degree of blood vessel sclerosis and the like. The present invention solves the above-mentioned drawbacks of the prior art and provides a catheter of higher quality.

The present invention to solve the above technical problem is a catheter having a laminated thin-walled structure of a soft resin layer and a hard resin layer, and a catheter made of a main body of a flexible elongated tube having a uniform inner and outer diameter having a uniform length. The outer tube of the layer and the inner tube of the soft resin layer, and the thickness of the inner tube is a two-layer wall tube in which the front end of the main tube is thick and the rear end is thin, At the front end of the main tube, a catheter of the first invention comprising a structure in which a flexible leading portion of a short tube made of only the soft resin layer is integrally connected to form a series of tubes.

"In a catheter having a laminated tube wall structure of a soft resin layer and a hard resin layer and a main tube of a flexible ultrafine tube having a uniform inner and outer diameter, the outer tube of the hard resin layer and the inner layer of the soft resin layer A three-layer wall composed of a pipe and a lining pipe made of a hard resin material inscribed in the inner pipe, and the thickness of the inner pipe is such that the front end of the main pipe is thick and the rear end is thin. Further, at the front end of the main tube, the catheter of the second invention comprising a structure in which a flexible leading portion of a short tube made of only the soft resin layer is integrally connected to form a series of tubes, ''

"A laminated tube wall structure of a soft resin layer and a hard resin layer is formed, and the entire length is made of a main tube of a flexible elongated tube having a uniform inner and outer diameter, and the soft resin layer is formed at a front end to a rear end of the main tube. The thickness of the catheter is reduced in the direction of the portion, and a front end of the main tube, a soft leading portion of a short small tube made of only a soft resin layer is integrally connected to form a series of tubes. Consisting of the catheter of the three inventions.

That is, the catheter of the present invention having the above-described structure is a catheter comprising a main tube in which the thickness of the soft resin layer is reduced from the front end to the rear end of the tube by forming a laminated tube wall of a soft resin layer and a hard resin layer. A common structural feature is a unique configuration in which a "flexible leading portion consisting of only a soft resin layer" is continuously provided at the front end of the tube to improve leading insertion into a blood vessel and pulling out from a blood vessel.

The catheter according to the first and second aspects of the present invention is based on the structural characteristics of the outer tube of the hard resin layer and the soft resin, with the intention of “the outer diameter of the main tube is made smaller, and the inner diameter is made larger”. It is possible to provide a catheter of various qualities that is adapted to different vascular conditions for each human body by variously adjusting and setting the structure (first invention) of the tube wall form of the inner layer tube and the mechanical properties of the main tube. For this purpose, a three-layer tube wall structure (second invention) in which a lining tube made of a hard resin material is provided inside the laminated structure of the first invention.

The flexible leading portion having the common configuration of the present invention further improves the flexibility and adhesion of a lubricant / antithrombotic agent for improving the ability to insert into a blood vessel, and improves the connectivity with the main tube. For the purpose, a mode of adopting a structure of “a part of the whole or outer periphery is a fine foamed resin layer” or a mode of forming a joint portion with a main pipe “taper surface joining with a large joining area” is adopted. Then, the lining tube of the second invention is formed into an independent tube by a known stretching process and subjected to a heat treatment to form a continuous form of zones in which soft hardness continues in the longitudinal direction, or a “thin portion” in the longitudinal direction. A mode in which the technical intention is further improved by adopting a thickness variation mode in which “tapered portion / thick portion” exists is adopted. It should be noted that the present invention having the above-described configuration includes a higher concept invention and peripheral inventions of the invention described in the claims, and the inventions of the claims are shown in FIGS.

In the catheter of the present invention having the above-mentioned flexible leading portion, the flexible leading portion consisting of only the soft resin layer can deform and adapt to the bending / meandering path of the blood vessel to advance or retreat, so that it bends in a complicated manner and meanders. Even in the case of a capillary blood vessel, it can be easily advanced and inserted without damaging the blood vessel wall, and can be easily pulled out. In the case of the layer made of the fine foamed resin layer of the above-described embodiment, since a fine recessed group formed by the fine foamed group is present on the surface, a lubricant (hydrophilic polymer) applied to the outer periphery for improving the intravascular insertion property and an antithrombotic The adhesion and retention of the agent (heparin) is improved, the blood vessel insertability is satisfactorily and stably maintained, and the anticoagulant effect is improved. Then, the adhesive agent and the soft resin on the main tube side during heat fusion enter and solidify due to the minute concave group, so the connection performance with the main tube is further improved and stabilized, and the risk of detachment and separation in the blood vessel is prevented it can. And the operability of insertion into a thin tube is improved by the weight reduction by the foamed form.

Furthermore, since the flexible leading portion is provided, the breaking strength of the distal end portion of the catheter is improved, and the risk that the distal end portion breaks and separates and remains in the blood vessel when the catheter is pulled out from the bent thin tube having a large resistance can be prevented. That is, when a tensile load is generated at the distal end portion of the main pipe of the hard and soft two layers, the tensile load is carried only by the hard resin layer inferior in elastic elongation. The breaking strength decreases in proportion to the decrease in wall thickness. Therefore, there is a possibility that the leading end portion of the main pipe breaks and separates in a thin pipe having a large resistance when the main pipe has no flexible leading portion. However, since the flexible leading portion of the catheter of the present invention is only a soft resin layer in the absence of a hard resin, the tensile strength per unit is low, but a thick soft resin layer corresponding to the thickness of the conventional hard and soft two layers. Is easily elastically extended and bears a large tensile load, so that the breaking strength is large and there is no risk of separation and remaining in the blood vessel.

In the catheter according to the first aspect of the invention, the main tube has a “hard outer layer tube and a soft layer inner layer tube configuration”, and the contribution of the torsion / bending rigidity of the main tube of the elongated tube becomes large. Since the pipe wall moving away from the center is hard, the outer diameter of the main pipe is the same when the rigidity of the main pipe is the same as that of the above-mentioned known example of the outer layer of the soft layer and the inner layer of the hard layer. It is possible to make the diameter smaller and the inner diameter of the main pipe larger. That is, since the hard layer that controls the bending stiffness and torsional characteristics of the main pipe is farther from the bending neutral plane and the center of torsion, the second moment of area and the second moment of cross section of the hard layer having the bending and torsional rigidity coefficient of the main pipe Is larger than that of the conventional structure.

In the catheter of the second invention, the main tube has a three-layer structure of an outer layer tube of a hard layer, an inner layer tube of a soft layer, and a lining tube of a hard tube inside the inner layer tube. The main factor that governs is the two elements of the outer layer pipe and the lining pipe, and the combination of the two elements by the change in wall thickness and hardness improves the degree of freedom in controlling the rigidity in the longitudinal direction of the main pipe, and the three layers Since the pipe structure is a `` side-switch type with both sides hard and intermediate soft, '' the outer pipe and lining pipe with hard sides on both sides have a degree of freedom of relative deformation with respect to the intermediate soft inner pipe, so the main pipe Flexibility and rigidity can coexist easily.

Therefore, on the basis of securing the appropriate flexibility, the main pipe having necessary and sufficient rigidity is configured to stably secure "steering properties such as torque transmission force and rotation responsiveness", By finely adjusting and setting the necessary mechanical properties, it becomes possible to form a catheter of various qualities that matches the conditions of the blood vessel to be treated (the state of the blood vessel path, the size of the blood vessel, the degree of blood vessel stenosis, the degree of blood vessel sclerosis, etc.).

From the above effects, the catheter of the present invention is provided with a flexible leading portion made of a soft resin layer, so that the catheter has good insertability and withdrawal into a capillary blood vessel having a large degree of bending and meandering, and improves the vascular treatment property by the catheter. I do.

And the catheter of the first invention is capable of "smaller outer diameter and larger inner diameter" on the basis of the required mechanical properties such as flexibility, torsional rigidity, and steering properties as a microtubular body. The catheter according to the second aspect of the present invention adjusts and sets necessary mechanical properties to provide a high-quality catheter matched to the vascular condition of an individual patient. Improve and improve the performance. There are the above effects.

Hereinafter, a preferred embodiment based on the basic mode will be described.

First, a catheter 1 according to one embodiment of the first and third inventions will be described with reference to FIG. That is, in the catheter 1 composed of the main tube 2 of a flexible elongated tube having a two-layer tube wall structure of a hard resin layer and a soft resin layer, the catheter of this embodiment has an outer tube 6 of a hard resin layer and a soft resin layer. The inner tube 5 has a uniform outer diameter D1 and a uniform inner diameter D2. The inner tube 5 has a thickness from the maximum thickness T1 of the front end portion 7 to the minimum thickness of the rear end portion 8. The main pipe 2 is a flexible pipe whose rigidity gradually increases in the direction from the front end to the rear end in a substantially tapered shape having a thickness T2.

At the front end of the main tube 2, a flexible leading portion 3 of a short tube made of only the same soft resin layer as the inner tube 5 and having the same outer diameter D 1 and inner diameter D 2 as the main tube 2 is integrally connected. The flexible leading portion 3 functions as a leading guide portion for insertion into a blood vessel. In the catheter 1 of the embodiment shown in FIG. 1, the outer tube 6 is made of polyamide and the flexural modulus is 5920 kgf / sq.cm. The inner tube 5 is made of polyurethane and the flexural modulus is 700 kgf / sq.cm. Bending elastic modulus = 700 kgf per square centimeter, outer diameter D1 = 0.92 mm, inner diameter D2 = 0.6 mm, length of main pipe 2 = 1000 to 1300 mm, length of flexible leading portion 3 = 50 to 130 The breaking strength of the distal end portion of the main pipe 2 is about 0.8 kgf, and the breaking strength of the flexible leading section 3 is about 1.0 kgf. The thickness of the inner tube 5 may be changed stepwise from T1 to T2 in addition to the tapered shape shown. The catheter of FIG. 1 has the above-described operation.

Next, the catheter 1 according to one embodiment of the second invention and the third invention will be described with reference to FIG. That is, the inner tube 5 is composed of the outer layer tube 6 of the hard resin layer and the inner layer tube 5 of the soft resin layer similar to the embodiment of FIG. The main tube 2 of the embodiment shown in FIG. 2 is provided inside the inner tube 5 in the case where the main tube 2 of the embodiment shown in FIG. A lining tube 4 of a uniform thickness made of a hard resin material is integrally provided, and the main tube 2 has a cross-sectional structure of “a sandwich type in which a soft layer is sandwiched between hard layers”.

The catheter 1 shown in FIG. 2 described above has the mechanical strength in the longitudinal direction of the main tube 2 on the basis of securing the necessary flexibility by the combination of the setting of the hardness and softness of the three layers and the change in the thickness of each layer. The properties are adjusted in various ways, and the flexibility and rigidity in the longitudinal direction are intentionally changed, such as a form in which the radius of curvature gradually increases and decreases to R1, R2,... It can be formed into a catheter 1 of various quality adjusted. The lining tube 4 in FIG. 2 is made of a fluororesin (PFA / PTFE) material.

Next, another embodiment of the main pipe 2 in the form of a three-layer pipe having the lining pipe 4 will be described with reference to FIGS. First, in FIG. 3 (A), the lining tube 4 is formed by a known stretching method and partially softened and heat-treated. The middle 1/3 length is weakly softened zone Y. The approximately 1/3 length on the rear end side is hard zone Z unique to the material. It is divided into three in the length direction, and "hardness" is stepped from the front end to the rear end. It has a form that is gradually increased. On the other hand, in the case of FIG. 3B, the lining tube 4 has a tapered shape in which the wall thickness gradually changes in the direction of the rear end portion 8 by making the minimum thickness T3 at the front end portion 7, A 1/3 length (a zone corresponding to the hard zone Z) has a uniform thickness of the maximum thickness T4, which is similar to the three-zone configuration shown in FIG.

カ テ ー テ ル In addition, the catheter 1 having the lining tube 4 having the gradually deformed thickness shown in FIG. 3B is formed by the following method. That is, a lining tube having a uniform thickness of the maximum thickness T4 is extruded on a cored bar, and then the outer periphery of the lining tube on the cored bar is ground and polished to form the lining tube having the tapered outer peripheral shape. Forming into 4 Thereafter, the core metal with the lining tube 4 is used as a core metal for extrusion molding of the “laminated tube of the inner tube 5 and the outer tube 6”, and the inner tube 5 and the outer tube are placed on the lining tube 4 with the core metal. 6 is laminated and then the core metal is pulled out and separated to form the catheter 1 shown in FIG. 3 (B).

The above-described catheter 1 of the embodiment shown in FIGS. 2 and 3 has the above-described action, and by changing the mechanical properties to various quality, the blood vessel size and the meandering state of the blood vessel in the blood vessel condition to be treated are obtained. -A catheter of various qualities is preformed and standardized in accordance with the degree of stenosis of the blood vessel, the degree of sclerosis of the blood vessel, etc., and further improvement of vascular treatment by the catheter can be promoted. Since the outer tube 6 is made of a hard resin layer, the main tube 2 of the embodiment shown in FIGS. 1 to 3 has a specific function of improving the imaging effect of the catheter. That is, when the contrast agent is added to the resin material, the resin material has a qualitative property of being hardened. Therefore, in the case of a two-layer hard / soft resin tube, it has to be added to the hard resin material. Therefore, in the case of the known example, since the hard resin layer is an inner tube, the entire tube cannot be imaged because the hard resin layer is an inner tube, whereas in the embodiment of FIGS. Therefore, the entire shape of the main tube 2 can be imaged.

Next, a catheter 1 according to another embodiment of the third invention will be described with reference to FIG. That is, the catheter 1 of the embodiment of FIG. 4 has a two-layer tube wall configuration of an outer tube 6 made of a soft resin layer whose hardness is opposite to that of FIG. 1 and an inner tube 5 made of a hard resin layer. The outer tube 6 has a thickness from the maximum thickness T1 of the front end portion 7 to the minimum thickness T2 of the rear end portion 8 and is provided with the flexible small tube leading portion 3 composed of only the soft resin layer. At least, at least the outer peripheral portion of the flexible leading portion 3 is a fine foamed resin layer 10.

In FIG. 4A, the entire flexible leading portion 3 is a fine foamed resin layer 10, and in FIG. 4B, "the outer peripheral portion is a fine foamed resin layer 10 and the inner peripheral portion is non-fine. Hybrid layer form made of foamed soft resin ". In the flexible leading portion 3 of the embodiment shown in FIG. 4, since a group of fine depressions due to fine foaming is present on the surface, a lubricant (hydrophilic polymer) and an antithrombotic agent (heparin) to facilitate insertion into a blood vessel are used. The adhesion and holding power is good, the insertability of the flexible leading portion 3 into the blood vessel and the pull-out property from the blood vessel are extremely improved, and the effect of preventing blood coagulation is improved. The adhesive strength between the main tube 2 and the flexible leading portion 3 is improved by the anchoring effect in which the adhesive or the molten resin of the main tube 2 when heated and fused to the fine recessed group enters and solidifies. Has a unique effect of improving safety by preventing intravascular separation and further reducing the weight of the flexible leading portion 3 to facilitate the operation of insertion into the blood vessel.

The finely foamed resin layer 10 is preferably made of a foaming agent having a high foaming temperature. In this embodiment, polystyrene EE-105 (manufactured by Eiwa Kasei Kogyo Co., Ltd.) of carbon dioxide foam having a decomposition temperature of 220 ° C. is used. The expansion ratio was 1.3 to 1.5.

In the catheter 1 of the present invention, the flexible leading portion 3 with the fine foam layer 10 of the embodiment of FIG. 4 may be connected to the main tube 2 of the embodiment of FIGS. In order to improve the connection strength of the tube 2, as shown in FIG. 4 (C), the two may be bonded and bonded at the tapered surface 9 or may be tapered as shown by the dotted line in the drawing. In addition, a three-layer structure in which a braided body (a tubular mesh body or the like) instead of the lining tube 4 is lined on the inner periphery of the inner tube 5 may be used.

1A shows a catheter of one embodiment of the first invention, (A) is a front sectional view thereof, (B) is an EE sectional view of (A), (C) is an FF sectional view of (A), and (D) is (A). ) GG sectional view The catheter of 2nd invention one Example is shown, (A) is the front sectional drawing, (B) is EE sectional drawing of (A), (C) is FF sectional drawing of (A). The catheter of another Example of 2nd invention is shown, (A) (B) is the front sectional drawing. The catheter of one Example of 3rd invention is shown, (A) is the front sectional drawing, (B) (C) is the partial front view. Explanatory drawing of bending characteristics of the catheter of the present invention

Explanation of reference numerals

Reference Signs List 1 catheter 2 main tube 3 flexible leading portion 4 lining tube 5 inner layer tube 6 outer layer tube 7 front end portion 8 rear end portion 10 fine foam layer

Claims (3)

A three-layered main tube provided with a lining tube inscribed in an inner tube of a gradually-varying laminated tube of a hard resin and a soft resin, wherein the stretched lining tube has a different soft hardness in a longitudinal direction by heat treatment. A catheter characterized by the following structure. It is composed of a main pipe in the form of a three-layer pipe provided with a lining pipe inscribed in the inner pipe of the gradually changing laminated pipe of hard resin and soft resin, and the lining pipe has a soft hardness in the longitudinal direction due to a gradually increasing taper shape. A catheter characterized by a differently configured structure. The catheter according to claim 1 or 2, wherein a flexible leading portion of a short small tube is integrally connected to an end of the main tube in the form of a three-layer tube .

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