JPH0530469B2 - - Google Patents

Description

[Detailed description of the invention]

[0001]

TECHNICAL FIELD The present invention relates to a catheter, and more particularly to a catheter that can be smoothly inserted into a blood vessel or the like.

【0002】

[Prior Art] A catheter 1 as shown in FIG.
is guided by a guide wire or the like and inserted into a body cavity such as a blood vessel, and the direction of its tip is controlled so that it can reach a target site, making it possible to perform treatment or examination.

[0003] Therefore, in the case of this catheter 1, the main body portion 2 is required to have a certain degree of hardness, that is, relatively small flexibility, and the distal end portion 3 is required to have a certain degree of flexibility, that is, relatively small flexibility. It is required to have great flexibility. In particular, in the catheter 1 for the vascular system, the main body 2
In order to transmit the pushing force to the tip 3, a certain degree of hardness, ie, relatively small flexibility, is required up to the vicinity of the tip 3. On the other hand, the distal end portion 3 is pre-formed with various curved shapes depending on the type of catheter 1, and has flexibility so that the curved shape follows the guide wire when inserted.
It is necessary to have a straight shape along the guide wire to facilitate insertion, and also to have flexibility, that is, a relatively large amount of flexibility, so as not to damage the inner wall of the heart or blood vessel when it is placed in the heart or blood vessel.

[0004] Therefore, in the catheter 1, the main body part 2 and the distal end part 3 each have substantially constant hardness, that is, relatively small flexibility, over substantially the entire area thereof, and
It is desirable to have softness or relatively great flexibility.

[0005]

[Problems to be Solved by the Invention] Conventionally, a catheter 1 is made up of a main body portion 2 having relatively low flexibility as described above and a distal end portion 3 having relatively high flexibility.
A catheter 1 has been proposed in which a main body part 2 and a distal end part 3 are connected by adhesive, fusion, or the like. However, in the case of the conventionally proposed catheter 1, the manufacturing process is complicated, and there is a step at the connection between the main body part 2 and the distal end part 3, making it difficult to smoothly insert it into a blood vessel, etc. It is difficult and may cause blood clots. In addition, due to a poor connection between the main body portion 2 and the tip portion 3, there is a risk of disconnection or the like due to separation between the two.

[0006] The present invention provides a catheter in which the main body portion and the distal end portion each have substantially constant hardness and flexibility over substantially the entire area thereof, and are integrally molded without forming a step between the two. The purpose is to provide

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a structure in which a tubular main body portion having relatively low flexibility and a tubular tip portion having relatively high flexibility are arranged in the axial direction. In a catheter formed integrally, the catheter has at least an inner tube portion and an outer tube portion continuous with the main body portion and the distal end portion, and the inner tube has a wall thickness different between the main body portion and the distal end portion. The outer tube part is coated and molded on the outer surface of the part, and of the two tube parts, the inner tube part and the outer tube part, the wall thickness at the tip part is thicker than the other tube part, and the main body is thicker than the other tube part. The flexibility of the tube section whose wall thickness is thinner than that of the other tube section is made greater than the flexibility of the other tube section, and the inner tube section and the outer tube section of the main body section are The wall thickness of each tube part is constant, and the wall thickness of the inner tube part and the outer tube part at the tip part are also constant, so that the main body part and the tip part are integrally formed without forming a step between them. It is made to look like it is molded.

[0008] Further, in the present invention, the bending elastic modulus of the main body portion is 2800 to 3200 Kg/cm ² and the bending elastic modulus of the tip portion is 1000 to 1400 Kg/cm ² .

[0009] Furthermore, in the present invention, the outer diameter and inner diameter of the catheter are uniform over both the main body portion and the distal end portion.

[0010] Furthermore, the present invention is such that the main body portion and the distal end portion are smoothly continuous without creating a step on the inner and outer surfaces thereof.

[0011] Furthermore, the present invention is such that the wall thickness at the boundary portion between the main body portion and the tip portion changes smoothly.

【0012】

Embodiment FIG. 2 is a sectional view showing a catheter 10 according to a first embodiment of the present invention.

[0013] As shown in FIG. 2, the catheter 10 includes a main body part 11 with a length _L1 and a distal end part ₁₂ with a length L2.
are integrally molded in the axial direction, and an outer tube portion 14 is coated and molded on the upper surface of an inner tube portion 13 whose wall thicknesses differ between the main body portion 11 and the tip portion 12. Here, the inner tube part 13 has a substantially constant inner diameter, and is set so that the wall thickness at the main body part 11 is thick and the wall thickness at the distal end part 12 is thin. Further, the outer tube portion 14 has a substantially constant outer diameter, a thinner wall thickness in the main body portion 11, and a tip portion 12.
The wall thickness is set thick. In addition, the main body part 11 and the tip part 1 of each inner tube part 13 and outer tube part 14
The wall thickness change at the boundary with 2 is not a step-like change as shown in FIG. 2, but a smooth taper-like change.

[0014] Here, since the wall thickness of the inner tube portion 13 is thicker than that of the main body portion 11, its flexibility is smaller than that of the outer tube portion 14. For example, the flexural modulus is 2800 to 3200Kg/
cm ² , preferably 3000 Kg/cm ² of polyamide elastomer. On the other hand, the outer tube part 1
No. 4 has relatively high flexibility, for example, a bending modulus of elasticity of 1000 to 1400 Kg/cm ² , preferably 1200 Kg/cm ²
It is made of polyamide elastomer.
That is, the main body portion 11 of the catheter 10 has a thick walled component portion formed into a relatively flexible inner tube portion 13.
The overall flexibility is relatively low. Further, the distal end portion 12 of the catheter 10 has a thick walled component formed by a relatively flexible outer tube portion 14, and has relatively high flexibility as a whole.

[0015] Then, the inner tube part 1 in the main body part 11
The wall thickness of the outer tube 14 of the main body portion 11 is constant and thick as described above. Further, the wall thickness of the inner tube section 13 at the tip end 12 is thin and constant as described above, and the wall thickness of the outer tube section 14 at the tip end 12 is constant and thick as described above. . That is, for the catheter 10,
The inner tube portion 13 and the outer tube portion 14 in the main body portion 11 have a constant wall thickness, and as a result, the inner tube portion 13 and the outer tube portion 14 have a constant wall thickness.
1 has substantially constant hardness, that is, relatively small flexibility over substantially the entire area. Furthermore, the wall thicknesses of the inner tube section 13 and the outer tube section 14 in the distal end section 12 are each made constant, and as a result, the distal end section 12 has substantially constant flexibility, that is, relatively large flexibility, over substantially the entire area.

[0016] In the catheter 10, the wall thickness changes in the boundary region between the main body part 11 and the distal end part 12 of each of the inner tube part 13 and the outer tube part 14 are shown in FIG.
As shown in FIG.
The change in flexibility between the
It can be smoothly inserted into a blood vessel or the like.

[0017] The catheter 10 is put into use after the catheter hub is connected to the end of the main body 11 and the distal end 12 is given a necessary bent shape.

[0018] That is, according to the first embodiment,
It is possible to obtain a catheter 10 in which the main body portion 11 and the distal end portion 12 are integrally molded with substantially constant hardness and flexibility over substantially the entire area thereof. Here, the inner diameters of the main body part 11 and the distal end part 12 of the catheter 10 are formed by the inner tube part 13, and the outer diameters thereof are formed by the outer tube part 14. There is no difference in level between the inner and outer surfaces of the boundary area with the main body part 11 and the distal end part 12, which allows smooth insertion into a blood vessel, etc., and prevents the formation of blood clots. There is no risk of separation between the parties.

[0019] Next, a method for manufacturing the catheter 10 will be described. First, the inner tube part 13, in which the main body part 11 is thicker than the tip part 12 and has relatively little flexibility, is manufactured by extrusion molding or the like.
For example, the inner tube part 13 is made of polyamide elastomer with a bending modulus of elasticity of 3000 Kg/cm ² , and the main body part 11 has an inner diameter of 1.4 mm and an outer diameter of 2.1 mm, and the tip part 12 has an inner diameter of 1.4 mm and an outer diameter of 1.6 mm. Next, the upper surface of the inner tube section 13 is covered with an outer tube section 14 whose flexibility is relatively greater than that of the inner tube section 13 . For example, using polyamide elastomer with a bending modulus of 1200 kg/cm ² ,
The outer tube portion 14 of 2.3 mm is covered. Next, the inner tube portion 13 and outer tube portion 14 integrally molded as described above are cut to a required length to obtain the catheter 10.

[0020] FIG. 3 is a sectional view showing a catheter 20 according to a second embodiment of the present invention.

[0021] This catheter 20 is different from the catheter 10 described above in that a wire layer 21 made of stainless steel wire with a wire diameter of 0.08 mm is woven with a pitch of 1 mm, for example, between the inner tube part 13 and the outer tube part 14. It is only in the dots. More specifically, the wire layer 21 is provided between the inner tube section 13 and the outer tube section 14 having a constant wall thickness of the main body section 11 . Main body part 11 and tip part 1
Since the wire layer 21 is not present at the boundary between the wire layer 2 and the wire layer 2, there is no sudden change in flexibility and kinks are less likely to occur.

[0022] Therefore, according to the second embodiment, the main body part 11 and the distal end part 12, which are similar to the catheter 10 described above, can be integrally molded reliably and without forming a step between the two, and Main body part 1
It is possible to obtain a catheter 20 in which the torsional rigidity of the catheter 1 is increased, and the distal end portion 12 can be directed more accurately by a twisting operation applied to the main body portion 11.

[0023] In each of the above embodiments, the wall thickness of the inner tube part 13 is made thicker than that of the main body part 11, and the flexibility of the inner tube part 13 is made smaller than the flexibility of the outer tube part 14. The case where it is made smaller has been explained. However, in the catheter according to the present invention, as in the catheter 30 shown in FIG.
2A may be made thicker, and the flexibility of the inner tube portion 13A may be greater than that of the outer tube portion 14A. This makes it easier for the torque at hand to be transmitted to the tip.

[0024] In the case of this catheter 30, the wall thickness of the inner tube part 13A in the main body part 11A is kept constant and thin as described above, and the main body part 1
By making the wall thickness of the outer tube part 14A in 1A constant and thick as described above, as a result, almost the entire area of the main body part 11A has approximately constant hardness, that is, relatively small flexibility. . In addition, the tip portion 12A
By making the wall thickness of the inner tube portion 13A constant in the thick shape as described above and the thickness of the outer tube portion 14A in the distal end portion 12A being constant in the thin shape as described above, as a result. The tip portion 12A has substantially constant flexibility, that is, relatively large flexibility, over substantially the entire area.

[0025] Next, the operation of the present invention will be explained. Catheters 10, 20 according to each of the above embodiments,
The device 30 is guided by, for example, a guide wire and inserted into a body cavity such as a blood vessel, and the direction of its tip is controlled so that it can reach a target site, thereby making it possible to perform treatment or examination.

[0026] Here, each of the above catheters 10, 2
0,30, as mentioned above, the main body part 1
The tips 12, 11A have a certain degree of hardness, that is, relatively small flexibility, over almost the entire area of the tips 12, 11A.
12A has a certain degree of flexibility that is substantially constant, that is, a relatively large flexibility. Therefore, when each of the catheters 10, 20, 30 is inserted into, for example, a blood vessel and pushed forward, substantially the entire area of the distal end portions 12, 12A can easily be inserted along the guide wire, and the blood vessel wall can be easily inserted. Without causing any damage, the body portions 11, 11A ensure that the pushing force is properly transmitted to the tip portions 12, 12A.

[0027] Furthermore, each of the above catheters 10, 2
0,30, as mentioned above, the main body part 1
There is no difference in level between the inner and outer surfaces of the boundary area between the tip portions 1 and 11A and the tip portions 12 and 12A. Therefore, it is possible to smoothly insert it into a blood vessel, etc., and no thrombus is generated. Further, separation does not occur between the main body portions 11, 11A and the tip portions 12, 12A.

【0028】

Effects of the Invention As described above, the present invention provides a catheter in which a tubular body portion having relatively low flexibility and a tubular tip portion having relatively high flexibility are integrally molded in the axial direction. The catheter has at least an inner tube section and an outer tube section that are continuous with the main body section and the distal end section, and the outer tube is attached to the outer surface of the inner tube section with different wall thicknesses between the main body section and the distal end section. The part is covered and molded,
Of the two pipe parts, the inner pipe part and the outer pipe part, the wall thickness at the tip part is thicker than the other pipe part, and the wall thickness at the main body part is thinner than the other pipe part. The flexibility of one tube section is greater than the flexibility of the other tube section, the thickness of the inner tube section and the outer tube section of the main body section are each constant, and the thickness of the inner tube section and the outer tube section of the main body section are made constant, and the The wall thicknesses of the inner tube portion and the outer tube portion are also constant, and the main body portion and the distal end portion are integrally molded without forming a step between them.

[0029] Further, in the present invention, the bending elastic modulus of the main body is 2800 to 3200 Kg/ ^cm2 , and the bending elastic modulus of the tip is 1000 to 1400 Kg/ ^cm2 .

[0030] Furthermore, in the present invention, the outer diameter and inner diameter of the catheter are uniform over both the main body portion and the distal end portion.

[0031] Further, in the present invention, the main body portion and the distal end portion are smoothly continuous without forming a step on the inner and outer surfaces thereof.

[0032] Furthermore, in the present invention, the wall thickness at the boundary portion between the main body portion and the tip portion changes smoothly.

[0033] Therefore, according to the present invention, the main body portion and the tip portion each have substantially constant hardness and flexibility over substantially the entire area thereof, and are integrally formed without forming a step between the two. It is now possible to obtain a catheter that is shaped like this, which allows for smooth insertion into blood vessels, etc., and eliminates the possibility of thrombus formation and the risk of dislodgement between the main body and the distal end. Nor. Further, by setting the bending elastic modulus of the main body to 2,800 to 3,200 Kg/cm ² , preferably 3,000 Kg/cm ² , the pushing force when inserting the catheter into a blood vessel can be accurately transmitted to the distal end. In addition, the bending elastic modulus of the tip should be set to 1000~
By setting it to 1400 Kg/cm ² , preferably 1200 Kg/cm ² , it is possible to provide flexibility that allows the catheter to be inserted into a blood vessel without damaging the blood vessel wall. If desired, a catheter with even better biocompatibility can be obtained by providing a layer of a biocompatible material such as silicone resin, silicone-urethane copolymer, segmented polyurethane, etc. on the outer surface of the catheter. Furthermore, since the wall thickness changes smoothly at the boundary between the main body and the distal end, the flexibility changes smoothly, making it easier to insert the catheter into a blood vessel or the like.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a general catheter.

FIG. 2 is a sectional view showing a catheter according to a first embodiment of the present invention.

FIG. 3 is a sectional view showing a catheter according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a catheter according to still another embodiment of the present invention.

[Explanation of symbols]

10, 20, 30 catheter 11,11A Main body 12,12A tip 13,13A Inner pipe part 14,14A Outer tube part

Claims (5)

[Claims] 1. A catheter comprising a tubular main body with relatively low flexibility and a tubular distal end with relatively high flexibility, which are integrally formed in the axial direction. It has at least an inner tube part and an outer tube part continuous with the tip part, and the outer tube part is coated and molded on the outer surface of the inner tube part whose wall thickness is different between the main body part and the tip part. Of the two pipe parts, the pipe part and the outer pipe part, the wall thickness at the tip part is thicker than the other pipe part, and the wall thickness at the main body part is thinner than the other pipe part. The flexibility of one tube portion is greater than the flexibility of the other tube portion, and the wall thicknesses of the inner tube portion and the outer tube portion of the main body portion are each constant,
A catheter characterized in that the wall thicknesses of the inner tube portion and the outer tube portion at the distal end portion are also constant, and the main body portion and the distal end portion are integrally molded without forming a step between the two. . [Claim 2] The bending elastic modulus of the main body is 2800 to 3200.
Kg/cm ² , and the bending modulus of the tip is 1000 to 1400.
The catheter according to claim 1, which has a weight of Kg/cm ² . 3. The catheter according to claim 1, wherein both the outer diameter and the inner diameter of the catheter are uniform over the main body portion and the distal end portion. 4. The catheter according to claim 1, wherein the main body portion and the distal end portion are smoothly continuous with each other without forming a step on the inner and outer surfaces thereof. 5. The catheter according to claim 1, wherein the wall thickness at the boundary between the main body portion and the distal end portion changes smoothly.