JP3751866B2 - Balloon catheter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a balloon catheter used for dilating a vascular occlusion and placing a stent in a blood vessel.
[0002]
[Prior art]
As shown in FIG. 7, the conventional balloon catheter (11) is attached to the outer tube (12), the inner tube (13) inserted into the outer tube (12), and the tip of the outer tube (12). The guide wire (16) is inserted into the inner tube (13). The inner diameter of the inner tube (13) is, for example, 0.40 mm, the diameter of the guide wire (16) is, for example, 0.355 mm, and the difference is 0.045 mm.
[0003]
[Problems to be solved by the invention]
As described above, in the balloon catheter, the balloon catheter is introduced to a desired position in the blood vessel by guiding the guide wire inserted into the inner tube. When the vascular occlusion is expanded, an expansion solution such as physiological saline is fed into the gap between the balloon catheter and the inner tube.
When the guide wire is inserted into the inner tube of the balloon catheter, if the difference between the inner tube diameter and the guide wire diameter is small and the clearance is small, the wire operating force increases due to the wire sliding resistance, and the fingertip of the operator There is a risk that information sensitivity of the tip of the wire to be sensed is lowered, and the blood vessel is broken through the guide wire in the blood vessel occlusion portion.
[0004]
Furthermore, if the dilating fluid sent into the gap for dilating the balloon catheter does not flow out of the gap as soon as possible after the operation, the ischemic state will be prolonged, causing pain to the patient and increasing the risk of necrosis. There is.
[0005]
[Means for Solving the Problems]
The present invention comprises an outer tube (2) and an inner tube (3) as means for solving the above-mentioned conventional problems, and a balloon (4) is attached to the tip, and the balloon of the inner tube (3) (4) the inner part is enlarged (5), the inner tube (3) a balloon catheter (1) which guide wire (6) is inserted, the inner tube (3) is the main body portion (3A) and a tip portion (3B), the main portion (3A) is made of high-density polyethylene, and the tip portion (3B) is a modified polyethylene inner layer (31B) and a polyamide elastomer is an outer layer (32B). It consists of a two-layer pipe (3B), and the main body portion (3A) and the tip portion (3B) are formed by fusing the high-density polyethylene of the main body portion (3A) and the modified polyethylene of the tip portion inner layer (31B). The outer tube (2) and the balloon (4) are made of polyamide elastomer, and the outer tube (2) and the balloon (4) root end are made of a polyamide elastomer. Are connected by mutual fusion, the balloon (4) tip and the inner pipe (3) leading end portion outer layer (32B) is to provide a balloon catheter (1) which is connected by a polyamide elastomer mutual fusion .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with reference to an embodiment shown in FIGS. 1 to 6. A balloon catheter (1) shown in the drawings is provided at an outer tube (2), an inner tube (3), and a distal end portion of the outer tube (2). The balloon (4) is attached, and the tip of the balloon (4) is fixed to the outside of the tip of the inner tube (3). The inner tube (3) is expanded in diameter at the inner portion of the balloon (4) to form an expanded diameter portion (5).
[0007]
More specifically, the outer tube (2) and the balloon (4) are made of the same type of polyamide elastomer, and the main portion (3A) of the inner tube (3) is made of high-density polyethylene, and the inner surface of the balloon (4) The tip part (3B) including the expanded diameter part (5) of the inner tube (31B) is made of modified polyethylene, and the outer layer (32B) is made of the same type of polyamide elastomer as the balloon (4). (4) Root end and inner tube (3) Tip and balloon (4) The tip and inner tube main body (3A) and tip (3B) are fused together.
[0008]
The polyamide elastomer is, for example, an elastomer such as nylon 6, nylon 11, nylon 12, or nylon 66. From the viewpoint of low melting point and flexibility, nylon 12 elastomer is a desirable material.
[0009]
As the modified polyethylene, an α-β unsaturated fatty acid such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride or the like is graft-polymerized on polyethylene so that polar groups exist on the surface. Other than the above α-β unsaturated fatty acid or anhydride thereof, vinyl having other polar groups such as acrylamide, methacrylamide, glycidyl methacrylate, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, allyl alcohol, etc. The monomer may be graft polymerized.
[0010]
Further, in the present embodiment, the outer diameter (φ ₁ = 0.81 mm) of the outer pipe (2), the inner diameter φ ₂ = 0.70 mm, the outer diameter of the inner pipe main body (3A) φ ₃ = 0.50 mm, the inner diameter φ ₄ = 0.40 mm, outer diameter (5) of outer diameter φ ₅ = 0.52 mm, inner diameter φ ₆ = 0.42 mm, balloon (4) outer diameter φ ₇ = 3.50 mm, inner diameter φ ₈ = 3. 45 mm (8 atm expanded state), balloon (4) length l = 20 mm, catheter tip outer diameter φ ₉ = 0.50 mm, inner diameter φ ₁₀ = 0.39 mm.
[0011]
A guide wire (6) is inserted into the inner tube (3) of the catheter (1). The diameter of the guide wire (6) is φ ₁₁ = 0.355 mm.
[0012]
In order to mutually weld the inner pipe main part (3A) and the tip part (3B), first, as shown in FIG. 2, the inner layer (31B) is a modified polyethylene and the outer layer (32B) is a polyamide elastomer. The tube (3B) is manufactured by extrusion molding or the like. The inner diameter of the double-layer tube (3B) is 0.44 mm and the outer diameter is 0.66 mm. Next, as shown in FIG. 3, the polyamide elastomer of the outer layer (32B) is mechanically polished and peeled at the connection end of the two-layer pipe (3B) or partially dissolved and peeled with a solvent such as acid or alcohol.
[0013]
Next, as shown in FIG. 4, the inner tube main body portion (3A) is fitted inside the connection end of the two-layer tube (3B), and after inserting the metal core, the heat-shrinkable tube (7) is placed outside the connection portion. The inner tube main body portion (3A) and the two-layer tube (3B) are fused together by heating, and the heat-shrinkable tube (7) is heat-shrinked as shown in FIG. Fix the part. The heating temperature at this time is usually set to about 200 ° C.
[0014]
After fusing, the heat-shrinkable tube (7) is peeled off, and the inner pipe (3A) and the two-layer pipe (tip part (3B)) are fused to the inner pipe (3) connecting part. Die drawing is performed using a core metal and a die having dimensions, and the outer diameter and inner diameter are regulated as shown in FIG. The distal end portion of the catheter, that is, the fused portion between the distal end portion of the inner tube (3) and the distal end portion of the balloon (4) is similarly die-drawn and regulated to the aforementioned outer diameter inner diameter size and then cut to a predetermined size. The proximal side of the inner tube (3) also has a two-layer structure comprising an inner layer (31A) made of modified polyethylene and an outer layer (32A) made of polyamide elastomer.
[0015]
In the structure of the connecting portion, the connection between the inner tube main body portion (3A) and the tip portion (3B) is fusion of the high density polyethylene and the modified polyethylene of the inner layer (31B) of the tip portion (3B), and therefore High adhesive strength can be obtained. Further, since the modified polyethylene has polar groups on the surface, high adhesive strength can be obtained with the polyamide elastomer of the outer layer (32B). Further, since the outer layer (32B) of the tip portion (3B) is made of polyamide elastomer, high adhesive strength can be obtained with the balloon (4) made of polyamide elastomer. In this example, when the tensile strength at the bonded portion between the inner tube main body portion (3A) and the tip portion (3B) was measured, the material was broken and it was confirmed that the strength was 600 g or more.
[0016]
According to the above-described die drawing process, the accuracy of the outer diameter can be increased by the effect of reducing the diameter of the stretch, and high rigidity can be obtained by densifying the outer surface. As described above, since the inner tube (3) is provided with high rigidity, the inner tube (3) is hardly buckled, and the push-in characteristic is improved, so that the inner tube (3) can be inserted into the deep part of the body. Further, according to the die drawing process, if the strength of the bonded portion is low, the fracture occurs, so that the strength of the bonded portion can be confirmed and a highly safe catheter can be provided.
[0017]
A guide wire (6) is inserted into the inner tube (3) of the catheter (1) and introduced into, for example, a blood vessel occlusion. At this time, the surgeon tries to pass the guide wire (6) carefully while sensing information such as a sense of resistance obtained from the tip of the guide wire (6) with the fingertip. In this case, if the guide wire (6) can be operated lightly, the sensitivity to detect the above information with the fingertip is improved. If the sensitivity is improved, for example, the risk that the blood vessel is broken by the guide wire (6) in the blood vessel occlusion portion is eliminated.
[0018]
The guide wire (6) has a diameter φ ₁₁ = 0.355 mm, the inner pipe main body (3A) has an inner diameter φ ₄ = 0.40 mm, and the difference (clearance) is 0.045 mm. The inner diameter φ ₆ of (5) is 0.42 mm and the difference (clearance) is expanded to 0.065 mm. The operating force of the guide wire (6) is a function of the clearance, and the operating force decreases as the clearance increases. For example, when the clearance is 0.045 mm, the wire operating force is about 2.5 g, but when the clearance is 0.065 mm, the wire operating force is about 1.5 g, and the about 1 g operating force is small.
[0019]
The effect of expanding the diameter is not only reducing the wire operating force but also shortening the contraction time after the balloon (4) is expanded. That is, the balloon (4) is expanded by sending an expansion solution such as physiological saline into the gap between the inner tube (3) and the outer tube (2). In the balloon (4), the volume of the gap between the inner tube (3) and outer tube (2) is reduced by the diameter of the inner tube (3). Therefore, when the balloon (4) is deflated by allowing the expansion liquid to flow out of the gap, the amount of the expansion liquid flowing out decreases, and the contraction time of the balloon (4) can be shortened accordingly.
[0020]
If the balloon (4) expands in the blood vessel, it will become ischemic after this, and if this state continues, it will be painful for the patient, and as a result, necrosis of the part beyond this will be caused. In the present invention, as described above, due to the diameter expansion effect of the inner tube (3), the outflow amount of the expansion liquid from the inner side of the balloon (4) can be reduced, and the deflation time of the balloon (4) can be shortened (this implementation). In the case of the example, it is 5.2 seconds when there is no enlarged portion, and 4.5 seconds when there is an enlarged portion). The pain of the practitioner can be reduced and necrosis can be prevented.
[0021]
【The invention's effect】
In the present invention, since the inner tube is expanded in diameter at the inner portion of the balloon, the operation force of the guide wire inserted into the inner tube is reduced, and the information sensitivity sensed by the operator's fingertip is improved. The risk of breaking the blood vessel with the guide wire in the obstruction is eliminated, and the volume of the gap between the balloon and the inner tube is further reduced by the diameter of the inner tube, so that the expansion liquid flows out from the gap. When the balloon is deflated, the outflow amount of the expansion fluid is reduced, and the deflation time of the balloon is shortened accordingly, the ischemic state time is shortened, the pain of the patient can be reduced, and necrosis can be prevented.
[Brief description of the drawings]
1 to 6 show an embodiment of the present invention.
FIG. 1 is a partial sectional view of a catheter balloon. FIG. 2 is a sectional side view of a two-layer tube (inner tube). FIG. 3 is a sectional side view of a two-layer tube connection portion. Explanatory drawing of connection process with (tip) (before heat fusion)
FIG. 5 is an explanatory diagram of the connection process between the inner tube main body and the two-layer tube (tip portion) (after heat fusion)
FIG. 6 is a cross-sectional side view of an inner tube portion after die drawing processing. FIG. 7 is a cross-sectional side view of a catheter balloon portion of a conventional example.
1 Balloon catheter
2 Outer tube
3 Inner tube
3A inner pipe main part
3B Inner tube tip (double-layer tube)
31B inner layer
32B outer layer
4 balloon
5 Expanded part
6 Guide wire

Claims (1)

A balloon catheter comprising an outer tube and an inner tube, a balloon is attached to the distal end, the inner diameter portion of the inner tube is enlarged, and a guide wire is inserted into the inner tube , The inner tube is composed of a main portion and a tip portion, the main portion is made of high-density polyethylene, and the tip portion is a two-layer tube having a modified polyethylene as an inner layer and a polyamide elastomer as an outer layer. And the outer tube and the balloon are made of polyamide elastomer, and the outer tube and the balloon root end are made of polyamide. The balloon tip and the inner tube tip part outer layer are connected by polyamide elastomer mutual fusion. The balloon catheter according to claim Rukoto

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