catheter

Abstract

It suppresses the peeling of the outer layer of the catheter. [Solution] The catheter comprises a tubular inner layer, a tubular intermediate layer, and a tubular outer layer. The inner layer is made of a material containing fluororesin. The intermediate layer covers the outer surface of the inner layer and is made of resin. The outer layer covers the outer surface of the intermediate layer. The thickness of the intermediate layer is 0.6 μm or more.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a catheter.

Background Art

[0002] A catheter is used, for example, when treating a lesion in a biological lumen such as a blood vessel. The catheter has, for example, a tubular inner layer formed of polytetrafluoroethylene (PTFE) and a tubular outer layer covering the outer periphery of the inner layer (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Fluororesins such as PTFE are materials with poor adhesiveness and tackiness. Therefore, in known catheters, the outer layer may peel off.

[0005] This specification discloses a technology capable of solving the above-described problems.

Means for Solving the Problems

[0006] The technology disclosed in this specification can be realized, for example, in the following forms.

[0007] The catheter disclosed in this specification includes a tubular inner layer, a tubular intermediate layer, and a tubular outer layer. The inner layer is formed of a material containing a fluororesin. The intermediate layer covers the outer peripheral surface of the inner layer and is formed of a resin. The outer layer covers the outer peripheral surface of the intermediate layer. The film thickness of the intermediate layer is 0.6 μm or more. In this catheter, peeling of the outer layer is suppressed.

Brief Description of the Drawings

[0008] [Figure 1] Explanatory diagram showing a longitudinal section of the catheter in the embodiment. [Figure 2] Diagram illustrating the cross-section of the catheter at position II-II in Figure 1. [Figure 3] Diagram illustrating the performance evaluation results regarding adhesion strength. [Figure 4] Diagram illustrating the performance evaluation results regarding adhesion strength. [Modes for carrying out the invention]

[0009] (Embodiment) (Components of Catheter 100) Figure 1 is an explanatory diagram showing a longitudinal section (YZ section) of the catheter 100 in an embodiment. Figure 1 shows a portion of the longitudinal section of the catheter 100 along the long axis. Figure 2 is an explanatory diagram showing a cross section (XY section) of the catheter 100 at position II-II in Figure 1.

[0010] The positive Z-axis side of catheter 100 is the distal end (tip) that is inserted into the body. The negative Z-axis side of catheter 100 is the proximal end (proximal) that is manipulated by the operator. In catheter 100 and its components, tip means the tip end, tip portion means the tip and its vicinity, proximal end means the proximal end, and proximal end portion means the proximal end and its vicinity. In catheter 100 and its components, longitudinal section means a section parallel to the central axis Ax of catheter 100, and transverse section means a section perpendicular to the central axis Ax.

[0011] Catheter 100 is a tubular medical device with an open tip and a proximal end. Catheter 100 is used, for example, to treat a lesion. The cross-sectional shape of catheter 100 can be, for example, circular, partially circular, elliptical, rectangular, parallelogram, trapezoidal, or rhombic. The cross-sectional shape may differ depending on the part of catheter 100.

[0012] The catheter 100 includes an inner layer 40, an outer layer 50, an intermediate layer 60, and a reinforcing body 30.

[0013] The inner layer 40 is a tubular member with an open tip and base. The hollow portion of the inner layer 40 functions, for example, as a lumen S into which another medical device is inserted. The film thickness of the inner layer 40 is, for example, 8 μm or more and 25 μm or less. In this specification, the film thickness of each layer refers to the average film thickness. The average film thickness is the average of the measured film thickness at five measurement points set approximately uniformly in the circumferential direction.

[0014] The inner layer 40 is formed from a material containing fluororesin. Examples of materials for forming the inner layer 40 include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-ethylene copolymer (ETFE). The entire inner layer 40 may be formed from the same material. The inner layer 40 may be formed from different materials in different parts.

[0015] The outer layer 50 is a tubular member with an open tip and base. The outer layer 50 is positioned on the outer circumference of the inner layer 40. The thickness of the outer layer 50 is, for example, 10 μm or more and 200 μm or less.

[0016] The outer layer 50 is formed of, for example, a resin material. Examples of materials for forming the outer layer 50 include polyamide resins, polyurethane resins, and polyolefin resins. In this embodiment, the outer layer 50 is formed of polyetheretherketone (PEEK). The entire outer layer 50 may be formed of the same material. The outer layer 50 may be formed of different materials in different parts.

[0017] The intermediate layer 60 is a tubular member with openings at its tip and base. The intermediate layer 60 is disposed between the inner layer 40 and the outer layer 50. The intermediate layer 60 covers the outer peripheral surface of the inner layer 40. The outer peripheral surface of the intermediate layer 60 is covered by the outer layer 50. The film thickness t1 of the intermediate layer 60 is, for example, 0.6 μm or more and 10.0 μm or less. The film thickness t1 of the intermediate layer 60 may be 1.0 μm or more and 7.0 μm or less, or may be 1.3 μm or more and 5.0 μm or less. In the present embodiment, the film thickness t1 of the intermediate layer 60 is thinner than the film thickness of the inner layer 40. The film thickness t1 of the intermediate layer 60 is thinner than the film thickness of the outer layer 50.

[0018] The intermediate layer 60 is formed of a resin material. The intermediate layer 60 is formed of, for example, a resin material with relatively high flexibility. Examples of such resin materials include elastomeric resins such as low-hardness polyamide elastomers and thermoplastic polyurethane elastomers. The entire intermediate layer 60 may be formed of the same material. The intermediate layer 60 may be formed of different materials for each part.

[0019] The intermediate layer 60 can be formed by known melt extrusion. As a method for forming the intermediate layer 60, a coating method using a solution in which a resin is dissolved in a solvent may be employed. Examples of the coating method include a method of applying the above solution to the outer peripheral surface of the inner layer 40 and a method of dipping the inner layer 40 into the above solution. By adopting the above coating method, for example, an intermediate layer 60 with a film thickness t1 of 10 μm or less can be formed.

[0020] The reinforcing member 30 is a tubular member with openings at its tip and base. In the present embodiment, the reinforcing member 30 is a braided body in which a plurality of strands 32 are braided so as to cross each other. The reinforcing member 30 is disposed between the intermediate layer 60 and the outer layer 50. More specifically, the reinforcing member 30 is disposed on the outer peripheral surface of the intermediate layer 60.

[0021] The reinforcing member 30 is formed of a metallic material. Examples of the material for forming the reinforcing member 30 include tungsten and stainless steels (SUS302, SUS304, SUS316, etc.). The reinforcing member 30 may be entirely formed of the same material. The reinforcing member 30 may be formed of different materials for each part.

[0022] (Performance Evaluation) Figures 3 and 4 are explanatory diagrams showing the performance evaluation results regarding the adhesive strength. The graph in Figure 4 shows an enlarged view of a partial area of the graph in Figure 3.

[0023] In this performance evaluation, a plurality of samples with different film thicknesses t1 of the intermediate layer 60 of the catheter 100 were produced, and the force required to peel off the outer layer 50 was measured as the adhesive strength. When the film thickness t1 of the intermediate layer 60 is large, the outer peripheral length of the intermediate layer 60 becomes long, and the contact area between the intermediate layer 60 and the outer layer 50 becomes large. Therefore, in this performance evaluation, the above adhesive strength was compared by the adhesive strength per unit area obtained by dividing the adhesive strength by the area calculated by the outer peripheral length of the intermediate layer 60 × unit length.

[0024] The method for producing the sample is as follows. First, an operator prepared an inner layer 40 formed of PTFE. Next, the operator formed an intermediate layer 60 on the outer peripheral surface of the inner layer 40 using Pebax 35 (Pebax is a registered trademark). More specifically, the operator formed the intermediate layer 60 by dipping the inner layer 40 into a solution in which Pebax 35 was dissolved in a solvent. Next, the operator formed an outer layer 50 by welding PEEK onto the outer peripheral surface of the intermediate layer 60. Next, the operator obtained a sample of the catheter composed of the inner layer 40, the intermediate layer 60, and the outer layer 50 by performing stretching and core removal.

[0025] Figures 3 and 4 show plots for each sample showing the measurement results of the film thickness t1 of the intermediate layer 60 and the adhesion force per unit area. Figures 3 and 4 also show the approximate curve C0 calculated from each plot, curves C1 and C2 that show the region considering the variation of plus or minus 3σ centered on the approximate curve C0, and a straight line SL1 that shows the value Th of the adhesion force per unit area in a comparative example in which the inner layer 40 and the outer layer 50 were joined without the intermediate layer 60.

[0026] As shown in Figures 3 and 4, the greater the film thickness t1 of the intermediate layer 60, the greater the adhesion force per unit area. If the film thickness t1 of the intermediate layer 60 is 0.6 μm or more, even considering variations, an adhesion force greater than that of the comparative example in which the inner layer 40 and outer layer 50 are joined without an intermediate layer 60 can be obtained.

[0027] A delamination test was performed using a catheter sample similar to the one described above. In the delamination test, the operator chucked both ends of the sample with a tensile testing machine (Shimadzu Autograph AGS-X) and applied a tensile load to the sample to cause it to break. More specifically, the operator prepared a catheter sample with a total length of 60 mm, and clamped the portion from the tip to 15 mm of the sample in the upper chuck of the tensile testing machine and fixed it with a chuck pressure of 0.6 MPa, and clamped the portion from the base to 15 mm of the sample in the lower chuck of the tensile testing machine and fixed it with a chuck pressure of 0.6 MPa. That is, the distance between the chucks was 30 mm. After this setting was completed, the operator operated the tensile testing machine and, with the position of the lower chuck fixed, moved the upper chuck upward at a speed of 100 mm / min to apply a tensile load to the sample and cause it to break. The operator observed the fracture surface to check for the presence or absence of delamination. The worker determined that there was "no delamination" if the inner layer 40, intermediate layer 60, and outer layer 50 all fractured simultaneously, and that there was "delamination" if the outer layer 50 fractured but the inner layer 40 did not. Table 1 shows the results of the delamination test.

[0028] [Table 1]

[0029] As shown in Table 1, delamination occurred in samples where the thickness t1 of the intermediate layer 60 was less than 0.6 μm. No delamination occurred in samples where the thickness t1 of the intermediate layer 60 was 0.6 μm or greater. From these results, it can be concluded that delamination can be suppressed if the thickness t1 of the intermediate layer 60 is 0.6 μm or greater.

[0030] (Effects of this embodiment) As described above, the catheter 100 of this embodiment has a tubular inner layer 40, a tubular intermediate layer 60, and a tubular outer layer 50. The inner layer 40 is made of a material containing fluororesin. The intermediate layer 60 is made of resin. The intermediate layer 60 covers the outer circumferential surface of the inner layer 40. The outer layer 50 covers the outer circumferential surface of the intermediate layer 60. The film thickness t1 of the intermediate layer 60 is 0.6 μm or more. The catheter 100 of this embodiment includes an intermediate layer 60 having a film thickness t1 of 0.6 μm or more between the inner layer 40 and the outer layer 50. Therefore, peeling of the outer layer 50 is suppressed.

[0031] In the catheter 100 of this embodiment, the intermediate layer 60 may be formed of an elastomer resin. This effectively suppresses the peeling of the outer layer 50.

[0032] In the catheter 100 of this embodiment, the film thickness t1 of the intermediate layer 60 may be 7.0 μm or less. This suppresses at least one of the following: an increase in the outer diameter of the catheter 100 or a decrease in the inner diameter of the catheter 100. The film thickness t1 of the intermediate layer 60 may be thinner than the film thickness of the inner layer 40. This effectively suppresses at least one of the following: an increase in the outer diameter of the catheter 100 or a decrease in the inner diameter of the catheter 100. The film thickness t1 of the intermediate layer 60 may be thinner than the film thickness of the outer layer 50. This effectively suppresses at least one of the following: an increase in the outer diameter of the catheter 100 or a decrease in the inner diameter of the catheter 100.

[0033] In the catheter 100 of this embodiment, the outer layer 50 may be formed of polyetheretherketone. Doing so improves the performance of the catheter 100, such as its stretch resistance.

[0034] The catheter 100 of this embodiment further includes a metal reinforcing body 30 positioned between the intermediate layer 60 and the outer layer 50. This ensures the necessary rigidity of the catheter 100.

[0035] (modified version) The technologies disclosed herein are not limited to the embodiments described above and can be modified in various forms without departing from their essence, for example, the following modifications are possible.

[0036] The configuration of the catheter 100 in the above embodiment is merely an example and can be modified in various ways. For example, the reinforcing body 30 may be a configuration other than a braided body (for example, a coil). The catheter 100 may not have a reinforcing body 30. The catheter 100 may have other layers arranged on the outer circumference of the outer layer 50.

[0037] The forming materials for each component constituting the catheter 100 in the above embodiment are merely examples and can be modified in various ways.

Claims

1. A catheter (100), A tubular inner layer (40) formed from a material containing fluororesin, A tubular intermediate layer (60) is formed of resin and covers the outer surface of the inner layer (40), with a film thickness of 0.6 μm or more. A tubular outer layer (50) covering the outer surface of the intermediate layer (60), A catheter (100) equipped with [a specific feature].

2. A catheter (100) according to claim 1, The intermediate layer (60) is formed of an elastomer resin, and the catheter (100) is a catheter.

3. A catheter (100) according to claim 1 or claim 2, A catheter (100) having a thickness of 7.0 μm or less of the intermediate layer (60).

4. A catheter (100) according to any one of claims 1 to 3, A catheter (100) in which the thickness of the intermediate layer (60) is thinner than the thickness of the inner layer (40).

5. A catheter (100) according to any one of claims 1 to 4, The outer layer (50) is formed of polyether ether ketone, and the catheter (100) is also provided.

6. A catheter (100) according to any one of claims 1 to 5, A catheter (100) further comprising a metal reinforcing body (30) disposed between the intermediate layer (60) and the outer layer (50).

Images