JP2024066603A - catheter - Google Patents

Abstract

[Problem] To provide a catheter with improved hub strength. [Solution] The catheter 1 is a catheter in which reinforcing wires 14, 15 are woven together, and when viewed in cross section in the longitudinal direction, the alignment angles of the reinforcing wires arranged on the inside and the reinforcing wires arranged on the outside are different when a virtual line L is drawn that intersects the reinforcing wires arranged on the inside and the outside. [Selected Figure] Figure 2

Description

The present invention relates to a catheter.

A guiding catheter is a type of catheter that is used to guide a PTCA catheter or other catheter used to treat the coronary arteries of the heart when it is inserted to the target site (see, for example, Patent Document 1 below).

JP 2006-288670 A

In general, if the strength of the joint between the hub and tube of a guiding catheter (hub strength) is low, the joint may break, for example, if the guiding catheter becomes stuck inside the body and is subjected to a tensile load.

The present invention has been made to solve the above-mentioned problems, and aims to provide a catheter with improved hub strength.

The above object of the present invention is achieved by the following means:

(1)
A catheter in which reinforcing wires are braided together,
In cross-sectional view along the long axis,
A catheter in which imaginary lines drawn intersecting an inner reinforcing wire and an outer reinforcing wire have different alignment angles.

(2)
The catheter according to (1), wherein the difference in the alignment angle between the inner reinforcing wire and the virtual wire, and the outer reinforcing wire and the virtual wire, is 2 to 8°.

(3) A catheter as described in (1) or (2), in which at least one of the reinforcing wires arranged on the inside and the reinforcing wires arranged on the outside is a flat plate.

With a catheter configured as described above, the alignment angles when a virtual line is drawn that intersects the reinforcing wire arranged on the inside and the reinforcing wire arranged on the outside are different, so compared to when the alignment angles are the same, the effect of the reinforcing wire as an anchor when the catheter is pulled is improved, and the hub strength can be improved. From the above, it is possible to provide a catheter with improved hub strength.

1 is an overall view showing a catheter according to an embodiment of the present invention. FIG. 2 is a front cross-sectional view showing a tube of the catheter according to the embodiment. FIG. 2 is a cross-sectional view perpendicular to the axis showing a tube of the catheter according to the embodiment. FIG. 1 is a front view showing a catheter according to an embodiment of the present invention.

A catheter 1 according to an embodiment of the present invention will now be described with reference to Figures 1 to 4. Figure 1 is an overall view of a catheter 1 according to an embodiment of the present invention. Figure 2 is a front cross-sectional view of a tube 10 of a catheter 1 according to this embodiment. Figure 3 is an orthogonal cross-sectional view of a tube 10 of a catheter 1 according to this embodiment. Figure 4 is a front view of a catheter 1 according to this embodiment.

The catheter 1 shown in Figure 1 is used as a guiding catheter to guide a treatment catheter (device), such as a PTCA dilatation catheter (balloon catheter) or a catheter (stent delivery catheter) for transporting a stent in a contracted state to a stenotic area, expanding it at the stenotic area, and retaining it there to keep it expanded, to a target area, such as a stenotic area in a coronary artery.

As shown in Figures 1 to 4, the catheter 1 has a tube 10, a flexible tip 20 provided at the distal end of the tube 10, and a hub (hub tube) 30 provided at the proximal end of the tube 10, and a kink-resistant protector 40 is provided at the distal end of the hub 30.

The tube 10 is made of a flexible tubular body. A lumen 10H is formed in the tube 10 over the entire length of the tube 10. The lumen 10H opens at the tip of the distal tip 20.

As shown in FIG. 2, the tube 10 has an inner layer 11 arranged on the inner surface side, an outer layer 12 arranged on the outer periphery of the inner layer 11, and a reinforcing material layer 13 arranged inside the outer layer 12.

The outer layer 12 has a first region 121, a second region 122 located on the base end side of the first region 121, a third region 123 located on the base end side of the second region 122, and a fourth region 124 located on the base end side of the third region 123. The third region 123 is more flexible than the fourth region 124, the second region 122 is more flexible than the third region 123, and the first region 121 is more flexible than the second region 122. With this configuration, the flexibility of the tube 10 gradually increases toward the tip, and during insertion into a blood vessel, the tube 10 can be inserted more safely into the blood vessel while ensuring sufficient pushability and torque transmission to the tip side.

Materials constituting the outer layer 12 include, for example, various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based, and one or a combination of two or more of these (polymer alloy, polymer blend, laminate, etc.) can be used.

The material of the inner layer 11 is preferably one that provides low friction at least in the portion that comes into contact with a device such as a treatment catheter or a guidewire when the device is inserted into the lumen 10H. This configuration allows the device inserted into the tube 10 to move in the longitudinal direction with less sliding resistance, improving operability. Specifically, the material of the inner layer 11 may be, for example, a fluorine-based resin material such as polytetrafluoroethylene (PTFE).

The reinforcing material layer 13 has multiple reinforcing wires that reinforce the tube 10. Examples of the reinforcing wires include those that are spiral or mesh shaped. The reinforcing wires are made of metal such as stainless steel. Specific examples include those in which stainless steel wires are flattened into a plate shape and then multiple pieces (8 to 32 of them) are used to form a spiral shape or braided (braided body) so that the radial thickness of the tube 10 is thin. It is preferable that the number of reinforcing wires is a multiple of 8 to provide balanced reinforcement in the tubular shape.

By making the reinforcing wire flat, it receives external stress evenly compared to an ellipse, and the physical properties become consistent.

Of the multiple reinforcing wires, in the cross-sectional view shown in Figure 2, the reinforcing material arranged on the inside is referred to as the reinforcing wire 14 arranged on the inside, and the reinforcing material arranged on the outside is referred to as the reinforcing wire 15 arranged on the outside (see Figures 3 and 4). In Figure 4, the reinforcing wires are 1-over-1, crossing every other line, but they may also be 2-over-2, crossing every other line, or 2-over-1, crossing two lines and one line.

In the catheter 1 according to this embodiment, when viewed in cross section in the longitudinal direction as shown in FIG. 2, an imaginary line L is drawn that intersects the reinforcing wire 14 arranged on the inside and the reinforcing wire 15 arranged on the outside. When the angle θ1 between the imaginary line L and the reinforcing wire 14 arranged on the inside and the angle θ2 between the imaginary line L and the reinforcing wire 15 arranged on the outside are defined as angles θ1 and θ2, respectively, the angles θ1 and θ2, which are in the same angular relationship, are different.

Here, the imaginary line L is not limited as long as it intersects with the reinforcing wire 14 arranged on the inside and the reinforcing wire 15 arranged on the outside. As an example, in FIG. 2, the imaginary line L is drawn in a direction perpendicular to the axial direction (horizontal direction in FIG. 2).

The difference between the angles θ1 and θ2 is not particularly limited, but is preferably 2 to 8°. Here, if the difference between the angles θ1 and θ2 is less than 2°, it is not preferable because the contact area with the resin in the tensile direction is small and the anchor cannot function. Also, if the difference between the angles θ1 and θ2 is more than 8°, it is not preferable because it may lead to exposure of the blade wire.

Here, for example, if the angles θ1 and θ2 are the same (in other words, the reinforcing wire 14 arranged on the inside and the reinforcing wire 15 arranged on the outside are parallel to each other), if the strength of the joint between the catheter hub and the tube (hub strength) is low, the joint may break, for example, when the guiding catheter gets stuck inside the body and a tensile load is applied.

In contrast, with the catheter 1 according to this embodiment, the alignment angles when a virtual line is drawn that intersects the reinforcing wire 14 arranged on the inside and the reinforcing wire 15 arranged on the outside are different, so compared to when the alignment angles are the same, the effect of the reinforcing wire as an anchor when the catheter 1 is pulled is improved, and the hub strength can be improved. From the above, it is possible to provide a catheter 1 with improved hub strength.

The number of layers constituting the tube 10 and the material of each layer may vary along the longitudinal direction of the tube 10. For example, in order to make the tip portion of the tube 10 more flexible, the number of layers may be reduced, a more flexible material may be used, or no reinforcing material may be placed in that portion.

Since the catheter 1 is inserted into the body while checking its position under X-ray fluoroscopy, it is preferable that an X-ray opaque material (X-ray contrast medium) is blended into the material constituting the outer layer 12. Examples of the X-ray opaque material that can be used include barium sulfate, bismuth oxide, and tungsten. Furthermore, the ratio of the X-ray opaque material blended into the material constituting the outer layer 12 is preferably 30 to 80 wt %.

In addition, such X-ray opaque material does not necessarily have to be present over the entire length of the tube 10, but may be present only in a part of the tube 10, for example, only the tip or only the tip tip 20.

The tip of the tube 10 is curved into a desired shape suitable for the site where the tip of the tube 10 is to be inserted, such as the left coronary artery or the right coronary artery. In particular, the tip is shaped to facilitate the operation of engaging the tip with the coronary artery port (engagement operation), or to more reliably maintain the state of engagement with the coronary artery port (engagement).

A tip tip 20 is connected to the tip of the tube 10. This tip tip 20 is made of a flexible material, and its tip is preferably rounded. By providing such a tip tip 20, it can be smoothly and safely run through curved, bent, and branched blood vessels. Examples of materials that can be used to make the tip tip 20 include various rubber materials such as natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, silicone rubber, fluororubber, and styrene-butadiene rubber, as well as various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based.

The material constituting the distal tip 20 may also contain an X-ray opaque material (X-ray contrast agent) as described above.

The length of the tip 20 is not particularly limited, but is usually preferably about 0.5 to 3 mm, and more preferably about 1 to 2 mm.

A hub 30 is attached (fixed) to the base end of the tube 10. This hub 30 has an inner cavity that communicates with the lumen 10H. This inner cavity has an inner diameter that is approximately equal to the inner diameter of the lumen 10H, and is continuous with the inner surface of the base end of the lumen 10H without creating any steps or the like.

From the hub 30, for example, long objects (linear objects) such as guide wires, catheters (e.g., balloon catheters for PTCA, catheters for carrying stents), endoscopes, ultrasound probes, and temperature sensors can be inserted or removed, and various liquids such as contrast agents (X-ray contrast agents), medicinal liquids, and saline can be injected. The hub 30 can also be connected to other devices, such as a Y-shaped branch connector.

The preferred dimensions of the tube 10 in this embodiment are explained below with reference to Figure 3.

The outer diameter D1 of the tube 10 is preferably 1.35 mm or more and 3 mm or less. If the outer diameter D1 is too large, the operability of inserting the tube 10 into the artery and running it through it may decrease, and the burden on the patient may increase.

The inner diameter d1 of the tube 10 is preferably 1.2 mm or more and 2.85 mm or less. If the inner diameter d1 is too small, the outer diameter of the treatment catheter or the like that can be inserted into the tube 10 will also be small, which is undesirable as it limits the range of choices for devices that can be inserted and used.

In the tube 10, the ratio of the inner diameter to the outer diameter, d1/D1, is 0.85 or more and 0.91 or less, preferably 0.87 or more and 0.91 or less. If the value of d1/D1 is too small, the wall thickness of the tube 10 will be thick and the inner diameter will be small, limiting the devices that can be introduced into the tube 10. If the value of d1/D1 is too large, the wall thickness of the tube 10 will not be sufficient, resulting in a weak backup force and reduced kink resistance during use.

The inner layer 11 is preferably 8 μm or more and 20 μm or less. It is desirable for it to be as thin as possible while still covering the inner surface of the tube 10 evenly.

As described above, the catheter 1 according to this embodiment is a catheter 1 in which the reinforcing wires 14, 15 are woven together, and when viewed in cross section in the longitudinal direction, the alignment angles when the imaginary line L is drawn intersecting the reinforcing wire 14 arranged on the inside and the reinforcing wire 15 arranged on the outside are different. With the catheter 1 configured in this manner, the alignment angles when the imaginary line L is drawn intersecting the reinforcing wire 14 arranged on the inside and the reinforcing wire 15 arranged on the outside are different, so that compared to when the alignment angles are the same, the effect of the reinforcing wire as an anchor when the catheter 1 is pulled is improved, and the hub strength can be improved. From the above, it is possible to provide a catheter 1 with improved hub strength.

The catheter 1 according to the present invention has been described above through the embodiments, but the present invention is not limited to the configurations described in the embodiments, and can be modified as appropriate based on the claims.

1 catheter,
10 tubes,
13 Reinforcement layer,
14 Reinforcing wire arranged on the inside;
15. Reinforcing wires arranged on the outside;
L virtual line,
θ1, θ2 angles.

Claims (3)

A catheter in which reinforcing wires are braided together,
In cross-sectional view along the long axis,
A catheter in which imaginary lines drawn intersecting an inner reinforcing wire and an outer reinforcing wire have different alignment angles. The catheter according to claim 1, wherein the difference in the alignment angle between the reinforcing wire and the virtual wire arranged on the inside and the reinforcing wire and the virtual wire arranged on the outside is 2 to 8°. The catheter according to claim 1 or 2, wherein at least one of the reinforcing wire arranged on the inside and the reinforcing wire arranged on the outside is a flat plate.