JP2023083212A - catheter - Google Patents

Abstract

To provide a catheter capable of freely transmitting a push-in force and a torque by an operation by a manipulator, from a hand side to a tip side.SOLUTION: A balloon catheter 1 comprises an outer shaft 5, an inner shaft 4 inserted into the outer shaft 5, a hypotube 6 connected to the rear end 4b of the inner shaft 4, and a distal end chip 8 formed at a junction of the distal end 2a of the balloon 2 and the distal end 4a of the inner shaft 4. A plurality of coils 3 are coiled between the inner shaft 4 and the outer shaft 5, and the coils 3 adjacent to each other are coiled in mutually reverse coiling.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to catheters such as balloon catheters used to dilate constricted or obstructed portions of blood vessels, digestive organs, and the like.

2. Description of the Related Art Conventionally, there is known a balloon catheter technique for dilating a constricted portion or an obstructed portion of a blood vessel, a digestive organ, etc. (hereinafter referred to as a blood vessel, etc.). A balloon catheter generally has a balloon at its distal end, and the balloon is communicated with a lumen formed between an inner shaft and an outer shaft. It is configured to be inflated to dilate a stricture or the like.

For example, in Cited Document 1, an inner shaft and an outer shaft provided coaxially with the inner shaft are provided. An invention has been proposed for a balloon catheter that is helically wound with a second reinforcing member to improve operability and kink resistance in body cavities.

JP-A-8-215312

By the way, when inserting a balloon catheter into a blood vessel or the like, an operator such as a doctor operates an operating section connected to the rear end portion of the inner shaft to insert the balloon catheter into the blood vessel or the like.

However, according to the balloon catheter of Cited Document 1, although the pushing force for pushing the balloon catheter in the axial direction is transmitted, the transmission of the rotational force (torque) for rotating the catheter around the axis is insufficient. There was a problem that fine manipulation using rotational force was not possible.

Accordingly, an object of the present disclosure is to provide a catheter that can be advanced while rotating within a body cavity by transmitting torque throughout the catheter.

In order to solve the above problems, the catheter of the present disclosure includes a hollow outer shaft, a hollow inner shaft inserted through the outer shaft, and a distal tip formed at the distal end of the inner shaft. and the outer shaft, a plurality of coils are radially superimposed and wound, and the coils adjacent to each other in the radial direction are wound in opposite directions.

According to the catheter of the present disclosure, torque applied to the rigid member can be smoothly transmitted from the rear end to the tip of the inner shaft and the outer shaft.

1(a) An overall view of a balloon catheter of Example 1, and (b) an enlarged cross-sectional view taken along the line AA. 3A and 3B are an enlarged plan view and an enlarged front view of a main part B; FIG. (a) CC line end view, (b) DD line end view. It is a schematic diagram explaining arrangement|positioning of a 1st joint part and a 2nd joint part. It is a schematic diagram explaining the winding state of a coil. FIG. 4A is a schematic diagram showing torque transmission states in (a) a conventional catheter and (b) a catheter of the present disclosure. FIG. 8A is an enlarged front view of a main part B of Embodiment 2, and FIG. 8B is an enlarged cross-sectional view taken along line EE. (a) An enlarged front view of a main portion B of Embodiment 2, and (b) an enlarged cross-sectional view taken along the line FF. FIG. 4 is a schematic diagram showing interactions between upper and lower coils; FIG. 4 is a schematic diagram showing interactions between upper and lower coils;

An embodiment in which the present disclosure is embodied in a balloon catheter will be described below with reference to the drawings. In the following description, the left side of FIG. 1A is the tip side (distal side) to be inserted into the body, and the right side is the rear end side (hand side, proximal side) operated by an operator such as a doctor. .

As shown in FIG. 1, a balloon catheter 1 includes a balloon 2 for dilating an obstructed part or the like, a distal tip 8 disposed at the distal end of the balloon catheter 1, an outer shaft 5, and an outer shaft 5 provided coaxially. In addition to the inner shaft 4, the connector 7 which is an operation unit operated by an operator such as a doctor, the hypotube 6 as a rigid member for transmitting the operation applied to the connector 7 to the inner shaft 4, and the hypotube 6 A coil 3 is provided for transmitting the generated torque to the outer shaft 5 and the inner shaft 4 . The balloon catheter 1 is used, for example, for treatment of blocked or constricted portions of blood vessels of the heart, and has a total length of about 1500 mm.

The outer shaft 5 and the inner shaft 4 are flexible cylindrical members made of a resin material. Inside the inner shaft 4, a space 11 is formed through which a guide wire 10 (see FIG. 3) is inserted. Polyamide, polyamide elastomer, polyolefin, polyester, polyester elastomer, or the like can be used as the resin material used for the outer shaft 5 and the inner shaft 4 .

The coil 3 is a single-wire coil made of one material, but may be a stranded-wire coil made by twisting a plurality of materials. A material used for the coil 3 may be stainless steel or a superelastic alloy such as a Ni—Ti alloy. Moreover, although the cross-sectional shape of the coil 3 is rectangular, it may be any shape such as a circle or an ellipse.

The hypotube 6 is a rigid cylindrical member. The hypotube 6 has an outer diameter of about 0.80 mm and an inner diameter of about 0.60 mm. The material of the hypotube 6 can be stainless steel or a superelastic alloy such as a Ni--Ti alloy.

A connector 7 is attached to the rear end 6b of the hypotube 6 for operating the balloon catheter 1 by an operator. Connected to the connector 7 is an indeflator (not shown) for supplying liquid such as a contrast medium and physiological saline.

The inner shaft 4 is inserted through the outer shaft 5 , and the hypotube 6 is connected to the rear end 4 b of the inner shaft 4 . A front end 5a of an outer shaft 5 is joined to a rear end 2b of the balloon 2. As shown in FIG. A distal tip 8 made of resin (polyurethane, polyurethane elastomer, etc.) is formed at the joint between the distal end 2a of the balloon 2 and the distal end 4a of the inner shaft 4. As shown in FIG. The distal tip 8 may be made of a resin that is more flexible than the resin forming the distal end portion 4 a of the inner shaft 4 . The distal tip 8 is a tapered cylindrical member whose outer diameter gradually decreases toward its distal end. The distal end portion of the distal tip 8 has an opening 8 a communicating with the space 11 of the inner shaft 4 .

A coil 3 is wound in a space 9 formed between the inner shaft 4 and the outer shaft 5 . In other words, the coil 3 is arranged in the space 9 while being spirally wound around the outer peripheral surface of the inner shaft 4 .

The front end 3a of the coil 3 is joined to the front tip 8, and the rear end 3b is joined to the front end 6a of the hypotube 6. As shown in FIG. Also, the space 9 communicates with the inside of the balloon 2 , and the liquid supplied from the indeflator is sent to the balloon 2 through the space 9 .

As shown in FIGS. 2 and 3 , the coil 3 and the inner shaft 4 are joined at a plurality of first joints 31 which are portions other than the distal tip 8 . Also, the coil 3 and the outer shaft 5 are joined at a plurality of second joint portions 32 which are portions other than the distal tip 8 .

The first joint portion 31 and the second joint portion 32 are provided at different positions on the coil 3 . Specifically, the second joint portion 32 is provided at a position shifted in the axis L direction from the first joint portion 31 . If the first joint portion 31 and the second joint portion 32 are provided at the same position, as shown in FIG. 4A, the liquid flow is obstructed. However, by shifting the second joint portion 32 and the first joint portion 31 in the direction of the axis L, as shown in FIG. 4B, the liquid can pass smoothly.

Here, the outer peripheral portion of the coil 3 is preferably in contact with at least a portion of the inner peripheral surface of the outer shaft 5 (state 1). Moreover, it is preferable that the inner peripheral portion of the coil 3 is in contact with at least a portion of the outer peripheral surface of the inner shaft 4 (state 2). At this time, either one or both of state 1 and state 2 can be established. By configuring in this way, the diameter of the balloon catheter 1 can be reduced, and the burden on the patient when it is inserted into a blood vessel or the like can be reduced.

As shown in FIG. 5, the coils 3 are wound with intervals. In other words, the coil 3 is loosely wound. By widening the interval d between the coil wires of the coil 3, a spiral flow path is secured, and the liquid can easily pass between the coil wires. For example, comparing FIG. 5(a) and FIG. 5(b), the distance between the coil wires is d1<d2, so the fluid flows more easily in FIG. 5(b) where the distance between the coil wires is wider.

Next, the movement of the balloon catheter 1 configured as described above when the operator operates the connector 7 and applies torque to the hypotube 6 will be described with reference to FIG.

As shown in FIG. 6( a ), in the conventional balloon catheter 1 , the coil is joined to the inner shaft 4 and the outer shaft 5 via joints (first and second joints 31 and 32 ) other than the distal tip 8 . 3 is not provided, torque is not sufficiently transmitted from the proximal side to the distal side. Therefore, although the hand side rotates, the rotation is difficult to be transmitted to the tip side.

On the other hand, as shown in FIG. 6B, in the balloon catheter 1 of the present disclosure, torque can be smoothly transmitted from the proximal side to the distal side via the coil 3 . A detailed description will be given below.

First, when torque is applied to the hypotube 6 , the torque is transmitted to the rear end 3 b of the coil 3 joined to the hypotube 6 . Since the coil 3 is spirally wound around the inner shaft 4 , torque is transmitted along the coil 3 from the rear end 3 b of the coil 3 toward the front end 3 a of the coil 3 .

At this time, since the coil 3 is joined to the inner shaft 4 at a plurality of first joints 31, the torque is generated at each of the first joints on the way from the rear end 3b of the coil 3 to the front end 3a of the coil 3. Via 31 torque is transmitted from the coil 3 to the inner shaft 4 .

In parallel with this, since the coil 3 is joined to the outer shaft 5 at a plurality of second joints 32, the torque is applied from the rear end 3b of the coil 3 to the front end 3a of the coil 3. Torque is transmitted from the coil 3 to the outer shaft 5 via the joint 32 .

Therefore, according to the balloon catheter 1 of this embodiment, the torque transmitted from the hypotube 6 is smoothly applied to the entire area of the inner shaft 4 and the outer shaft 5 via the first and second joints 31 and 32 of the coil 3. Since it is transmitted, the operator's pushing operation and rotating operation can be delicately and accurately transmitted from the hand of the catheter to the distal end, and the balloon 2 can be moved to the desired position while reducing the burden on the patient's body. be able to.

A balloon catheter 1 of Example 2 will be described with reference to FIGS. In addition, in Example 2, the same code|symbol is attached|subjected to drawing about the same or similar component as Example 1, and the overlapping description is abbreviate|omitted. In addition, regarding the winding direction of the coil, the forward direction is indicated as "Z", and the reverse direction of the Z direction is indicated as "S".

In Example 2, the balloon catheter 1 includes a hollow outer shaft 5, a hollow inner shaft 4 inserted through the outer shaft 5, and a distal tip 8 formed at the distal end 4a of the inner shaft 4, A plurality of coils 3 are radially superimposed and wound between the inner shaft 4 and the outer shaft 5, and the coils 3 adjacent to each other in the radial direction are wound in opposite directions. Specific examples are shown below.

As shown in FIG. 7, the plurality of coils 3 can be composed of two layers of coils 3 (upper layer coil 3-1, lower layer coil 3-3). The coils 3-1 and 3-3 are wound in reverse. For example, the winding directions of the coils 3-1 and 3-3 can be "Z·S" or "S·Z".

At this time, either one or both of the coils 3-1 and 3-3 can be provided in a so-called "sparse winding", in which they are wound with a gap in the axial direction. Either one or both of the coils 3-1 and 3-3 may be loosely wound only for a portion of the total coil length. A flow path for physiological saline or the like can be ensured by loosely winding. Further, among the plurality of coils 3-1 and 3-3, the lower layer coil 3-3 can be wound more tightly than the upper layer coil 3-1. By tightly winding the lower layer side, the rigidity inside the coil can be increased.

As shown in FIG. 8, the plurality of coils 3 can be composed of three layers of coils 3 (upper layer coil 3-1, middle layer coil 3-2, and lower layer coil 3-3). The coils 3-1 to 3-3 are alternately wound in reverse. For example, the winding directions of the coils 3-1 to 3-3 can be "Z.S.Z" or "S.Z.S."

At this time, any one or more of the coils 3-1 to 3-3 or all of them can be loosely wound. Any one or more of the coils 3-1 to 3-3, or all of the coils 3-3 may be loosely wound only for a portion of the total coil length. A flow path for physiological saline or the like can be ensured by loosely winding. Among the plurality of coils 3-1 to 3-3, either one or both of the middle-layer coil 3-2 and the lower-layer coil 3-3 can be wound more tightly than the upper-layer coil 3-1. For example, if the dense windings of the coils 3-1 to 3-3 are respectively m1, m2, and m3, then "m1<m2≦m3", "m1<m3<m2", etc. can be obtained. By tightly winding the coils 3 in the middle and lower layers, the rigidity inside the coils can be increased.

Next, the movement of the balloon catheter 1 configured as in Example 2 when the operator manipulates the connector 7 and applies torque to the hypotube 6 will be described with reference to FIGS.

As shown in FIG. 9(a), when the operator applies torque in the same direction as the winding direction of the lower coil 3-3, the coil 3-1 loosens and the pitch (interval) increases, and the coil 3-3 It shrinks and the pitch narrows. Further, as shown in FIG. 9(b), the diameter of the coil 3-1 is expanded and the diameter of the coil 3-3 is reduced. At this time, the diameter expansion of the coil 3-1 is restricted by the outer shaft 5, and the diameter reduction of the coil 3-3 is restricted by the inner shaft 4. FIG. These interactions generate a strong torque.

On the other hand, as shown in FIG. 10(a), when the operator applies torque in the same direction as the winding direction of the upper layer coil 3-1, the coil 3-1 shrinks and the pitch narrows, and the coil 3-3 loosens. spreads the pitch. Also, as shown in FIG. 10(b), the coil 3-1 is reduced in diameter and the coil 3-3 is expanded in diameter. At this time, the coil 3-1 is restricted in diameter reduction by the coil 3-3, and the coil 3-3 is restricted in diameter expansion by the coil 3-1. These interactions generate a strong torque. Even when the coils 3 are provided in three layers, the coils 3-1 to 3-3 are mutually restricted in diameter expansion or diameter contraction, and strong torque is generated by the interaction of these.

Therefore, according to the balloon catheter 1 of Example 2, the coils 3 are composed of a plurality of coils 3, and the plurality of coils 3 are configured such that the adjacent coils are reversely wound. can interfere and generate strong torque. Moreover, since at least one coil 3 among the plurality of coils 3 is loosely wound, physiological saline or the like can pass through smoothly. Furthermore, since the coil 3-2 in the middle layer and the coil 3-3 in the lower layer are more loosely wound than the coil 3-1 in the upper layer, the rigidity inside the coil 3 is increased, and the rigidity balance of the entire coil 3 can be adjusted.

It should be noted that the present disclosure is not limited to the above-described embodiments, and it is also possible to change the shape and configuration of each part as appropriate without departing from the gist of the present disclosure.
For example, the hypotube 6 as a rigid member may be omitted. In this case, the connector 7 functions as a rigid member. That is, the inner shaft 4 and the outer shaft 5 are extended to the connector 7 and the rear end of the coil 3 is joined to the connector 7 .
The joining may be joining by heat welding. Also, bonding may be performed by applying an adhesive such as an epoxy adhesive or a cyanoacrylate adhesive.
At least one of the coils 3 may be a stranded coil in which a plurality of strands are woven. At least one of the coils 3 may be a single wire coil.
In addition, in Examples 1 and 2, a balloon catheter was used as an example, but the present invention can also be applied to various catheters such as penetrating catheters without balloons, guiding catheters, and microcatheters.

At least one of the plurality of coils 3 may be joined to the inner shaft 4 or the outer shaft 5 that is adjacent in the radial direction over half or more of the entire area from the distal end 3a to the proximal end 3b. For example, the lower layer coil 3-3 directly wound around the inner shaft 4 in FIG. 7 may be joined to the inner shaft 4 in more than half of the area from the distal end 3a to the proximal end 3b. Further, the coil 3-3 in the lower layer may be joined to the inner shaft 4 over the entire area from the distal end 3a to the proximal end 3b.
Similarly, the upper coil 3-1 may be joined to the outer shaft 5 over half or more of the area from the distal end 3a to the proximal end 3b. Further, the upper coil 3-1 may be joined to the outer shaft 5 over the entire region from the distal end 3a to the proximal end 3b.

REFERENCE SIGNS LIST 1 balloon catheter 2 balloon 3 coil 4 inner shaft 5 outer shaft 6 hypotube 7 connector 8 distal tip 9 space 10 guide wire 31 first junction 32 second junction

Claims (7)

A hollow outer shaft, a hollow inner shaft inserted through the outer shaft, and a distal tip formed at the distal end of the inner shaft,
A plurality of coils are radially superimposed and wound between the inner shaft and the outer shaft,
A catheter in which radially adjacent coils are wound in opposite directions. 2. The catheter according to claim 1, wherein at least one coil among the plurality of coils is wound with a gap in the axial direction. 3. The coil according to claim 1, wherein at least one of the plurality of coils is joined to the inner shaft or the outer shaft radially adjacent to the inner shaft or the outer shaft over a length of half or more of the entire area from the distal end to the proximal end. catheter. The coil and the inner shaft are also joined at a portion other than the distal tip,
The catheter according to claim 1 or 2, wherein the coil and the outer shaft are joined at a portion other than the joining portion of the coil and the inner shaft. The coil is joined to the outer shaft at a plurality of first joints,
The coil is joined to the inner shaft at a plurality of second joints,
5. The catheter according to claim 4, wherein the first joint and the second joint are provided at different positions on the coil. 6. The catheter according to claim 5, wherein the second joint is axially offset from the first joint. 3. The catheter according to claim 1 or 2, wherein the plurality of coils consist of three layers of coils.

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