WO2025047651A1 - Catheter - Google Patents

Abstract

To provide a catheter that has high insertability in both a hardened living body lumen and a curved living body lumen, and that is easily delivered. This catheter (1) has: a shaft (10) that has a longitudinal direction (x1) and a circumferential direction (z1) around the outer circumference in a cross-section perpendicular to the longitudinal direction (x1), and that is provided with a lumen extending in the longitudinal direction (x1); and a core material (20) that is disposed in the lumen of the shaft (10). The shaft (10) has an outer resin tube (11) and an inner resin tube (12) that is disposed in the lumen of the outer resin tube (11). The shaft (10) has a first region (R1) positioned further to the distal side than the distal end (20d) of the core material (20), and a second region (R2) positioned further to the distal side than the first region (R1). In the first region (R1), the longitudinal component of the molecular orientation of the inner resin tube (12) is greater than the longitudinal component of the molecular orientation of the outer resin tube (11).

Description

catheter

The present invention relates to a catheter.

As a minimally invasive treatment for lesions in blood vessels or organs that does not involve open surgery, catheters are widely used to treat lesions such as stenosis and administer contrast agents or drugs into blood vessels, as well as for examinations and procedures.

It is known that various diseases occur when stenosis occurs in blood vessels, which are the channels through which blood circulates in the body, causing blood circulation to slow down. In particular, stenosis in the coronary arteries that supply blood to the heart can lead to serious diseases such as angina pectoris and myocardial infarction. One method of treating such stenosis in blood vessels is angioplasty (PTA, PTCA, etc.), which uses a balloon catheter or stent to expand the stenosis. Angioplasty is a minimally invasive therapy that does not require open chest surgery like bypass surgery. Angioplasty is also used to treat stenosis that occurs in shunts for dialysis.

In addition, bile ducts can be blocked by gallstones or tumors, or the flow of bile can be impeded within the bile duct, causing bile to stagnate in the bile duct and resulting in a bacterial infection. Bacterial infection of the bile can lead to cholangitis, and if bile containing bacteria passes through the liver and enters the bloodstream throughout the body, it can cause sepsis. In such cases, a procedure is required to drain the bile from the bile duct, and a catheter is inserted into the bile duct to perform percutaneous transhepatic biliary drainage (PTCD) or endoscopic biliary drainage (ERBD), etc.

Patent Document 1 describes a balloon catheter that can transmit a pushing force transmitted from the proximal side to the distal side. The balloon catheter includes a balloon, a cylindrical outer shaft that constitutes an expansion lumen that supplies a fluid for expanding the balloon, an opening control section that has a control hole that communicates with the expansion lumen, a core wire that has a pressing section that can abut against the control hole of the opening control section, an inner shaft that has a guidewire lumen therein for inserting a guidewire, a tip guidewire port formed at the distal end of the inner shaft, and a rear guidewire port formed at the proximal end of the inner shaft, and it is disclosed that the rear guidewire port is formed in the opening control section of the outer shaft.

Patent document 2 describes a balloon catheter that can be located or identified during use. The balloon catheter includes a shaft, an inflatable balloon attached to the shaft and having an interior, and at least three radiopaque markings in the interior of the balloon spaced apart along a longitudinal axis of the catheter, and a first distance that separates a first radiopaque marking from an adjacent second radiopaque marking is different from a second distance that separates the second radiopaque marking from an adjacent third radiopaque marking.

Patent document 3 describes a balloon catheter that has excellent pushability and can prevent kinking. The balloon catheter includes an outer shaft, a balloon connected to the tip of the outer shaft, a hub connected to the rear end of the outer shaft, a resin tube that forms a guidewire lumen, the rear end of which opens as a guidewire port on the side of the outer shaft, an inner tube whose tip is fixed to the tip of the balloon and whose tip opens, and a core wire having a straight portion and a reduced diameter portion, the core wire being fixed to the inner surface of the outer shaft, the straight portion of the core wire being press-fitted between the inner surface of the outer shaft and the outer surface of the inner tube, and the cross section of the outer shaft at the portion where the straight portion of the core wire is press-fitted is deformed into an elliptical shape.

JP 2015-013207 A Special Publication No. 2015-527123 JP 2016-083279 A

When calcification progresses in blood vessels, the lumen of the body may harden. There is a problem in that it is difficult to deliver a catheter through a hardened lumen of the body. In addition, if the rigidity of the catheter is increased to improve the catheter's insertability, the catheter becomes difficult to bend, and there is also a problem in that it is difficult to insert the catheter into a curved lumen of the body. None of the catheters described in Patent Documents 1 to 3 have sufficient insertability through both hardened and curved lumen of the body, and there is room for improvement.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a catheter that has high insertability in both hardened and curved biological lumens and is easy to deliver.

A catheter according to an embodiment of the present invention that can solve the above problems is as follows.
[1] A shaft having a longitudinal direction and a circumferential direction along an outer periphery in a cross section perpendicular to the longitudinal direction, and having an inner cavity extending in the longitudinal direction;
a core disposed in the lumen of the shaft;
The shaft includes an outer resin tube and an inner resin tube disposed in an inner cavity of the outer resin tube,
The shaft has a first region located distal to a distal end of the core material and a second region located distal to the first region,
A catheter, wherein in the first region, the longitudinal component of the molecular orientation of the inner resin tube is greater than the longitudinal component of the molecular orientation of the outer resin tube.
[2] A catheter as described in [1], wherein the outer diameter of the outer resin tube in the second region is smaller than the outer diameter of the outer resin tube in the first region.
[3] A catheter described in [1] or [2], wherein the longitudinal component of the molecular orientation of the outer resin tube in the second region is greater than the longitudinal component of the molecular orientation of the outer resin tube in the first region.
[4] A catheter described in any of [1] to [3], wherein in the second region, the main orientation direction of the molecular orientation of the outer resin tube and the main orientation direction of the molecular orientation of the inner resin tube are the longitudinal direction.
[5] A catheter according to any one of [1] to [4], wherein the main orientation direction of the molecules of the inner resin tube is the longitudinal direction.
[6] A catheter described in any of [1] to [5], wherein in the second region, the longitudinal component of the molecular orientation of the outer resin tube is greater than the longitudinal component of the molecular orientation of the inner resin tube.
[7] An opening is provided in a peripheral wall of the outer resin tube, through which an outside of the outer resin tube communicates with an inner cavity of the inner resin tube,
The catheter according to any one of [1] to [6], wherein the opening is located proximal to the distal end of the core material.
[8] The catheter described in any one of [1] to [7], further comprising a balloon disposed in the distal portion of the outer resin tube.
[9] The shaft has a fluid supply tube that is in communication with the inner cavity of the balloon and through which a fluid is supplied;
the fluid supply tube is disposed inside the outer resin tube and outside the inner resin tube,
The catheter according to claim 8, wherein the cross-sectional shape of the lumen of the fluid supply tube in a cross section perpendicular to the longitudinal direction is elliptical.

In the above catheter, the shaft has a first region located distal to the distal end of the core material and a second region located distal to the first region, and in the first region, the longitudinal component of the molecular orientation of the inner resin tube is greater than the longitudinal component of the molecular orientation of the outer resin tube, thereby increasing the rigidity of the inner resin tube in the first region and increasing the flexibility of the outer resin tube. As a result, it is possible to achieve both the rigidity of the inner resin tube and the flexibility of the outer resin tube in the first region, which increases the insertability in both hardened and curved biological lumens and makes it easier to deliver the catheter.

1 illustrates a side view of a catheter according to an embodiment of the present invention. 2 illustrates a longitudinal cross-sectional view of the catheter shown in FIG. 1. 3 shows a cross-sectional view of the catheter shown in FIG. 1 taken along line III-III. 4 shows a cross-sectional view of the catheter shown in FIG. 1 taken along line IV-IV. 4 shows a cross-sectional view along the longitudinal direction of a core material according to another embodiment of the present invention. 6A and 6B are schematic diagrams showing a method for measuring the breaking elongation of an outer resin tube and an inner resin tube, in which FIG. 6A shows a schematic diagram at the start of tension and FIG. 6B shows a schematic diagram at break. 4 illustrates a cross-sectional view showing a modified example of FIG. 3. 5 is a cross-sectional view showing a modified example of FIG. 4 . 1 shows a schematic diagram of an evaluation circuit used to evaluate the insertability of a catheter.

The present invention will be described below based on the embodiments, but the present invention is of course not limited to the embodiments below, and can of course be implemented with appropriate modifications within the scope of the intent described above and below, all of which are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to contributing to an understanding of the features of the present invention.

A catheter according to an embodiment of the present invention has a shaft with a longitudinal direction and a circumferential direction along the outer periphery in a cross section perpendicular to the longitudinal direction, an inner lumen extending in the longitudinal direction, and a core material disposed in the inner lumen of the shaft, the shaft having an outer resin tube and an inner resin tube disposed in the inner lumen of the outer resin tube, the shaft having a first region located distal to the distal end of the core material and a second region located distal to the first region, and in the first region, the longitudinal component of the molecular orientation of the inner resin tube is greater than the longitudinal component of the molecular orientation of the outer resin tube.

Below, a catheter according to an embodiment of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a side view of a catheter according to an embodiment of the present invention, and Figure 2 is a cross-sectional view along the longitudinal direction of the catheter. Figure 3 is a cross-sectional view of the catheter taken along line III-III, which is a cross-sectional view perpendicular to the longitudinal direction on the distal side of the opening. Figure 4 is a cross-sectional view of the catheter taken along line IV-IV, which is a cross-sectional view perpendicular to the longitudinal direction on the proximal side of the opening.

As shown in Figures 1 and 2, the catheter 1 has a longitudinal direction x1 and a circumferential direction z1 along the outer periphery in a cross section perpendicular to the longitudinal direction x1, and includes a shaft 10 with an inner cavity extending in the longitudinal direction x1, and a core material 20 disposed in the inner cavity of the shaft 10.

The shaft 10 has a longitudinal direction x1, a radial direction y1 connecting the centroid of the outer edge of the shaft 10 to a point on the outer edge in a cross section perpendicular to the longitudinal direction x1, and a circumferential direction z1 along the outer circumference of the shaft 10 in a cross section perpendicular to the longitudinal direction x1. The radial direction y1 and the circumferential direction z1 are directions perpendicular to the longitudinal direction x1. In this specification, the direction toward the user's hand of the catheter 1 is referred to as the proximal side, and the opposite side to the proximal side, i.e., the direction toward the subject of treatment, is referred to as the distal side. The direction from the proximal side to the distal side of the shaft 10 is referred to as the longitudinal direction x1.

Members and parts other than the shaft 10 also have longitudinal, radial, and circumferential directions, which may or may not be the same as the longitudinal direction x1, radial direction y1, and circumferential direction z1 of the shaft 10. However, for ease of understanding, this specification will be described as assuming that all members and parts have the same longitudinal, radial, and circumferential directions as the longitudinal direction x1, radial direction y1, and circumferential direction z1 of the shaft 10.

The shaft 10 has an inner cavity extending in the longitudinal direction x1. The shaft 10 has a distal end 10d and a proximal end 10p in the longitudinal direction x1.

The shaft 10 has an outer resin tube 11 and an inner resin tube 12 disposed in the inner cavity of the outer resin tube 11. In other words, the shaft 10 has an outer resin tube 11 having an inner cavity extending in the longitudinal direction x1, and an inner resin tube 12 disposed in the inner cavity of the outer resin tube 11 and having an inner cavity extending in the longitudinal direction x1.

The outer resin tube 11 has a distal end 11d and a proximal end 11p in the longitudinal direction x1. The outer resin tube 11 may have an opening at at least one of the distal end 11d and the proximal end 11p. When the distal end 11d of the outer resin tube 11 has an opening, it is preferable that the opening at the distal end 11d of the outer resin tube 11 communicates between the inner cavity of the outer resin tube 11 and the outside of the outer resin tube 11. When the proximal end 11p of the outer resin tube 11 has an opening, it is preferable that the opening at the proximal end 11p of the outer resin tube 11 communicates between the inner cavity of the outer resin tube 11 and the outside of the outer resin tube 11.

The material constituting the outer resin tube 11 may be, for example, a polyolefin resin such as polyethylene or polypropylene, a polyamide resin such as nylon, a polyester resin such as PET, an aromatic polyetherketone resin such as PEEK, a polyetherpolyamide resin, a polyurethane resin, a polyimide resin, a fluorine resin such as PTFE, PFA, or ETFE, or a synthetic resin such as polyvinyl chloride resin. Among these, the material constituting the outer resin tube 11 is preferably a polyamide resin, and more preferably a polyamide elastomer. By using a polyamide elastomer as the material constituting the outer resin tube 11, the outer surface of the outer resin tube 11 has good slipperiness and the outer resin tube 11 has appropriate rigidity. Therefore, the catheter 1 can be easily inserted into a blood vessel and easily delivered.

The outer resin tube 11 may have a single-layer structure or a multi-layer structure. When the outer resin tube 11 has a multi-layer structure, for example, the outer resin tube 11 may have a structure in which a middle layer of the resin tube constituting the outer resin tube 11 is made of a metal braid such as stainless steel, carbon steel, or nickel-titanium alloy.

The inner resin tube 12 has a distal end 12d and a proximal end 12p in the longitudinal direction x1. The inner resin tube 12 may have an opening at at least one of the distal end 12d and the proximal end 12p. When the distal end 12d of the inner resin tube 12 has an opening, it is preferable that the opening at the distal end 12d of the inner resin tube 12 communicates between the inner cavity of the inner resin tube 12 and the outside of the inner resin tube 12. When the proximal end 12p of the inner resin tube 12 has an opening, it is preferable that the opening at the proximal end 12p of the inner resin tube 12 communicates between the inner cavity of the inner resin tube 12 and the outside of the inner resin tube 12.

The material constituting the inner resin tube 12 may be the synthetic resins listed as the material constituting the outer resin tube 11 described above. In particular, the material constituting the inner resin tube 12 is preferably a polyamide resin, and more preferably a polyamide elastomer. By using a polyamide elastomer as the material constituting the inner resin tube 12, the slipperiness of the surface of the inner resin tube 12 can be increased, and appropriate rigidity can be imparted to the inner resin tube 12. As a result, it becomes easier to insert an object such as a guidewire into the inner resin tube 12, and it becomes easier to insert the catheter 1 into a blood vessel.

The inner resin tube 12 may have a single layer structure or a multi-layer structure. When the inner resin tube 12 has a multi-layer structure, it may have a structure in which multiple layers made of synthetic resins, etc., listed as materials constituting the outer resin tube 11 described above, are combined. Furthermore, the inner resin tube 12 may have a structure in which a middle layer of the resin tube constituting the inner resin tube 12 is made of a metal braid such as stainless steel, carbon steel, or nickel-titanium alloy.

The material constituting the inner resin tube 12 may be different from the material constituting the outer resin tube 11, but it is preferable that they are the same. By using the same material constituting the inner resin tube 12 and the outer resin tube 11, it becomes easier to increase the bonding strength between the outer resin tube 11 and the inner resin tube 12 when the inner resin tube 12 is placed in the inner cavity of the outer resin tube 11 and the outer resin tube 11 and the inner resin tube 12 are fixed together.

Methods for joining the outer resin tube 11 and the inner resin tube 12 include, for example, bonding with an adhesive, welding, attaching a ring-shaped member or the like to the overlapping portion of the outer resin tube 11 and the inner resin tube 12 and crimping the tube, etc. Among these, it is preferable that the outer resin tube 11 and the inner resin tube 12 are joined by welding. By joining the outer resin tube 11 and the inner resin tube 12 by welding, the joining strength between the outer resin tube 11 and the inner resin tube 12 is easily increased, and the joining between the outer resin tube 11 and the inner resin tube 12 can be made difficult to be released.

As shown in FIG. 1, a hub 5 may be provided on the proximal side of the shaft 10. In addition, when supplying fluid to the inner cavity of the shaft 10, the hub 5 may be provided with a fluid injection section 6 that is connected to a flow path of the fluid supplied to the inner cavity of the shaft 10.

The shaft 10 and the hub 5 can be joined by, for example, bonding with an adhesive, welding, etc. Among these, it is preferable that the shaft 10 and the hub 5 are joined by adhesion. By joining the shaft 10 and the hub 5 by adhesion, when the materials constituting the shaft 10 and the hub 5 are different, for example, when the shaft 10 is composed of a highly flexible material and the hub 5 is composed of a highly rigid material, it is easier to increase the bonding strength between the shaft 10 and the hub 5, and the bond between the shaft 10 and the hub 5 is less likely to come undone, thereby improving the durability of the catheter 1.

The core material 20 is disposed in the inner cavity of the shaft 10. By disposing the core material 20 in the inner cavity of the shaft 10, the rigidity of the shaft 10 can be increased, and the insertability of the catheter 1 can be improved. In addition, force applied to the shaft 10 from the proximal side of the catheter 1 can be easily transmitted through the core material 20 to the distal side of the shaft 10, improving the operability of the catheter 1.

The core material 20 may have a hollow structure, and is preferably a tube or pipe having a cylindrical structure, a coil formed by winding one or more wires in a spiral shape, or a combination of these. By configuring the core material 20 to have a hollow structure, the rigidity of the shaft 10 can be increased while ensuring appropriate flexibility, making it easier to deliver the catheter 1 to the treatment target site even in a curved internal lumen such as a blood vessel. The core material 20 may also have a solid structure such as a wire. By configuring the core material 20 to have a solid structure, the rigidity of the shaft 10 can be increased, making it easier to insert the catheter 1 into an internal lumen such as a blood vessel.

The core material 20 is preferably a linear member of a single wire or a twisted wire. The core material 20 may be a wire made of a metal wire such as stainless steel, carbon steel, or nickel-titanium alloy, or a wire made of a synthetic resin such as a polyolefin resin such as polyethylene or polypropylene, a polyamide resin such as nylon, a polyester resin such as PET, an aromatic polyether ketone resin such as PEEK, a polyether polyamide resin, a polyurethane resin, a polyimide resin, a fluorine resin such as PTFE, PFA, or ETFE, or a polyvinyl chloride resin. The core material 20 may be a combination of a metal material and a synthetic resin material, and may be, for example, a braid of a metal wire and a synthetic resin wire, or a metal wire coated with a synthetic resin. The material constituting the core material 20 is preferably a metal wire, and more preferably stainless steel. The core material 20 is made of a metal wire, which increases the strength of the core material 20 and makes it less likely to break or deform even if the core material 20 is repeatedly bent.

The core material 20 is preferably flexible. The flexibility of the core material 20 allows the core material 20 to be deformed to conform to the shape of a lumen in the body, such as a blood vessel, and also makes it easier for the catheter 1 to deform to conform to the shape of a curved lumen in the body. In addition, in order to maintain the shape of the core material 20, it is preferable that the core material 20 be elastic.

In order to make the catheter 1 easier to deform on the distal side of the catheter 1, it is preferable that the core material 20 has a portion whose rigidity decreases from the proximal side to the distal side, and it is even more preferable that at least a portion of the core material 20 in the longitudinal direction has a continuously decreasing rigidity from the proximal side to the distal side.

It is preferable that the core material 20 has at least a portion where the outer diameter of the core material 20, i.e., the thickness of the core material 20, tapers from the proximal side to the distal side. By having at least a portion where the thickness of the core material 20 tapers from the proximal side to the distal side, the force applied to the shaft 10 from the proximal side of the catheter 1 is easily transmitted to the distal side of the shaft 10, and the insertability of the catheter 1 can be improved. In addition, by having a portion where the thickness of the core material 20 tapers, the cross-sectional area occupied by the core material 20 in the lumen of the shaft 10 can be reduced, making it possible to reduce the diameter of the shaft 10 and ensure the width of the lumen of the shaft 10.

As shown in FIG. 2, the core material 20 has a large diameter portion on the proximal side where the core material 20 is thick, and a small diameter portion on the distal side where the core material 20 is thin, and more preferably has a tapered portion between the large diameter portion and the small diameter portion where the core material 20 becomes thinner from the proximal side to the distal side. By having the core material 20 configured to have a large diameter portion, a small diameter portion, and a tapered portion, the difference in rigidity in the longitudinal direction x1 of the core material 20 is less likely to become large. As a result, it is possible to reduce the rigidity step in the shaft 10 and prevent kinking.

Figure 5 is a cross-sectional view along the longitudinal direction of the core material 20 in another embodiment. As shown in Figure 5, the core material 20 has a large diameter portion on the proximal side where the core material 20 is thick, a small diameter portion on the distal side where the core material 20 is thin, and a transition portion between the large diameter portion and the small diameter portion. In the cross-sectional view along the longitudinal direction x1, it is also preferable that the transition portion has a tapered shape on one side with the central axis extending in the extension direction of the core material 20 as a boundary, and the other side with the central axis as a boundary is parallel to the extension direction of the core material 20. In other words, in the cross-sectional view along the longitudinal direction x1, it is preferable that the transition portion of the core material 20 has a so-called one-sided tapered shape. Since the core material 20 has a large diameter portion, a small diameter portion, and a transition portion, the force applied to the proximal side of the catheter 1 is easily transmitted to the tip side by the core material 20. In addition, because the core material 20 has a transition section with one side tapered and the other side parallel to the extension direction of the core material 20, the volume occupied by the distal end of the core material 20 in the inner cavity of the shaft 10 can be reduced, and space can be secured in the inner cavity of the shaft 10 to place other items such as tubes.

The cross-sectional shape of the core material 20 can be, for example, a circle, an oval, a polygon, a star, a crescent, a fan, or a combination of these. Note that oval shapes include ellipses, egg shapes, and rounded rectangular shapes. The cross-sectional shape of the core material 20 refers to the shape of a cross section perpendicular to the longitudinal direction when the core material 20 is in a straight state.

The proximal end 20p of the core material 20 is preferably located closer to the proximal side than the proximal end 11p of the outer resin tube 11. By having the proximal end 20p of the core material 20 located closer to the proximal side than the proximal end 11p of the outer resin tube 11, the rigidity of the shaft 10 can be increased on the proximal side of the catheter 1.

The proximal end of the core material 20 is preferably fixed to the hub 5. By fixing the proximal end of the core material 20 to the hub 5, the fixing strength of the core material 20 is increased, and the core material 20 is less likely to move in the longitudinal direction x1 even when the shaft 10 is curved. Methods for fixing the proximal end of the core material 20 to the hub 5 include, for example, adhesion with an adhesive, fitting, etc.

The shaft 10 has a first region R1 located distal to the distal end 20d of the core material 20, and a second region R2 located distal to the first region R1.

In the first region R1, the longitudinal component of the molecular orientation of the inner resin tube 12 is greater than the longitudinal component of the molecular orientation of the outer resin tube 11. In other words, in the first region R1, the longitudinal component of the molecular orientation of the resin constituting the inner resin tube 12 is greater than the longitudinal component of the molecular orientation of the resin constituting the outer resin tube 11. In the shaft 10, when the longitudinal component of the molecular orientation of the resin constituting the resin tube becomes greater, the resin tube tends to become stiffer and harder. Since the longitudinal component of the molecular orientation of the inner resin tube 12 is greater than the longitudinal component of the molecular orientation of the outer resin tube 11 in the first region R1, a highly rigid inner resin tube 12 and a highly flexible outer resin tube 11 are present in the portion distal to the portion where the core material 20 is disposed in the inner cavity of the shaft 10. As a result, the core material 20 increases the rigidity of the shaft 10 proximal to the first region R1, making it easier to transmit force applied from the proximal side to the tip of the shaft 10 even in hard blood vessels with advanced calcification, improving insertion, while the first region R1 achieves both the rigidity of the inner resin tube 12 and the flexibility of the outer resin tube 11, making it easier to insert the catheter 1 into curved blood vessels, etc.

The method for measuring the molecular orientation of the outer resin tube 11 and the inner resin tube 12 is described below.

The molecular orientation of the outer resin tube 11 and the inner resin tube 12 can be measured by determining the breaking elongation of the outer resin tube 11 and the inner resin tube 12. As shown in Figures 6(a) and 6(b), both ends of the outer resin tube 11 or the inner resin tube 12 are held by the chucks of a tensile tester, and the breaking elongation is measured when the outer resin tube 11 or the inner resin tube 12 is pulled in the longitudinal direction until it breaks. The breaking elongation is measured under the conditions of a chuck distance of 25 mm and a pulling speed of 500 mm/min. The breaking elongation can be calculated by the following formula, and is the ratio of the chuck distance L2 at break shown in Figure 6(b) to the chuck distance L1 at the start of pulling shown in Figure 6(a).
Breaking elongation rate = (chuck distance L2 at break - chuck distance L1 at start of tension) / chuck distance L1 at start of tension

The smaller the breaking elongation rate, the greater the longitudinal component of the molecular orientation, and the greater the breaking elongation rate, the less the longitudinal component of the molecular orientation. In other words, in the first region R1, if the breaking elongation rate of the inner resin tube 12 is smaller than that of the outer resin tube 11, it can be determined that the longitudinal component of the molecular orientation of the inner resin tube 12 is greater than that of the outer resin tube 11. This is thought to be because if there is a large longitudinal component of the molecular orientation, the strength of the resin in the longitudinal direction increases, making it more difficult to elongate, and the breaking elongation rate decreases.

In the first region R1, the breaking elongation of the outer resin tube 11 is preferably 1.1 times or more than the breaking elongation of the inner resin tube 12, more preferably 1.2 times or more, even more preferably 1.3 times or more, and even more preferably 1.5 times or more. By setting the lower limit of the ratio of the breaking elongation of the outer resin tube 11 to the breaking elongation of the inner resin tube 12 in the first region R1 to the above range, the rigidity of the resin tube in the shaft 10 in the first region R1 is increased and becomes hard, making the shaft 10 less likely to bend excessively. As a result, the force applied from the hand side is easily transmitted to the tip of the shaft 10, and the insertability of the catheter 1 can be improved. In addition, in the first region R1, the breaking elongation of the outer resin tube 11 is preferably 4 times or less than the breaking elongation of the inner resin tube 12, more preferably 3 times or less, and even more preferably 2 times or less. By setting the upper limit of the ratio between the breaking elongation rate of the outer resin tube 11 and the breaking elongation rate of the inner resin tube 12 in the first region R1 within the above range, the shaft 10 becomes more easily deformed and bent to fit the internal lumen of the body, making it easier to improve the flexibility of the catheter 1.

In order to make the longitudinal component of the molecular orientation of the inner resin tube 12 greater than the longitudinal component of the molecular orientation of the outer resin tube 11 in the first region R1, for example, the inner resin tube 12 may be stretched at least in the portion that will become the first region R1, while the outer resin tube 11 may not be stretched, or the inner resin tube 12 may be manufactured using a material or manufacturing method that makes it easier for the molecular orientation to be aligned longitudinally than the outer resin tube 11 in at least the portion that will become the first region R1.

It is preferable that at least a portion of the outer resin tube 11 and at least a portion of the inner resin tube 12 have been subjected to a stretching process. It is also more preferable that the entire outer resin tube 11 and the entire inner resin tube 12 have been subjected to a stretching process. By subjecting the outer resin tube 11 and the inner resin tube 12 to a stretching process, the physical properties such as tensile strength and elongation of the outer resin tube 11 and the inner resin tube 12 tend to be uniform.

The outer diameter of the outer resin tube 11 in the second region R2 is preferably smaller than the outer diameter of the outer resin tube 11 in the first region R1. In particular, the average outer diameter of the outer resin tube 11 in the second region R2 is preferably smaller than the average outer diameter of the outer resin tube 11 in the first region R1. By making the outer diameter of the outer resin tube 11 in the second region R2 smaller than the outer diameter of the outer resin tube 11 in the first region R1, the rigidity of the outer resin tube 11 in the first region R1 is increased, making it easier for force applied from the proximal side to be transmitted to the tip.

The outer diameter of the outer resin tube 11 in the first region R1 is preferably 1.05 times or more, more preferably 1.10 times or more, even more preferably 1.15 times or more, and even more preferably 1.20 times or more, of the outer diameter of the outer resin tube 11 in the second region R2. By setting the lower limit of the ratio of the outer diameters of the outer resin tube 11 in the first region R1 and the second region R2 to the above range, the outer resin tube 11 is less likely to deform in the first region R1. Therefore, the force applied from the hand side of the catheter 1 is easily transmitted to the tip of the catheter 1 through the outer resin tube 11, making it easier to improve the insertability of the catheter 1. In addition, the outer diameter of the outer resin tube 11 in the first region R1 is preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less, of the outer diameter of the outer resin tube 11 in the second region R2. By setting the upper limit of the ratio of the outer diameter of the outer resin tube 11 in the first region R1 to the second region R2 within the above range, the outer diameter of the outer resin tube 11 in the first region R1 is less likely to become excessively large, making it easier to improve the flexibility and minimal invasiveness of the catheter 1.

The length LR1 of the first region R1 in the longitudinal direction x1 is preferably longer than the length LR2 of the second region R2 in the longitudinal direction x1. By making the length LR1 of the first region R1 longer than the length LR2 of the second region R2, it becomes easier to ensure the length of the portion of the shaft 10 that is highly rigid due to the inner resin tube 12 and highly flexible due to the outer resin tube 11. As a result, the catheter 1 can be easily bent and inserted along a curved lumen in the body.

The length LR1 of the first region R1 in the longitudinal direction x1 is preferably 1.1 times or more, more preferably 1.3 times or more, even more preferably 1.5 times or more, and even more preferably 2.0 times or more, of the length LR2 of the second region R2 in the longitudinal direction x1. By setting the lower limit of the ratio of the length LR1 of the first region R1 to the length LR2 of the second region R2 within the above range, the length in the longitudinal direction x1 of the portion where the rigidity is increased by the inner resin tube 12 and the flexibility is increased by the outer resin tube 11 is likely to be sufficient, and as a result, the insertability of the catheter 1 can be improved. In addition, the length LR1 of the first region R1 in the longitudinal direction x1 is preferably 15 times or less, more preferably 10 times or less, even more preferably 8 times or less, and even more preferably 6 times or less, of the length LR2 of the second region R2 in the longitudinal direction x1. By setting the lower limit of the ratio of the length LR1 of the first region R1 to the length LR2 of the second region R2 within the above range, the proportion of the second region R2, where the outer diameter of the outer resin tube 11 is small, can be increased in the distal part of the shaft 10, improving the minimal invasiveness of the catheter 1 and improving its insertability.

The longitudinal component of the molecular orientation of the outer resin tube 11 in the second region R2 is preferably greater than the longitudinal component of the molecular orientation of the outer resin tube 11 in the first region R1. In other words, in the resin constituting the outer resin tube 11, the longitudinal component of the molecular orientation in the second region R2 is preferably greater than the longitudinal component of the molecular orientation in the first region R1. By making the longitudinal component of the molecular orientation of the outer resin tube 11 in the second region R2 greater than the longitudinal component of the molecular orientation of the outer resin tube 11 in the first region R1, the rigidity of the outer resin tube 11 can be increased in the second region R2 located distal to the first region R1. Therefore, the force applied from the proximal side of the catheter 1 is easily transmitted to the tip of the shaft 10, resulting in a catheter 1 with good insertability.

The fact that the longitudinal component of the molecular orientation of the outer resin tube 11 in the second region R2 is greater than the longitudinal component of the molecular orientation of the outer resin tube 11 in the first region R1 means that the breaking elongation of the outer resin tube 11 in the first region R1 is greater than the breaking elongation of the outer resin tube 11 in the second region R2. The breaking elongation of the outer resin tube 11 in the first region R1 is preferably 1.5 times or more than the breaking elongation of the outer resin tube 11 in the second region R2, more preferably 3.0 times or more, even more preferably 4.5 times or more, and even more preferably 6.0 times or more. By setting the lower limit of the ratio of the breaking elongation of the outer resin tube 11 in the first region R1 and the second region R2 to the above range, the rigidity of the outer resin tube 11 is increased and becomes hard, making it difficult to bend excessively. Therefore, the force applied from the hand side is easily transmitted to the tip of the shaft 10, making it easier to improve the insertability of the catheter 1. Furthermore, the breaking elongation rate of the outer resin tube 11 is unlikely to become excessively large, which makes it easier to improve the flexibility and minimal invasiveness of the catheter 1. The breaking elongation rate of the outer resin tube 11 in the first region R1 is preferably 15 times or less, more preferably 12 times or less, even more preferably 10 times or less, and even more preferably 8 times or less than the breaking elongation rate of the outer resin tube 11 in the second region R2. By setting the upper limit value of the ratio of the breaking elongation rates of the outer resin tube 11 in the first region R1 and the second region R2 to the above range, the breaking elongation rate of the outer resin tube 11 is unlikely to become excessively large, the stiffness step of the catheter 1 is reduced, the shaft 10 is easily bent in accordance with the lumen in the body, and the flexibility and minimal invasiveness of the catheter 1 are easily improved.

In the second region R2, the main orientation direction of the molecular orientation of the outer resin tube 11 and the main orientation direction of the molecular orientation of the inner resin tube 12 are preferably the longitudinal direction x1. That is, in the second region R2, the main orientation direction of the resin constituting the outer resin tube 11 is preferably the longitudinal direction x1, and the main orientation direction of the resin constituting the inner resin tube 12 is preferably the longitudinal direction x1. In the second region R2, the main orientation direction of the molecular orientation of the outer resin tube 11 and the main orientation direction of the molecular orientation of the inner resin tube 12 are preferably the longitudinal direction x1, so that the rigidity of the shaft 10 in the second region R2 can be increased. As a result, the force applied to the shaft 10 from the proximal side of the catheter 1 is easily transmitted to the tip of the shaft 10, making it easier to insert the catheter 1.

The main orientation direction of the molecules of the inner resin tube 12 is preferably the longitudinal direction x1. In other words, the most prevalent orientation direction of the entire resin constituting the inner resin tube 12 is preferably the longitudinal direction x1. By having the main orientation direction of the molecules of the inner resin tube 12 be the longitudinal direction x1, the rigidity of the entire inner resin tube 12 is increased. Therefore, the rigidity of the shaft 10 can be increased by the inner resin tube 12, and the insertability of the catheter 1 can be improved.

The main orientation direction of the molecular orientation of the outer resin tube 11 in the first region R1 may be the longitudinal direction x1 or the circumferential direction z1. By having the main orientation direction of the molecular orientation of the outer resin tube 11 in the first region R1 be the longitudinal direction x1, the rigidity of the outer resin tube 11 in the longitudinal direction x1 is increased, and the insertability of the catheter 1 can be improved. Furthermore, by having the main orientation direction of the molecular orientation of the outer resin tube 11 in the first region R1 be the circumferential direction z1, the rigidity of the outer resin tube 11 in the circumferential direction z1 can be increased, and the buckling phenomenon in which the outer resin tube 11 is crushed in the radial direction y1 while bending along the lumen in the body can be easily prevented.

In the second region R2, the longitudinal component of the molecular orientation of the outer resin tube 11 is preferably greater than the longitudinal component of the molecular orientation of the inner resin tube 12. In other words, in the second region R2, the breaking elongation of the inner resin tube 12 is preferably greater than the breaking elongation of the outer resin tube 11. In the second region R2, the longitudinal component of the molecular orientation of the outer resin tube 11 is greater than the longitudinal component of the molecular orientation of the inner resin tube 12, thereby increasing the rigidity of the shaft 10 in the second region R2. As a result, force applied to the shaft 10 from the proximal side of the catheter 1 is more easily transmitted to the tip of the shaft 10, making it easier to insert the catheter 1.

In the second region R2, the breaking elongation of the inner resin tube 12 is preferably 1.5 times or more, more preferably 2.0 times or more, and even more preferably 2.5 times or more, of the breaking elongation of the outer resin tube 11. By setting the lower limit of the ratio of the breaking elongation of the inner resin tube 12 to the breaking elongation of the outer resin tube 11 in the second region R2 to the above range, the rigidity of the shaft 10 in the second region R2 is increased and the shaft 10 becomes hard and less likely to bend excessively. As a result, the force applied from the hand side is easily transmitted to the tip of the shaft 10, making it easier to improve the insertability of the catheter 1. In addition, in the second region R2, the breaking elongation of the inner resin tube 12 is preferably 6 times or less, more preferably 5 times or less, and even more preferably 4 times or less, of the breaking elongation of the outer resin tube 11. By setting the upper limit of the ratio between the breaking elongation rate of the inner resin tube 12 and the breaking elongation rate of the outer resin tube 11 in the second region R2 within the above range, the rigidity difference of the shaft 10 in the second region R2 is reduced, making it easier for the shaft 10 to deform to fit the internal lumen of the body, and making it easier to improve the flexibility and minimal invasiveness of the catheter 1.

FIGS. 1 and 2 show a so-called rapid exchange type catheter 1, which has an opening 13 that is a guidewire port midway from the distal side to the proximal side of the shaft 10, and has a guidewire insertion passage from the opening 13 to the distal side of the shaft 10. In the case of a rapid exchange type, the outer resin tube 11 preferably has a distal tube 11a and a proximal tube 11b, and the distal tube 11a and the proximal tube 11b may be separate members. When the distal tube 11a and the proximal tube 11b are separate members, the proximal tube 11b may be made of resin or metal.

Alternatively, although not shown, the present invention can also be applied to a so-called over-the-wire type catheter 1 that has a guidewire passage from the distal side to the proximal side of the shaft 10.

In the case of a rapid exchange type catheter 1, it is preferable that the outer wall of at least one of the distal tube 11a and the proximal tube 11b is appropriately coated, and it is more preferable that the outer walls of both the distal tube 11a and the proximal tube 11b are coated. In the case of an over-the-wire type catheter 1, it is preferable that the outer wall of the outer resin tube 11 is appropriately coated.

The coating can be a hydrophilic coating or a hydrophobic coating depending on the purpose, and can be applied by immersing the shaft 10 in a hydrophilic or hydrophobic coating agent, by applying a hydrophilic or hydrophobic coating agent to the outer wall of the shaft 10, or by covering the outer wall of the shaft 10 with a hydrophilic or hydrophobic coating agent. The coating agent may contain drugs or additives.

Hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, methyl vinyl ether maleic anhydride copolymer, and hydrophilic coating agents made from any combination thereof.

Hydrophobic coating agents include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxyalkane (PFA), silicone oil, hydrophobic urethane resin, carbon coat, diamond coat, diamond-like carbon (DLC) coat, ceramic coat, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

The outer resin tube 11 has an opening 13 in the peripheral wall thereof that connects the outside of the outer resin tube 11 to the inner cavity of the inner resin tube 12, and the opening 13 is preferably located proximal to the distal end 20d of the core material 20. By locating the opening 13 proximal to the distal end 20d of the core material 20, the core material 20 can increase the rigidity near the opening 13. Therefore, when sending an article or fluid through the opening 13 into the inner cavity of the inner resin tube 12, it is easy to insert the article or fluid into the opening 13. The inner resin tube 12 is a guidewire tube for inserting a guidewire, and the opening 13 is preferably a guidewire port that serves as an insertion port for the guidewire.

The catheter 1 preferably has a treatment section disposed at the distal portion of the outer resin tube 11. The treatment section performs treatment on a target site such as a lesion in a lumen within the body. Examples of the treatment section include an expansion member 30 such as a balloon, stent, or basket, electrodes for measuring intracardiac potentials or passing high-frequency current, and a drug holding section for releasing drugs.

The catheter 1 preferably further has a balloon 31 disposed in the distal portion of the outer resin tube 11. In other words, the catheter 1 is preferably a balloon catheter having a balloon 31 that is an expansion member 30.

The balloon 31 preferably has a straight tube section 34, a proximal taper section 33 located proximal to the straight tube section 34, and a distal taper section 35 located distal to the straight tube section 34. The balloon 31 may further have a proximal sleeve section 32 located proximal to the proximal taper section 33, and a distal sleeve section 36 located distal to the distal taper section 35.

The balloon 31 is preferably made of a resin, and more preferably made of a thermoplastic resin. By making the balloon 31 of a resin, it becomes easier to manufacture the balloon 31 by molding.

The resin constituting the balloon 31 may be, for example, a polyolefin resin such as polyethylene, polypropylene, or ethylene-propylene copolymer; a polyester resin such as polyethylene terephthalate or polyester elastomer; a polyurethane resin such as polyurethane or polyurethane elastomer; a polyamide resin such as polyphenylene sulfide resin, polyamide or polyamide elastomer; a fluorine-based resin, a silicone resin, or a natural rubber such as latex rubber. These may be used alone or in combination of two or more. Among them, polyamide resin, polyester resin, or polyurethane resin is preferably used as the resin constituting the balloon 31. In particular, from the viewpoint of thinning and flexibility of the balloon 31, it is preferable to use an elastomer resin as the resin constituting the balloon 31. For example, among polyamide resins, nylon 12, nylon 11, etc. are suitable materials for constituting the balloon 31, and nylon 12 is preferably used because it is relatively easy to mold during blow molding. In addition, from the viewpoint of thinning and flexibility of the balloon 31, a polyamide elastomer such as polyether ester amide elastomer or polyamide ether elastomer is preferably used as the resin constituting the balloon 31. Among these, polyether ester amide elastomer is preferably used as the resin that constitutes the balloon 31 because it has high yield strength and good dimensional stability of the balloon 31.

When the catheter 1 has a balloon 31, the catheter 1 is configured so that fluid is supplied to the inner cavity of the balloon 31 through the shaft 10, and the expansion and contraction of the balloon 31 can be controlled using an indeflator (a balloon pressurizer/depressurizer). The fluid may be a pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied to the inner cavity of the balloon 31 may be referred to as the "balloon expansion fluid."

If the catheter 1 is an over-the-wire type balloon catheter, it is preferable that the inflation lumen and the guidewire lumen extend to the hub 5 located on the proximal side, and that the proximal opening of each lumen is provided in the bifurcated hub 5.

When the catheter 1 has a balloon 31, it is preferable that a tip member (not shown) is provided at the distal end of the catheter 1. The tip member may be provided at the distal end of the balloon catheter by being connected to the distal end of the balloon 31 as a separate member from the inner resin tube 12, or the distal end of the inner resin tube 12 may function as the tip member by extending the inner resin tube 12 further distal than the distal end of the balloon 31.

Inside the balloon 31, at the portion where the balloon 31 is located in the longitudinal direction x1 on the inner resin tube 12, a radiopaque marker 40 may be placed so that the position of the balloon 31 can be confirmed under X-ray fluoroscopy. The location where the radiopaque marker 40 is placed may be, for example, a position corresponding to both ends of the straight tube section 34 of the balloon 31 or a position corresponding to the center of the straight tube section 34 of the balloon 31. In particular, it is preferable that the radiopaque marker 40 is placed at a position corresponding to both ends of the straight tube section 34 of the balloon 31.

The shape of the radiopaque marker 40 is preferably tubular, and examples of such shapes include a cylindrical shape, a polygonal cylindrical shape, a shape with a C-shaped cross section with a notch in the tube, and a coil shape with wound wire. The material constituting the radiopaque marker 40 can be, for example, an radiopaque substance such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, or a cobalt chromium alloy.

A position marker 60 may be provided on the shaft 10 to confirm the length to which the catheter 1 has been inserted into the body cavity. Methods for providing the position marker 60 on the shaft 10 include, for example, placing a marker member on the outer resin tube 11 or the inner resin tube 12, partially coloring the outer surface of the outer resin tube 11 or the inner resin tube 12, or partially peeling off the coating applied to the outer surface of the outer resin tube 11 or the inner resin tube 12. The number of position markers 60 provided on the shaft 10 may be one or more.

FIG. 7 is a modified example of FIG. 3, and is a cross-sectional view perpendicular to the longitudinal direction x1 on the distal side of the opening 13 of the catheter 1. FIG. 8 is a modified example of FIG. 4, and is a cross-sectional view perpendicular to the longitudinal direction x1 on the proximal side of the opening 13 of the catheter 1.

As shown in Figures 2 to 4, the shaft 10 has a gap between the outer surface of the inner resin tube 12 and the inner surface of the outer resin tube 11, and balloon expansion fluid may be supplied to the inner cavity of the balloon 31 through the space between the outer surface of the inner resin tube 12 and the inner surface of the outer resin tube 11. However, as shown in Figures 7 and 8, it is preferable that the shaft 10 has a fluid supply tube 14 that is connected to the inner cavity of the balloon 31 and through which balloon expansion fluid is supplied.

As shown in Figures 7 and 8, the shaft 10 has a fluid supply tube 14 that is in communication with the inner cavity of the balloon 31 and through which fluid is supplied, and the fluid supply tube 14 is preferably disposed within the inner cavity of the outer resin tube 11 and outside the inner resin tube 12. By having the fluid supply tube 14, the shaft 10 is less likely to be damaged when balloon expansion fluid is pumped into the inner cavity of the balloon 31, and the durability of the catheter 1 can be increased.

When the shaft 10 has a fluid supply tube 14, it is preferable that there is no gap between the outer surface of the inner resin tube 12 and the outer surface of the fluid supply tube 14 and the inner surface of the outer resin tube 11. In other words, it is preferable that there is no gap between the outer surface of the inner resin tube 12 and the inner surface of the outer resin tube 11, and that there is no gap between the outer surface of the fluid supply tube 14 and the inner surface of the outer resin tube 11. By having no gap between the outer surface of the inner resin tube 12 and the outer surface of the fluid supply tube 14 and the inner surface of the outer resin tube 11, the rigidity of the shaft 10 is increased, making it easier to improve the insertability of the shaft 10.

In order to configure the shaft 10 so that there are no gaps between the outer surface of the inner resin tube 12 and the outer surface of the fluid supply tube 14 and the inner surface of the outer resin tube 11, for example, the outer resin tube 11 may be welded to the inner cavity of the outer resin tube 11 while the inner resin tube 12 and the fluid supply tube 14 are placed in the inner cavity of the outer resin tube 11, or the inner surface of the outer resin tube 11 may be formed by placing the inner resin tube 12 and the fluid supply tube 14 in the inner cavity of the outer resin tube 11 and pouring an adhesive into the gap between the outer surface of the inner resin tube 12 and the outer surface of the fluid supply tube 14 and the inner surface of the outer resin tube 11.

As shown in Figures 7 and 8, the cross-sectional shape of the lumen of the fluid supply tube 14 in a cross section perpendicular to the longitudinal direction x1 is preferably elliptical. By making the cross-sectional shape of the lumen of the fluid supply tube 14 elliptical, the cross-sectional area of the lumen of the fluid supply tube 14 in the lumen of the outer resin tube 11 is increased, while also making it easier to ensure the thickness of the shaft 10 near the fluid supply tube 14. As a result, the pressure resistance of the shaft 10 can be improved, allowing more fluid to be sent to the balloon 31, and the balloon 31 can be expanded and contracted quickly, shortening the procedure time.

When the cross-sectional shape of the lumen of the fluid supply tube 14 in a cross section perpendicular to the longitudinal direction x1 is elliptical, the length of the major axis in the cross-sectional shape of the lumen of the fluid supply tube 14 is preferably 1.2 times or more, more preferably 1.5 times or more, and even more preferably 2.0 times or more, of the minor axis in the cross-sectional shape of the lumen of the fluid supply tube 14. By setting the lower limit of the ratio of the major axis length to the minor axis length in the cross-sectional shape of the lumen of the fluid supply tube 14 to the above range, it becomes easier to ensure the thickness of the shaft 10 while ensuring the size of the lumen of the fluid supply tube 14. In addition, the length of the major axis in the cross-sectional shape of the lumen of the fluid supply tube 14 is preferably 7 times or less, more preferably 5 times or less, and even more preferably 3 times or less, of the minor axis in the cross-sectional shape of the lumen of the fluid supply tube 14. By setting the upper limit of the ratio of the long axis length to the short axis length in the cross-sectional shape of the lumen of the fluid supply tube 14 within the above range, it is possible to easily increase the cross-sectional area of the lumen of the fluid supply tube 14 without excessively increasing the outer diameter of the outer resin tube 11.

This application claims the benefit of priority based on Japanese Patent Application No. 2023-142514, filed on September 1, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-142514, filed on September 1, 2023, are incorporated by reference into this application.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples, and may be modified within the scope of the above and below mentioned aims, and all such modifications are within the technical scope of the present invention.

(Measurement of molecular orientation)
Three test pieces, each 50 mm long, were cut out from the outer resin tube and the inner resin tube. Both ends of each test piece were fixed with a chuck using a universal testing machine (Strograph E3-L, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the test piece was pulled with a chuck distance of 25 mm and a tensile speed of 500 mm/min. The chuck distance at break was measured, and the breaking elongation was calculated using the following formula.
Breaking elongation = (chuck distance at break - chuck distance at start of tension) / chuck distance at start of tension

(Penetrability evaluation)
Fig. 9 is a schematic diagram of an evaluation circuit used to evaluate the insertability of a catheter. The insertability was evaluated by measuring the pushing load applied to the proximal side of the catheter when the second region of the catheter passes through a branching part with an angle of about 135 degrees of an evaluation circuit formed with a cylindrical circuit with an inner diameter of about 4 mm as shown in Fig. 9 in warm water at about 37°C. In Fig. 9, the direction of insertion of the catheter into the evaluation circuit is indicated by a dashed arrow, and the force for pushing the catheter is indicated by a hollow arrow.

[Example 1]
An outer resin tube was produced by extrusion molding using a polyamide elastomer and then stretching, the first region having an outer diameter of 1.3 mm and an inner diameter of 1.0 mm, and the second region having an outer diameter of 1.1 mm and an inner diameter of 1.0 mm. An inner resin tube was produced by extrusion molding using a polyamide elastomer for the outer layer and a polyethylene for the inner layer and then stretching, the inner resin tube having an outer diameter of 0.7 mm and an inner diameter of 0.5 mm.

A catheter was fabricated using the obtained outer resin tube and inner resin tube, and an evaluation of the insertability was performed. In addition, the molecular orientation of the obtained outer resin tube and inner resin tube in the first and second regions was measured. The results are shown in Table 1.

[Example 2]
The outer resin tube was stretched to produce an outer resin tube with an outer diameter of 1.3 mm and an inner diameter of 1.1 mm in the first and second regions, and the outer and inner resin tubes were produced in the same manner as in Example 1. The outer and inner resin tubes were used to produce catheters, and the insertability was evaluated. The molecular orientations in the first and second regions were measured. The results are shown in Table 1.

[Example 3]
The outer resin tube was stretched to produce an outer resin tube with an outer diameter of 1.5 mm and an inner diameter of 1.3 mm in the first and second regions, and the inner resin tube was stretched to produce an inner resin tube with an outer diameter of 1.0 mm and an inner diameter of 0.6 mm in the first and second regions. The outer resin tube and the inner resin tube were produced in the same manner as in Example 1, except that the outer resin tube and the inner resin tube were stretched to produce a catheter with an outer diameter of 1.0 mm and an inner diameter of 0.6 mm in the first and second regions. The catheter was produced using the obtained outer resin tube and the inner resin tube, and the insertability was evaluated. In addition, the molecular orientation in each of the first and second regions was measured. The results are shown in Table 1.

[Example 4]
The outer resin tube was stretched to produce an outer resin tube with an outer diameter of 1.3 mm and an inner diameter of 1.0 mm in the first and second regions, and the outer and inner resin tubes were produced in the same manner as in Example 1. The outer and inner resin tubes were used to produce catheters, and the insertability was evaluated. The molecular orientations in the first and second regions were measured. The results are shown in Table 1.

[Comparative Example 1]
An outer resin tube having an outer diameter of 1.3 mm and an inner diameter of 1.0 mm was produced by extrusion molding using a polyamide elastomer. An inner resin tube having an outer diameter of 0.6 mm and an inner diameter of 0.5 mm was produced by extrusion molding using a polyamide elastomer for the outer layer and a polyethylene for the inner layer. The outer resin tube and the inner resin tube were not subjected to stretching.

A catheter was fabricated using the obtained outer resin tube and inner resin tube, and an evaluation of the insertability was performed. In addition, the molecular orientation of the obtained outer resin tube and inner resin tube in the first and second regions was measured. The results are shown in Table 1.

As shown in Table 1, in the catheters of Examples 1 to 4, the longitudinal component of the molecular orientation of the inner resin tube in the first region was greater than the longitudinal component of the molecular orientation of the outer resin tube. It was confirmed that the pushing load applied to the proximal side of the catheter when passing through the branching portion of the evaluation circuit was smaller in Examples 2 to 4 than in Comparative Example 1, and the pushing load in Example 1 was even smaller. In other words, compared to Comparative Example 1, the catheters of Examples 1 to 4 had superior catheter insertability performance.

1: Catheter 5: Hub 6: Fluid injection section 10: Shaft 10d: Distal end of shaft 10p: Proximal end of shaft 11: Outer resin tube 11d: Distal end of outer resin tube 11p: Proximal end of outer resin tube 11a: Distal tube 11b: Proximal tube 12: Inner resin tube 12d: Distal end of inner resin tube 12p: Proximal end of inner resin tube 13: Opening 14: Fluid supply tube 20: Core material 20d: Distal end of core material 20p: Proximal end of core material 30: Expansion member 31: Balloon 32: Proximal sleeve portion 33: Proximal tapered portion 34: Straight tube portion 35: Distal tapered portion 36: Distal sleeve portion 40: X-ray opaque marker 60: Position marker R1: First region R2: Second region L1: Distance between chucks when tension begins L2: Distance between chucks at break LR1: Length of first region LR2: Length of second region

Claims (9)

A shaft having a longitudinal direction and a circumferential direction along an outer periphery in a cross section perpendicular to the longitudinal direction, the shaft having an inner cavity extending in the longitudinal direction;
a core disposed in the lumen of the shaft;
The shaft includes an outer resin tube and an inner resin tube disposed in an inner cavity of the outer resin tube,
The shaft has a first region located distal to a distal end of the core material and a second region located distal to the first region,
A catheter, wherein in the first region, the longitudinal component of the molecular orientation of the inner resin tube is greater than the longitudinal component of the molecular orientation of the outer resin tube. The catheter of claim 1, wherein the outer diameter of the outer resin tube in the second region is smaller than the outer diameter of the outer resin tube in the first region. The catheter according to claim 1, wherein the longitudinal component of the molecular orientation of the outer resin tube in the second region is greater than the longitudinal component of the molecular orientation of the outer resin tube in the first region. The catheter according to claim 1, wherein in the second region, the main orientation direction of the molecular orientation of the outer resin tube and the main orientation direction of the molecular orientation of the inner resin tube are the longitudinal direction. The catheter according to claim 1, wherein the main molecular orientation direction of the inner resin tube is the longitudinal direction. The catheter according to claim 1, wherein in the second region, the longitudinal component of the molecular orientation of the outer resin tube is greater than the longitudinal component of the molecular orientation of the inner resin tube. an opening is provided in a peripheral wall of the outer resin tube, the opening communicating an outside of the outer resin tube with an inner cavity of the inner resin tube;
The catheter of claim 1 , wherein the opening is located proximal to a distal end of the core material. The catheter of claim 1 further comprising a balloon disposed in the distal portion of the outer resin tube. The shaft has a fluid supply tube that is in communication with an inner cavity of the balloon and through which a fluid is supplied;
the fluid supply tube is disposed inside the outer resin tube and outside the inner resin tube,
The catheter according to claim 8 , wherein a cross-sectional shape of the lumen of the fluid supply tube in a cross section perpendicular to the longitudinal direction is an ellipse.

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