JP2022121902A - catheter - Google Patents

Abstract

To provide a catheter in which a flow of a fluid body supplied to the inside of a balloon is easily controlled.SOLUTION: A catheter 1 includes a shaft 2 having a distal end and a proximal end in a longitudinal axis direction x and a balloon 30 arranged in a distal part of the shaft 2. The shaft 2 has an outer shaft 10 having a lumen extending in the longitudinal axis direction x and an inner shaft 20 arranged in the lumen of the outer shaft 10. The outer shaft 10 has a first section 11 in which an inner diameter is smaller than an inner diameter in a central position in the longitudinal axis direction x of the outer shaft 10 in the distal part. The inner shaft 20 has a first cylinder 21 and a second cylinder 22 positioned on a proximal side with respect to the first cylinder 21. The first cylinder 21 and the second cylinder 22 are connected to each other at a connecting part 23, and the connecting part 23 is positioned in the first section 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to catheters, particularly balloon catheters.

BACKGROUND ART Various diseases are known to occur when blood vessels, which are flow paths for blood circulation in the body, become stenotic and the blood circulation is stagnant. In particular, stenosis of coronary arteries that supply blood to the heart may lead to serious diseases such as angina pectoris and myocardial infarction. One of the methods for treating such stenosis of blood vessels is angioplasty (PTA, PTCA, etc.) in which a balloon catheter is used to dilate the stenosis. Angioplasty is widely performed because it is a minimally invasive therapy that does not require a thoracotomy like bypass surgery. Patent Literature 1 discloses an example of a balloon catheter.

U.S. Patent Application Publication No. 2009/156998

By the way, providing a catheter that can efficiently control the flow of fluid for expanding a balloon is beneficial from the viewpoint of diversification of procedures. Accordingly, an object of the present invention is to provide a catheter that facilitates control of the flow of fluid supplied to the inside of the balloon.

One embodiment of the catheter of the present invention that can achieve the above objects comprises a shaft having a distal end and a proximal end in the longitudinal direction, and a balloon disposed on the distal portion of the shaft, the shaft has an outer shaft having a longitudinally extending lumen, an inner shaft disposed in the lumen of the outer shaft, the outer shaft extending at its distal portion along the length of the outer shaft. The inner shaft has a first section with an inner diameter smaller than the inner diameter at the central position in the axial direction, the inner shaft has a first tube, and a second tube located closer to the proximal side than the first tube. The gist is that the first tube and the second tube are connected to each other at the connecting portion, and the connecting portion is located in the first section. According to the catheter described above, since the connecting portion between the first and second tubes of the inner shaft is located in the first section of the outer shaft, the portion of the first section where the connecting section is disposed is the outer shaft. and the inner shaft. Since it is possible to reduce the flow velocity in the portion where the connecting portion is arranged, it becomes easier to control the flow of the fluid supplied to the inside of the balloon using the connecting portion.

The connection may be located proximally of the first section or may be located distally of the first section. A second tube may be inserted into the lumen of the first tube at the connecting portion.

The inner diameter of the outer shaft may be constant in the first section. The outer shaft may have a reduced diameter portion in which the inner diameter of the outer shaft decreases toward the distal end side in the first section.

The outer shaft has a second section arranged proximally adjacent to the first section and having a larger inner diameter than the first section, and the outer shaft has a step at the boundary between the first section and the second section. may be

The inner shaft may extend from the distal end of the outer shaft, the distal end of the balloon being fixed to the inner shaft and the proximal end of the balloon being fixed to the first section of the outer shaft.

The length of the first section in the longitudinal direction may be longer than the length of the balloon. The expanded outer diameter of the balloon may be less than the maximum outer diameter of the shaft.

The outer shaft has a second section arranged proximally adjacent to the first section and having an inner diameter larger than that of the first section. It may be smaller than the maximum outer diameter.

The outer shaft has a second section arranged proximally adjacent to the first section and having a larger inner diameter than the first section, and the maximum outer diameter of the inner shaft is the maximum of the outer shaft in the first section. It may be 80% or more of the inner diameter, and the maximum outer diameter of the inner shaft in the second section may be 70% or less of the maximum inner diameter of the outer shaft in the second section.

According to the catheter described above, since the connecting portion between the first and second tubes of the inner shaft is located in the first section of the outer shaft, the portion of the first section where the connecting section is disposed is the outer shaft. and the inner shaft. Since it is possible to reduce the flow velocity in the portion where the connecting portion is arranged, it becomes easier to control the flow of the fluid supplied to the inside of the balloon using the connecting portion.

1 is a side view of a catheter according to one embodiment of the invention; FIG. 2 is an enlarged cross-sectional view of the distal side of the catheter shown in FIG. 1; FIG. FIG. 3 is a cross-sectional view showing a modification of the catheter shown in FIG. 2; 3 is a cross-sectional view showing another modification of the catheter shown in FIG. 2; FIG. 3 is a cross-sectional view showing still another modification of the catheter shown in FIG. 2; FIG. FIG. 2 is a side view showing a modification of the catheter shown in FIG. 1; 3 is a cross-sectional view showing still another modification of the catheter shown in FIG. 2; FIG.

Hereinafter, the present invention will be described in more detail based on the following embodiments, but the present invention is not limited by the following embodiments, and can be modified appropriately within the scope of the above and later descriptions. It is of course possible to carry out in addition, and all of them are included in the technical scope of the present invention. In each drawing, for the sake of convenience, hatching, member numbers, etc. may be omitted. In such cases, the specification and other drawings shall be referred to. In addition, the dimensions of various members in the drawings may differ from the actual dimensions, since priority is given to helping to understand the features of the present invention.

One embodiment of the catheter of the present invention comprises a shaft having longitudinally distal and proximal ends, and a balloon disposed on the distal portion of the shaft, the shaft extending longitudinally. and an inner shaft disposed in the lumen of the outer shaft, the outer shaft distally extending at a longitudinally central location of the outer shaft. The inner shaft has a first section with an inner diameter smaller than the inner diameter, and the inner shaft has a first tube and a second tube positioned closer to the proximal side than the first tube. The gist is that they are connected to each other at the connecting portion, and the connecting portion is located in the first section. According to the catheter described above, since the connecting portion between the first and second tubes of the inner shaft is located in the first section of the outer shaft, the portion of the first section where the connecting section is disposed is the outer shaft. and the inner shaft. Since it is possible to reduce the flow velocity in the portion where the connecting portion is arranged, it becomes easier to control the flow of the fluid supplied to the inside of the balloon using the connecting portion.

The configuration of the catheter will be described with reference to FIGS. 1 to 7. FIG. 1 is a side view of a catheter according to one embodiment of the invention; FIG. FIG. 2 is an enlarged cross-sectional view of the distal side of the catheter shown in FIG. 3 to 5 and 7 are sectional views showing modifications of the catheter shown in FIG. 6 is a side view showing a modification of the catheter shown in FIG. 1. FIG. FIG. 1 shows a configuration example of a rapid exchange balloon catheter through which a guide wire can be inserted from the distal side to the proximal side of the shaft. The configuration of the catheter 1 can also be applied to an over-the-wire balloon catheter through which a guidewire can be passed from the distal side to the proximal side of the shaft 2 . The catheter 1 comprises a shaft 2 and a balloon 30 arranged at the distal portion of the shaft 2, the shaft 2 having an outer shaft 10 having a lumen 10c extending in the longitudinal direction x; and an inner shaft 20 arranged in the lumen 10 c of the outer shaft 10 .

The distal side of the catheter 1 refers to the treatment target side on the distal end 10a side of the shaft 2 in the longitudinal direction x. The proximal side of the device refers to the proximal end side of the shaft 2 in the longitudinal direction x and the user's hand side. When each member is divided into two halves along its longitudinal axis, the proximal side may be called the proximal portion, and the distal side may be called the distal portion.

The shaft 2 is an elongate member having a longitudinal axis direction x. The shaft 2 has a distal end 10a and a proximal end in the longitudinal direction x. The shaft 2 has therein a fluid flow path and a guide wire passage for guiding the movement of the shaft 2 . A space between the outer shaft 10 and the inner shaft 20 functions as a fluid flow path. A space between the outer shaft 10 and the inner shaft 20 is located inside the lumen 10 c of the outer shaft 10 . A lumen 20c of the inner shaft 20 functions as an insertion passage for the guide wire. Catheter 1 may include a guidewire extending in longitudinal direction x of shaft 2 .

A distal end 30 a and a proximal end 30 b of balloon 30 are each joined to shaft 2 . In FIG. 2, the inner shaft 20 extends from the distal end 10a of the outer shaft 10, the distal end 30a of the balloon 30 is fixed to the outer surface of the inner shaft 20, and the proximal end 30b of the balloon 30 is the outer surface. It is fixed to the outer surface of the shaft 10 .

A hub 40 is arranged at the proximal portion of the shaft 2 . The catheter 1 is configured such that fluid is supplied to the inside of the balloon 30 from the hub 40 through the shaft 2 . Supplying fluid to the interior of balloon 30 causes balloon 30 to expand. Removing fluid from the interior of balloon 30 causes balloon 30 to deflate.

The hub 40 may have a fluid injection portion in communication with the fluid flow path. If catheter 1 is an over-the-wire balloon catheter, hub 40 may have a guidewire port. In the case of a rapid exchange balloon catheter as shown in FIG. 1, the guide wire port 41 is arranged in the middle of the shaft 2. The hub 40 may have at least one of an injection port for drugs and the like and a suction port for fluids in the living body cavity.

The shaft 2, the balloon 30, and the hub 40 can be joined using a method such as bonding with an adhesive or heat welding.

The balloon 30 can be manufactured by molding resin. Examples of the resin forming the balloon 30 include polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, polyphenylene sulfide-based resins, fluorine-based resins, vinyl chloride-based resins, silicone-based resins, and natural rubber. These may use only 1 type and may use 2 or more types together.

The balloon 30 may be provided with stiffeners in order to improve its dilatability against hardened stenosed lesions and its dimensional stability against dilatation pressure. As the reinforcing material, for example, a fiber material can be used, and specifically, polyarylate fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, PBO fiber, carbon fiber, etc. are preferably used. These fibrous materials may be monofilaments or multifilaments.

The balloon 30 may be of a so-called non-compliant type in which the outer diameter of the balloon 30 hardly increases even if the expansion pressure is increased above a predetermined expansion pressure, or a so-called compliant type in which the outer diameter changes according to the expansion pressure. It may be client type.

A typical balloon shape is a truncated cone at the proximal and distal tapers and a straight tube between the proximal and distal tapers, as shown in FIG. Although the portion is often cylindrical, it is not limited to this shape. For example, the straight tube portion may be slightly inclined depending on the shape of the lesion, as long as the angle of inclination is smaller than that of the proximal and distal tapers.

The outer shaft 10 has, at its distal portion, a first section 11 whose inner diameter is smaller than the inner diameter at the central position of the outer shaft 10 in the longitudinal direction x. The inner shaft 20 has a first tube 21 and a second tube 22 positioned closer to the proximal side than the first tube 21 , and the first tube 21 and the second tube 22 are connected to each other at a connecting portion 23 . , and the connecting portion 23 is located in the first section 11 . According to the catheter 1, since the connection portion 23 of the inner shaft 20 is located in the first section 11 of the outer shaft 10, the portion where the connection portion 23 is arranged is located between the outer shaft 10 and the inner shaft 20. The cross-sectional area of the space can be reduced. Since it is possible to reduce the flow velocity in the portion where the connecting portion 23 is arranged, it becomes easier to control the flow of the fluid supplied to the inside of the balloon 30 using the connecting portion 23 . In addition, since the gap between the outer shaft 10 and the inner shaft 20 is small at the portion where the connecting portion 23 is arranged, the inner shaft 20 is less likely to bend in the first section 11 when the catheter 1 is passed through the lesion. . As a result, the user's pushing force on the catheter 1 can be easily transmitted to the distal end of the catheter 1 . The central position of the outer shaft 10 in the longitudinal direction x is the central position in the longitudinal direction x of the exposed portion of the outer shaft 10 in the catheter 1 .

As the outer shaft 10 or the inner shaft 20, a hollow body formed by arranging one or more wires in a predetermined pattern; at least one of the inner surface or the outer surface of the hollow body is coated with a resin; tubes; or combinations thereof, such as those connected longitudinally. A hollow body in which wires are arranged in a predetermined pattern includes a tubular body having a mesh structure formed by simply crossing or weaving wires, and a coil in which wires are wound. The wire may be one or more solid wires or one or more twisted wires. A resin tube can be manufactured, for example, by extrusion molding. The resin tube can consist of a single layer or multiple layers. A part of the resin tube in the longitudinal axis direction or the circumferential direction may be composed of a single layer, and the other part may be composed of multiple layers. Both the outer shaft 10 and the inner shaft 20 are preferably resin tubes.

The outer shaft 10 or the inner shaft 20 is made of, for example, polyolefin resin (eg, polyethylene or polypropylene), polyamide resin (eg, nylon), polyester resin (eg, PET), aromatic polyether ketone resin (eg, PEEK), poly It can be made of synthetic resin such as ether polyamide resin, polyurethane resin, polyimide resin, fluorine resin (for example, PTFE, PFA, ETFE), or metal such as stainless steel, carbon steel, nickel-titanium alloy. These may be used individually by 1 type, and may be used in combination of 2 or more types.

The first section 11 extends in the longitudinal direction x. The distal end 11a of the first section 11 preferably coincides with the distal end 10a of the outer shaft 10, but may be located proximal to the distal end 10a.

As shown in FIG. 2, the inner shaft 20 extends from the distal end 10a of the outer shaft 10, the distal end 30a of the balloon 30 is fixed to the inner shaft 20, and the proximal end 30b of the balloon 30 is It is preferably fixed to the first section 11 of the outer shaft 10 . By fixing the proximal end portion 30b of the balloon 30 to the first section 11, the outer diameter of the balloon 30 during expansion can be appropriately set.

Preferably, the length of the first section 11 is longer than the length of the balloon 30 in the longitudinal direction x, as shown in FIG. This configuration makes it easier to control the flow of fluid in the first section 11 . The length of the first section 11 in the longitudinal direction x may be 1.2 times or more, 1.5 times or more, 2 times or more, 7 times or less, and 6.5 times or less the length of the balloon 30. , 6 times or less.

As shown in FIG. 1, the expanded outer diameter of the balloon 30 is preferably smaller than the maximum outer diameter of the shaft 2 . By setting the outer diameters of the balloon 30 and the shaft 2 in this manner, the catheter 1 can be easily used in a very narrow body cavity. The outer diameter of the balloon 30 when inflated is preferably larger than the maximum outer diameter of the first section 11 of the outer shaft 10 . Further, the outer diameter of the balloon 30 when folded may be larger than the maximum outer diameter of the first section 11 of the outer shaft 10 .

The outer diameter of the balloon 30 when expanded may be 1.1 times or more, 1.15 times or more, 1.2 times or more, 2 times or less, or 1.7 times the outer diameter of the balloon 30 when folded. Below, it may be 1.5 times or less.

The thickness of the outer shaft 10 may be constant in the first section 11 . Further, when the outer diameter of the first section 11 is constant, the thickness of the outer shaft 10 in the first section 11 may decrease or increase toward the distal end 10a of the outer shaft 10 . By changing the size of the cross-sectional area of the space of the first section 11, the flow velocity of the fluid supplied to the balloon 30 can be controlled.

As shown in FIG. 2 , the inner diameter of the outer shaft 10 may be constant in the first section 11 . With this configuration, the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 at the connecting portion 23 can be controlled by changing the shape or outer diameter of the connecting portion 23 . For the same reason, the outer diameter of the outer shaft 10 may be constant in the first section 11 . Here, the expression that the inner diameter or the outer diameter of the outer shaft 10 is constant includes a mode in which the inner diameter or the outer diameter fluctuates within a range of ±5%. The same applies to the following description.

As shown in FIG. 3 , the outer shaft 10 may have a reduced-diameter portion 14 in the first section 11 in which the inner diameter of the outer shaft 10 decreases toward the distal end 10a. Due to the presence of the reduced diameter portion 14 , the size of the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 at the connection portion 23 can be easily changed in the longitudinal axis direction x.

The reduced diameter portion 14 may be arranged only in a part of the first section 11 or may be arranged over the entire first section 11 .

At the reduced diameter portion 14 , the inner diameter of the outer shaft 10 may be tapered toward the distal end 10 a of the outer shaft 10 . Also, at the reduced diameter portion 14 , the inner diameter of the outer shaft 10 may be gradually reduced toward the distal end 10 a side of the outer shaft 10 .

At the reduced diameter portion 14 , the outer diameter of the outer shaft 10 may be tapered toward the distal end 10 a of the outer shaft 10 . In the reduced diameter portion 14 , the outer diameter of the outer shaft 10 may be gradually reduced toward the distal end 10 a of the outer shaft 10 . At the reduced diameter portion 14, the thickness of the outer shaft 10 may be constant or may vary.

The inner shaft 20 is formed by connecting a first tube 21 and a second tube 22 in the longitudinal direction x. At least part of the second tube 22 needs to be positioned closer to the proximal side than the first tube 21, and the entire second tube 22 need not be positioned closer to the first tube 21. .

It is preferable that each of the first tube 21 and the second tube 22 is a resin tube. The resin tube can consist of a single layer or multiple layers. Each resin tube may be composed of a single layer in one part in the longitudinal direction or in the circumferential direction, and may be composed of a plurality of layers in the other part.

The method of connecting the first tube 21 and the second tube 22 at the connecting portion 23 is not particularly limited. ), the first barrel 21, the proximal end and the distal end of the second barrel 22 are glued or welded, and the first barrel 21, the proximal end and the distal end of the second barrel 22 are tightened. The rings can be crimped together or connected by a combination of these methods. The clamping ring may be a radiopaque marker.

As shown in FIG. 2 , it is preferable that the second tube 22 is inserted into the lumen 21 c of the first tube 21 at the connecting portion 23 . Specifically, it is preferable that the distal end portion of the second tube 22 is inserted into the lumen 21 c at the proximal end portion of the first tube 21 . This configuration makes it easier for the guidewire to pass through the connecting portion 23 when the guidewire inserted into the lumen 20c of the inner shaft 20 is fed distally.

The first tube 21 may be inserted into the lumen 22 c of the second tube 22 at the connecting portion 23 . Also, the connecting portion 23 may be formed by a tube other than the first tube 21 and the second tube 22 that covers the proximal end of the first tube 21 and the distal end of the second tube 22 . In this case, the proximal end of the first tube 21 and the distal end of the second tube 22 may abut or be separated from each other. It is preferable that the first tube 21 and the second tube 22 are in close contact with each other at the connecting portion 23 .

In a mode where there is a section where the first tube 21 and the second tube 22 overlap in the longitudinal axis direction x, the overlapping section is regarded as the connecting portion 23 . For example, a mode in which either one of the first tube 21 and the second tube 22 is inserted into the lumen of the other corresponds. A mode in which there is no section where the first tube 21 and the second tube 22 overlap in the longitudinal direction x, for example, the first tube 21 and the second tube 22 are butt-joined, and a tightening ring is attached to the first tube from the outside of the joint. 21 and the second cylinder 22 are crimped, the section where the tightening ring is arranged is regarded as the connecting portion 23 . As shown in FIG. 2 , the first tube 21 and the second tube 22 have non-connecting portions 21 a and 22 a other than the connecting portion 23 in the first section 11 . The first tube 21 has a non-connecting portion 21 a distally of the connecting portion 23 , and the second tube 22 has a non-connecting portion 22 a proximally of the connecting portion 23 .

The inner shaft 20 is fixed to the outer shaft 10 so as not to be displaced in the longitudinal direction x. For this reason, the connecting portion 23 is also arranged so that the position of the longitudinal axis direction x with respect to the outer shaft 10 is not deviated.

The maximum outer diameter of the connecting portion 23 is preferably larger than the maximum outer diameter of the non-connecting portion 21 a of the first cylinder 21 . Also, the maximum outer diameter of the connecting portion 23 is preferably larger than the maximum outer diameter of the non-connecting portion 22 a of the second cylinder 22 . At the connecting portion 23, the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be easily reduced.

The maximum outer diameter of the connecting portion 23 may be 1.1 times or more, 1.2 times or more, or 1.3 times or more the maximum outer diameter of the non-connecting portion 21 a of the first cylinder 21 . The size may be 1.5 times or less, 1.7 times or less, or 1.5 times or less. The maximum outer diameter of the connecting portion 23 may be 1.02 times or more, 1.05 times or more, or 1.07 times or more the maximum outer diameter of the non-connecting portion 22a of the second cylinder 22. .7 times or less, 1.5 times or less, or 1.3 times or less.

The maximum outer diameter of the non-connecting portion 22 a of the second tube 22 is preferably larger than the maximum outer diameter of the non-connecting portion 21 a of the first tube 21 . The cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be reduced from the proximal side to the distal side of the first section 11, making it easier to control the flow of fluid in the entire first section 11. .

The maximum outer diameter of the non-connecting portion 22a of the second tube 22 is 1.05 times or more, 1.08 times or more, or 1.1 times or more the maximum outer diameter of the non-connecting portion 21a of the first tube 21. It may be 1.5 times or less, 1.4 times or less, or 1.3 times or less.

The length of the connecting portion 23 in the longitudinal direction x is preferably shorter than the length of the first section 11 . By setting the length of the connecting portion 23 in this way, the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be reduced only in a part of the first section 11 in the longitudinal direction x. , the time required for inflation of the balloon 30 can be set appropriately. The length of the connection portion 23 in the longitudinal direction x may be 4% or more, 7% or more, or 10% or more of the length of the first section 11, or 20% or less, or 18% or less. , may be as large as 15% or less.

The maximum outer diameter of the connection portion 23 may be 80% or more, 82% or more, 85% or more of the minimum inner diameter of the outer shaft 10 in the first section 11, or 98% or less, 95% or less, It may be as large as 90% or less.

In FIG. 2, the entire connecting portion 23 is arranged within the first section 11 in the longitudinal direction x. Thus, it is preferable that the distal end 23a of the connecting portion 23 is located closer to the distal end 11a of the first section 11 than the distal end 23a. Moreover, it is preferable that the proximal end 23b of the connecting portion 23 is positioned further distally than the proximal end 11b of the first section 11 . The connecting portion 23 may be arranged so as to overlap the central position 11c of the first section 11 in the longitudinal direction x.

Although not shown, the connecting portion 23 may exist to a position proximal or distal to the first section 11 in the longitudinal direction x. The distal end 23 a of the connecting portion 23 may be positioned distally from the first section 11 , and the proximal end 23 b of the connecting portion 23 may be positioned proximally from the first section 11 .

Although the entire connecting portion 23 is covered with the reduced diameter portion 14 in the longitudinal direction x in FIG. 3 , only a part of the connecting portion 23 may be covered with the reduced diameter portion 14 . Alternatively, the proximal end 23b of the connecting portion 23 may be located on the distal side of the distal end 14a of the reduced diameter portion 14, and the connecting portion may be positioned on the proximal side of the proximal end 14b of the reduced diameter portion 14. A distal end 23a of 23 may be located. With this configuration, the size of the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be controlled using the connecting portion 23 and the reduced diameter portion 14 .

The outer diameter of the connection portion 23 may be constant in the longitudinal direction x, or may vary depending on the position in the longitudinal direction x. For example, the connecting portion 23 may have a portion whose outer diameter is reduced toward the distal end 23a of the connecting portion 23 .

It is preferable that a portion of the first section 11 where the inner shaft 20 has the maximum outer diameter be located at the connecting portion 23 . With this configuration, the effect of controlling the flow of fluid in the connecting portion 23 can be enhanced.

The maximum outer diameter of connecting portion 23 is preferably smaller than the minimum inner diameter of outer shaft 10 in first section 11 . With this configuration, in the lumen 10c of the outer shaft 10, fluid can pass from the non-connecting portion 21a side to the non-connecting portion 22a side, or from the non-connecting portion 22a side to the non-connecting portion 21a side. That is, even if the connecting portion 23 exists, the inner cavity 10c of the outer shaft 10 is not closed.

The connecting portion 23 may be positioned at a portion of the outer shaft 10 in the first section 11 that has the smallest inner diameter. With this configuration, the effect of controlling the flow of fluid in the connecting portion 23 can be enhanced.

The outer surface of the connecting portion 23 may be in contact with the inner surface of the outer shaft 10 as long as fluid can pass between the non-connecting portion 21a, the connecting portion 23, and the non-connecting portion 22a. For example, a portion of the connecting portion 23 may be fixed to the inner surface of the outer shaft 10 . As a result, the inner shaft 20 can be fixed to the outer shaft 10 so as not to move.

The balloon 30 is positioned distally of the connecting portion 23 . The expression that the balloon 30 is located on the distal side of the connecting portion 23 means that the proximal end of the expanded portion of the balloon 30 is located on the distal side of the connecting portion 23 . The expanded portion of the balloon 30 refers to the portion of the balloon 30 that is expanded by fluid, excluding the portion attached to the shaft 2 . The expansion section includes, for example, a proximal taper section, a distal taper section, and a straight tube section of the balloon 30 . This makes it easier to control the flow of fluid supplied to the inside of the balloon 30 using the connecting portion 23 .

As shown in FIG. 4, the connecting portion 23 is preferably located at the proximal portion 11e of the first section 11. As shown in FIG. In other words, the distal end 23a of the connecting portion 23 may be positioned closer to the proximal side than the central position 11c of the first section 11 in the longitudinal direction x. This configuration facilitates flow control during the early stages of fluid delivery to balloon 30 .

As shown in FIG. 5, the connecting portion 23 may be located at the distal portion 11d of the first section 11. As shown in FIG. In other words, the proximal end 23b of the connecting portion 23 may be located on the distal side of the central position 11c of the first section 11 in the longitudinal direction x. This configuration makes it easier to control the flow at the end of the fluid supply path to the balloon 30 compared to the aspect in which the connecting portion 23 is located at the proximal portion 11 e of the first section 11 .

As shown in FIG. 6 , the outer shaft 10 preferably has a second section 12 arranged proximally adjacent to the first section 11 and having a larger inner diameter than the first section 11 . Specifically, in the outer shaft 10 , the minimum inner diameter of the second section 12 is preferably larger than the maximum inner diameter of the first section 11 , and the average inner diameter of the second section 12 is greater than the average inner diameter of the first section 11 . It is more preferable that the inner diameter of the second section 12 is larger than the maximum inner diameter of the first section 11 over the entire longitudinal axis direction of the second section 12 . With this configuration, the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be made larger in the second section 12 than in the first section 11 . As a result, it becomes easier to control the flow of fluid in the first section 11 . The central position of the outer shaft 10 in the longitudinal direction x may be in the second section 12 .

The outer diameter of the second section 12 of the outer shaft 10 may be different from the outer diameter of the first section 11, or may be the same as shown in FIG. In order to control the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 , the outer diameter of the second section 12 of the outer shaft 10 is preferably larger than the outer diameter of the first section 11 . The outer diameter of the second section 12 may not be constant. The second section 12 may, for example, have a tapered shape that tapers from the proximal side to the distal side.

In the outer shaft 10 , the thickness of the second section 12 may be different from the thickness of the first section 11 . For example, as shown in FIG. 7, the thickness of the first section 11 of the outer shaft 10 may be greater than the thickness of the second section 12 . Thereby, the inner diameter of the first section 11 can be made smaller than that of the second section 12 .

Although not shown, the outer shaft 10 may have a tubular shaft body and an inner tubular member disposed distally and inside the shaft body. In that case, the portion where the inner cylinder member is arranged can be the first section 11 . The inner cylinder member may be made of resin or metal. Further, the outer shaft 10 may have a cylindrical shaft body, and a resin layer or a metal layer may be arranged on the inner surface of the shaft body. In this case, the portion where the resin layer or the metal layer is arranged can be the first section 11 . With such a configuration as well, the inner diameter of the first section 11 of the outer shaft 10 can be made smaller than the inner diameter of the second section 12 .

It is preferable that the connecting portion 23 is not arranged in the second section 12 . With this configuration, it is possible to efficiently control the flow of fluid in the first section 11 . Note that the connecting portion 23 may extend to the inside of the expanded portion of the balloon 30 . The flow rate required to inflate the balloon 30 can be reduced.

The expanded outer diameter of the balloon 30 is preferably smaller than the maximum outer diameter of the outer shaft 10 at the second section 12 . Further, when the outer diameters of the first section 11 and the second section 12 are different, the outer diameter of the balloon 30 during expansion may be smaller than the outer diameter of the distal end of the outer shaft 10 in the second section 12. good. By setting the outer diameters of the balloon 30 and the outer shaft 10 in this way, it becomes easier to use the catheter 1 inside a very thin body cavity.

The length of the first section 11 in the longitudinal direction x is preferably shorter than the length of the second section 12 . By setting the length of the first section 11 in this way, the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be reduced only in a part of the first section 11 in the longitudinal direction x. Therefore, the time required for expanding the balloon 30 can be appropriately set.

As shown in FIG. 6, when the outer shaft 10 has a second section 12 arranged adjacent to and proximal to the first section 11 and having a larger inner diameter than the first section 11, the outer shaft 10 preferably has a step 15 at the boundary between the first section 11 and the second section 12 . Since the cross-sectional area of the space between the outer shaft 10 and the inner shaft 20 can be rapidly changed by the step 15, the flow of fluid in the first section 11 can be easily controlled.

The inner diameter of the outer shaft 10 at the distal end of the second section 12 is 1.02 times or more, 1.05 times or more, 1.1 times the inner diameter of the outer shaft 10 at the proximal end 11b of the first section 11. 1.5 times or less, 1.4 times or less, or 1.3 times or less.

As shown in FIG. 6, in a rapid exchange balloon catheter, the proximal end 20b of the inner shaft 20 preferably coincides with the proximal end 12b of the second section 12. Thus, the inner shaft 20 may not exist on the proximal side of the second section 12 . The outer shaft 10 is composed of a distal tubular member and a proximal tubular member, the inner shaft 20 is arranged in the distal tubular member, and the proximal end of the inner shaft 20 is connected to the proximal tubular member of the outer shaft 10 . A guidewire port 41 can be formed by joining the distal end of the material and opening the side of the outer shaft 10 . In an over-the-wire balloon catheter, inner shaft 20 may extend to a guidewire port in hub 40 .

The inner diameter of the outer shaft 10 may be constant in the second section 12 . The second section 12 may have a portion where the inner diameter of the outer shaft 10 is reduced toward the distal end 10a or a portion where it is increased.

The outer diameter of the inner shaft 20 may be constant in the second section 12 . The second section 12 may have a portion in which the outer diameter of the inner shaft 20 is reduced toward the distal end 10a, or a portion in which it is increased.

As shown in FIG. 6, when the outer shaft 10 has a second section 12 arranged adjacent to the first section 11 on the proximal side and having a larger inner diameter than the first section 11, the inner shaft 20 is The maximum outer diameter of the outer shaft 10 in the first section 11 is 80% or more of the maximum inner diameter of the outer shaft 10 in the second section 12, and the maximum outer diameter of the inner shaft 20 in the second section 12 is the maximum outer diameter of the outer shaft 10 in the second section 12. It is preferably 70% or less of the inner diameter. With this configuration, the flow of fluid is moderately regulated in the first section 11, and the fluid easily flows smoothly in the second section 12. As shown in FIG.

The maximum outer diameter of the inner shaft 20 may be 82% or more, 85% or more, or 98% or less, 95% or less, or 90% or less of the maximum inner diameter of the outer shaft 10 in the first section 11. Permissible.

The maximum outer diameter of the inner shaft 20 in the second section 12 may be 40% or more, 45% or more, 50% or more, 65% or less, or 60% of the maximum inner diameter of the outer shaft 10 in the second section 12. % or less.

As shown in FIG. 6 , the outer shaft 10 may have a third section 13 in which the inner shaft 20 is not present on the proximal side of the second section 12 . The third section 13 may be arranged adjacent to the second section 12 . For example, a rapid exchange balloon catheter may have a third section 13 . The central position of the outer shaft 10 in the longitudinal direction x may be in the third section 13 .

The outer diameter of the outer shaft 10 may be constant in the third section 13 . The outer shaft 10 may have a portion in the third section 13 where the outer diameter of the outer shaft 10 decreases toward the distal end 10a. The outer shaft 10 may be formed by connecting a plurality of tubes in the longitudinal axis direction x in the third section 13 . The maximum outer diameter of the third section 13 may be the same as or larger than the maximum outer diameter of the second section 12 . A proximal portion of the third section 13 may be connected to the hub 40 .

As shown in FIG. 6, the distal end of inner shaft 20 may be provided with a protective tip 42 . A protective tip 42 preferably covers the distal end of inner shaft 20 . The protective tip 42 may have a cylindrical shape. The distal end of protective tip 42 is preferably a distal guidewire port.

A radiopaque marker may be placed on the portion of the shaft 2 where the balloon 30 is located to allow the location of the balloon 30 to be confirmed under X-ray fluoroscopy. A radiopaque marker 43 is attached to the outer side of the inner shaft 20 in FIG. Protective tip 42 may be a radiopaque marker. The radiopaque marker is preferably arranged distally of the first section 11 . One or more markers can be placed on the catheter 1 .

1: Catheter 2: Shaft 10: Outer shaft 11: First section 11d: Distal section 11e: Proximal section 12: Second section 14: Reduced diameter section 15: Step 20: Inner shaft 21: First tube 22: Second section 2 cylinders 23: connection part 30: balloon x: longitudinal axis direction

Claims (12)

a shaft having a longitudinal distal end and a proximal end;
a balloon disposed distally of the shaft;
the shaft has an outer shaft having a lumen extending in the longitudinal direction and an inner shaft disposed in the lumen of the outer shaft;
the outer shaft has at its distal portion a first section having an inner diameter smaller than the inner diameter at the central position of the outer shaft in the longitudinal direction;
The inner shaft has a first tube and a second tube positioned closer to the proximal side than the first tube, and the first tube and the second tube are connected to each other at a connecting portion, and the A catheter with a connection located in the first section. 2. The catheter of claim 1, wherein said connecting portion is located proximally of said first section. 3. A catheter according to claim 1 or 2, wherein the connecting portion is located distally of the first section. The catheter according to any one of claims 1 to 3, wherein the second tube is inserted into the lumen of the first tube in the connecting portion. The catheter according to any one of claims 1 to 4, wherein the inner diameter of the outer shaft is constant in the first section. The catheter according to any one of claims 1 to 4, wherein the outer shaft has a reduced diameter portion in which the inner diameter of the outer shaft decreases toward the distal end side in the first section. . The outer shaft has a second section arranged adjacent to the proximal side of the first section and having a larger inner diameter than the first section,
The catheter according to any one of claims 1 to 6, wherein the outer shaft has a step at the boundary between the first section and the second section. the inner shaft extends from the distal end of the outer shaft;
a distal end of the balloon is secured to the inner shaft;
A catheter according to any preceding claim, wherein the proximal end of the balloon is secured to the first section of the outer shaft. A catheter according to any preceding claim, wherein the length of the first section in the longitudinal direction is greater than the length of the balloon. The catheter according to any one of claims 1 to 9, wherein the outer diameter of the balloon when expanded is smaller than the maximum outer diameter of the shaft. The outer shaft has a second section arranged adjacent to the proximal side of the first section and having a larger inner diameter than the first section,
The catheter according to any one of claims 1 to 10, wherein the outer diameter of the balloon when expanded is smaller than the maximum outer diameter of the outer shaft in the second section. The outer shaft has a second section arranged adjacent to the proximal side of the first section and having a larger inner diameter than the first section,
The maximum outer diameter of the inner shaft is 80% or more of the maximum inner diameter of the outer shaft in the first section,
The catheter according to any one of claims 1 to 11, wherein the maximum outer diameter of the inner shaft in the second section is 70% or less of the maximum inner diameter of the outer shaft in the second section.

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