WO2018062116A1 - Balloon catheter - Google Patents

Abstract

A balloon catheter (10) is provided with: a shaft (1) that distributes an expansion fluid through a leading end-side opening (1c); and a balloon (2) that has a first fixing part (2A) which is fixed on an outer peripheral surface (1e) of the shaft (1) at a location closer to the leading end side than the leading end-side opening (1c), a second fixing part (2C) which is fixed on the outer peripheral surface (1e) of the shaft (1) at a location closer to the base end side than the leading end-side opening (1c), and an expandable diameter part (2B) which is formed between the first fixing part (2A) and the second fixing part (2C), and which expands in diameter by the expansion fluid, wherein the expandable diameter part (2B) is configured to have a first end part (2D), a central part (2E), and a second end part (2F) disposed adjacent to each other in this sequence, and the material for the first end part (2D) and the second end part (2F) has a 100% modulus lower than that of the material for the central part (2E).

Description

Balloon catheter

The present invention relates to a balloon catheter.
Priority is claimed on Japanese Patent Application No. 2016-190533, filed September 29, 2016, the content of which is incorporated herein by reference.

For example, a balloon catheter is known as a treatment tool used with a medical endoscope or the like. A balloon catheter is used for the purpose of, for example, expanding a stenosis such as a digestive tract and securing a lumen, and includes an expandable balloon.
In a balloon of a balloon catheter, pressure resistance against pressure applied during expansion and positional deviation prevention performance during expansion are required.
For example, Patent Document 1 describes a balloon for expanding a constriction part (balloon catheter) that can prevent positional deviation from a constriction part at the time of balloon expansion by the dog-bone shape of the expanded state of the naturally expanded state. There is.
For example, Patent Document 2 describes a balloon catheter provided with a balloon that becomes substantially cylindrical at the time of expansion by reducing the thickness of both end portions in the longitudinal direction as compared with the thickness of the central portion.

Japanese Patent Application Laid-Open No. 2001-009037 Japanese Unexamined Patent Publication No. 2010-201007

However, the conventional balloon catheter as described above has the following problems.
In the technique described in Patent Document 1, since the balloon has a dog bone-shaped three-dimensional shape, when folded, the outer diameter after folding is not due to the overlapping of the balloon near the dog bone without being flat feathered. It gets bigger. Therefore, the outer diameter of the balloon at the time of folding becomes large, and the variation in the outer diameter in the longitudinal direction becomes large. With such a folded configuration, the insertion and removal performance when inserting and removing a folded balloon into and from a lumen, or when inserting and removing a folded balloon into a tube such as an endoscope for guiding the balloon into the lumen There is a problem that
In the technique described in Patent Document 2, there is a problem that the pressure resistance of the both end portions in the longitudinal direction is reduced in order to reduce the thickness of the both end portions in the longitudinal direction of the balloon.
It is also conceivable to further increase the thickness of the central portion in order to increase the pressure resistance of both end portions. However, in this case, the outer diameter of the central portion is increased when the balloon is folded. For this reason, there is a problem that the insertion and extraction performance is lowered when inserting and removing the folded balloon from the lumen or inserting and extracting from the tube member such as an endoscope for guiding the folded balloon to the lumen. is there.

The present invention has been made in view of the above problems, and provides a balloon catheter capable of suppressing axial displacement during attachment to a lumen without reducing the pressure resistance and insertion / extraction performance of the balloon. The purpose is to

In order to solve the above-mentioned problems, the balloon catheter according to the aspect of the present invention is fixed to a shaft that circulates the expansion fluid through the distal end opening, and to the distal end side of the outer periphery of the shaft than the distal end opening. Formed between the first fixing portion and the second fixing portion, and the first fixing portion and the second fixing portion fixed on the outer peripheral portion of the shaft at the base end side with respect to the distal end side opening portion. And a balloon having an enlarged diameter portion expanded by the expansion fluid supplied from the distal end side opening portion, the enlarged diameter portion moving from the first fixed portion toward the second fixed portion. , The first end, the central portion, and the second end are adjacent to each other in this order, and 100% modulus of the material of the first end and the second end is the material of the central portion. Less than 100% modulus.

In the balloon catheter, the length in the longitudinal direction of the shaft of the first end and the second end is 15% or more and 25% or less of the length in the longitudinal direction of the shaft of the enlarged diameter portion It is also good.

In the above balloon catheter, the breaking strength of the material of the first end and the second end may be 80% or more of the breaking strength of the material of the central part.

In the above-mentioned balloon catheter, in the natural expansion state of the enlarged diameter portion in which the enlarged diameter portion is expanded without generation of stress, the maximum outer diameter of the first end portion, the central portion, and the second end portion The diameters may be equal to one another.

In the above-mentioned balloon catheter, in the natural expansion state of the enlarged diameter portion in which the enlarged diameter portion is expanded without generating stress, the first end portion and the second end portion are directed to the central portion, respectively. Has a diameter transition portion in which the outer diameter increases in the direction, and a constant diameter portion extending at a constant diameter from the portion which becomes the maximum outer diameter of the diameter transition portion, and the outer shape of the diameter transition portion is a bowl shape Good.

ADVANTAGE OF THE INVENTION According to the balloon catheter of this invention, it is effective in the ability to suppress the position shift of the axial direction at the time of mounting | wearing to a lumen | rumen, without reducing the pressure resistance and insertion / extraction performance of a balloon.

It is a typical fragmentary sectional view showing an example of the composition in the natural deployment state of the balloon catheter of an embodiment of the present invention. It is a typical graph which shows an example of the change of the thickness of the balloon of the balloon catheter of embodiment of this invention. It is a typical fragmentary sectional view showing an example of the composition in the diameter expansion state of the balloon catheter of an embodiment of the present invention. It is a typical front view in the natural deployment state of the balloon catheter of a comparative example. It is a typical front view in the diameter-expanded state of the balloon catheter of a comparative example. It is a schematic cross section which shows the shape of the constriction part used for evaluation of position shift.

A balloon catheter according to an embodiment of the present invention will be described.
FIG. 1 is a schematic partial cross-sectional view showing an example of the configuration of the balloon catheter according to the embodiment of the present invention in a naturally-deployed state. FIG. 2 is a schematic graph showing an example of the change in the wall thickness of the balloon of the balloon catheter according to the embodiment of the present invention.

As shown in FIG. 1, the balloon catheter 10 of the present embodiment is an elongated member extending along the central axis O from the proximal end on the right side to the distal end on the left side. The balloon catheter 10 is used by being inserted from the tip into the lumen of a patient.
The balloon catheter 10 comprises a shaft 1 and a balloon 2. As described below, the balloon 2 can be expanded and contracted.
FIG. 1 shows the expanded state of the balloon 2 in a natural unfolded state. The naturally deployed state of the balloon 2 is defined as the maximum state in which the balloon 2 is expanded without generating tension (stress) in a state in which the balloon 2 is fixed to the shaft 1.
In the following, the state in which the balloon 2 is expanded more than the naturally expanded state is referred to as the “expanded state”.
Although not shown, the balloon 2 is contracted in the initial state before the balloon catheter 10 is inserted into the lumen, and the outer periphery of the shaft 1 is folded in a plurality of thin wings. It is wrapped around the department. The balloon 2 has a fold or crease (hereinafter, referred to as a fold or the like) by a known folding process or the like in advance so that the initial state is restored when the balloon 2 contracts after expanding.
The balloon catheter 10 in the initial state is an elongated member having generally the same outer diameter.

The type of lumen into which the balloon catheter 10 is inserted is not limited. For example, the balloon catheter 10 may be inserted into the digestive tract, esophagus, bile duct, urethra, blood vessels and the like. However, in the balloon catheter 10, the outer diameter in the initial state of the balloon catheter 10, the maximum outer diameter in the natural deployed state of the balloon 2 and the outer diameter in the expanded state of the balloon 2 correspond to the inner diameter of the lumen to be inserted. Are set in advance so as to have the required dimension values.

In the following, when describing the relative positions along the central axis O in the balloon catheter 10 and the members constituting the balloon catheter 10, the portion closer to the tip of the balloon catheter 10 is the tip, and the portion closer to the proximal end is the proximal There is a case to say.
In the present specification, for example, when describing the relative position of a member such as an axial or cylindrical member capable of specifying an axis such as the central axis O, a direction along the axis is an axial direction and a circumferential direction is a circumferential direction A direction along a line intersecting the axis in a plane orthogonal to the axis is referred to as a radial direction.

The shaft 1 is an elongated member extending along the central axis O from the proximal end to the distal end of the balloon catheter 10. The longitudinal direction of the shaft 1 coincides with the axial direction along the central axis O. The shaft 1 is formed of a flexible resin material.
The shaft 1 may be formed by a single tube or may be formed by a plurality of tubes.
The shaft 1 in the present embodiment includes, as an example, an inner tube 1B and an outer tube 1A. For example, if the shaft 1 is formed of a single tube, a multi-lumen tube or the like may be used.

The inner tube 1 B is a tubular member extending over the entire length of the shaft 1. The outer shape of the inner tube 1B is not limited. In the present embodiment, as an example, the outer peripheral surface 1 e of the inner tube 1 B is circular with the central axis O as a center in a cross section orthogonal to the central axis O.
In the inside of the inner tube 1B, a through hole axially penetrating along the central axis O is formed. This through hole may be used, for example, for the purpose of inserting a guide wire or flowing a drug to be supplied to a lumen. The inner diameter of the inner circumferential surface 1f of the through hole is set to an appropriate size according to the application.
In the present embodiment, the through hole inside the inner tube 1B does not penetrate the outer peripheral surface 1e.
The outer diameter of the outer peripheral surface 1e is set to a size that allows an inner tube 1B to be inserted by opening a gap inside an outer tube 1A described later.

The outer tube 1A is a pipe member through which the inner tube 1B is inserted. The length of the outer tube 1A is shorter than the length of the inner tube 1B. For this reason, the inner tube 1B inserted into the outer tube 1A extends to the tip side more than the tip of the outer tube 1A.
In FIG. 1, although the proximal end of the outer tube 1A and the proximal end of the inner tube 1B are drawn to be in line, this is an example. For example, the inner tube 1B may extend to the proximal end side of the outer tube 1A, or the outer tube 1A and the inner tube 1B may branch to each other on the proximal end side.
The outer shape of the outer tube 1A is not limited. In the present embodiment, as an example, the outer peripheral surface 1a of the outer tube 1A has a circular shape centered on the central axis O in a cross section orthogonal to the central axis O.
In the inside of the outer tube 1A, a through hole penetrating in the axial direction is formed. An internal flow path P having an annular cross section surrounding the outer peripheral surface 1 e is formed between the inner peripheral surface 1 b of the through hole and the outer peripheral surface 1 e of the inner tube 1 B inserted into the inside.
The outer diameter of the outer peripheral surface 1a of the outer tube 1A is smaller than the inner diameter of the lumen into which the shaft 1 is to be inserted.

In the internal flow path P, an expansion fluid (not shown) for expanding the balloon 2 described later can flow. The expanding fluid may be liquid or gas. In the following, an example in which the expansion fluid is made of warm water will be described.
The internal flow path P communicates with the outside through the proximal end opening 1d on the proximal end side of the outer tube 1A and the inner tube 1B and the distal end opening 1c on the distal end side of the outer tube 1A.
The proximal end opening 1 d is connectable to an expansion fluid supply unit (not shown).
The distal end side opening 1 c communicates with the inside of a balloon 2 described later.

Examples of the material of the shaft 1 include nylon, polyamide, PTFE (polytetrafluoroethylene) and the like.

The balloon 2 is a member which is formed of a thin film and becomes tubular in an expanded state. The tip of the shaft 1 is inserted into the balloon 2.
The balloon 2 includes a first fixing portion 2A, an enlarged diameter portion 2B, and a second fixing portion 2C from the distal end side to the proximal end side.

The first fixing portion 2A is a cylindrical portion fixed in close contact with the outer peripheral surface 1e of the inner tube 1B at the end of the inner tube 1B which is closer to the end than the end opening 1c. The fixing method of the 1st fixing | fixed part 2A and the outer peripheral surface 1e can be a suitable fixing method which can seal the fluid for expansion. For example, the first fixing portion 2A may be welded to the outer peripheral surface 1e.
The length of the first fixing portion 2A in the axial direction is represented by L _2A . The length L _2A is set to an appropriate length such that the fixing strength required for the first fixing portion 2A can be obtained.

The enlarged diameter portion 2B has a cylindrical shape larger in diameter than the outer peripheral surface 1e which can be deformed between the state of being separated and expanded from the outer peripheral surface 1e of the inner tube 1B and the contracted state contacting or close to the outer peripheral surface 1e. It is a department.
Below, the shape of the enlarged diameter part 2B in a natural expansion | deployment state is demonstrated first.

The enlarged diameter portion 2B includes a first end 2D, a central portion 2E, and a second end 2F from the distal end side to the proximal end side. The first end 2D, the center 2E, and the second end 2F are adjacent in this order.
The length of the enlarged diameter portion 2B in the axial direction is represented by L _2B .

The first end 2D includes a diameter transition portion 2a and a constant diameter portion 2b from the distal end side to the proximal end side. The lengths of the diameter transition portion 2a and the constant diameter portion 2b in the axial direction are represented by L _2a and L _2b , respectively. However, the first end 2D may be configured of only the diameter transition portion 2a.
In the following description, it is assumed that the length L 2 b of the constant diameter portion 2 _b is 0 or more so that the case where the constant diameter portion 2 b is not included can be included. L 2 _b = 0 corresponds to the case where the constant diameter portion 2 b is not provided. In this case, the constant diameter portion 2b in the following description may be read as the base end of the diameter transition portion 2a.

The diameter transition portion 2a is a cylindrical portion whose outer diameter gradually increases from the base end of the first fixed portion 2A toward the base end. The outer shape of the diameter transition portion 2a may be a strict conical surface in which the rate of change of the outer diameter in the axial direction is constant, or the rate of change of the outer diameter changes the outer side of the conical surface. Or it may be variously curved inward. The diameter transition portion 2a may have, for example, a bowl shape, a shell shape, a bell shape, a funnel shape, a trumpet shape or the like. The cross-sectional shape in the radial direction of the diameter transition portion 2a may be a rounded C-shape at the tip or a V-shape with a tapered tip.
As an example, as the diameter transition part 2a shown in FIG. 1 goes from the first fixed part 2A toward the central part 2E described later, the rate of change of the outer diameter is monotonous from the positive maximum value to the zero or more minimum value. Is a template that reduces to That is, the outer shape of the diameter transition portion 2a shown in FIG. 1 is a convex curved surface which bulges outside the conical surface connecting the tip and the proximal end, and has a shape close to a partial spherical surface.

The constant diameter portion 2 _{b is} a cylindrical portion of a length L 2 _b whose outer diameter matches the diameter of the proximal end of the diameter transition portion 2 a. The fixed diameter portion 2b is connected to the base end of the diameter transition portion 2a without any level difference (however, for example, minute irregularities generated in manufacturing such as parting line etc. are excluded). The outer diameter of the constant diameter portion 2b is represented by D ₀ in the natural deployed state.
The tip end of the fixed diameter portion 2b is smoothly connected to the base end of the diameter transition portion 2a in the axial direction when the rate of change of the outer diameter at the base end of the diameter transition portion 2a is zero. The tip of the fixed diameter portion 2b is connected to form a bent portion with the base end of the diameter transition portion 2a when the rate of change of the outer diameter at the base end of the diameter transition portion 2a is a positive value.
In FIG. 1, as an example, the case where the rate of change of the outer diameter at the base end of the diameter transition portion 2a is 0 and the diameter transition portion 2a and the constant diameter portion 2b are connected smoothly is illustrated.

The diameter transition portion 2a and the constant diameter portion 2b of the first end portion 2D are all formed of the same material. The material of the first end 2D may be different from the material of the first fixing portion 2A, but in the present embodiment, as an example, the first end 2D and the first fixing portion 2A are formed of similar materials. It is done.
The material of the first end 2D has a breaking strength not to be broken even by the internal pressure applied to the expanded balloon 2 and has a 100% modulus lower than the 100% modulus of the material of the central portion 2E described later A resin material is used.
The breaking strength of the material of the first end 2D is more preferably 80% or more of the breaking strength of the material of the central portion 2E described later.
As the resin material used for the first end 2D, all materials conventionally used for the balloon of the balloon catheter can be used as long as the above-mentioned conditions are satisfied. As a material of 1st end part 2D, a thermoplastic polyamide system elastomer, polyethylene (PE), a thermoplastic polyurethane elastomer (PTU) etc. are mentioned, for example.

The central portion 2E is a cylindrical portion connected to the base end of the first end portion 2D without any level difference (however, for example, minute irregularities generated in manufacturing such as parting lines are excluded). In the example shown in FIG. 1, the outer shape of the naturally developed state of the central portion 2E is the same as the outer diameter D of the proximal end of the first end 2D, corresponding to the first end 2D having a circular cross section. It is a cylindrical surface of ₀ . The length of the central portion 2E in the axial direction is represented by L _2E .
Here, since FIG. 1 is a schematic view, the first end 2D and the central portion 2E are drawn as being joined via a joint 2e along a plane orthogonal to the central axis O. However, the joint portion 2e between the first end portion 2D and the central portion 2E may be deviated from a plane orthogonal to the central axis O or may be corrugated for manufacturing reasons to be described later. Furthermore, at the joint 2e between the first end 2D and the central portion 2E, the material of the first end 2D and the material of the central portion 2E are mixed for a manufacturing reason to be described later, and a clear boundary is It does not have to appear. In these cases, the position of the joint 2e related to the length of the first end 2D and the central portion 2E in the axial direction is defined as the position of a plane orthogonal to the central axis O so as to average these material distributions. Ru.

The material of the central portion 2E has a breaking strength not to be broken even by the internal pressure applied to the expanded balloon 2 at the time of use, and 100% modulus of the material of the first end 2D and the second end 2F described later Materials having a higher 100% modulus are used.
As the resin material used for the central portion 2E, all the materials conventionally used for the balloon of the balloon catheter can be used, as well as the materials usable for the first end 2D, as long as the above-mentioned conditions are satisfied.

The second end portion 2F includes a constant diameter portion 2c and a diameter transition portion 2d from the distal end side to the proximal end side. The lengths of the constant diameter portion 2c and the diameter transition portion 2d in the axial direction are respectively represented by L _2c and L _2d . However, the 2nd end 2F may be constituted only by diameter transition part 2d. In the following, as in the case of the constant diameter portion 2b, the length of the constant diameter portion 2c is also described as being 0 or more. L _{2 c} = 0 corresponds to the case where the constant diameter portion 2 c is not provided. In this case, unless otherwise specified, the constant diameter portion 2c in the following description is read as the tip of the diameter transition portion 2d.

The distal end of the second end 2F is connected to the proximal end of the central portion 2E without any step (except, for example, minute irregularities generated in manufacturing such as a parting line). In FIG. 1, a joint 2f between the second end 2F and the central part 2E is schematically drawn in the same manner as the joint 2e. The joint 2 f can have the same shape as the joint 2 e. The position of the joint 2f related to the length of the second end 2F and the central part 2E in the axial direction is the same as the joint 2e, and the material distribution of the material of the second end 2F and the material of the central part 2E is averaged. Is defined as the position of a plane orthogonal to the central axis O.

The constant diameter portion 2c and the diameter transition portion 2d in the second end portion 2F have the same shape as the constant diameter portion 2b and the diameter transition portion 2a in the first end portion 2D, respectively. However, the diameter transition part 2d is a cylindrical part whose outer diameter gradually reduces as it goes from the base end of the central part 2E to the base end side.
For example, the constant diameter portion 2c and the diameter transition portion 2d of the second end portion 2F may have the same shape as the constant diameter portion 2b and the diameter transition portion 2a at the first end portion 2D, respectively, except for the direction.
For example, in the constant diameter portion 2c and the diameter transition portion 2d of the second end portion 2F, the length in the axial direction or the rate of change of the outer diameter at the diameter transition portion 2d is the diameter of the constant diameter portion 2b of the first end portion 2D. It may be different from the transition part 2a.
In the present embodiment, as an example, the shape of the second end 2F will be described as a shape that is plane-symmetrical to the first end 2D with respect to a plane orthogonal to the central axis O. Therefore, unless otherwise specified, L _2a = L _2d and L _2b = L _2c .

The constant diameter portion 2c and the diameter transition portion 2d of the second end portion 2F are formed of the same material. The material of the second end 2F may be different from or the same as the material of the first end 2D.
Similar to the first end 2D, the material of the second end 2F has a breaking strength not to be broken even by the internal pressure applied to the expanded balloon 2, and 100% modulus of the material of the central portion 2E described later Materials with lower 100% modulus are used.
The breaking strength of the material of the second end 2F is, like the material of the first end 2D, more preferably 80% or more of the breaking strength of the material of the central portion 2E.
As the resin material used for the second end 2F, all materials conventionally used for the balloon of the balloon catheter can be used, as well as the materials usable for the first end 2D, provided that the above conditions are satisfied. is there.

The second fixing portion 2C is connected to the proximal end of the second end 2F, and is fixed in close contact with the outer peripheral surface 1a of the outer tube 1A at the distal end of the outer tube 1A which is proximal to the distal end side opening 1c. It is a cylindrical part that has been As a method of fixing the second fixing portion 2C and the outer peripheral surface 1a, an appropriate fixing method capable of sealing the expansion fluid is possible. For example, the second fixing portion 2C may be welded to the outer peripheral surface 1a.
The length of the second fixed portion 2C in the axial direction is represented by L _2C . The length L _{2 C} is set to an appropriate length such that the fixing strength required for the second fixing portion 2 C can be obtained.

With such a configuration, in the balloon 2 in a naturally deployed state, the length L _2B of the enlarged diameter portion 2B in the axial direction is the length of the first end 2D, the central portion 2E, and the second end 2F in the axial direction (L _2a + L _2b + L _2E + L _2c + L _2d ).
The length _L2B is set to an appropriate length that can expand the narrowing of the lumen into which the balloon 2 is inserted.
The lengths of the first end 2D and the second end 2F in the axial direction (longitudinal direction of the shaft 1) may be 15% or more and 25% or less of the length of the enlarged diameter portion 2B in the axial direction. .
The lengths of the first end 2D and the second end 2F in the axial direction may be equal to the maximum outer diameters of the first end 2D and the second end 2F in the expanded state.

As described above, the balloon 2 is closely fixed to the outer peripheral surfaces 1e and 1a, which are the outer peripheral portions of the distal end portion of the shaft 1, by the first fixing portion 2A and the second fixing portion 2C. Inside the enlarged diameter portion 2B, around the outer peripheral surface 1e on the tip side with respect to the tip side opening 1c, an internal space S through which the expansion fluid flows in and out through the tip side opening 1c is formed.
When the expansion fluid flows into the internal space S through the distal end opening 1c, the enlarged diameter portion 2B expands. At that time, since the expansion fluid introduced into the internal space S is sealed by the first fixing portion 2A and the second fixing portion 2C, the internal pressure of the internal space S rises.
When the expansion fluid in the internal space S is discharged to the internal flow path P through the distal end opening 1c, the enlarged diameter portion 2B contracts.
Since the enlarged diameter portion 2B is creased or the like as described above, the folded shape in the initial state is restored as it is contracted.

The balloon 2 may be manufactured, for example, by blow molding using a mold that transfers the shape in a naturally developed state.
For example, a parison tube in which a forming material of the first fixing portion 2A and the first end 2D, a forming material of the central portion 2E, and a forming material of the second end 2F and the second fixing portion 2C are joined in this order The parison tube is manufactured and placed in the interior of the mold described above to effect blow molding. That is, when the parison tube is expanded toward the inner surface of the mold and brought into close contact with the molding surface of the mold and cured, the shape of the molding surface is transferred as the outer shape of the expanded parison tube. Thereby, the balloon 2 is manufactured.

The expanded parison tube is thinned according to the diameter expansion rate. However, due to the variation in thickness of the parison tube, the variation in deformation of the parison tube at the time of expansion, and the like, the thickness at the time of expansion may also vary.
Manufacturing variations of the balloon 2 may also occur in the axial direction. For example, the dissimilar material joint in the parison tube before expansion may not necessarily be formed along a plane orthogonal to the axial direction. In addition, in the blow molding, since there is a possibility that the deformation in the axial direction may also vary during expansion, the axial position of the joint portion of the different material may change during the expansion.
Depending on these manufacturing fluctuation factors, in the balloon 2, the shapes of the joints 2e and 2f deviate from the shape along the plane orthogonal to the central axis O as schematically shown in FIG. There is also.

FIG. 2 schematically shows an example of the thickness distribution in the axial direction of a balloon 2 manufactured from a constant thickness parison tube. The above-described manufacturing variations and variations in the thickness of each part are omitted in the illustration of FIG.
In FIG. 2, the horizontal axis represents the position of the balloon 2 in the axial direction, and the vertical axis represents the thickness.
The origin 0 on the horizontal axis corresponds to the position of the tip of the balloon 2 (the tip of the first fixing portion 2A). The point a indicates the position of the tip of the enlarged diameter portion 2B (the tip of the diameter transition portion 2a). The point b indicates the position of the boundary between the diameter transition portion 2a and the constant diameter portion 2b. A point c (d) indicates the position of the joint 2e (2f). A point e indicates the position of the boundary between the constant diameter portion 2c and the diameter transition portion 2d. Points b and e correspond to the positions of the parting line of the mold. The point f indicates the position of the proximal end of the enlarged diameter portion 2B (the proximal end of the diameter transition portion 2d). The point g indicates the position of the proximal end of the balloon 2 (the proximal end of the second fixed portion 2C).

As shown in FIG. 2, the wall thickness of the balloon 2 is substantially the same thickness t ₃ and the thickness of the parison tube at the proximal end of the tip and the second fixing portion 2C of the first fixing portion 2A. The proximal end of the first fixed portion 2A (the tip of the second fixed portion 2C) is stretched toward the center at the time of expansion, and thus decreases to a thickness t ₂ (where t ₂ <t ₃ ).
Since the diameter transition portion 2a (diameter transition portion 2d) gradually expands in diameter from the tip (base end) toward the central portion 2E, the thickness of the diameter transition portion 2a (diameter transition portion 2d) is gradually decreases from the thickness t ₂ from the end) toward the central portion 2E. In the vicinity of the fixed diameter portion 2b (fixed diameter portion 2c), since the rate of change of the outer diameter approaches 0, the rate of change of the thickness also decreases (see points a to b and points f to e).
It has a maximum outer diameter D ₀ in the enlarged diameter portion 2B, constant diameter portion 2b, a central portion 2E, in between points b ~ point e corresponding to the constant diameter portion 2c, the thickness of each, minimum thickness t _{1 (however, t} 1 <t ₂₎ it becomes.

The inner tube 1B is inserted into the outer tube 1A, and the first fixed portion 2A is on the outer peripheral surface 1e and the second fixed portion 2C is on the outer peripheral surface 1a. It is fixed to each by heat fusion etc.
The balloon 2 fixed to the shaft 1 is folded so as to make a fold or the like by a known folding process or the like, and is wound around the inner tube 1B. Thus, the balloon catheter 10 is manufactured.
In the initial state, the balloon 2 is folded so as to have an outer diameter substantially equal to the outer diameter of the shaft 1.

Next, the operation of the balloon catheter 10 will be described centering on the operation of the balloon 2 at the time of expansion.
FIG. 3 is a schematic partial cross-sectional view showing an example of the configuration of the balloon catheter according to the embodiment of the present invention in the expanded diameter state.

The balloon catheter 10 is, for example, a proximal end of a guide wire (not shown, the same applies hereinafter) inserted in advance to the placement position of the balloon 2 in the patient's body from the distal end side of the shaft 1 to the inner circumferential surface 1f of the inner tube 1B. By following the guide wire, it is inserted into the patient's body. The balloon catheter 10 is inserted, as necessary, through an insertion tube member inserted into the body, such as an endoscope (not shown).
At this time, the dilation fluid is not introduced into the balloon 2 of the balloon catheter 10, and the balloon 2 is in the initial state. Therefore, the distal end portion of the balloon catheter 10 has a diameter as small as the outer diameter of the shaft 1 and, like the shaft 1, can be smoothly inserted into the patient's body.

When the balloon 2 of the balloon catheter 10 is inserted at the site where the lumen is to be expanded, the operator connects a fluid supply device (not shown, hereinafter the same) to the proximal opening 1 d of the shaft 1.
The operator operates the fluid supply device to introduce the expansion fluid into the internal flow path P.
The expanding fluid introduced into the internal flow path P flows into the internal space S of the balloon 2 from the distal end opening 1c at the distal end of the outer tube 1A. As the expansion fluid flows into the internal space S, the balloon 2 expands. As the balloon 2 is expanded, the diameter-increased portion 2B is expanded in diameter, and the inner surface of the lumen in contact with the diameter-increased portion 2B is pushed apart.
When the pressure of the expansion fluid reaches a predetermined pressure, the operator stops the supply and pressurization of the expansion fluid. As a result, the balloon 2 is expanded to a certain expanded state, and the lumen is expanded to a predetermined shape. Above, the treatment of the expansion of the lumen by balloon catheter 10 is completed.

Here, the shape of the diameter-expanded state of the balloon 2 will be described using an example in which the balloon 2 is expanded in free space.
The balloon 2 expands into the naturally deployed state as shown in FIG. 1 when the expansion fluid corresponding to the volume in the naturally deployed state is introduced. Tension (stress) is not generated in the balloon 2 in the natural expanded state, the balloon 2 will generally cylindrical shape of the outer diameter D _0.
When the expansion fluid is further supplied into the internal space S, the internal pressure of the balloon 2 rises, and the balloon 2 is expanded. The balloon 2 differs in material depending on the part, so the expansion rate differs depending on the elongation property and thickness of the material of each part.
The elongation properties of the material of each part can be represented by the magnitude of 100% modulus. If the thickness is the same, the smaller the 100% modulus, the easier it is to stretch. In the case where the 100% modulus is the same, the thinner the portion, the greater the stress and thus the easier it is to stretch.
That is, in the balloon 2, the expansion rate becomes relatively large at the portion of the first end 2D close to the joint 2e and the portion of the second end 2F close to the joint 2f. As a result, as shown in FIG. 3, the portion of the first end 2D near the joint 2e and the portion of the second end 2F near the joint 2f have outer diameters D _2B and D _2D respectively (where D _2B > D ₀ , D _2D > D ₀ ). On the other hand, the outer diameter of the portion excluding both ends of the central portion 2E is D _2E smaller than the outer diameters D _2B and D _2D (where D ₀ <D _2E <D _2B , D ₀ <D _2E < Stay in D ₂ D).
In the present embodiment, since the first end 2D and the second end 2F are formed of the same material and have the same shape in the natural state, D _2B = D _2D .
The tip 2g (base end 2i) of the central portion 2E receives tensile stress including a component directed radially outward from the first end 2D (second end 2F) via the joint 2e (2f). , D _2E and D _2B (D _2D ) expand to an outer diameter.

Thus, in the diameter-expanded state of the balloon 2, the distal end side of the central portion 2E closer to the joint portion 2e than the distal end portion 2g and the proximal end side of the central end 2e near the joint portion 2f Then, dome-shaped bulged portions 2j and 2k of the maximum outer diameter D _2B and D _2D are formed. An intermediate portion 2h of the central portion 2E sandwiched between the bulging portions 2j and 2k becomes a cylindrical portion with an outer diameter D _2E .
Therefore, the outer diameter of the enlarged diameter portion 2B of the balloon 2 has a so-called dog bone shape.
Bulging portions 2j, 2k outer diameter D _2B, D _2D can be appropriately sized to positional deviation in the axial direction of the balloon 2 at the time of insertion into the lumen can be suppressed. For example, it may be 103% or more and 120% or less of the outer diameter D _2E of the intermediate portion 2 h.
The positional deviation of the balloon 2 may be suppressed to such an extent that the balloon 2 does not come out of the narrowed portion of the lumen at the time of diameter expansion.

As mentioned above, although the shape of the diameter-expanded state in free space was demonstrated, if the reaction force from the inner wall of a lumen is equally distributed in the lumen which has a constriction part, only the absolute value of the outer diameter will differ. The dogbone shape is similar.
Therefore, when the expansion of the balloon 2 is started in the lumen, the outer diameter of the balloon 2 becomes constant corresponding to the natural deployed state, and the outer diameters of both ends of the balloon 2 It will increase relatively. Therefore, since the bulging portions 2j and 2k at both ends of the balloon 2 bite relatively larger in the inner wall of the lumen than the middle portion 2h, both ends of the balloon 2 are more firmly locked than the central portion 2E. It is expanded in the state. As a result, in the balloon 2, since the bulging portions 2 j and 2 k at both ends resist the movement in the axial direction during expansion, the movement of the balloon 2 in the axial direction is suppressed.

For example, consider the case where the balloon is not formed with bulges at both ends, and the central part of the central part has a maximum outer diameter and the diameter is reduced toward both ends so that the central part is thickened and expanded. In this case, since the constriction portion abuts on the top of the convex surface at the center of the central portion, an unstable contact state is formed. For example, when an external force acts on the balloon in the axial direction, or when the smallest portion of the narrowed portion and the largest outer diameter portion of the central portion are axially shifted, the narrowed portion is in a stable contact state. Try to move relative to the end of the direction. Thus, the balloon having no bulging portion at both ends may be pushed out in the axial direction during diameter expansion.

Better bulges 2j and 2k are formed when the axial length of the first end 2D and the second end 2F is 15% or more and 25% or less of the axial length of the enlarged diameter portion 2B. Be done.
When the axial length of the first end 2D and the second end 2F is less than 15% of the axial length of the enlarged diameter portion 2B, the axial length of the bulges 2j and 2k is Since it becomes short, there is a possibility that the control effect of the movement of the direction of an axis by bulging part 2j and 2k may fall.
When the axial length of the first end 2D and the second end 2F exceeds 25% of the axial length of the enlarged diameter portion 2B, the diameter of the intermediate portion is smaller than that of the bulges 2j and 2k. Since the length of the portion 2h becomes short, the contact amount between the lumen and the central portion 2E becomes too small, so that the effect of suppressing the axial movement by the bulging portions 2j and 2k may be reduced.

Here, the diameter expansion state of the balloon 200 of the comparative example shown to FIG. 4, 5 is demonstrated.
FIG. 4 is a schematic front view of the balloon catheter of the comparative example in a naturally deployed state.
FIG. 5 is a schematic front view of the balloon catheter of the comparative example in the expanded state.

As the external shape of the natural expansion state is shown in FIG. 4, in the balloon 200 of the comparative example, the shape of the natural expansion state is the first fixing portion 2A of this embodiment and the enlarged diameter portion from the distal end side to the proximal end side. A second fixing portion 200A, an enlarged diameter portion 200B, and a second fixing portion 200C, which are similar to the second fixing portion 2C, are provided. In the enlarged diameter portion 200B, a diameter transition portion 200a having the same outer shape as the diameter transition portion 2a of the present embodiment, a constant diameter portion 2b, a central portion 2E, and a constant diameter portion 2c from the distal end side to the proximal end side. And a diameter transition portion 200c having an outer shape similar to that of the diameter transition portion 2d. The constant diameter portion 2b of the present embodiment, the central portion 2E, and like the constant diameter portion 2c, the outer diameter of the central portion 200b in the natural development state is _{D 0.}
However, since the balloon 200 is formed of one type of material, the 100% modulus of the material of the enlarged diameter portion 200B is constant regardless of the part.
The balloon 200 is manufactured, for example, by blow molding a parison tube made of a single material using a mold for molding the balloon 2 of the present embodiment. The thickness distribution of the balloon 200 is similar to the thickness distribution of the balloon 2.

When the diameter of the balloon 200 of the comparative example is expanded from the natural deployed state, as shown in FIG. 5, in the free space, substantially uniform expansion in the radial direction in which the outer diameter increases as a whole occurs. For this reason, the balloon 200 in the expanded state is expanded in a substantially cylindrical shape having a constant outer diameter D _200B (where D _200B > D ₀ ) over substantially the entire length of the central portion 200b.
Such a substantially uniform diameter expansion condition occurs when the lumen does not have a constriction. In this case, since the amount of biting into the lumen of the balloon 200 becomes substantially constant over the entire length, sliding movement of the balloon 200 in the axial direction is likely to occur.

The balloon 200 of the comparative example, which is inflated as shown in FIG. 5 in free space, is a portion where the balloon located at the non-narrowed portion is the narrow portion when inflated in the lumen having the narrowed portion and the non-narrowed portion. There is less expansion resistance than the part of the balloon located at. For this reason, in a lumen having a constricted part and a non-constricted part, inflation starts from a balloon located in the non-constricted part. For this reason, inflation is started from either the front or back end of the balloon unless the stenosis is accurately located at the center of the balloon, so the balloon tends to move due to the reaction force from the stenosis at the balloon being inflated. is there. Also, even if the constriction is located exactly at the center of the balloon, depending on the shape of the constriction, the balloon may be subjected to a drag to move.
As described above, since the balloon 200 of the comparative example is easily moved due to the resistance of the constriction part during the uneven expansion, it may be separated from the constriction part in the expansion process. Even if the shaft is not completely removed, the balloon may be locked by the uneven bulging portions at both ends, so that the shaft may be easily removed from the narrowed portion only by lightly pushing and pulling the shaft.

In the balloon 200 of the comparative example, in order to form a dog bone shape in a diameter-expanded state in free space, the wall thickness of both ends of the central portion 200b or the diameter transition portions 200a and 200c is compared to the middle portion of the central portion 200b. It is also conceivable to make it thinner. However, in this case, since the breaking strength is reduced at the portion where the thickness is thin, the pressure resistance of the balloon is reduced.

Conventionally, it has been proposed to make the shape of the balloon in a naturally deployed state into a dog bone shape. However, in this case, since the shape of the balloon in a naturally-expanded state becomes a complicated three-dimensional shape, when the balloon is contracted, it can not be folded into a plurality of flat wings. Thereby, even if it winds around a shaft in the state which folded the balloon, a part will rise and an uneven part will arise.
On the other hand, since the balloon 2 of the present embodiment is substantially cylindrical in a naturally deployed state, it can be folded into a plurality of flat plates if the folding position is appropriately set when the balloon 2 is contracted. It is. The outer diameter when wound around the shaft 1 is substantially uniform. Therefore, the balloon can be smoothly inserted into and removed from the lumen. Similarly, insertion and removal to a tube member such as an endoscope which is inserted to guide the balloon 2 can be smoothly performed.

After the expansion of the balloon 2 is completed, the operator performs the removal operation of the balloon catheter 10.
The operator operates the fluid supply device to decompress the expansion fluid and aspirate the expansion fluid from the proximal opening 1d.
The expansion fluid in the internal space S is gradually discharged into the internal flow path P from the distal end opening 1 c. The balloon 2 is contracted according to the discharge amount of the expansion fluid. The balloon 2 is in the same state as being wound around the shaft 1 as in the initial state.
When the balloon 2 is contracted, the operator retracts the balloon catheter 10 along the guide wire or with the guide wire, and withdraws from the lumen. At this time, since the outer diameter of the reduced balloon 2 is substantially the same as the outer diameter of the shaft 1, smooth removal is possible.

As described above, according to the balloon catheter 10 provided with the balloon 2 of the present embodiment, it is possible to suppress axial positional deviation at the time of attachment to the lumen without reducing the pressure resistance and the insertion / extraction performance of the balloon 2. . For this reason, at the time of diameter expansion, the balloon 2 is disposed at the narrowing portion without being separated from the narrowing portion of the lumen.

In the description of the above embodiment, the shaft has an internal flow passage used for the circulation of the expansion fluid, and a through hole used for other applications such as insertion of a guide wire and circulation of a chemical solution, for example. I explained in the example. However, when it is not necessary to insert a guide wire or to distribute a drug solution, the shaft may be formed with only the internal flow path. In this case, the inner tube 1B may be replaced by a tube whose tip is sealed or a solid rod-like member. Alternatively, the shaft may be configured such that the distal end side opening is provided on the side surface of the single-lumen tube whose distal end is sealed.

Hereinafter, Examples 1 to 8 of the balloon catheter 10 of the above embodiment will be described together with Comparative Examples 1 to 4.
The structures of the balloons in Examples 1 to 8 and Comparative Examples 1 to 4 and the evaluation results are shown in the following Table 1. In the following [Table 1], the material of the balloon and the length ratio (%) of each part of the balloon are shown among the configurations of the balloon. The ratio of the axial length of each part to the axial length of the enlarged diameter part is displayed as a percentage of the length ratio of the balloon.
Specific material names of the materials in the following [Table 1] are shown in the following [Table 2]. In the resin A, the resin B, the resin C, the resin D, the resin E, and the resin F, the value of 100% modulus increases in this order.

Example 1
As shown in Table 1, in the balloon 2 in Example 1, the resin C was used for the first end 2D and the second end 2F, and the resin F was used for the central portion 2E.
As shown in [Table 2], Resin C is PEBAX (registered trademark) 6333 (trade name; manufactured by Arkema). The 100% modulus and tensile strength at break of resin C are 17 MPa and 55 MPa, respectively.
Resin F is Grilamid (registered trademark) L25 (trade name; manufactured by Emskemy). The 100% modulus and tensile strength at break of the resin F are 28 MPa and 71 MPa, respectively. Therefore, the tensile breaking strengths of the first end 2D and the second end 2F are 77% of the tensile breaking strength of the central portion 2E.
In the balloon 2 in the present embodiment, the axial lengths of the enlarged diameter portion 2B, the first end 2D, the central portion 2E, and the second end 2F are 100 mm, 25 mm (length ratio 25%), 50 mm, respectively. (Length ratio 50%), 25 mm (Length ratio 25%). The axial lengths of the diameter transition portion 2a, the constant diameter portion 2b, the constant diameter portion 2c, and the diameter transition portion 2d are L _2a = L _2d = 12 (mm) and L 2 _b = L _2c = 13 (mm). The
The outer diameter D ₀ of the balloon 2 in the natural deployed state in this example was 16.5 mm. The thickness of each of the central portion 2E and the constant diameter portions 2b and 2c was 0.04 mm. The thickness was determined as half of the thickness of two sheets measured by bending the balloon 2.
The balloon 2 of Example 1 was made by blow molding, forming a parison tube from the above-mentioned materials.
The balloon 2 of Example 1 was fixed by welding to a shaft 1 having an outer diameter of the inner tube 1B of 1.6 mm and an outer diameter of the outer tube 1A of 2.0 mm.
When the balloon 2 was subjected to a known folding process and in an initial state, the outer diameter of the balloon 2 was substantially uniform in the axial direction, and was about 2.7 mm.
Above, the balloon catheter 10 of Example 1 was formed.

Example 2
As shown in [Table 1], in the configuration of the balloon 2 in Example 2, the length ratio of the first end 2D, the center 2E, and the second end 2F is 15%, 70%, and 15%, respectively. The same as in Example 1 except for the above. In this embodiment, the axial lengths of the diameter transition portion 2a, the constant diameter portion 2b, the constant diameter portion 2c, and the diameter transition portion 2d are L _2a = L _2d = 12 (mm), L _2b = L _2c = 3. (Mm) was taken.

[Examples 3 and 4]
As shown in Table 1, the configuration of the balloon 2 in Example 3 was the same as Example 1 except that resin E was used as the material of the central portion 2E. The balloon 2 in Example 4 was the same as Example 2 except that resin E was used as the material of the central portion 2E.
As shown in [Table 2], resin E is PEBAX (registered trademark) 7233 (trade name; manufactured by Arkema). The 100% modulus and tensile strength at break of resin E are 22 MPa and 67 MPa, respectively. For this reason, the tensile breaking strength of the first end 2D and the second end 2F is 82% of the tensile breaking strength of the central portion 2E.

[Examples 5, 6]
As shown in [Table 1], the configuration of the balloon 2 in Example 5 was the same as Example 3 except that resin D was used as the material of the first end 2D and the second end 2F. . The configuration of the balloon 2 in Example 6 was the same as that of Example 4 except that the resin D was used as the material of the first end 2D and the second end 2F.
As shown in [Table 2], resin D is PEBAX (registered trademark) 7033 (trade name; manufactured by Arkema). The 100% modulus and tensile strength at break of resin D are 21 MPa and 59 MPa, respectively. Therefore, the tensile breaking strength of the first end 2D and the second end 2F is 88% of the tensile breaking strength of the central portion 2E.

[Example 7]
As shown in [Table 1], in the configuration of the balloon 2 in Example 7, the resin B was used as the material of the first end 2D and the second end 2F, the first end 2D, and the central part Except for the fact that the length ratio of 2E and the second end 2F was set to 20%, 60%, and 20%, respectively, it was assumed that it was the same as Example 1. In this embodiment, the axial lengths of the diameter transition portion 2a, the constant diameter portion 2b, the constant diameter portion 2c, and the diameter transition portion 2d are L _2a = L _2d = 12 (mm), L _2b = L _2c = 8 (Mm) was taken.
As shown in Table 2, the resin B is PEBAX (registered trademark) 5533 (trade name; manufactured by Arkema). The 100% modulus and tensile strength at break of the resin B are 16 MPa and 44 MPa, respectively. Therefore, the tensile breaking strength of the first end 2D and the second end 2F is 62% of the tensile breaking strength of the central portion 2E.

[Example 8]
As shown in [Table 1], the configuration of the balloon 2 in Example 8 is the same as Example 7 except that resin A was used as the material of the first end 2D and the second end 2F. .
As shown in [Table 2], Resin A is PEBAX (registered trademark) 4033 (trade name; manufactured by Arkema). The 100% modulus and tensile strength at break of the resin A are 13 MPa and 36 MPa, respectively. Therefore, the tensile breaking strength of the first end 2D and the second end 2F is 51% of the tensile breaking strength of the central portion 2E.

Comparative Example 1
As shown in [Table 1], in the configuration of the balloon in Comparative Example 1, resin C was used as the material of the central portion, and resin F was used as the material of the first end and the second end. , The same as Example 7.
Therefore, the 100% modulus at the first end and the second end is 11 MPa larger than the 100% modulus at the central portion.
The tensile breaking strength of the first end and the second end was 129% of the tensile breaking strength of the central portion.

Comparative Example 2
As shown in Table 1, the configuration of the balloon in Comparative Example 2 was the same as Comparative Example 1 except that resin D was used as the material of the central portion.
Therefore, the 100% modulus at the first end and the second end was 7 MPa larger than the 100% modulus at the central portion.
The tensile breaking strength of the first end and the second end was 120% of the tensile breaking strength of the central part.

[Comparative Examples 3 and 4]
As shown in [Table 1], in the configuration of the balloon in Comparative Example 3, the resin E was used for the entire enlarged diameter portion, and the length ratio of the first end, the center, and the second end was Except for 13%, 74%, and 13%, respectively, it was considered to be the same as Example 1. In this comparative example, the axial length of the diameter transition portion on the distal end side and the constant diameter portion is 12 mm and 1 mm, respectively, and the axial length of the diameter transition portion on the base end side is 12 mm and 1 mm, respectively. It was 1 mm and 12 mm.
As shown in [Table 1], the configuration of the balloon in Comparative Example 4 was the same as Comparative Example 3 except that the resin C was used for the entire enlarged diameter portion.

[Evaluation]
As shown in [Table 1], for the evaluation of each example and each comparative example, evaluation of positional deviation, pressure resistance strength, and insertion / removal property was performed.
FIG. 6 is a schematic cross-sectional view showing the shape of a narrowed portion used for evaluation of positional deviation.

The positional deviation was evaluated using an evaluation jig 100 as shown in FIG.
The evaluation jig 100 was formed in a shape that simulates a narrow portion of a lumen whose internal diameter of the non-constriction portion is 20 mm. The evaluation jig 100 is provided with a through hole 101 in which a taper portion 101a, a circular hole portion 101b, and a taper portion 101c are coaxially formed in this order in a block material made of silicone.
The circular hole portion 101 b is a shape portion that simulates a narrowed portion. The circular hole portion 101 b had a diameter α of 5 mm and a length β of 10 mm. The tapered portion 101a (101c) is expanded in diameter from the distal end (proximal end) of the circular hole portion 101b toward the distal end (proximal end) to the inner diameter of the non-constricted portion of the lumen. The taper angle θ of the tapered portions 101a and 101c was 25 °.

In the evaluation of the positional deviation, the balloon of the balloon catheter of each example and each comparative example was inserted into the circular hole portion 101b of the evaluation jig 100, and the expansion fluid consisting of warm water was introduced into the internal space of the balloon. The balloon was thus expanded. The pressure of the expansion fluid was set to a pressure at which the outer diameter of the central portion of the enlarged diameter portion in the free space became 18 mm. The pressure varies depending on the material of the central portion of the enlarged diameter portion, but was 2026.5 hPa to 4053.0 hPa in Examples 1 to 8 and 2026.5 hPa to 4053.0 hPa in Comparative Examples 1 to 4.
Thereby, each balloon was able to expand the hole portion 101 b.
In this state, the shaft was pushed and pulled in the axial direction. At this time, it was evaluated whether the balloon was removed from the stenosis. If the balloon did not come off the stenosis, "good" (described as "good" in [Table 1]), if the balloon came off the stenosis, "poor" (no good, in [Table 1] Described as “×”).

Evaluation of compressive strength was performed depending on whether or not the balloon was ruptured by applying an internal pressure of 7092.75 hPa (7 atm).
When the compressive strength is 7092.75 hPa (7 atm) or more, "good" (good, described as "○" in [Table 1]), and when the compressive strength is less than 7092.75 hPa (7 atm), "defect" (no good) , [Table 1] described as "x").

The evaluation of the releasability was performed by measuring the amount of force when the balloon catheter in a deflated state was inserted into and removed from the evaluation jig 100.
When the insertion capacity is 7N or less and the extraction capacity is 20N or less, "Good" (described as "o" in [Table 1]), the insertion capacity exceeds 7N, or the extraction capacity is When it exceeded 20 N, it was evaluated as "defect" (denoted as "good" and described as "x" in [Table 1]).

[Evaluation results]
As shown in [Table 1], in Examples 1 to 6, all of the evaluation results of “displacement”, “pressure resistance strength”, and “removability” were “good (○)”, and therefore, as a comprehensive evaluation , "Very good" (very good, described in Table 1 as "◎") was evaluated.
In Examples 7 and 8, the evaluation results of "displacement" and "removability" were "good (o)". Although the evaluation result of "pressure resistance strength" was "good (o)", it did not clear with a sufficient margin. Therefore, the overall evaluation was evaluated as "good" (good, described as "○" in [Table 1]).

On the other hand, in Comparative Examples 1 to 3, the evaluation result of “pressure resistance strength” was “good (○)”, but “positional misalignment” and “removability” are “defect (x)”. Therefore, as a comprehensive evaluation, it was evaluated as "defective" (No good, described as "x" in [Table 1]).
In Comparative Examples 1 and 2, the 100% modulus of the material of the first end portion and the second end portion was 100% of the material of the central portion in the evaluation results of “misalignment” being “defective (×)”. Since it is larger than the% modulus, it is considered that the outer diameter of the central portion is maximized at the time of diameter expansion and the bulging portion is not formed at both ends.
It is considered that the reason why the “displacement” becomes defective in Comparative Example 3 is that the diameter-increased portion of Comparative Example 3 is formed of a single material. That is, when the balloon starts to inflate from the non-constriction part, the expansion of both ends becomes uneven, and as a result of being expanded in one direction by the drag of the constriction part, it is dislodged when it is pushed and pulled to one side. Is considered to be
The reason why the “removability” is “defective (x)” in Comparative Examples 1 to 3 is considered to be that the material at both ends is formed of the resins E and F having a relatively large modulus of 100%. The 100% modulus of the material also affects the removability, and it is considered that the removability is inferior when the material having the large 100% modulus is at both ends (in the state where the balloon is folded).
On the other hand, Comparative Example 4 was evaluated as "good (o)" for "pressure resistance strength" and "removability" but because "displacement" was "defect (x)", "poor" as a comprehensive evaluation. It was evaluated as (no good, described as "x" in [Table 1]).
In Comparative Example 4, the reason why the “displacement” is “defect (x)” is considered to be the same reason as in Comparative Example 3.
The reason why the “removability” was “good (○)” in Comparative Example 4 is considered to be that the 100% modulus of the material at both ends of the Comparative Example is made of the resin C smaller than the resins E and F. .

As described above, in Comparative Examples 1 to 4 at least the evaluation of "displacement" was poor, while in Examples 1 to 8, the evaluation results of "displacement" and "insertability" were all obtained. It is understood that was good.

Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples. Additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, and is limited only by the appended claims.

1 Shaft 1A Outer tube 1B Inner tube 1a, 1e Outer peripheral surface (outer peripheral part)
1c tip side opening 1d base end side opening 2 balloon 2A first fixed part 2B enlarged diameter part 2C second fixed part 2D first end 2E central part 2F second end 2a, 2d diameter transition part 2b, 2c fixed Diameter 2e, 2f Junction 10 Balloon catheter O Central axis P Internal channel S Internal space

Claims (5)

1. A shaft for passing the expansion fluid through the distal opening;
   A first fixing portion fixed to the distal end side of the distal end side opening at the outer peripheral portion of the shaft; and a second fixing portion fixed to the proximal end side of the distal end side opening at the outer peripheral portion of the shaft A balloon having an enlarged diameter portion formed between the first fixed portion and the second fixed portion and expanded by the expansion fluid supplied from the distal end side opening portion;
   Equipped with
   The enlarged diameter portion is configured such that a first end, a central portion, and a second end are adjacent to each other in this order from the first fixed portion to the second fixed portion.
   The 100% modulus of the first end and the second end material is lower than the 100% modulus of the central portion material,
   Balloon catheter.
2. The length in the longitudinal direction of the shaft of the first end and the second end is 15% or more and 25% or less of the length in the longitudinal direction of the shaft of the enlarged diameter portion.
   The balloon catheter according to claim 1.
3. The breaking strength of the material of the first end and the second end is 80% or more of the breaking strength of the material of the central portion,
   The balloon catheter according to claim 1.
4. In the natural expansion state of the enlarged diameter portion, in which the enlarged diameter portion is expanded without generating stress,
   The maximum outer diameters of the first end, the central portion, and the second end are equal to one another,
   The balloon catheter according to claim 1.
5. In the natural expansion state of the enlarged diameter portion, in which the enlarged diameter portion is expanded without generating stress,
   The first end portion and the second end portion each have a diameter transition portion whose outer diameter increases in a direction toward the central portion, and a constant diameter portion extending at a constant diameter from a portion which becomes the maximum outer diameter of the diameter transition portion Have and
   The outer shape of the diameter transition portion is a bowl shape,
   The balloon catheter according to claim 1.

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