HK1070843A - Balloon catheter - Google Patents

Description

Balloon catheter

The invention is a divisional application of Chinese patent application No. 00807347.3

Technical Field

The present invention relates to balloon catheters. The balloon catheter is used for treatment or operation for expanding a lesion site such as a stenosis portion or an occlusion portion of a body passage, and more specifically, is used in Angioplasty (PTA: peripheral angious transfumin Angioplasty, PTCA: peripheral anous transfumin Coronary Angioplasty) such as peripheral Angioplasty, Coronary Angioplasty, and valvuloplasty.

Background

Balloon catheters are used primarily for the treatment of stenotic or occluded body passages to form body passages. In general, a balloon catheter has a structure in which a balloon communicating with an expansion lumen to which a pressure fluid is supplied is provided at a distal end portion of a tubular catheter shaft having a plurality of lumens inside, and ports communicating with the respective lumens are provided at a proximal end portion. In a normal state, the balloon is folded onto the catheter shaft. The PTCA operation using the balloon catheter was performed in the following manner. A guide catheter is inserted from a puncture site of a femoral artery, passed through the aorta, and the tip thereof is placed at the entrance of a coronary artery. Next, the guide wire passed through the guide wire lumen is advanced through the stenosed portion of the coronary artery, the balloon is inserted along the guide wire and fitted into the stenosed portion, and a pressure fluid is supplied to the balloon through the inflation lumen using a syringe or the like to inflate the balloon, thereby performing an expansion treatment on the stenosed portion. After the stricture portion is sufficiently expanded, the balloon is deflated and contracted, folded and pulled out of the body, thereby completing PTCA. In the present operation example, the expansion of a coronary artery stenosis by PTCA is described, but the balloon catheter can be used for other vascular lumens or body lumens.

A balloon catheter is inserted into a body passage to be treated, and an internal pressure is introduced into a treatment site to perform an expansion treatment. Therefore, the following characteristics are required. That is, when the pressure required for expansion is introduced, the balloon should have sufficient strength so as not to break and the required expansion dimension should be safely controlled. In many cases, particularly in the treatment of a vascular system, it is necessary to insert a catheter from an insertion port along a blood vessel to a lesion or a predetermined site, and therefore, the operability of the catheter is also important.

Since the catheter is usually formed of a cylindrical elongated member, and after insertion from the insertion port, the catheter must be manipulated outside the body to pass through a curved portion or a narrowed portion in the body, a force acting from outside the catheter body must be efficiently transmitted to the distal end portion, and flexibility capable of coping with the curved portion is required. In addition, generally, a guide wire is passed through the inside, and in order to ensure transmission of force and to move the catheter smoothly, it is also an important characteristic that frictional resistance between the catheter and the guide wire is small. In order to obtain such operability, the following characteristics are generally required for the structure of the balloon catheter. (1) The distal (distal) portion has a certain flexibility to allow good compliance with the tortuous path in the body. (2) The near (proximal) portion has a certain strength so that the force is transmitted to the front end well. (3) The tubular member having the wire passing therethrough has a small frictional resistance, a low frictional property and a high sliding property. To satisfy these characteristics, many catheters are made of polyethylene, high-strength polyamide, or high-strength polyamide elastomer.

An important characteristic associated with flexibility is the flexibility of the balloon portion at the distal end of the catheter and its vicinity. This portion is flexible, and is often inserted into a bent portion, and is in sliding contact with the most flexible portion of the lead inserted inside, and therefore, continuity is required for the flexibility. Since when the catheter is disposed at the bent portion, if the flexibility thereof is discontinuous, the bending of the catheter generates discontinuity, the resistance of the wire at the portion is significantly increased, resulting in a reduction in operability.

In general, a fixed portion of a tubular member through which a balloon and a guide wire are passed is present as a distal end portion "tip" at a distal end of a catheter, and if the tip portion is hard, the difference in flexibility from the guide wire coming out from the tip (tip) is large, and the guide wire is easily bent at the position, which is the most factor of deterioration in operability.

In addition, in the case where a calcified lesion is formed, when a guide wire is passed through such a portion and a balloon catheter is tried to be passed along the guide wire, if the tip portion is hard, the tip portion is often caught in the calcified lesion and cannot pass through the lesion.

In recent years, in the blood vessel expansion treatment, a metallic indwelling stent called a stent is often used, and in order to perform post-expansion (post-dilation) after expansion of the stent (stent), when restenosis occurs in the stent fixing mold or when stenosis occurs on the distal side of the stent, it is necessary to pass a balloon catheter through the stent fixing mold. In this case, if the tip portion is as hard as the calcified lesion, the balloon catheter is caught by the metal stent and cannot pass through the stent.

As mentioned above, it is important to make the tip portion of the balloon catheter, particularly the tip portion, soft to reduce the difference in hardness from the rest of the catheter. As a method of processing the tip portion, a method of joining and fixing a tubular member through a guide wire to a balloon by bonding or welding may be used. The tip portion tends to be hardened due to the presence of the adhesive layer by the method of adhesion, and the diameter can be easily reduced by hot working at the time of welding or after welding without the presence of the adhesive layer by the method of welding. Therefore, the welding method is advantageous in terms of flexibility.

However, in the conventional catheter, a tubular member through which a wire passes (a tubular member for passing a wire) is often made of a polyolefin material, i.e., polyethylene, and particularly, low-friction high-density polyethylene is often used. High-density polyethylene is a good material as a low-friction material, but is poor in weldability and bondability to other materials, and cannot be welded except for polyolefin materials. Therefore, bonding to other materials can be achieved only by adhesion. In the balloon made of a polyolefin material, the thickness of the balloon cannot be reduced as a welding margin required for crosslinking the material, and as a result, the tip portion cannot be made soft even by welding. In addition, low-friction high-density polyethylene has poor flexibility. On the other hand, low density polyethylene, which is relatively soft, is hardly used because its friction and sliding properties are remarkably reduced as the flexibility increases. When a polyethylene single-layer tubular member is used as a tubular member for passing a lead wire, it is not easy to provide sufficient flexibility to the tip portion.

In addition, there is a commercially available balloon catheter in which a tubular member is formed of a double tube, that is, a guide wire is passed through the inside of the tubular member using polyethylene and the outside using polyamide. The balloon is made of polyamide having the same properties as the tubular member. However, since polyamide generally has a higher modulus of elasticity than polyethylene, the tip portion cannot have sufficient flexibility.

Further, there is a commercially available balloon catheter composed of a balloon made of a polyamide elastomer and a tubular member for passing a lead made of a polyamide elastomer having a higher hardness and a higher melting point than those of the balloon. The balloon is welded to the tubular member. However, since the tubular member for passing the lead wire is provided with a material harder than that of the balloon, the tip portion does not have sufficient flexibility.

Accordingly, an object of the invention 1 is to provide a balloon catheter which has an improved distal most tip portion, i.e., a tip portion, and which is excellent in flexibility and operability.

In addition, the balloon has various characteristics in addition to the above characteristics. A PTCA balloon catheter is exemplified. When a calcified portion or a hard narrow portion where a stent is placed is expanded, high compressive strength is required, but a high compressive strength material generally lacks flexibility. On the other hand, in order to reach the stenosed portion through a curved stenosed blood vessel, it is necessary to have high flexibility and thin wall property of a balloon. In addition, the flexibility of the balloon is greatly related to the performance (passing performance or passing performance) when the balloon is passed through the stenosis portion or the passing performance, and particularly, when the balloon is reused, if the flexibility of the balloon cannot be maintained, the passing performance is low.

In addition, a further desired characteristic is that when a hard stricture is dilated, even if high pressure is applied to the balloon, the vessel wall is not damaged by excessive dilation. That is, the limitation of the radial elongation (expansion and contraction characteristics) of the balloon against the expansion pressure is very important. The expansion and contraction characteristics can be classified into the following three types depending on their responsiveness to expansion pressure. That is, (1) the most limited expansion/contraction characteristic as the expansion/contraction ratio is that the balloon diameter change ratio is 2% to 7% (no expansion/contraction) when the expansion pressure is changed within the range of 6atn to 12 atm. (2) For the same expansion pressure change, the rate of change of the balloon diameter is 7% -16% (half-expansion). (3) For the same expansion pressure change, the change rate of the balloon diameter is 16-40% (expansion)

To prevent excessive expansion of the vessel wall when a hard stenosis is dilated with high pressure, the balloon should have a telescoping character of at least half-telescoping, preferably no telescoping. Although a balloon having flexibility, high compressive strength and appropriate elongation (expansion and contraction characteristics) is most preferable, these characteristics are contrary to each other in view of the physical properties of the balloon material. In order to balance these opposite characteristics well, the following polymer blend materials have been used in the prior art.

As a conventional technique for using a polymer blend material for balloons, there is a "balloon for medical devices made of a thermoplastic elastomer" described in Japanese patent application laid-open No. 9-506008. This publication discloses a balloon using a mixture of an engineering thermoplastic elastomer and a polymer material for a non-flexible structure, and discloses a layered balloon using a polymer layer for a non-flexible structure and a soft and abrasion-resistant thermoplastic elastomer layer.

In addition, in Japanese patent application laid-open No. 10-506562 ("expanded balloon containing polyether ester amide based copolymer"), the disclosed expanded balloon is provided with a single polymer layer (the single polymer layer contains polyether ester amide based copolymer and polyamide such as nylon), and when the polymer layer contains polyether amide, the polyether amide has ester bond.

Further, Japanese patent application laid-open No. 8-127677 (a polymer mixture for producing medical devices provided with balloons and catheters for dilating catheters) discloses a polymer mixture for medical use. The medical polymer composite material contains a 1 st polymer component and a 2 nd polymer component. The 1 st polymer component is selected from the group consisting of polyesters and polyamides. The 2 nd polymer component is selected from polyolefin, ethylene copolymer, polyester block copolymer and polyamide block copolymer, and has Shore hardness less than D75.

The above prior arts all use a mixture of a soft elastomer and a non-elastomer having high strength. However, in these prior arts, the flexibility and strength of the balloon are greatly changed depending on the blending ratio of the two components, and it is very difficult to optimize the blending ratio. Further, the laminated balloon described in the above-mentioned Japanese patent application laid-open No. 9-506008 is complicated in the extrusion molding step for producing a tubular blank as a balloon material, and is expensive in production cost, and there is a possibility that delamination may occur between layers of the produced laminated balloon.

In view of the above problems, it is an object of the invention 2 to provide a balloon catheter using a balloon made of a polymer hybrid material having sufficient compressive strength, flexibility and appropriate expansion and contraction characteristics.

In addition, the dilation treatment of a lesion is usually performed not only once but several times. This is because, when the balloon is pulled out of the body after the expansion treatment and the stricture portion is confirmed to be not completely expanded by imaging, the balloon is repeatedly extended to the affected part and expanded until the stricture portion is completely expanded.

When the balloon catheter is provided as a product, the balloon is in a state of being contracted, having the smallest outer diameter, and folded around the guide wire passage tubular member. Therefore, in the initial use, the balloon is passed through the stenosis without difficulty, and then the internal pressure of the balloon is increased to expand the balloon. However, when the balloon is pulled out of the body, even if the balloon is decompressed and contracted, the balloon cannot return to the original folded state, and the balloon compressed flat is expanded horizontally in the radial direction, and both wings are formed. The length of the wings is larger than the outer diameter of the folded balloon and also larger than the nominal diameter of the balloon, so that the expansion treatment by the balloon is difficult to perform again. That is, due to the wings, the tapered portions of the divided balloons hit the narrowed portion of the lumen of the blood vessel and cannot travel any further. This is because the distal tapered portion forms a steep step when the blade is formed. In particular, when a hard lesion part where a calcification or a stent is to be placed is calcified and a balloon having a wing is passed through, the operator feels a large resistance, and if the balloon is advanced hard, the stent may be pressed against the distal side of the blood vessel, causing positional displacement of the stent, which is dangerous.

The same problem as described above is described in detail in japanese patent No. 2671961, which discloses a balloon catheter that can return to a folded state without having wings on the balloon. The balloon catheter is provided with a balloon having longitudinal grooves in the longitudinal direction, and the longitudinal grooves disappear when the balloon is expanded, and the balloon returns to a folded state along the longitudinal grooves when the balloon is contracted.

However, in the balloon disclosed in the above publication, if a high internal pressure not less than a certain level is not applied, the longitudinal grooves remain during expansion, and the outer shape of the cross section thereof cannot be circular. If the cross section is not circular in shape, the stricture portion cannot be uniformly expanded all around, and there is a high risk of restenosis occurring in a short period of time.

In view of the above problems, the object of the invention 3 is to provide a balloon catheter equipped with a balloon which can greatly reduce high resistance at the time of pushing due to the influence of wings even when going through calcification or a hard lesion site where a stent is placed, or the like.

Before use, the tip end portion of the balloon catheter is usually covered and protected by a protector, and when performing surgery, the protector is pulled out and the balloon catheter is used. One of the purposes of this protector is to prevent the balloon portion from being damaged before use. If the balloon portion is damaged by bending, the balloon tends to damage the inner wall of the blood vessel when passing through the lumen of the blood vessel, and the lumen of the guide wire is also bent, so that the resistance when pushing the balloon increases, and the balloon cannot be accurately guided to the lesion. In addition, when a damaged balloon is expanded, the balloon is easily broken or a pressure fluid leaks, which may cause a high risk and a serious medical accident.

The second purpose of adopting the protective tool is to reduce the outer diameter of the balloon as much as possible before the operation. The smaller the outer diameter of the balloon relative to the vessel lumen, the smaller the contact area between the balloon and the vessel wall, and the smaller the resistance when pushing the balloon, so that it becomes easier to guide the balloon to the lesion. In addition, in a lesion site where difficulty and flexibility are high, or in a site where surface resistance is high such as inside of a stent, the outer diameter of the balloon is kept small, and the permeability of the balloon to the lesion site can be improved.

In addition, before the operation, after the protector is pulled out from the balloon catheter, in order to prevent thrombus formation, a physiological saline solution or the like is supplied into the lumen of the guide wire to flush the lumen, or the balloon catheter is filled with a physiological saline solution, or the outer surface of the balloon catheter is immersed in a physiological saline solution. In particular, in flushing, in a balloon catheter of the type in which a guidewire lumen is connected from the proximal end of the catheter to the distal end (generally referred to as a "through-wire type"), a saline solution for flushing or the like can be supplied to the guidewire lumen through an orifice of a manifold provided at the proximal end of the catheter, and flushing is easy. However, the monorail balloon catheter is different from the through-wire balloon catheter. A balloon catheter of the single-rail type, in which a distal side catheter shaft is joined to a proximal side catheter shaft, a balloon is joined to a distal end of the distal side catheter shaft, a manifold having an orifice for supplying a pressure fluid to the balloon is provided at a proximal end of the proximal side catheter shaft, and a guidewire lumen extending in the longitudinal direction is formed inside the distal side catheter shaft. Since the rear end opening of the guide wire lumen is provided in the middle of the catheter shaft, the flushing fluid cannot be supplied to the guide wire lumen from the manifold provided on the proximal end side of the catheter. For this reason, conventionally, flushing is performed by inserting an injection needle having an outer diameter slightly equal to or slightly smaller than the inner diameter of the distal end opening of the guide wire lumen into the distal end opening, inserting an injection needle holding member holding the injection needle into the syringe, and supplying a flushing fluid to the guide wire lumen.

However, since the outer diameter of the distal end portion of the balloon catheter is extremely small, i.e., about 0.5mm to 3.0mm, the operation of inserting the needle into the guide wire lumen from the distal end opening portion and flushing the same is troublesome, and the distal end is liable to be bent, deformed into a horn shape, damaged, or the like. Thus, it is not easy to guide the balloon to the lesion site during the operation.

In view of the above problems, the object of the 4 th invention is to provide a balloon catheter equipped with a protector, which can flush the guidewire lumen of the balloon catheter without troublesome work and without causing deformation or damage to the tip portion of the balloon catheter.

Disclosure of Invention

In order to achieve the above object, the present invention provides a balloon catheter in which flexibility of a tip portion, which is the most distal end portion on the distal side of the balloon catheter, is improved by arranging selected materials, so that a difference in hardness between the tip portion and the vicinity of a guide wire or a balloon of the catheter is minimized, and operability is improved.

That is, the balloon catheter of the invention 1 is constituted by a plurality of tubular members and a balloon, and is characterized in that the 1 st tubular member is disposed so as to pass through the inside of the balloon, and one of the objects of the 1 st tubular member is to pass a slidable guide wire through the inside thereof, and the balloon is welded concentrically to the outer surface of the 1 st tubular member in the vicinity of the distal end of the catheter, and the outermost material constituting the 1 st tubular member has a shore hardness lower than the shore hardness of the material constituting the balloon. Therefore, the tip portion formed by fixing the 1 st tubular member and the balloon can be made flexible, and the above-described problem can be solved.

In a rapid-change type (single-track type) balloon catheter in which a tubular member (2 nd tubular member) constituting the outer surface of the catheter connected to the proximal side of the balloon is made of a material weldable to the balloon, and the catheter path is formed from the distal end of the catheter to the middle of the 2 nd tubular member, a catheter inlet portion is formed by welding the 2 nd tubular member to the 1 st tubular member in the middle of the 2 nd tubular member.

The balloon catheter of claim 2 is characterized in that the balloon is made of a thermoplastic elastomer having a hard segment and a soft segment, that is, a polymer blend material of a 1 st polymer component and a 2 nd polymer component, the 1 st polymer component has a higher shore hardness than the 2 nd polymer component, and both the 1 st polymer component and the 2 nd polymer component are thermoplastic elastomers having a hard segment having a structure of the same repeating unit and a soft segment having a structure of the same repeating unit.

The 1 st polymer component preferably has a Shore hardness (Duroc hardness) of D70 or more, and the 2 nd polymer component preferably has a Shore hardness of less than D70. The 1 st polymer component and the 2 nd polymer component are preferably polyester elastomers or polyamide elastomers. The 1 st polymer component (a) and the 2 nd polymer component (B) are preferably blended in a weight ratio of (a)/(B) of 98/2 to 10/90.

A balloon catheter according to claim 3, wherein a 1 st tubular member for passing a guide wire is disposed inside the 2 nd tubular member to form a catheter shaft, and a balloon is joined to a distal end of the catheter shaft; the balloon comprises a straight tube part, a proximal side conical part and a distal side conical part which are adjacent to two ends of the straight tube and gradually reduce the diameter, and a proximal side sleeve part and a distal side sleeve part which are adjacent to two ends of the conical part; at least one of the distal sleeve portion and the proximal sleeve portion has a shape in which a part of a start position of the taper portion adjacent to the sleeve portion is shifted in the axial direction, an inner surface of the distal sleeve portion is joined to an outer surface of the 1 st tubular member, and the proximal sleeve portion is joined to an end of the 2 nd tubular member. The shift in the longitudinal direction of the taper portion starting position adjacent to the sleeve portion is preferably in the range of 0.3mm to 10.0 mm.

The balloon catheter according to claim 3 is formed as a catheter shaft by disposing the 1 st tubular member for passing a guide wire inside the 2 nd tubular member, and joining the balloon to the distal end of the catheter shaft. The balloon comprises a straight tube portion, proximal and distal tapered portions adjacent to both ends of the straight tube portion and gradually reducing in diameter, and proximal and distal skirt portions adjacent to both ends of the tapered portion. The inclination angle of at least one of the distal tapered portion and the proximal tapered portion changes in the circumferential direction, and the inner surface of the distal sleeve is joined to the outer surface of the 1 st tubular member, and the proximal sleeve is joined to the end of the 2 nd tubular member. Here, the difference between the maximum value and the minimum value of the inclination angle is preferably in the range of 2 ° to 30 °.

In the above invention 3, the length of the straight tube portion in the major axis direction is preferably in the range of 8mm to 80 mm.

The balloon catheter according to claim 4 is characterized in that the balloon catheter is protected at its tip portion including the balloon by a protector having a protective tube portion covering the tip portion including the balloon and a connector detachably connected to the flushing fluid supply unit.

Thus, the distal end of the balloon catheter is inserted into the protective tube, and the connector is connected to a flushing fluid supply unit in a protected state, so that the flushing fluid can be supplied into the lumen of the balloon catheter for flushing by the flushing fluid supply unit. During this flushing operation, the tip of the balloon catheter is covered inside the protective tube, and therefore, the tip is prevented from being bent, deformed into a trumpet shape, or damaged.

In the case of using a syringe as the flushing fluid supply unit, and in the case of using a relatively small syringe, the connector is provided with a connection port to which the tip of the syringe barrel can be inserted. In the case of a relatively large syringe, the connector is provided with a luer lock coupling portion to be connected to a flushing fluid supply unit. The connector may be provided with a connection port to which the needle holder is inserted.

Drawings

Fig. 1 is an explanatory view showing a balloon catheter according to the present invention, in which a distal portion of the balloon catheter including a balloon and a tip portion is partially enlarged.

Fig. 2 is a schematic sectional view of a distal portion of the balloon catheter of the invention 1, including the balloon and the tip portion.

Fig. 3 is a schematic sectional view of the distal portion of the balloon catheter of the invention 1, including the balloon and the tip portion.

FIG. 4 is a sectional view A-A' of FIGS. 2 and 3, schematically showing an example of the tip portion of the balloon catheter of the invention 1.

Fig. 5 is a schematic sectional view of the distal portion of the balloon catheter including the balloon and the tip portion of the balloon catheter according to the first aspect of the present invention.

FIG. 6 is a sectional view B-B' of FIG. 5, schematically showing an example of the tip portion of the balloon catheter according to the invention 1.

FIG. 7 is a schematic sectional view showing the entire rapid-change balloon catheter according to the invention 1.

Fig. 8 is a schematic diagram of a measurement system for illustrating the effect of the invention 1.

Fig. 9 is a graph showing the expansion/contraction curve of example 5 of the present invention 2.

Fig. 10 is a graph showing the expansion/contraction curve of example 6 of the invention 2.

Fig. 11 is a graph showing the expansion/contraction curve of example 7 of the present invention 2.

Fig. 12 is a graph showing the expansion/contraction curve of example 8 of the present invention 2.

Fig. 13 is a graph showing expansion and contraction curves of example 6 of the invention 2 and comparative example 7.

Fig. 14 is a graph showing the expansion/contraction curve of example 9 of the invention 2.

Fig. 15 is a graph showing expansion and contraction curves of comparative example 8 and comparative example 9 of the 2 nd invention.

Fig. 16 is a schematic view showing an experimental environment for observing the passing performance of the balloon catheter of the 2 nd invention.

FIG. 17 is a schematic sectional view showing a 1 st embodiment of the balloon catheter of the invention 3.

Fig. 18 is an explanatory diagram showing a state of wings generated in the balloon catheter according to embodiment 1.

FIG. 19 is a schematic sectional view showing a balloon catheter of embodiment 2 of the invention 3.

Fig. 20 is an explanatory diagram showing a state of wings generated in the balloon catheter according to embodiment 2.

FIG. 21 is a schematic sectional view showing the dimensions of each part of the balloon in example 10.

FIG. 22 is a schematic sectional view showing the dimensions of each part of the balloon in comparative example 10.

Fig. 23 is a schematic view illustrating an experimental environment of the balloon catheter of the invention 3.

FIG. 24 is a schematic view showing the dimensions of each part of the balloon in example 11.

Fig. 25 is a schematic cross-sectional view showing a state of a straight tube portion of a balloon catheter, wherein (a) is a folded state, (b) is an expanded state, and (c) is a state in which a wing is generated.

Fig. 26 is a schematic explanatory view showing a state where the balloon catheter with the wings is in contact with a stricture.

Fig. 27(a) is a schematic cross-sectional view showing an example of the balloon catheter protector according to the 4 th invention, and (b) is a right side view of the balloon catheter protector.

Fig. 28 is a schematic cross-sectional view showing an example of the balloon catheter protector for protecting the tip of the balloon catheter.

Fig. 29 is a schematic sectional view showing a state in which the syringe and the connector are connected.

Fig. 30 is a schematic cross-sectional view showing a state where the syringe and the connector are coupled by luer lock.

Detailed Description

Next, an example of the balloon catheter of the present invention will be described. Fig. 1 is a side view showing a main cross section of a conventional through-wire balloon catheter. The balloon catheter 1 includes a catheter shaft 2, a balloon 3 joined to a distal end of the catheter shaft 2, and a manifold 4 connected to a proximal end of the catheter shaft 2. In the illustrated example, the vicinity of the tip end including the balloon 3 is shown enlarged from the actual size for the sake of convenience of explanation.

The catheter shaft 2 has a double-tube structure of an inner tube and an outer tube, and is composed of a 1 st tubular member 5 and a 2 nd tubular member 6 for passing a guide wire therethrough, and the 2 nd tubular member 6 forms a filling lumen for supplying a pressure fluid such as a contrast medium or a physiological saline to the balloon 3. The manifold 4 located at the proximal end is provided with ports 9 and 10 communicating with the guidewire lumen 7 and the filling lumen 8, respectively, through which a guidewire passes. Thus, the balloon catheter 1 having a double tube structure of the inner 1 st tubular member 5 and the outer 2 nd tubular member 6 is also referred to as a coaxial type (Co-axial type). The balloon 3 is tubular, and has tapered portions 12 and 13 with gradually decreasing diameters at both ends of a straight tube portion 11, and sleeve portions 14 and 15 at both ends of the tapered portions 12 and 13. The 1 st tubular member 5 is extended from the distal end of the 2 nd tubular member 6, the proximal-side sleeve portion 15 is fitted over the distal end of the 2 nd tubular member 6, and the distal-side sleeve portion 14 is joined to the balloon 3 in the vicinity of the distal end of the 1 st tubular member 5. The tip portion of the balloon 3 (the tip portion including the most distal end 16 of the 1 st tubular member 5 and the distal-side sleeve portion 14 penetrating the balloon 3) is referred to as a tip portion and is denoted by reference numeral 17 in the drawing. In the 2 nd tubular member 6, in order to improve the push pressure transmissibility, a plurality of different tubular materials are used on the proximal side and the distal side.

The balloon catheter of the present invention, as shown in fig. 1, is composed of a plurality of tubular members and a balloon. The 1 st invention will be described with reference to fig. 1 to 8. Fig. 2, 3 and 5 are sectional views showing a distal portion of the balloon catheter 1 according to the invention 1, including the balloon 3 and the tip portion 17. Fig. 7 is an overall sectional view schematically illustrating the rapid-exchange balloon catheter according to claim 1.

In fig. 2, the 1 st tubular member 5 having the guide wire passage lumen 7 is disposed so as to penetrate the inside of the balloon 3, and is welded to the balloon 3 concentrically with the tip portion 17 at the distal end of the catheter as shown in the cross-sectional view of fig. 4. The other end of the balloon 3 is connected to a 2 nd tubular member 6 constituting the outside of the catheter. The 1 st tubular member 5 has a structure in which a plurality of layers of material are formed in the radial direction along the entire length thereof, and the outermost material layer 18 and the innermost material layer 19 are integrally formed with each other with an adhesive layer 20 interposed therebetween. Therefore, the outermost material layer 18 constituting the 1 st tubular member 5 is welded to the distal-side sleeve portion 14 of the balloon 3.

In fig. 3, the 1 st tubular member 5 having the guide wire passage lumen 7 is disposed so as to penetrate the balloon 3, and as shown in a cross-sectional view in fig. 4, the tip portion 17 is formed at the tip end of the catheter by heat welding concentrically with the balloon 3, the material layer 21 adjacent to the balloon 3, and the adhesive layer. The other end of the balloon 3 is connected to a 2 nd tubular member 6 constituting the outside of the catheter. The most distal end portion of the 1 st tubular member 5 has a multi-layer material structure in the radial direction, and the material layer 21 adjacent to the balloon 3 and the material layer 22 constituting the innermost surface are integrated with each other by an adhesive layer 23. Therefore, the material layer 21 of the 1 st tubular member 5 is welded to the distal-side sleeve portion 14 of the balloon 3.

In fig. 5, the 1 st tubular member 5 having the guide wire passage lumen 7 is disposed so as to penetrate the inside of the balloon 3, and at the tip end of the catheter, as shown in a cross-sectional view in fig. 6, a tip portion 17 is formed by welding a material layer 24 adjacent to the balloon 3 concentrically with the balloon 3. The other end of the balloon 3 is connected to a 2 nd tubular member 6 constituting the outside of the catheter. The most distal portion of the 1 st tubular member 5 has a multi-layer material structure in the radial direction, and the material layer 24 adjacent to the balloon 3 and the material layer 25 constituting the innermost surface are directly integrated. Therefore, the material layer 24 of the 1 st tubular member 5 is welded to the distal-side sleeve portion 14 of the balloon 3.

The 1 st invention is characterized in that at least one of the shore hardness, bending modulus, and melting point of the material of the 1 st tubular member 5, which is at least the outermost material of the welded portion with the balloon 3, or the material of the adjacent layer to the balloon, is lower than the material of the balloon 3.

The material of the inner surface of the 1 st tubular member 5 is not particularly limited, and may be formed of the same material as the outermost surface, or may be a single-layer tubular member as long as the minimum conductor slidability is secured. In general, a material having low shore hardness, bending modulus, and melting point is inferior in sliding property, and therefore, it is preferable that the inner surface is formed of a material having good sliding property different from that of the outer surface. The innermost surface is preferably made of high density polyethylene, or high hardness polyester, polyamide elastomer, or polyester elastomer. In this case, a material layer or an adhesive layer for providing the pipe member with good mechanical properties may be interposed between the outermost surface and the innermost surface. The number, kind, and thickness ratio of the interposed layers are not particularly limited. For example, when forming a single adhesive layer, the conventional lamination technique or adhesion technique may be used, or a material having an intermediate solubility parameter (SP value) of the outermost and innermost material layers may be disposed alone or in a plurality of layers, or a material having adhesion to the outermost and innermost surfaces may be disposed.

When the outermost layer is formed of a thermoplastic elastomer such as a polyester elastomer or a polyamide elastomer, the calculated flexural rigidity of the elastomer layer is preferably controlled to be higher than that of the other layers. The soft segment proportion of the outermost layer is preferably greater than 13% when the layer is formed of a polyester elastomer, and is preferably less than 70%, preferably between 13% and 47%, in order to provide a higher calculated stiffness of the elastomer layer than the other layers, and in order to provide for the balloon not to deform extremely on expansion and pressurization. Similarly, when the outermost layer is formed of a polyamide elastomer, the soft segment proportion is preferably more than 14%. In order to make the elastomer layer more rigid than the other layers and not to deform extremely when the balloon is inflated and pressurized, the soft segment proportion is preferably less than 70%.

The 1 st tubular member 5 having the structure shown in the 1 st invention can be used as the entire tubular member, but it is preferable that at least the outermost material layer of the welded portion with the balloon 3 is formed so that the tip end portion 17 can be made flexible even when the material has a lower shore hardness, bending modulus, and melting point than the material constituting the balloon, and therefore the tip end portion 17 is not required to have the strength of the main body portion and can be made flexible enough to ensure the strength of the main body portion sufficiently. Similarly, when the balloon 3 and the 1 st tubular member 5 are fixed by thermal welding, the thermal welding is performed by thermal welding at least one layer of a material compatible with the balloon 3 and the 1 st tubular member 5 or a material chemically reactive with the balloon 3 and the 1 st tubular member 5 as a direct fixed layer or a fixed portion in a partial lamination. Even if the material layer adjacent to the balloon 3 has at least one of a shore hardness, a bending modulus of elasticity, and a melting point lower than that of the material constituting the balloon 3, the tip portion 17 can be made flexible, and therefore, the tip portion 17 is not required to have the strength of the main body portion while the strength of the main body portion is sufficiently ensured, and it is preferable that the tip portion 17 can be made sufficiently flexible.

Further, the invention according to claim 1 is characterized in that the shore hardness of the outermost material layer of the 1 st tubular member 5 to be welded to at least the balloon 3, or the material layer adjacent to the balloon 3 when the balloon 3 is fixed to the 1 st tubular member 5 by thermal welding, is lower than the material constituting the balloon 3. The heat fusion is performed by heat-fusing a material compatible with the balloon 3 and the 1 st tubular member 5 or a material chemically reactive with the balloon 3 and the 1 st tubular member 5 as a direct anchoring layer or as at least one layer when the anchoring portion is multilayered. However, the shore hardness of the outermost material layer of the 1 st tubular member 5, which is welded to at least the balloon 3, is preferably 10D or more, more preferably 12D to 30D, smaller than the shore hardness of the material constituting the balloon 3.

Further, the invention of claim 1 is characterized in that the bending modulus of the layer adjacent to the balloon 3 when the outermost material layer of the 1 st tubular member 5 to be welded to at least the balloon 3 or the fixation of the balloon 3 to the 1 st tubular member 5 is performed by thermal fusion (the thermal fusion is performed by thermal fusion of a material compatible with the balloon 3 and the 1 st tubular member 5 or a material chemically reactive with the balloon 3 and the 1 st tubular member 5 as a direct fixation layer or as at least one layer when the fixation portion is partially laminated) is lower than that of the material constituting the balloon 3. However, the bending modulus of the outermost layer of the 1 st tubular member, which is welded to at least the balloon 3, is preferably smaller than the bending modulus of the material constituting the balloon 3 by 100MPa or more, and is preferably different from 234MPa to 337 MPa.

The Shore hardness (Duroc hardness) described in the invention 1 can be measured by the method of JIS K7215 or ASTM2240, and the flexural modulus can be measured by the method of ASTM 790. The melting point can be measured by using a conventional DSC measuring apparatus. In addition, the Shore hardness is generally classified into two types, type A and type D, and the Shore hardness in the present invention is the type D hardness. The ratio of the hard segment to the soft segment in the material of the invention 1 is a weight ratio of each component in the material and can be measured by NMR.

Specific examples and comparative examples of invention 1 will be described in detail below, and the following examples do not limit invention 1.

(example 1)

A 1 st tubular member for passing a wire, which forms an outermost layer, and is composed of a polyester elastomer having a Shore hardness of 60D, a bending modulus of elasticity of 274MPa, a melting point of 216 ℃, and a soft segment (ソフトセグメント) ratio of 22%; the innermost face is composed of high density polyethylene. The 1 st tubular member was passed through the inside of a balloon made of a polyester elastomer having a Shore hardness of 72D, a bending modulus of elasticity of 568MPa, a melting point of 218 ℃ and a soft segment ratio of 13%, and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member to form a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 2. In example 1, the 2 nd tubular member connected to the balloon proximal side and constituting the outer surface of the catheter is made of a polyester elastomer weldable to the balloon, and the guidewire inlet portion can be formed by welding the 2 nd tubular member to the 1 st tubular member, which is convenient in manufacture.

(example 2)

A 1 st tubular member for passing a wire, which forms an outermost layer, and is composed of a polyamide elastomer having a Shore hardness of 55D, a bending modulus of elasticity of 196MPa, a melting point of 168 ℃, and a soft segment ratio of 35%; the innermost face is composed of high density polyethylene. The 1 st tubular member was passed through the inside of a balloon made of a polyamide elastomer having a Shore hardness of 70D, a bending modulus of elasticity of 430MPa, a melting point of 172 ℃ and a soft segment ratio of 14%, and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member to form a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 2. In example 2, the 2 nd tubular member connected to the balloon proximal side and constituting the outer surface of the catheter is made of a polyamide elastomer weldable to the balloon, and the guide wire inlet portion can be formed by welding the 2 nd tubular member to the 1 st tubular member, which is convenient in production.

(example 3)

A 1 st tubular member for passing a lead wire, which forms an outermost layer of a portion welded to a balloon and is composed of a polyamide elastomer having a Shore hardness of 40D, a bending modulus of 93MPa, a melting point of 168 ℃ and a soft segment ratio of 47%; the body and the innermost surface of the balloon-welded portion are made of high-density polyethylene. The 1 st tubular member was passed through the inside of a balloon made of a polyamide elastomer having a Shore hardness of 70D, a bending modulus of elasticity of 430MPa, a melting point of 172 ℃ and a soft segment ratio of 14%, and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member, and a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 7 was produced. Reference numeral 26 in fig. 7 denotes a lead wire introduction opening.

(example 4)

A 1 st tubular member for passing a lead wire, which forms an outermost layer of a portion welded to a balloon and is composed of a polyamide elastomer having a Shore hardness of 40D, a bending modulus of 93MPa, a melting point of 168 ℃ and a soft segment ratio of 47%; the body and the innermost surface of the balloon-welded portion are composed of a polyamide elastomer having a Shore hardness of 75D, a flexural modulus of elasticity of 550MPa, a melting point of 177 ℃, and a soft segment ratio of 5%; the 1 st tubular member was passed through the inside of a balloon made of a polyamide elastomer having a melting point of 172 ℃ and a soft segment ratio of 14%, and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member, and a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 5 was manufactured.

Comparative example 1

A 1 st tubular member for passing a wire, which forms an outermost layer, and is composed of a polyester elastomer having a Shore hardness of 72D, a bending modulus of elasticity of 568MPa, a melting point of 218 ℃ and a soft segment ratio of 13%; the innermost face is composed of high density polyethylene. The 1 st tubular member was passed through the inside of a balloon made of a polyester elastomer having a Shore hardness of 72D, a bending modulus of elasticity of 568MPa, a melting point of 218 ℃ and a soft segment ratio of 13%, and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member to form a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 2.

Comparative example 2

A 1 st tubular member for passing a wire, which forms an outermost layer, and is composed of a polyamide elastomer having a Shore hardness of 70D, a bending modulus of elasticity of 430MPa, a melting point of 172 ℃ and a soft segment ratio of 14%; the innermost face is composed of high density polyethylene. The 1 st tubular member was passed through the inside of a balloon made of a polyamide elastomer having a Shore hardness of 70D, a bending modulus of elasticity of 430MPa, a melting point of 172 ℃ and a soft segment ratio of 14%, and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member to form a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 2.

Comparative example 3

A1 st tubular member for passing a guide wire therethrough is composed of a high-density polyethylene having a Shore hardness of 70D, a bending modulus of elasticity of 400MPa and a melting point of 135 ℃, and the 1 st tubular member is passed through the inside of a balloon composed of a crosslinked low-density polyethylene having a Shore hardness of 57D, a bending modulus of 210MPa and a melting point of 117 ℃ and has a nominal expansion value of 3.0 mm. The distal tip of the balloon is concentrically welded to the outer surface of the 1 st tubular member, and a quick-change type coronary balloon catheter having a catheter distal portion as shown in fig. 2 is manufactured.

Comparative example 4

A1 st tubular member for passing a wire therethrough, which forms an outermost layer, is composed of polyamide having a melting point of 178 ℃ and an innermost layer of high density polyethylene. The 1 st tubular member was passed through the interior of a balloon made of polyamide having a melting point of 178 ℃ and a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member to form a commercial rapid exchange type balloon catheter for coronary arteries.

Comparative example 5

The 1 st tubular member for passing the wire therethrough was composed of a polyamide elastomer having a melting point of 176 ℃ and a soft segment ratio of 7%. The 1 st tubular member was passed through the interior of a balloon made of a polyamide elastomer having a melting point of 173 ℃ and a soft block ratio of 17%, and having a nominal expansion value of 3.0 mm. The distal end of the balloon was concentrically welded to the outer surface of the 1 st tubular member to form a commercial rapid exchange type balloon catheter for coronary arteries.

(evaluation)

The balloon catheter of the invention 1, i.e., the tip portions of examples 1, 2, 3, and 4, were softer than any of comparative examples 1, 2, 3, 4, and 5. In addition, examples 1, 2, 3 and 4 and comparative examples 1, 2, 3, 4 and 5 were placed in a curved simulated body-fluid passage 27 as an evaluation system shown in FIG. 8, and the curved simulated body-fluid passage 27 was made of a polyethylene tube having a curvature of 5mm and a 90-degree bend with an inner diameter of 1.5mm, a lead wire was placed inside the tube, and a physiological saline solution at 37 ℃ was circulated. The balloon catheter 1 is advanced along the guide wire 28 at a constant speed, and the load acting on the balloon catheter when the tip portion 17 passes through the bent portion is measured. That is, the load cell 30 to which the shaft 2 is fixed is moved in a constant direction at a constant speed on the slide table 29, and the load applied to the load cell 30 is measured. In order to protect the inner surface of the simulated in vivo passage, i.e., the polyethylene pipe, from the balloon catheter surface coating, a hydrophilic coating was applied. The balloon of the balloon catheter is folded around the 1 st tubular member for passing a guide wire, and measurement is performed.

The results are shown in Table 1. Examples 1, 2, 3 and 4 of the invention 1 are superior to the comparative examples in that the load on the tip portion of the balloon catheter simulated in the body passage by bending is small, and the tip portion is flexible and has good operability.

TABLE 1

	Peak load (N)
		Example 1	0.118
Example 2	0.098
		Example 3	0.077
Example 4	0.095
		Comparative example 1	0.333
Comparative example 2	0.314
		Comparative example 3	0.441
Comparative example 4	0.343
		Comparative example 5	0.265

Next, referring to fig. 9 to 16, the balloon catheter according to the 2 nd embodiment of the present invention will be described. The balloon catheter according to claim 2 is characterized by being made of a polymer blend material for a balloon. The polymer blend material is a polymer blend material of a 1 st polymer component and a 2 nd polymer component, which are composed of a thermoplastic elastomer having a hard segment and a soft segment such as a polyolefin elastomer, a polyamide elastomer, a polyester elastomer, or a polyurethane elastomer. The 1 st polymer component has a higher shore hardness (duro hardness) than the 2 nd polymer component, and the 1 st polymer component and the 2 nd polymer component both have a hard segment having the same repeating unit structure and a soft segment having the same repeating unit structure. Has a hard segment having high crystallinity and strong cohesion, and imparts tensile strength to the balloon. Since a soft segment having low crystallinity and a polar group imparts flexibility to a balloon, a balloon containing two blocks has flexibility, toughness and elasticity.

The soft segment main body may be made of one or more materials such as polyether represented by PTMG (polytetramethylene glycol) and polyester represented by PCL (polycaprolactone). The main body of the hard segment is one or more materials such as polyester typified by PBT (polybutylene terephthalate) and PET (polyethylene terephthalate), polyamide typified by nylon 11 and nylon 12, and polyurethane. As the block copolymer contained in the repeating units, a polyamide elastomer such as "ハイトレル" (manufactured by Toyo DuPont (Toyo Boseki Kabushiki Kaisha)), a polyamide elastomer such as "ペルプレン" (manufactured by Toyo Kabushiki Kaisha) and a trade name of "ヌ - ベラン" (manufactured by Dimai Kabushiki Kaisha), a polyurethane elastomer such as "PEBAX" (manufactured by e1f atochem Kaisha), a polyurethane elastomer such as "ミラクトラン" (manufactured by Nippon ミラクトラン Kaisha) and a polyurethane elastomer such as "ペレセン" (manufactured by ダウ - プラスチツク Kaisha) are preferable.

The 1 st polymer component (A) and the 2 nd polymer component (B) preferably have Shore hardnesses of D70 or more and D70 or less. The weight ratio (A)/(B) of the two components is 98/2 to 10/90, preferably 95/5 to 20/80. If the blending ratio of the two components exceeds 98/2, the balloon as a molded article has poor flexibility and the operability of the balloon catheter for the operator is reduced; if the blending ratio is less than 10/90, the required compressive strength of the balloon cannot be easily obtained. For example, the above-mentioned "ハイトレル" has several grades in terms of hardness, and each grade is related to the weight ratio of the hard segment (PBT) to the soft segment (polyether), and 2 or more kinds of "ハイトレル" having different grades (Shore hardness) are mixed to optimize the mixing ratio. Since other elastomers such as "ヌ - ベラン" have various grades corresponding to the hardness, they can be blended by the same method as "ハイトレル".

Thus, the 1 st polymer component and the 2 nd polymer component are composed of the same thermoplastic elastomer, that is, the thermoplastic elastomer having the hard segment having the same repeating unit structure and the soft segment having the same repeating unit structure, and the Shore hardness of both components is changed within the above range, whereby the blending ratio can be optimized, and the both components can be easily mixed, whereby a polymer blend material having flexibility, high compressive strength, and appropriate expansion and contraction can be easily produced

Balloon with a specific ratio (expansion/contraction characteristic).

The method of mixing the above-mentioned 1 st polymer component and 2 nd polymer component is not particularly limited, and it may be dry mixing without a liquid, which is mechanically homogeneously mixed, wet mixing in which a liquid material is mixed, or granulating after mixing both components.

The method for molding the balloon using the polymer blend is not particularly limited, but blow molding is preferably employed in order to obtain sufficient pressure resistance. For example, a tubular blank is first formed into a tubular shape of an arbitrary size by an extrusion method or the like, the blank is extended to a predetermined length and preformed as necessary, and then transferred into a cavity of a blow molding die, the die is closed, and the blank is axially and radially extended in a biaxial extension step, and then subjected to toughening treatment to produce a balloon. The biaxial stretching step may be performed several times, and the stretching in the axial direction may be performed simultaneously with or before the stretching in the radial direction. In addition, the balloon may be subjected to heat-fixing treatment in order to stabilize the shape and size of the balloon.

The shore hardness, bending modulus, and melting point of the balloon of the invention 2 can be measured by the same methods as those of the above invention 1.

The balloon catheter with a balloon according to the embodiment of the invention 2 also has the basic structure shown in fig. 1.

In fig. 1, the 1 st tubular member 5 for passing the lead wire is a through-wire type extending along the entire length of the catheter shaft 2, but the 2 nd invention is not limited thereto, and may be a monorail type in which the 1 st tubular member 5 is disposed only at a position of 20 to 30cm from the tip. The polymer blend material can be used for manufacturing various medical instruments in addition to balloons.

Specific examples and comparative examples of invention 2 will be described in detail below, and the following examples do not limit invention 2.

(example 5)

A polymer blend was prepared by blending 90 wt% of a polyester elastomer (trade name: ペルプレン, type S-6001, available from Toyo Boseki Co., Ltd., Shore D72, hard segment PBT, soft segment PCL) as a 1 st polymer component and 10 wt% of a polyester elastomer (trade name: ペルプレン, type S-3001, available from Toyo Boseki Co., Ltd., Shore D60, hard segment PBT, PCL) as a 2 nd polymer component, and a tubular preform (inner diameter: 0.43mm, outer diameter: 0.89mm) was prepared by extrusion molding using the polymer blend, and 20 balloons (straight tube portion: 3.0mm in outer diameter, wall thickness: about 18 μm) of this example were prepared by biaxial stretch blow molding using the preform.

(example 6)

A polymer blend material was prepared by blending 70 wt% of the 1 st polymer component and 30 wt% of the 2 nd polymer component, and 20 balloons of this example (straight tube portion having an outer diameter of 3.0mm and a wall thickness of about 19 μm) were prepared in the same manner as in example 5 except that the balloon had a wall thickness of 19 μm.

(example 7)

20 balloons (straight tube portions having an outer diameter of 3.0mm and a wall thickness of about 18 μm) of this example were produced in the same manner as in example 5 except that 50 wt% of the 1 st polymer component and 50 wt% of the 2 nd polymer component were blended to prepare a polymer blend material.

(example 8)

A polymer blend material was prepared by blending 30 wt% of the 1 st polymer component and 70 wt% of the 2 nd polymer component, and 20 balloons of this example (straight tube portion having an outer diameter of 3.0mm and a wall thickness of about 19 μm) were prepared in the same manner as in example 5 except that the balloon had a wall thickness of 19 μm.

Comparative example 6

20 balloons of this comparative example (straight tube portion having an outer diameter of 3.0mm and a wall thickness of about 20 μm) were prepared in the same manner as in example 5 except that only the polymer component 1 was used and the wall thickness of the balloon was 20 μm.

Comparative example 7

20 balloons of comparative example 7 (straight tube portion having an outer diameter of 3.0mm and a wall thickness of about 20 μm) were prepared in the same manner as in example 5 except that only the polymer component 2 was used and the wall thickness of the balloon was 20 μm.

(example 9)

A polyamide elastomer (trade name "PEBAX", model No. 7233SA00 ", manufactured by elf atom Co., Ltd., Shore D72, hard segment: nylon 12, soft segment: PTMG) as a 1 st polymer component and 50 wt% of a polyamide elastomer (trade name" PEBAX ", model No. 6333SA 00", manufactured by elf atom Co., Ltd., Shore D63, hard segment: nylon 12, soft segment: PTMG) as a 2 nd polymer component were mixed to prepare a polymer blend, and a tubular blank (inner diameter 0.43mm, outer diameter 0.94mm) was prepared by extrusion molding using the polymer blend, and then 20 balloons of this example (straight tube portion outer diameter 3.0mm, wall thickness about 19 μm) were prepared by biaxial stretch blow molding using this blank.

Comparative example 8

20 balloons of this comparative example (straight tube portion having an outer diameter of 3.0mm and a wall thickness of about 20 μm) were prepared in the same manner as in example 9, except that only the polymer component 1 was used and the wall thickness of the balloon was 20 μm.

Comparative example 9

20 balloons of this comparative example (straight tube portion having an outer diameter of 3.0mm and a wall thickness of about 19 μm) were prepared in the same manner as in example 9, except that only the polymer component 2 was used and the wall thickness of the balloon was 19 μm.

(test for flexibility)

Using the balloons of examples 5 to 9 and comparative examples 6 to 9, tests were conducted on stretchability. In a water tank filled with physiological saline at 37 ℃, 10 balloons were placed, and the internal pressure (expansion pressure) of each balloon was increased by 0.2atm at a time in the range of 2atm to 20atm with the physiological saline, and the pressure value state was maintained for 1 second. Further, for each 1atm rise in the internal pressure, the outer diameter of the balloon was measured by a laser measuring instrument, and an expansion pressure-balloon outer diameter curve (expansion curve) was prepared. The results are shown in fig. 9 (example 5), fig. 10 (example 6), fig. 11 (example 7), fig. 12 (example 8), fig. 13 (comparative example 6, comparative example 7), fig. 14 (example 9), and fig. 15 (comparative example 8, comparative example 9). The values shown in each figure are the average of 10 measured values.

At the same time, the internal pressure of the balloon was increased to cause the balloon to break, and the breaking pressure was measured. The results ("mean breaking pressure") are shown in Table 2. The values shown in the table are the average of 10 measured values.

(balloon catheter sample)

Next, balloon catheter samples using the balloons of examples 5 to 9 and comparative examples 6 to 9 were prepared, and the performance of the samples was observed. These balloon catheter samples, as shown in fig. 1, had a catheter shaft 2 of a double-tube structure having a 1 st tubular member 5 and a 2 nd tubular member 6, and a balloon 3 was joined to the distal end of the catheter shaft 2. In addition, there is no manifold 4. After the balloon was partially folded, EOG sterilization was performed to prepare 10 balloon catheter samples each.

(relevant pass (クロス) Performance test)

As shown in fig. 16, a U-shaped simulated-bending stenotic vessel plate 31 was placed in 37 ℃ physiological saline, and the resistance value when a balloon catheter sample was inserted into the simulated-bending stenotic vessel plate 31 was measured. A U-shaped narrow blood vessel plate 31 is formed by simulating bending of a U-shaped groove 32 formed on the surface of an acrylic substrate 32, polyethylene tubes 33, 34 having an inner diameter of 3.0mm are fixedly arranged along the U-shaped groove 32, a polyethylene tube 35 having an inner diameter of 0.95mm and an outer diameter of 2.98mm is coaxially fixedly arranged at the bending portion of the U-shaped groove 32, and the polyethylene tube 35 is coaxially arranged and fixed in a semicircular shape having a diameter of 150 mm.

The proximal end portion of the catheter shaft 2 is held by a clip 37 connected to a force gauge 36, the force gauge 36 is attached to a slide table 38, and the slide table 38 is movable in the proximal and distal directions with respect to the U-shaped virtual curved stenosed blood vessel plate 31.

The guide wire 38 was inserted into the lumen of the above-mentioned pseudo-curved stenosed blood vessel composed of polyethylene tubes 33, 34 and 35, the force gauge 36 was moved toward the plate 31 at a speed of 10mm/sec, the balloon catheter sample 1 was advanced along the guide wire 39, and the maximum resistance value (load acting on the force gauge 36) at the time of passing through the pseudo-curved stenosed blood vessel was recorded as "resistance value at the time of initial passage". The results are shown in table 2 below. The values shown in the table are the average of 10 balloon catheter samples.

After the measurement of the resistance value at the initial passage, the balloon catheter sample was withdrawn to the inlet of the pseudo-tortuous stenosed vessel, and the balloon 3 was inflated with physiological saline at an internal pressure of 10atm for 60 seconds. Then, the balloon was rapidly deflated and the sample was advanced through the simulated curved stenosed vessel at a speed of 10mm/sec while maintaining the negative pressure, and the maximum resistance value at the time of passing was recorded as "resistance value at the time of passing". The results are shown in table 2 below. The values shown in the table are the average of 10 balloon catheter samples.

TABLE 2

	Resistance value (N) at initial passage	Resistance value when passing (N)	Mean pressure of failure (atm)	Standard deviation of mean breaking pressure (atm)	Rated breakdown pressure (atm)
						Example 5	0.12	0.23	19.1	0.55	15.7
Example 6	0.15	0.21	20.4	0.49	17.4
						Example 7	0.10	0.25	19.2	0.38	16.8
Example 8	0.11	0.19	19.3	0.71	14.9
						Comparative example 6	0.23	0.60	22.9	0.72	18.4
Comparative example 7	0.10	0.21	14.4	0.59	10.7
						Example 9	0.08	0.18	20.7	0.70	16.4
Comparative example 8	0.28	0.72	23.3	0.62	19.5
						Comparative example 9	0.06	0.16	16.4	0.81	11.4

Regarding the safety of the balloon, the Rated Breakdown Pressure (RBP) defined by the FDA guidelines (Food and drug administration guidelines) in the united states is determined by the following equation (1).

RBP＝X-(K+1)D (1)

In the formula, RBP: rated breakdown voltage, X: average breaking pressure, D: standard deviation of mean breaking pressure, K: is a coefficient determined by the calculated reliability (C), the accuracy (P) and the number of samples (n) of the average failure pressure. The coefficient K may be found in accordance with the table provided by FDA guidelines. Now, since C is 0.95, P is 0.999, and n is 10, K is 5.203. The values of "standard deviation of mean breaking pressure" (D) and "rated breaking pressure" (RBP) of the examples and comparative examples are shown in table 2 above.

In order to expand a lesion site to which the graft-fixing sheet is placed after the graft-fixing sheet is placed at the lesion site, a Rated Breakdown Pressure (RBP) of at least 14atm is required for the pressure-resistant strength of a balloon catheter having a high nominal diameter of 3.0mm, which is required in recent medical practice. Therefore, as is clear from the above formula (1), the average breakdown pressure (X) must be 20 atm. Further, the lower the resistance when the catheter enters the blood vessel stenosis portion, the easier the catheter enters the stenosis portion, and the higher the passability and operability of the balloon catheter. That is, the lower the "resistance value at the initial passage" is, the better the initial passage performance is, and the lower the "resistance value at the re-passage" is, the better the re-passage performance is. In addition, if the resistance value is about 0.2N, the operator operating the balloon catheter assumes high passability.

(evaluation)

The above examples and comparative examples were evaluated based on the above criteria. Examples 5 to 8, comparative examples 6 and comparative example 7, which used polymer blends, were evaluated. In the above-mentioned polymer blend material, the 1 st polymer component and the 2 nd polymer component are composed of a polyester elastomer.

In the samples of examples 5 to 8, "resistance value at the time of initial passage" and "resistance value at the time of passage" were in the range of 0.10N to 0.25N, and the permeability and handling properties of the samples were evaluated to be very high. The "average breakdown pressure" distribution in examples 5 to 8 was in the range of 19.1 to 20.4atm, and was a value that could reach the rated breakdown pressure of 14 atm.

In contrast, in the sample of comparative example 6, the "average rupture pressure" was 22.9atm, which was a value that the rated rupture pressure was 14atm, but the "resistance value at the time of passing through" was very high, and the passability and the handling property were far inferior to those of the examples. In the sample of comparative example 7, the "initial passing resistance value" and the "passing resistance value" were 0.21N or less, and the passability and the handling property were high, but the "average breaking pressure" was extremely low, and was only 14.4atm, and the rated breaking pressure of 14atm could not be achieved.

In addition, from the above-mentioned expansion and contraction curves, the samples of examples 5 to 8 were not clearly different from those of fig. 9 to 12, but were almost no different from those of comparative example 6 shown in fig. 13, and maintained the semi-expansion and contraction characteristics extremely similar to those of no expansion and contraction, and had sufficient compressive strength and flexibility.

In contrast, in the sample of comparative example 6, as shown in fig. 13, although the semi-stretching property similar to the non-stretching property was obtained, the "resistance value at the time of passing" was very high as described above, and the flexibility was insufficient. In addition, since the sample of comparative example 7 exhibits a semi-stretching property similar to the stretchability, it is easy to excessively expand the blood vessel wall.

Example 9, comparative example 8 and comparative example 9 using the polymer blend were evaluated. In the polymer blend material, the 1 st polymer component and the 2 nd polymer component are composed of a polyamide elastomer.

In the sample of example 9, the "resistance value at the initial passage" and the "resistance value at the passage" were in the range of 0.08N to 0.18N, and the specimen was evaluated to have extremely high passability and handling property. The "average breakdown pressure" is in the range of 20.7atm, and a value of 14atm of the rated breakdown pressure can be achieved.

In contrast, in the sample of comparative example 8, the "average rupture pressure" was 23.3atm and the rated rupture pressure was 14atm, but the "initial resistance value at the time of passage" and the "resistance value at the time of passage" were very high, and the passability and the handling property were far inferior to those of the examples. In the sample of comparative example 9, the "resistance value at the initial passage" and the "resistance value at the passage" were 0.16N or less, but the "average breaking pressure" was low, i.e., 16.4atm, and the rated breaking pressure of 14atm could not be achieved, although the passability and the operability were high.

From the above-described expansion/contraction curves, example 9 (fig. 14) and comparative example 8 (fig. 15) were almost no inferior, and they maintained the semi-expansion/contraction characteristics extremely similar to the non-expansion/contraction characteristics, and had sufficient compressive strength and flexibility.

In contrast, in the sample of comparative example 8, as shown in fig. 15, the semi-stretching property similar to the non-stretching property was obtained, but as described above, the "resistance value at the time of passing" was very high, and the flexibility was insufficient. In addition, the sample of comparative example 9 exhibits a semi-stretching property similar to the stretchability, and therefore tends to excessively expand the blood vessel wall.

Next, referring to fig. 17 to 26, examples of the balloon catheter of the invention 3 will be described.

When the balloon catheter 1 is supplied as a product, as shown in the sectional view of fig. 25(a), the balloon 3 is contracted and folded around the 1 st tubular member 5 for passing a guide wire with its outer diameter minimized. Therefore, at the time of initial use, the balloon 3 passes through the stenosis portion without difficulty, and as shown in the sectional view of fig. 25(b), the internal pressure is increased to expand the balloon 3. However, even if the balloon 3 is deflated when it is taken out of the body, the balloon cannot return to the folded state shown in fig. 25(a), but is expanded horizontally in the radial direction as shown in the cross-sectional view of fig. 25(c) to form both wings 40, and the length of the wings (hereinafter referred to as wing length) is larger than the outer diameter of the folded balloon 3 and also larger than the nominal diameter of the balloon 3, so that it is difficult to perform the inflation treatment again with the balloon 3. That is, as shown in fig. 26, the distal tapered portion 12 divided by the wings 40, 40 hits the narrowed portion 42 of the lumen of the blood vessel 41, and the balloon catheter cannot advance any further.

FIG. 17 is a cross-sectional view showing the vicinity of the tip of the balloon catheter 1 according to embodiment 3.

As shown in fig. 1 and 17, in the balloon catheter 1 of the present embodiment, the 1 st tubular member 5 is disposed in the lumen of the 2 nd tubular member 6 to form a catheter shaft 2, and the balloon 3 is joined to the catheter shaft 2. The balloon 3 has a straight tube portion 11, distal and proximal tapered portions 12, 13, and distal and proximal sleeve portions 14, 15. The straight tube portion 11 is tubular and expands or contracts by internal pressure adjustment. The tapered portions 12 and 13 are adjacent to both ends of the straight tube portion 11 and gradually decrease in diameter. The sleeve portions 14, 15 are adjacent to both ends of the tapered portions 12, 13, and are joined to the outer peripheral surface of the 1 st tubular member 5 and the distal end of the 2 nd tubular member 6, respectively.

The outer peripheral surface of the distal end of the 2 nd tubular member 6 is reduced in diameter in view of pressure resistance, and the proximal-side sleeve portion 15 is fitted over the reduced diameter portion. Thus, the step generated after the two are jointed can be reduced. Further, a filling lumen 8 is formed between the outer peripheral surface of the 1 st tubular member 5 and the inner peripheral surface of the 2 nd tubular member 6, and a pressure fluid such as a physiological saline or a contrast medium introduced to apply an internal pressure to the balloon 3 passes through the filling lumen 8. The guidewire passes through the guidewire lumen 7 of the first tubular member 5 (1 st). A manifold 4 is connected to the proximal end of the catheter shaft, and the manifold 4 is provided with openings 9 and 10 communicating with the guidewire lumen 7 and the filling lumen 8.

The distal-side sleeve part 14 is formed by shifting a part 43 of the start position of the adjacent taper part by a predetermined distance (Ld) toward the distal side in the longitudinal direction, and specifically is formed as follows: the taper start position along the inner periphery of the distal end of the distal-side tapered portion 12 gradually shifts in the circumferential direction toward the distal side from the proximal-most taper start position 44 to the distal-most taper start position 43. In this case, the longitudinal distance between the proximal-most taper start positions 43 and 44 and the distal-most taper start positions is Ld as shown in the drawing. Fig. 18 is a cross-sectional view of the straight tube portion 11 when the balloon 3 is flapped. As shown in the figure, both wings 40, 40 are formed around the 1 st tubular member 5 for passing a guide wire in the straight tube portion 11 of the balloon 3, and the wings 40, 40 are generated with the taper start positions 43, 44 on the most proximal side and the most distal side as starting points. Thus, the positions of the wings 40, 40 can be controlled, and the distal tapered portion 12at the time of wing generation is separated by the wings 40, 40 but is displaced from each other in the longitudinal direction to form 2 steps, and does not form a steep step, so that the resistance can be greatly reduced when the balloon having the wings is passed through calcification or a lesion site where the stent is to be placed. In order to fully exhibit the above-mentioned effects, Ld should be in the range of 0.3mm to 10.0mm, preferably in the range of 0.5mm to 8 mm.

The straight tube portion 11 is a portion extending from the end position of the distal tapered portion 12 to the end position of the proximal tapered portion 13, and is basically a portion for expanding a lesion. Since the taper start position 43 of the distal tapered portion 12 is shifted toward the distal side and the corresponding taper end position is also shifted toward the distal side, the length of the straight tube portion 11 in the longitudinal direction is not constant but gradually changes in the circumferential direction. Further, the shortest narrow portion of the coronary artery to be treated by the PTCA balloon catheter is about 8.0mm in length, and the other lumen of the blood vessel to be treated by the PTA balloon catheter has a narrow portion as long as 80.0mm such as the subclavian vein, and in order to cope with these various lesion sites, the length of the straight tube portion 11 in the longitudinal direction is preferably in the range of 8.0mm to 80.0mm in the shortest portion.

The balloon 3 is preferably manufactured by blow molding in order to have sufficient strength against the internal pressure introduced during expansion. Specifically, a tubular blank having a predetermined inner diameter and outer diameter is first produced by extrusion molding, the blank is axially stretched to a length of 2 to 7 times at room temperature, and then both axially outer side portions of the portion to be formed into a straight tube portion, that is, the portion to be formed into a tapered portion and a sleeve portion are axially stretched while locally heating the portions. Thus, the tapered portion and the sleeve portion after molding can be sufficiently thinned.

In order to have a predetermined length, a preform blank is transferred into a cavity of a blow molding die, the die is closed, compressed air is blown into the interior of the die to expand the blank into a cavity shape, and the straight tube portion 11, tapered portions 12, 13 and sleeve portions 14, 15 of the balloon are formed. The shape of the cavity is preferably slightly larger than the shape of the balloon 3 of the molded article. In addition, in order to stabilize the shape and size of the balloon, heat fixing treatment may be performed as necessary. The resin material of the blank may be one or a mixture of 2 or more of polyethylene terephthalate (PET), polyethylene, polyvinyl acetate, ionomer, polyvinyl chloride, polyamide (nylon 66, nylon 12, etc.), polyamide thermoplastic elastomer, polyester thermoplastic elastomer, polyurethane thermoplastic elastomer, etc. Further, a blank having a multilayer structure in which these resins are combined may be prepared. In the invention 3, the production conditions and materials for the balloon are not limited at all, and for example, the production conditions and materials described in Japanese patent laid-open Nos. 3-57462, 3-57463 and 3-37949 may be adopted.

After the blow molding, in order to more accurately reduce the thickness of the distal-side and proximal-side jacket tubular portions 14, 15, the straight tubular portion 11 and the tapered portions 12, 13 may be fixed by a metal mold, and only the distal-side jacket tubular portion 14 or the proximal-side jacket tubular portion 15 may be stretched and extended. Alternatively, the sleeve portion may be subjected to grinding such as centerless grinding in order to further reduce the thickness.

Next, a 2 nd embodiment of the balloon catheter of the 3 rd invention will be described. FIG. 19 is a sectional view showing the vicinity of the tip end of the present embodiment.

The basic structure of the balloon catheter 1 of the present embodiment is the same as that of embodiment 1 of the above-described invention 3. The components having the same reference numerals as those in embodiment 1 have the same structure. The detailed description thereof will be omitted.

In the present embodiment, the inclination angle of the distal tapered portion 12 with respect to the longitudinal direction is gradually changed. Specifically, the distal tapered portion 12 has a shape as shown in the figure, and the inclination angle thereof gradually changes from a minimum value (θ 2) to a maximum value (θ 1) in the circumferential direction. Therefore, as shown in the cross-sectional view of the straight tube portion 11 in fig. 20, when the fins are generated, even if the fins 40, 40 are generated around the 1 st tubular member 5, the fins 40, 40 are generated from positions corresponding to the maximum value (θ 1) and the minimum value (θ 2) of the inclination angle. Thus, the positions of the wings 40, 40 can be controlled, and the distal tapered portion 12at the time of wing generation is not formed as a sharp step although it is divided by the wings 40, so that the resistance can be greatly reduced when the balloon having the wings is calcified or the stent is placed in a lesion site. In order to sufficiently reduce the resistance, the angle difference (θ 1- θ 2) between the maximum value and the minimum value of the inclination angle is in the range of 2 ° to 30 °, preferably in the range of 5 ° to 25 °.

The straight tube portion 11 is a portion extending from the end position of the distal tapered portion 12 to the end position of the proximal tapered portion 13, and is basically a portion for expanding a lesion. In this embodiment, since the inclination angle of the distal tapered portion 12 changes, the end position of the corresponding distal tapered portion 12 is also shifted in the longitudinal direction, and the longitudinal length of the straight tube portion 11 changes in the circumferential direction. The length of the straight tube portion 11 in the longitudinal direction is preferably in the range of 8.0mm to 80.0mm in the shortest portion so as to correspond to various lesion sites for the same reason as in embodiment 1.

In the above embodiments, the structure of the distal-side sleeve portion has been mainly explained, but in the 3 rd invention, the proximal-side sleeve portion may also have the same structure as that of the 2 nd tubular member. In this case, since the resistance when the balloon catheter is retracted can be reduced, damage to the vascular membrane and the like can be reduced, and the risk of postoperative complications can be reduced.

By combining the above-described embodiment 1 with embodiment 2, a better balloon catheter can be obtained by adjusting the displacement distance of the taper start position and the difference between the maximum inclination angle and the minimum inclination angle of the tapered portion. As will be apparent to one of ordinary skill in the art.

In the above embodiment, the coaxial type catheter is explained, but the 3 rd invention is also applicable to balloon catheters other than the coaxial type. For example, the present invention is also applicable to a balloon catheter having a plurality of shafts as described in Japanese patent application laid-open No. 7-132147. The invention 3 can be applied to various balloon catheters such as a through-wire type and a monorail type depending on the application.

As is apparent to those of ordinary skill in the art, the invention 3 represented by the above-described embodiment is applicable not only to PTCA balloon catheters for coronary artery therapy but also to peripheral vessels other than coronary arteries and to dialysis arteriovenous fistulas. In addition, the balloon is also applicable to all internal cavities in the body, through which the balloon cannot easily pass.

Specific examples and comparative examples of invention 3 will be described in detail below, but the following examples do not limit invention 3.

(example 10)

As shown in fig. 17, the balloon catheter 1 according to example 1 was produced. The balloon 3 is produced in the following order. A preform (inner diameter: 0.60mm, outer diameter: 1.03mm) was stretched at room temperature in the longitudinal direction by 3 times, and the resin material of the preform was "Hytrel" (manufactured by DuPont, Shore hardness: 72D). Subsequently, the outer 3cm portions in the axial direction of the central portion having a length of about 13mm were subjected to local heating (temperature 90 ℃) while the outer 3cm portions were further extended in the axial direction by 2 times, thereby preparing a preform. Then, the blank is transferred into a cavity of a blow mold, one end of the cavity is closed, and a high-pressure air source is connected to the other end. Then, the mold was closed, heated to about 90 ℃ and 280psi of air was blown into the blank to form a balloon having a nominal diameter (balloon diameter when a nominal pressure of 6atm was applied) of 3.0 mm.

As shown in FIG. 21, each dimension of the balloon 3 is such that the length of the straight tube portion 11 in the longitudinal direction is 18.0mm, the thickness thereof is 0.02mm, the inner diameter of the distal-side sleeve portion 14 is 0.57mm, the outer diameter thereof is 0.7mm, the difference (Ld) between the taper start positions 43 and 44 on the most distal side and the most proximal side of the sleeve portion is 3.0mm, the minimum length of the sleeve portion is 2.0mm, the length of the distal-side tapered portion 12 in the longitudinal direction is 4.5mm, the length of the proximal-side tapered portion 13 in the longitudinal direction is 4.1mm, the length of the proximal-side sleeve portion 15 in the proximal direction is 3.0mm, the inner diameter thereof is 0.89mm, and the outer diameter thereof is 0.99 mm.

The balloon 3 is joined to a catheter shaft to form a balloon catheter of the present embodiment.

Comparative example 10

A balloon catheter of this comparative example was produced in the same manner as in example 10, except that the dimensions and shapes of the respective parts of the balloon were set as in fig. 22. As shown in fig. 22, the balloon 3 of the present comparative example has the following dimensions: the straight tube portion 11 has a length in the longitudinal direction of 18.0mm and a wall thickness of 0.02mm, the distal side sleeve portion 14 has an inner diameter of 0.57mm and an outer diameter of 0.7mm and a length of 2.0mm, the distal side tapered portion 12 has a length in the longitudinal direction of 4.5mm, the proximal side tapered portion 13 has a length in the longitudinal direction of 4.1mm, the proximal side sleeve portion 15 has a length of 3.0mm and an inner diameter of 0.89mm, and the outer diameter thereof is 0.99 mm. The distal-side sleeve portion 14 has a constant inclination angle with respect to the longitudinal direction in the circumferential direction (θ 1 — θ 2).

(evaluation method)

The experimental system shown in fig. 23 was used. That is, a metal tube 46 having an inner diameter of 3.0mm and a length of 5cm in the longitudinal direction was coaxially butted against the distal end surface of a polyurethane tube 45 having an inner diameter of 3.5mm and a length of 20cm in the longitudinal direction, and an experimental environment of a vascular lumen having a stenotic portion was prepared. The balloon catheter 1 in which the wings are horizontally formed is advanced along the guide wire 47 after the guide wire 47 is passed through the lumen of the tube, and when the balloon 3 passes through the boundary between the polyurethane tube 45 and the metal tube 46, the maximum value of the load cell 49 fixed to the manifold 4 by the jig 48 is recorded as a measurement value, and the balloon catheter is evaluated based on the measurement values. The inner diameter of the metal tube 46 is smaller than the length of the wings 40, 40 of the balloon 3.

(evaluation results 1)

The measurement values of the balloon catheters of example 10 and comparative example 10 using the experimental system described above were as follows, in example 10: 0.28N, comparative example 10: 0.51N. In example 10, the resistance was greatly reduced as compared with comparative example 10.

(example 11)

As shown in fig. 19, the balloon catheter according to embodiment 2 was manufactured. The balloon catheter of the present example was produced in the same manner as in example 10 above, except that the dimensions and shape of each part of the balloon were set as in fig. 24. In example 11, as shown in fig. 24, the dimensions of each part of the balloon 3 are as follows: the maximum inclination angle (θ 1) of the distal tapered portion 12 is 15 °, the minimum inclination angle (θ 2) is 8 °, the difference (θ 1- θ 2) therebetween is 7 °, the length of the straight tube portion 11 in the longitudinal direction is 18.0mm, the wall thickness is 0.02mm, the inner diameter of the distal sleeve portion 14 is 0.57mm, the outer diameter thereof is 0.7mm, the length thereof is 2.0mm, the length of the proximal sleeve portion 15 is 3.0mm, the inner diameter thereof is 0.89mm, and the outer diameter thereof is 0.99 mm.

(evaluation results 2)

The measurement values of the balloon catheters of example 11 and comparative example 10 were as described in example 11: 0.38N, comparative example 10: 0.51N. In example 11, the resistance was significantly reduced as compared with comparative example 10 (in which the taper start position of the distal-side tapered portion was the same in the circumferential direction).

Next, embodiments of the invention 4 will be described with reference to fig. 27 to 30.

Fig. 27 is a schematic view showing an example of the balloon catheter protector according to the 4 th aspect of the present invention. Fig. 27(a) is a cross-sectional view showing the balloon catheter protector according to the present embodiment, and fig. 27(b) is a right side view of the balloon catheter protector.

The balloon catheter protector 50 of the present embodiment includes a tubular protection tube portion 51 and a connector 52. The balloon catheter is inserted at its distal end into the protection tube 51. The connector 52 is fitted coaxially with a base end portion 53 of the protection tube portion 51, and is connected to a flushing fluid supply device such as a syringe. The protection tube part 51 and the connector 52 may be bonded together by an adhesive or by heat welding. In the present embodiment, the protection tube part 51 and the connector 52 are fitted, but the invention of claim 4 is not limited thereto, and the protection tube part 51 and the connector 52 may be formed integrally.

The protection tube part 51 is made of a resin such as polyolefin, fluorinated polyolefin, or the like, preferably polyethylene, polypropylene, fluorinated polyethylene, fluorinated polypropylene, fluorinated ethylene propylene copolymer, more preferably fluorinated ethylene propylene copolymer. At least, the length of the protective balloon 3 in the axial direction is usually 5.0mm to 100.0mm, preferably 7.0mm to 80.0 mm. The front end portion inner cavity 54 of the protection tube portion 51 is formed into a tapered shape having a diameter gradually increased toward the front end so as to facilitate insertion of the balloon. The inner diameter of the protective tube 51 is selected according to the outer diameter of the balloon 3 in a folded state, and is usually 0.1mm to 4.0mm, preferably 0.3mm to 2.0mm, more preferably 0.5mm to 1.2 mm. In order to facilitate the removal of the balloon catheter 1 from the protective tube 51, the inner cavity 55 may be tapered so as to gradually expand from the base end 53 toward the tip end along the entire length of the protective tube 51.

The connector 52 is mainly made of polyolefin resin such as polyethylene and polypropylene, preferably polypropylene resin, and includes a cylindrical fitting portion 56 and a connection port 57. The fitting portion 56 is fitted to the base end portion 53 of the protection tube portion 51. The connection port 57 is connectable to a flushing fluid supply device such as a syringe. An annular flange 58 is formed on the outer peripheral portion of the rear end of the connector 52. A flow passage 59 is formed in the connector 52, and the flushing fluid supplied from the connection port 57 flows through the flow passage 59 and communicates with the inner cavity 55 of the protection tube part 51. Further, as shown in fig. 27(b), luer locking projections 60, 60 are formed on the flange 58 at positions 180 degrees opposite to the center axis thereof.

Before use, as shown in fig. 28, the protector 50 for a balloon catheter having the above-described structure is inserted into the tip end portion 61 of the balloon catheter 1 (the balloon catheter 1 has the balloon 3 in a folded state to which negative pressure is applied). In order to protect the 1 st tubular member 5 (not shown) constituting the lumen of the guide wire, a protective core 62 made of steel is inserted into the 1 st tubular member 5. The protective core 62 is fixed to the front end surface of the core holding portion 63 made of resin, the core holding portion 63 is detachably fitted into the connection port 57, and a pin 64 is fixed to the rear end surface of the core holding portion 63 so that the protective core 62 can be easily removed from the inner shaft.

In the actual use of the protector of this embodiment, the protective core 62 is pulled out from the 1 st tubular member 5, and the flushing fluid supply device is connected to the connector 52. The connection here means a fixed state in which the protector 50 and the irrigation fluid supply device of the present embodiment are not detached from each other when the guidewire lumen 7 of the balloon catheter 1 is irrigated with a physiological saline solution or the like. Fig. 29 shows a state in which the tip 66 of a syringe 65 of a relatively small capacity is connected to the connector 52. The barrel tip 66 of the syringe 65, which is a flushing fluid supply device, has a tapered outer peripheral surface, and is detachably inserted into the connection port 57 by being in close contact with the tapered inner peripheral surface of the connection port 57. In this state, the flushing fluid in the syringe 65 is injected into the connection port 57, flows into the distal end opening of the guidewire lumen 7 of the balloon catheter 1 through the flow passage 59, and flushes the guidewire lumen 7. Then, the balloon catheter protector 50 is removed from the balloon catheter 1 after completion of the irrigation, and a surgery such as PTCA is performed.

In the above embodiment, the barrel tip 66 of the syringe is fitted to the connection port 57, but in other embodiments, a connection port fitted to an injection needle holding member (not shown) for holding an injection needle may be used. In this case, the inner peripheral surface of the connection port is formed into a tapered shape which is in close contact with the outer peripheral surface of the needle holding member.

Fig. 30 shows a state in which a tip 68 of a relatively large-capacity syringe 67 is connected to the connector 52 by so-called luer lock coupling. The tip 68 of the syringe 67 has an outer cylinder 69 and an inner cylinder 70 which are coaxial with each other. Double spiral projections 71, 72 are formed on the inner peripheral surface of the outer tube portion 69, and a hollow portion 73 of the inner tube portion 70 communicates with an internal space 74 of the syringe 67. The luer lock protrusion of the connector 52 is rotatably fitted along the groove between these spiral protrusions 71, 72, and the outer peripheral surface of the inner tube 70 is brought into close contact with the tapered inner peripheral surface of the connection port 57. Thus, the barrel tip 68 of the syringe 67 is attached to the connector 52. In this state, the flushing fluid in the internal space 74 of the syringe 67 is injected into the connection port 52, flows into the distal end opening of the guidewire lumen 7 of the balloon catheter 1 through the flow passage 59, and flushes the guidewire lumen 7.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, the balloon catheter of claim 1 has a good operability because the tip portion thereof is flexible, and particularly has a good ability to enter a lesion of a high-curvature portion or a lesion of high hardness.

According to the balloon catheter of the invention 2 in which the balloon is made of the polymer blend material, the 1 st polymer component has higher shore hardness than the 2 nd polymer component, and the 1 st polymer component and the 2 nd polymer component are both thermoplastic elastomers having hard segments of the same repeating unit structure and soft segments of the same repeating unit structure, so that optimization of the blend material blending ratio, which has been difficult, can be easily achieved, and the radial expansion ratio (expansion and contraction characteristic) of the balloon with respect to the expansion pressure can be maintained in a state from semi-expansion to non-expansion, and a balloon having sufficient compressive strength and flexibility can be obtained. The balloon catheter is excellent in passability and operability at a lesion site, and is very useful for medical treatment.

According to the balloon catheter of the 1 st embodiment of the 3 rd invention, at least one of the distal-side sleeve portion and the proximal-side sleeve portion has a shape in which a part of the taper start position adjacent to the sleeve portion is displaced in the longitudinal direction, the inner surface of the distal-side sleeve is joined to the outer surface of the guide wire passage tube, and the proximal-side sleeve portion is joined to the end portion of the outer tube, so that the distal-side tapered portion at the time of the formation of the wings is separated by both wings but is displaced from each other in the longitudinal direction to form 2 steps, and a steep step is not formed, so that when the balloon at which the wings are formed is passed through a calcified portion or a lesion portion of the stent, the resistance can be greatly reduced, the lumen of the blood vessel is not damaged, and the risk of pushing the stent to the distal side of the stent vessel to cause displacement of the stent is greatly reduced.

According to the balloon catheter of embodiment 2 of the 3 rd invention, since the inclination angle of the taper portion in at least one of the distal taper portion and the proximal taper portion changes in the circumferential direction, the distal taper portion when the wings are formed is separated by both wings but does not form a steep step, and therefore, as in the case of the 1 st invention, the resistance can be greatly reduced when the balloon having the wings is passed through the lesion site where calcification or stent is retained,

according to the balloon catheter protected by the protector of the invention of claim 4, since the product is shipped in a protected state by inserting the tip portion including the balloon into the interior of the protection tube portion, the tip portion including the balloon can be prevented from being bent before use, and the balloon catheter can be prevented from being inserted into the stenosis portion due to bending. In addition, the connector is connected with a fluid supplier for flushing, so that the flushing fluid flows into the guide wire lumen of the balloon catheter to flush. Thus, the guidewire lumen of the balloon catheter can be flushed without requiring troublesome work and without damaging or deforming the tip portion of the balloon catheter.

Industrial applicability

As described above, the balloon catheter of the present invention is used for treatment and operation for expanding a lesion site such as a stenosis portion or an occlusion portion of a body passage, mainly in the field of angioplasty medical treatment such as peripheral angioplasty, coronary angioplasty, and valvuloplasty.

Claims (27)

1. A balloon catheter comprising a plurality of tubular members and a balloon, wherein a 1 st tubular member is disposed so as to pass through the inside of the balloon, wherein one of the purposes of the 1 st tubular member is to pass a slidable guide wire through the inside thereof, and wherein the balloon is welded concentrically to the outer surface of the 1 st tubular member in the vicinity of the distal end of the catheter, and wherein the outermost material of the 1 st tubular member, at least the welded portion to the balloon, is made of a material having a Shore hardness lower than the Shore hardness of the material of the balloon.

2. A balloon catheter according to claim 1, wherein the fixation of the balloon to the 1 st tubular member is carried out by thermal fusion in the vicinity of the distal end of the catheter by thermally fusing a material compatible with the balloon and the 1 st tubular member or a material chemically reactive with the balloon and the 1 st tubular member as a direct fixation layer or as at least one layer obtained by laminating the fixation portion, wherein the shore hardness of the material constituting the layer adjacent to the balloon is lower than the shore hardness of the material constituting the balloon.

3. A balloon catheter according to claim 2 wherein said balloon is formed of a polyester elastomer material and at least the outermost of said 1 st tubular member to which said balloon is bonded is formed of a polyester elastomer material.

4. A balloon catheter according to claim 3 wherein said balloon is formed of a polyester elastomer material and the material forming said 1 st tubular member adjacent said balloon is formed of a polyester elastomer material.

5. A balloon catheter according to claim 4 wherein said polyester elastomer material is a polyester elastomer having hard and soft segment components in the molecule and the proportion of soft segment is greater than 13%.

6. A balloon catheter according to claim 2 wherein said balloon is formed of a polyamide elastomer material and at least the outermost of said 1 st tubular member portions to which said balloon is bonded is formed of a polyamide elastomer material.

7. A balloon catheter according to claim 6 wherein said balloon is formed of a polyamide elastomer material and the material forming said 1 st tubular member adjacent said balloon is formed of a polyamide elastomer material.

8. A balloon catheter according to claim 7, wherein said polyester elastomer material or said polyamide elastomer material has hard and soft segment components in a molecule, and the ratio of the soft segment component of the material constituting the balloon is adjusted to be smaller than the ratio of the soft segment component of the material constituting the outermost layer of the 1 st tubular member or the material constituting the layer adjacent to the balloon.

9. A balloon catheter according to claim 8 wherein said polyamide elastomer material is a polyamide elastomer having hard and soft segment components in the molecule, the soft segment component being greater than 14%.

10. A balloon catheter according to claim 1, wherein the innermost surface of said 1 st tubular member is formed of high density polyethylene.

11. A balloon catheter according to claim 10 wherein said 1 st tubular member is of a multilayer construction of 2 or more layers, the outermost of which is formed of a polyamide elastomer or a polyester elastomer and the innermost of which is formed of high density polyethylene, and wherein there is one or more adhesive layers between the outermost layer and the innermost layer.

12. A balloon catheter according to claim 1, wherein said balloon is made of a thermoplastic elastomer having a hard segment and a soft segment, i.e., a polymer blend material of a 1 st polymer component and a 2 nd polymer component, said 1 st polymer component has a higher shore hardness than said 2 nd polymer component, and both of said 1 st polymer component and said 2 nd polymer component are thermoplastic elastomers having a hard segment of the same repeating unit structure and a soft segment of the same repeating unit structure.

13. A balloon catheter according to claim 12 wherein said 1 st polymer component has a shore hardness of at least D70 and said 2 nd polymer component has a shore hardness of less than D70.

14. A balloon catheter according to claim 12 wherein said 1 st polymer component and said 2 nd polymer component are polyester elastomers.

15. A balloon catheter according to claim 12 wherein said 1 st polymer component and said 2 nd polymer component are polyamide elastomers.

16. A balloon catheter according to claim 12, wherein the 1 st polymer component (a) and the 2 nd polymer component (B) are blended in a weight ratio of (a)/(B) of 98/2 to 10/90.

17. A balloon catheter according to claim 1, wherein said 1 st tubular member is disposed through the interior of the balloon, and the balloon is welded concentrically to the outer surface of the 1 st tubular member in the vicinity of the distal end of the catheter; the 2 nd tubular member constituting the outer surface of the catheter is made of a material weldable to the balloon, and is disposed in a state of connection to the proximal side of the balloon.

18. A balloon catheter according to claim 17, wherein said balloon has a straight tube portion, proximal and distal tapered portions adjacent to both ends of the straight tube and gradually reducing in diameter, proximal and distal sleeve portions adjacent to both ends of the tapered portions; at least one of the distal sleeve portion and the proximal sleeve portion has a shape in which a part of a start position of the taper portion adjacent to the sleeve portion is displaced in the axial direction, an inner surface of the distal sleeve portion is joined to an outer surface of the 1 st tubular member, and the proximal sleeve portion is joined to an end of the 2 nd tubular member.

19. A balloon catheter according to claim 18, wherein the displacement of the start position of the taper portion adjacent to the sleeve portion in the longitudinal direction is adjustable within a range of 0.3mm to 10.0 mm.

20. A balloon catheter according to claim 17, wherein said balloon has a straight tube portion, proximal and distal tapered portions adjacent to both ends of the straight tube and gradually reducing in diameter, proximal and distal sleeve portions adjacent to both ends of the tapered portions; the inclination angle of the taper portion in at least one of the distal taper portion and the proximal taper portion is changed in the circumferential direction, the inner surface of the distal sleeve is joined to the outer surface of the 1 st tubular member, and the proximal sleeve portion is joined to the end of the 2 nd tubular member.

21. A balloon catheter according to claim 20, wherein the difference between the maximum value and the minimum value of said inclination angle is adjustable within the range of 2 ° to 30 °.

22. A balloon catheter according to claim 18, wherein the length of the straight tube portion in the longitudinal direction is adjustable within a range of 8mm to 80 mm.

23. A balloon catheter according to claim 1, wherein said balloon catheter is a quick-change balloon catheter in which the proximal end of the 1 st tubular member is opened halfway along the catheter shaft.

24. A balloon catheter according to claim 1, wherein the balloon catheter is provided with a protective sheath for protecting a tip portion including the balloon, and a connector detachably connected to the flushing fluid supply unit.

25. A balloon catheter according to claim 24, wherein the connector is provided with a connection port into which a tip of a syringe as the supply unit for the flushing fluid is detachably inserted.

26. A balloon catheter according to claim 24, wherein said connector is provided with a luer lock coupling for connection to a supply of irrigation fluid.

27. A balloon catheter according to claim 24, wherein said connector is provided with a connection port into which the needle holder is removably inserted.