Patent Description:
Conventionally, percutaneous angioplasty has been widely utilized in dilation treatment for a narrow or occluded part of a vascular lumen for the purpose of recovering or improving blood flow in a coronary artery or a peripheral blood vessel. An example of a balloon catheter used in percutaneous angioplasty will be given below. In a common structure of the balloon catheter, a balloon that can be freely inflated and deflated by adjusting the internal pressure is joined to the end of a shaft, and a lumen into which a guide wire is inserted (guide wire lumen) and a lumen through which pressure fluid for adjusting the internal pressure of the balloon is supplied (inflation lumen) are provided inside the shaft along the longitudinal direction of the shaft. Further, a balloon catheter includes an over-the-wire balloon catheter in which the guide wire lumen extends throughout the entire length thereof, and a rapid exchange balloon catheter in which the guide wire lumen extends only in the distal part of the catheter in order to allow easy exchange of the balloon catheter.

A common surgical case of PTCA using such a balloon catheter is as follows. First, a guide catheter is inserted from a puncture part in a femoral artery, a brachial artery, a radial artery or the like so as to pass through the main artery, and the distal end of the guide catheter is positioned on an entrance of a coronary artery. Then, a guide wire which has been inserted into the guide wire lumen is advanced beyond a narrow part of the coronary artery, and a balloon catheter is inserted along the guide wire so that the position of a balloon is matched with the position of the narrow part. Then, pressure fluid is supplied to the balloon through the inflation lumen using a device such as an indeflator to inflate the balloon, thereby performing dilation treatment on the narrow part. After the dilation treatment is performed on the narrow part, the balloon is deflated by reducing the pressure inside thereof and removed from the body, thereby finishing the PTCA.

In balloon catheters used in PTCA, there is a classification called a perfusion balloon catheter in addition to a general balloon catheter. In a perfusion balloon catheter, blood can be perfused from the proximal side of a balloon to the distal side thereof with the balloon inflated inside a blood vessel in a narrow part or the like. A perfusion balloon catheter generally has a proximal side perfusion port on a shaft at the proximal side of the proximal end of a balloon and a distal side perfusion port at the distal side of the distal end of the balloon, and can perfuse blood through the perfusion ports and a lumen which perfuses blood inside thereof (also referred to as a perfusion lumen). The perfusion balloon catheter is disclosed in Patent Documents <NUM> and <NUM>. Since an ischemic state of a blood vessel at a more distal position than the balloon can be prevented or minimized by performing blood perfusion even when the balloon is in an inflated state, the balloon inflation can be maintained for a long period of time.

As disclosed in Patent Documents <NUM> and <NUM>, the perfusion lumen is generally formed to pass through an inside tube which passes through the inside of the balloon. In order to perfuse a larger amount of blood, a perfusion lumen having a larger cross sectional area is advantageous. Therefore, a perfusion balloon catheter has a larger inside tube than a general balloon catheter. On the other hand, since pressure is applied to the inside tube which passes through the inside of the balloon from the outside thereof when inflating the balloon, the larger the inside tube is, the larger stress applied to the outer wall of the inside tube becomes. As a result, the inside tube tends to be easily crushed or kinked. Therefore, an inside tube of a perfusion balloon catheter is made more rigid than that of a general balloon catheter or reinforced with metal.

Recently, a polyamide or polyurethane thermoplastic polymer has often been used as the material for a balloon of a balloon catheter used in PTCAin view of flexibility, strength, formability, processability and the like. Further, when the inside tube of the balloon catheter is formed of a material that is different from the material of the balloon, it is necessary to bond the inside tube and the balloon to each other with adhesive, and the bonded part thereby disadvantageously becomes rigid. Therefore, it has become common that at least an outer layer of the inside tube is formed of the same kind of material as that of the balloon, and the outer layer is heat-welded to the balloon. Thus, it is necessary that the inside tube of the perfusion balloon catheter be reinforced with metal or the like, and at least the outer layer of the inside tube be formed of a thermoplastic polymer such as a polyamide material.

Patent Documents <NUM> and <NUM> disclose a method for reinforcing a catheter shaft with metal using a coil structure or a braid structure. Both of Patent Documents <NUM> and <NUM> disclose a method in which a reinforcing metal (a reinforcing coil in Patent Document <NUM> and a metal braid in Patent Document <NUM>) is applied around an inner layer tube which is formed of a fluorine-containing ethylene polymer having excellent wettability such as polytetrafluoroethylene, and an outer layer tube which is formed of a polyamide material or the like is coated thereon. Recently, a thermoplastic polymer such as a polyamide material has often been used as the material of a catheter shaft in view of flexibility, strength, and processability. However, since it is generally necessary, when forming a composite tube, to previously insert a lumen forming core member into an inner layer tube and remove the core member therefrom after forming the tube, it has been necessary to use a material having excellent wettability in the inner layer tube. For example, when a thermoplastic polymer is used in the inner layer, there is caused a problem such that the inner layer is stuck to the surface of the lumen forming core member, and the lumen forming core member cannot therefore be pulled out. On the other hand, a material having excellent wettability such as a fluorine-containing ethylene polymer has a low affinity for a polyamide material. Therefore, the inner layer and the outer layer are delaminated from each other in such a configuration. If the inner layer is delaminated from the outer layer inside the body, the inner layer may remain therein. In some cases, the remaining inner layer may threaten patient's life. In Patent Documents <NUM> and <NUM>, chemical etching is performed on or a reactive functional group is introduced into the outer surface of the inner layer tube formed of a fluorine-containing ethylene polymer or the like to thereby improve the adhesiveness between the inner layer tube and the outer layer tube. However, it is necessary to introduce a large-scale apparatus to perform the surface processing, and there is a limit to improving the adhesiveness by the surface processing. Therefore, the possibility of delamination of the inner layer from the outer layer could not be completely eliminated. Especially in a balloon catheter, a balloon is inflated by pressure so as to be stretched in the radial direction and the axial direction. Since an inside tube is also stretched in the axial direction along with the extension of the balloon, delamination of an inner layer disadvantageously occurs more easily. <CIT> discloses a catheter for use in an emboli containment system. The catheter has a tubular body with a metallic braid construction. Two lumen extend through the tubular body, the lumen being in a side-by-side configuration. One of the lumen functions as an inflation lumen, and is in fluid communication with an inflatable balloon mounted on the distal end of the catheter. The second lumen is adapted to receive other therapeutic catheters which comprise the emboli containment system. <CIT> discloses a medical tube which is flexible and achieves good kink resistant properties and high tensile strength at the same time. Even when connected to another tube, the medical tube maintains the above-mentioned kink resistant properties and tensile strength. A medical tube is provided with at least one coil layer, a first outer layer provided outside the coil layer and a second outer layer provided outside the first outer layer. The melting point of the material which forms the second outer layer is lower than the melting point of the material forming the first outer layer. The outer surface of the coil layer and the inner surface of the first outer layer are in contact with and affixed to each other in a slidable state. Patent Documents <NUM> to <NUM> disclose further prior art.

In view of the above problems, an object of the present invention is to provide a balloon catheter having excellent productivity, the balloon catheter being capable of, in a balloon inside tube of the balloon catheter having an inner layer, an outer layer, and a support body, preventing delamination of the inner layer when a guide wire is inserted into the balloon inside tube and also easily removing a lumen forming core member after forming the balloon inside tube during a production process when a balloon is heat-welded to form an end part of the balloon.

Further, another object of the present invention is to provide a method for efficiently producing the balloon catheter provided with the balloon inside tube.

As a result of intensive studies to solve the above problems, the present inventor has focused on the melting points of the inner and the outer layers forming the balloon inside tube.

The above-mentioned problems are solved by a balloon catheter according to claim <NUM>.

The above-mentioned problems are further solved by a method for producing a balloon catheter according to claim <NUM>. Further advantageous embodiments are disclosed in the dependent claims.

According to the balloon catheter of the present invention, the balloon, and the inner and outer layers forming the balloon inside tube are heat-welded to each other. Therefore, delamination of the inner layer of the balloon inside tube can be prevented.

In an advantageous embodiment of the present invention, since the heat-welding is performed at a temperature that is equal to or higher than the melting point of the thermoplastic polymer forming the outer layer of the balloon inside tube as well as lower than the melting point of the thermoplastic polymer forming the inner layer, the outer layer is melted without melting the inner layer.

Therefore, the lumen forming core member can be easily removed after forming the balloon inside tube which is formed of thermoplastic polymers, and delamination of the inner layer does not easily occur even when a guide wire makes contact with the inner layer such as a case where the guide wire is inserted into and removed from the inner lumen of the balloon inside tube.

In the present invention, the balloon has a distal side sleeve at the distal side thereof, and the distal side sleeve is heat-welded to a distal part of the balloon inside tube at a temperature equal to or higher than the melting point of the thermoplastic polymer forming the inner layer of the balloon inside tube. Therefore, the distal side sleeve and the outer and inner layers of the balloon inside tube are integrated with each other, thereby making it possible to further suppress the delamination of the inner layer of the balloon inside tube.

In an advantageous embodiment of the present invention, the balloon has a proximal side sleeve at the proximal side thereof, and the proximal side sleeve is heat-welded to a proximal part of the balloon inside tube at a temperature equal to or higher than the melting point of the thermoplastic polymer forming the inner layer of the balloon inside tube. Therefore, the sleeves of the balloon can be firmly welded to the balloon inside tube.

In an advantageous embodiment of the present invention, each of the thermoplastic polymers is polyamide or a polyamide elastomer. Therefore, the balloon catheter has adequate flexibility, strength, and processability.

Further, in an advantageous embodiment of the present invention, the Shore D hardness of the inner layer is in the range of 63D to 74D. Therefore, when the balloon and the balloon inside tube are heat-welded to each other, more firm welding at the interfaces between the inner layer, the outer layer, and the balloon tends to be achieved.

In an advantageous embodiment of the present invention, the shore D hardness of the outer layer is in the range of 40D to 55D. Therefore, the balloon catheter has more adequate flexibility.

In an advantageous embodiment of the present invention, the support body is embedded in the outer layer, extends at least over a part of the balloon inside tube, the part being positioned within the inner lumen of the balloon, and extends throughout the entire circumferential direction of the balloon inside tube. Therefore, it is possible to improve the pressing performance and the buckling strength in the radial direction of the balloon catheter.

In an advantageous embodiment of the present invention, the support body is a coil-shaped support body. Therefore, it is possible to improve the buckling strength in the radial direction of the balloon portion and impart pliability to the balloon inside tube.

In an advantageous embodiment of the present invention, the coil-shaped body is formed of a rectangular wire. Therefore, improvement of the pressing performance in the axial direction of the balloon catheter can be expected.

In an advantageous embodiment of the present invention, the coil-shaped support body is formed of a round wire. Therefore, improvement of the pliability of the balloon catheter can be expected.

In an advantageous embodiment of the present invention, the balloon catheter includes a radiopaque marker located within the balloon inside tube. Therefore, it is possible to confirm the position of the balloon inserted into the body.

In an advantageous embodiment of the present invention, the radiopaque marker is located at more inner position in the radial direction than the support body. Therefore, it is possible to reduce deviation of the support body in the axial direction when forming the balloon inside tube.

Further, it is preferred that the balloon inside tube be connected to a distal end of a distal side shaft, a proximal side shaft be connected to a proximal end of the distal side shaft, and a hub be attached to a proximal part of the proximal side shaft.

In advantageous embodiment of the present invention, the balloon catheter is a perfusion balloon catheter, and an inner lumen of the balloon inside tube forms a perfusion lumen. Therefore, the perfusion lumen and the guide wire lumen can be formed as a single lumen.

Hereinbelow, various embodiments of a balloon catheter according to the present invention will be described in detail with reference to the drawings. The balloon catheter according to the present invention can be applied, without limitation, to a general balloon catheter, a perfusion balloon catheter, a drug-releasing balloon catheter and the like. However, since application to a perfusion balloon catheter is particularly useful, a perfusion balloon catheter will be described below as a main embodiment.

As shown in <FIG>, a balloon catheter A of the present invention includes a distal side shaft <NUM>, a balloon <NUM> which is attached to a distal part of the distal side shaft <NUM>, a proximal side shaft <NUM>, and a hub <NUM> which is attached to a proximal part of the proximal side shaft <NUM>. Although the embodiments of the present invention will be described on the basis of the rapid exchange balloon catheter as shown in <FIG>, the preset invention can also be applied to an over-the-wire balloon catheter, an on-the-wire balloon catheter provided with a guide wire, and the like.

In the case of the rapid exchange balloon catheter, the proximal side shaft <NUM> is required to be a rigid shaft. Therefore, the proximal side shaft <NUM> can be a metal tube, or a core wire can be provided inside the shaft. As shown in <FIG>, a proximal side guide wire port <NUM> can be provided near the junction between the proximal side shaft <NUM> and the distal side shaft <NUM>, and a distal side guide wire port <NUM> can be provided at the tip of the catheter. A guide wire lumen through which a guide wire passes can be provided from the proximal side guide wire port <NUM> up to the distal side guide wire port <NUM>.

Further, in order to inflate the balloon <NUM>, an inflation lumen <NUM> which communicates with the inside of the balloon <NUM> can be provided in parallel to the guide wire lumen <NUM> from an inflation port <NUM> at the proximal end of the hub <NUM> through the inside of the proximal side shaft <NUM> and the distal side shaft <NUM>. The guide wire lumen <NUM> and the inflation lumen <NUM> may form a coaxial configuration (double-tube structure) as shown in <FIG>, or may also form a biaxial configuration (parallel structure) as shown in <FIG> and <FIG>. For example, in the rapid exchange balloon catheter A as shown in <FIG>, since a guide wire is inserted from the proximal side guide wire port <NUM>, the guide wire lumen <NUM> extends only within the distal side shaft <NUM>. Therefore, only the distal side shaft <NUM> can be formed into a coaxial or biaxial shaft. As shown in <FIG>, the guide wire lumen <NUM> of the coaxial distal side shaft <NUM> is formed by an inside tube <NUM>.

Generally, the perfusion balloon catheter A is advanced into the blood vessel <NUM> along a guide wire <NUM> as shown in <FIG>. When the blood vessel <NUM> is a coronary artery, the perfusion balloon catheter A is inserted into the blood vessel <NUM> from the proximal side of the perfusion balloon catheter A toward the distal side thereof along a flowing direction <NUM> of blood <NUM>. Then, as shown in <FIG>, in order for the perfusion balloon catheter A to have a function to perfuse the blood <NUM> from the proximal side of the balloon <NUM> toward the distal side thereof when the balloon <NUM> is inflated inside the blood vessel <NUM>, proximal side perfusion ports <NUM> can be provided on the distal side shaft <NUM> at more proximal positions than the balloon <NUM>, and distal side perfusion ports <NUM> can be provided on the distal side shaft <NUM> at more distal positions than the balloon <NUM> so that the blood <NUM> flows inside the blood vessel <NUM> regardless of the existence of the balloon <NUM>.

The balloon catheter A of the present invention has the same configuration as a perfusion balloon catheter as described above. In particular, a perfusion lumen <NUM> for passing blood therethrough is formed by the balloon inside tube <NUM> which passes through the inner lumen of the balloon <NUM>. For example, as shown in <FIG>, the proximal end of the balloon inside tube <NUM> is brought to butt against and bonded to a distal end 4X of the distal side shaft <NUM>, and the perfusion lumen <NUM> is provided so that blood passes from the proximal side perfusion ports <NUM> formed on the distal side shaft <NUM> toward the distal side perfusion ports <NUM> formed on the balloon inside tube <NUM>. The perfusion lumen <NUM> and the guide wire lumen <NUM> can be formed as a single lumen. When the perfusion lumen <NUM> and the guide wire lumen <NUM> are formed as a single lumen in this manner, the proximal side perfusion ports <NUM> are only required to be formed on the wall of the distal side shaft <NUM> so as to communicate with the guide wire lumen <NUM> of the distal side shaft <NUM>.

Further, in order to increase the perfusion amount of the blood <NUM> even when the balloon <NUM> is in an inflated state as shown in <FIG>, an additional lumen other than the guide wire lumen <NUM> can also be provided in the balloon inside tube <NUM> as in a balloon catheter A' shown in <FIG>. The number of lumens provided in the balloon inside tube <NUM> may, for example, be two as in the balloon catheter A' shown in <FIG>, or three or more as necessary. When multiple lumens are provided in this manner, the cross-sectional shape of the balloon inside tube <NUM> in the radial direction may, for example, have a biaxial structure in which the guide wire lumen and the perfusion lumen are arranged in parallel to each other. However, a coaxial structure and other structures are also possible.

In the present invention, when forming the proximal side perfusion ports <NUM>, a part of the distal side shaft <NUM>, the part being positioned immediately near the balloon <NUM> at the proximal side thereof, preferably has a biaxial structure that has at least the inflation lumen <NUM> and the guide wire lumen <NUM> in view of easy processing. The inflation lumen <NUM> of the biaxial distal side shaft <NUM> communicates with the inner lumen of the balloon <NUM> so that the balloon <NUM> can be inflated and deflated in accordance with a conventional method. On the other hand, the guide wire lumen <NUM> communicates with the inner lumen of the balloon inside tube <NUM>.

Each of the perfusion ports <NUM> and <NUM> may have any size as long as it is sufficient for the perfusion of the blood <NUM>. Further, each of the number of the perfusion ports <NUM> and the number of the perfusion ports <NUM> may be one, or may also be two or more. However, given the possibility of blockage of the perfusion ports <NUM> and <NUM> due to a thrombus or the like, each of the number of the perfusion ports <NUM> and the number of the perfusion ports <NUM> is preferably two or more in view of safety. The distal side perfusion ports <NUM> may be disposed on a straight line, or may also be disposed by shifting one another in the circumferential direction, and the proximal side perfusion ports <NUM> may be disposed on a straight line, or may also be disposed by shifting one another in the circumferential direction as shown in <FIG>. Further, spaces between the distal side perfusion ports <NUM> or between the proximal side perfusion ports <NUM> may be uniform, or may also be changed such that the spaces are made gradually smaller toward the distal side of the catheter. Each of the perfusion ports <NUM> and <NUM> preferably has a circular shape in view of easy processing. However, each of the perfusion ports <NUM> and <NUM> may be formed into an oval shape or other shapes depending on the circumstances.

The perfusion lumen <NUM> which connects the perfusion ports <NUM> and <NUM> to each other is formed by the balloon inside tube <NUM> which passes through the inner lumen of the balloon <NUM>. The perfusion lumen <NUM> may be formed as a single lumen together with the guide wire lumen <NUM> as shown in <FIG>, or may also be formed as a different lumen from the guide wire lumen <NUM> of the balloon inside tube <NUM> as shown in <FIG>.

As shown in <FIG>, the balloon inside tube <NUM> includes an inner layer <NUM>, an outer layer <NUM>, and a support body <NUM>. A radiopaque marker <NUM> can be provided in the balloon inside tube <NUM> as necessary.

In the present invention, the inner layer <NUM> indicates a layer that forms the inner lumen formed in the balloon inside tube <NUM>, and the outer layer <NUM> indicates a layer that covers the outer periphery of the inner layer <NUM>.

Further, in the present invention, the balloon inside tube <NUM> is formed by heat-welding the outer layer <NUM> to the inner layer <NUM> and the support body <NUM> at a temperature that is equal to or higher than the melting point of a thermoplastic polymer that forms the outer layer <NUM> as well as lower than the melting point of a thermoplastic polymer that forms the inner layer <NUM>. Therefore, sleeves of the balloon <NUM> can be firmly welded to the balloon inside tube <NUM>. Further, even when a guide wire makes contact with the inner layer <NUM> such as a case where the guide wire is inserted into or removed from the inner lumen of the balloon inside tube <NUM>, delamination of the inner layer <NUM> is not likely to occur.

The inner layer <NUM> of the balloon inside tube <NUM> is only required to be formed of a thermoplastic polymer that can be heat-welded to the balloon <NUM> and the outer layer <NUM> of the balloon inside tube <NUM> as well as has a higher melting point than a thermoplastic polymer that forms the outer layer <NUM>. Since the inner layer <NUM> is formed of a thermoplastic polymer that can be heat-welded to the outer layer <NUM> of the balloon inside tube <NUM> and is the same kind of thermoplastic polymer as the material of the outer layer <NUM>, the inner layer <NUM> and the outer layer <NUM> are not easily delaminated from each other.

Further, the thermoplastic polymer forming the inner layer <NUM> is heat-welded to a distal side sleeve <NUM> and can be heat-welded to a proximal side sleeve <NUM> of the balloon <NUM>. Therefore, when the balloon <NUM> and the balloon inside tube <NUM> are heat-welded to each other, the distal side sleeve <NUM> and the proximal side sleeve <NUM> to be heat-welded can be integrally welded to the balloon inside tube <NUM>. Therefore, the inner layer <NUM> and the outer layer <NUM> of the balloon inside tube <NUM> are not easily delaminated from each other at a heat-welded portion.

As the thermoplastic polymer that forms the inner layer <NUM>, polyolefin, a polyolefin elastomer, polyester, a polyester elastomer, polyamide, a polyamide elastomer, polyurethane, a polyurethane elastomer, and the like can be used. When adequate flexibility, strength, and processability are taken into consideration, polyamide or a polyamide elastomer is preferably used. In particular, in view of easy forming of the balloon inside tube <NUM>, a polyamide or a polyamide elastomer having a Shore D hardness of 63D or more is more preferably used. Since a polyamide or a polyamide elastomer having a Shore D hardness of 63D to 74D is generally used as the balloon <NUM> of a balloon catheter for PTCA, a polyamide or a polyamide elastomer having a Shore D hardness of 63D to 74D is further more preferably used as the inner layer <NUM> because the interfaces between the inner layer <NUM>, the outer layer <NUM> and the balloon <NUM> can be more firmly welded when the balloon and the balloon inside tube <NUM> are heat-welded to each other.

When the inner layer <NUM> has a multi-layer structure, the highest Shore hardness among the Shore hardnesses of a plurality of thermoplastic polymers is determined as the Shore hardness of the inner layer <NUM>.

"Shore D hardness" described in the present invention indicates a typical value for a particular material and may be different from a Shore D hardness measured by a general measurement method ISO868 (for example, in the case of "PEBAX® <NUM>" manufactured by Arkema Inc. which is a polyamide elastomer, although a measured value of the Shore D hardness thereof is 69D, the Shore D hardness is determined as 70D in the present invention).

The thickness of the inner layer <NUM> may be appropriately determined depending on the intended use of the balloon catheter, and is only required to be in the range of <NUM> to <NUM>.

The outer layer <NUM> of the balloon inside tube <NUM> is only required to be formed of a thermoplastic polymer that can be heat-welded to the balloon <NUM> as well as has a lower melting point than the inner layer <NUM> of the balloon inside tube <NUM>. When the outer layer <NUM> of the balloon inside tube <NUM> is formed of a material that can be heat-welded to the balloon <NUM>, bonding with adhesive, which results in a rigid junction, is not necessary to be performed. Therefore, it is possible for the balloon catheter A to have pliability that is required for a catheter.

As the thermoplastic polymer that forms the outer layer <NUM>, polyolefin, a polyolefin elastomer, polyester, a polyester elastomer, polyamide, a polyamide elastomer, polyurethane, a polyurethane elastomer, and the like can be used. When adequate flexibility, strength, and processability are taken into consideration, polyamide or a polyamide elastomer is preferably used. In order to improve the pliability of the balloon inside tube <NUM>, a polyamide elastomer having a Shore D hardness of 55D or less is more preferably used. Further, in view of more adequate flexibility of the balloon catheter, a polyamide elastomer having a Shore D hardness of 40D to 55D is further more preferably used.

When the outer layer <NUM> has a multi-layer structure, the lowest Shore hardness among the Shore hardnesses of a plurality of thermoplastic polymers is determined as the Shore hardness of the outer layer <NUM>.

In the present invention, the melting point of the thermoplastic polymer that forms the inner layer <NUM> is preferably higher than the melting point of the thermoplastic polymer that forms the outer layer <NUM> by <NUM> to <NUM>, and more preferably by <NUM> to <NUM>. When the difference between the melting point of the thermoplastic polymer forming the inner layer <NUM> and the melting point of the thermoplastic polymer forming the outer layer <NUM> is less than <NUM>, the core member tends to become difficult to pull out. Further, when the difference exceeds <NUM>, there is a tendency for the thermoplastic polymer forming the inner layer <NUM> and the thermoplastic polymer forming the outer layer <NUM> to become difficult to weld to each other, thereby lowering the adhesiveness between the inner layer <NUM> and the outer layer <NUM>.

When the inner layer <NUM> has a multi-layer structure, the above-described melting point is directed to the melting point of a thermoplastic polymer forming a layer that has contact with the outer layer <NUM>. Similarly, when the outer layer <NUM> has a multi-layer structure, the above-described melting point is directed to the melting point of a thermoplastic polymer forming a layer that has contact with the inner layer <NUM>.

The thickness of the outer layer <NUM> may be appropriately determined depending on the intended use of the balloon catheter. In the case of a perfusion balloon catheter, the thickness of the outer layer <NUM> is only required to be in the range of <NUM> to <NUM>.

The form of the support body <NUM> of the balloon inside tube <NUM> is not limited as long as the support body <NUM> achieves improvement of the strength or the like of the balloon inside tube <NUM>. Metal such as superelastic alloy and stainless steel, and a high rigidity resin material such as polyimide, polyamide-imide, and polyetheretherketone can be used as the support body <NUM>. When the support body <NUM> is disposed so as to be embedded in the outer layer <NUM> and extend the entire length of the balloon inside tube <NUM>, it is possible to improve the pressing performance of the balloon catheter. In the present invention, since an outer tube <NUM> for forming the outer layer <NUM> shrinks while being melted by heat-welding, the support body <NUM> exists in an embedded state in the outer layer <NUM>.

In the present invention, in order to improve the buckling strength in the radial direction, the support body <NUM> may be disposed so as to extend over the entire circumference of the balloon inside tube <NUM>. In this case, the support body <NUM> preferably has a coil structure or a braid structure. For example, when the support body <NUM> is formed into a coil shape as shown in <FIG> and <FIG>, it is possible to improve the buckling strength in the radial direction of the balloon-provided part and also impart pliability to the balloon inside tube <NUM>. In this case, a wire-like support body <NUM> may be wound around an inner tube <NUM> for forming the inner layer <NUM> when forming the balloon inside tube <NUM>, or the wire may first be formed into a coil shape and then disposed on the inner tube <NUM>. Further, when the support body <NUM> is formed to have a braid structure, it is possible to improve the buckling strength in the radial direction of the balloon-provided part and the pressing performance for transmitting force applied to the proximal side of the catheter toward the distal side thereof.

The shape of the wire that forms the support body <NUM> is not particularly limited, and the cross section of the wire can be formed into a rectangular shape or a round shape. In the case of a rectangular wire, improvement of the pressing performance in the axial direction can be expected. In the case of a round wire, improvement of the pliability can be expected. The cross-sectional area of the wire can be freely designed in view of the buckling strength, the pressing performance, the pliability and the like.

As shown in <FIG>, in the support body <NUM> having a coil shape, the length of a pitch <NUM> between windings of the coil may be any value as long as it is larger than zero. The shorter the length of the pitch <NUM> is, the more the buckling strength is improved. When the length of the pitch <NUM> is zero, since the outer tube <NUM> for forming the outer layer <NUM> does not reach the surface of the inner tube <NUM> when forming the balloon inside tube <NUM> by heat-welding, the balloon cannot be formed.

In addition, in order to confirm the position of the balloon <NUM> inside the body, the radiopaque marker(s) <NUM> may be disposed on the balloon inside tube <NUM>. The support body <NUM> of the balloon inside tube <NUM> may have radiopaque property, or the radiopaque marker(s) <NUM> may be provided other than the support body <NUM>. Especially when the outer surface of the radiopaque marker(s) <NUM> is not exposed on the outer surface of the balloon inside tube <NUM>, the radiopaque marker(s) <NUM> does not hurt the balloon <NUM>. As a result, the probability of occurrence of a failure such as balloon rupture can be reduced. When the radiopaque marker(s) <NUM> is located at a more inner position in the radial direction than the support body <NUM> of the balloon inside tube <NUM>, it is possible to reduce deviation of the support body <NUM> in the axial direction when forming the balloon inside tube <NUM>.

In view of high efficiency, the balloon inside tube <NUM> having the above structure is produced in accordance with the steps of.

Specifically, as shown in <FIG>, the lumen forming core member <NUM> is first inserted into the inner tube <NUM> for forming the inner layer <NUM> of the balloon inside tube <NUM>.

The inner tube <NUM> may have either a single-layer structure or a multi-layer structure as long as at least it can form the inner layer <NUM>. When the inner tube <NUM> has a multi-layer structure, the inner layer <NUM> may be formed by the most inner layer, and the other layers may be formed of any thermoplastic polymer as long as it can be heat-welded to the balloon <NUM>. In order to improve "pressing performance" for transmitting force applied to the proximal side of the catheter to the distal side thereof, a rigid material can be used. However, in order for the catheter to pass through a curved blood vessel, a pliable material can also be used.

Further, in order to more easily remove the lumen forming core member <NUM> by forming the surface of the inner lumen of the balloon inside tube <NUM> into a rough surface when forming the balloon inside tube <NUM>, the inner layer <NUM> may contain fine particles such as pigment. The fine particles used in this case may be any particles as long as the diameter thereof is <NUM> or less. Examples of the fine particles include, in addition to pigment, inorganic filler such as titanium oxide, calcium carbonate, alumina, and silica, and resin filler such as acrylic resin, silicone resin, and carbon.

The fine particles may be mixed with the thermoplastic polymer which is the material of the inner tube <NUM> when producing the inner tube <NUM>.

The size and the length of the lumen forming core member <NUM> may be appropriately determined depending on the purpose and intended use of the balloon catheter.

If necessary, the radiopaque marker(s) <NUM> is attached to the outside of the inner tube <NUM> as shown in <FIG>.

In this case, the radiopaque marker(s) <NUM> is preferably swaged onto the outer surface of the inner tube <NUM>. Swaging the radiopaque marker(s) <NUM> indicates, for example, a state where the radiopaque marker(s) <NUM> is embedded in the inner layer <NUM> from the surface toward the inside thereof as shown in <FIG>. Swaging means is not particularly limited.

Then, the support body <NUM> is disposed on the outer surface of the inner tube <NUM> (when the radiopaque marker(s) <NUM> is provided, the outer surface(s) of the radiopaque marker(s) <NUM>) as shown in <FIG>. A method for disposing the support body <NUM> is not particularly limited. For example, when the support body <NUM> is formed of a rectangular wire and has a coil shape, the support body <NUM> may be previously formed into a coil shape, and the inner tube <NUM> or the like may be inserted into the support body <NUM> having a coil shape. Alternatively, the support body <NUM> may be wound around the outer surface of the inner tube <NUM> into a coil shape by a conventional method. Further, the catheter inside tube to be obtained tends to become harder when the support body <NUM> is disposed closer to the surface of the inner tube <NUM>. Therefore, by adjusting the position of the support body <NUM>, desired flexibility of the catheter inside tube can be adjusted. The disposing position of the support body <NUM> is not particularly limited. The support body <NUM> may be disposed only within the inner lumen of the balloon <NUM> when the balloon <NUM> is connected to the balloon inside tube <NUM>, may extend to the sleeves of the balloon <NUM>, or may extend beyond the sleeves.

Then, the outer tube <NUM> for forming the outer layer <NUM> of the balloon inside tube <NUM> is disposed on the outside of the support body <NUM> as shown in <FIG>.

The outer tube <NUM> may have either a single-layer structure or multi-layer structure as long as it is formed of a thermoplastic polymer that can be heat-welded to the balloon <NUM> as well as has a lower melting point than the inner layer <NUM> of the balloon inside tube <NUM>. In order to improve "pressing performance", a rigid material can be used. However, in order for the catheter to pass through a curved blood vessel, a pliable material can also be used.

Further, the outer tube <NUM> may be disposed so as to approximately entirely cover the inner tube <NUM>.

Then, the heat-shrinkable tube <NUM> is disposed so as to cover the outside of the outer tube <NUM> as shown in <FIG>. The heat-shrinkable tube <NUM> has a property of shrinking by heat. The material of the heat-shrinkable tube <NUM> is not particularly limited as long as it is used in the art.

Then, the heat-shrinkable tube <NUM> is heated at a temperature that is equal to or higher than the melting point of the thermoplastic polymer that forms the outer layer <NUM> as well as lower than the melting point of the thermoplastic polymer that forms the inner layer <NUM>. In this manner, the outer tube <NUM> which is disposed in the inner lumen of the heat-shrinkable tube <NUM> is melted and thereby heat-welded to the surfaces of the support body <NUM> and the inner tube <NUM>.

In this regard, "melting point" referred to in the present invention indicates a melting point measured by an ASTM D3418 method.

As described above, by performing the heat-welding at a temperature that is equal to or higher than the melting point of the thermoplastic polymer that forms the outer layer <NUM> as well as lower than the melting point of the inner layer <NUM>, the outer tube <NUM> is melted and thereby adheres to the outer surface of the inner tube <NUM> (and the surface(s) of the radiopaque marker(s) <NUM>) while the support body <NUM> is being embedded into the melted outer tube <NUM> as shown in <FIG>. The outer layer <NUM> formed in this manner is integrated with the inner layer <NUM> and the support body <NUM>, thereby making it possible to form the balloon inside tube <NUM> having no defect such as a gap inside thereof.

Further, in the present invention, by performing the heat-welding under the temperature condition described above, the inner tube <NUM> is not melted and is not therefore stuck to the lumen forming core member <NUM>. Therefore, it is easy to remove the lumen forming core member <NUM> after forming the balloon inside tube <NUM>.

A method of the heat-welding is not particularly limited, and a hot air welding machine and an oven can be used. The heat-welding method may be any method as long as it can bring the temperature of an object into a temperature approximately equal to the above-described one by exposing the object under the atmosphere at a temperature of <NUM> to <NUM>, for example.

Then, the heat-shrinkable tube <NUM> can be removed from the inner tube <NUM> to produce the balloon inside tube <NUM>. The heat-shrinkable tube <NUM> is preferably removed after the outer tube <NUM> is cooled to transition from the melted state.

When the balloon inside tube <NUM> has a biaxial structure, the balloon inside tube <NUM> may be produced in such a manner that the inner tube <NUM> having a biaxial structure is previously produced, two lumen forming core members <NUM> are inserted into respective two lumens of the inner tube <NUM>, and the radiopaque marker(s) <NUM>, the support body <NUM>, and the outer tube <NUM> are disposed on the outside of the inner tube <NUM>. Alternatively, the balloon inside tube <NUM> may be produced in such a manner that two inner tubes <NUM> each of which has the lumen forming core member <NUM> inserted thereinto are disposed in parallel to each other, and the radiopaque marker(s) <NUM>, the support body <NUM>, and the outer tube <NUM> are disposed on the outside of the inner tubes <NUM>.

In order to reduce frictional resistance between the balloon inside tube <NUM> and the guide wire <NUM> which passes through the inside of the balloon inside tube <NUM> when performing PTCA, lubricant coating may be applied to the inner surface of the inner layer <NUM> of the balloon inside tube <NUM> after forming the balloon inside tube <NUM>. Examples of the lubricant coating agent include a silicone coating agent such as silicone and polydimethylsiloxane, and an acrylic coating agent such as butyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, octyl (meth) acrylate, and <NUM>, <NUM>, <NUM>-trifluoroethyl methacrylate. The lubricant coating agent may be applied to the inner surface of the inner layer <NUM> by a known method.

The balloon <NUM> is heat-welded to the outer surface of the balloon inside tube <NUM> formed as described above. The balloon <NUM> is only required to be formed of a thermoplastic polymer that can be heat-welded to the outer layer <NUM> of the balloon inside tube <NUM>, and any other limitations are not particularly placed on the material of the balloon <NUM>. Polyolefin, a polyolefin elastomer, polyester, a polyester elastomer, polyamide, a polyamide elastomer, polyurethane, a polyurethane elastomer and the like can be used as the material of the balloon <NUM>. When adequate flexibility, strength, and processability are taken into consideration, polyamide or a polyamide elastomer is preferably used.

The entire length of the balloon <NUM> including the distal side sleeve <NUM> and the proximal side sleeve <NUM> may be appropriately determined depending on the intended use of the balloon catheter. In the case of a perfusion balloon catheter, the length is only required to be in the range of <NUM> to <NUM>. In the case of a perfusion balloon catheter, the diameter of a straight tube portion of the balloon <NUM> is also only required to be in the range of <NUM> to <NUM>. Although the thickness of the balloon <NUM> is also not particularly limited, the thicknesses of both of the straight tube portion and the sleeves are preferably in the range of <NUM> to <NUM>. Further, as shown in <FIG>, the end of the distal side sleeve <NUM> of the balloon <NUM> may be located at a more proximal position than the distal end of the balloon inside tube <NUM>.

In the present invention, the distal side sleeve <NUM> which is positioned at the distal side of the distal part of the balloon <NUM> and the distal part of the balloon inside tube <NUM> are heat-welded. By performing the heat-welding at a temperature equal to or higher than the melting point of the thermoplastic polymer that forms the inner layer <NUM>, the distal side sleeve <NUM>, and the outer layer <NUM> and the inner layer <NUM> of the balloon inside tube <NUM> are integrated with each other, thereby making it possible to further suppress the delamination of the inner layer <NUM> of the balloon inside tube <NUM>.

In addition, the proximal side sleeve <NUM> which is positioned at the proximal side of the proximal part of the balloon <NUM> and the proximal part of the balloon inside tube <NUM> are also heat-welded in the same manner as in the distal part thereof. As a result, the balloon <NUM>, and the outer layer <NUM> and the inner layer <NUM> of the balloon inside tube <NUM> are integrated with each other in the welded portions, and the delamination of the inner layer <NUM> is thereby further suppressed.

For example, a core member is previously inserted between a part of the proximal side sleeve <NUM> and the balloon inside tube <NUM>, and the other part of the proximal side sleeve <NUM>, the other part not having contact with the core member, is heat-welded to the surface of the balloon inside tube <NUM>. Thereafter, the core member is pulled out to thereby form a lumen. As a result, it is possible to allow the inner lumen of the balloon <NUM> and the inflation lumen <NUM> of the distal side shaft <NUM> to communicate with each other through the formed lumen.

Further, as shown in <FIG> and <FIG>, a part of the proximal side sleeve <NUM> of the balloon <NUM> may also be brought to butt against the end of the distal side shaft <NUM> without having contact with the balloon inside tube <NUM>. In this case, the end of the balloon inside tube <NUM> butts against the end of the inside tube of the distal side shaft <NUM>. The upper part of the inner lumen of the balloon <NUM> communicates with the inflation lumen <NUM> of the distal side shaft <NUM>. The lower part of the inner lumen of the balloon <NUM> is closed by the end of the distal side shaft <NUM>. The other circumference of the proximal side sleeve <NUM> may be heat-welded on the surface of the balloon inside tube <NUM>.

Although not shown in the drawings, the end of the distal side shaft <NUM> may be inserted between the proximal side sleeve <NUM> and the balloon inside tube <NUM>, and the surface of the distal side shaft <NUM> and the proximal side sleeve <NUM> may be heat-welded to each other in the same manner as in a common balloon catheter.

The distal end part including the balloon <NUM> which is the characterizing portion of the present invention is formed in the above-described manner.

In the present invention, the configurations other than the configuration of the distal end part, that is, the specific configurations of the distal side shaft <NUM>, the proximal side shaft <NUM>, and the hub <NUM> as shown in <FIG> may be the same as those in a common balloon catheter. The distal side shaft <NUM> may be formed by connecting a plurality of shafts having different cross-sectional shapes in the radial direction. A method for connecting the distal side shaft <NUM>, the proximal side shaft <NUM>, and the hub <NUM> to each other may also be the same as that in a common balloon catheter.

Hereinbelow, specific examples according to the present invention will be described in detail. However, the present invention is not limited to the following examples.

A balloon catheter that includes a balloon inside tube <NUM> including an inner layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 63D, melting point: <NUM>), an outer layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 40D, melting point: <NUM>), and a support body <NUM> which is formed of a metal wire (SUS304), and a balloon <NUM> which is formed of a polyamide elastomer (Shore D hardness: 70D, melting point: <NUM>) was produced according to the following procedure.

As shown in <FIG>, a lumen forming core member <NUM> (SUS304, diameter: <NUM>) the surface of which is coated with parylene was inserted into an inner tube <NUM> (length: <NUM>, inner diameter: <NUM>, thickness: <NUM>) for forming the balloon inside tube <NUM>, the inner tube <NUM> being formed of a polyamide elastomer (Shore D hardness: 63D, melting point: <NUM>). Further, as shown in <FIG>, radiopaque markers <NUM> (made of a platinum-iridium alloy) each of which is formed into a band of <NUM> width were swaged onto the outer surface of the inner tube <NUM>.

Then, as shown in <FIG>, a coil-shaped support body <NUM> (diameter: <NUM>, pitch width: <NUM>) which is formed of a rectangular wire was disposed on the outer surface of the inner tube <NUM> and the outer surfaces of the radiopaque markers <NUM>. The length of the coil-shaped support body <NUM> in the axial direction was made to be the same as the length from the distal end of a distal side sleeve to the proximal end of a proximal side sleeve of the balloon to be heat-welded to the balloon inside tube later.

Then, as shown in <FIG>, an outer tube <NUM> (length: <NUM>) which is formed of two kinds of polyamide elastomers (Shore D hardness: 40D, thickness: <NUM>, melting point: <NUM> in an outer layer; Shore D hardness: 55D, thickness: <NUM>, melting point: <NUM> in an inner layer) was disposed so as to cover the outside of the coil-shaped support body <NUM>.

Then, as shown in <FIG>, a heat-shrinkable tube <NUM> (made of polyolefin, shrinkage temperature: <NUM> or higher, shrinkage rate: <NUM>% or higher, inner diameter before shrinking: approximately <NUM>) was disposed on the outside of the outer tube <NUM>, put in an oven maintained at a constant temperature of <NUM>, and taken out from the oven <NUM> minutes later. Then, the heat-shrinkable tube <NUM> and the lumen forming core member <NUM> were removed therefrom to form the balloon inside tube <NUM> having the structure as shown in <FIG> (length after being cut: <NUM>, inner diameter: <NUM>, outer diameter: <NUM>).

Apart from the above, a tube-shaped parison was produced by extrusion molding using a polyamide elastomer (Shore D hardness: 70D). Then, blow molding was performed using the parison to produce the balloon <NUM> which includes a straight tube portion having an outer diameter of <NUM>, a length of <NUM>, and a thickness of <NUM>. The distal side sleeve <NUM> which was provided in the straight tube portion has an outer diameter of <NUM>. <NUM>, an inner diameter of <NUM>, and a length of <NUM>. The proximal side sleeve <NUM> which was provided in the straight tube portion has an outer diameter of <NUM>. <NUM>, an inner diameter of <NUM>, and a length of <NUM>. The entire length of the balloon <NUM> was <NUM>.

As shown in <FIG>, the balloon <NUM> was disposed on the balloon inside tube <NUM> so that the distal side part of the balloon inside tube <NUM> overlaps with the distal side sleeve <NUM> and the proximal side part of the balloon inside tube <NUM> overlaps with the proximal side sleeve <NUM>. In addition, the balloon <NUM> was disposed so that the end part of the balloon inside tube <NUM> protrudes by <NUM> from the end of the distal side sleeve <NUM>, and the thus protruding part of the balloon inside tube <NUM> was cut to form the distal end of the balloon inside tube <NUM>.

Then, the distal side part of the balloon inside tube <NUM> and the distal side sleeve <NUM> were heat-welded to each other at a temperature that is equal to or higher than the melting point of the material of the inner layer <NUM> of the balloon inside tube <NUM> (<NUM> to <NUM>).

Then, the distal end of a two-hole tube (length: <NUM>, outer diameter: <NUM>, maximum diameter of guide wire lumen <NUM>: <NUM>, maximum diameter of inflation lumen: <NUM>) that has the same cross-sectional configuration as that shown in <FIG> and is made of a polyamide elastomer was brought to butt against the proximal end of the balloon inside tube <NUM>, and the proximal side part of the balloon inside tube <NUM>, the distal part of the two-hole tube, and the proximal side sleeve <NUM> were heat-welded to each other. Specifically, as shown in <FIG>, the end of the proximal side sleeve <NUM> of the balloon <NUM> and the end of the two-hole tube (the distal side shaft <NUM>) were heat-welded to each other (at <NUM> to <NUM>) so that the inflation lumen <NUM> of the two-hole tube to be the distal side shaft <NUM> communicates with the inside of the balloon <NUM>. In addition, the end of the balloon inside tube <NUM> and the end of the two-hole tube were heat-welded to each other (at <NUM> to <NUM>) so that the guide wire lumen <NUM> of the two-hole tube communicates with the balloon inside tube <NUM>.

Then, the proximal part of the two-hole tube was connected to a shaft that has a double-tube structure including an outer tube and an inner tube. Specifically, the distal part of a distal end side outer tube (length: <NUM>, inner diameter: <NUM>, outer diameter: <NUM>) which is formed of a polyamide elastomer and the distal part of a distal end side inner tube (length: <NUM>, inner diameter: <NUM>, outer diameter: <NUM>) which is formed of a polyamide elastomer and polyethylene were heat-welded to the proximal part of the two-hole tube to thereby connect the two kinds of distal side shafts to each other.

Then, as a proximal side shaft to be connected to the distal side shaft, a shaft that includes a metal tube (length: <NUM>, inner diameter: <NUM>, outer diameter: <NUM>) which is formed of SUS304 coated with polytetrafluoroethylene and an intermediate tube (length: <NUM>, inner diameter: <NUM>, outer diameter: <NUM>) which is connected to the distal side of the metal tube and made of a polyamide elastomer was used. In order to improve continuity of rigidity, a metal wire which is made of SUS304 is disposed from the intermediate tube through the distal side shaft, and the distal side shaft <NUM> and the proximal side shaft <NUM> were connected to each other so that a proximal side guide wire port is formed on the junction between the distal side shaft <NUM> and the proximal side shaft <NUM> as shown in <FIG>. The metal wire (length: <NUM>, maximum outer diameter: <NUM>) was disposed in such a manner that the distal end of the metal wire is positioned <NUM> away from the proximal side guide wire port at the distal side thereof.

A hub <NUM> is attached to the proximal end of the proximal side shaft <NUM> so that a device for inflating the balloon <NUM> can be connected to the hub <NUM>, thereby completing the production of the balloon catheter.

As shown in <FIG>, sixteen proximal side perfusion ports <NUM> were formed on the wall of the two-hole tube (the distal side shaft <NUM>), the wall facing the guide wire lumen <NUM> (which also serves as the perfusion lumen <NUM>), so as to be aligned on a straight line at regular intervals. Further, eight distal side perfusion ports <NUM> in total were formed on the wall of the distal side sleeve <NUM> of the balloon <NUM> in such a manner that four sets of distal side perfusion ports <NUM>, each set having two distal side perfusion ports <NUM> shifted in phase by <NUM>° from each other in the circumferential direction, are positioned at regular intervals as well as shifted in phase by <NUM>° from each other in the axial direction. In this manner, the perfusion balloon catheter was produced.

A balloon catheter that includes a balloon inside tube <NUM> including an inner layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 72D, melting point: <NUM>), an outer layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 55D, melting point: <NUM>) and a support body <NUM> which is formed of a metal wire (SUS304), and a balloon <NUM> which is formed of a polyamide elastomer (Shore D hardness: 72D, melting point: <NUM>) was produced according to the following procedure.

The balloon catheter was produced in the same manner as in Example <NUM> excepting that polyamide elastomers (Shore D hardness: 55D in an outer layer, Shore D hardness: 72D in an inner layer) were used as the materials of an inner tube <NUM>, a polyamide elastomer (Shore D hardness: 55D) was used as the material of an outer tube <NUM>, a coil-shaped rectangular wire was used as the support body <NUM>, and a polyamide elastomer (Shore D hardness: 72D) was used as the material of the balloon <NUM>. The thickness of the outer layer of the inner tube <NUM> is <NUM>, the thickness of the inner layer of the inner tube <NUM> is <NUM>, and the thickness of the outer tube <NUM> is <NUM>.

A balloon catheter that includes a balloon inside tube <NUM> including an inner layer <NUM> which is formed of a polyamide (Shore D hardness: 74D, melting point: <NUM> to <NUM>), an outer layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 55D, melting point: <NUM>) and a support body <NUM> which is formed of a metal wire (SUS304), and a balloon <NUM> which is formed of a polyamide elastomer (Shore D hardness: 63D, melting point: <NUM>) was produced according to the following procedure.

The balloon catheter was produced in the same manner as in Example <NUM> excepting that a polyamide (Shore D hardness: 74D, melting point: <NUM> to <NUM>) was used as the material of the inner tube <NUM>, a polyamide elastomer (Shore D hardness: 55D, melting point: <NUM>) was used as the material of the outer tube <NUM>, a coil-shaped round wire was used as the support body <NUM>, and a polyamide elastomer (Shore D hardness: 63D, melting point: <NUM> ) was used as the material of the balloon <NUM>.

A balloon catheter that includes a balloon inside tube <NUM> including an inner layer <NUM> which is formed of a polytetrafluoroethylene (Polyflon® PTFE F207, surface-treated, manufactured by Daikin Industries, Ltd. , melting point: <NUM>), an outer layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 70D, melting point: <NUM>), and a support body <NUM> which is formed of a metal wire (SUS304), and a balloon <NUM> which is formed of a polyamide elastomer (Shore D hardness: 70D, melting point: <NUM>) was produced according to the following procedure.

The balloon catheter was produced in the same manner as in Example <NUM> excepting that the above polytetrafluoroethylene was used as the material of the inner tube <NUM>, a polyamide elastomer (Shore D hardness: 70D, melting point: <NUM>) was used as the material of the outer tube <NUM>, a coil-shaped rectangular wire was used as the support body <NUM>, a polyamide elastomer (Shore D hardness: 70D, melting point: <NUM>) was used as the material of the balloon <NUM>, and a heat-welding temperature at the time of forming the balloon inside tube <NUM> was <NUM>.

A balloon catheter that includes a balloon inside tube <NUM> including an inner layer <NUM> which is formed of a tetrafluoroethylene/perfluoroalkylvinyl ether copolymer (Neoflon® PFAAP210, surface-treated, manufactured by Daikin Industries, Ltd. , melting point: <NUM>), an outer layer <NUM> which is formed of a polyamide elastomer (Shore D hardness: 72D, melting point: <NUM>), and a support body <NUM> which is formed of a metal wire (SUS304), and a balloon <NUM> which is formed of a polyamide elastomer (Shore D hardness: 72D, melting point: <NUM>) was produced according to the following procedure.

The balloon catheter was produced in the same manner as in Example <NUM> excepting that the above tetrafluoroethylene/perfluoroalkylvinyl ether copolymer was used as the material of the inner tube <NUM>, a polyamide elastomer (Shore D hardness: 72D, melting point: <NUM>) was used as the material of the outer tube <NUM>, a coil-shaped rectangular wire was used as the support body <NUM>, a polyamide elastomer (Shore D hardness: 72D, melting point: <NUM>) was used as the material of the balloon <NUM>, and a heat-welding temperature at the time of forming the balloon inside tube <NUM> was <NUM>.

A balloon inside tube <NUM> that includes an inner layer <NUM> and an outer layer <NUM> each of which is formed of a polyamide (Shore D hardness: 55D, melting point: <NUM>), and a support body <NUM> which is formed of a metal wire (SUS304) was produced according to the following procedure.

A lumen forming core member <NUM> (SUS304) the surface of which is coated with parylene was inserted into an inner tube <NUM> for forming the balloon inside tube <NUM>, the inner tube <NUM> being formed of a polyamide elastomer (Shore D hardness: 55D, melting point <NUM>). Radiopaque markers <NUM> (platinum-iridium alloy) were swaged onto the outer surface of the inner tube <NUM>. Further, the coil-shaped support body <NUM> which is formed of a round wire was disposed on the outer surface of the inner tube <NUM> and the outer surfaces of the radiopaque markers <NUM>. The length of the coil-shaped support body <NUM> in the axial direction was made to be the same as the length from the distal end of a distal side sleeve <NUM> to the proximal end of a proximal side sleeve <NUM>. An outer tube <NUM> which is formed of a polyamide elastomer (Shore D hardness: 55D, melting point <NUM>) was disposed so as to cover the outside of the coil-shaped support body <NUM>. Further, a heat-shrinkable tube <NUM> (made of polyolefin, shrinkage temperature: <NUM> or higher, shrinkage rate: <NUM>% or higher, inner diameter before shrinking: approximately <NUM>) was disposed on the outside of the outer tube <NUM>, put in an oven maintained at a constant temperature of <NUM>, and taken out from the oven <NUM> minutes later. Then, the heat-shrinkable tube <NUM> was removed therefrom. However, the lumen forming core member <NUM> could not be pulled out therefrom.

Claim 1:
A balloon catheter (A; A') comprising:
a balloon (<NUM>); and
a balloon inside tube (<NUM>) passing through an inner lumen of the balloon (<NUM>), the balloon inside tube (<NUM>) including an inner layer (<NUM>), an outer layer (<NUM>), and a support body (<NUM>),
wherein the balloon (<NUM>), the inner layer (<NUM>), and the outer layer (<NUM>) are formed of thermoplastic polymers that can be heat-welded to each other, and
a thermoplastic polymer forming the inner layer (<NUM>) has a higher melting point than a thermoplastic polymer forming the outer layer (<NUM>);
characterized in that
the balloon (<NUM>) has a distal side sleeve (<NUM>) at a distal side thereof, and the distal side sleeve (<NUM>) is heat-welded to a distal part of the balloon inside tube (<NUM>) at a temperature equal to or higher than the melting point of the thermoplastic polymer forming the inner layer (<NUM>) of the balloon inside tube (<NUM>).