Patent Description:
In recent years, a catheter that can be inserted into a body cavity such as a blood vessel has been developed (for example, Patent Document <NUM>).

In general, the catheter is inserted into the body cavity by an over-the-wire method using a guide wire. According to this method, a distal portion of the guide wire inserted into the catheter is projected from a distal end of the catheter. After a distal end of the guide wire reaches a desired bifurcated path, the catheter is pushed along the guide wire so that the catheter is inserted into the desired bifurcated path.

Patent Document <NUM> discloses a catheter with a catheter main body comprising an inner layer, an outer layer formed on the outer peripheral side of the inner layer and a coil installed between the inner layer and the outer layer. The coil is composed by helically winding one continuous wire body and is constituted of a radiopaque metal material.

Patent Document <NUM> discloses a catheter with a catheter body including a hollow coil whose outer and inner peripheral surfaces are coated with an outer resin layer and an inner resin layer.

Patent Document <NUM> discloses a catheter comprising a resinous inner/outer layer tube mutually laminated, and a reinforcing layer provided between the inner and outer layer tube for reinforcing them.

Patent Document <NUM> discloses a catheter with a main body having a main section and a front end section. The main section is constituted in such a way that an intermediate layer is formed on the outer periphery of an inner layer and an outer layer is formed on the outer periphery of the layer.

Patent Document <NUM> discloses a catheter tube with an inner layer formed in a tubular shape having flexibility, which extends from the main body part to the front end. The internal space thereof constitutes a lumen and the inside surface of the inner layer is provided with a hydrophilic lubricating layer.

Human blood vessels include a blood vessel called a relatively narrow perforator bifurcated from a relatively wide blood vessel. In a case where a desired bifurcated path is a narrow blood vessel such as the perforator, an AVM, a vertebral artery, or a vasa vasorum connected to a tumor, even a skilled operator cannot always easily insert a commercially available catheter into the blood vessel to reach a sufficient depth position of the bifurcated path.

The present invention is made in view of the above-described problem, and aims to provide a catheter and a catheter kit which have a structure enabling a medical procedure to be preferably performed so that the catheter is guided by a guide wire to enter the narrow blood vessel such as the perforator, the AVM, the vertebral artery, or the vasa vasorum connected to the tumor.

The present applicatior provides a catheter including a catheter body having a resin layer including an inner layer having a lumen and an outer layer formed in an outer periphery of the inner layer, and a reinforcement layer incorporated in the resin layer and disposed around the lumen and around the inner layer so as to surround the inner layer, a ring-shaped marker made of a radiopaque metal material, the marker being incorporated in the resin layer in a distal end of the catheter body, fixed to a distal end of the reinforcement layer, and disposed around the lumen, and a distal tip made of a resin linked to the distal end of the catheter body, the distal tip having a distal lumen which communicates with the lumen and has an open distal end. An outer diameter of the distal end of the catheter body is <NUM> or smaller, a maximum outer diameter of the distal tip is <NUM> or smaller. The reinforcement layer is configured to include a first braid and a second braid disposed in an outer periphery of the first braid. The first braid is continuously disposed from the distal end to a proximal end of the catheter body. The second braid is continuously disposed from an intermediate portion to the proximal end of the catheter body but is not disposed in a distal portion of the catheter body. The distal tip has a Shore D hardness, as measured according to ISO686, of <NUM> to <NUM>. A dimension of the marker in an axial direction of the catheter body is smaller than the maximum outer diameter of the distal tip. The length of the distal tip in the axial direction of the distal tip is <NUM> times to <NUM> times the maximum outer diameter of the distal tip.

With the catheter of the present invention, a medical procedure can be performed so that the catheter is guided by the guide wire to enter the narrow blood vessel such as the perforator, the AVM, the vertebral artery, or the vasa vasorum connected to the tumor.

In all of the drawings, the same reference numerals will be given to the same configuration elements, and description thereof will be omitted as appropriate.

Terms used in describing the embodiments of the present invention are defined as follows, unless otherwise specified.

In describing the embodiments, the terms of a distal portion and a proximal portion may be used as appropriate, in some cases. The distal portion refers to a predetermined length region including an end (distal end) on an insertion distal side of a catheter in each portion of the catheter. In addition, the proximal portion refers to a predetermined length region including an end (proximal end) on a proximal side of the catheter in each portion of the catheter.

In addition, an axis means a central axis extending along a longitudinal direction of a catheter body.

A longitudinal cross section of the catheter refers to a cross section obtained by cutting the catheter along the axis.

First, a first embodiment will be described with reference to <FIG>.

As shown in any of <FIG>, a catheter <NUM> according to the present embodiment includes an elongated catheter body <NUM> having a resin layer <NUM> including an inner layer <NUM> having a lumen <NUM> and an outer layer <NUM> formed in an outer periphery of the inner layer <NUM>, and a reinforcement layer <NUM> incorporated in the resin layer <NUM> and disposed around the lumen <NUM> and around the inner layer (<NUM>) so as to surround the inner layer (<NUM>).

Furthermore, the catheter <NUM> includes a ring-shaped marker <NUM> made of a radiopaque metal material (for example, a platinum alloy). The marker <NUM> is incorporated in the resin layer <NUM> in a distal end of the catheter body <NUM>, is fixed to a distal end of the reinforcement layer <NUM>, and is disposed around the lumen <NUM>.

Furthermore, the catheter <NUM> includes a resin-made distal tip <NUM> linked to the distal end of the catheter body <NUM>. The distal tip <NUM> has a distal lumen <NUM> having an open distal end, and the distal lumen <NUM> communicates with the lumen <NUM>. Hereinafter, an opening in the distal end of the distal lumen <NUM> will be referred to as a distal opening <NUM>.

The catheter <NUM> is an inactive type microcatheter in which an outer diameter of the distal end of the catheter body <NUM> is <NUM> or smaller and a maximum outer diameter of the distal tip <NUM> is <NUM> or smaller. Here, the inactive type means a device that changes a curvature of at least a portion of the catheter in a blood vessel and does not depend on electric energy or other power sources (power sources other than power generated by a human body or gravity).

A dimension (length) of the marker <NUM> in the axial direction of the catheter body <NUM> is smaller than a maximum outer diameter of the distal tip <NUM>.

Then, a length of the distal tip <NUM> in the axial direction of the distal tip <NUM> is <NUM> times to <NUM> times the maximum outer diameter of the distal tip <NUM>.

In a case of the present embodiment, as will be described later, the reinforcement layer disposed on a distal side of the catheter body <NUM> is a braid (first braid <NUM>).

In this case, the length of the distal tip <NUM> in the axial direction of the distal tip <NUM> is preferably <NUM> times to <NUM> times the maximum outer diameter of the distal tip <NUM>, more preferably <NUM> times to <NUM> times, and much more preferably <NUM> times to <NUM> times.

In each of <FIG>, dimensions of the catheter body <NUM> and the distal tip <NUM> in a radial direction are significantly enlarged in the illustration.

According to the catheter <NUM> having this configuration, a medical procedure can be preferably performed so that the catheter <NUM> enters a narrow blood vessel such as a perforator, an AVM, a vertebral artery, or a vasa vasorum connected to a tumor. For example, as shown in time-series operation examples in <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> or <FIG>, <FIG>, and <FIG>, a medical procedure can be preferably performed so that the catheter <NUM> enters a small diameter blood vessel (for example, a perforator <NUM>) bifurcated from a relatively large diameter artery (internal carotid artery <NUM>) through the artery.

That is, the distal tip <NUM> is configured to be sufficiently soft (as will be described later, Shore D hardness of the distal tip <NUM> is <NUM> or lower, for example). In this manner, while the distal tip <NUM> can satisfactorily follow a bent shape of a guide wire <NUM>, the distal tip <NUM> can enter the perforator <NUM> along the guide wire <NUM>.

In particular, a medical procedure can be preferably performed so that the catheter <NUM> enters the perforator <NUM> through the internal carotid artery <NUM> having an inner diameter of approximately <NUM>.

Hereinafter, the present embodiment will be described in more detail.

In a case of the present embodiment, the resin layer <NUM> forming the catheter body <NUM> has a layer structure including an inner layer <NUM> and an outer layer <NUM> which are respectively made of a resin material. The resin layer <NUM> may be configured to include a hydrophilic coat (to be described below).

The inner layer <NUM> has a hollow tube structure. The lumen <NUM> is an internal space of the inner layer <NUM>. The lumen <NUM> is continuously formed from the distal end to the proximal end of the catheter body <NUM>, and the distal end and the proximal end of the catheter body <NUM> are respectively open.

The outer layer <NUM> has a hollow tube structure coaxial with the inner layer <NUM>, and an inner peripheral surface of the outer layer <NUM> is joined to an outer peripheral surface of the inner layer <NUM>.

A resin material forming the inner layer <NUM> and a resin material forming the outer layer <NUM> may be different from each other, or may be equal to each other.

The distal tip <NUM> has the same layer structure as the resin layer <NUM> of the catheter body <NUM>. That is, the distal tip <NUM> has a two layer structure having the inner layer <NUM> and the outer layer <NUM>.

The inner layer <NUM> has a hollow tube structure. The distal lumen <NUM> is an internal space of the inner layer <NUM>. The distal lumen <NUM> is continuously formed from the distal end to the proximal end of the distal tip <NUM>. The proximal end of the distal lumen <NUM> communicates with the distal end of the lumen <NUM>. The distal lumen <NUM> is open in the distal end (distal opening <NUM>).

The inner layer <NUM> is linked to the distal side of the inner layer <NUM>.

The outer layer <NUM> is linked to the distal side of the outer layer <NUM>.

The inner diameter and the outer diameter of the inner layer <NUM> in the distal end of the catheter body <NUM> are equal to the inner diameter and the outer diameter of the inner layer <NUM> in the proximal end of the distal tip <NUM>.

The inner diameter and the outer diameter of the outer layer <NUM> in the distal end of the catheter body <NUM> are equal to the inner diameter and the outer diameter of the outer layer <NUM> in the proximal end of the distal tip <NUM>.

In a case of the present embodiment, the outer diameter of the distal tip <NUM> is constant regardless of a position of the distal tip <NUM> in an axial direction.

Here, a fact that the inner diameter and the outer diameter of the distal tip <NUM> are constant regardless of the position of the distal tip <NUM> in the axial direction means that a change in the outer diameter and a change in the inner diameter of the distal tip <NUM> which correspond to the position of the distal tip <NUM> in the axial direction respectively fall within a range of ± <NUM>%, and each of the changes preferably falls within a range of ± <NUM>%.

A corner portion on an outer peripheral side of the distal end of the distal tip <NUM> may have an R-chamfered shape. In this case, except for a distal region where the corner portion has the R-chamfered shape in the axial direction of the distal tip <NUM>, the outer diameter of the distal tip <NUM> is constant regardless of the position of the distal tip <NUM> in the axial direction.

The Shore D hardness of the distal tip <NUM> is <NUM> or lower. The Shore D hardness of the distal tip <NUM> is <NUM> or higher. The Shore D hardness is determined in accordance with ISO868.

Here, the Shore D hardness of the distal tip <NUM> is the Shore D hardness on an outer surface side of the distal tip <NUM>. In a case of the present embodiment, the Shore D hardness is the Shore D hardness of the outer layer <NUM>.

In the case of the present embodiment, the reinforcement layer <NUM> is disposed around the inner layer <NUM> so as to surround the inner layer <NUM>.

The reinforcement layer <NUM> is configured to include a first braid <NUM> and a second braid <NUM> disposed in an outer periphery of the first braid <NUM>.

More specifically, the first braid <NUM> is continuously disposed from the distal end to the proximal end of the catheter body <NUM> (refer to <FIG> and <FIG>).

On the other hand, the second braid <NUM> is continuously disposed from an intermediate portion to the proximal end of the catheter body <NUM>, but is not disposed in the distal portion of the catheter body <NUM> (refer to <FIG>).

The first braid <NUM> is configured so that a plurality of wires are braided. Preferably, the first braid <NUM> is configured so that the plurality of wires by the plurality of wires are wound in mutually opposite directions.

As an example, the first braid <NUM> is configured so that eight wires of a first wire <NUM> to an eighth wire <NUM> are braided. However, the number of wires forming the first braid <NUM> is not limited to this example.

Each of these wires is a single wire (not a stranded wire), for example. A cross-sectional shape of these wires is not particularly limited. However, for example, a circular shape may be adopted. That is, the wire forming the first braid <NUM> is a round wire, for example. The outer diameters of the first wire <NUM> to the eighth wire <NUM> are equal to each other, for example.

Out of the wires forming the first braid <NUM>, four wires of the first wire <NUM>, the second wire <NUM>, the third wire <NUM>, and the fourth wire <NUM> spirally extend parallel to each other. That is, the first wire <NUM> to the fourth wires <NUM> are spirally wound around the inner layer <NUM> at a substantially equal interval in the axial direction of the catheter body <NUM>.

The remaining fifth wire <NUM>, sixth wire <NUM>, seventh wire <NUM>, and eighth wire <NUM> spirally extend parallel to each other. That is, the fifth wire <NUM> to the eighth wire <NUM> are spirally wound around the inner layer <NUM> at a substantially equal interval in the axial direction of the catheter body <NUM>.

However, a turning direction of a spiral formed by the first wire <NUM> to the fourth wire <NUM> and a turning direction of a spiral formed by the fifth wire <NUM> to the eighth wire <NUM> are mutually opposite directions (opposite to each other). Therefore, the first wire <NUM> to the fourth wire <NUM> and the fifth wire <NUM> to the eighth wire <NUM> periodically intersect each other in the axial direction of the catheter body <NUM>.

In a case of the present embodiment, each pitch P (<FIG>) of the wires forming the first braid <NUM> is larger than the outer diameter of the distal portion (for example, a distal side small diameter region <NUM> to be described later) of the catheter body <NUM>. Here, as shown in <FIG>, with regard to the pitch P of the first wire <NUM>, the pitch P is an inter-axis distance of a pair of adjacent winding portions in each wire.

In this way, a portion of the reinforcement layer <NUM> which is disposed in the distal portion (for example, the distal side small diameter region <NUM>) of the catheter body <NUM> is configured to include the braid (first braid <NUM>) in which the wires (for example, the first wire <NUM> to the eighth wire <NUM>) are braided. The pitch of the wires is larger than the outer diameter of the distal portion of the catheter body <NUM>.

According to this structure, wrinkle forming on the outer surface of the inner layer <NUM> can be suppressed. The outer surface of the inner layer <NUM> can be flattened, and the thickness of the inner layer <NUM> can be uniform in the axial direction of the catheter body <NUM>. In addition, according to this structure, both stiffness and flexibility of the distal portion of the catheter body <NUM> can be properly and compatibly achieved.

For example, the first braid <NUM> is configured so that the wires are wound at a constant pitch from the distal end to the proximal end of the first braid <NUM>.

The second braid <NUM> is configured by braiding a plurality of wires.

As an example, the second braid <NUM> is configured so that the eight wires of the first wire <NUM> to the eighth wire <NUM> are braided. However, the number of wires forming the second braid <NUM> is not limited to this example.

Each of these wires is a single wire (not a stranded wire), for example. The cross-sectional shape of these wires is not particularly limited. However, for example, a flat rectangular shape is adopted. That is, the wire forming the second braid <NUM> is a rectangular wire, for example. The cross-sectional shapes and cross-sectional areas of the first wire <NUM> to the eighth wire <NUM> are equal to each other, for example.

Out of the wires forming the second braid <NUM>, the four wires of the first wire <NUM>, the second wire <NUM>, the third wire <NUM>, and the fourth wire <NUM> spirally extend parallel to each other. That is, the first wire <NUM> to the fourth wires <NUM> are spirally wound around the first braid <NUM> at a substantially equal interval in the axial direction of the catheter body <NUM>.

The remaining fifth wire <NUM>, sixth wire <NUM>, seventh wire <NUM>, and eighth wire <NUM> spirally extend parallel to each other. That is, the fifth wire <NUM> to the eighth wire <NUM> are spirally wound around the first braid <NUM> at a substantially equal interval in the axial direction of the catheter body <NUM>.

Here, the cross-sectional area of the first wire <NUM> to the eighth wire <NUM> forming the second braid <NUM> is larger than the cross-sectional area of the first wire <NUM> to the eighth wire <NUM> forming the first braid <NUM>.

That is, a proximal side portion of the reinforcement layer <NUM> from the intermediate portion in the longitudinal direction of the catheter body <NUM> is configured to include the first braid <NUM> and the second braid <NUM> braided in the outer periphery of the first braid <NUM>. The cross-sectional area of each wire forming the second braid <NUM> is larger than the cross-sectional area of each wire forming the first braid <NUM>.

In this manner, the portion from the intermediate portion to the proximal side portion of the catheter body <NUM> can have sufficiently ensured rigidity. Accordingly, pushing ability of the catheter <NUM> can be satisfactorily realized.

The ring-shaped marker <NUM> is disposed around the inner layer <NUM> coaxially with the inner layer <NUM> and the outer layer <NUM>.

As described above, the marker <NUM> is fixed to the distal end of the reinforcement layer <NUM>. More specifically, for example, the marker <NUM> is disposed around the distal end of the first braid <NUM>, and is fixed to the distal end of the first braid <NUM> by means of caulking. However, the marker <NUM> may be linked to the distal side of the first braid <NUM> by being joined to the distal side of the distal end of the first braid <NUM>.

As described above, a dimension of the marker <NUM> in the axial direction of the catheter body <NUM>, that is, an axial length of the marker <NUM> is smaller than the maximum outer diameter of the distal tip <NUM>.

The axial length of the marker <NUM> is preferably <NUM> to <NUM>, and can be typically set to approximately <NUM>.

In addition, the axial length of the marker <NUM> is preferably shorter than the outer diameter of the marker <NUM>, and more preferably shorter than the inner diameter of the marker <NUM>.

As shown in <FIG>, the catheter body <NUM> has a first distal region <NUM> connected to the proximal side of the distal tip <NUM>, and a second distal region <NUM> connected to the proximal side of the first distal region <NUM>.

The first distal region <NUM> is made of the same resin material as the distal tip <NUM>. More specifically, a resin material forming the inner layer <NUM> in the first distal region <NUM> and a resin material forming the inner layer <NUM> of the distal tip <NUM> are the same material. A resin material forming the outer layer <NUM> in the first distal region <NUM> and a resin material forming the outer layer <NUM> of the distal tip <NUM> are the same material.

The second distal region <NUM> is made of the resin material harder than the resin material forming the first distal region <NUM>. More specifically, for example, the inner layer <NUM> is made of the same resin material from the distal end to the proximal end of the catheter body <NUM>. Therefore, the resin material forming the inner layer <NUM> in the second distal region <NUM> and the resin material forming the inner layer <NUM> in the first distal region <NUM> are the same material. However, the resin material forming the outer layer <NUM> in the second distal region <NUM> is harder than the resin material forming the outer layer <NUM> in the first distal region <NUM>. For example, in a case where both the outer layer <NUM> in the second distal region <NUM> and the outer layer <NUM> in the first distal region <NUM> are made of a polyether block amide copolymer, as the polyether block amide copolymer forming the outer layer <NUM> in the second distal region <NUM>, the copolymer having the Shore D hardness higher than the Shore D hardness of the polyether block amide copolymer forming the outer layer <NUM> in the first distal region <NUM> is selected.

Then, the reinforcement layer <NUM> is continuously disposed throughout the first distal region <NUM> and the second distal region <NUM>. More specifically, as shown in <FIG>, the first braid <NUM> is continuously disposed throughout the first distal region <NUM> and the second distal region <NUM>.

According to this configuration, the rigidity of the distal portion of the catheter body <NUM> can be gradually improved toward the proximal side. Accordingly, the pushing ability in the distal portion of the catheter body <NUM> can be properly realized. An excessive and discontinuous change in the rigidity can be suppressed in a boundary between the first distal region <NUM> and the second distal region <NUM>.

For example, the Shore D hardness of the second distal region <NUM> can be <NUM> times to <NUM> times the Shore D hardness of the distal tip <NUM> and the first distal region <NUM>.

The Shore D hardness of the first distal region <NUM> and the second distal region <NUM> is the Shore D hardness of each outer surface side.

The catheter body <NUM> has an enlarged diameter region <NUM> in which the inner diameter of the lumen <NUM> and the outer diameter of the catheter body <NUM> are gradually enlarged toward the proximal side. The enlarged diameter region <NUM> is closer to the proximal side than the second distal region <NUM>.

For example, in the enlarged diameter region <NUM>, the inner diameter of the lumen <NUM> and the outer diameter of the catheter body <NUM> are gradually enlarged in a linearly tapered shape toward the proximal side.

According to this configuration, the rigidity of the catheter body <NUM> can be gradually improved toward the proximal side in the enlarged diameter region <NUM>, and the pushing ability of the catheter body <NUM> can be satisfactorily realized.

In addition, a liquid such as a drug solution can be smoothly supplied to the distal portion of the catheter body <NUM> via the lumen <NUM>.

In a region (fourth distal region <NUM> shown in <FIG>) of the catheter body <NUM> from the distal side of the enlarged diameter region <NUM> to the proximal side of the enlarged diameter region <NUM>, the resin layer <NUM> is made of the same resin material. More specifically, the material of the inner layer <NUM> is the same resin material (for example, PTFE) from the distal end to the proximal end of the fourth distal region <NUM>, and the material of the outer layer <NUM> is the same resin material (for example, a polyether block amide copolymer) from the distal end to the proximal end of the fourth distal region <NUM>.

According to this configuration, a discontinuous change in the rigidity can be suppressed in a boundary between the enlarged diameter region <NUM> and a region (distal side small diameter region <NUM> shown in <FIG>) adjacent to the distal side of the enlarged diameter region <NUM> in the catheter body <NUM>. In addition, a discontinuous change in the rigidity can be suppressed in a boundary between the enlarged diameter region <NUM> and a region (small diameter region <NUM> shown in <FIG>) adjacent to the proximal side of the enlarged diameter region <NUM> in the catheter body <NUM>.

Therefore, each kink occurrence can be suppressed in the distal end and the proximal end of the enlarged diameter region <NUM>.

As shown in <FIG>, a region adjacent to the proximal side of the enlarged diameter region <NUM> in the catheter body <NUM> is a small diameter region <NUM> having the same outer diameter as the proximal end of the enlarged diameter region <NUM>. A region adjacent to the proximal side of the small diameter region <NUM> in the catheter body <NUM> is a large diameter region <NUM> having the larger diameter than the small diameter region <NUM>.

The proximal side of the catheter body <NUM> includes the large diameter region <NUM>. Accordingly, the portion on the proximal side of the catheter body <NUM> can have sufficiently ensured rigidity, and the pushing ability of the catheter <NUM> can be satisfactorily realized.

For example, an outer diameter change region <NUM> whose outer diameter gradually increases toward the proximal side is disposed between the small diameter region <NUM> and the large diameter region <NUM>.

In addition, for example, in the portions (small diameter region <NUM>, outer diameter change region <NUM>, and large diameter region <NUM>) on the proximal side of the enlarged diameter region <NUM> in the catheter body <NUM>, the inner diameter of the lumen <NUM> is constant.

In addition, for example, a region on the distal side of the enlarged diameter region <NUM> in the catheter body <NUM> is a distal side small diameter region <NUM> whose inner diameter and outer diameter are constant regardless of the position of the catheter body <NUM> in the axial direction.

The inner diameter (inner diameter of the lumen <NUM>) and the outer diameter of the distal side small diameter region <NUM> are equal to the inner diameter and the outer diameter of the distal end of the enlarged diameter region <NUM>.

Here, a fact that the inner diameter and the outer diameter of the distal side small diameter region <NUM> are constant regardless of the position of the catheter body <NUM> in the axial direction means that a change in the outer diameter and a change in the inner diameter of the distal side small diameter region <NUM> which correspond to the position of the catheter body <NUM> in the axial direction respectively fall within a range of ± <NUM>%, and each of the changes preferably falls within a range of ± <NUM>%.

For example, the distal side small diameter region <NUM> includes the first distal region <NUM> and the second distal region <NUM> as described above, and additionally includes a third distal region <NUM>.

The third distal region <NUM> is connected to the proximal side of the second distal region <NUM>. The third distal region <NUM> is made of a resin material which is harder than the resin material forming the second distal region <NUM>. More specifically, the resin material forming the inner layer <NUM> in the second distal region <NUM> and the resin material forming the inner layer <NUM> in the third distal region <NUM> are the same material. However, the resin material forming the outer layer <NUM> in the third distal region <NUM> is harder than the resin material forming the outer layer <NUM> in the second distal region <NUM>. For example, in a case where the resin material forming the outer layer <NUM> in the second distal region <NUM> and the outer layer <NUM> in the third distal region <NUM> is a polyether block amide copolymer, as the polyether block amide copolymer forming the outer layer <NUM> in the third distal region <NUM>, the copolymer having the Shore D hardness higher than the Shore D hardness of the polyether block amide copolymer forming the outer layer <NUM> in the second distal region <NUM> is selected.

Then, the first braid <NUM> is continuously disposed throughout the second distal region <NUM> and the third distal region <NUM>.

Furthermore, the distal side small diameter region <NUM> includes the distal portion of the fourth distal region <NUM>.

The proximal end of the fourth distal region <NUM> is located in an intermediate portion between the distal end and the proximal end of the small diameter region <NUM> described above.

The fourth distal region <NUM> is made of a resin material which is harder than the resin material forming the third distal region <NUM>. More specifically, the resin material forming the inner layer <NUM> in the third distal region <NUM> and the resin material forming the inner layer <NUM> in the fourth distal region <NUM> are the same material. However, the resin material forming the outer layer <NUM> in the fourth distal region <NUM> is harder than the resin material forming the outer layer <NUM> in the third distal region <NUM>. For example, in a case where the resin material forming the outer layer <NUM> in the third distal region <NUM> and the outer layer <NUM> in the fourth distal region <NUM> is a polyether block amide copolymer, as the polyether block amide copolymer forming the outer layer <NUM> in the fourth distal region <NUM>, the copolymer having the Shore D hardness higher than the Shore D hardness of the polyether block amide copolymer forming the outer layer <NUM> in the third distal region <NUM> is selected.

The catheter body <NUM> further includes a fifth distal region <NUM> connected to the proximal side of the fourth distal region <NUM>, a sixth distal region <NUM> connected to the proximal side of the fifth distal region <NUM>, and an intermediate/proximal region <NUM> connected to the proximal side of the sixth distal region <NUM>.

The fifth distal region <NUM> is made of a resin material which is harder than the resin material forming the fourth distal region <NUM>. More specifically, the resin material forming the inner layer <NUM> in the fourth distal region <NUM> and the resin material forming the inner layer <NUM> in the fifth distal region <NUM> are the same material. However, the resin material forming the outer layer <NUM> in the fifth distal region <NUM> is harder than the resin material forming the outer layer <NUM> in the fourth distal region <NUM>. For example, in a case where the resin material forming the outer layer <NUM> in the fourth distal region <NUM> and the outer layer <NUM> in the fifth distal region <NUM> is a polyether block amide copolymer, as the polyether block amide copolymer forming the outer layer <NUM> in the fifth distal region <NUM>, the copolymer having the Shore D hardness higher than the Shore D hardness of the polyether block amide copolymer forming the outer layer <NUM> in the fourth distal region <NUM> is selected.

The sixth distal region <NUM> is made of a resin material which is harder than the resin material forming the fifth distal region <NUM>. More specifically, the resin material forming the inner layer <NUM> in the fifth distal region <NUM> and the resin material forming the inner layer <NUM> in the sixth distal region <NUM> are the same material. However, the resin material forming the outer layer <NUM> in the sixth distal region <NUM> is harder than the resin material forming the outer layer <NUM> in the fifth distal region <NUM>. For example, in a case where the resin material forming the outer layer <NUM> in the fifth distal region <NUM> and the outer layer <NUM> in the sixth distal region <NUM> is a polyether block amide copolymer, as the polyether block amide copolymer forming the outer layer <NUM> in the sixth distal region <NUM>, the copolymer having the Shore D hardness higher than the Shore D hardness of the polyether block amide copolymer forming the outer layer <NUM> in the fifth distal region <NUM> is selected.

The intermediate/proximal region <NUM> is made of a resin material which is harder than the resin material forming the sixth distal region <NUM>. More specifically, the resin material forming the inner layer <NUM> in the sixth distal region <NUM> and the resin material forming the inner layer <NUM> in the intermediate/proximal region <NUM> are the same material. However, the resin material forming the outer layer <NUM> in the intermediate/proximal region <NUM> is harder than the resin material forming the outer layer <NUM> in the sixth distal region <NUM>. For example, in a case where the resin material forming the outer layer <NUM> in the sixth distal region <NUM> and the outer layer <NUM> in the intermediate/proximal region <NUM> is a polyether block amide copolymer, as the polyether block amide copolymer forming the outer layer <NUM> in the intermediate/proximal region <NUM>, the copolymer having the Shore D hardness higher than the Shore D hardness of the polyether block amide copolymer forming the outer layer <NUM> in the sixth distal region <NUM> is selected.

The small diameter region <NUM> includes the distal portion of the fifth distal region <NUM>.

The outer diameter change region <NUM> is configured to include another portion of the fifth distal region <NUM>.

The distal portion of the large diameter region <NUM> is configured to include still another portion of the fifth distal region <NUM>, the sixth distal region <NUM>, and the intermediate/proximal region <NUM>.

For example, the distal end of the second braid <NUM> is located in the proximal portion of the sixth distal region <NUM>.

In addition, if necessary, a hydrophilic coat may be formed on the outer surface layer of the distal side portion of the catheter body <NUM> and the outer surface layer of the distal tip <NUM>. For example, the hydrophilic coat is formed on the outer surface layer from the distal portion of the intermediate/proximal region <NUM> to the distal end of the catheter body <NUM>, and on the outer surface layer of the distal tip <NUM>.

Here, a dimension example of each portion of the catheter <NUM> will be described.

The length of the distal tip <NUM> in the axial direction of the distal tip <NUM> is preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, and much more preferably from <NUM> to <NUM>. Typically, the length can be approximately <NUM>. The length of the distal tip <NUM> is preferably set to the length equal to the inner diameter of a relatively large diameter blood vessel (such as an internal carotid artery) before the blood vessel is bifurcated into a small diameter blood vessel such as a perforator.

The length of the first distal region <NUM> in the axial direction of the catheter body <NUM> is preferably <NUM> to <NUM>. Typically, the length can be approximately <NUM>.

The length of the second distal region <NUM> in the axial direction of the catheter body <NUM> is preferably <NUM> to <NUM>. Typically, the length can be approximately <NUM>.

An effective length of the catheter <NUM> including the distal tip <NUM> and a portion that can be inserted into a body cavity in the catheter body <NUM> is preferably <NUM> to <NUM>. Typically, the effective length can be approximately <NUM>.

The maximum outer diameter of the distal tip <NUM> is <NUM> or smaller as described above. The maximum outer diameter of the distal tip <NUM> is more preferably <NUM> or smaller. The maximum outer diameter of the distal tip <NUM> is preferably <NUM> or larger. Typically, the maximum outer diameter can be <NUM> to <NUM>.

The outer diameter of the distal side small diameter region <NUM> is <NUM> or smaller as described above. The outer diameter of the distal side small diameter region <NUM> is more preferably <NUM> or smaller. The outer diameter of the distal side small diameter region <NUM> is preferably <NUM> or larger. Typically, the outer diameter can be <NUM> to <NUM>.

The inner diameter of the distal tip <NUM> (inner diameter of the distal lumen <NUM>) and the inner diameter of the distal side small diameter region <NUM> (inner diameter of the lumen <NUM> in the distal side small diameter region <NUM>) are preferably <NUM> to <NUM>.

The outer diameter of each wire (first wire <NUM> to eighth wire <NUM>) forming the first braid <NUM> is preferably <NUM> to <NUM>. Typically, the outer diameter can be approximately <NUM>.

The pitch of each wire forming the first braid <NUM> is preferably <NUM> to <NUM>, and can be <NUM> or larger.

The pitch of each wire forming the first braid <NUM> is preferably less than twice the outer diameter of the distal portion (for example, the distal side small diameter region <NUM>) of the catheter body <NUM>. In this manner, bendability of the distal portion of the catheter body <NUM> can be satisfactorily achieved.

In a rectangular cross-sectional dimension of each wire (first wire <NUM> to eighth wire <NUM>) forming the second braid <NUM>, a short side is preferably <NUM> to <NUM>, and a long side is preferably <NUM> to <NUM>.

The pitch of each wire forming the second braid <NUM> is preferably <NUM> to <NUM>.

Next, examples of the material of each portion of the catheter <NUM> will be described.

As the material of the inner layer <NUM> and the inner layer <NUM>, a resin material such as PTFE can be used.

As the material of the outer layer <NUM> and the outer layer <NUM>, a nylon-based elastomer, a urethane-based elastomer, a polyester-based elastomer, or a fluorine-based resin (for example, e-PTFE) can be used. A radiopaque additive such as BaSO4 may be added to the resin material forming the outer layer <NUM> and the outer layer <NUM>. The content of the additive is appropriately determined in accordance with desired physical properties such as hardness. For example, the content can be set to <NUM>% by mass to <NUM>% by mass, based on the total mass of the resin material forming the outer layer <NUM> and the outer layer <NUM>.

The material of the marker <NUM> is not particularly limited as long as the material is a radiopaque metal material (for example, a platinum alloy).

As the material of each wire (first wire <NUM> to eighth wire <NUM>) forming the first braid <NUM>, for example, tungsten can be used.

As the material of each wire (first wire <NUM> to eighth wire <NUM>) forming the second braid <NUM>, for example, stainless steel (SUS304) can be used.

Next, a gripping portion <NUM> disposed on the proximal side of the catheter body <NUM> will be described. As shown in <FIG>, the gripping portion <NUM> is disposed in the proximal portion of the catheter body <NUM>. The gripping portion <NUM> has a connecting portion <NUM> for inserting an injector (syringe, not shown) from a proximal end thereof. A screw groove is formed on the outer periphery of the connecting portion <NUM> so that the syringe can be detachably fixed thereto. A hub <NUM> is disposed in a central portion of the gripping portion <NUM>. A hollow portion is formed in the gripping portion <NUM> so as to penetrate the gripping portion <NUM> in the axial direction from the distal end to the proximal end, and the proximal portion of the catheter body <NUM> is inserted into the distal side portion in the hollow portion. The proximal portion of the catheter body <NUM> is fixed to the gripping portion <NUM>. The hub <NUM> has two wing portions <NUM> facing each other via the axis of the gripping portion <NUM>. The wing portion <NUM> is rotated around the axis of the gripping portion <NUM>. In this manner, a torque operation for axially rotating the whole catheter body <NUM> can be performed, and an orientation of the distal end of the catheter body <NUM> entering the body cavity can be adjusted.

A protector <NUM> is disposed on the distal side of the hub <NUM> and covers the periphery of the proximal portion of the catheter body <NUM>.

For example, the catheter <NUM> is a flow direct catheter that moves forward by riding on a blood flow.

The catheter <NUM> is typically used to perform a medical procedure as follows. The catheter <NUM> is inserted into the body from a femoral base artery of a subject. The distal portion of the catheter body <NUM> is inserted into the perforator bifurcated from the internal carotid artery via the heart and the internal carotid artery. Therefore, the catheter body <NUM> is manufactured to have a length corresponding to this medical procedure. However, the present invention is not limited to this example, and the catheter <NUM> may be manufactured to have a length suitable for inserting the catheter <NUM> into other sites.

Next, a second embodiment will be described with reference to <FIG>.

The catheter according to the present embodiment (all are not shown) is different from the catheter <NUM> according to the first embodiment in a structure of the distal tip <NUM>, and the other configurations are the same as those of the catheter <NUM> according to the first embodiment.

In a case of the present embodiment, the distal tip <NUM> has a first constant diameter region <NUM> whose outer diameter and inner diameter are constant regardless of a position of the distal tip <NUM> in the axial direction, a reduced diameter region <NUM> connected to the distal side of the first constant diameter region <NUM> and whose outer diameter and the inner diameter are reduced toward the distal side, and a second constant diameter region <NUM> connected to the distal side of the reduced diameter region <NUM> and whose outer diameter and inner diameter are constant regardless of the position of the distal tip <NUM> in the axial direction.

The outer diameter and the inner diameter of the first constant diameter region <NUM> are the same as the outer diameter and the inner diameter of the distal tip <NUM> according to the first embodiment.

A fact that the outer diameter and the inner diameter of the first constant diameter region <NUM> are constant regardless of the position of the distal tip <NUM> in the axial direction means that a change in the outer diameter and a change in the inner diameter of the first constant diameter region <NUM> which correspond to the position of the distal tip <NUM> in the axial direction respectively fall within a range of ± <NUM>%, and each of the changes preferably falls within a range of ± <NUM>%.

The outer diameter and the inner diameter of the proximal end of the reduced diameter region <NUM> are equal to the outer diameter and the inner diameter of the distal end of the first constant diameter region <NUM>.

The outer diameter and the inner diameter of the reduced diameter region <NUM> are gradually reduced toward the distal side.

The outer diameter and the inner diameter of the proximal end of the second constant diameter region <NUM> are equal to the outer diameter and the inner diameter of the distal end of the reduced diameter region <NUM>.

A fact that the outer diameter and the inner diameter of the second constant diameter region <NUM> are constant regardless of the position of the distal tip <NUM> in the axial direction means that a change in the outer diameter and a change in the inner diameter of the second constant diameter region <NUM> which correspond to the position of the distal tip <NUM> in the axial direction respectively fall within a range of ± <NUM>%, and each of the changes preferably falls within a range of ± <NUM>%.

A corner portion on the outer peripheral side of the distal end of the second constant diameter region <NUM> may have an R-chamfered shape. In this case, except for a distal region where the corner portion has the R-chamfered shape in the axial direction of the second constant diameter region <NUM>, the outer diameter of the second constant diameter region <NUM> is constant regardless of the position of the distal tip <NUM> in the axial direction.

According to the present embodiment, the inner diameter of the second constant diameter region <NUM> of the distal tip <NUM> is smaller than the inner diameter of the first constant diameter region <NUM>. Accordingly, when a medical procedure is performed using the guide wire <NUM>, it is possible to reduce a clearance between the inner peripheral surface of the second constant diameter region <NUM> and the outer peripheral surface of the guide wire <NUM>.

In this manner, a variation (fluctuation) in the relative position between the guide wire <NUM> and the distal tip <NUM> can be suppressed, and a highly accurate medical procedure can be stably performed.

When a liquid such as a drug solution is discharged from the distal opening <NUM> of the distal tip <NUM> through the lumen <NUM> and the distal lumen <NUM> of the catheter, the inner diameter of the second constant diameter region <NUM> is temporarily enlarged due to the pressure of the liquid, and the liquid can be smoothly discharged.

The outer diameter of the second constant diameter region <NUM> is preferably smaller than the inner diameter of the first constant diameter region <NUM>.

However, the outer diameter of the second constant diameter region <NUM> may be equal to the inner diameter of the first constant diameter region <NUM>, or may be larger than the inner diameter of the first constant diameter region <NUM>.

In a case of the present embodiment, the inner diameter of the second constant diameter region <NUM> is equal to the outer diameter of the distal portion of the guide wire <NUM>.

Here, a set (kit) of the catheter and the guide wire <NUM> according to the present embodiment is a catheter kit according to the present embodiment.

That is, the catheter kit according to the present embodiment includes an inactive type microcatheter and the guide wire <NUM>. The catheter includes the elongated catheter body <NUM> (refer to <FIG>) having the resin layer <NUM> including the inner layer <NUM> having the lumen <NUM> and the outer layer <NUM> formed in the outer periphery of the inner layer <NUM>, and the reinforcement layer <NUM> incorporated in the resin layer <NUM> and disposed around the lumen31, the ring-shaped marker <NUM> (refer to <FIG>) made of a radiopaque metal material, the marker <NUM> being incorporated in the resin layer <NUM> in the distal end of the catheter body <NUM>, fixed to the distal end of the reinforcement layer <NUM>, and disposed around the lumen <NUM>, and the resin-made distal tip (refer to <FIG>) linked to the distal end of the catheter body <NUM>, the distal tip <NUM> having the distal lumen <NUM> communicating with the lumen <NUM> and having the open distal end, in which the outer diameter of the distal end of the catheter body <NUM> is <NUM> or smaller and the maximum outer diameter of the distal tip is <NUM> or smaller. The dimension of the marker <NUM> in the axial direction of the catheter body <NUM> is smaller than the outer diameter of the distal tip <NUM>. The length of the distal tip <NUM> in the axial direction of the distal tip <NUM> is <NUM> to <NUM> times the maximum outer diameter of the distal tip <NUM>. In the catheter, the distal tip <NUM> has the first constant diameter region <NUM> whose outer diameter and inner diameter are constant regardless of the position of the distal tip <NUM> in the axial direction, the reduced diameter region <NUM> connected to the distal side of the first constant diameter region <NUM> and whose outer diameter and inner diameter are reduced toward the distal side, and the second constant diameter region <NUM> connected to the distal side of the reduced diameter region <NUM> and whose outer diameter and the inner diameter are constant regardless of the position of the distal tip <NUM> in the axial direction. The guide wire <NUM> is used with a diameter region <NUM>, and a catheter having a guide wire <NUM> used by being inserted into the lumen <NUM>. The inner diameter of the second constant diameter region <NUM> is equal to the outer diameter of the distal portion of the guide wire <NUM>.

According to this catheter kit, the inner diameter of the second constant diameter region <NUM> is equal to the outer diameter of the distal portion of the guide wire <NUM>. Accordingly, when a medical procedure is performed using the guide wire <NUM>, it is possible to extremely reduce a clearance between the inner peripheral surface of the second constant diameter region <NUM> and the outer peripheral surface of the guide wire <NUM>.

In this manner, a variation (fluctuation) in the relative position between the guide wire <NUM> and the distal tip <NUM> can be further suppressed, and a highly accurate medical procedure can be more stably performed.

In addition, without being limited to a case where the catheter according to the present embodiment is used in combination with the guide wire <NUM> of the above-described catheter kit, the catheter according to the present embodiment may be used in combination with a single product of the guide wire <NUM> which is not included in the kit (guide wire <NUM> distributed separately from the catheter according to the present embodiment).

Hitherto, each embodiment has been described with reference to the drawings. However, the embodiments are merely examples of the present invention, and various configurations other than those described above can be adopted.

Next, an example will be described to describe the present invention in more detail. However, the present invention is not limited by the following examples.

An intravascular surgery simulator (blood vessel model) including a simulated internal carotid artery <NUM> (<FIG>) and a simulated perforator <NUM> (<FIG>) is used so as to perform a medical procedure of causing the catheter <NUM> according to the first embodiment to enter the perforator <NUM>.

The inner diameter of the internal carotid artery <NUM> is approximately <NUM>. The perforator <NUM> is bifurcated from the internal carotid artery <NUM>. The inner diameter of the perforator <NUM> is approximately <NUM> to <NUM>.

First, as shown in <FIG>, the catheter <NUM> is moved ahead, and the guide wire <NUM> is caused to enter the perforator <NUM> from the internal carotid artery <NUM>. The distal end of the guide wire <NUM> is caused to reach a sufficiently deep position in the perforator <NUM>. The distal end of the distal tip <NUM> is not yet caused to enter the perforator <NUM>, and is located inside the internal carotid artery <NUM>.

Here, the guide wire <NUM> comes into contact with an inner peripheral wall of the internal carotid artery <NUM> at a contact point P1, obtains a reaction force from the contact point P1, and enters the perforator <NUM> bifurcated to a side facing the contact point P1. On the other hand, the distal end of the catheter <NUM>, that is, the distal end of the distal tip <NUM> does not yet reach the contact point P1 in a stage shown in <FIG>.

Next, as shown in <FIG>, the catheter <NUM> is pushed along the guide wire <NUM>, and is moved forward. In a stage shown in <FIG>, the distal end of the distal tip <NUM> exceeds the contact point P1, and is located in the vicinity of the contact point P1. In addition, the marker <NUM> does not yet reach the contact point P1.

A portion of the guide wire <NUM> which is located between the contact point P1 and the perforator <NUM> is bent by a slight force. However, according to the present embodiment, the distal tip <NUM> is configured to be sufficiently soft (Shore D hardness is <NUM> or higher and <NUM> or lower). Therefore, bending of the guide wire <NUM> can be suppressed when the distal tip <NUM> moves forward along the guide wire <NUM>.

Next, as shown in <FIG> and <FIG>, the catheter <NUM> is further pushed along the guide wire <NUM>, and is further moved forward. In a stage shown in <FIG> and <FIG>, the distal end of the distal tip <NUM> enters the perforator <NUM>. In addition, the marker <NUM> exceeds the contact point P1.

According to the present embodiment, the length of the distal tip <NUM> in the axial direction is <NUM>, the maximum outer diameter of the distal tip <NUM> is <NUM>, and the length of the marker <NUM> in the axial direction of the catheter body <NUM> is <NUM>. The sufficiently soft distal tip <NUM> has a sufficient length (<NUM> times or more the maximum outer diameter of the distal tip <NUM>), and the marker <NUM> is sufficiently short (dimension of the marker <NUM> in the axial direction of the catheter body <NUM> is smaller than the maximum outer diameter of the distal tip <NUM>). Accordingly, in a process of causing the distal end of the distal tip <NUM> to enter the perforator <NUM>, the bending caused by a fact that the portion of the guide wire <NUM> which is located between the contact point P1 and the perforator <NUM> is pressed by the catheter <NUM> is suppressed. That is, when the marker <NUM> exceeds the contact point P1 or after the marker <NUM> exceeds the contact point P1 as shown in <FIG> and <FIG>, it is possible to suppress a force of the marker <NUM> to press the portion located between the contact point P1 and the perforator <NUM> in the guide wire <NUM> upward (in a direction of an arrow A) in <FIG> and <FIG>. Therefore, while the distal tip <NUM> is caused to satisfactorily follow a bent shape of the guide wire <NUM>, the distal tip <NUM> can enter the perforator <NUM> along the guide wire <NUM>.

In addition, the reinforcement layer <NUM> disposed in the distal portion of the catheter body <NUM> is configured to include the braid (first braid <NUM>) in which the wires are braided, and the pitch of the wires is <NUM>. The outer diameter of the distal portion of the catheter body <NUM> is <NUM>. That is, in the portion of the catheter body <NUM> which is connected to the proximal side of the marker <NUM>, the pitch of the wires forming the first braid <NUM> is set to be less than twice the outer diameter of the distal portion of the catheter body <NUM>.

In this manner, as shown in <FIG> and <FIG>, when the catheter <NUM> moves forward while the portion connected to the proximal side of the marker <NUM> in the catheter body <NUM> comes into contact with the contact point P1, the portion of the catheter body <NUM> which comes into contact with the contact point P1 can be smoothly bent.

That is, the catheter body <NUM> has the first braid <NUM>. Accordingly, although bending rigidity of the catheter body <NUM> is higher than bending rigidity of the distal tip <NUM>, the pitch of the wires of the first braid <NUM> is sufficiently small. Therefore, the first braid <NUM> and the catheter body <NUM> can be smoothly bent by a reaction force received from the contact point P1. In particular, the cross-sectional shape of the wire forming the first braid <NUM> is circular. Accordingly, the wires can be easily and slightly rotated (rolled) at an intersection point of the wires. Therefore, the first braid <NUM> and the catheter body <NUM> can be more smoothly bent.

Therefore, it is possible to suppress the force of the catheter body <NUM> to press the portion of the guide wire <NUM> which is located between the contact point P1 and the perforator <NUM> upward (in a direction of an arrow B shown in <FIG>) in <FIG> and <FIG>.

As a result, as shown in <FIG>, the distal end of the catheter body <NUM>, that is, a disposition region of the marker <NUM> can smoothly enter the perforator <NUM>.

As in Example <NUM>, the intravascular surgery simulator (blood vessel model) including the simulated internal carotid artery <NUM> (<FIG>) and the simulated perforator <NUM> (<FIG>) is used to perform the medical procedure of causing the catheter <NUM> according to the first embodiment to enter the perforator <NUM>.

First, as shown in <FIG>, the catheter <NUM> is moved ahead, and the guide wire <NUM> is caused to enter the perforator <NUM> from the internal carotid artery <NUM>. The distal end of the guide wire <NUM> is caused to reach the vicinity of the entrance of the perforator <NUM>. The distal end of the distal tip <NUM> is not yet caused to enter the perforator <NUM>, and is located inside the internal carotid artery <NUM>.

Next, as shown in <FIG>, the catheter <NUM> is pushed along the guide wire <NUM>, and is moved forward. In a stage shown in <FIG>, the distal end of the distal tip <NUM> enters the perforator <NUM>, and the marker <NUM> exceeds the contact point P1.

As in Example <NUM>, when the marker <NUM> exceeds the contact point P1 or after the marker <NUM> exceeds the contact point P1, the force of the marker <NUM> to press the portion located between the contact point P1 and the perforator <NUM> in the guide wire <NUM> upward (direction of the arrow A) in <FIG> and <FIG> or the force of the catheter body <NUM> to press the portion upward (direction of the arrow B) in <FIG> and <FIG> is suppressed. Accordingly, as shown in <FIG>, the distal end of the catheter body <NUM> can smoothly enter the perforator <NUM>.

As a microcatheter (hereinafter, a catheter <NUM>: <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>), a commercially available microcatheter having relatively good vascular selectivity is representatively used. As in Example <NUM>, the intravascular surgery simulator including the simulated internal carotid artery <NUM> and the simulated perforator <NUM> is used to perform the medical procedure of causing the catheter <NUM> to enter the perforator <NUM>.

In the catheter <NUM>, the length of the distal tip <NUM> in the axial direction is smaller than one time the maximum outer diameter of the distal tip <NUM>, and the length of the marker <NUM> in the axial direction of the catheter body <NUM> is larger than the maximum outer diameter of the distal tip <NUM>. Compared to the catheter <NUM> according to the present embodiment, a length ratio of a distal tip <NUM> is significantly decreased, and a length ratio of a marker <NUM> is increased. In addition, a structure is adopted in which the reinforcement layer extends from the marker <NUM> toward the proximal side.

In a stage shown in <FIG>, as in the stage shown in <FIG>, the catheter <NUM> is moved ahead, and the guide wire <NUM> enters the perforator <NUM> from the internal carotid artery <NUM>. The distal end of the distal tip <NUM> is not yet caused to enter the perforator <NUM>, is located inside the internal carotid artery <NUM>, and does not yet reach the contact point P1.

The catheter <NUM> has a structure as follows. The marker <NUM> is located in the vicinity of the distal end of the catheter <NUM>, the axial length of the marker <NUM> is long, the reinforcement layer extends from the marker <NUM> toward the proximal side, and the rigidity is improved up to the vicinity of the distal end of the catheter <NUM>.

Therefore, when the catheter <NUM> is pushed along the guide wire <NUM> from the stage shown in <FIG>, a portion of the guide wire <NUM> which is located between the contact point P1 and the perforator <NUM> is pressed against the distal portion of the catheter <NUM>, and is bent. In some cases, the guide wire <NUM> is separated from the perforator <NUM>.

In addition, in some cases, the distal portion of the catheter <NUM> is caught on the inner peripheral surface of the internal carotid artery <NUM> at the contact point P1, and is not moved forward any further.

In addition, as shown in <FIG>, in a case where the catheter <NUM> is pushed along the guide wire <NUM> and the distal end of the distal tip <NUM> can enter the vicinity of the entrance of the perforator <NUM>, as described below, the catheter <NUM> cannot more deeply enter the perforator <NUM>, or the guide wire <NUM> and the catheter <NUM> are eventually separated from the perforator <NUM>, in some cases.

That is, as shown in <FIG>, after the distal end of the distal tip <NUM> enters the vicinity of the entrance of the perforator <NUM>, even if the catheter <NUM> is further pushed as shown in <FIG> and <FIG>, the distal portion of the catheter <NUM> is caught on the vicinity of the entrance of the perforator <NUM>, and the catheter body <NUM> is bent in the direction of the arrow B in <FIG> and <FIG>. In this case, the distal portion of the guide wire <NUM> is gradually drawn into the catheter <NUM>.

The reason for the operation is considered as follows. The distal tip <NUM> which is a soft portion of the distal portion of the catheter <NUM> is short. Accordingly, the distal portion of the catheter <NUM> is stiffened, protruded, and caught on the wall surface of the entrance of the perforator <NUM>.

Furthermore, the flexibility of the distal portion of the catheter <NUM> is poor. Accordingly, in a state where the distal portion of the catheter <NUM> is bent, the force of pushing the catheter <NUM> is applied in a forward moving direction of the catheter <NUM> on the proximal side of the bent portion. Accordingly, there is a high ratio that the pushing force is consumed in the lateral movement (direction intersecting the longitudinal direction) instead of the vertical movement (longitudinal direction) of the distal portion. This fact is also considered as the reason of the operation shown in <FIG> and <FIG>.

When the catheter <NUM> is further pushed thereafter, as shown in <FIG>, the catheter <NUM> once entering the vicinity of the entrance of the perforator <NUM> falls off from the perforator <NUM>, and is further pushed in the direction of the arrow B inside the internal carotid artery <NUM>.

Claim 1:
A catheter (<NUM>) comprising:
a catheter body (<NUM>) having a resin layer (<NUM>) including an inner layer (<NUM>) having a lumen (<NUM>) and an outer layer (<NUM>) formed in an outer periphery of the inner layer (<NUM>), and a reinforcement layer (<NUM>) incorporated in the resin layer (<NUM>) and disposed around the lumen (<NUM>) and around the inner layer (<NUM>) so as to surround the inner layer (<NUM>);
a ring-shaped marker (<NUM>) made of a radiopaque metal material, the marker (<NUM>) being incorporated in the resin layer (<NUM>) in a distal end of the catheter body (<NUM>), fixed to a distal end of the reinforcement layer (<NUM>), and disposed around the lumen (<NUM>); and
a distal tip (<NUM>) made of a resin linked to the distal end of the catheter body (<NUM>), the distal tip (<NUM>) having a distal lumen (<NUM>) which communicates with the lumen (<NUM>) and has an open distal end (<NUM>),
wherein an outer diameter of the distal end of the catheter body (<NUM>) is <NUM> or smaller, and a maximum outer diameter of the distal tip (<NUM>) is <NUM> or smaller, and
characterized in that
the reinforcement layer (<NUM>) is configured to include a first braid (<NUM>) and a second braid (<NUM>) disposed in an outer periphery of the first braid (<NUM>),
wherein the first braid (<NUM>) is continuously disposed from the distal end to a proximal end of the catheter body (<NUM>) and wherein the second braid (<NUM>) is continuously disposed from an intermediate portion to the proximal end of the catheter body (<NUM>) but is not disposed in a distal portion of the catheter body (<NUM>),
the distal tip (<NUM>) has a Shore D hardness, as measured according to ISO686, of <NUM> to <NUM>,
a dimension of the marker (<NUM>) in an axial direction of the catheter body (<NUM>) is smaller than a maximum outer diameter of the distal tip (<NUM>), and
a length of the distal tip (<NUM>) in the axial direction of the distal tip (<NUM>) is <NUM> times to <NUM> times the maximum outer diameter of the distal tip (<NUM>).