Patent Description:
When a catheter is inserted into a body lumen, a guide wire is used to guide the catheter to a region of interest in the body lumen. The guide wire is formed to be insertable into the catheter along an axial direction thereof, is inserted into the body lumen prior to the catheter, and guides insertion of the catheter. The guide wire is also used to guide an endoscope.

The guide wire, which is used in a catheter for treatment of a stenosis of a blood vessel is required to have excellent penetrability for approaching the stenosis of the blood vessel. Particularly in a case where the blood vessel has severe stenosis such as chronic total occlusion, it is necessary to improve the penetrability of the guide wire because a distal end portion of the guide wire slips on a surface of the stenosis to make it difficult for the distal end portion to approach the stenosis.

To improve the penetrability of the guide wire, there is known a technique, as disclosed in, for example, PTL1, for providing a tip having a tapered portion narrower in diameter toward a distal end of the tip in the distal end portion of the guide wire, and forming the distal end of the tip into a circular arc shape.

When the blood vessel has severe stenosis and particularly when the blood vessel is completely blocked, there is a probability that the sufficient penetrability cannot be ensured even for the guide wire contrived as described above. This is because the distal end portion of the guide wire slips on the surface of the stenosis and is not caught on the surface of the stenosis. Furthermore, manipulation time is often prolonged because the penetrability of the guide wire cannot be sufficiently ensured to make it difficult for the guide wire to approach the stenosis.

PLT1 also discloses a technique for providing a plane section on the distal end of the guide wire and forming a recess in the plane section, thereby improving the penetrability. In this case, however, there is present the plane section that faces a direction of forward movement of the guide wire and this plane section comes in surface contact with an interior of the body lumen. As a result, the passing performance of the guide wire within the body lumen possibly degrades.

The present disclosure has been made to address the abovementioned problems and an object of the present invention is to provide a guide wire capable of exhibiting improved penetrability for penetrating a stenosis without degradation of passing performance of the guide wire.

In order to solve the above-mentioned problem, the present invention provides a guide wire according to independent claim <NUM>. The dependent claims relate to advantageous embodiments.

The guide wire configured as described above can suppress the slipping of the distal end portion on a stenosis by the recesses and improve the penetrability of the guide wire while improving the passing performance of the guide wire within the body lumen by the curved distal end portion.

Forming the recesses in the top portion and the surrounding portion, respectively can suppress the slipping even when the distal end portion of the guide wire does not move straight into the stenosis.

Forming the plurality of recesses along the circumferential direction of the surrounding portion can suppress the slipping on the stenosis irrespective of the circumferential orientation of the guide wire.

Making the recesses formed in the surrounding portion identical in shape and disposing the recesses equidistantly along the circumferential direction can make constant an effect of suppressing the slipping on the stenosis irrespective of the circumferential orientation of the guide wire.

Forming a plurality of rows of the recesses along an axial direction of the surrounding portion can suppress the slipping of the distal end portion on the stenosis in a wider range.

Forming a circular distal recess in the top portion and forming circular or oval surrounding recesses in the surrounding portion can ensure suppression of the slipping because the edge of the distal recess or each surrounding recess is caught on the stenosis at whichever angle the guide wire comes in contact with the stenosis.

Configuring the surrounding recess to be oval and disposing the surrounding recess such that a long axis faces along the circumferential direction of the surrounding portion and a short axis faces along the axial direction of the surrounding portion can elongate the edge of each surrounding recess in a direction orthogonal to a slipping direction and increase a resistance force against the slipping when the distal end portion of the guide wire slips against an axial force.

Embodiments of the present invention will be described hereinafter with reference to the drawings. It is noted that a scale ratio of the drawings is exaggerated for the convenience of description and often differs from an actual scale ratio. In the present description, a side of a catheter <NUM> inserted into a body lumen will be referred to as "distal end" or "distal side" while a handling hand side thereof will be referred to as "proximal end" or "proximal side". Furthermore, each figure schematically shows a guide wire <NUM> while a length direction thereof is reduced and a thickness direction thereof is exaggerated, so that a ratio of the length direction to the thickness direction differs from an actual ratio.

First, a configuration of the catheter <NUM> using the guide wire <NUM> according to a present embodiment will be described. As shown in <FIG>, the catheter <NUM> using the guide wire <NUM> according to the present embodiment includes an elongated and hollow catheter main body portion <NUM>, a balloon <NUM> provided on a distal end portion of the catheter main body portion <NUM>, and a hub <NUM> fixedly bonded to a proximal end of the catheter main body portion <NUM>.

The catheter main body portion <NUM> includes an outer tube <NUM> that is a hollow tube-shaped body and an inner tube <NUM> that is a hollow tube-shaped body disposed within the outer tube <NUM>. A dilation lumen <NUM> in which a dilation fluid for dilating the balloon <NUM> circulates is formed between the outer tube <NUM> and the inner tube <NUM>, and a guide wire lumen <NUM> into which the guide wire <NUM> is inserted is formed inside the inner tube <NUM>.

Preferably, the outer tube <NUM> and the inner tube <NUM> are each formed from a material exhibiting a certain degree of flexibility. Examples of such a material to be used include polyolefin such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, and mixtures of two or more types of the above polymers, fluorocarbon resin such as soft polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, and polytetrafluoroethylene, silicone rubber, and latex.

A distal side of the balloon <NUM> is adhesively bonded to the inner tube <NUM>, a proximal side thereof is adhesively bonded to the outer tube <NUM>, and an interior of the balloon <NUM> is in communication with the dialation lumen <NUM>. It is thereby possible to dilate the balloon <NUM> by injecting the dilation fluid into the balloon <NUM> via the dilation lumen <NUM>. The dilation fluid may be either a gas or a liquid, and the gas such as helium gas, CO<NUM> gas, or O<NUM> gas, or the liquid such as a physiological salt solution or a contrast agent can be used as the dilation fluid.

The hub <NUM> includes a first opening portion <NUM> that functions as a port which communicates with the dilation lumen <NUM> formed between the outer tube <NUM> and the inner tube <NUM> and into or out of which the dilation fluid flows, and a second opening portion <NUM> that communicates with the guide wire lumen <NUM>. A hemostasis valve <NUM> inhibiting outflow of blood while the guide wire <NUM> is allowed to be freely inserted into the hemostasis valve <NUM> is provided in the second opening portion <NUM>.

During a treatment, the guide wire <NUM> is inserted into the catheter <NUM> from the second opening portion <NUM> up to a distal end of the catheter main body portion <NUM> through the guide wire lumen <NUM>. Furthermore, a distal end of the guide wire <NUM> protrudes further to a distal side than the distal end of the catheter main body portion <NUM>. It is noted that the distal end of the guide wire <NUM> and a vicinity of the distal end thereof are slightly curved. During manipulation, the catheter main body portion <NUM> is inserted into the body lumen while the guide wire <NUM> is inserted thereinto earlier than the catheter main body portion <NUM>.

The guide wire <NUM> according to the first embodiment will be described in detail. The guide wire <NUM> includes a wire main body <NUM> formed into an elongated linear shape. The wire main body <NUM> is an elastic wire rod and formed by winding a wire around a core wire. The core wire and the wire are formed from a metal material such as stainless steel. It is noted that the wire main body <NUM> may be formed from resin.

An entire length of the guide wire <NUM> is, in general, but not exclusively, about <NUM> to <NUM>. Similarly, an outer diameter of the core wire is preferably, but not exclusively, in a range from <NUM> to <NUM>. Similarly, an outer diameter of the guide wire <NUM> is, in general, but not exclusively, about <NUM> to <NUM>. In the present embodiment, a load acting on the distal end of the guide wire <NUM> is in a range from <NUM> to <NUM> gf.

No wire is wound around a distal end portion <NUM> of the wire main body <NUM> but a tip is provided on the distal end portion <NUM>. The tip is formed from a solder, silver, gold, or the like, or is formed from resin when the wire main body <NUM> is formed from resin. Preferably, a diameter of the tip is in a range from <NUM> to <NUM> and a length of the tip is in a range from <NUM> to <NUM>. This distal end portion <NUM> will be described in more detail. As shown in <FIG>, the distal end portion <NUM> of the wire main body <NUM> is formed into a smooth curved surface by a top portion <NUM> that forms an extreme distal portion of the wire main body <NUM> and a surrounding portion <NUM> that makes the top portion <NUM> continuous with a peripheral surface <NUM> of the wire main body <NUM>. In the present embodiment, the distal end portion <NUM> is formed to have a hemispherical surface. However, a shape of the distal end portion <NUM> is not limited to a hemispherical shape but may be either a spherical shape or an aspherical rounded shape such that the peripheral surface <NUM> is continuous with the top portion <NUM>.

A plurality of recesses are formed in the distal end portion <NUM> of the wire main body <NUM>. Out of the recesses, a circular distal recess <NUM> is formed in the top portion <NUM>. Furthermore, a plurality of circular surrounding recesses <NUM> are formed in the surrounding portion <NUM>. The plurality of surrounding recesses <NUM> are formed in a circumferential direction to form a row and a plurality of the rows are provided in an axial direction. In each row of the surrounding recesses <NUM> along the circumferential direction, the surrounding recesses <NUM> are identical in shape and disposed equidistantly in the circumferential direction. It is noted that being identical in shape signifies being identical in shape despite a difference in magnitude.

The surrounding recesses <NUM> differ in diameter in the axial direction. The surrounding recesses <NUM> are formed such that those closer to the top portion <NUM> have larger diameters and those closer to the peripheral surface <NUM> have smaller diameters. The surrounding recesses <NUM> closer to the peripheral surface <NUM> are disposed to be narrowly spaced in the circumferential direction, as compared with the surrounding recesses <NUM> closer to the top portion <NUM>.

As shown in <FIG>, each of the distal recess <NUM> and the surrounding recesses <NUM> is formed to extend in a direction orthogonal to a direction of being tangential to a central position of each recess with the diameter kept unchanged. That is, the distal recess <NUM> and the surrounding recesses <NUM> within the guide wire <NUM> are all columnar. Moreover, any of the recesses is formed as a recess which has the same depth and which is circular in a view from the direction orthogonal to the direction of being tangential to the central position of each recesses. An edge 35a is formed in an edge portion of the distal recess <NUM> along the circumferential direction while an edge 36a is similarly formed in an edge portion of each surrounding recess <NUM> along the circumferential direction.

Since the distal end portion <NUM> of the guide wire <NUM> having the distal recess <NUM> and the surrounding recesses <NUM> is formed into the curved shape, the guide wire <NUM> is allowed to move forward smoothly without surface-contact of the distal end portion <NUM> with a blood vessel wall and the like. On the other hand, as shown in <FIG>, in a case where an interior of a blood vessel <NUM> is fully blocked by a stenosis <NUM>, the curved distal end portion <NUM> of the guide wire <NUM> is to slip, for example, in an S direction in <FIG> when striking against a surface of the stenosis <NUM>. To address this slipping, the distal recess <NUM> and the surrounding recesses <NUM> are formed in the distal end portion <NUM> of the guide wire <NUM>, whereby the edges 35a and 36a of those recesses <NUM> and <NUM> are caught on the surface of the stenosis <NUM> to suppress slipping of the distal end portion <NUM>. It is thereby possible to cause the guide wire <NUM> to move forward in a P direction which is a direction of forward movement in <FIG>. That is, it is possible to improve penetrability of the guide wire <NUM> for penetrating the stenosis <NUM> while maintaining excellent passing performance of the guide wire <NUM>.

Moreover, when a high lubricity coating is applied onto the distal end portion <NUM> of the guide wire <NUM> for improving the passing performance, the distal end portion <NUM> becomes particularly slippery. Therefore, it is possible to exhibit more effectively a function to suppress the slipping of the distal end portion <NUM> on the stenosis <NUM> by forming the recesses in the distal end portion <NUM>.

Even when the stenosis <NUM> does not completely block the blood vessel <NUM> differently from <FIG>, it is often difficult for the guide wire <NUM> to move forward into the stenosis <NUM>. Even in that case, similarly to the above, it is possible to achieve the effect of improving the penetrability according to the present invention.

A direction in which the distal end portion <NUM> of the guide wire <NUM> slips varies, depending on an orientation of the guide wire <NUM>, a surface state of the stenosis <NUM>, a direction of a force acting on the guide wire <NUM> or the like, so that the distal end portion <NUM> is likely to slip in whatever direction. To address this slipping, the surrounding recesses <NUM> are disposed equidistantly in the circumferential direction, so that it is possible to suppress the slipping of the distal end portion <NUM> of the guide wire <NUM> in whatever direction.

Furthermore, each recess is formed to extend in the direction orthogonal to the direction of being tangential to the central position of the recess. Therefore, the edges 35a and 36a are caught on the surface of the stenosis <NUM> in the same way in whatever direction when each recess comes in contact with the stenosis <NUM>. It is, therefore, possible to exhibit a sufficient slipping suppressing effect in whatever direction.

The disposition of the distal recess <NUM> and the surrounding recesses, recess diameters, the numbers, and depths can be set as appropriate and are not limited to specific ones. Preferably, however, the recess diameters are in a range from <NUM> to <NUM>, the number of the recesses is one in the top portion <NUM> and two to five rows of five to ten surrounding recesses in the surrounding portion <NUM>, and the depths are in a range from <NUM> to <NUM>.

Various methods may be conceivable as a manufacturing method for forming the distal recess <NUM> and the surrounding recesses <NUM> in the distal end portion <NUM>. For example, the distal recess <NUM> and the surrounding recesses <NUM> can be formed by forming recesses in the distal end portion <NUM> of the wire main body <NUM> by means of a fine drill. Alternatively, a method may be conceivable for forming recesses by locally applying a heat to a surface of the distal end portion <NUM>. As for the distal recess <NUM>, at a time of working the distal end portion <NUM> of the wire main body <NUM> into the curved shape by a rotary grindstone, a protruding portion is formed on the grindstone and the distal recess <NUM> can be formed by this protruding portion. In another alternative, a method may be conceivable for forming recesses by means of a die having an opposite shape to the shape of the distal end portion <NUM>.

In the present embodiment, each of the recesses is formed to extend from the surface of the distal end portion <NUM> in a perpendicular direction as shown in <FIG>. Alternatively, as shown in <FIG>, each of surrounding recesses <NUM> may be formed to extend in a direction from the distal side to the proximal side of the guide wire <NUM> (axial direction of the guide wire <NUM>). In this case, an angle of an edge 37a of each surrounding recess <NUM> varies along the circumferential direction, so that there occurs a difference in effect depending on a slipping direction of the guide wire <NUM> but it is possible to attain the effect of improving the penetrability for penetrating the stenosis <NUM>.

Other embodiments of the surrounding recesses will be described. As shown in <FIG>, surrounding recesses <NUM> may be each formed into an oval shape. In this case, the shape of each surrounding recess <NUM> within the guide wire <NUM> is an oval cylindrical shape. It is noted that the shape of the distal end portion <NUM> and that of the distal recess <NUM> in this embodiment are similar to those in the first embodiment.

The surrounding recesses <NUM> according to the present embodiment are each disposed such that a long axis faces along the circumferential direction of the surrounding portion <NUM> and a short axis faces along the axial direction of the surrounding portion <NUM>. A force acts on the guide wire <NUM> for inserting the guide wire <NUM> in the axial direction, so that the distal end portion <NUM> slips on the stenosis <NUM> along the curved shape of the distal end portion <NUM> in the axial direction. Each surrounding recess <NUM> according to the present embodiment is elongated in the direction orthogonal to the axial direction and the distal end portion <NUM> is caught on the stenosis <NUM> by a large length when the distal end portion <NUM> slips in the axial direction. Therefore, it is possible to make higher a resistance force against the slipping.

Moreover, as shown in <FIG>, surrounding recesses <NUM> may be formed into a groove shape concentric with the distal recess <NUM>. In this case, edges 39a are coupled together throughout an entire circumference. Owing to this, even when the distal end portion <NUM> slips at whatever angle, it is possible to generate a resistance force to ensure that the edges 39a are caught on the stenosis <NUM> and to suppress slipping.

As described so far, the guide wire <NUM> according to the present embodiments includes the wire main body <NUM> formed into the linear shape, the distal end portion <NUM> of the wire main body <NUM> is formed into the curved shape by the top portion <NUM> that forms the extreme distal portion and the surrounding portion <NUM> that makes the top portion <NUM> continuous with the peripheral surface <NUM> of the wire main body <NUM>, and the plurality of recesses <NUM> and <NUM> are formed in the distal end portion <NUM>. With this configuration, it is possible to suppress the slipping of the distal end portion <NUM> on the stenosis <NUM> by the recesses <NUM> and <NUM> and improve the penetrability of the guide wire <NUM> while improving the passing performance of the guide wire <NUM> within the body lumen by the curved distal end portion <NUM>.

Moreover, forming the recesses <NUM> and <NUM> in the top portion <NUM> and the surrounding portion <NUM>, respectively can suppress the slipping even when the distal end portion <NUM> of the guide wire <NUM> does not move straight into the stenosis <NUM>.

Furthermore, forming the recesses <NUM> along the circumferential direction of the surrounding portion <NUM> can suppress the slipping on the stenosis <NUM> irrespective of the circumferential orientation of the guide wire <NUM>.

Moreover, making the recesses <NUM> formed in the surrounding portion <NUM> identical in shape and disposing the recesses equidistantly along the circumferential direction can make constant the effect of suppressing the slipping on the stenosis <NUM> irrespective of the circumferential orientation of the guide wire <NUM>.

Furthermore, forming a plurality of rows of the recesses <NUM> along the axial direction of the surrounding portion <NUM> can suppress the slipping of the distal end portion <NUM> on the stenosis <NUM> in a wider range.

Further, forming the circular distal recess <NUM> in the top portion <NUM> and forming the circular or oval surrounding recesses <NUM> in the surrounding portion <NUM> can ensure suppression of the slipping because the edge 35a or 36a of the distal recess <NUM> or each surrounding recess <NUM> is caught on the stenosis <NUM> at whichever angle the guide wire <NUM> comes in contact with the stenosis <NUM>.

Moreover, configuring the surrounding recess <NUM> to be oval and disposing the surrounding recess <NUM> such that the long axis faces along the circumferential direction of the surrounding portion <NUM> and the short axis faces along the axial direction of the surrounding portion <NUM> can elongate the edge of each surrounding recess <NUM> in the direction orthogonal to a slipping direction and increase the resistance force against the slipping when the distal end portion <NUM> of the guide wire <NUM> slips against an axial force.

While the shape of the distal recess <NUM> is the circular shape and the shape of each surrounding recess is the circular shape, the oval shape, or the groove shape in the abovementioned embodiments, the shapes may be the other shapes. For example, the shapes may be a polygonal shape or may be a shape such as a star shape or a crisscross shape.

Nevertheless, the distal recess <NUM> faces to the direction of forward movement of the guide wire <NUM> and the edge 35a needs to receive the slipping of the distal end portion <NUM> from any direction when the slipping of the distal end portion <NUM> on the stenosis <NUM> occurs. Preferably, therefore, the distal recess <NUM> is the circular shape that enables the edge 35a to face in the same way at any angle.

Moreover, the shapes of the distal recess <NUM> and the surrounding recesses within the guide wire <NUM> are the columnar shape or the oval cylindrical shape according to the abovementioned embodiments, but the shapes may be the other shapes such as the spherical shape or a hemispherical shape having an aspherical surface.

Furthermore, in the abovementioned embodiments, the distal recess <NUM> is formed in the top portion <NUM> of the distal end portion <NUM> of the wire main body <NUM> and the surrounding recesses are formed in the surrounding portion <NUM>. However, it suffices to form a plurality of recesses at least in the distal end portion <NUM> and the plurality of recesses may be disposed arbitrarily without limitation.

Moreover, while the catheter <NUM> using the guide wire <NUM> according to the abovementioned embodiments is an over-the-wire type, the catheter <NUM> may be a rapid-exchange type. Furthermore, an object using the guide wire <NUM> is not limited to the catheter but may be an endoscope or the like.

Claim 1:
A guide wire (<NUM>) comprising a wire main body (<NUM>) formed into a linear shape, wherein a tip is provided on a distal end portion (<NUM>) of the wire main body (<NUM>), said distal end portion (<NUM>) being is formed into a curved shape by a top portion (<NUM>) that forms an extreme distal portion and a surrounding portion (<NUM>) that makes the top portion (<NUM>) continuous with a peripheral surface (<NUM>) of the wire main body (<NUM>), and a recess is formed in the top portion (<NUM>); and
characterized in that
recesses are formed in the surrounding portion.