Patent Description:
In recent years, treatment of the inside of a lumen such as a blood vessel by using a catheter has been actively performed since surgical invasiveness thereof is very low. The catheter generally includes a shaft including a lumen extending the shaft from a distal end to a proximal end, and a hub disposed at the proximal end of the shaft. The hub is formed with a passage communicating with the lumen in order to connect to a syringe or the like.

As a method for fixing the proximal end of the shaft to the hub, an insert molding method, a bonding method using an adhesive, and the like are known.

In an insert molding method described in PTL <NUM>, a shaft is disposed in an injection mold, a part of the shaft is pressed by a fixing pin, and a resin for a hub is injection-molded at a high temperature and a high pressure. Therefore, deformation of the shaft caused by the fixing pin or displacement of the shaft in an axial center direction may occur. The deformation of the shaft and the displacement in the axial center direction may cause a decrease in fixing strength between the shaft and the hub.

In addition, in a bonding method using an adhesive described in PTL <NUM>, if a gap between an outer diameter of a shaft and a lumen of a shaft accommodation unit of a hub is excessively small, the adhesive cannot flow therein, and the gap remains between the hub and the shaft, which may cause a decrease in fixing strength between the shaft and the hub. If the gap between the outer diameter of the shaft and the lumen of the shaft accommodation unit of the hub is excessively large, it is difficult to completely fill the gap between the hub and the shaft with the adhesive, and thus the fixing strength between the shaft and the hub may decrease.

The present invention has been made in order to solve the above-described problem, and an object thereof is to provide a catheter capable of firmly fixing a shaft and a hub.

A catheter according to the present invention that achieves the above-described object includes: a shaft that is a tubular body in which a lumen extending the shaft from a distal end to a proximal end is formed, and that includes a shaft proximal surface in which the lumen is opened and a shaft outer surface that is an outer peripheral surface of the tubular body; and a hub that is attached to the proximal end of the shaft. The hub includes a tubular accommodation unit that is configured to accommodate the shaft, the accommodation unit includes a hub welded surface that is directly welded to the shaft outer surface, and at least one of the accommodation unit and the hub is formed with a plurality of bubbles at a position close to the hub welded surface.

In the catheter configured as described above, the accommodation unit and the hub are welded so as to enter each other by bubbles. Therefore, the shaft and the hub can be firmly fixed.

The accommodation unit may be formed with a plurality of hub bubbles, which are bubbles, at a position close to the hub welded surface. Accordingly, the hub welded surface of the accommodation unit has a complicated shape with irregularities and is welded to the outer surface of the shaft. Therefore, the shaft and the hub can be firmly fixed.

The shaft may be formed with a plurality of shaft bubbles, which are bubbles, at a position close to a shaft welded surface of the shaft outer surface welded to the hub welded surface. Accordingly, the shaft outer surface has a complicated shape with irregularities and is welded to the hub welded surface. Therefore, the shaft and the hub can be firmly fixed.

Both the hub and the shaft may include a plurality of the bubbles, and the hub welded surface and the shaft welded surface of the shaft outer surface welded to the hub welded surface may have irregularities and may be welded so as to enter each other. Accordingly, the shaft and the hub can be fixed more firmly.

An embodiment according to the present invention will be described hereinafter with reference to the drawings. For convenience of description, dimensional ratios in the drawings may be exaggerated and may be different from actual ratios. In the following description, a side on which a catheter is operated will be referred to as a "proximal side", and a side to be inserted into a living body will be referred to as a "distal side".

As illustrated in <FIG>, a catheter <NUM> according to the embodiment of the present invention includes a shaft <NUM> that is an elongated tubular body, a hub <NUM> fixed to a proximal end of the shaft <NUM>, and a flexible anti-kink protector <NUM> configured to prevent bending of the shaft <NUM>. In addition to a catheter that supports a guide wire, the catheter <NUM> may be a guiding catheter, a contrast catheter, or a micro-catheter, or may be a balloon catheter including an inflation lumen or an image diagnosis catheter. In addition, the catheter <NUM> may be an over-the-wire (OTW) catheter in which a guide wire lumen extending from a distal end of the shaft to the hub is formed, or may be a rapid exchange (RX) catheter in which the guide wire lumen is formed only in a distal portion of the shaft. For example, a guide wire lumen of an RX type balloon catheter is formed from the distal end of the shaft to an opening portion in the middle in an axial center direction of the shaft. An inflation lumen through which a fluid for inflating a balloon of the RX type balloon catheter flows is formed so as to extend from the balloon to a hub at a proximal end of the catheter.

The shaft <NUM> is formed with a lumen <NUM> that extends the shaft <NUM> from a distal end to the proximal end. The shaft <NUM> includes a shaft outer surface <NUM>, a shaft inner surface <NUM>, and a shaft proximal surface <NUM>.

The shaft outer surface <NUM> is an outer surface in a radial direction of the shaft <NUM>, which is a tubular body, and extends from the distal end to the proximal end of the shaft <NUM>. The shaft outer surface <NUM> includes a shaft proximal side outer surface <NUM> extending from the proximal end toward the distal end of the shaft <NUM> to a predetermined position. The shaft proximal side outer surface <NUM> is surrounded by and accommodated in the hub <NUM>. The shaft proximal side outer surface <NUM> includes a substantially uniform outer diameter along an axial center X of the shaft <NUM>. The shaft proximal side outer surface <NUM> includes a shaft welded surface <NUM> welded to the hub <NUM>, and a shaft separated surface <NUM> that is disposed on the distal side of the shaft welded surface <NUM> and separated from the hub <NUM>. The shaft separated surface <NUM> is not welded to the hub <NUM> and is separated from the hub <NUM> with a gap therebetween. A plurality of shaft bubbles <NUM> are formed in the vicinity of the shaft welded surface <NUM> of the shaft <NUM>. Each of the shaft bubbles <NUM> includes an inner surface surrounding a closed space.

The shaft inner surface <NUM> is an inner surface in the radial direction of the shaft <NUM>, which is a tubular body, and extends from the distal end to the proximal end of the shaft <NUM>.

The shaft proximal surface <NUM> is a surface facing the proximal side at the proximal end of the shaft <NUM>, and is formed by being cut perpendicularly to the axial center X of the shaft <NUM>.

The shaft <NUM> in the present embodiment includes an inner layer <NUM> that forms the shaft inner surface <NUM>, an outer layer <NUM> that forms the shaft outer surface <NUM>, and a reinforcement body <NUM> that is embedded in the shaft <NUM>.

In addition to a polyamide resin, a polyester resin, a polyolefin resin and a polyurethane resin, examples of a constituent material of the outer layer <NUM> include a polyamide elastomer, a polyester elastomer, a polyurethane elastomer, a mixture of one or more of these examples, and a mixture of materials having different hardnesses. The outer layer <NUM> may be formed by arranging materials having different hardnesses so as to become softer from the proximal end toward the distal end.

A constituent material of the inner layer <NUM> may be the same material as the constituent material of the outer layer <NUM> described above, or may be a material different from the constituent material of the outer layer <NUM>. The constituent material of the inner layer <NUM> may be a fluorine-based resin material such as a polytetrafluoroethylene resin in order to improve slidability of an inner peripheral surface of the shaft <NUM>.

The reinforcement body <NUM> reinforces the shaft <NUM>, and is formed by braiding a plurality of reinforcement wires <NUM> into a tubular shape. In addition, the reinforcement body <NUM> may also be formed by spirally winding one or more reinforcement wires <NUM>. The material of the outer layer <NUM> or the inner layer <NUM> enters gaps between the plurality of reinforcement wires <NUM> in the reinforcement body <NUM>. The reinforcement wire <NUM> is made of a metal such as stainless steel or NiTi.

The hub <NUM> includes a tubular accommodation unit <NUM> that is disposed on the distal side and accommodates a proximal portion of the shaft <NUM>, a hub main body <NUM> that is disposed on a proximal side of the accommodation unit <NUM>, wings <NUM>, a threading projection <NUM>, and an annular projection <NUM>. In the hub <NUM>, a hub lumen <NUM> is formed which extends from a hub distal end opening <NUM> formed at a distal end of the accommodation unit <NUM> to a hub proximal end opening <NUM> formed at a proximal end of the hub main body <NUM>. The hub lumen <NUM> includes an accommodation surface <NUM> that is an inner peripheral surface of the accommodation unit <NUM>, an adjacent surface <NUM> that faces the shaft proximal surface <NUM>, and a hub passage <NUM> that is an inner peripheral surface of the hub main body <NUM>.

The accommodation surface <NUM> includes a hub welded surface <NUM> directly welded to the shaft welded surface <NUM> of the shaft proximal side outer surface <NUM>, and a hub separated surface <NUM> that is separated outward in the radial direction from the shaft separated surface <NUM> and faces the shaft separated surface <NUM>. The hub welded surface <NUM> extends from a proximal end of the accommodation surface <NUM> toward a distal direction. A proximal end of the hub welded surface <NUM> is connected to the adjacent surface <NUM>. The hub separated surface <NUM> extends in the distal direction from a distal end of the hub welded surface <NUM>. A gap between the hub separated surface <NUM> and the shaft proximal side outer surface <NUM> in the radial direction widens toward the distal direction. It should be noted that the hub separated surface <NUM> that forms the gap with the shaft proximal side outer surface <NUM> may not be provided. A plurality of hub bubbles <NUM> are formed in the vicinity of the hub welded surface <NUM> of the accommodation unit <NUM>. Each of the hub bubbles <NUM> includes an inner surface surrounding a closed space.

The adjacent surface <NUM> is an annular surface facing the distal side, and is formed substantially perpendicular to the axial center X of the shaft <NUM>. An outer side of the adjacent surface <NUM> in the radial direction is connected to the hub welded surface <NUM>. An inner side of the adjacent surface <NUM> in the radial direction is connected to a distal end of the hub passage <NUM>.

The hub passage <NUM> extends from the adjacent surface <NUM> in a proximal direction. The hub passage <NUM> is formed in a tapered shape whose inner diameter gradually increases toward the proximal direction. The hub passage <NUM> is preferably coaxial with the accommodation surface <NUM> and further coaxial with the lumen <NUM>. An inner diameter of the distal end of the hub passage <NUM> is preferably substantially equal to an inner diameter of the shaft <NUM>, and is not limited thereto. A part of the tapered hub passage <NUM> may include a Luer tapered portion <NUM> connectable to a syringe (not illustrated). A guide wire or a treatment catheter inserted from the hub proximal end opening <NUM> smoothly passes through the hub lumen <NUM> and the lumen <NUM> and protrudes from a distal end of the catheter <NUM>. Accordingly, the guide wire and the treatment catheter <NUM> can easily reach a target position such as a lesion area.

The wings <NUM> are formed so as to protrude from two opposing locations on an outer peripheral surface of the hub main body <NUM> such that an operator can easily grip and operate the hub <NUM>. The threading projection <NUM> is formed on the outer peripheral surface of the hub main body <NUM> on the proximal side. The threading projection <NUM> can be engaged with a lock type syringe or the like. The annular projection <NUM> is a projection formed over <NUM>° on an outer peripheral surface of the accommodation unit <NUM>. The annular projection <NUM> is fittable into a groove formed in an inner peripheral surface of the anti-kink protector <NUM>.

A constituent material of the hub <NUM> is not particularly limited as long as the material is a thermoplastic resin that can be injection-molded, a material that easily transmits heat or electromagnetic waves is preferable, and specific examples thereof include a polyolefin resin, a polyamide resin, a polycarbonate resin, and a polyester resin.

Next, a method of welding the shaft <NUM> and the hub <NUM> will be described. As illustrated in <FIG>, in the hub <NUM> before the shaft <NUM> is welded, an inner diameter of the accommodation surface <NUM> is larger on the distal side than on the proximal side. Specifically, an inner diameter D1 of the hub distal end opening <NUM> is larger than an inner diameter D2 of the distal end and the proximal end of the hub welded surface <NUM>. In addition, an inner diameter D3 of the distal end of the hub passage <NUM> is smaller than the inner diameter D2 of the proximal end of the hub welded surface <NUM>. The inner diameter D2 of the hub welded surface <NUM> is substantially equal to an outer diameter of the shaft proximal side outer surface <NUM>. The inner diameter D1 of the hub distal end opening <NUM> is, for example, <NUM>. The inner diameter D2 of the proximal end of the hub welded surface <NUM> is, for example, <NUM>. The inner diameter D3 of the distal end of the hub passage <NUM> is, for example, <NUM>.

First, the proximal side of the shaft <NUM> is inserted into the accommodation unit <NUM>, and the shaft proximal surface <NUM> is abutted against the adjacent surface <NUM>. It should be noted that the shaft proximal surface <NUM> may not be abutted against the adjacent surface <NUM> and there may be a gap between the shaft proximal surface <NUM> and the adjacent surface <NUM>. In addition, a proximal end of the shaft proximal side outer surface <NUM> is abutted against the proximal end of the hub welded surface <NUM>. It should be noted that the shaft proximal side outer surface <NUM> may not be abutted against the hub welded surface <NUM>, and there may be a gap between the shaft proximal side outer surface <NUM> and the hub welded surface <NUM>.

Next, a mandrel (not illustrated) is inserted into the lumen <NUM> of the shaft <NUM>, and the shaft proximal side outer surface <NUM> and the accommodation unit <NUM> of the hub <NUM> are heated. Accordingly, the shaft proximal side outer surface <NUM> and the accommodation surface <NUM> are melted, and the hub welded surface <NUM> and the shaft welded surface <NUM> are welded. The hub welded surface <NUM> and the shaft welded surface <NUM> may have an integrated structure by being mixed with each other. A heating method is not particularly limited, and examples thereof include a method of emitting electromagnetic waves having a wavelength that allows the electromagnetic waves to be transmitted through the hub <NUM> and does not allow the electromagnetic waves to be transmitted through the shaft outer surface <NUM>. Since the shaft outer surface <NUM> does not transmit the electromagnetic waves, the shaft proximal side outer surface <NUM> is heated and melted at first. Then heat of the shaft proximal side outer surface <NUM> is transferred to the accommodation unit <NUM> to melt the accommodation unit <NUM>.

The electromagnetic waves include infrared rays in addition to heat, microwaves, and visible light. The infrared rays are near-infrared rays having a wavelength of about <NUM> to <NUM>, mid-infrared rays having a wavelength of about <NUM> to <NUM>, or far-infrared rays having a wavelength of about <NUM> to <NUM>, and the infrared rays may be near-infrared rays, mid-infrared rays, far-infrared rays alone or containing two or more types thereof, and may also contain visible light or microwaves.

An electromagnetic wave irradiation method is not particularly limited, and a semiconductor solid-state laser such as a YAG laser using neodymium, a fiber laser, or the like may be used.

The term "electromagnetic waves are transmitted" means that, in addition to being transparent to the naked eye under visible light, a measured transmittance (hereinafter, referred to as the transmittance) is <NUM>% or more, and more preferably <NUM>% or more. The transmittance can be measured by irradiating a sheet having a thickness of <NUM> to <NUM> prepared by melt-pressing resin pellets with electromagnetic waves having a specific wavelength and using a spectroscopic analyzer, for example, a Fourier transform infrared and near-infrared spectroscopic analyzer. Therefore, since the electromagnetic waves are not limited to visible light, the term "electromagnetic waves are transmitted" includes being transparent with respect to a specific wavelength even if the electromagnetic waves are colored or opaque to the naked eye.

In addition, the term "electromagnetic waves are not transmitted" means that, in addition to being opaque or colored to the naked eye under visible light, the transmittance is less than <NUM>%, preferably less than <NUM>%, and more preferably less than <NUM>%. Therefore, since the electromagnetic waves are not limited to visible light, the term "electromagnetic waves are not transmitted" includes being opaque or absorbed with respect to a specific wavelength even if the electromagnetic waves are transparent to the naked eye.

In the outer layer <NUM>, a pigment that does not transmit or absorbs heat or electromagnetic waves may be mixed in an amount of <NUM> wt% or more and less than <NUM> wt%, preferably <NUM> wt% or more and <NUM> wt% or less, and more preferably <NUM> wt% or more and <NUM> wt% or less with respect to total resin. Alternatively, the outer layer <NUM> may not contain any pigment, contrast agent, or the like, and the resin forming the outer layer <NUM> may have a low transmittance with respect to a specific wavelength. Alternatively, in the outer layer <NUM>, a metal having X-ray contrast properties may be mixed in place of, or together with the pigment.

The pigment is not particularly limited as long as the pigment is a pigment that develops white, black, blue, red, or yellow or a mixture thereof, and a black pigment, for example, carbon black is preferable as a pigment that easily absorbs electromagnetic waves. The X-ray contrast agent is, for example, a compound of gold, bismuth, and tungsten, and is more preferably in the form of powder.

For example, as illustrated in (A) of <FIG>, when the shaft <NUM> and the hub <NUM> are welded to each other by irradiation with an infrared laser L, electromagnetic waves transmitted through the hub <NUM>, which is transparent to a wavelength of the irradiated infrared laser L, are absorbed by the opaque resin, pigment, or the like of the outer layer <NUM> of the shaft <NUM> and mainly generate heat. Accordingly, the resin of the outer layer <NUM> melts and transfers heat H to the accommodation unit <NUM> of the hub <NUM>, and at least a part of the accommodation surface <NUM> melts. As illustrated in (B) of <FIG>, a diameter of the melted accommodation surface <NUM> decreases, and the accommodation surface <NUM> is brought into close contact with the shaft proximal side outer surface <NUM>, and is welded to the shaft proximal side outer surface <NUM>. Accordingly, the hub welded surface <NUM> and the shaft welded surface <NUM> are welded and formed. At this time, the accommodation surface <NUM> melts and the diameter thereof decreases, and the outer peripheral surface of the accommodation unit <NUM> hardly melts and hardly deforms since heat is hardly transmitted. Therefore, due to the diameter decrease of the accommodation surface <NUM>, a material constituting the accommodation surface <NUM> flows so as to fill a gap between the accommodation surface <NUM> and the shaft proximal side outer surface <NUM>, and as a result, a length of the accommodation unit <NUM> along the axial center X is reduced. Accordingly, the accommodation unit <NUM> and the shaft proximal side outer surface <NUM> are favorably welded without any gap therebetween. In addition, the shaft proximal surface <NUM> and the adjacent surface <NUM> are also melted and welded by the heat generation of the outer layer <NUM>. It should be noted that the shaft proximal surface <NUM> may not be welded to the adjacent surface <NUM>.

When the shaft proximal side outer surface <NUM> and the accommodation surface <NUM> are welded, as illustrated in <FIG>, the shaft bubbles <NUM> are formed in the vicinity of the shaft welded surface <NUM> of the shaft <NUM>, and the hub bubbles <NUM> are formed in the vicinity of the hub welded surface <NUM> of the accommodation unit <NUM>. The bubbles are generated by evaporation of materials, mixing of air, or the like. By forming the shaft bubbles <NUM> and the hub bubbles <NUM>, the shaft welded surface <NUM> and the hub welded surface <NUM> have irregularities and are mixed with each other in a complicated manner, and are formed to enter each other. Therefore, the hub <NUM> and the shaft <NUM> are fixed to each other with a high coupling force. The hub welded surface <NUM> and the shaft welded surface <NUM> may have an integrated structure by being mixed with each other. It should be noted that only one of the shaft bubbles <NUM> and the hub bubbles <NUM> may be formed. In this case, the hub welded surface <NUM> and the shaft welded surface <NUM> are still mixed with each other in a complicated manner, and are still formed to enter each other. Therefore, the hub <NUM> and the shaft <NUM> are fixed to each other with a high coupling force.

The hub separated surface <NUM> located at the distal end of the hub welded surface <NUM> is not welded to the shaft separated surface <NUM>, and a gap is maintained between the hub separated surface <NUM> and the shaft separated surface <NUM>. When the entire hub welded surface <NUM> located on the proximal side of the hub separated surface <NUM> is welded to the shaft welded surface <NUM>, the irradiation of the infrared laser L is stopped. Accordingly, fixation of the hub <NUM> and the shaft <NUM> is completed.

As described above, the catheter <NUM> according to the present embodiment is the catheter <NUM> including: the shaft <NUM> that is the tubular body in which the lumen <NUM> extending the shaft <NUM> from the distal end to the proximal end is formed, and that includes the shaft proximal surface <NUM> in which the lumen <NUM> is opened and the shaft outer surface <NUM> that is the outer peripheral surface of the tubular body; and the hub <NUM> attached to the proximal end of the shaft <NUM>. The hub <NUM> includes the tubular accommodation unit <NUM> configured to accommodate the shaft <NUM>, the accommodation unit <NUM> includes the hub welded surface <NUM> directly welded to the shaft outer surface <NUM>, and at least one of the accommodation unit <NUM> and the hub <NUM> is formed with a plurality of bubbles at a position close to the hub welded surface <NUM>.

In the catheter <NUM> configured as described above, the accommodation unit <NUM> and the hub <NUM> are welded so as to enter each other by the plurality of bubbles. Therefore, the shaft <NUM> and the hub <NUM> can be firmly fixed. Therefore, the shaft <NUM> can be prevented from being detached from the hub <NUM> in a case where a high pressure of a contrast agent injected into the catheter <NUM> is applied, a case where a tensile force acts between the hub <NUM> and the shaft <NUM> when the shaft <NUM> is pulled out from a body, or the like.

In addition, the accommodation unit <NUM> is formed with the plurality of hub bubbles <NUM>, which are bubbles, at a position close to the hub welded surface <NUM>. Accordingly, the hub welded surface <NUM> of the accommodation unit <NUM> has a complicated shape with irregularities and is welded to the shaft outer surface <NUM>. Therefore, the shaft <NUM> and the hub <NUM> can be firmly fixed.

In addition, the shaft <NUM> is formed with the plurality of shaft bubbles <NUM>, which are bubbles, at a position close to the shaft welded surface <NUM> of the shaft outer surface <NUM> welded to the hub welded surface <NUM>. Accordingly, the shaft outer surface <NUM> has a complicated shape with irregularities and is welded to the hub welded surface <NUM>. Therefore, the shaft <NUM> and the hub <NUM> can be firmly fixed.

In addition, both the hub <NUM> and the shaft <NUM> include the plurality of bubbles, and the hub welded surface <NUM> and the shaft welded surface <NUM> of the shaft outer surface <NUM> welded to the hub welded surface <NUM> have irregularities and are welded so as to enter each other. Accordingly, the shaft <NUM> and the hub <NUM> can be fixed more firmly.

Claim 1:
A catheter (<NUM>) comprising:
a shaft (<NUM>) that is a tubular body in which a lumen (<NUM>) extending in the shaft (<NUM>) from a distal end to a proximal end is formed, and that includes a shaft proximal surface (<NUM>) in which the lumen (<NUM>) is opened and a shaft outer surface (<NUM>) that is an outer peripheral surface of the tubular body; and
a hub (<NUM>) attached to the proximal end of the shaft (<NUM>), wherein
the hub (<NUM>) includes a tubular accommodation unit (<NUM>) configured to accommodate the shaft (<NUM>),
the accommodation unit (<NUM>) includes a hub welded surface (<NUM>) directly welded to the shaft outer surface (<NUM>), characterized in that
at least one of the accommodation unit (<NUM>) and the hub (<NUM>) is formed with a plurality of bubbles at a position close to the hub welded surface (<NUM>).