JP7290153B2 - CATHETER AND CATHETER MANUFACTURING METHOD - Google Patents

Description

TECHNICAL FIELD The present invention relates to a catheter used in the medical field and a method for manufacturing the catheter, and more particularly to a catheter having a braided tube in which a soft resin tube is reinforced with a wire material such as metal.

BACKGROUND ART Conventionally, various catheters have been used in the medical field. For example, a catheter can be inserted into the body such as a blood vessel to inject a drug solution or collect blood or body fluid, and a device inserted into the body through such a catheter can be used for treatment or examination. Catheters are also used in medical devices such as dialysis machines to construct flow channels for blood and drug solutions outside the body.

A soft resin tube is generally used as such a catheter, and can be inserted into the body along a curved blood vessel or the like. In addition, since it is preferable to have sufficient pushability when inserting into a blood vessel, for example, as described in Japanese Patent Application Laid-Open No. 6-134034 (Patent Document 1), a blade made of metal or the like is inserted into the cylinder wall. Composite braided tubing embedded in the tissue has been proposed and utilized as a catheter.

By the way, as such a braid, a braided wire (braided sleeve) in which a wire having relatively high rigidity such as metal is braided is generally used. Therefore, when a long braided tube is cut to an appropriate length and commercialized, the braided wire exposed at the end face of the braided tube may protrude in the axial direction when the tube is bent or the like. Therefore, in the conventional braided tube, it has been proposed to cover the braided wire protruding from the end face of the braided tube by externally attaching a braided resin tube to the end of the braided tube and extending it in the axial direction. .

JP-A-6-134034

However, it is difficult to use a thick resin tube because the diameter of the resin tube is substantially increased by inserting it into the braided tube. there were. In addition, even if such a resin tube is extrapolated, the braided wire protruding from the end face of the braided tube is exposed inside the resin tube, so the exposed braided wire interferes with or deforms the filter or the like passing through the braided tube. It was difficult to obtain sufficient reliability.

Here, the problem to be solved by the present invention is to provide a catheter with a novel structure and a novel method for manufacturing a catheter, which can suppress the protrusion of the braided wire constituting the braid from the braided tube end surface. be.

First, the present inventors arranged the end tubes in series against the axial end face of the braided tube to prevent the braided wire (reinforcing braid) from protruding from the end face of the braided tube from being covered by the end tube. I considered. However, in order to connect the butted portions of the braid tube and the end tube, for example, when trying to weld by inserting a covering tube straddling both tubes, it is difficult to control the temperature in the welding process and it is difficult to obtain stable quality. I found out.

As a result of further investigation of such new problems, it was found that the specific heat of the reinforcing blade made of metal or the like is much smaller than that of the tube material made of synthetic resin, while the thermal conductivity of the tube material is that of the reinforcing blade. It was found that the reason for this is that the tube material has a much lower melting point than that of the reinforcing blade. For this reason, when the connecting portion of the braided tube and the end tube that are butted against each other and covered with the covering tube is heated during the welding process, the reinforcing braid is formed particularly at the butted portion of the braided tube and the end tube where the reinforcing braid is exposed. There is a possibility that the temperature becomes too high, the braid tube is locally melted and deformed, or the reinforcing braid is exposed or protrudes from the melted braid tube. On the other hand, if the heating temperature during the welding process is lowered in order to avoid such damage to the braided tube, sufficient welding strength can be stably obtained at the connecting portion between the braided tube and the end tube covered with the covering tube. it gets harder.

In view of the new problems as described above, the first aspect of the present invention, which has been made based on new knowledge obtained by the present inventors, is a catheter provided with a braided tube having reinforcing braids arranged thereon, An end tube is arranged at at least one end of the braided tube with its axial end faces abutted against each other, and a covering tube is fitted over both the braided tube and the end tube to extend over the both tubes. While being welded to the outer peripheral surface, the degree of welding of the covering tube to the outer end portion of the end tube in the axial direction is greater than the degree of welding of the covering tube to the butted portion of the braid tube and the end tube. It is what is done.

According to the catheter constructed according to this mode, the degree of welding of the cover tube inserted over the connecting portion between the braided tube and the end tube is reduced at the abutting portion between the braided tube and the end tube. It is possible to reduce or avoid damage to the braid tube due to high temperature during welding of the reinforcing braid exposed on the end surface of the braid tube. On the other hand, the strength of the connection between the braided tube and the end tube can be ensured by welding the covering tube in a region axially out of the butted portion of the braided tube and the end tube. Therefore, it is possible to reduce or avoid damage to the braided tube during welding while securing the welding strength for connecting the braided tube and the end tube.

A second aspect of the present invention is the catheter according to the first aspect, wherein the axially outer ends of the end tube and the cover tube are at the same position in the axial direction.

According to the catheter constructed according to this aspect, the end tube and the covering tube can be welded to each other at the outermost ends in the axial direction. can be prevented.

A third aspect of the present invention is the catheter according to the first aspect, wherein the covering tube protrudes axially outward from the end tube.

According to the catheter constructed according to this aspect, it is also possible to form the end portion of the catheter only with the covering tube and to construct it more flexibly. In addition, the stepped flexibility in the axial direction of the catheter is achieved by extending from the portion where the covering tube extends over the braided tube, through the portion where it extends over the non-braided end tube, to the protruding portion of the covering tube. You can also have it.

A fourth aspect of the present invention is the catheter according to the first aspect, wherein the end tube protrudes axially outward from the covering tube.

According to the catheter constructed according to this aspect, not only is the catheter gradually flexible in the axial direction, but the end tube, which has a smaller diameter than the covering tube, protrudes axially outward to constitute the end of the catheter. Therefore, it is possible to improve the insertability of the catheter.

A fifth aspect of the present invention is the catheter according to any one of the first to fourth aspects, wherein the covering tube is thinner than the braided tube.

According to the catheter constructed according to this aspect, an excessive increase in the outer diameter of the catheter can be suppressed, and deterioration of the insertability of the catheter can be avoided.

A sixth aspect of the present invention is the catheter according to any one of the first to fifth aspects, wherein the reinforcing braid is made of metal.

According to the catheter constructed according to this aspect, since the reinforcing blade is made of metal, the surrounding resin is likely to melt when heated and welded, and the reinforcing blade is likely to be exposed. A protrusion suppressing effect can be effectively enjoyed.

A seventh aspect of the present invention is the catheter according to any one of the first to sixth aspects, wherein the inner diameter dimension of the braided tube and the inner diameter dimension of the end tube at the butted portion of the braided tube and the end tube are made equal.

According to the catheter constructed according to this aspect, when another member such as a filter is delivered or collected through the inner hole of the catheter, the other member is moved to the abutting portion between the end tube and the braided tube on the inner surface of the catheter. The risk of getting caught can be reduced.

Although the catheter according to the present invention is not limited in any way, for example, it is preferably a filter recovery catheter that is placed in a blood vessel and recovers a filter that captures debris such as thrombi and blood clots. . That is, an eighth aspect of the present invention is a catheter according to any one of the first to seventh aspects, which is a filter recovery catheter for recovering a filter placed in a blood vessel.

A ninth aspect of the present invention is a method for manufacturing a catheter having a braided tube having reinforcing braids arranged thereon, wherein an end tube is arranged on at least one end side of the braided tube so that the axial end faces are separated from each other. are butted against each other, a covering tube is inserted over both the braided tube and the end tube, and then the extrapolated portion of the covering tube in the braided tube and the end tube is heated and welded (2) the amount of heat applied to the outer end portion of the end tube in the axial direction of the cover tube is greater than the amount of heat applied to the abutting portion of the braid tube and the end tube of the cover tube;

According to the method for manufacturing a catheter according to this aspect, the amount of heat applied to the abutting portion of the braided tube and the end tube in the covering tube is relatively small, so that the resin melts at the end of the braided tube and the reinforcing braid protrudes. In addition, by increasing the amount of heat applied to the outer end portion of the end tube in the axial direction of the covering tube, the covering tube and the end tube are more reliably welded, preventing the end tube from falling off. can be effectively prevented.

According to a tenth aspect of the present invention, in the method for manufacturing a catheter according to the ninth aspect, when heating and welding the outer portions of the covering tube of the braid tube and the end tube, The amount of heat applied to the inner part of the braided tube in the axial direction from the abutting part with the end tube is made larger than the amount of heat applied to the abutting part of the covering tube between the braided tube and the end tube.

According to the method for manufacturing a catheter according to this aspect, the amount of heat applied by welding is greater on both sides in the axial direction sandwiching the abutted portion than at the abutted portion between the braided tube and the end tube. , it is possible to obtain greater welding strength on both sides in the axial direction sandwiching the abutted portion between the braid tube and the end tube than at the abutted portion.

An eleventh aspect of the present invention is a catheter provided with a braided tube having reinforcing braids, wherein a covering tube is fitted over the braided tube, and the covering tube protrudes from an axial end of the braided tube. In addition, the projecting portion of the covering tube from the axial end of the braided tube overlaps the end face of the braided tube when viewed in the axial direction.

According to the catheter constructed according to this aspect, since the covering tube inserted over the braided tube overlaps the axial end face of the braided tube when viewed in the axial direction, the braided wire can be seen from the axial end face of the braided tube. Even if the braided wire protrudes, the tip of the protruding braided wire is axially covered by the covering tube or protrudes into the covering tube. In addition, since the covering tube covers the axial end face of the braided tube, the protruding braided wire is reduced to the necessary thickness in the axial direction while avoiding a significant increase in the diameter of the braided tube due to the thickening in the radial direction. It is also possible to secure and cover.

A twelfth aspect of the present invention is the catheter according to the eleventh aspect, wherein the inner peripheral surface of the protruding portion of the covering tube is located on the inner peripheral side of the reinforcing braid arranged on the braid tube. It is what we are doing.

According to the catheter constructed according to this aspect, the protrusion of the braided wire can be more reliably prevented. In this aspect, it is more preferable to employ an aspect in which the inner peripheral surface of the projecting portion of the covering tube is located on the inner peripheral side of all the reinforcing braids (braided wires) arranged on the braided tube.

A thirteenth aspect of the present invention is the catheter according to the eleventh or twelfth aspect, wherein the outer diameter of the protruding distal end portion of the covering tube is equal to or smaller than the outer diameter of the braided tube.

According to the catheter constructed according to this aspect, the outer diameter of the protruding tip of the covering tube is equal to or smaller than the outer diameter of the braided tube, so that the catheter can be smoothly inserted into a blood vessel or the like. be possible.

A fourteenth aspect of the present invention is the catheter according to any one of the eleventh to thirteenth aspects, wherein the projecting portion of the covering tube has a tapered shape in which the outer diameter gradually decreases toward the projecting tip. It has a part.

According to the catheter constructed according to this mode, catching or the like is suppressed when the catheter is inserted into the blood vessel, so that the workability of the procedure can be improved.

A fifteenth aspect of the present invention is the catheter according to any one of the eleventh to fourteenth aspects, wherein the protruding portion of the covering tube has a thickness dimension larger than that of the portion inserted onto the braided tube. It is enlarged.

According to the catheter constructed according to this aspect, the thickness dimension of the portion of the covering tube that is inserted over the braided tube is reduced, so that the outer diameter dimension of the catheter can be reduced and the insertability can be improved. In addition, by increasing the thickness of the portion protruding from the braid tube, the protrusion of the reinforcing braid from the braid tube can be prevented more stably.

Although the catheter according to the present invention is not particularly limited, it is preferably a delivery catheter, for example. That is, the sixteenth aspect of the present invention is the catheter according to any one of the eleventh to fifteenth aspects, wherein a filter capable of capturing debris such as thrombus in the blood is delivered to a predetermined position in the blood vessel. It is considered to be a delivery catheter that

In this aspect, it is also possible to position the filter with respect to the delivery catheter by bringing the projecting portion of the covering tube into contact with a stopper provided on the filter, as in an embodiment described later. In particular, for example, in combination with the thirteenth aspect or the fourteenth aspect, the outer diameter dimension at the projecting tip of the covering tube is set to be equal to or smaller than the outer diameter dimension of the blade tube, and the inner diameter dimension is also reduced toward the projecting tip. Alternatively, in combination with the fifteenth aspect, for example, by increasing the thickness dimension of the projecting portion of the covering tube toward the inner peripheral side, it is possible to reduce the diameter of the stopper provided on the filter, This also makes it possible to improve the insertability of the catheter when delivering the filter.

A seventeenth aspect of the present invention is the catheter according to any one of the eleventh to sixteenth aspects, wherein the projecting portion of the covering tube overlaps the axial end face of the braided tube in a state of contact. It is.

According to the catheter constructed according to this aspect, the tip of the braided wire protruding from the braided tube directly enters the covering tube, and the protruding braided wire can be prevented from being exposed in the covering tube. In addition, it is possible to prevent blood from entering and remaining in the gap between the braided tube and the covering tube in the axial direction.

An eighteenth aspect of the present invention is the catheter according to any one of the eleventh to seventeenth aspects, wherein a contrast marker is provided on the outer peripheral surface of the tip portion of the braided tube, and the contrast marker is placed on the cap. It is covered with a tube.

According to the catheter constructed according to this aspect, the catheter can be inserted into the blood vessel while confirming the position of the distal end portion of the braided tube during surgery. In particular, the axial distance from the distal end of the braid tube to the distal end of the catheter can be reduced by constructing the axial end of the catheter with a covering tube without providing a soft resin tube at the axial end of the braided tube. It is also possible to keep it small, and it is also possible to keep small the deviation between the position of the tip portion of the braided tube that can be confirmed during surgery and the actual position of the tip of the catheter.

According to the catheter and the method for manufacturing the catheter according to any one of the first to tenth aspects of the present invention, the braided tube is welded to the covering tube while ensuring the bonding strength of the end tube to the end of the braided tube. damage can be avoided.

Further, according to the catheter constructed according to any one of the eleventh to eighteenth aspects of the present invention, the braided wire (reinforcement braid) protruding axially from the braided tube is arranged axially with respect to the braided tube. Axial coverage is provided by a visually superimposed capping tube.

BRIEF DESCRIPTION OF THE DRAWINGS The front view which shows the whole catheter as the 1st Embodiment of this invention. FIG. 2 is a front view showing an enlarged main part of the catheter shown in FIG. 1; III-III sectional view in FIG. IV-IV sectional view in FIG. FIG. 5 is a vertical cross-sectional view showing the main part in the VV cross section of FIG. 4; FIG. 2 is an explanatory diagram for explaining a method of manufacturing the catheter shown in FIG. 1; FIG. 6 is a longitudinal sectional view showing a catheter as a second embodiment of the present invention, corresponding to FIG. 5; Fig. 6 is a vertical cross-sectional view showing a catheter as a third embodiment of the present invention, corresponding to Fig. 5; FIG. 4 is a front view showing the entirety of an embolus removal catheter including a delivery catheter, which is a fourth embodiment of the catheter of the present invention; FIG. 4 is a front view showing the entirety of a delivery catheter, which is a fourth embodiment of a catheter according to the present invention; FIG. 11 is a front view showing an enlarged main part of FIG. 10; FIG. 11 is an enlarged view of the XII-XII section of FIG. 11; FIG. 11 is an enlarged view of the XIII-XIII section of FIG. 11; FIG. 14 is a cross-sectional view showing a main part along the XIV-XIV cross section of FIG. 13; Explanatory drawing for demonstrating one example of the concrete manufacturing method of a split tube (covering tube). FIG. 10 is a front view showing the entirety of the wire with a filter that constitutes the embolus removal catheter shown in FIG. 9; FIG. 15 is a longitudinal cross-sectional view of another embodiment of the catheter of the present invention, corresponding to FIG. 14;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, FIGS. 1 to 5 show a filter retrieval catheter (hereinafter referred to as retrieval catheter) 10, which is a first embodiment of a catheter according to the present invention. This retrieval catheter 10 is a catheter for retrieving a filter that captures and removes debris such as thrombi and clots in the blood delivered to the treatment site in the blood vessel by a separate delivery catheter or the like from the blood vessel after treatment. be. In the following description, the axial direction refers to the lateral direction in FIG. 1 in which the recovery catheter 10 extends, the distal side refers to the left side in FIG. 1, and the proximal side refers to the right side in FIG. do.

More specifically, the retrieval catheter 10 includes a distal shaft 12 on the distal side and a proximal shaft 14 on the proximal side. The distal shaft 12 is made of a single-layer resin tube or the like, while the proximal shaft 14 is a hollow elongated member made of metal such as stainless steel or synthetic resin.

The distal shaft 12 is fixed to the outer peripheral surface of the distal end portion of the distal shaft 14 , and the long proximal shaft 14 extends from the distal end side of the distal shaft 12 . The inner diameter of the distal shaft 12 is larger than the outer diameter of the proximal shaft 14, and the proximal end of the distal shaft 12 is a port opened to the outside at the intermediate portion in the longitudinal direction of the recovery catheter 10. Section 16. Also, the proximal end of the proximal shaft 14 is provided with a connector portion 18 that can be gripped and operated by the user.

On the other hand, the distal end portion of the distal shaft 12 is fitted with an outer tube 20 made of a braided tube. In this embodiment, the braided tube targeted by the present invention is the outer tube 20, and as described in detail below, the catheter targeted by the present invention is the outer tube 20, which will be described later according to the present invention. It has a composite structure in which an end tube 28 and a cover tube 30 are provided. Therefore, the present invention can be interpreted without including the distal shaft 12 and the proximal shaft 14 as targets.

That is, the outer tube 20 is configured by embedding and fixing a reinforcing braid 22 made of metal or the like in a cylindrical wall 24 made of a resin tube. It is made up of braided tubes over its entire length. In this embodiment, the reinforcing blade 22 is embedded in the middle portion of the cylindrical wall 24 in the thickness direction, and the inner peripheral side and the outer peripheral side of the reinforcing blade 22 are each covered with a resin tube material. Although the structures of the distal shaft 12 and the proximal shaft 14 are not limited in any way, these shafts 12 and 14 are blades in which reinforcing blades are embedded and fixed inside the cylinder wall like the outer tube 20. By using a tube, the recovery catheter 10 can be made of a braided tube over substantially the entire length in the axial direction.

In this embodiment, the radial width dimension To (see FIG. 4) of the outer tube 20 is preferably 0.04 mm≦To≦1.0 mm, and the axial dimension L (see FIG. 3) is preferably is 50 mm≦L≦70 mm. By setting the radial thickness dimension To and the axial dimension L within the above ranges, flexibility and good operability can be obtained. Further, a ring-shaped contrast marker 26 made of Pt or the like is externally attached to the outer peripheral surface of the distal end portion of the outer tube 20 . As a result, the insertion operation of the recovery catheter 10 can be performed while confirming the position of the distal end portion of the outer tube 20 with X-rays. Of course, in this embodiment, the reinforcing blade 22 made of metal or the like extends almost to the tip of the outer tube 20, and the reinforcing blade 22 can also confirm the position of the tip portion of the outer tube 20 with X-rays. Therefore, the contrast marker 26 is not essential.

The outer tube 20, which is a braided tube, has a three-layer structure. The innermost layer is made of synthetic resin such as PTFE (polytetrafluoroethylene). A reinforcing braid 22 consisting of a mesh-like sleeve made of braided wires made of synthetic resin is provided. Furthermore, an outer layer of a synthetic resin made of polyamide or the like is formed on the outer peripheral side of the reinforcing blade 22, and the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer are bonded or welded to form a reinforcing blade. The inner and outer layers are integrated by fixing in a state in which 22 is embedded. That is, the cylindrical wall 24 in which the reinforcing braid 22 is embedded is formed by including the inner layer made of PTFE or the like and the outer layer made of polyamide or the like. In this embodiment, the outer layer of the cylindrical wall 24 of the outer tube 20, the end tubes 28 (28a, 28b) described later, and the cover tube 30 are made of substantially the same synthetic resin, that is, under conditions similar to each other. These tubes 20, 28 and 30 are made of nylon, particularly in this embodiment. It should be noted that polyamide elastomer, urethane, or the like, for example, can be suitably used as the material forming each of the tubes 20, 28, and 30. FIG. Further, stainless steel, tungsten, or the like, for example, can be suitably used as the material that constitutes the reinforcing blade 22 .

At least one end of the outer tube 20 is provided with an end tube 28 that faces the outer tube 20, and in this embodiment, a gap is provided between the end tube 28 and the outer tube 20. They are arranged in series with the end surfaces substantially in contact with each other. In particular, in the present embodiment, end tubes 28a and 28b are provided on both sides of the outer tube 20, and the distal end tube 28a is provided on the distal side of the outer tube 20, while the proximal side of the outer tube 20 is provided. is provided with a proximal end tube 28b. The reinforcing braid 22 is not embedded in these end tubes 28a, 28b, and both end tubes 28a, 28b are made softer than the outer tube 20. As shown in FIG. Although the outer tube 20 is relatively hard because the reinforcing blade 22 is embedded therein, the rigidity of the resin portion of the outer tube 20, that is, the cylindrical wall 24 is not limited in any way. For example, it may be made softer than both end tubes 28a and 28b. Further, in the present embodiment, the outer diameter dimension and inner diameter dimension of the end tubes 28a and 28b are substantially equal to those of the outer tube 20. As shown in FIG. By making the outer and inner diameters of the end tubes 28a, 28b and the outer tube 20 substantially equal, the outer and inner peripheral surfaces of the end tubes 28a, 28b and the outer tube 20 can be It is possible to make it difficult to create a step.

The distal end portion of the distal shaft 12 is inserted into the outer tube 20 as described above from the proximal side of the proximal end tube 28b provided on the proximal side thereof. The side inner peripheral surface is welded or adhered to the outer peripheral surface of the distal shaft 12, and the diameter of the proximal end portion of the proximal end tube 28b is reduced. The proximal portion of the proximal end tube 28b may not be reduced in diameter, and the outer diameter dimension of the proximal end tube 28b may be substantially constant in the axial direction.

Furthermore, a covering tube 30 is externally inserted on the outer peripheral side of the outer tube 20 so as to cover the outer peripheral surface of the outer tube 20 over the entire length in the axial direction. The covering tube 30 is thinner than the outer tube 20 and preferably has a radial width dimension Tc (see FIG. 4) of 0.01 mm≦Tc≦0.10 mm. The base end side of the covering tube 30 is externally inserted across the abutting portion with the base end tube 28b provided on the base end side of the outer tube 20. From the base end of the covering tube 30, A proximal end tube 28b protrudes axially outward (to the proximal side). The proximal end tube 28b does not have to protrude from the proximal end of the covering tube 30, and the proximal end of the proximal end tube 28b and the proximal end of the covering tube 30 are substantially at the same position in the axial direction. good too.

On the other hand, the tip side of the covering tube 30 protrudes further to the tip side than the outer tube 20 and covers substantially the entire length of the tip end tube 28a provided on the tip side of the outer tube 20. In this embodiment, The tip side end face of the covering tube 30 and the tip side end face of the tip side end tube 28a are at substantially the same position in the axial direction. Over substantially the entire length of the covering tube 30, the covering tube 30 is fixed to the outer peripheral surfaces of the outer tube 20 and both end tubes 28a and 28b. That is, in this embodiment, the distal end face of the recovery catheter 10 is composed of the distal end face of the distal end tube 28a and the distal end face of the covering tube 30, and is flat and extends perpendicularly to the axial direction. It is considered to be an annular surface. In this embodiment, the covering tube 30 is arranged so as to cover the outer periphery of the contrast marker 26 .

In this embodiment, the covering tube 30 is divided into four pieces in the length direction in a single-piece state before being inserted onto the outer tube 20, and is composed of divided tubes 32a, 32b, 32c, and 32d. In other words, the split tubes 32a, 32b, 32c, and 32d arranged in series in the longitudinal direction from the distal end side are externally inserted over the outer tube 20 and the both end tubes 28a and 28b, and are positioned at the most distal end side. The split tube 32a protrudes from the outer tube 20 to the distal side and covers the distal end tube 28a, while the split tube 32d positioned most proximally protrudes from the outer tube 20 to the proximal side to form the proximal end tube. 28b. The number of split tubes forming the covering tube 30 is not limited at all. That is, the number may be two, three, or five or more, and can be changed as appropriate. Of course, the covering tube need not consist of split tubes, but may consist of one tubular member.

These split tubes 32a, 32b, 32c, 32d, outer tube 20, and both-end tubes 28a, 28b are heat-treated to melt and integrate them to form the covering tube 30, The covering tube 30 is welded to the outer peripheral surfaces of the outer tube 20 and both end tubes 28a and 28b. That is, the split tube 32a at the distal end is welded to the outer peripheral surfaces of both the outer tube 20 and the distal end tube 28a, and the split tube 32d at the proximal end is welded to the outer tube 20 and the proximal end tube 28a. It is welded to both tubes 20, 28b across the side end tube 28b. On the other hand, the intermediate split tubes 32b and 32c are welded to the outer peripheral surface of the outer tube 20. As shown in FIG.

A specific example of the manufacturing method of the recovery catheter 10 will be described below with reference to FIGS. 6(a) to 6(c), but the manufacturing method of the recovery catheter 10 is not limited in any way. 6A to 6C, illustration of the contrast marker (26) is omitted.

That is, as shown in FIG. 6(a), the outer tube 20 and both end tubes 28a and 28b are fitted over a core rod 34 extending substantially straight with their axial end surfaces facing each other, and further A covering tube 30 is fitted over the outer peripheral surfaces of the tubes 20, 28a, 28b. After that, the core rod 34 with the tubes 20 , 28 a , 28 b , 30 inserted is set in a substantially cylindrical welding die 36 . The welding die 36 and the core rod 34 are arranged on the same central axis, and an appropriate gap is set between the outer peripheral surface of the covering tube 30 and the inner peripheral surface of the welding die 36 . Then, the welding mold 36 is heated to heat and melt the cover tube 30, thereby welding the externally inserted portion of the cover tube 30 to the outer tube 20 and both end tubes 28a and 28b. The end tube constructed according to any one of the first to tenth aspects is the distal end tube 28a, and in FIGS. and covering tube 30 are welded together, but the manner in which the proximal end tube 28b and covering tube 30 (divided tube 32d) are fixed is not limited in any way. Similarly, it may be structured according to any one of the first to tenth aspects, and may be fixed to each other by means other than welding, such as adhesion. Also, such welding may be performed in a state in which a thin-walled shrink tube is further fitted onto the covering tube 30 . In such a case, the temperature of the welding mold 36 and the temperature applied to the covering tube 30 do not necessarily match, but since there is a correlation, the higher the temperature of the welding mold 36, the higher the covering temperature. The temperature applied to tube 30) is also believed to be high.

Here, FIG. 6(a) shows how the cover tube 30 is welded to a portion of the outer tube 20 closer to the proximal end than the butted portion of the outer tube 20 and the distal end tube 28a. That is, in FIG. 6A, the welding die 36 is positioned on the proximal side of the abutted portion between the outer tube 20 and the distal end tube 28a, and welding is performed in this state, whereby the covering tube 30 and the outer tube 20 are welded to each other. Although the welding conditions in such a state are not limited in any way, in this embodiment, the welding mold 36 is heated to an appropriately set temperature within the range of 165°C to 235°C. Heat welding is preferably performed for an appropriately set time between 15 seconds. More preferably, the heat treatment is performed at a temperature within the range of 180 to 220 degrees for 8 to 12 seconds.

After the welding, the welding die 36 and the core rod 34 are moved relative to each other as shown in FIG. Let Welding is performed in this state to weld the covering tube 30, the outer tube 20 and the tip end tube 28a to each other. Although the welding conditions in such a state are not limited in any way, in the present embodiment, in FIG. It is preferable to heat and weld for an appropriately set time between 5 and 30 seconds in a heated state. More preferably, the heat treatment is performed for 8 to 12 seconds at a temperature within the range of 150 to 165 degrees and lower than those shown in FIGS. 6(a) and 6(c).

Further, after welding, the welding die 36 and the core rod 34 are moved relative to each other as shown in FIG. be positioned at Welding is performed in this state to weld the covering tube 30 and the axially outer end portion of the distal end tube 28a to each other. Although the welding conditions in such a state are not limited in any way, in this embodiment, the welding mold 36 is heated to an appropriately set temperature within the range of 160° C. to 220° C. Heat welding is preferably performed for an appropriately set time between 15 seconds. More preferably, the heat treatment is performed at a temperature within the range of 165 to 200 degrees for 5 to 10 seconds.

Thereafter, the separately prepared distal shaft 12, proximal shaft 14, and connector portion 18 are fixed to the outer tube 20 manufactured by the procedure shown in FIGS. to manufacture. Note that the fixing means and the order of fixing are not limited in any way.

Here, although it depends on the material of each tube, in this embodiment, the outer layer of the outer tube 20, the tip end tube 28a, and the covering tube 30 are made of substantially the same material. (The amount of heat energy) can be represented by (heating temperature)×(heating time). That is, in the present embodiment, the amount of heat applied during welding is (a portion of the outer tube 20 axially inward of the abutting portion with the distal end tube 28a)≧(a portion of the distal end tube 28a in the axial direction) outer end portion)>(butting portion between outer tube 20 and tip end tube 28a). Since the outer tube 20 has the metal reinforcing braid 22 embedded in it as compared to the distal end tube 28a, it is preferable to direction inward portion)>(axial outward end portion of distal end tube 28a). Therefore, in terms of the degree of welding with the cover tube 30 as well, (a portion of the outer tube 20 axially inward of the abutting portion with the distal end tube 28a)>(axially outward of the distal end tube 28a) end portion)>(butting portion of outer tube 20 and distal end tube 28a), and covering tube 30 sandwiches the butting portion rather than the butting portion of outer tube 20 and distal end tube 28a. However, the degree of welding is increased on both sides.

In the above-described specific examples, in FIGS. 6(a) to (c), the welding molds 36 are set at positions where they do not overlap in the axial direction. The weld locations may partially overlap axially. When the welding die 36 is sequentially moved in the axial direction to weld each part, the movement position of the welding die 36 is adjusted so that the welding process is performed at partially overlapped positions. By applying the welding process at continuous positions without overlapping, or by performing the welding process at discontinuous positions separated by a predetermined distance, in addition to or instead of the heating temperature of the welding mold 36, each tube It becomes possible to control the amount of welding heat applied to 20, 28a, 28b, 30 for each portion. When performing heat treatment on the same location a plurality of times by partially overlapping the positions of the welding molds 36 in the axial direction, for example, the effective heating temperature and heating time for the location, that is, the resin The heat quantity of the heat treatment can be evaluated by the heating time at the melting temperature or higher.

In addition, even if the entire welding mold 36 is heated substantially uniformly, the temperature at both ends in the axial direction tends to be lower than that at the intermediate portion due to unevenness in the heat radiation area. By utilizing such temperature characteristics of the welding mold 36 or by locally cooling the welding mold 36 with air or the like, for example, welding of the butted portion between the outer tube 20 and the distal end tube 28a can be performed. , can also be performed at lower temperatures.

By the welding process as described above, the boundary between the overlapping surfaces of the covering tube 30, the outer tube 20, and the tip end tube 28a disappears to form an integral resin structure. Of course, it suffices if the required welding strength is realized, and between the overlapping surfaces of these tubes, particularly between the overlapping surfaces of the covering tube 30 at the butted portion of the outer tube 20 and the tip end tube 28a, A space between butt faces of the outer tube 20 and the distal end tube 28a may remain to the extent that the boundary can be confirmed.

In this embodiment, since the outer layer of the outer tube 20, the tip end tube 28a, and the cover tube 30 are made of substantially the same material, there is a correlation between the amount of heat applied during welding and the degree of welding. If different materials are used for the tube, such as a material that is easy to weld or a material that is difficult to weld, there may be no correlation between the amount of heat applied during welding and the degree of welding. However, the degree of welding in the covering tube 30 is made greater at the axially outer end portion of the distal end tube 28a than at the abutted portion between the outer tube 20 and the distal end tube 28a, which will be described later. The effects of the present invention are exhibited. In the manufactured catheter, the degree of welding of the covering tube can be interpreted as the degree of integration by melting. It can be objectively grasped as (the force required for welding) ≈ (the degree of welding).

Also, the recovery catheter 10 is used, for example, for recovering a filter that is delivered to a predetermined position in a blood vessel by a separate delivery catheter and traps debris such as thrombi and blood clots in the blood. That is, the filter placed in the blood vessel and used for treatment is housed inside the outer tube 20, and the filter is recovered by removing the recovery catheter 10 in this state. In the present embodiment, since the inner diameter of the distal end tube 28a and the inner diameter of the outer tube 20 are substantially equal, the filter does not get caught on the inner surface of the recovery catheter 10, and the filter is attached to the outer tube 20. Can be accommodated inside. The structure of the filter, the method of accommodating the filter inside the outer tube 20, and the like are not limited in any way.

In the recovery catheter 10 of the present embodiment constructed as described above, the degree of welding is varied by varying the amount of heat applied during welding in the axial direction of the covering tube 30 . That is, the amount of heat applied to the axially outer end portion of the distal end tube 28a of the covering tube 30 is greater than the amount of heat applied to the butted portion of the outer tube 20 and the distal end tube 28a of the covering tube 30. As a result, the welding degree of the outer end portion of the tip end tube 28a in the covering tube 30 in the axial direction is greater than the welding degree of the butted portion of the outer tube 20 and the tip end tube 28a of the covering tube 30. are doing.

As a result, the amount of heat applied to the abutting portion of the outer tube 20 and the distal end tube 28a, that is, the heating temperature, for example, can be kept low, thereby melting the resin at the end of the outer tube 20 and reinforcing it. Projection of the blade 22 can be avoided. In addition, since the cover tube 30 and the distal end tube 28a are firmly welded to each other on the distal end side of the outer tube 20, the distal end tube 28a can be stably positioned on the distal end side of the outer tube 20. As a result, the axial protrusion of the reinforcing blade 22 can be more reliably prevented.

In particular, in the present embodiment, compared to the degree of welding of the covering tube 30 at the abutting portion of the outer tube 20 and the distal end tube 28a, the outer tube 20 is axially inner than the abutting portion of the outer tube 20 and the distal end tube 28a. Since the degree of welding of the covering tube 30 in the portion on the one side is greater, the degree of welding is greater on both sides of the butted portion compared to the portion where the outer tube 20 and the tip end tube 28a are abutted. It is That is, since the outer tube 20 and the distal end tube 28a are firmly fixed via the covering tube 30 without increasing the welding degree between the butted end surfaces, the distal end tube 28a from the outer tube 20 is falling off can be effectively prevented.

In addition, in the present embodiment, since the distal end face of the covering tube 30 and the distal end face of the distal end tube 28a are located at the same position in the axial direction, both tubes 28a and 30 can be welded from their distal ends. It is possible to effectively prevent the cover tube 30 and the distal end tube 28a from being peeled off.

Furthermore, in the present embodiment, since the covering tube 30 is thin, even if it is inserted over the outer tube 20, the diameter of the recovery catheter 10 is not increased, and the insertion of the recovery catheter 10 is improved. deterioration can be prevented.

The material of the reinforcing blade 22 is preferably metal or synthetic resin, but is not limited in any way. However, since the material of the reinforcing blade 22 is made of metal, the temperature of the reinforcing blade 22 is lower than in the case where the reinforcing blade 22 is made of synthetic resin when the covering tube 30 is heated and welded. is likely to rise, and the surrounding resin (cylindrical wall 24) is likely to melt. Therefore, the effect of the present embodiment, which suppresses the heating temperature during welding and prevents the resin from melting, can be effectively enjoyed.

Next, FIG. 7 shows a filter recovery catheter (hereinafter referred to as recovery catheter) 40, which is a second embodiment of the catheter according to the present invention. In the recovery catheter 40 of the present embodiment, the covering tube 30 protrudes further in the axial direction than the end tube 28. located on the tip side. In the following description, members and parts that are substantially the same as those in the above embodiment are denoted by the same reference numerals as in the above embodiment, and detailed description thereof will be omitted.

Also in the present embodiment, when the covering tube 30 is welded, the degree of welding of the axially outer end portion of the distal end tube 28a compared to the abutting portion of the outer tube 20 and the distal end tube 28a is set, for example, By increasing the amount of heat to be applied, for example, the same effect as in the first embodiment can be exhibited.

In particular, in this embodiment, the distal end portion of the recovery catheter 40 is formed only by the covering tube 30, so that the distal end portion of the recovery catheter 40 can be configured flexibly. Since the proximal side of the recovery catheter 40 has a double layer structure of the covering tube 30 and the distal end tube 28a, the structure can be made more rigid. Since it has a double-layered structure of the cover tube 30 and the outer tube 20, it can be made even harder. In this way, by projecting the covering tube 30 further to the distal side than the distal end tube 28a, the flexibility of the recovery catheter 40 can be varied in the axial direction, for example, from the distal side to the proximal side. It can also be configured so that it becomes harder gradually.

Next, FIG. 8 shows a filter recovery catheter (hereinafter referred to as recovery catheter) 50, which is a third embodiment of the catheter according to the present invention. In the recovery catheter 50 of the present embodiment, the end tube 28 protrudes axially outward from the covering tube 30 . located on the tip side.

Also in the present embodiment, when the covering tube 30 is welded, the degree of welding of the axially outer end portion of the distal end tube 28a compared to the abutting portion of the outer tube 20 and the distal end tube 28a is set, for example, By increasing the amount of heat to be applied, for example, the same effect as in the first embodiment can be exhibited.

In particular, in the present embodiment, since the distal end tube 28a protrudes further to the distal side than the covering tube 30, the flexibility of the recovery catheter 50 varies in the axial direction, as in the second embodiment. For example, it can be configured so that it becomes harder from the distal side toward the proximal side. Further, since the distal end tube 28a has a smaller diameter than the covering tube 30, the distal end of the recovery catheter 50 can be made smaller in diameter, and the insertability of the recovery catheter 50 can be improved.

FIG. 9 shows an embolectomy catheter 62 comprising a delivery catheter 60, which is a fourth embodiment of a catheter according to the invention. 10-14 show such a delivery catheter 60 alone. This delivery catheter 60 is a catheter for delivering a filter that captures and removes debris such as thrombi and blood clots in blood to a predetermined position such as a treatment site in a blood vessel. In the following description, the axial direction refers to the lateral direction in FIG. 9 in which the delivery catheter 60 extends, the distal side refers to the left side in FIG. 9, and the proximal side refers to the right side in FIG. .

More specifically, the delivery catheter 60 includes a distal shaft 64 on the distal side and a proximal shaft 66 on the proximal side. The distal shaft 64 is made of a single-layer resin tube or the like, while the proximal shaft 66 is a hollow elongated member made of metal such as stainless steel or synthetic resin.

Also, the distal shaft 64 is fixed to the outer peripheral surface of the distal end portion of the distal shaft 66 , and the long proximal shaft 66 extends from the proximal end side of the distal shaft 64 . The inner diameter dimension of the distal shaft 64 is larger than the outer diameter dimension of the proximal shaft 66, and the proximal end side of the distal shaft 64 at the intermediate portion in the length direction of the delivery catheter 60 is a port portion opened to the outside. 68. Also, the proximal end of the proximal shaft 66 is provided with a connector portion 70 that can be gripped and operated by the user.

On the other hand, the distal end portion of the distal shaft 64 is fitted with an outer tube 72 made of a braided tube. In this embodiment, the braided tube targeted by the present invention is the outer tube 72, and as will be described in detail below, the catheter targeted by the present invention covers the outer tube 72 according to the present invention. It has a composite structure with a tube. Therefore, the present invention can be interpreted without including the distal shaft 64 and the proximal shaft 66 as targets.

That is, the outer tube 72 is constructed by embedding and fixing a reinforcing braid 74 made of metal or the like in a cylinder wall 76 made of a resin tube. It is composed of In this embodiment, the reinforcing blade 74 is embedded in the middle portion in the thickness direction of the tubular wall 76, and the inner peripheral side and the outer peripheral side of the reinforcing blade 74 are each covered with a resin tube material. Although the structures of the distal shaft 64 and the proximal shaft 66 are not limited in any way, these shafts 64 and 66 are blades in which reinforcing blades are embedded and fixed inside the cylinder wall, similar to the outer tube 72. By using a tube, it is possible to configure the delivery catheter 60 with a braided tube over substantially the entire length in the axial direction.

In this embodiment, the radial width dimension T (see FIG. 13) of the outer tube 72 is preferably 0.04 mm≦T≦1.0 mm, and the axial dimension L (see FIG. 11) is preferably is 50 mm≦L≦70 mm. By setting the radial thickness dimension T and the axial dimension L within the above ranges, flexibility and good operability can be obtained. Further, a ring-shaped contrast marker 78 made of Pt or the like is externally attached to the outer peripheral surface of the distal end portion of the outer tube 72 . As a result, the insertion operation of the delivery catheter 60 can be performed while confirming the position of the distal end portion of the outer tube 72 with X-rays. However, in the present embodiment, the reinforcing blade 74 made of metal or the like extends almost to the tip of the outer tube 72, and the position of the tip portion of the outer tube 72 can be confirmed by X-ray even with the reinforcing blade 74. , the contrast marker 78 is not essential.

The outer tube 72, which is a braided tube, has a three-layer structure. The innermost layer is made of synthetic resin such as PTFE (polytetrafluoroethylene). A reinforcing braid 74 consisting of a mesh-like sleeve made of braided wires made of synthetic resin is provided. Furthermore, an outer layer of a synthetic resin made of polyamide or the like is formed on the outer peripheral side of the reinforcing blade 74, and the outer peripheral surface of the inner layer and the inner peripheral surface of the outer layer are bonded or welded to form a reinforcing blade. The inner and outer layers are integrated by fixing with the 74 embedded. That is, a cylindrical wall 76 in which the reinforcing braid 74 is embedded is formed by including an inner layer made of PTFE or the like and an outer layer made of polyamide or the like.

An end tube 80 is arranged in series at the proximal end of the outer tube 72 so that the end faces of the outer tube 72 abut each other. In this embodiment, the reinforcing braid 74 is not embedded in the end tube 80 , and the end tube 80 is softer than the outer tube 72 . In particular, in this embodiment, the outer diameter and inner diameter of the end tube 80 are substantially equal to those of the outer tube 72 .

The distal end portion of the distal shaft 64 is inserted into the outer tube 72 as described above from the proximal side of the end tube 80 provided on the proximal side thereof, and the inner peripheral surface of the proximal side of the end tube 80 is distal. It is welded or adhered to the outer peripheral surface of the tar shaft 64, and in this embodiment, the proximal end portion of the end tube 80 is reduced in diameter. The proximal end portion of the end tube 80 may not be reduced in diameter, and the outer diameter dimension of the end tube 80 may be substantially constant in the axial direction.

Furthermore, a covering tube 82 is externally inserted on the outer peripheral side of the outer tube 72 so as to cover the outer peripheral surface of the outer tube 72 over the entire length in the axial direction. The base end side of the covering tube 82 is externally inserted across the abutting portion of the base end of the outer tube 72 with the end tube 80 , and the end tube 80 extends axially outward from the base end of the covering tube 82 ( proximal side). The end tube 80 may not protrude from the proximal end of the covering tube 82, and the proximal end of the end tube 80 and the proximal end of the covering tube 82 may be substantially at the same position in the axial direction. On the other hand, the distal end side of the covering tube 82 protrudes axially outward (toward the distal end side) from the distal end portion of the outer tube 72 . A covering tube 82 is fixed to the outer peripheral surfaces of the outer tube 72 and the end tube 80 by adhesion, welding, or the like. In addition, in this embodiment, the covering tube 82 is arranged so as to cover the outer periphery of the contrast marker 78 .

Here, the outer diameter of the portion of the covering tube 82 that protrudes from the outer tube 72 toward the distal end (a distal end cover portion 86 to be described later) is gradually reduced toward the projecting distal end, while the outer diameter of the portion that protrudes from the outer tube 72 toward the distal end is gradually decreased toward the distal end. The inner diameter of the portion (tip cover portion 86) that protrudes outward is substantially equal to the inner diameter of the outer tube 72, and is substantially constant in the axial direction including the protruding tip. As a result, the portion of the covering tube 82 that protrudes from the outer tube 72 toward the distal end is positioned axially outward (distal end) of the outer tube 72, and the covering tube 82 is located at the distal end of the outer tube 72 when viewed in the axial direction. It overlaps over substantially the entire side end surface. In the present embodiment, the inner peripheral surface 84 of the portion of the covering tube 82 that protrudes from the outer tube 72 toward the distal end (the distal end cover portion 86 ) is larger than all the reinforcing blades 74 embedded in the outer tube 72 . Located on the inner circumference side.

That is, the covering tube 82 includes a tip cover portion 86 projecting from the outer tube 72 to the tip side. Therefore, in the present embodiment, the portion of the cover tube 82 that protrudes from the axial end (tip) of the outer tube 72 (braided tube) is constituted by the tip cover portion 86 . The tip cover portion 86 has a predetermined radial width dimension W ₁ (see FIG. 14) and extends from the outer tube 72 to the tip side, and is a portion of the cover tube 82 that covers the outer peripheral surface of the outer tube 72. is smaller than the tip cover portion 86 ( _{W 2 <} W ₁ ).

In the present embodiment, the outer peripheral surface of the tip cover portion 86 has an inclined surface in which the outer diameter dimension gradually decreases toward the protruding tip. have. Particularly in this embodiment, the outer peripheral surface of the tapered portion 88 is a curved inclined surface 90 that is curved and inclined. Accordingly, in the present embodiment, the outer diameter of the covering tube 82 (the distal end cover portion 86 ) at the projecting distal end portion is smaller than the outer diameter of the outer tube 72 . Further, in the present embodiment, the proximal end surface of the distal end cover portion 86 and the distal end surface of the outer tube 72 overlap each other while being in contact with each other without a gap.

In this embodiment, the covering tube 82 is divided into four pieces in the length direction in a single piece state before being inserted onto the outer tube 72, and is composed of divided tubes 92a, 92b, 92c, and 92d. In other words, the split tubes 92a, 92b, 92c, and 92d arranged in series in the longitudinal direction from the distal end side are externally inserted over the outer tube 72 and the end tube 80, and the split tube located at the most distal end side. 92a has a distal end cover portion 86 and protrudes distally from the outer tube 72, while a split tube 92d positioned most proximally protrudes proximally from the outer tube 72 and straddles the end tube 80. are doing. The number of split tubes forming the covering tube 82 is not limited at all. That is, the number may be two, three, or five or more, and can be changed as appropriate. Of course, the covering tube need not consist of split tubes, but may consist of one tubular member.

These split tubes 92a, 92b, 92c and 92d, the outer tube 72 and the end tube 80 are heat-treated to melt and integrate them to form the covering tube 82 and the covering tube 82. A tube 82 is welded to the outer peripheral surfaces of the outer tube 72 and the end tube 80 . That is, the split tube 92a at the distal end is welded to the outer peripheral surface of the outer tube 72 and protrudes toward the distal end, while the split tube 92d at the proximal end straddles the outer tube 72 and the end tube 80 to extend both the tubes 72 and 80. is welded to On the other hand, intermediate split tubes 92 b and 92 c are welded to the outer peripheral surface of the outer tube 72 .

A specific example of the method for manufacturing the split tube 92a will be described below with reference to FIG. 15, but the method for manufacturing the split tube 92a and the covering tube 82 is not limited in any way.

That is, for example, after inserting a stepped pin 94 having a larger diameter on the proximal side into a resin tube 92a' having a substantially constant thickness, the proximal side (stepped pin) of the resin tube 92a' The portion inserted over the large diameter portion of the pin 94 ) is stretched by the stretching plate 96 . As a result, a sufficient axial dimension is ensured while the proximal side of the resin tube 92a' is thinner than the distal side. After removing the extension plate 96 and the stepped pin 94 from this state, the resin tube 92a' is cut at a predetermined position on the distal end side so that the distal end side has a smaller diameter than the proximal end side before being externally inserted into the outer tube 72. A split tube 92a is formed.

Then, the split tubes 92d, 92c, and 92b are sequentially inserted onto the outer tube 72 and the end tube 80 from the distal end side, and finally the split tube 92a formed as described above is attached to the tip portion of the small diameter. protrudes axially outward from the outer tube 72 . Further, a core rod (not shown) extending substantially straight is inserted into the outer tube 72 and the split tube 92a in such a state, and heat welding is performed to form the split tube 92a (covering tube 82) as shown in FIG. It is affixed in a state where it is That is, in the present embodiment, the split tube 92a is externally inserted into the distal end portion of the outer tube 72 and is welded, so that the proximal end surface of the distal end cover portion 86 and the distal end surface of the outer tube 72 are brought together. They are in contact with each other substantially over the entire surface without gaps, and can be fixed if necessary.

Of course, the method of manufacturing the split tube 92a is not limited to the above-described modes. That is, for example, after molding a resin tube into a predetermined shape (that is, a shape in which the outer diameter dimension decreases toward the distal end side, which is the shape shown in FIG. 14 in this embodiment), the resin tube is fitted over the outer tube 72. In such a case, the proximal end surface of the distal end cover portion 86 and the distal end surface of the outer tube 72 may be in contact with each other in a non-fixed state or a fixed state. Alternatively, after a resin tube having a substantially constant diameter is fitted around the outer tube 72, the resin tube may be subjected to diameter reduction processing such as by heating to obtain the shape shown in FIG.

A wire 98 with a filter shown in FIG. 16 is attached to the delivery catheter 60 shaped as described above. The filter-equipped wire 98 has a longitudinal shape as a whole and includes a long wire portion 100 . A filter portion 102 is provided at the tip portion of the wire portion 100 , and the wire portion 100 is divided by the filter portion 102 . In other words, the wire portion 100 extends from the distal end and proximal end of the filter portion 102 . On the other hand, the proximal end portion of the wire portion 100 serves as a proximal end portion 104 to be gripped and operated by the user.

The wire portion 100 has an axial dimension longer than that of the delivery catheter 60 and is made of, for example, synthetic resin or stainless steel having a certain degree of flexibility. In this embodiment, the stainless steel extends continuously in the axial direction and has some degree of flexibility. The wire portion 100 has a diameter smaller than the inner diameter of the distal shaft 64 , so that the wire portion 100 can be inserted into the inner hole of the distal shaft 64 .

In the wire portion 100, annular contrast rings 106a and 106b are externally inserted on both ends of the filter portion 102, and the base end side of the contrast ring 106a on the distal side is inserted into the inner hole of the distal shaft 64. Thus, it is made slidable inside the distal shaft 64 . The filter portion 102 has a tubular shape having a spiral structure as a whole, and is made of Ni—Ti alloy in this embodiment. Further, a synthetic resin made of non-woven fabric or woven or knitted fabric made of a biocompatible material such as polyurethane is provided on the distal end side of the helical portion of the filter section 102 so that blood or the like can pass through the filter section 102. On the other hand, debris such as thrombi and blood clots in blood cannot pass through the filter section 102 . The outer diameter of the imaging rings 106a and 106b is smaller than the inner diameter of the distal end cover portion 86 of the covering tube 82. As shown in FIG.

Furthermore, a stopper 108 is externally fitted and fixed to the wire portion 100 on the distal side of the imaging ring 106a on the distal side. The stopper 108 has a tapered tubular shape with an outer diameter that decreases toward the distal end. is larger than the inner diameter dimension of the tip cover portion 86 in .

The embolus removal catheter 62 of the present embodiment is constructed by inserting the filter-equipped wire 98 shaped as described above into the delivery catheter 60 . Specifically, the proximal end of the wire 98 with a filter is inserted from the distal end side opening of the distal end cover portion 86 in the covering tube 82 of the delivery catheter 60 , and the proximal end of the wire 98 with a filter is inserted into the distal shaft 64 . It protrudes to the proximal side from a port portion 68 which is a proximal side opening of. On the other hand, the filter section 102, the contrast rings 106a and 106b, and the stopper 108 provided at the distal end portion of the wire 98 with filter are located on the distal side of the covering tube 82 relative to the distal end cover section 86. FIG.

When using the embolus removal catheter 62 structured as described above, first, for example, from the state shown in FIG. pull to the side. As a result, the wire portion 100 inserted through the distal shaft 64 and the inner hole of the outer tube 72 is pulled toward the proximal end side, and the filter portion 102 and the imaging rings 106a and 106b protruding from the distal end of the delivery catheter 60 are pulled toward the outer tube. Housed within 72 . At this time, since the filter portion 102 is made of an elastic Ni--Ti alloy, the filter portion 102 is accommodated in the outer tube 72 while being elastically deformed. The pulling of the filter-equipped wire 98 is limited by the contact of the proximal end of the stopper 108 with the distal end cover portion 86 of the cover tube 82 . In the present embodiment, since the tip cover portion 86 has a larger thickness toward the inner periphery, the stopper 108 can be made smaller in diameter. It is also possible to improve insertability by reducing insertion resistance.

Then, the embolus removing catheter 62 with the filter portion 102 accommodated in the outer tube 72 is inserted into a predetermined position through a guiding catheter previously placed in the blood vessel. After that, in the embolus removal catheter 62 that has reached the predetermined position, the filter-equipped wire 98 is fixed, and the delivery catheter 60 is pulled out from the proximal end side, so that the filter-equipped wire 98 is indwelled at the predetermined position in the blood vessel. . At this time, by exposing the filter portion 102 from the outer tube 72, the elastic restoring action of the filter portion 102 allows the filter portion 102 to be indwelled in the blood vessel in an expanded state as shown in FIGS. . As a result, debris such as thrombi and blood clots in blood vessels are efficiently captured by the filter section 102 .

After such treatment, a conventionally known withdrawal catheter is used to withdraw the wire 98 with a filter indwelled in the blood vessel, thus completing the treatment.

In the delivery catheter 60 of the present embodiment having the structure described above, the covering tube 82 includes a distal end cover portion 86 that covers the distal end side of the outer tube 72. Particularly in the present embodiment, the distal end cover portion Since the inner diameter dimension of 86 is substantially equal to the inner diameter dimension of outer tube 72 , axial protrusion of reinforcing braid 74 from outer tube 72 can be more reliably prevented. A curved inclined surface 90 is provided on the outer peripheral surface of the tip cover portion 86, and the outer diameter of the covering tube 82 gradually decreases toward the tip side, so that the delivery catheter 60 can be inserted into the blood vessel. It is possible to prevent the tube from being caught on the blood vessel wall, thereby improving the insertability.

Further, in the present embodiment, the radial width dimension _W1 of the tip cover portion 86 of the covering tube 82 is the radial width of the portion of the covering tube 82 other than the tip cover portion 86, that is, the portion covering the outer peripheral surface of the outer tube 72. Since it is larger than the dimension W ₂ (W ₂ <W ₁ ), the diameter of the delivery catheter 60 can be reduced and the axial protrusion of the reinforcing braid 74 can be more effectively prevented.

Furthermore, in this embodiment, since the contrast marker 78 is provided at the distal end portion of the outer tube 72 , the insertion operation of the delivery catheter 60 can be performed while confirming the distal end position of the outer tube 72 . In particular, in the present embodiment, since the contrast marker 78 is covered with the covering tube 82, the outer diameter of the delivery catheter 60 does not change abruptly, and catching on the blood vessel wall or the like is suppressed. It is possible to improve the quality.

Since the contrast marker 78 is provided at the distal end portion of the outer tube 72, by reducing the axial dimension of the distal end cover portion 86 projecting from the outer tube 72 to the distal end, X-ray confirmation can be performed during surgery. The deviation between the position of the distal end portion of the outer tube 72 and the actual position of the distal end portion of the delivery catheter 60 can be kept small, and the work of inserting the delivery catheter 60 into the blood vessel can be performed while grasping the position of the distal end portion of the delivery catheter 60 more accurately. is also possible.

Although the embodiments of the present invention have been described in detail above, the present invention is not to be construed as being limited by the above specific descriptions.

For example, in the fourth embodiment, the distal end cover portion of the covering tube has a diameter smaller than that of the portion covering the outer peripheral surface of the braid tube (outer tube 72) on the base end side, and the braid tube when viewed in the axial direction. It is not limited to the shape described in the fourth embodiment as long as it overlaps with the tip side end face of the. As a specific example, in the catheter 110 shown in FIG. 17, the inner diameter dimension of the distal end cover portion 114 of the covering tube 112 is gradually reduced toward the distal end side in the axial direction. In particular, in this aspect, the inner and outer peripheral surfaces of the tip cover portion 114 have tapered surfaces that are inclined at a substantially constant angle of inclination, and the tapered portion whose outer diameter and inner diameter gradually decrease toward the projecting tip. 116. Further, at the tip of the tapered portion 116, a small-diameter straight portion 118 is provided that protrudes toward the tip side substantially parallel to the axial direction. The axial dimension of the straight portion 118 is not particularly limited. There is a possibility that the position of the distal end of the catheter 110 may become difficult to grasp when the catheter 110 is inserted. Furthermore, in the fourth embodiment, the proximal end surface of the distal end cover portion 86 and the distal end surface of the outer tube 72 were in contact with each other, but as in this specific example, the proximal end of the distal end cover portion 114 is in contact with each other. A gap may be provided between the side end surface and the distal end surface of the outer tube 72 so as to be separated from each other.

In addition, in the fourth embodiment and this aspect, the front end cover portions 86 and 114 have the outer diameter dimension gradually reduced toward the projecting front end side, but the outer diameter dimension may be reduced stepwise. Of course, the outer diameter dimension of the tip cover portion need not be reduced toward the projecting tip side, and may be substantially constant in the axial direction. In addition, it is preferable that the front end cover portion of the covering tube overlaps so as to completely cover all the reinforcing blades when viewed in the axial direction of the braid tube. For example, some of the reinforcing blades on the axial end surface of the braid tube are not covered with the tip cover portion, or the end surface of the reinforcing blade is partially covered with the tip cover portion. A mode, etc., in which there is

Also, the inner diameter of the tip cover portion is preferably substantially equal to or smaller than the inner diameter of the braided tube (outer tube 72). This can effectively prevent the reinforcing blade from protruding in the axial direction. However, the inner diameter of the tip cover portion may be larger than the inner diameter of the braided tube. That is, in the fourth embodiment, the distal end cover portion 86 overlaps substantially the entire distal end surface of the outer tube 72 when viewed in the axial direction. preferred. However, in the present invention, the tip cover portion is not essential.

Furthermore, in the first embodiment, the distal end tube 28a and the proximal end tube 28b are provided on both sides of the outer tube 20, and the distal end tube 28a is any one of the first to tenth tubes. However, instead of the distal end tube, the proximal end tube may be configured according to any one of the first to tenth aspects, and both end tubes may be configured according to the first to tenth aspects. It may be constructed according to any of the tenth aspects. Of course, the end tubes need not be provided on both sides of the braided tube (outer tube 20), and may be provided on either side. Even if the end tubes are provided on both sides of the braided tube (outer tube 20), it is preferable that at least one of them has a structure according to any one of the first to tenth aspects, as described above. be. However, in the present invention, end tubes are not essential.

Further, in the first to third embodiments, the relative movement of the welding die 36 and the core rod 34 and the welding of the covering tube 30 do not have to be performed in the order of (a) to (c) of FIG. For example, it may be performed in the opposite direction, or may be performed in random order.

Furthermore, in the above-described embodiment, the outer tube 20, the distal end tube 28a, and the covering tube 30 all have a tubular shape extending substantially straight in the axial direction, but these shapes are not limited in any way. That is, the shape of the catheter according to the present invention is not limited at all. Therefore, the structure according to the present invention can also be applied to the recovery catheters described in JP-A-2008-35923 and JP-A-2009-178518. Furthermore, in the fourth embodiment, in the embolus removal catheter 62, the wire portion 100 of the wire 98 with a filter is inserted from the distal opening of the outer tube 72 to the proximal opening of the distal shaft 64 ( Although it protrudes proximally from the port portion 68 ), it may protrude proximally from the proximal side opening of the connector portion 70 through the distal shaft 64 and the proximal shaft 66 . It should be noted that the catheter according to the present invention is not limited to the filter recovery catheters exemplified in the first to third embodiments and the embolus removal filter delivery catheters exemplified in the fourth embodiment. Various catheters can be employed, such as delivery catheters for delivering stents, aspiration and balloon catheters, guiding catheters, atherectomy angioplasty catheters, and catheters with multiple lumens.

Furthermore, in the first to third embodiments, the butted end surfaces of the outer tube 20 and the tip end tube 28a are in contact with each other, but the blade tube (outer tube 20) and the braided tube (outer tube 20) are in contact with each other before the covering tube is welded. A slight gap may be provided between the end tubes. That is, the covering tube may be welded so that the molten resin may enter between the braided tube and the end tube, and the braided tube and the end tube may not be directly welded.

The welding of the covering tube is not limited to heat welding, and may be ultrasonic welding. Even in the case of ultrasonic welding, the welding conditions are appropriately set so that the degree of welding to the outer end portion of the end tube in the axial direction of the covering tube is such that the braid tube and the end tube of the covering tube are butted together. It is sufficient if the degree of welding is greater than that of the portion. In the case of heat welding, it is also possible to move the welding mold continuously in the axial direction with respect to each tube without fixing the position of the welding mold. The amount of heat applied to each portion of each tube may be adjusted by controlling the speed of movement in the axial direction. Furthermore, the heating means for heat welding is not limited to the welding mold. Of course, the covering tube is not limited to being welded to the outer peripheral surface of the braided tube or the end tube, and may be adhered, for example.

In addition, in the first to third embodiments, the degree of welding is varied by varying the amount of heat applied during welding, but the present invention is not limited to such a mode. That is, even if the amount of heat to be applied is the same, it is possible to vary the degree of welding by using different materials constituting the tube, such as using materials that are easy to weld and materials that are difficult to weld. Furthermore, even when the amount of heat applied during welding is varied, not only the heating temperature but also the heating time may be varied as in the first embodiment, or both may be varied. Also, the degree of welding may be controlled by appropriately cooling the welding mold and/or the tube with air or the like according to the welding portion in the axial direction. Furthermore, it is also possible to adjust the degree of welding by appropriately selecting the material of the reinforcing blade. In addition, prior to welding, appropriate pretreatments such as wiping the surface of the welded portion of the braided tube, end tube, and covering tube with ethanol, or performing blasting on the surface can be applied to, for example, each tube. It is also possible to adjust the degree of welding by modifying the surface.

Furthermore, in the first to third embodiments, the covering tube 30 is composed of split tubes 32a, 32b, 32c, and 32d having substantially the same structure. The covering tube 82 is composed of the split tubes 92a, 92b, 92c, and 92d having the same structure, but at least one of the split tubes has different characteristics relative to the other split tubes. may Here, the properties refer to chemical, physical, or mechanical properties such as material, strength, and rigidity. Therefore, for example, by setting the rigidity of the split tubes at both ends to be small and adopting split tubes whose stiffness gradually increases inward in the axial direction, a catheter can be efficiently manufactured according to the rigidity of the split tubes. can be In addition, for example, if the stiffness of the split tube at the distal end is reduced and a split tube whose rigidity gradually increases toward the proximal end is adopted, a catheter that conforms to the rigidity of the split tube can be efficiently manufactured. .

Furthermore, in the above-described embodiment, the outer circumference of the contrast marker 26 is covered with the covering tubes 30 and 82, but the contrast marker may be fitted and fixed to the outer circumference of the covering tube. However, the contrast marker is not essential in the present invention.

Further, the reinforcing braid employed in the braid tube is not limited to a mesh shape, and may be spiral, for example, extending continuously in the axial direction. Further, the material of the braided wire that constitutes the reinforcing braid is not limited to metal, and may be made of synthetic resin, for example. In this specification, the wire constituting the reinforcing braid is referred to as a braided wire for easy understanding, but the interpretation is not limited to the braided structure.

10 (filter) recovery catheter (catheter)
12 Distal shaft 14 Proximal shaft 16 Port part 18 Connector part 20 Outer tube (blade tube)
22 Reinforcement braid 24 Cylindrical wall 26 Contrast marker 28 End tube 28a Distal end tube 28b Base end tube 30 Covering tubes 32a, 32b, 32c, 32d Divided tube 34 Core rod 36 Welding molds 40, 50 (filter) recovery catheter (catheter) for
60 delivery catheter (catheter)
62 embolus removal catheter 64 distal shaft 66 proximal shaft 68 port section 70 connector section 72 outer tube (braided tube)
74 Reinforcing braid 76 Cylindrical wall 78 Contrast marker 80 End tube 82 Covering tube 84 Inner circumferential surface 86 Tip cover portion (protruding portion of covering tube)
88 Tapered portion 90 Curved inclined surfaces 92a, 92b, 92c, 92d Divided tube 92a' Resin tube 94 Stepped pin 96 Extension plate 98 Wire with filter 100 Wire portion 102 Filter portion 104 Base end portions 106a, 106b Contrast ring 108 Stopper 110 Catheter 112 Covering tube 114 Tip cover portion (protruding portion of covering tube)
116 tapered portion 118 straight portion

Claims (10)

A catheter comprising a braided tube having reinforcing braids,
An end tube is arranged on at least one end of the braided tube with its axial end faces abutted against each other, and a covering tube is fitted over both the braided tube and the end tube to extend over both the tubes. While it is welded to the outer peripheral surface of
A catheter in which the covering tube is welded to the axially outer end portion of the end tube to a greater degree than the covering tube to the butted portion of the braided tube and the end tube. 2. The catheter of claim 1, wherein the axially outer ends of the end tube and the cap tube are axially co-located. 2. The catheter of claim 1, wherein said cap tube projects axially outwardly beyond said end tubes. 2. The catheter of claim 1, wherein said end tube projects axially outwardly beyond said cap tube. The catheter according to any one of claims 1 to 4, wherein the covering tube is thinner than the braided tube. The catheter according to any one of claims 1 to 5, wherein said reinforcing braid is made of metal. The catheter according to any one of claims 1 to 6, wherein the inner diameter dimension of the braided tube and the inner diameter dimension of the end tube at the butted portion of the braided tube and the end tube are equal. The catheter according to any one of claims 1 to 7, which is a filter recovery catheter for recovering a filter placed in a blood vessel. A method for manufacturing a catheter having a braided tube having reinforcing braids, the method comprising:
An end tube is placed on at least one end side of the braided tube, the axial end surfaces are butted against each other, and a covering tube is inserted over both the braided tube and the end tube, and The amount of heat applied to the outer end portion of the end tube in the covering tube in the axial direction when the braided tube and the covering tube of the covering tube are heated and welded together A method for manufacturing a catheter in which the amount of heat applied to the abutting portion with the end tube is greater than that applied. The amount of heat applied to the portion of the covering tube axially inner than the abutting portion of the braided tube with the end tube when heating and welding the outer portion of the covering tube of the braided tube and the end tube is greater than the amount of heat applied to the abutting portion of the braided tube and the end tube in the covering tube.

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