JP5605636B2 - Balloon catheter - Google Patents

Description

  The present invention relates to a balloon catheter that expands a stenosis portion of a blood vessel with a balloon that deforms by supplying and discharging pressure fluid, and more particularly, a balloon provided with a balloon cover that is externally fitted to a deflated balloon to protect the balloon. It relates to a catheter.

  Conventionally, percutaneous angioplasty using a balloon catheter is known as one of the methods for treating stenosis or occlusion of blood vessels due to atheroma or the like. The balloon catheter is provided with a balloon at the distal end portion of the catheter shaft. By supplying a pressure fluid to the balloon inserted in the stenosis part of the blood vessel, the stenosis part of the blood vessel is pushed and expanded by the balloon. It is used for the purpose of recovering.

  Moreover, in the balloon catheter, a balloon cover for holding the balloon in a deflated state is employed for transportation and storage before use. The balloon cover has a cylindrical shape, and is fitted on the folded balloon to prevent the balloon from being unnecessarily expanded. Furthermore, a balloon catheter having a balloon cover for wrapping is also known in order to keep the balloon in a deflated state when the balloon catheter once used during the operation is reused.

  By the way, as a balloon cover for wrapping, a balloon cover that is externally fitted to the balloon before use of the balloon catheter is generally used. This balloon cover is removed from the catheter shaft when the balloon catheter is used. It was. Then, when the balloon extracted from the blood vessel is folded, the balloon is re-inserted into the catheter shaft and fitted onto the balloon to hold the balloon in a contracted state.

  However, if the balloon cover once removed is used for balloon wrapping in this way, it may be difficult to use it immediately when necessary due to loss of the removed balloon cover or contamination due to falling onto the floor. is there.

  Therefore, Utility Model Registration No. 3115667 (Patent Document 1) discloses a structure that can be moved and held proximal to the catheter shaft without removing the balloon cover (rewrap device) from the catheter shaft. .

  However, the practitioner grasps the connector provided at the proximal end of the catheter shaft and operates the catheter by grasping the proximal end of the catheter shaft and the protective cover provided thereon with a fingertip. If the balloon cover is held at the proximal end of the catheter shaft, the practitioner may accidentally pick the balloon cover with the fingertip. As a result, the balloon cover may interfere with the catheter operation and may adversely affect the accuracy of the procedure. In particular, since the balloon cover for wrapping described in Patent Document 1 is extrapolated on the outer peripheral surface of the protective cover, it interferes with the procedure, and from the protective cover by touching the operator's fingers. There was also a problem that it was easy to come off.

  Patent Document 1 discloses a structure (FIG. 2 of Patent Document 1) in which a balloon cover is positioned in an extrapolated state with respect to a protective cover protruding from the connector toward the catheter shaft, or a locking piece protruding from the connector. Has proposed a structure in which the balloon cover is locked and positioned (FIG. 5 of Patent Document 1). However, in any case, the balloon cover for wrapping is extrapolated on the outer peripheral surface of the protective cover, and the balloon cover is held at the proximal end of the catheter shaft. It did not give any solution to the problem of causing troubles and being easy to remove from the protective cover during the procedure.

Utility Model Registration No. 3115667

  The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is that a balloon cover used for balloon re-folding (re-wrapping) can be stably catheterized without interfering with the procedure of the operator. Locating and holding on the shaft.

That is, according to the first aspect of the present invention, a balloon is provided at the distal end of the catheter shaft, and a connector is provided at the proximal end of the catheter shaft. In a balloon catheter in which pressure fluid is supplied to and discharged from the balloon, the balloon catheter is formed of a flexible material and extends from the connector onto the catheter shaft so as to cover a connection side end portion of the catheter shaft to the connector. A cylindrical protective cover is provided, and a cylindrical balloon cover that is externally fitted to the deflated balloon to protect the balloon is provided, and the cylindrical protective cover is provided at the proximal end of the balloon cover. while engagement portion is fitted into the opening of the distal end side of the cover is locked is provided, said tubular protection cover Wherein the gap is formed between the peripheral surface and the outer peripheral surface of the catheter shaft.

  According to the balloon catheter having the structure according to the first aspect as described above, the balloon cover for wrapping is fitted into the cylindrical protective cover provided at the proximal end of the catheter shaft, and the locking portion is cylindrical. The balloon cover is positioned and held at the proximal end of the catheter shaft by being locked to the protective cover. As described above, since the balloon cover is inserted into the cylindrical protective cover, when the practitioner operates the catheter by grasping the proximal end of the catheter shaft with the fingertip, the balloon cover may interfere with the procedure. The practitioner can perform the procedure with high accuracy.

In addition, since the balloon cover is locked to the cylindrical protective cover at the locking portion, even when the operator's fingers touch the balloon cover, the balloon cover can be easily removed from the cylindrical protective cover. Rather, it is stably positioned and held at the proximal end of the catheter shaft. Furthermore, according to the first aspect, since the gap is formed between the tubular protective cover and the catheter shaft, the locking portion of the balloon cover can be easily disposed between the tubular protective cover and the catheter shaft. It is inserted and held. Therefore, even when the balloon is rewrapped a plurality of times in one operation, the positioning and holding of the balloon cover to the cylindrical protective cover can be smoothly realized and the operation time can be prevented from becoming longer. .

  According to a second aspect of the present invention, in the balloon catheter described in the first aspect, the engaging portion of the balloon cover is formed with an enlarged diameter portion whose outer diameter gradually increases outward in the axial direction. It is what has been.

  According to the second aspect, the expanded diameter portion of the locking portion is fitted into the cylindrical protective cover, whereby the expanded diameter portion is locked to the inner peripheral surface of the cylindrical protective cover, and the balloon cover is protected in the cylindrical shape. Positioning and holding is stable with respect to the cover. In addition, the latching | locking part which has an enlarged diameter part can be easily formed by expanding the diameter of the edge part of the balloon cover made into the cylindrical shape.

According to a third aspect of the present invention, in the balloon catheter described in the first or second aspect, the cylindrical protective cover is softer than the balloon cover.

According to the third aspect, the balloon cover is protected and maintained in a contracted state by the balloon cover, and the balloon cover is relatively easily attached to and detached from the cylindrical protective cover, so that the rewrap operation is easily performed. be able to.

According to a fourth aspect of the present invention, in the balloon catheter described in any one of the first to third aspects, the inner peripheral surface of the cylindrical protective cover is gradually contracted toward the opening on the distal end side. A tapered inner peripheral surface is formed.

According to the 4th aspect, the latching part of a balloon cover contact | abuts to the internal peripheral surface of a cylindrical protective cover, and the removal to the distal side of a balloon cover is prevented. As described above, since the balloon cover can be positioned and held at the proximal end of the catheter shaft by an extremely simple structure, a balloon catheter having a structure according to the present invention can be easily manufactured.

  According to the present invention, since the balloon cover for wrapping the balloon is held without being detached from the catheter shaft, the balloon cover can be used promptly when necessary, and the workability is improved. Figured. Moreover, the balloon cover is stably held at the proximal end of the catheter shaft by the locking portion being locked to the cylindrical protective cover, and the practitioner mistakenly holds the balloon cover during the procedure. Even in the case of picking, the adverse effect on the catheter operation is suppressed and the accuracy of the procedure is maintained, and it is also possible to prevent the balloon cover from being easily removed and obstructing the procedure.

The figure which shows schematically the balloon catheter as one Embodiment of this invention. Sectional drawing which expands and shows the principal part of the balloon catheter shown by FIG. It is a figure explaining the usage method of the balloon catheter shown by FIG. 1, Comprising: (a) is the wrapping state before use, (b) is the state which bulged and deform | transformed the balloon in the use state, (c). Shows the state in which the balloon cover is detached from the cylindrical protective cover in the balloon deflated state after use, and (d) shows the wrapping state after use.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 schematically shows a balloon catheter 10 as an embodiment of the present invention. As shown in FIG. 1, the balloon catheter 10 has a long and flexible catheter shaft 12, and a balloon 14 is provided at a distal portion of the catheter shaft 12. A connector 16 is provided on the proximal side. Then, the distal end side of the catheter shaft 12 is inserted into the blood vessel from the wrist or thigh of the human body, and the balloon 14 is inflated in a state where it reaches the treatment site such as the coronary artery. The blood flow is restored.

  More specifically, the catheter shaft 12 has a structure in which a small inner tube-shaped first inner shaft 20 and a second inner shaft 22 are inserted through a tube-shaped outer shaft 18. The outer shaft 18 is formed in a long tubular shape that extends continuously with a substantially constant circular cross-sectional shape, and has a thickness that can be inserted into a blood vessel to be inserted and a sufficient length to reach a target treatment site. ing. The outer shaft 18 is formed of a soft material that can be bent along the blood vessel. For example, polyamide, vinyl chloride, polyurethane, polyimide, polyethylene, polyester elastomer, polypropylene, polytetrafluoroethylene, polyetheretherketone, A synthetic resin material such as polyvinylidene fluoride, a metal material such as stainless steel or a nickel-titanium alloy, and a combination thereof are preferably used.

  The first inner shaft 20 has a tubular shape that is longer and smaller in diameter than the outer shaft 18, and is formed of the same soft material as the outer shaft 18. The first inner shaft 20 is inserted through the outer shaft 18 and penetrates the outer shaft 18 and protrudes on both sides in the longitudinal direction. A first hub 24 that is hard and cylindrical is attached to the proximal end of the first inner shaft 20.

  A guide wire lumen 26 is formed by the lumen of the first inner shaft 20. The guide wire lumen 26 has a small-diameter, substantially circular cross section, opens at the distal end surface of the first inner shaft 20, and communicates with the outside on the proximal side through the first hub 24. Has been. A guide wire (not shown) is inserted into the guide wire lumen 26 so as to be removable. In the procedure, the guide wire is inserted into the blood vessel in advance prior to insertion of the catheter shaft 12 into the blood vessel. Thereafter, the first inner shaft 20 is extrapolated to the guide wire, and the catheter shaft 12 is inserted into the blood vessel along the guide wire, so that the distal end portion of the catheter shaft 12 can be smoothly reached to the stenosis site as the treatment target site. I can guide you.

  The second inner shaft 22 has a longer and smaller diameter than the outer shaft 18 and is formed of the same soft material as the outer shaft 18 and the first inner shaft 20. The second inner shaft 22 is inserted through the outer shaft 18, like the first inner shaft 20, and protrudes through the outer shaft 18 to both sides in the longitudinal direction. A second hub 28 that is rigid and cylindrical is attached to the proximal end of the second inner shaft 22.

  Further, a pressure adjusting lumen 30 as a lumen is formed by the lumen of the second inner shaft 22. The pressure adjusting lumen 30 is continuously formed over the entire length of the second inner shaft 22 with a substantially circular cross-section having a small diameter, and is open to the distal end surface of the second inner shaft 22. The second hub 28 communicates with the outside on the proximal side. The pressure adjusting lumen 30 has a distal opening that opens into an internal space of the balloon 14 to be described later, and a proximal opening that serves as pressure adjusting means (not shown) via the second hub 28. It is connected. Then, a pressure fluid such as air is supplied or discharged to the balloon 14 through the pressure adjusting lumen 30 by the pressure adjusting means, whereby the internal pressure of the balloon 14 is adjusted so that the balloon 14 is switched between the expanded state and the deflated state. It has become.

  The balloon 14 is a cylindrical or bag-shaped thin film body formed of a synthetic resin such as polyurethane or silicon resin, and is externally inserted into the tip portion of the first inner shaft 20 protruding from the outer shaft 18. , Disposed at the distal end of the catheter shaft 12. The proximal end of the balloon 14 is overlapped and fixed to the outer peripheral surface of the distal end of the outer shaft 18, and the distal end of the balloon 14 is attached to the outer peripheral surface of the distal end of the first inner shaft 20. It is overlapped and fixed. Thereby, a space sealed from the external space is formed between the balloon 14 and the first inner shaft 20, in other words, on the inner peripheral side of the balloon 14, and the second inner shaft is formed in the space. Twenty-two pressure adjusting lumens 30 communicate with each other. The pressure in the space is adjusted by the pressure adjusting means through the pressure adjusting lumen 30 so that the contracted state and the bulged state of the balloon 14 are switched.

  Note that a contrast marker (not shown) is attached to the first inner shaft 20 at a protruding portion from the outer shaft 18. This contrast marker is an annular or C-shaped member made of a metal material having radiopacity such as platinum-iridium alloy. Then, two contrast markers (not shown) are fixed to the insertion portion of the first inner shaft 20 to the balloon 14 so as to be separated from each other in the length direction, thereby the tip of the balloon 14 inserted into the body and The proximal end can be confirmed by fluoroscopy using X-rays.

  In the balloon catheter 10 before use, a wrapping cover 34 is attached to the balloon 14. The wrapping cover 34 has a thin, small-diameter, generally cylindrical shape, and is a hard member formed of a synthetic resin material, a metal material, or the like, and is prevented from being deformed by the action of an external force. The wrapping cover 34 is externally fitted to the balloon 14 folded in a contracted state, so that the balloon 14 is prevented from being unfolded and held in a folded state, and the balloon 14 is damaged or deformed by the action of an external force. Is prevented.

  On the other hand, a connector 16 is disposed at the proximal end of the catheter shaft 12. As shown in FIG. 2, the connector 16 is a rigid member having a substantially cylindrical shape, the proximal side of which is a large-diameter introduction portion 36, and its proximal end toward the proximal side. A guide portion 37 that gradually increases in diameter is provided. Further, the distal side of the connector 16 is a small-diameter mounting portion 38, and a locking groove 40 that opens to the outer peripheral surface and extends in the circumferential direction is formed at the proximal end thereof. The outer shaft 18 is inserted and fixed in the inner cavity of the attachment portion 38, and the first and second inner shafts 20 and 22 inserted from the proximal end side of the connector 16 through the introduction portion 36 are the outer shaft. It is led and inserted into 18 lumens. As a result, the catheter shaft 12 extends from the connector 16 toward the distal side.

  A cylindrical protective cover 42 is attached to the attachment portion 38 of the connector 16. The cylindrical protective cover 42 has a tapered cylindrical shape that gradually decreases in diameter toward the distal side, and has an inner peripheral surface that is a tapered inner peripheral surface and an outer peripheral surface that is a tapered outer peripheral surface. ing. Further, the inner diameter of the distal end of the cylindrical protective cover 42 is made larger than the outer diameter of the outer shaft 18 so as to be extrapolated with a predetermined gap 46 with respect to the outer shaft 18 as will be described later. It has become. The cylindrical protective cover 42 is made of an elastic material such as silicone rubber, and is sufficiently flexible as compared with the connector 16. Further, a locking projection 44 that protrudes toward the inner peripheral side is integrally formed at the proximal portion of the cylindrical protective cover 42. The cylindrical protective cover 42 desirably has a large surface frictional resistance, and a large friction coefficient is set by selecting a forming material, roughening the surface, or the like.

  The tubular protective cover 42 has a proximal portion that is extrapolated to the mounting portion 38 of the connector 16, and a locking projection 44 that fits into the locking groove 40 of the connector 16, and is distal to the connector 16. It is attached to protrude to the side. As a result, the cylindrical protective cover 42 is extrapolated so as to cover the connection portion between the catheter shaft 12 and the connector 16, and kinks are prevented from occurring at the proximal end of the catheter shaft 12.

  Further, the inner diameter dimension (minimum inner diameter dimension) of the distal end of the cylindrical protective cover 42 protruding from the connector 16 is larger than the outer diameter dimension of the outer shaft 18. Thus, a gap 46 is formed over the entire circumference between the inner peripheral surface of the distal portion of the cylindrical protective cover 42 and the outer peripheral surface of the outer shaft 18 of the catheter shaft 12. The distal end of the cylindrical protective cover 42 is desirably separated from the outer peripheral surface of the outer shaft 18 over the entire circumference, but may be in contact with the circumference partially and non-adheringly. .

  Further, a wrapping cover 48 as a balloon cover is externally attached to the catheter shaft 12. The wrapping cover 48 is formed of a synthetic resin material, a metal material, or the like, is harder than the cylindrical protective cover 42, and has a generally cylindrical portion with a small diameter as a whole. Furthermore, it has an inner diameter slightly larger than that of the wrapping cover 34, so that it can be easily fitted to the balloon 14 described later. The wrapping cover 48 is provided with a taper-shaped guide portion 50 that gradually increases in diameter outward in the axial direction, and has a tapered shape that gradually increases in diameter outward in the axial direction. Is provided at the proximal end. In short, the wrapping cover 48 has a cylindrical shape in which an axial intermediate portion has a substantially constant circular cross section, and both end portions have a tapered cylindrical shape whose diameter increases in a trumpet shape outward in the axial direction. The tapered cylindrical enlarged diameter portion provided at the proximal end is the locking portion 52 in this embodiment.

  The wrapping cover 48 is held at the proximal end of the catheter shaft 12. More specifically, the maximum outer diameter dimension R of the locking portion 52 provided at the proximal end of the wrapping cover 48 is larger than the minimum inner diameter dimension r of the cylindrical protective cover 42, and the cylinder It is set to such an extent that it can be easily fitted by the elastic deformation of the shape protective cover 42. The wrapping cover 48 that is extrapolated to the proximal end of the catheter shaft 12 is fitted with the locking portion 52 elastically expanding and deforming with respect to the cylindrical protective cover 42. Is positioned and held by contacting and locking with the inner peripheral surface of the cylindrical protective cover 42. In FIG. 2, the locking portion 52 of the wrapping cover 48 is externally fitted to the mounting portion 38 of the connector 16, but in this embodiment, the locking portion 52 is separated from the mounting portion 38. Even if it exists, the wrapping cover 48 is positioned and held by the locking of the locking portion 52 to the cylindrical protective cover 42.

  Prior to use, the balloon catheter 10 having such a structure is externally fitted to the balloon 14 in which the wrapping cover 34 is folded in a contracted state, as shown in FIG. When the balloon catheter 10 is used, the wrapping cover 34 is displaced from the balloon 14 to the distal side, and is removed from the catheter shaft 12 to be put into use. The balloon catheter 10 in the use state as described above is guided into the blood vessel by extrapolating the guide wire previously inserted into the blood vessel to the first inner shaft 20, and the balloon 14 is used for a stenosis site or the like in the blood vessel. It is inserted until the treatment point is reached. Then, at the blood vessel treatment site, as shown in FIG. 3B, a pressure fluid such as air or physiological saline is supplied to the balloon 14 through the second inner shaft 22, and the balloon 14 is inflated. By doing so, the balloon 14 is pressed against the blood vessel wall, and the expansion of the blood vessel diameter, the application of the drug, and the like at the treatment site are realized.

  After the treatment is completed, the pressure fluid is discharged from the balloon 14 through the second inner shaft 22, and the balloon 14 is deflated. The balloon catheter 10 is then withdrawn from the blood vessel but is refolded by the wrapping cover 48 to hold the balloon 14 in the collapsed deflated state when reused at another treatment site. That is, first, an external force is applied to the wrapping cover 48 locked to the cylindrical protective cover 42 at the proximal end of the catheter shaft 12 by hand or the like, so that the wrapping cover 48 extends from the cylindrical protective cover 42 to the distal side. Extracted. Next, as shown in FIG. 3 (c), the wrapping cover 48 moved distally along the catheter shaft 12 is moved as shown in FIG. 3 (d). The outer balloon 14 is externally fitted to the deflated balloon 14. As a result, the deflated balloon 14 is rewrapped by the wrapping cover 48, and unnecessary deployment of the balloon 14 is prevented by the wrapping cover 48. Further, since the balloon 14 is brazed in a folded state by the wrapping cover 48, the balloon 14 is held in a contracted state with a small diameter even after the wrapping cover 48 is removed again. Can be easily reinserted into the blood vessel.

  According to the balloon catheter 10 having such a wrapping cover 48, the wrapping cover 48 is held on the catheter shaft 12 without being detached from the catheter shaft 12, so that the wrapping cover 48 is lost or contaminated. Can be avoided. Therefore, the wrapping of the balloon 14 by the wrapping cover 48 can be performed quickly when necessary.

  The wrapping cover 48 is fitted and held on the inner peripheral side of the cylindrical protective cover 42 provided at the proximal end of the catheter shaft 12 in a non-use state removed from the balloon 14. In addition, the locking portion 52 provided on the wrapping cover 48 is abutted and locked to the inner peripheral surface of the cylindrical protective cover 42, so that the wrapping cover 48 is stable with respect to the cylindrical protective cover 42. Positioned and held. Therefore, even when the practitioner picks the wrapping cover 48 with his / her fingers, the relative movement of the wrapping cover 48 with respect to the catheter shaft 12 is prevented, and the accuracy of the procedure can be prevented from being lowered. Further, since the wrapping cover 48 is prevented from being detached from the cylindrical protective cover 42 and moving on the catheter shaft 12 during the procedure, the wrapping can be quickly performed when the balloon 14 needs to be wrapping. A cover 48 can be used.

  Further, a gap 46 is formed between the outer peripheral surface of the outer shaft 18 and the inner peripheral surface of the cylindrical protective cover 42, and the engaging portion 52 of the wrapping cover 48 is fitted into the cylindrical protective cover 42 through the gap 46. It is supposed to be. Therefore, the wrapping cover 48 is relatively easily fitted into the inner peripheral side of the cylindrical protective cover 42 and is positioned and held.

  Further, the inner peripheral surface of the cylindrical protective cover 42 is a tapered inner peripheral surface that decreases in diameter toward the distal side, and is outside the proximal end of the locking portion 52 provided on the wrapping cover 48. The diameter dimension R is made larger than the inner diameter dimension r of the distal end of the cylindrical protective cover 42. Thereby, the ease of fitting the wrapping cover 48 into the cylindrical protective cover 42 is realized by the gap 46, and the retaining portion 52 and the cylindrical shape prevent the detaching cover 48 from coming off from the cylindrical protective cover 42. The contact cover of the protective cover 42 is realized with higher reliability.

  Further, the locking portion 52 of the wrapping cover 48 is formed by making the proximal end of the substantially cylindrical wrapping cover 48 into a tapered cylindrical shape that gradually increases in diameter toward the proximal side. Therefore, a sufficient positioning action can be obtained with the locking portion 52 having a simple shape that is easy to make without significantly complicating the structure.

  On the other hand, the distal end of the wrapping cover 48 is provided with a tapered cylindrical guide portion 50 that gradually increases in diameter toward the distal side, and the balloon 14 contracted by discharge of the pressure fluid is provided in the guide portion 50. The taper-shaped inner peripheral surface guides and is accommodated in the central cavity of the wrapping cover 48. Thereby, the external fitting operation | work to the balloon 14 of the wrapping cover 48 is performed easily, the balloon 14 can be wrapping with high reliability, and shortening of treatment time can also be implement | achieved.

  Further, relative displacement of the cylindrical protective cover 42 with respect to the connector 16 is restricted by fitting of the locking protrusions 44 with the locking grooves 40 of the connector 16. Moreover, the cylindrical protective cover 42 is formed of an elastic body that is more flexible than the connector 16, and the proximal end portion of the cylindrical protective cover 42 is fitted to the attachment portion 38 of the connector 16 with a tight margin. Has been. Therefore, the tubular protective cover 42 is prevented from being detached from the connector 16 to the distal side, and the tubular protective cover 42 is stably positioned with respect to the connector 16. As a result, the wrapping cover 48 held by the cylindrical protective cover 42 is stably positioned with respect to the catheter shaft 12 and the connector 16.

  Further, since the wrapping cover 48 is harder than the cylindrical protective cover 42, the wrapping cover 48 is fitted into the cylindrical protective cover 42 while expanding the cylindrical protective cover 42, so that the cylindrical protective cover Positioning and holding force based on the elastic force 42 is exhibited. In addition, since the wrapping cover 48 is relatively hard, the rewrapped balloon 14 is sufficiently protected by the wrapping cover 48 and is brought into contact with other members (such as other surgical instruments). Damage to the balloon 14 is prevented.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the structure of the locking portion provided in the balloon cover is not limited to that of the locking portion 52 provided in the wrapping cover 48 of the above embodiment. Specifically, for example, a flange-shaped (annular plate-shaped) locking portion that extends in a direction substantially perpendicular to the axis at the proximal end of the balloon-shaped balloon cover may be employed. Moreover, the latching | locking part does not need to be provided continuously over the perimeter, for example, the protrusion-shaped latching | locking part which protrudes to an outer peripheral side in one place or several places on the periphery of a balloon cover is provided. It may be formed.

  Moreover, in the said embodiment, although the proximal end (locking part 52) of the wrapping cover 48 was made into the taper cylinder shape diameter-expanded toward the proximal side, the outer peripheral surface of the proximal end of a balloon cover is If it is made into the taper shape of the reverse direction which diameter-reduces toward the proximal side, the fitting to the cylindrical protective cover 42 will become easy. That is, for example, the outer peripheral surface of the proximal end is a tapered portion that gradually decreases in diameter toward the proximal side, and the distal end of the tapered portion projects to the outer peripheral side to form a step. A balloon cover, structured like a reverse fold, can also be realized. According to this, since the proximal side has a small diameter, the balloon cover can be easily fitted into the cylindrical protective cover 42, and the distal end of the tapered portion is the inner peripheral surface of the cylindrical protective cover 42. The balloon cover is stably positioned and held with respect to the cylindrical protective cover 42 by being brought into contact with and locked to. In addition, it is also possible to obtain a retaining effect more effectively by providing a protrusion that engages with a step formed at the distal end of the tapered portion on the inner peripheral surface of the cylindrical protective cover 42.

  In the above embodiment, the balloon cover is the wrapping cover 48 used only for wrapping the balloon 14, and the wrapping cover 34 that protects the balloon 14 before using the balloon catheter 10 is the wrapping cover 48. Although provided separately, one balloon cover may be used as both the wrapping cover and the wrapping cover. Specifically, for example, a wrapping cover 48 as a balloon cover may be externally fitted to the balloon 14 before using the balloon catheter 10 and also serve as a wrapping cover. In this case, when the balloon catheter 10 is used, the wrapping cover 48 is displaced proximally from the balloon 14 and held at the proximal end of the catheter shaft 12, and at the time of wrapping, the wrapping cover 48 is attached to the balloon. The balloon 14 is held in a contracted state by being externally fitted to the lens 14.

  Further, the cylindrical protective cover is not necessarily limited to the tapered cylindrical shape that gradually decreases in diameter toward the distal side. For example, the cylindrical protective cover has a cylindrical shape and protrudes toward the inner peripheral side in the opening on the distal side. It is also possible to employ a structure provided with a protrusion for engagement. Furthermore, when the inner peripheral surface of the cylindrical protective cover is a tapered inner peripheral surface, the outer peripheral surface may be a cylindrical shape or a reverse tapered shape, and the inner peripheral surface and the outer peripheral surface are made into corresponding shapes. You don't have to.

  Further, the structure of the connector disposed at the proximal end of the catheter shaft 12 is not limited to the specific structure shown in the embodiment. As the connector, for example, a general Y-shaped connector (a connector having a structure in which the distal side has a substantially cylindrical shape and the proximal side branches into two branches) can be adopted. Also in this case, if the cylindrical protective cover 42 is attached to the distal end of the Y-shaped connector and the wrapping cover 48 is fixedly held by the cylindrical protective cover 42, the effect of the present invention is achieved. Effectively demonstrated.

  In the balloon catheter 10, the catheter shaft 12 is formed by inserting the separate inner shafts 20 and 22 through the outer shaft 18, but the catheter shaft is formed by a single shaft having a double lumen structure, for example. May be. Needless to say, the catheter shaft may be formed by a single shaft having three or more lumens.

  In the above embodiment, the over-the-wire type balloon catheter 10 is illustrated, but the present invention is also applicable to a rapid exchange (monorail) type balloon catheter.

10: balloon catheter, 12: catheter shaft, 14: balloon, 30: pressure adjusting lumen (lumen), 42: cylindrical protective cover, 46: gap, 48: wrapping cover (balloon cover), 52: locking portion

Claims (4)

A balloon is provided at the distal end of the catheter shaft, and a connector is provided at the proximal end of the catheter shaft, and pressure fluid is supplied to and discharged from the connector side through the lumen of the catheter shaft. In balloon catheters,
A cylindrical protective cover is formed of a flexible material, extends from the connector onto the catheter shaft, and covers a connection side end of the catheter shaft to the connector. A cylindrical balloon cover that is externally fitted to the balloon and protects the balloon is provided. The proximal end of the balloon cover is fitted and locked to the opening on the distal side of the cylindrical protective cover. While the locking part is provided ,
A balloon catheter , wherein a gap is formed between an inner peripheral surface of the cylindrical protective cover and an outer peripheral surface of the catheter shaft .   2. The balloon catheter according to claim 1, wherein the locking portion of the balloon cover is formed with a diameter-expanded portion having an outer diameter that gradually increases outward in the axial direction. The balloon catheter according to claim 1 or 2 , wherein the cylindrical protective cover is softer than the balloon cover. The balloon catheter according to any one of claims 1 to 3 , wherein an inner peripheral surface of the cylindrical protective cover is a tapered inner peripheral surface that gradually decreases in diameter toward a distal opening.

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