WO2013076889A1 - Balloon catheter - Google Patents

Abstract

Provided is a catheter having a novel structure, the catheter being configured so that a propulsive force imparted from the proximal end of the catheter toward the distal end thereof can be efficiently transmitted to the distal end and so that a kink in the vicinity of the portion where a proximal shaft and a distal shaft are connected can be effectively prevented. A rapid exchange type balloon catheter (10) is configured so that a distal shaft (18) is configured so as to include an outer shaft (22) and an inner shaft (24). The balloon catheter (10) is provided with a wire material (36) protruding from the distal end of the proximal shaft (16) and affixed to the proximal shaft (16). The portion of the wire material (36) which protrudes from the proximal shaft (16) is affixed to the inner shaft (24) of the distal shaft (18). The wire material (36) is provided so as to be capable of being displaced relative to the outer shaft (22).

Description

Balloon catheter

The present invention relates to a balloon catheter having a balloon at a distal end portion of a shaft, and in particular, a distal shaft is composed of an outer shaft and an inner shaft, and a guide wire lumen is formed at the distal end portion of the shaft by the inner shaft. The present invention relates to a balloon catheter.

Conventionally, a balloon catheter has been used for, for example, percutaneous coronary intervention (PCI) or the like in order to push and expand a stenosis portion of a blood vessel or to expand and deform a stent. The balloon catheter has, for example, a structure in which a balloon is provided at a distal end portion of a shaft constituted by a proxy shaft and a distal shaft, and a supply / exhaust lumen communicating with the balloon is provided. . Then, when the fluid is supplied through the supply / discharge lumen while the balloon is inserted into the stenosis portion of the blood vessel, the balloon is inflated and the stenosis portion is expanded and deformed.

By the way, in addition to the over-the-wire type, the balloon catheter includes a rapid exchange type (RX type) in which a balloon can be easily exchanged. In this rapid exchange type balloon catheter, the distal shaft is composed of an outer shaft and an inner shaft, and the outer shaft has a supply / discharge lumen communicating with the balloon, and the inner shaft is the tip of the outer shaft. A guide wire lumen is formed in each of the surface and the outer peripheral surface of the intermediate portion so as to be opened and through which the guide wire is inserted.

However, in the rapid exchange type balloon catheter, since the inner shaft opens to the outer peripheral surface in the middle portion of the outer shaft, it has been required to improve the transmission efficiency of force when pushing the catheter forward.

Therefore, in Japanese Patent Application Laid-Open No. 2003-102841 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2002-736 (Patent Document 2), a reinforcing wire (core wire or reinforcing body) is arranged at the opening of the inner shaft. It has been proposed to efficiently transmit force from the proximal end to the distal end of the catheter by providing and ensuring the strength of the shaft.

However, in the structure described in Patent Document 1, since the distal end portion of the wire is fixed to both the outer shaft and the inner shaft, the force is transmitted from the wire to the outer shaft and the inner shaft in a distributed manner. In addition, the pushing force exerted on the inner shaft constituting the distal end of the catheter may be insufficient, and the deformation of the outer shaft affects the inner shaft and the transmission of force to the distal end of the catheter is hindered. There is also a case.

Furthermore, in the structure described in Patent Document 2, since the wire does not connect the proxy shaft and the distal shaft but only connects the outer shaft and the inner shaft, the proxy shaft is changed to the distal shaft. The transmission of this force tends to be insufficient, and the occurrence of kinks (bending) can also be a problem. In addition, since the outer shaft and the inner shaft are connected via the wire, unnecessary external force such as frictional force acting on the outer shaft is transmitted to the inner shaft via the wire, as in the structure of Patent Document 1. As a result, the efficient transmission of the pushing force may be hindered.

JP 2003-102841 A Japanese Patent Laid-Open No. 2002-736

The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is that the pushing force exerted from the proximal end toward the distal end is efficiently transmitted to the distal end of the catheter. Therefore, a catheter with a novel structure that achieves excellent penetration into a bent part or narrowed part such as a body lumen and effectively prevents kinking in the vicinity of the connection part of the proximal shaft and the distal shaft. It is to provide.

That is, according to the first aspect of the present invention, the proximal end portion of the shaft is constituted by a proximal shaft, the distal end portion of the shaft is constituted by a distal shaft, and the distal shaft is An outer shaft having a supply / discharge lumen and an inner shaft having a guide wire lumen are configured, and a balloon is provided at a distal end portion of the inner shaft, and the supply of the outer shaft to the balloon is provided. In the balloon catheter in which the drain lumen is communicated, a wire protruding from the distal end of the proxy shaft is provided, and the wire is fixed to the proxy shaft, while the wire shaft is fixed to the proxy shaft. The protruding portion is fixed to the inner shaft of the distal shaft, and the wire rod is attached to the outer shaft. And that are arranged to be relatively displaceable, characterized.

According to the rapid exchange type balloon catheter having the structure according to the first aspect as described above, the proximal shaft and the inner shaft are connected to each other by the wire, so that the proximal shaft is distant from the proximal end side of the proximal shaft. An external force (pushing force) exerted toward the distal end side is efficiently transmitted to the inner shaft through the wire. Therefore, the distal end portion of the balloon catheter provided with the balloon can be easily inserted into the stenosis part such as a blood vessel, and the expansion of the stenosis part by the balloon can be realized more stably.

Moreover, since the wire is fixed to the inner shaft but not to the outer shaft, the pushing force exerted on the wire from the proxy shaft is concentrated on the inner shaft without being distributed to the outer shaft. Communicated. Therefore, the pushing force is efficiently transmitted to the distal end of the balloon catheter, and the insertion property to the stenosis is improved. In addition, when an external force is applied to the outer shaft due to friction with the blood vessel wall, etc., transmission of the external force exerted on the outer shaft to the wire is avoided, and a pushing force input from the proximal end side is unnecessary. It is efficiently transmitted to the distal end side without being canceled by a large external force.

Further, in a general rapid exchange type balloon catheter, the strength in the axial direction of the distal shaft at the formation portion of the proximal end side opening portion of the guide wire lumen (port which is the proximal end side opening portion of the inner shaft). , It is easy to decrease, so that problems such as kinks may occur due to the action of the pushing force. However, in the rapid exchange type balloon catheter according to this aspect, since the wire material is arranged so as to straddle the port formation portion, the port formation portion of the distal shaft is reinforced with the wire material to prevent the occurrence of kinks, etc. Is done. As a result, the pushing force is prevented from being reduced by the deformation of the shaft, and excellent pushability is realized.

According to a second aspect of the present invention, in the balloon catheter described in the first aspect, the wire is formed of a metal material, and the distal shaft formed of the metal material on the inner shaft of the distal shaft. A fixing portion is provided, and the wire is fixed to the distal fixing portion.

According to the second aspect, since both the wire and the distal fixing portion are formed of a metal material, the wire and the distal fixing portion can be firmly fixed by means such as adhesion or welding. Therefore, even if a pushing force is exerted on the wire, the wire and the inner shaft are kept fixed, and the pushing force is effectively transmitted to the distal end side of the inner shaft.

A third aspect of the present invention is the balloon catheter described in the second aspect, wherein the distal fixing portion is a fixing ring fitted to the inner shaft.

According to the third aspect, since the distal fixing portion is a ring-shaped fixing ring, a fixing force of the fixing ring with respect to the inner shaft can be obtained easily and greatly, and the fixing ring with respect to the inner shaft can be obtained. A reduction in the transmission efficiency of the pushing force due to the positional deviation in the axial direction is prevented.

According to a fourth aspect of the present invention, in the balloon catheter described in any one of the first to third aspects, the wire is formed of a metal material, and the proxy shaft is formed of a metal material. A proximal fixing portion is provided, and the wire is fixed to the proximal fixing portion.

According to the fourth aspect, the proximal adhering portions of the wire and the proxy shaft are both formed of a metal material, and strong fixation is realized by adhesion or welding using a metal adhesive. Therefore, it is possible to prevent the transmission efficiency of the pushing force from being lowered due to the displacement of the wire relative to the proxy shaft.

According to the present invention, the proxy shaft and the inner shaft are connected to each other by the wire, and the pushing force toward the distal end exerted on the proxy shaft is transmitted to the inner shaft via the wire. It has become. Therefore, as compared with the case where the pushing force is transmitted from the proximal shaft to the inner shaft via the outer shaft, the pushing force is transmitted to the inner shaft more efficiently and can be easily inserted into the narrowed portion of the blood vessel. In addition, since the proximal end portion of the inner shaft (port forming portion of the guide wire lumen), which tends to be weakened in the rapid exchange type balloon catheter, is reinforced by the wire material, the occurrence of kinks in the portion is also avoided. The

The side view which shows the balloon catheter as one Embodiment of this invention in the expansion state of a balloon. The side view which expands and shows the principal part of the balloon catheter shown by FIG. The top view which expands and shows the principal part of the balloon catheter shown by FIG. IV-IV sectional drawing of FIG. In the balloon catheter shown in FIG. 1, the maximum value of the pushing force transmitted to the distal end is shown for each fixed position of the connecting wire and the inner shaft.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a rapid exchange type balloon catheter 10 as one embodiment of the present invention. The balloon catheter 10 includes a shaft 12 and a balloon 14 provided at a distal end portion of the shaft 12. In the following description, the right side in FIG. 1 is referred to as the proximal end, and the left side in FIG. 1 is referred to as the distal end.

More specifically, the shaft 12 includes a proximal shaft 16 constituting a proximal end portion and a distal shaft 18 constituting a distal end portion. The proxy shaft 16 is a member formed of a relatively rigid material having a tube shape formed of a small-diameter substantially cylinder. In this embodiment, the proxy shaft 16 is formed of a metal material such as stainless steel. A connector 20 is attached to the proximal end of the proximal shaft 16, and a central hole (lumen) of the proximal shaft 16 opens at the proximal end through the connector 20.

On the other hand, the distal shaft 18 is composed of an outer shaft 22 and an inner shaft 24 as shown in FIGS. The outer shaft 22 has a tube shape made of a cylinder having substantially the same diameter as the proxy shaft 16, is formed of a synthetic resin material, and is more flexible than the proxy shaft 16. The outer shaft 22 has a proximal end fixed to the distal end of the proximal shaft 16, and a supply / discharge lumen 26 is formed by the central hole of the outer shaft 22 and the central hole of the proximal shaft 16.

The inner shaft 24 has a tube shape made of a synthetic resin material, has a smaller diameter than the outer shaft 22, and is inserted into the distal end portion of the outer shaft 22. Further, the distal end portion of the inner shaft 24 protrudes to the distal end side from the outer shaft 22, and the proximal end of the inner shaft 24 is fixed to the intermediate portion of the outer shaft 22 so as to open to the outer peripheral surface. Yes. Thus, the central hole of the inner shaft 24 is a guide wire lumen 28 having a distal end opened to the tip surface and a proximal end opened to the outer peripheral surface of the intermediate portion of the outer shaft 22. The proximal end portion of the inner shaft 24 is formed as a port 30 that extends at an angle with respect to the axial direction (the left-right direction in FIG. 1) and opens to an intermediate portion of the outer shaft 22.

A cylindrical tip chip 32 made of a relatively hard synthetic resin material is attached to the distal end of the inner shaft 24, and a guide wire lumen 28 opens to the tip surface through the center hole. ing.

Furthermore, a balloon 14 is provided at the distal end portion of the inner shaft 24. The balloon 14 is a cylindrical or bag-like member formed of a thin film of a synthetic resin material, and has a larger diameter than the inner shaft 24 in an expanded state. The balloon 14 has a proximal end fixed to the distal end of the outer shaft 22 by fusion and the like, and the distal end is fused and integrated to the outer peripheral surface of the distal end portion of the inner shaft 24. Is fixed. In addition, as a balloon, in addition to a stenosis part such as a blood vessel as shown in the present embodiment and a stent that expands and deforms by expanding pressure, a cutting blade is provided on the outer peripheral surface to be calcified. A cutting balloon (such as Japanese Patent Laid-Open No. 5-293176) for incising a lesioned part or a spiral wire rod (scoring element) on the outer peripheral surface is provided. Balloons of various structures such as a scoring balloon (Japanese Patent Publication No. 2007-530158) adapted to prevent displacement can be employed.

Thereby, a space separated from the outside is formed between the balloon 14 and the inner shaft 24, and a supply / discharge lumen 26 formed on the outer shaft 22 is communicated with the proximal end of the space. When the fluid is supplied to the balloon 14 from the supply / discharge device (not shown) connected to the connector 20 through the supply / discharge lumen 26, the balloon 14 is inflated, and the fluid in the balloon 14 is discharged to the outside through the supply / discharge lumen 26. As a result, the balloon 14 is deflated. At the proximal end portion and the distal end portion of the balloon 14, a radiopaque annular marker 34 made of a metal material is fitted to the inner shaft 24, and is inserted into a blood vessel to be described later. The position of the balloon 14 can be confirmed by contrast.

In the balloon catheter 10, the proxy shaft 16 and the inner shaft 24 are connected to each other by a connecting wire 36 as a wire. The connecting wire 36 is a solid small-diameter rod-shaped member formed of a metal material such as stainless steel, and its proximal end portion is fixed to the proximal shaft 16 and its distal end portion is an inner shaft. 24 is fixed. The connecting wire 36 has a greater axial rigidity than the distal shaft 18 formed of a synthetic resin material, and deformation such as expansion and contraction is less likely to occur due to the force acting in the axial direction. Yes. The connecting wire 36 may be formed with a substantially constant cross-sectional shape (thickness) from the proximal end to the distal end. More preferably, for example, the connecting wire 36 gradually becomes thinner from the proximal end toward the distal end. It is formed with a taper-shaped wire (with a small cross-sectional area). The connecting wire 36 is preferably formed of a metal material in order to obtain a sufficient strength with a small diameter, but may be formed of a hard synthetic resin material or the like.

The connecting wire 36 protrudes in a substantially axial direction from the distal end of the proximal shaft 16 by the proximal end portion being superimposed on the inner peripheral surface of the proximal shaft 16 and fixed by means such as welding. It is arranged. In the present embodiment, the entire proxy shaft 16 is formed of a metal material, and an arbitrary portion of the proxy shaft 16 to which the connecting wire 36 is fixed is a proximal fixing portion.

The inner shaft 24 is provided with a fixing ring 38 as a distal fixing portion. The fixing ring 38 is an annular member formed of a metal material such as stainless steel. In this embodiment, the fixing ring 38 is substantially the same as the annular marker 34 formed of a radiopaque material. ing. The fixing ring 38 is inserted and fixed to the insertion portion of the inner shaft 24 into the outer shaft 22. The fixing ring 38 may be fixed to the inner shaft 24 by means such as adhesion or welding in addition to fitting.

And the part which protruded from the distal end of the proxy shaft 16 in the connection wire 36 is overlapped on the outer peripheral surface of the fixing ring 38 and fixed by means such as welding, so that the connection wire 36 is attached to the inner shaft 24. On the other hand, it is fixed via a fixing ring 38. The fixing ring 38 is attached to the distal end side of the port 30 of the inner shaft 24, and the connecting wire 36 is disposed across the port 30 in a state where the proxy shaft 16 and the inner shaft 24 are connected. Yes.

Furthermore, the portion of the connecting wire 36 that protrudes from the distal end of the proxy shaft 16 is disposed so as to be relatively displaceable without being fixed to the outer shaft 22. Thereby, transmission of force between the outer shaft 22 and the connecting wire 36 is prevented. In the present embodiment, the connecting wire 36 has a smaller diameter than the gap in the direction perpendicular to the axis of the outer shaft 22 and the inner shaft 24, and in a stationary state in which the shaft 12 is not deformed by the input of external force, the connecting wire 36 is spaced apart from the outer shaft 22 in the direction perpendicular to the axis.

The balloon catheter 10 having such a structure is used for, for example, percutaneous coronary intervention (PCI). That is, the guide wire 40 previously inserted into the blood vessel is inserted through the guide wire lumen 28 and the balloon catheter 10 is pushed along the guide wire 40, whereby the balloon 14 is inserted into the stenosis portion of the blood vessel. Thereafter, the balloon 14 is inflated by supplying a fluid to the balloon 14 through the supply / discharge lumen 26, and the stenosis portion is expanded by the inflation pressure of the balloon 14. In addition, the stent is inserted into the stenosis part by inserting the stent into the deflated balloon 14 and inserting the stent into the stenosis part, and expanding and deforming the stent while expanding the stenosis part by expanding the balloon 14. Can also be used for surgery.

Thus, when the balloon catheter 10 is pushed forward and the balloon 14 is inserted into the stenosis, the pushing force exerted on the connector 20 operated by the practitioner (acting toward the distal end side) The force that pushes the distal end side) is transmitted efficiently toward the distal end side of the distal shaft 18 via the proxy shaft 16.

That is, the connecting wire 36 fixed to the proximal shaft 16 and protruding from the distal end is fixed to the inner shaft 24, so that the pushing force exerted on the connector 20 by the practitioner causes the proximal shaft 16 to And extends from the proxy shaft 16 to the inner shaft 24 via the connecting wire 36. Thereby, the pushing force exerted by the practitioner is efficiently transmitted to the tip 32 provided at the distal end of the inner shaft 24, and the balloon catheter 10 having excellent pushability that allows easy passage through the stenosis is realized. Is done.

In addition, the formation portion of the port 30 where strength reduction is likely to be a problem in the distal shaft 18 is reinforced by the connecting wire material 36, thereby preventing the occurrence of bending (kinks) due to exerting a pushing force, The pushing force is effectively transmitted to the distal end.

Further, the connecting wire 36 formed of a metal material is firmly fixed to the proxy shaft 16 formed of a metal material by welding. Therefore, the connecting wire 36 is prevented from coming off the proxy shaft 16 by the action of the pushing force, and the pushing force is effectively transmitted to the distal end side.

Furthermore, a fixing ring 38 made of a metal material is fitted and fixed to the inner shaft 24, and a connecting wire 36 made of a metal material is firmly fixed to the fixing ring 38 by welding. This prevents the connection wire 36 and the inner shaft 24 from being released by the action of the pushing force, and the pushing force is effectively transmitted to the distal end side.

Moreover, since the distal fixing portion for fixing the connecting wire 36 is an annular fixing ring 38, a sufficiently large fixing force for the inner shaft 24 can be obtained, and the position of the fixing ring 38 with respect to the inner shaft 24 can be obtained. Since displacement is also prevented, transmission of the pushing force to the inner shaft 24 via the connecting wire 36 is effectively realized.

In particular, since the fixing ring 38 of the present embodiment is the same as the annular marker 34, there is no need to newly prepare a special part as the fixing ring. Facilitation can be achieved.

Further, since the connecting wire 36 of the present embodiment has a tapered shape that gradually becomes smaller in diameter toward the distal end side, it is caused by the action of the pushing force at the welded portion with respect to the proximal shaft 16 and the fixing ring 38. The connecting wire 36 is more effectively prevented from coming out to the distal end side. As a result, the pushing force is stably transmitted to the distal end side of the inner shaft 24, and insertion through the narrowed portion becomes easy.

In the balloon catheter 10, it has been confirmed through experiments that the position where the connecting wire 36 is fixed to the inner shaft 24 does not greatly affect the transmission efficiency of the pushing force with respect to the distal end of the inner shaft 24 (see FIG. 5). ). In this experiment, the balloon catheter 10 is inserted into a pseudo blood vessel filled with water, and the distal end (tip tip 32) of the balloon catheter 10 is pressed against a measurement portion of a push gauge (pressing load measuring instrument) to The maximum load value when the catheter 10 was pushed 10 mm toward the distal end at a speed of 5 mm per second was measured. In the balloon catheter 10 used in this experiment, the distance from the tip of the connecting wire 36 to the opening of the port 30 is 60 mm.

That is, as shown in FIG. 5, when fixed to the fixing ring 38 at a position 10 mm from the tip of the connecting wire 36 and when fixed to the fixing ring 38 at a position 25 mm from the tip of the connecting wire 36. And the maximum value of the load is substantially the same when the welding wire is fixed to the fixing ring 38 at a position 40 mm from the tip of the connecting wire 36. In addition, even when welding and fixing to the fixing ring 38 at two positions of 10 mm and 40 mm from the tip of the connecting wire 36, the maximum load value is greatly changed as compared with the case of fixing at one position. There was no.

As is clear from this, in the balloon catheter 10 of the present embodiment, the fixing position of the connecting wire 36 in the axial direction with respect to the inner shaft 24 is not particularly limited, and may be fixed at an arbitrary position. Excellent pushability can be obtained effectively. In addition, “Free” in FIG. 5 indicates a case where the connecting wire 36 and the fixing ring 38 are arranged without being fixed by welding.

As mentioned above, although embodiment of this invention has been explained in full detail, this invention is not limited by the specific description. For example, the material for forming the wire is not limited to a metal material such as stainless steel, and a synthetic resin material or the like may be employed. Moreover, the shape (especially cross-sectional shape) of a wire is not limited, For example, wire materials, such as a rectangular cross section and a deformed cross section, are also employable.

Also, two or more wire rods may be provided, and the shaft reinforcing effect can be obtained more effectively. In that case, all the wires may be fixed to the inner shaft at the same position in the axial direction, or may be fixed to the inner shaft at different positions.

Further, in the above-described embodiment, as a method for fixing the wire to the inner shaft 24, a method of welding and fixing the wire to the fixing ring 38 fitted to the inner shaft 24 is exemplified. It is not limited. For example, the wire may be directly superimposed on the outer peripheral surface of the inner shaft 24 and welded and fixed, or may be bonded and fixed using an adhesive.

Furthermore, the wire may be fixed to the proximal shaft 16 or the inner shaft 24 at two or more locations in the axial direction, thereby realizing stronger fixation.

Further, the distal-side fixing portion does not need to be configured by a ring-shaped member such as the fixing ring 38, and may be, for example, a curved plate shape that is overlapped and welded to a part of the inner shaft 24. good. Furthermore, the proximal side fixing | fixed part may be provided, for example by forming only the distal end part of the proximal shaft 16 with a metal material. Further, the distal-side fixing portion and the proximal-side fixing portion are not limited to those formed of a metal material, and those formed of a synthetic resin may be employed.

Further, the shaft 12 does not need to be formed only by the proxy shaft 16 and the distal shaft 18 and may be formed by combining three or more shafts. More specifically, a port shaft including a port 30 may be provided between the proxy shaft and the distal shaft. Further, the proxy shaft and the distal shaft do not necessarily have the same central axis, and the central axes may be shifted in the direction perpendicular to the axis. In this case, for example, the port shaft connecting the proxy shaft and the distal shaft extends while being inclined with respect to the axial direction, so that the continuous supply / discharge lumen 26 is secured.

In the above-described embodiment, one supply / discharge lumen 26 is provided, and both the inflation and deflation of the balloon 14 are executed by the supply / discharge lumen 26. It is also possible to provide independent inflation and deflation lumens.

10: balloon catheter, 12: shaft, 14: balloon, 16: proximal shaft, 18: distal shaft, 22: outer shaft, 24: inner shaft, 26: supply / discharge lumen, 28: guide wire lumen, 36: connection Wire rod (wire rod), 38: fixing ring (distal anchoring portion)

Claims (4)

A proximal end portion of the shaft is constituted by a proximal shaft, and a distal end portion of the shaft is constituted by a distal shaft, and the distal shaft includes an outer shaft and a guide wire having a supply / discharge lumen. A balloon catheter including a lumen at a distal end portion of the inner shaft and communicating with the supply and discharge lumen of the outer shaft.
A wire projecting from the distal end of the proximal shaft is provided, and the wire is fixed to the proximal shaft,
A protruding portion of the wire from the proxy shaft is fixed to the inner shaft of the distal shaft, and the wire is disposed so as to be relatively displaceable with respect to the outer shaft. catheter. The wire is made of a metal material, and a distal fixing portion made of a metal material is provided on the inner shaft of the distal shaft, and the wire is fixed to the distal fixing portion. The balloon catheter according to claim 1. The balloon catheter according to claim 2, wherein the distal adhering portion is a fixing ring fitted to the inner shaft. The wire rod is formed of a metal material, and the proximal shaft is provided with a proximal fixing portion formed of a metal material, and the wire rod is fixed to the proximal fixing portion. 4. The balloon catheter according to any one of items 1 to 3.

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