JP6742885B2 - Balloon catheter - Google Patents

Description

The present invention relates to a balloon catheter having an in-vivo expandable balloon.

In recent years, a balloon catheter has been used to improve a lesion (stenosis) generated in a living body lumen. The balloon catheter usually includes a long shaft portion and a balloon that is provided on the distal end side of the shaft portion and is expandable in the radial direction. The deflated balloon can be expanded by reaching the target location in the body through the thin living body lumen and then expanding the balloon.

By the way, there is a high possibility that the shape of the balloon after the expansion will be disturbed during the contraction and will not return to the shape before the expansion. If the shape of the balloon is disturbed, the outer diameter of the balloon increases, and it may be difficult to draw the balloon into the sheath or guiding catheter. Therefore, Patent Document 1 describes a balloon in which the flexibility of a part of the balloon is increased and the rigidity of a part of the balloon is further increased so that the balloon can be easily contracted to a desired shape after being expanded. This balloon is easily folded into a desired shape by forming a trough in a region with increased flexibility and a crest in a region with enhanced rigidity.

International Publication No. 2008/060750

Even with the balloon described in Patent Document 1, for example, when the balloon is long in the axial direction, the shape is likely to differ depending on the axial position of the balloon, and it is difficult to reliably deflate the balloon to a small size.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a balloon catheter that can be reliably contracted to a small size after the balloon is expanded, and that can be easily recovered after use.

A balloon catheter that achieves the above-mentioned object is provided with a long shaft portion and an outer peripheral surface of a distal portion of the shaft portion that is folded, and a balloon that is expandable when a fluid flows into the interior thereof. At least one ring-shaped contraction assisting portion that has a higher elasticity than the balloon and surrounds a part of the outer peripheral surface of the balloon in the axial direction in the circumferential direction. The portion is slidable with respect to the balloon, and in a state in which the balloon is expanded, the contraction assisting portion extends longer than a natural length to generate a contracting force, and the contraction assisting portion is is fixed to a part of the circumferential direction of the outer peripheral surface of the balloon, in the folded state the balloon, the deflated auxiliary section, it is extended longer than the natural length.

In the balloon catheter configured as described above, the expansion assist portion expands when the balloon expands, so the expansion of the balloon is not hindered by the expansion assist portion. When the balloon is expanded, a contraction force is generated in the contraction assisting portion, so that when the fluid is discharged from the balloon, the contraction assisting portion contracts. As a result, the balloon can be reliably deflated by the deflation assisting section, and the balloon after use can be easily collected.

The contraction assisting portion may be fixed to a part of the outer peripheral surface of the balloon in the circumferential direction. As a result, it is possible to prevent the contraction assisting part from falling off the balloon. Further, when the balloon expands and contracts, the part of the contraction assisting part that is not fixed to the balloon slides on the balloon and can expand and contract favorably.

A plurality of the contraction assisting portions may be provided on the outer peripheral surface of the balloon along the axial direction. Accordingly, the entire axial direction of the balloon can be effectively deflated by the deflation assisting portion. Therefore, for example, even when the balloon is long in the axial direction, the entire axial direction of the balloon can be effectively deflated.

In the folded state of the balloon, the contraction assisting portion may extend longer than its natural length. As a result, it is possible to prevent the contraction assisting portion from loosening on the outer peripheral surface of the folded balloon. Therefore, it is possible to suppress the contraction assisting part from being caught by another part, and it is possible to suppress the contraction assisting part from falling off from the balloon during transportation. Further, since the contraction force of the contraction assisting portion acts on the balloon, it is possible to maintain the balloon before expansion with a small diameter and to contract the balloon after once expanded to a small diameter.

It is a top view showing the balloon catheter concerning this embodiment. It is sectional drawing which shows the distal part of the balloon catheter in the state where the balloon was deflated. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which shows the distal part of the balloon catheter in the state where the balloon was expanded. It is sectional drawing which follows the BB line of FIG. It is a top view which shows the distal part of the balloon catheter which the balloon deflated after expansion.

An embodiment of the present invention will be described below with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated and different from the actual ratios for convenience of description.

The balloon catheter 10 according to the present embodiment is a device that is used by percutaneously inserting into a living body lumen and is used to push out a narrowed portion of the living body lumen. The balloon catheter 10 is a so-called rapid exchange type catheter, and as shown in FIGS. 1 to 3, a long shaft portion 20, a balloon 30 provided at a distal end portion of the shaft portion 20, and a shaft. It has a hub 40 fixed to the base end of the portion 20, a tip 50 located at the extreme end of the shaft portion 20, and a contraction assisting portion 60 attached to the balloon 30. In the present specification, the side of the balloon catheter 10 that is to be inserted into the body lumen is referred to as the “tip side”, and the side on which the balloon catheter 10 is operated is referred to as the “proximal side”.

The shaft portion 20 has a tubular proximal shaft 21 having a proximal end fixed to the hub 40, a tubular intermediate shaft 22 covering the distal end side of the proximal shaft 21, and a tubular distal end provided on the distal end side of the intermediate shaft 22. The shaft 23 and a tubular inner tube 24 arranged inside the distal shaft 23 are provided. Inside the proximal shaft 21, the intermediate shaft 22, and the distal shaft 23, an expansion lumen 25 through which an expansion fluid for expanding the balloon 30 flows is formed.

The inner tube 24 coaxially penetrates the inside of the tip shaft 23 and the balloon 30. The distal end portion of the inner tube 24 extends in the distal direction from the distal end of the balloon 30, and is joined to the distal end side of the balloon 30 while maintaining liquid tightness. A tubular tip 50 is fixed to the tip of the inner tube 24. The tip 50 is a flexible member that reduces the burden on the living tissue that abuts in the living body. The base end of the inner pipe 24 is fixed to a part (side opening formed on the side surface) in the outer peripheral direction of the intermediate shaft 22 while maintaining liquid tightness. The proximal end opening of the inner tube 24 is exposed to the outside of the intermediate shaft 22 and constitutes the proximal end side opening portion 27 of the guide wire lumen 26. An internal space from the distal end side opening 51 formed in the distal end tip 50 to the proximal end side opening 27 serves as a guide wire lumen 26. The guide wire is inserted into the inner tube 24 with the distal end side opening 51 as an inlet and the proximal end side opening 27 as an outlet. The base end side opening 27 may be provided not on the intermediate shaft 22 but on the base end shaft 21 or the tip shaft 23, or at the boundary (joint portion) between the intermediate shaft 22 and the tip shaft 23. Good.

The hub 40 includes a hub opening 41 that communicates with the expansion lumen 25 of the shaft portion 20 and functions as a port for allowing the expansion fluid to flow in and out.

The balloon 30 is a part that expands and expands the narrowed portion. The outer surface of the balloon 30 may be coated with a drug for suppressing stenosis. Alternatively, on the outer surface of the balloon 30, a stent that is plastically deformed by the expansion of the balloon 30 and placed in the stenosis may be placed. The distal end side of the balloon 30 is joined to the outer wall surface of the inner tube 24 while maintaining liquid tightness. The proximal end side of the balloon 30 is joined to the outer wall surface of the distal end portion of the distal shaft 23 while maintaining liquid tightness. Therefore, the inside of the balloon 30 communicates with the expansion lumen 25 formed in the shaft portion 20, and the expansion fluid can flow from the proximal end side through the expansion lumen 25. The balloon 30 is expanded by the inflow of the expansion fluid and is contracted by discharging the inflowing expansion fluid.

The balloon 30 has a plurality of protrusions 31 that protrude outward in the radial direction by, for example, blow molding. The balloon 30 having the protruding portion 31 can be formed by, for example, blow molding in which a tube serving as a material is heated in a mold, and pressurized from the inside so as to be expanded by a fluid and pressed against the mold. The method for molding the balloon 30 is not particularly limited. The number of the protrusions 31 is four in this embodiment, but may be one or more and can be set appropriately. In addition, the balloon 30 may not include the protrusion as long as it can be folded. The protrusions 31 are preferably provided at equal intervals in the circumferential direction of the balloon 30, but may not be provided at equal intervals. In the deflated state before use, the protruding portion 31 of the balloon 30 is folded around the outer peripheral surface of the inner tube 24 so as to be wound in the circumferential direction.

The constituent material of the balloon 30 is preferably formed of a material having a certain degree of flexibility, and examples of such a material include polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer. Polymers, ionomers, or polyolefins such as a mixture of two or more thereof, soft polyvinyl chloride resins, polyamides, polyamide elastomers, polyesters, polyester elastomers, polyurethanes, thermoplastic resins such as fluororesins, silicone rubbers, latex rubbers, etc. Can be used.

The contraction assisting portion 60 is a ring-shaped member that surrounds the outer peripheral surface of the balloon 30 in the folded state. At least a part of the deflation assisting section 60 is slidable with respect to the outer peripheral surface of the balloon 30 without being folded together with the balloon 30. The contraction assisting section 60 has a higher elasticity than the balloon 30. Therefore, when the balloon 30 is expanded and contracted, the contraction assisting portion 60 can be expanded by expanding the material itself and contracted to its original shape. Two contraction assisting parts 60 are provided at intervals in the axial direction of the balloon 30. The contraction assisting portion 60 may be one, or three or more. Each contraction assisting portion 60 is fixed to the outer peripheral surface of the balloon 30 at one or more positions in the circumferential direction. The contraction assisting portion 60 and the fixing portion 61 of the balloon 30 are formed by, for example, heat fusion or adhesion. The fixing portion 61 is provided on the outer peripheral surface of the balloon 30 in the folded state, which is exposed to the outside. The fixing portions 61 to which the respective contraction assisting portions 60 are fixed are provided, for example, one for each of the folded protruding portions 31. It should be noted that the fixing portions 61 to which the respective contraction assisting portions 60 are fixed may not be provided one by one on each of the protruding portions 31.

The peripheral length of the inner peripheral surface of the contraction assisting portion 60 in the natural state before being attached to the balloon 30 is smaller than the peripheral length of the balloon 30 in the folded state. As a result, the contraction assisting portion 60 is arranged on the outer peripheral surface of the folded balloon 30, so that the contraction assisting portion 60 is stretched to some extent, and the contracting force of the contraction assisting portion 60 acts on the balloon 30. Therefore, the contraction assisting portion 60 is arranged on the outer peripheral surface of the balloon 30 without sagging. Further, since the contracting force acts on the balloon 30, the balloon 30 can be maintained with a small diameter. The peripheral length of the inner peripheral surface of the contraction assisting portion 60 in the natural state before being attached to the balloon 30 may be equal to or slightly larger than the peripheral length of the balloon 30 in the folded state. In this case, the deflation assisting portion 60 is arranged on the outer peripheral surface of the balloon 30 to restrict the contracting force of the deflation assisting portion 60 from continuing to act on the folded balloon 30, and to keep the shape of the balloon 30 until it is used. And the state can be maintained appropriately.

The constituent material of the contraction assisting portion 60 is preferably a material having higher elasticity than the balloon 30, and is, for example, an elastic material. As the constituent material of the shrinkage assisting portion 60, for example, natural rubber such as latex, silicone rubber, urethane rubber, ethylene-propylene-diene rubber, nitrile rubber, fluorine rubber, synthetic rubber such as acrylic rubber and the like can be used.

Next, the operation of the balloon catheter 10 according to this embodiment will be described.

In the state before use of the balloon catheter 10, as shown in FIGS. 1 to 3, a ring-shaped contraction assisting portion 60 is provided on the outer peripheral surface of the folded balloon 30. The contraction assisting portion 60 extends longer than its natural length, is stretched to some extent, and is disposed on the outer peripheral surface of the balloon 30. Therefore, it is possible to prevent the contraction assisting portion 60 from being loosened on the outer peripheral surface of the balloon 30 and being caught by another portion, and to prevent the contraction assisting portion 60 from falling off from the balloon 30 during transportation. Further, since the contraction force of the contraction assisting portion 60 acts on the balloon 30, the balloon 30 can be maintained with a small diameter. Therefore, the balloon 30 can be properly inserted into the thin living body lumen. Further, since the contraction assisting portion 60 is fixed to the balloon 30 by the fixing portion 61 provided on a part of the outer peripheral surface of the balloon 30 in the circumferential direction, the contraction assisting portion 60 is prevented from falling off in the living body. When the balloon 30 expands and contracts, the part of the contraction assisting part 60 that is not fixed to the balloon 30 can be expanded and contracted satisfactorily.

After arranging the balloon 30 at a target position such as a stenosis in a living body lumen and supplying a fluid from the hub opening 41 to the inside of the balloon 30 through the dilation lumen 25, as shown in FIGS. The folded protrusion 31 expands and the balloon 30 expands. When the balloon 30 expands, the contraction assisting portion 60 surrounding the outer peripheral surface of the balloon 30 expands and expands together with the balloon 30. When the folded portion of the balloon 30 is opened, the balloon 30 is greatly expanded while exerting a strong pressing force on the contact target. On the other hand, the contraction assisting portion 60 stretches and expands the material without hindering the expansion of the balloon 30. Since the contraction assisting portion 60 is expandable, the expansion of the balloon 30 is not hindered by the contraction assisting portion 60. At this time, by providing the fixing portion 61 on each of the protruding portions 31 arranged in the circumferential direction, when the balloon 30 is expanded, the entire contraction assisting portion 60 in the circumferential direction can be expanded substantially uniformly. Therefore, the contraction force of the contraction assisting portion 60 acting on each protrusion 31 of the balloon 30 is also substantially uniform, and the balloon 30 can be appropriately expanded. Further, since the contraction assisting portion 60 is partially provided in a part of the outer peripheral surface of the balloon 30 in the axial direction, the balloon 30 can be brought into contact with the inner surface of the living tissue. Therefore, for example, when the outer surface of the balloon 30 is coated with a drug, the drug can be brought into contact with the biological tissue to act without being blocked by the contraction assisting portion 60.

When the fluid is discharged from the inside of the balloon 30 through the expansion lumen 25 and the hub opening 41, the balloon 30 contracts as shown in FIG. 6. At this time, since the protrusions 31 arranged in the circumferential direction are provided with the fixing portions 61, when the balloon 30 is deflated, the deflation assisting portion 60 allows the entire deflation of the balloon 30 to be substantially evenly deflated. it can. When the balloon 30 is deflated, it can be deflated small if it is in a folded state before expansion. However, it is usually difficult for the balloon 30 to return to the folded state before expansion, its shape is not stable, and it is difficult to make it deflate small. In particular, when the length of the balloon 30 in the axial direction is long, the balloon 30 is deformed into different shapes depending on the position in the axial direction, so that the shape is not stable and it is difficult to shrink the balloon small. However, since the balloon catheter 10 according to the present embodiment is provided with the ring-shaped contraction assisting portion 60 surrounding the outer peripheral surface of the balloon 30, when the fluid is discharged from the inside of the balloon 30, the contraction force of the contraction assisting portion 60 is increased. Acts on the balloon 30, and the balloon 30 contracts to a small extent. Furthermore, since the plurality of deflation assisting portions 60 are provided in the axial direction of the outer peripheral surface of the balloon 30, even if the balloon 30 is long in the axial direction, the deflation assisting portion 60 can reliably deflate the entire axial direction. .. This makes it easy to pull the used balloon 30 into the sheath 70 (or guiding catheter) and collect it inside the living body lumen.

The present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, the balloon catheter 10 described above is a rapid exchange type, but may be an over-the-wire type.

10 Balloon Catheter 20 Shaft Part 30 Balloon 31 Projection Part 60 Contraction Assist Part 61 Fixed Part

Claims (2)

With a long shaft part,
A balloon that is provided by being folded on the outer peripheral surface of the distal portion of the shaft portion and is expandable by the fluid flowing into the inside,
Surrounding a part of the outer peripheral surface of the folded balloon in the axial direction in the circumferential direction, and having at least one ring-shaped contraction assisting portion having higher elasticity than the balloon,
At least a part of the contraction assisting portion in the circumferential direction is slidable with respect to the balloon,
In the state where the balloon is inflated, the contraction assisting portion extends longer than its natural length to generate a contracting force ,
The contraction assisting part is fixed to a part of the outer peripheral surface of the balloon in the circumferential direction,
In a folded state the balloon, the deflated auxiliary section, the balloon catheter that has been extended longer than the natural length. The shrinkage auxiliary section, the balloon catheter of claim 1 which is more provided along the axial direction on the outer peripheral surface of the balloon.

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