JP6430136B2 - Balloon catheter and balloon catheter manufacturing method - Google Patents

Description

  The present invention relates to a balloon catheter having a balloon that can be transitioned between a folded state and an expanded state, and a method for manufacturing the same.

  A balloon catheter is widely used as a medical instrument for expanding blood vessel stenosis and improving blood flow on the peripheral side of a blood vessel when stenosis occurs in a blood vessel such as a blood vessel. Expansion of the stenosis site by the balloon includes a case where the balloon is expanded so that the balloon directly contacts the stenosis site and a case where the balloon is expanded from the inside of the stent (when the stent is placed in the stenosis site). When performing a procedure using a balloon catheter, first, the balloon catheter is inserted into the blood vessel so that the balloon matches the stenotic site. Next, the stenotic site is expanded by injecting a pressurized fluid into the balloon to expand the balloon. After performing dilatation treatment, the balloon is deflated and the balloon catheter is removed from the blood vessel.

  Here, after the balloon portion is folded and reduced in diameter, the balloon portion is passed through a narrow vessel and then expanded in a target stenosis site or a stent. The dilated balloon is deflated for removal from within the vessel or movement to the next treatment site within the vessel.

  For this reason, the balloon is required to return to its original folded shape after expansion. As one method for realizing such performance, Patent Document 1 discloses a technique of forming a balloon at a high temperature using a mold. Patent Document 2 discloses a technique for forming a balloon itself into a special shape.

JP 2003-62080 A Japanese Patent No. 26711961

  By the way, the balloon of the conventional balloon catheter has insufficient shape restoration performance after expansion, and once the balloon is pressurized and expanded, it is difficult to return to the original folded shape even if the balloon is decompressed and contracted. For this reason, once the balloon is expanded, even if it is depressurized and contracted, it becomes larger than the contour before expansion, so when it is removed from the vessel or moved to the next treatment site in the vessel Sometimes, the inner vessel wall can be damaged. In addition, since the balloon with a large outline becomes easily caught at the stenosis site, in order to reach the balloon to the next treatment site (stenosis site), the balloon of the stenosis site should not be damaged by the balloon. Carefully push the balloon catheter to the stenosis site. Also, if it is difficult to position the balloon after deflation at the next treatment site (stenosis site) because it is too large, replace it with a new balloon catheter with a balloon that has never been expanded. There is a need. As a result, the treatment time becomes longer, and there is a possibility that it becomes a burden on the patient's body.

  Further, as described in Patent Document 1, if the balloon is shaped at a high temperature, even if the shape restoration performance is improved, the flexibility of the balloon is reduced by heating, and the strength of the balloon may be reduced depending on the heating temperature. Therefore, the performance required for the balloon catheter itself may be impaired.

  The present invention has been made in consideration of the above points, and provides a balloon catheter having sufficient flexibility and strength for performing treatment and having good shape restoration performance. The present invention also provides a method for manufacturing such a balloon catheter.

One aspect of the balloon catheter of the present invention is:
A tubular shaft,
A balloon provided at a distal portion of the shaft and capable of transitioning in a folded state and an expanded state by fluid flowing in and out through the lumen of the shaft;
A balloon catheter having
The balloon is then closed and the shape memory layer glass transition temperature of below body temperature, and a high strength base layer than prior Symbol shape memory layer,
The shape memory layer is formed on both the inside and the outside of the base material layer .

One aspect of the method for producing a balloon catheter of the present invention includes:
A step glass transition temperature to create a balloon with a high substrate layer strength than the shape memory layer and the shape memory layer is below body temperature, both the shape memory layer of the inner and outer side of the base layer Forming the step,
Attaching the balloon to a tubular shaft formed with a lumen for allowing fluid to flow into and out of the balloon;
Folding the balloon at a temperature higher than the glass transition temperature of the shape memory layer, and making the balloon memorize the folded shape by lowering the glass transition temperature in this folded state;
including.

  According to the present invention, it is possible to realize a balloon catheter that has sufficient flexibility and strength to perform treatment and has good shape restoration performance.

Schematic which shows the whole structure of the balloon catheter which concerns on embodiment Cross-sectional view of a balloon according to an embodiment Sectional view of a balloon according to another embodiment

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

<Overall configuration>
FIG. 1 is a diagram showing a configuration example of a balloon catheter according to an embodiment of the present invention. The balloon catheter 100 includes a hub 110, a balloon 120, a proxy shaft 130, a distal shaft 140, and a guide wire lumen tube 150.

  The hub 110 is placed at the hand of a doctor who operates the balloon catheter 100 in angioplasty. The hub 110 is configured to be connectable to a pressure application device (not shown) such as an inflator that supplies a high-pressure fluid. The proximal shaft 130 is joined to the hub 110 so as to be in fluid communication, and extends distally. Further, a distal shaft 140 is joined to the distal side so as to be in fluid communication. A balloon 120 is joined to the distal side of the distal shaft 140. The proxy shaft 130 and the distal shaft 140 have a tube shape, and a flow path for supplying a high-pressure fluid into the balloon 120 is formed. The distal end of the balloon 120 surrounds the outer peripheral surface of the guide wire lumen tube 150 and is joined to the outer peripheral surface.

  The guide wire lumen tube 150 penetrates the distal shaft 140 so that the inner shaft (guide wire lumen) forms a coaxial or biaxial double tube structure with the distal shaft 140 without communicating with the flow path. It is provided through the balloon 120. The opening on the proximal side of the guide wire lumen tube 150 is disposed in the vicinity of the joint between the proxy shaft 130 and the distal shaft 140, and the opening on the distal side of the guide wire lumen tube 150 is the tip of the balloon 120. It is arranged further to the distal side than the part. The proximal opening is provided as a guide wire port 170 that is an insertion / extraction port for the guide wire 160.

  With this configuration, the high-pressure fluid supplied to the balloon 120 stays inside the balloon 120 and the balloon 120 expands. Before the high-pressure fluid is supplied to the inside, the balloon 120 is folded so as to have substantially the same size as the outer diameter of the distal shaft 140, and is provided so as to be in close contact with the outer peripheral surface on the distal side of the guide wire lumen tube 150. Yes. When the high-pressure fluid is supplied to the inside of the balloon 120, the balloon 120 expands by expanding the fold. FIG. 1 shows a state where the balloon 120 is expanded.

<Configuration of balloon 120>
FIG. 2 is a cross-sectional view in which a portion of the balloon 120 of the present embodiment is cut in a direction perpendicular to the longitudinal direction of the shaft 140. FIG. 2 shows a state where the balloon 120 is expanded or a state before shaping.

  The balloon 120 has a shape memory layer 121 and a base material layer 122. The shape memory layer 121 is fixed to the inner surface of the base material layer 122.

  The shape memory layer 121 is made of a material having a glass transition temperature equal to or lower than the body temperature. The body temperature can be approximately 33 ° C. to 42 ° C., and the average body temperature is approximately 37 ° C. Considering that it is difficult to assume that the body temperature of a person who performs treatment using the balloon catheter 120 is 33 ° C. or lower, a material having a glass transition temperature of 33 ° C. or lower is selected as the shape memory layer 121. Yes. Thus, as the shape memory layer 121, it is preferable to use a material having a glass transition temperature equal to or lower than the lowest body temperature assumed during treatment.

  Furthermore, considering the ease of realizing the environmental temperature when storing the shape (shaping) and the restoring force when exceeding the glass transition temperature, the glass transition temperature of the shape memory layer 121 is too low. Better not. In practice, the glass transition temperature Tg of the shape memory layer 121 is preferably in the range of 0 ° C. ≦ Tg ≦ 33 ° C. In the present embodiment, polyurethane having a glass transition temperature of 30 ° C. is used as the shape memory layer 121.

  The base material layer 122 is formed of a material having higher strength than the shape memory layer 121. Actually, the strength here is the tensile strength. Thereby, even when fluid is injected into the balloon 120 and the pressure in the balloon 120 becomes high, it is possible to prevent the balloon 120 from rupturing or having a hole in the balloon 120 to leak fluid from the inside to the outside.

  As the material of the base material layer 122, it is preferable to use a highly flexible material in addition to the strength higher than that of the shape memory layer 121 as described above. As such a material, for example, polyamide or polyamide elastomer is used. Can be used.

  The balloon 120 is not limited to FIG. 2 and may be configured as shown in FIG. That is, the shape memory layer 121 may be disposed on the outer peripheral surface side of the base material layer 122 as shown in FIG. 3A, and the base material is disposed on the outer peripheral surface side and the inner peripheral surface side of the shape memory layer 121 as shown in FIG. The layer 122 may be formed, and the shape memory layer 121 may be formed on the outer peripheral surface side and the inner peripheral surface side of the base material layer 122 as shown in FIG. 3C. Further, the shape memory layer 121 is not necessarily formed over the entire circumference of the balloon 120, and may be partially fixed in the circumferential direction of the base material layer 122. In short, the balloon 120 only needs to have a shape memory layer having a glass transition temperature equal to or lower than the body temperature and a base material layer having higher strength than the shape memory layer.

<Production method of balloon catheter>
Next, a method for manufacturing a balloon catheter according to the present embodiment will be described.

  First, a tube having a shape memory layer and a base material layer is prepared by an extrusion molding machine. The tube may be formed by coating the base material layer with a shape memory layer, in addition to forming the tube by an extrusion molding machine. The present invention is not limited to the method of forming the shape memory layer and the base material layer.

  Next, the proximal end of this tube is joined to the outer peripheral surface of the distal shaft 140, and the distal end is joined to the outer peripheral surface of the guide wire lumen tube 150. It is attached to the vicinity of the distal end of the distal shaft 140 in a state in which fluid can be introduced into the tube through the lumen of 140 and can be expanded.

  After attaching the tube to the outer peripheral surfaces of the distal shaft 140 and the guide wire lumen tube 150 in this manner, the tube is expanded by placing the tube in the inner space of the cylindrical outer frame (die), thereby removing the tube. Press contact with the inner surface of the frame. In this state, the temperature of the tube is made higher than the glass transition temperature of the shape memory layer, and then made equal to or lower than the glass transition temperature of the shape memory layer. Thereby, the balloon 120 as shown in FIG. 2 or FIG. 3 is formed.

  Next, a folded shape is attached to the balloon 120 (that is, the folded shape is stored). This shaping may be performed, for example, by reducing the diameter of the outer frame (die) covering the balloon 120 while rotating the balloon 120. Thereby, the balloon 120 can be folded like an umbrella. At the time of shaping, the temperature of the balloon 120 is made higher than the glass transition temperature of the shape memory layer 121 and then made the glass transition temperature of the shape memory layer 121 or lower. In this embodiment, since polyurethane having a glass transition temperature of 30 ° C. is used as the shape memory layer 121, the balloon 120 is kept at 30 ° C. in a state where folding pressure is applied to the balloon 120 from the outer peripheral direction by an outer frame (die). After making the temperature higher than that, shaping is performed by setting the temperature to 30 ° C. or lower.

<Operation and Effect of Embodiment>
The balloon 120 shaped and folded by the manufacturing method described above is inserted into a blood vessel such as a blood vessel. At this time, since the temperature in the vessel is higher than the glass transition temperature, the balloon 120 can be smoothly moved to the treatment site while maintaining the folded shape.

  The balloon 120 is expanded by pressurizing the inside of the balloon 120 at the treatment site. At this time, since the balloon 120 has the base material layer 122, even if a pressure equivalent to the conventional pressure (for example, about 20 atmospheres) is applied, the balloon 120 is expanded without causing rupture or leakage.

  Next, in order to remove the balloon 120 from the inside of the vessel or to move to the next treatment site in the vessel, the inside of the balloon 120 is decompressed and the balloon 120 is deflated. At this time, the balloon 120 has the shape memory layer 121 and its glass transition temperature is set to the body temperature or lower, so that the balloon 120 returns to the folded state. As a result, the balloon 120 has a smaller outline in the folded state when it is once deflated and then contracted, so that the balloon 120 can move smoothly in the vessel. In particular, since it becomes difficult to get caught at the next stenosis site (treatment site), the deflated balloon can be smoothly positioned at the next treatment site (stenosis site). As a result, the treatment time is shortened and the burden on the patient is reduced.

  Since the balloon 120 of the present embodiment has the shape memory layer 121 having a glass transition temperature equal to or lower than the body temperature, it is not necessary to shape at a high temperature, so that the flexibility of the base material layer 122 is not reduced. Due to the effect of the shape memory layer 121, the force to return to the original folded shape in the blood vessel (blood vessel) having a temperature equal to or higher than the glass transition temperature is large. Incidentally, since the balloon 120 according to the present embodiment never falls below the glass transition temperature in the body, the expanded state is not stored, and the folded state remains stored. In addition, a material having a low glass transition temperature generally has low strength, but in this embodiment, the strength is compensated by providing the base material layer 122.

  As described above, according to the present embodiment, the balloon 120 of the balloon catheter 100 includes the shape memory layer 121 having a glass transition temperature equal to or lower than the body temperature, and the base material layer 122 having higher strength than the shape memory layer 121. With this configuration, it is possible to realize a balloon catheter having sufficient flexibility and strength for performing treatment and good shape restoration performance.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

  The present invention can be applied to a balloon catheter having a balloon that can transition between a folded state and an expanded state.

DESCRIPTION OF SYMBOLS 100 Balloon catheter 110 Hub 120 Balloon 121 Shape memory layer 122 Base material layer 130 Proximal shaft 140 Distal shaft 150 Guide wire lumen tube 160 Guide wire 170 Guide wire port

Claims (5)

A tubular shaft,
A balloon provided at a distal portion of the shaft and capable of transitioning in a folded state and an expanded state by fluid flowing in and out through the lumen of the shaft;
A balloon catheter having
The balloon is then closed and the shape memory layer glass transition temperature of below body temperature, and a high strength base layer than prior Symbol shape memory layer,
The shape memory layer is formed on both the inside and outside of the base material layer,
Balloon catheter. The glass transition temperature of the shape memory layer is 33 ° C. or lower.
The balloon catheter according to claim 1. The shape memory layer includes polyurethane.
The balloon catheter according to claim 1 or 2. A method for manufacturing a balloon catheter, comprising:
A step glass transition temperature to create a balloon with a high substrate layer strength than the shape memory layer and the shape memory layer is below body temperature, both the shape memory layer of the inner and outer side of the base layer Forming the step,
Attaching the balloon to a tubular shaft formed with a lumen for allowing fluid to flow into and out of the balloon;
Folding the balloon at a temperature higher than the glass transition temperature of the shape memory layer, and making the balloon memorize the folded shape by lowering the glass transition temperature in this folded state;
A method for manufacturing a balloon catheter. The glass transition temperature of the shape memory layer is 33 ° C. or lower.
The manufacturing method of the balloon catheter of Claim 4.

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