JP6164638B2 - Balloon catheter - Google Patents

Description

  The present invention relates to a rapid exchange type balloon catheter.

Conventionally, a balloon catheter having an outer shaft and an inner shaft is known (see, for example, Patent Document 1 and Patent Document 2).
In the rapid exchange type balloon catheter as shown in Patent Document 1 and Patent Document 2, a balloon is attached to the distal end of the outer shaft, the distal end portion of the inner shaft is fixed to the distal end portion of the balloon, and the proximal end of the inner shaft Open on the side of the outer shaft to form a guide wire port. Here, a fluid for expanding the balloon is circulated through the lumen of the outer shaft (expansion lumen), and a guide wire is inserted through the lumen of the inner shaft (guide wire lumen).

  The balloon catheters as shown in Patent Document 1 and Patent Document 2 are provided on the proximal end side of the first tube to form the first tube for forming the distal end side of the outer shaft and the proximal end side of the outer shaft. It is manufactured by heat-sealing the arranged second tube and the third tube inserted into the first tube to form an inner shaft, whereby the first tube and the second tube A guide wire port is formed therebetween.

JP 2002-28243 A JP 2003-164528 A

(1) However, in the above-described balloon catheter, when the first tube, the second tube, and the third tube are heat-sealed (fusing step), the base end portion of the third tube is configured. There is a problem that a part of the resin melts and flows out to the proximal end side, and as a result, the wall thickness of the inner shaft formed by the third tube is remarkably reduced (thinned).

(2) When the wall thickness of the inner shaft decreases, when the balloon catheter is used (when the balloon is expanded), the inner shaft is crushed by the pressure of the liquid flowing through the expansion lumen, the guide wire lumen is narrowed, and the guide wire stacks. Cause the problem. Such a problem is remarkable in a high pressure type balloon catheter (for example, the maximum expansion pressure (RBP) is 18 atm or more).

(3) The first tube and the second tube for forming the outer shaft are made of a thermoplastic resin such as PEBAX (polyether block amide).
On the other hand, the inner shaft is composed of an outer layer made of a thermoplastic resin such as PEBAX and an inner layer made of a thermoplastic resin having good lubricity, such as polyethylene or fluorine resin.

  Here, the resin (polyethylene or fluorine-based resin) constituting the inner layer of the inner shaft is not thermally fused to the first tube and the second tube made of PEBAX or the like, and therefore melts in the fusion process and is proximal. The constituent resin of the inner layer that has flowed out into the blade extends from the vicinity of the opening of the inner shaft serving as the guide wire port and becomes a blade-like small piece (burr). In order to avoid peeling and entering the blood vessel when using the balloon catheter, it is necessary to remove the small piece (burr) after the fusion process, but the work for removing the small piece (for example, cutting with a razor) ) Is extremely complicated.

The present invention has been made based on the above situation.
A first object of the present invention is to provide a balloon catheter capable of suppressing / preventing a decrease in the wall thickness of an inner shaft during its manufacture (fusion process).
The second object of the present invention is to provide a balloon catheter that can prevent collapse of the inner shaft (constriction of the guide wire lumen) and accompanying guide wire stacking during use (during balloon expansion). There is.
A third object of the present invention is to provide a balloon that does not generate small pieces (burrs) derived from the constituent resin of the inner layer of the inner shaft in the vicinity of the opening of the inner shaft serving as a guide wire port during the production (fusion process). It is to provide a catheter.

(1) The balloon catheter of the present invention includes an outer shaft made of a thermoplastic resin,
A balloon that is attached to the tip of the outer shaft and expands with a liquid flowing through an expansion lumen formed in the outer shaft;
An inner layer made of a thermoplastic resin that cannot be fused to the outer shaft; and an outer layer made of a thermoplastic resin that can be fused to the outer shaft, and is inserted into the outer shaft and the balloon. An inner shaft that forms a guide wire lumen for inserting a guide wire, the distal end of which is fixed to the distal end of the balloon, and the distal end of which opens as a guide wire port;
It is made of a thermoplastic resin that can be fused to the outer layer of the outer shaft and the inner shaft, and is connected to the base end of the inner shaft to form a guide wire lumen together with the inner shaft and directly connected to the outer shaft And the base end is provided with the connection tube of the single layer structure opened in the side surface of the said outer shaft as a guide wire port, It is characterized by the above-mentioned.

(2) In the balloon catheter of the present invention, a first tube for forming the distal end side of the outer shaft;
A second tube disposed on the base end side of the first tube to form a base end side of the outer shaft;
A third tube comprising the inner layer and the outer layer, and inserted into the first tube to form the inner shaft;
In order to form the connection tube, it is preferable that the fourth tube having a single-layer structure disposed on the base end side of the third tube is heat-sealed.

According to the balloon catheter having the above-described configuration, the resin constituting the third tube (inner layer and outer layer) for forming the inner shaft is melted and flows out to the proximal end side during the production (fusion process). The fourth tube for forming the connection tube can be suppressed by closing the flow path, and as a result, the wall thickness of the inner shaft can be maintained.
As a result of maintaining the wall thickness of the inner shaft, when the balloon catheter is used (when the balloon is expanded), the inner shaft is crushed and the guide wire lumen is narrowed by the pressure of the liquid that expands the balloon. And therefore no guide wire stacking occurs.
Further, since the constituent resin of the inner layer of the inner shaft does not flow out to the base end side in the fusion process, the guide wire port that is the opening of the connection tube is used for the blade-like small piece (burr) derived from the constituent resin of the inner layer. It does not occur in the vicinity of

(3) In the balloon catheter of the present invention, the outer shaft (the first tube and the second tube), the outer layer of the inner shaft (the third tube), and the connection tube (the fourth tube) are configured. The thermoplastic resin is at least one selected from polyamide, polyether polyamide, polyurethane, polyether block amide (PEBAX) and nylon, and the thermoplastic resin constituting the inner layer of the inner shaft (the third tube) is Polyolefin or fluorine resin is preferable.

(4) In the balloon catheter of the present invention, the outer shaft (the first tube and the second tube), the outer layer of the inner shaft (the third tube), and the connection tube (the fourth tube) are configured. Preferably, the thermoplastic resin is polyether block amide (PEBAX) or nylon, and the thermoplastic resin constituting the inner layer of the inner shaft (the third tube) is polyethylene.

  When using polyethylene that has a relatively low melting point and is not thermally fused with PEBAX or nylon as the inner layer of the inner shaft (third tube), a connecting tube ( It is particularly effective to connect the fourth tube).

(5) In the balloon catheter of the present invention, it is preferable that the connection tube (fourth tube) is made of a thermoplastic resin having a hardness of 70 or more according to a D-type hardness meter.
By using a high-hardness thermoplastic resin as the constituent material of the connection tube (fourth tube), it is possible to further improve the rigidity as a guide wire shaft (the effect of preventing the narrowing of the guide wire lumen).

According to the balloon catheter of the present invention, it is possible to suppress / prevent a decrease in the wall thickness of the inner shaft at the time of manufacture (fusion process).
Further, when the balloon catheter of the present invention is used (when the balloon is expanded), collapse of the inner shaft (stenosis of the guide wire lumen) and accompanying guide wire stacking can be prevented.
Furthermore, when the balloon catheter of the present invention is manufactured (fusion process), small pieces (burrs) derived from the constituent resin of the inner layer of the inner shaft are not generated in the vicinity of the guide wire port.

It is explanatory drawing which shows the balloon catheter which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional view (part II detail view) showing the main part of the balloon catheter shown in FIG. 1. FIG. 3 is a partially enlarged view (part III detail view) of FIG. 2. It is IV-IV sectional drawing of FIG. It is sectional drawing which shows the manufacturing process (arrangement | positioning of the shaft before melt | fusion) of the balloon catheter shown in FIG. FIG. 6 is a partially enlarged view of FIG. 5 (detailed view of a VI part).

The balloon catheter 100 of this embodiment shown in FIGS. 1 to 4 is used for percutaneous coronary angioplasty (PTCA) or the like.
The balloon catheter 100 includes an outer shaft 10 made of a thermoplastic resin, a balloon 20 that is attached to the distal end of the outer shaft 10 and expands with a liquid flowing through an expansion lumen 10L formed on the outer shaft 10, and the outer shaft 10 And an outer layer 32 made of a thermoplastic resin that can be fused to the outer shaft 10, and is inserted into the outer shaft 10 and the balloon 20. Then, a guide wire lumen 30L for inserting the guide wire is formed (which constitutes a guide wire shaft), the distal end portion thereof is fixed to the distal end portion of the balloon 20, and the inner end is opened as the guide wire port 35. Shaft 30, outer shaft 10 and a It is made of a thermoplastic resin that can be fused to the outer layer 32 of the inner shaft 30 and is connected to the proximal end side of the inner shaft 30 to form a guide wire lumen 30L together with the inner shaft 30 (which constitutes the guide wire shaft). ), And a connection tube 40 whose proximal end opens as a guide wire port 45.
In FIG. 1, 50 is a hypotube connected to the base end side of the outer shaft 10, 60 is a hub attached to the base end side of the hypotube 50, and 70 is a strain relief. 2 to 4, reference numeral 80 denotes a core wire inserted into the expansion lumen 10 </ b> L formed on the outer shaft 10.

An expansion lumen 10L that circulates a fluid for expanding the balloon 20 is formed on the outer shaft 10 constituting the balloon catheter 100.
The outer diameter of the outer shaft 10 is preferably 0.7 to 1.0 mm, and 0.85 mm as a suitable example.
The length of the outer shaft 10 is preferably 150 to 450 mm, and is 390 mm if a suitable example is shown.

Examples of the constituent material of the outer shaft 10 include thermoplastic resins such as polyamide, polyether polyamide, polyurethane, polyether block amide (PEBAX) (registered trademark), and nylon. Of these, PEBAX is preferable.
The hardness of the outer shaft 10 is preferably 63 to 80 as measured by a D-type hardness meter.

A balloon 20 is attached to the tip of the outer shaft 10.
The balloon 20 is expanded by the liquid flowing through the expansion lumen 10L of the outer shaft 10. Here, examples of the liquid include physiological saline.
The diameter of the balloon 20 at the time of expansion is preferably 1.0 to 5.0 mm.
The length of the balloon 20 is preferably 5 to 40 mm.

  As the constituent material of the balloon 20, the same balloon as that of a conventionally known balloon catheter can be used, and PEBAX can be cited as a suitable material. The strength of the constituent material of the balloon 20 is preferably a flexural modulus of 680 Mpa to 780 Mpa. If the strength is too low, it tends to over-expand and tends to cause wrinkles.

An inner shaft 30 is inserted into the outer shaft 10 and the balloon 20, and the inner shaft 30 forms a guide wire lumen 30 </ b> L for inserting a guide wire as a guide wire shaft.
The distal end portion of the inner shaft 30 is fixed to the distal end portion of the balloon 20, and an opening as a guide wire port 35 is formed at the distal end of the inner shaft 30.
On the other hand, as shown in FIG. 3, the base end portion of the inner shaft 30 is fixed (heat-sealed) to the outer shaft 10 with the outer periphery covered with the constituent resin of the outer shaft 10.

  The inner shaft 30 includes an inner layer 31 made of a thermoplastic resin that cannot be fused to the outer shaft 10 and an outer layer 32 made of a thermoplastic resin that can be fused to the outer shaft 10.

The outer diameter of the inner shaft 30 is preferably 0.48 to 0.60 mm. The inner shaft 30 preferably has an inner diameter of 0.35 to 0.45 mm.
The thickness of the inner layer 31 is preferably 0.005 to 0.030 mm.
The thickness of the outer layer 32 is preferably 0.01 to 0.10 mm.

The constituent material of the inner layer 31 is preferably a resin having a low coefficient of friction and good lubricity, and specific examples include polyolefins such as polyethylene, fluorine resins such as PFA, PTFE, and the like. Of these, polyethylene is preferred.
As a constituent material of the outer layer 32, the thermoplastic resin illustrated as what comprises the outer shaft 10 can be mentioned, Among these, PEBAX is preferable.
The hardness of the inner shaft 30 (outer layer 32) is preferably 55 or more as measured by a D-type hardness meter from the viewpoint of ensuring the rigidity as a guide wire shaft.

As shown in FIG. 3, the connection tube 40 is connected and fixed (heat-sealed) to the proximal end side of the inner shaft 30.
The connection tube 40 forms a guide wire lumen 30 </ b> L together with the inner shaft 30. That is, in the balloon catheter 100 of the present embodiment, a guide wire shaft is constituted by the inner shaft 30 and the connection tube 40, and an opening as a guide wire port 45 is formed at the proximal end of the connection tube 40.

The outer diameter and inner diameter of the connection tube 40 are approximately the same as the outer diameter and inner diameter of the inner shaft 30, respectively.
The length (L40) of the connection tube 40 is preferably 1 to 5 mm.
When this length (L40) is too short, the object of the present invention cannot be sufficiently achieved. On the other hand, when this length (L40) is too long, the lubricity of the guide wire lumen 30L may be impaired.

The connection tube 40 is a single-layer tube made of a thermoplastic resin that can be fused to the outer layer 32 of the outer shaft 10 and the inner shaft 30.
Examples of the constituent material of the connection tube 40 include the thermoplastic resins exemplified as those constituting the outer shaft 10, and among them, PEBAX and nylon are preferable.
The hardness of the connection tube 40 is preferably 70 or more, particularly 72 or more as measured by a D-type hardness meter, from the viewpoint of ensuring the rigidity as a guide wire shaft.

The metal hypotube 50 constituting the balloon catheter 100 of the present embodiment has its distal end inserted into the proximal end of the outer shaft 10 and its proximal end inserted into the strain relief 70 and the hub 60.
The hypotube 50 may be made of stainless steel, Ni—Ti, Cu—Mn—Al alloy, or the like, and a spiral slit may be formed at a tip portion thereof.
The length of the hypotube 50 is normally 900 to 1500 mm.

An opening (balloon expansion port 65) for introducing a fluid for expanding the balloon 20 is formed at the proximal end portion of the hub 60 attached to the hypotube 50.
An inflator is attached to the hub 60, and the pressure for expanding the balloon is adjusted by the inflator.

The recommended expansion pressure (NP) of the balloon catheter 100 of the present embodiment is preferably 8 atm or more, more preferably 10 to 14 atm.
The maximum expansion pressure (RBP) is preferably 18 atm or more, and more preferably 20 to 25 atm.
In such a high pressure resistant specification, the balloon catheter of the present invention is effective.

The balloon catheter 100 of this embodiment can be manufactured by heat-sealing a tube for forming a shaft constituting the balloon catheter 100.
Specifically, as shown in FIGS. 5 and 6, a first tube 10A for forming the distal end side of the outer shaft 10, a second tube 10B for forming the proximal end side of the outer shaft 10, A third tube 30A for forming the inner shaft 30 and a fourth tube 40A for forming the connection tube 40 are arranged, and a mandrel 90 (guide wire) is disposed in the lumen of the third tube 30A and the lumen of the fourth tube 40A. A mandrel (not shown) for securing an expansion lumen is inserted through the lumen of the first tube 10A and the lumen of the second tube 10B .

As shown in FIG. 6, the first tube 10 </ b> A and the second tube 10 </ b> B are fitted by inserting the tube wall of the latter distal end portion into the slit formed in the tube wall of the former proximal end portion. . Further, the third tube 30A arranged outside the second tube 10B is inserted into the first tube 10A. A fourth tube 40A is arranged on the proximal end side of the third tube 30A.

The first tube 10A, the second tube 10B , the third tube 30A, and the fourth tube 40A arranged in this manner are covered with a shrink tube, and heated and pressurized via the shrink tube, so that these tubes are heated to each other. It is fused and fixed. Thereafter, the mandrel 90 for securing the guide wire lumen and the mandrel for securing the expansion lumen are removed, whereby a balloon catheter having a structural portion as shown in FIGS. 2 to 4 can be obtained.

In the above fusion process, the first tube 10A and the second tube 10B for forming the outer shaft 10 and the third tube 30A for forming the inner shaft 30 are reliably heat-sealed. 6, the region M surrounded by the dotted line is intensively heated. As a result, the thermoplastic resin located in the region, particularly the thermoplastic resin constituting the proximal end portion of the third tube 30A (the constituent resin of the inner layer 31A). And the constituent resin of the outer layer 32A) are completely melted.

On the other hand, most of the fourth tube 40A disposed on the proximal end side of the third tube 30A is located at a certain distance in the proximal direction from the region M that is intensively heated. The thermoplastic resin constituting the tip portion of the fourth tube 40A is slightly melted and thermally fused with the first tube 10A, the second tube 10B, and the third tube 30A, but the heat constituting the fourth tube 40A. Most of the plastic resin does not flow out to the base end side, but is connected and fixed (heat-sealed) on the base end side of the third tube 30A.

  Thereby, even if the thermoplastic resin constituting the base end portion of the third tube 30A melts and flows out to the base end side in the fusion process, the flow is blocked by the fourth tube 40A. As a result, the reduction (thinning) of the wall thickness of the inner shaft caused by the flow of the resin constituting the third tube 30A is suppressed, and the inner shaft 30 can maintain the intended wall thickness. .

Further, in the fusion process, the inner layer 31A of the third tube 30A that comes into contact with the outer peripheral surface of the mandrel 90 is covered with the outer layer 32A of the third tube 30A and the fourth tube 40A that are thermally fused together. The constituent resin of the inner layer 31A of the third tube 30A cannot flow out to the proximal end side.
Thereby, a blade-like small piece (burr) derived from the constituent resin of the inner layer 32A is not formed in the vicinity of the opening (guide wire port 45) of the connection tube 40 formed by the fourth tube 40A. . Therefore, it is not necessary to remove these small pieces (burrs), which is extremely advantageous from the viewpoint of manufacturing efficiency.

According to the balloon catheter 100 of the present embodiment, the reduction (thinning) of the wall thickness of the inner shaft caused by the constituent resin of the third tube 30A flowing out to the proximal end, which was a problem in the conventional balloon catheter, is caused. As a result, the inner shaft 30 can maintain the desired wall thickness.
As a result of maintaining the rigidity of the shaft by maintaining the wall thickness of the inner shaft 30, there is a problem with the conventional balloon catheter when the balloon catheter 100 of the present embodiment is used (when the balloon 20 is expanded). The pressure of the liquid that expands the balloon does not collapse the inner shaft and constrict the guidewire lumen, and therefore does not cause a guidewire stack.
Further, a blade-like small piece (burr), which is a problem in the conventional balloon catheter, is not generated in the vicinity of the guide wire port 45 that is the opening of the connection tube 40 formed by the fourth tube 40A.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to these, A various change is possible.
For example, the outer layer of the inner shaft and the connection tube may be formed from a plurality of layers.

DESCRIPTION OF SYMBOLS 100 Balloon catheter 10 Outer shaft 10L Expansion lumen 20 Balloon 30 Inner shaft 30L Guide wire lumen 31 Inner layer 32 Outer layer 35 Guide wire port 40 Connection tube 45 Guide wire port 50 Hypo tube 60 Hub 65 Balloon expansion port 70 Strain relief 80 Core wire 90 Mandrel 10A 1st tube
10B 2nd tube 30A 3rd tube 31A Inner layer 32A Outer layer 40A 4th tube

Claims (5)

An outer shaft made of thermoplastic resin;
A balloon that is attached to the tip of the outer shaft and expands with a liquid flowing through an expansion lumen formed in the outer shaft;
An inner layer made of a thermoplastic resin that cannot be fused to the outer shaft; and an outer layer made of a thermoplastic resin that can be fused to the outer shaft, and is inserted into the outer shaft and the balloon. An inner shaft that forms a guide wire lumen for inserting a guide wire, the distal end of which is fixed to the distal end of the balloon, and the distal end of which opens as a guide wire port;
It is made of a thermoplastic resin that can be fused to the outer layer of the outer shaft and the inner shaft, and is connected to the base end of the inner shaft to form a guide wire lumen together with the inner shaft and directly connected to the outer shaft A balloon catheter characterized in that a proximal end of the balloon catheter includes a single-layer connection tube that opens as a guide wire port on a side surface of the outer shaft . A first tube for forming a distal end side of the outer shaft;
A second tube disposed on the base end side of the first tube to form a base end side of the outer shaft;
A third tube comprising the inner layer and the outer layer, and inserted into the first tube to form the inner shaft;
2. The balloon catheter according to claim 1, wherein a fourth tube having a single-layer structure disposed on a proximal end side of the third tube is heat-sealed to form the connection tube. The outer shaft, the outer layer of the inner shaft, and the thermoplastic resin constituting the connection tube are at least one selected from polyamide, polyether polyamide, polyurethane, polyether block amide, and nylon,
The balloon catheter according to claim 1 or 2, wherein the thermoplastic resin constituting the inner layer of the inner shaft is a polyolefin or a fluorine resin. The outer shaft, the outer layer of the inner shaft, and the thermoplastic resin constituting the connection tube is polyether block amide or nylon,
The balloon catheter according to claim 1 or 2, wherein the thermoplastic resin constituting the inner layer of the inner shaft is polyethylene.   The balloon catheter according to any one of claims 1 to 4, wherein the connection tube is made of a thermoplastic resin having a hardness measured by a D-type hardness meter of 70 or more.

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