JP2006015064A - Balloon catheter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balloon catheter capable of treating lesion tissue by heating and cooling an organism organ in an extremely short time, having high heat exchanging efficiency with uniform temperature distribution in a balloon, allowing the use of the balloon formed of thermoplastic resin and capable of safely expanding without damaging a blood vessel. <P>SOLUTION: This balloon catheter has a proximal part connecting component having a liquid inflow port, a liquid outflow port and an optical fiber lead-in port; a catheter shaft having a liquid inflow lumen, a liquid outflow lumen and an optical fiber; and a heating member and the balloon. The proximal part connecting component and a catheter shaft proximal part are connected, and a catheter shaft distal part and a balloon proximal part are connected. The heating member exists in the balloon or in the catheter shaft distal part. The heating member is formed of a metal member, and the tip part of the optical fiber is shaped to be gradually reduced in diameter toward the tip in the heating member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a balloon catheter for treating a biological tubular organ. More specifically, the present invention can treat a diseased tissue by heating and cooling a living organ within a very short time, and has a uniform temperature distribution in the balloon, high heat exchange efficiency, and a balloon made of a thermoplastic resin. The present invention relates to a balloon catheter that can be used, and particularly adapted to percutaneous coronary angioplasty and the like, and can be safely expanded without damaging a blood vessel.

Balloon-based percutaneous coronary angioplasty (PTCA) has shown remarkable spread in recent years. Initially, the number of cases and lesions that can be indicated were limited, but due to the development of devices and advances in technology, indications have been extended not only to multibranch lesions but also to complete occlusion and acute myocardial infarction. However, the frequency of occurrence of restenosis after surgery is quite large, which is regarded as the biggest problem of PTCA. Various types of stents have been developed and used to prevent restenosis, but the effect of preventing restenosis is small. When restenosis occurs, the placed stent may interfere with the treatment. is there. Furthermore, there are cases where stainless steel, which is the material of the stent, shows an allergic reaction to the tissue. Therefore, it is desirable to treat stenosis and prevent restenosis without using foreign matter such as stainless steel. In the past, laser treatments that directly burn or evaporate luminal tissue with a laser, or methods that treat stenotic sites with an argon laser, etc. have been tried. It appears and fails because it has no effect.
In luminal tissue restenosis, when smooth muscle cells are damaged, when the tissue is repaired by stem cells, disrupted abnormal information is transmitted, or abnormal differentiation of stem cells occurs, which is considered to be restenosis. ing. In addition, the blood vessel to be treated is cut by a so-called TEC (transluminal extraction catheter) or rotablator, and the stent is placed only in the outer membrane, but when necessary tissue is excised. Even if an endothelial tissue is formed, this is not stabilized, and it is considered that restenosis eventually occurs. In normal PTCA, in order to forcibly dilate blood vessels at a high pressure of 800 to 1,000 kPa, excessive smooth muscles are damaged during the repair process from coronary artery damage by tearing the tissue or altering the vascular tissue with great force. Cell proliferation occurs and restenosis is likely to occur.
For this reason, attempts have been made to develop instruments and methods for expanding blood vessels without damaging the blood vessels in the stenosis. For example, a device useful for the application of heat in a patient's body, useful for procedures such as angioplasty, is to simultaneously heat and pressurize the luminal tissue, to improve the yielding behavior or thermal conductivity of the luminal tissue. A body lumen expansion system has been proposed that has a catheter control means that detects changes and responds to tissue behavior (Patent Document 1). However, it is extremely difficult to uniformly determine the physiological response of affected areas with different lesion states and to perform optimal treatment on each affected area. In PTCA, as a catheter that can thermally coagulate the inner surface of a blood vessel and prevent re-occlusion without causing damage to the intima, a fluorine fiber provided with a laser fiber that enters the inside of the balloon and a laser light absorption heating tube A catheter having a balloon made of a resin is proposed (Patent Document 2). However, when the blood vessel wall is heated to 80 to 90 ° C., the blood vessel wall tends to become thin. Furthermore, as a catheter without local overheating in the balloon, a catheter provided with a metal braided tube and a resin tube covering the tube in the balloon and a catheter provided with two thermocouples has been proposed (Patent Document 3). ). However, this catheter has a problem that it is difficult to obtain a stable and favorable result when an excessive force is applied to the blood vessel or an excessive thermal invasion is applied.
Conventional balloons tend to emit laser light in one direction from the tip of an optical fiber and have low heat exchange efficiency. Moreover, since the balloon is easily heated locally, it was necessary to use a balloon made of a thermosetting resin having good heat resistance. However, compared to balloons made of thermoplastic resin, balloons made of thermosetting resin are less productive and thermosetting, making it difficult to mold without thermal deformation, folding, rewrapability, insertion into body cavities There was a problem that the property was inferior.
Japanese Patent No. 2984056 (page 2) Japanese Patent No. 2535250 (page 1-2) Japanese Patent No. 2864094 (page 1-2)

  The present invention is capable of treating a diseased tissue by heating and cooling a living organ within a very short time, and using a balloon made of a thermoplastic resin with a uniform temperature distribution in the balloon and high heat exchange efficiency. In particular, the present invention is intended to provide a balloon catheter that can be adapted for percutaneous coronary angioplasty and the like and can be safely expanded without damaging a blood vessel.

As a result of intensive studies to solve the above problems, the present inventors have used a balloon equipped with a means for heating in a short time and a means for cooling in a short time, so that the blood vessel can be formed without damage. A heat generating member made of a metal member and an optical fiber whose diameter is reduced toward the tip in the heat generating member are provided in the balloon or the distal portion of the catheter shaft, and laser light is emitted from the optical fiber to the heat generating member. As a result, the balloon is not heated locally, so that the temperature distribution in the balloon becomes uniform and the use of a balloon made of a thermoplastic resin becomes possible, and the present invention is completed based on this finding. It came.
That is, the present invention
(1) Proximal part having a liquid inlet, a liquid outlet, and an optical fiber inlet, a catheter shaft including a liquid inflow lumen, a liquid outflow lumen, and an optical fiber, a heat generating member, and a balloon, Connecting part and catheter shaft proximal portion, catheter shaft distal portion and balloon proximal portion are coupled, and a heat generating member exists in the balloon or in the catheter shaft distal portion, and the heat generating member is a metal member A balloon catheter, characterized in that the tip of the optical fiber has a shape that gradually decreases in diameter toward the tip in the heat generating member,
(2) The balloon catheter according to (1), wherein the tip of the optical fiber has a substantially conical shape, and
(3) The balloon catheter according to (1), wherein the tip of the optical fiber has a substantially hemispherical shape or a substantially semi-spheroid shape,
Is to provide.

  According to the balloon catheter of the present invention, since there is no local heating of the balloon and the temperature distribution becomes uniform, a balloon made of a thermoplastic resin with good operability can be used, and the living organ is heated and cooled within a short time. Thus, the diseased tissue can be treated, and in particular applied to percutaneous coronary angioplasty (PTCA) or the like, and can be safely expanded without damaging the blood vessel to prevent restenosis.

The balloon catheter of the present invention has a proximal connecting part including a liquid inlet, a liquid outlet, and an optical fiber inlet, a catheter shaft including a liquid inlet lumen, a liquid outlet lumen, and an optical fiber, a heating member, and a balloon. A balloon catheter in which the proximal portion connecting part and the catheter shaft proximal portion, the catheter shaft distal portion and the balloon proximal portion are coupled, and the heat generating member exists in the balloon or the catheter shaft distal portion; The balloon catheter has a shape in which the member is made of a metal member, and the distal end portion of the optical fiber gradually decreases in diameter toward the distal end in the heat generating member.
FIG. 1 is an explanatory view of one embodiment of the balloon catheter of the present invention. The balloon according to this aspect includes a proximal connecting component 1 having a liquid inlet, a liquid outlet, and an optical fiber inlet, a lumen 2 for inflowing liquid into the balloon, a lumen 3 for outflowing liquid from the balloon, and an optical fiber for guiding laser light. 4 and a temperature sensor lead wire 5 are inserted through a catheter shaft 6, a heating member 7 and a balloon 8. A liquid feeding device 9 and a laser output device 10 are provided on the hand side, and a temperature sensor 11 is provided in the balloon.

2 is an enlarged view of the balloon portion of the balloon catheter of FIG. 1 and a side view of the distal end portion of the optical fiber. The heat generating member 7 is an assembly in which metal wires are combined in a cylindrical shape, and the distal end portion 12 of the optical fiber has a substantially conical shape in which the diameter gradually decreases toward the front end in the heat generating member. FIG. 3 is an enlarged view of a balloon portion and a side view of the distal end portion of an optical fiber according to another embodiment of the balloon catheter of the present invention. In the balloon of this aspect, the tip portion 13 of the optical fiber has a substantially semi-spheroid shape that gradually decreases in diameter toward the tip in the heat generating member. FIG. 4 is an enlarged view of a balloon portion and a side view of a distal end portion of an optical fiber in an example of a conventional balloon catheter. In the balloon of this example, the distal end portion 14 of the optical fiber is polished after being cut.
In the balloon catheter of the present invention, it is preferable that the entire catheter shaft or the distal portion that is likely to become high temperature is made of a heat resistant material. Examples of the heat-resistant material include NiTi superelastic alloy, stainless steel, polyimide, polyetherimide, polysulfone, polyetheretherketone, and composite materials composed of these. Since these materials have moderate flexibility as well as heat resistance, a well-balanced catheter shaft can be obtained. By constituting at least the distal portion of the catheter shaft with a heat-resistant material, the catheter shaft can be safely used without being damaged by overheating.

In the present invention, the heat generating member is formed of a metal member, and the form thereof is not particularly limited. For example, a metal wire braid exposed by removing the polymer from the metal wire braided polymer tube used as the catheter shaft is used as a metal wire. Can be used as a heat generating member made of a combination of cylinders. In addition to a metal wire coil, a braid, a sputtering film, a dotted deposit, or the like may be used. A combination of metal wires in a cylindrical shape or a coil of metal wires can be used as an X-ray marker. The heating member is an assembly of metal wires combined in a cylindrical shape or a coil of metal wire, and by installing an optical fiber that gradually decreases in diameter toward the tip in the heating member, the laser energy is uniform with respect to the heating member The heat exchange efficiency is improved and the temperature distribution in the balloon becomes uniform. In the conventional balloon catheter, the tip of the optical fiber is polished, but since it has a cut shape, it is emitted only in the front in a bundle shape, so the heat exchange efficiency is low, and the balloon is easily heated locally. For this reason, it was necessary to use a thermosetting resin with high heat resistance as a material of the balloon.
In the balloon catheter of the present invention, the temperature distribution in the balloon becomes uniform and there is no fear that the balloon is locally heated. Therefore, a thermoplastic resin can be used as the material of the balloon. As a thermoplastic resin, not only a thermoplastic resin having no cross-linked structure but also a resin having a partially cross-linked structure should be used as a thermoplastic resin as long as extrusion molding and blow molding are possible. Can do. Examples of the thermoplastic resin used in the present invention include polyolefin resin, polyamide resin, polyamide elastomer, polyetheramide resin, polyester resin, polyester elastomer, fluororesin, polyurethane resin, silicone resin, natural rubber, synthetic rubber and the like. Can do.

In the present invention, the method for producing a balloon made of a thermoplastic resin is not particularly limited. For example, a tube obtained by extrusion molding of a thermoplastic resin is cut into a parison, and the parison is formed by biaxial stretch blow molding. Further, the balloon may be made excellent in heat resistance by dipping a blow molded balloon with a thermosetting resin. Although there is no restriction | limiting in particular in the draw ratio of biaxial stretch blow molding, it is preferable that a length direction is 1.5-5 times and a radial direction is 2-5 times, a length direction is 2-4 times, radial direction. Is more preferably 2.5 to 4 times.
In the present invention, the blow molding temperature of the balloon is preferably 100 ° C. or higher, but may be formed by dipping after blow molding, post-annealing or the like even if it is not 100 ° C. or higher. As the heating medium for the balloon, physiological saline using water as a solvent or dispersion medium, an X-ray contrast medium, etc. are used in most cases, so that the balloon hardly reaches a temperature exceeding 100 ° C. Therefore, by performing balloon blow molding at a temperature of 100 ° C. or higher, when using this balloon catheter, the balloon is hardly deformed by heating and can be used safely. A so-called cold blown balloon at a temperature of about 40 to 80 ° C. has a large strength relative to the thickness because the polymer is oriented and crystallized, but when the temperature is raised above the blow-molded temperature, the shape returns. The balloon diameter tends to be small. In the present invention, since the living organ is expanded without applying high pressure to the balloon, the balloon is not required to have high pressure resistance, and heat stability obtained by blow molding at a high temperature that normally does not give strength. A good balloon can be used.

In the balloon catheter of the present invention, the heat generating member is present in the balloon or in the distal portion of the catheter shaft, and heat is transferred from the heat generating member to the liquid in the flow field. Can be raised. Further, the balloon temperature can be accurately controlled by controlling the amount of energy introduced by sending the signal detected by the temperature sensor to the energy output device. Furthermore, since the heat generating member is present in the balloon, by stopping the introduction of energy, a low temperature liquid is immediately perfused into the balloon, and the balloon temperature can be lowered in a short time. If the heat generating member is located near the proximal portion of the catheter shaft, heat energy is lost from the heated liquid due to conduction to blood, body fluid, tissue, etc., not only lowering thermal efficiency but also unstable temperature control of the balloon It becomes. In the balloon catheter of the present invention, the heating member is present in the balloon or in the distal portion of the catheter shaft, and the liquid is heated in the balloon, so that the balloon temperature can be controlled stably and accurately.
The living body is composed of a protein mainly composed of collagen, and the protein softens when the temperature is increased, like a general polymer. The influence of heat on living cells is moderate in time, and cells are necrotized when kept at a high temperature for a long time. However, changes in physical properties such as collagen in vascular tissue are physicochemical phenomena and occur instantaneously. Therefore, rapidly heating a living tissue in a short time, heating only the very shallow phase of the living tissue without causing biological damage to the deep phase, killing the tissue, or giving an apoptotic factor Can do. In addition, blood vessels that have become physicochemically flexible are expanded at a relatively low pressure, ensuring a lumen for obtaining sufficient blood flow without damaging the tissue due to excessive force. With sufficient blood flow, a stable patency of the lumen can be achieved.

There is no particular limitation on the form of the balloon catheter of the present invention, for example, it can be a monorail type having a guide wire lumen between a balloon distal portion and a guide wire port opened in the middle of the catheter shaft, or An over-the-wire type in which the guide wire lumen penetrates the entire length of the catheter shaft can also be used.
The balloon catheter of the present invention preferably has pressure detection means, and can adjust the degree of opening and closing of the liquid inlet and the liquid outlet or the inlet pressure, and pressurize the balloon to inflate it. While introducing the balloon into the stenosis part of the living organ and controlling the pressure using pressure detection means so as not to apply excessive pressure, the balloon is inflated to expand the stenosis part, tearing the tissue, Treatment can be performed without altering the vascular tissue with great force.
In the treatment using the balloon catheter of the present invention, the temperature of the lesioned part of the living organ is preferably raised from 35 to 40 ° C. within 60 seconds and more preferably within 15 seconds. Further, after expanding the balloon by applying a pressure of 500 kPa or less, the balloon is preferably cooled to a temperature of 45 ° C. or less within 40 seconds, more preferably within 20 seconds. There is no particular limitation on the order of temperature increase of the lesioned part of the living organ and expansion by pressurizing the balloon. For example, the temperature can be increased after pressurizing the balloon to 500 kPa or less. In this case, at a temperature near room temperature, expansion does not occur even when a pressure of 500 kPa or less is applied to the balloon. However, when the temperature reaches 60 to 80 ° C., the living organ expands.

There is no restriction | limiting in particular in the liquid used for the balloon catheter of this invention, For example, a physiological saline, an X-ray contrast agent, these liquid mixture, these dilution liquids etc. can be mentioned.
The balloon catheter of the present invention can be particularly suitably applied to the treatment of vascular lesions such as percutaneous coronary angioplasty (PTCA). When the smooth muscle cells are damaged, when the tissue is repaired by the stem cells, abnormal information that is destroyed is transmitted, or abnormal differentiation of the stem cells occurs, thereby causing restenosis. Is believed to occur. In addition, the treated blood vessel is cut by a so-called TEC or rotablator, and the stent is placed only in the outer membrane. However, if the necessary tissue is excised, the endothelial tissue is temporarily removed. Even if possible, this is not stabilized, and it is thought that restenosis will eventually occur. As a method of treating living organs with heat. Like hyperthermia, the expansion of organs and esophagus, cancer treatment, etc., heat is applied to a deep part of the living body as long as possible to raise the temperature and kill the tissue. . On the other hand, according to the balloon catheter of the present invention, only the surface of the vascular tissue is instantaneously heated, and the luminal tissue is expanded at a low pressure without damaging the deep portion of the luminal tissue. Without damaging the vascular tissue by force, the vascular tissue can be treated safely and effectively, and a good therapeutic effect can be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1:
A balloon catheter provided with three temperature sensors shown in FIG. 5 was used. The catheter shaft is a SUS braided polyamide tube with an overall length of 1,400 mm, an outer diameter of 1 mm, and a wall thickness of 50 μm. Inside, there are two lumens with an outer diameter of 0.45 mm and a wall thickness of 30 μm for perfusion of contrast medium / saline. A 100 μm quartz optical fiber and a temperature sensor lead were inserted.
The balloon is made of polyamide, and has an outer diameter of 3 mm at the time of expansion, a length of 15 mm at a portion having an outer diameter of 3 mm at the time of expansion excluding the neck, and a film thickness of 20 μm. The SUS braided polyamide tube in the balloon was removed by a length of 15 mm to expose the SUS braided to obtain a laser energy conversion element. A 15 mm tip of the quartz optical fiber was processed into a conical shape and aligned in accordance with the laser energy conversion element. In addition, temperature sensors 15, 11 and 16 were attached at three locations on the distal end side, the center and the proximal end side of the balloon.
The balloon was immersed in a constant temperature bath at a water temperature of 37 ° C., and a contrast medium / saline 1/1 diluted solution was continuously press-fitted with a contrast medium injection pump so that the balloon internal pressure became 200 kPa. Introduce 5W YAG laser energy into the optical fiber, raise the temperature in 20 seconds until the central temperature sensor reaches 70 ° C, feed back the central temperature sensor signal, and maintain 70 ° C for 10 seconds by turning on / off the laser energy After that, the laser energy was turned off and cooled to 45 ° C. or lower in 20 seconds.
This operation was repeated 10 times every 5 minutes, and the temperature indicated by the temperature sensor on the distal end side and the temperature sensor on the proximal end side of the balloon was recorded. There was almost no difference between the temperature indicated by the temperature sensor on the distal end side and the temperature indicated by the temperature sensor on the proximal end side.
Example 2
The tip of the quartz optical fiber is processed into a half of a spheroid having a major axis length of 240 μm and a minor axis length of 100 μm shown in FIG. The same operation as in Example 1 was performed by positioning at a position 2 mm away from the proximal end to the distal end side.
In ten measurements, there was almost no difference between the temperature indicated by the temperature sensor on the distal end side and the temperature indicated by the temperature sensor on the proximal end side.
Comparative Example 1
The tip of the quartz optical fiber was used as the cut surface shown in FIG. 4, and the cut surface was aligned at a location 2 mm away from the proximal end to the distal end side of the heat generating member, and the same operation as in Example 1 was performed.
In 10 measurements, there is a temperature difference between the temperature indicated by the temperature sensor on the distal end side and the temperature indicated by the temperature sensor on the proximal end side. Differences as high as 10 ° C were observed.

  According to the balloon catheter of the present invention, since the temperature distribution of the balloon becomes uniform, it is possible to use a balloon made of a thermoplastic resin with good operability. It can be treated and applied in particular to percutaneous coronary angioplasty (PTCA) and the like to safely dilate without damaging blood vessels and prevent restenosis.

It is explanatory drawing of the one aspect | mode of the balloon catheter of this invention. It is an enlarged view of the balloon part of FIG. 1, and the side view of the front-end | tip part of an optical fiber. It is the enlarged view of the balloon part of the other aspect of the balloon catheter of this invention, and the side view of the front-end | tip part of an optical fiber. It is the enlarged view of the balloon part of an example of the conventional balloon catheter, and the side view of the front-end | tip part of an optical fiber. It is the enlarged view of the balloon part of the balloon catheter used in the Example, and the side view of the front-end | tip part of an optical fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Proximal part connection component 2 Lumen for liquid inflow 3 Lumen for liquid outflow 4 Optical fiber 5 Temperature sensor conducting wire 6 Catheter shaft 7 Heating member 8 Balloon 9 Liquid feeder 10 Laser output device 11 Temperature sensor 12 Optical fiber tip 13 Optical fiber tip Part 14 Optical fiber tip 15 Temperature sensor 16 Temperature sensor

Claims (3)

  Proximal part connecting part including liquid inlet, liquid outlet and optical fiber inlet, Proximal part connecting part having liquid inflow lumen, liquid outlet lumen and catheter shaft including optical fiber, heating member and balloon A catheter shaft proximal portion, a catheter shaft distal portion and a balloon proximal portion are combined, and a heat generating member is present in the balloon or in the catheter shaft distal portion, the heat generating member comprising a metal member, A balloon catheter having a shape in which a distal end portion of an optical fiber gradually decreases in diameter toward the distal end in the heat generating member.   The balloon catheter according to claim 1, wherein a tip portion of the optical fiber has a substantially conical shape.   The balloon catheter according to claim 1, wherein the tip of the optical fiber has a substantially hemispherical shape or a substantially semi-spheroid shape.

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