JP2005058509A - Ablation catheter with balloon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a catheter from being elongated by an operation during use. <P>SOLUTION: In the ablation catheter of this invention, since a string 16 for elongation prevention pulls an outer cylinder shaft 3 from the vicinity of a tip to the hand side at all times, the heat-softened outer cylinder shaft 3 is prevented from being elongated in the length direction. Since the vicinity of the tip of an inner cylinder shaft 4 is also indirectly connected to the string 16 for the elongation prevention through a balloon 2 and the string 16 for the elongation prevention pulls the inner cylinder shaft 4 as well from the vicinity of the tip to the hand side at all times, the inner cylinder shaft 4 heat-softened during high-frequency energizing is prevented from being elongated in the length direction. Since high-frequency power for heating does not enter the nonmetallic string 16 for the elongation prevention, the loss of the high-frequency power for heating and the heat generation of the string itself by the entrance of the high-frequency power are avoided. As a result, the catheter 1 is prevented from being elongated by the operation during the use and from obstructing the operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal electrode for high-frequency energization in a balloon and a high-frequency energization arranged as a counter electrode on the patient body surface in a state in which the balloon disposed on the distal end side of the catheter is in close contact with a target lesion site in the patient. The present invention relates to an ablation catheter with a balloon that ablates a target lesion site by heating the target lesion site by performing high-frequency dielectric heating and high-frequency dielectric heating with an external electrode and heating with Joule heat, especially during use. The present invention relates to a technique for preventing the length of the body from extending.

  An ablation catheter with a balloon for pulmonary vein electrical isolation described in JP-A-2002-78809 is an ablation catheter for performing cardiac arrhythmia treatment. When the pulmonary vein is electrically isolated using this ablation catheter with a balloon, as shown in FIG. 6, an inflatable / deflatable balloon 52 disposed on the distal end side of the catheter 51 is percutaneously cut into the inferior vena cava. The balloon 52 is introduced into the QA and pierced through the atrial septum Hw from the right atrium Ha of the heart HA while being pushed by the catheter 51 to reach the left atrium Hb. Then, after the balloon 52, which has been inflated firmly by the supply of the liquid containing the contrast medium into the balloon, is brought into close contact with the pulmonary vein opening Qa, the high frequency power supply is applied to the high frequency energizing inner electrode 53 installed in the balloon 52. High frequency power is applied from 55 and high frequency energization is performed between the high frequency energization outer electrode 54 set on the patient body surface as a counter electrode of the high frequency energization inner electrode 53.

  The annular peripheral edge portion of the pulmonary vein port Qa is entirely heated and cauterized by high-frequency dielectric heating and heating by Joule heat that occur in association with the high-frequency energization between the high-frequency energization inner electrode 53 and the high-frequency energization outer electrode 54. The Following cauterization of the pulmonary vein opening Qa, cauterization of the remaining three pulmonary vein openings Qb to Qd opened on the inner wall of the left atrium Hb is sequentially performed in the same manner. All the four pulmonary veins are electrically isolated by cauterizing the annular peripheral edge of each pulmonary vein opening Qa to Qd. When the annular peripheral edge of each pulmonary vein opening Qa to Qd is cauterized and each of the four pulmonary veins is in the form of electrical isolation, the electrical signal that causes arrhythmia is cut off and the cardiac arrhythmia is almost eliminated.

Thus, according to the ablation catheter with a balloon described in JP-A-2002-78809, the annular peripheral edge of each pulmonary vein opening Qa to Qd is cauterized as a whole, so that the cauterization is not repeated many times. At the same time, only the annular peripheral edge of each pulmonary vein opening Qa to Qd is cauterized, so that it is not necessary to cauterize an extra portion (for example, a healthy part).
Japanese Unexamined Patent Publication No. 2002-78809 (all pages of detailed description, FIGS. 1 to 6)

  However, in the case of the ablation catheter with a balloon described in the above publication, there is a concern that the catheter 51 may be stretched due to an operation in use and hinder the operation of the catheter. The catheter 51 is made of a synthetic resin in order to provide necessary antithrombogenicity and flexibility. During use, the catheter 51 is heated in the body temperature of the patient or in the balloon 52 during high-frequency energization. Therefore, the catheter 51 may be stretched in the length direction by an operation in use. When the catheter 51 is extended during use, operations such as inflation / deflation of the balloon 52 and withdrawal of the balloon 52 become difficult. Although heat softening can be avoided by providing a forced cooling mechanism having a high cooling capacity in the catheter 51, the attachment of the forced cooling mechanism having a high cooling capacity increases the diameter of the catheter 51, so that the catheter 51 becomes thicker and the catheter 51 becomes thicker. Another problem is that the introduction of 51 becomes difficult.

  This invention is made in view of such a situation, Comprising: It is providing the ablation catheter with a balloon which can avoid that a catheter elongates by operation in use and interferes with operation of a catheter. Objective.

  In order to achieve such an object, the present invention has the following configuration.

  That is, an ablation catheter with a balloon according to claim 1 is provided with an inflatable / deflatable balloon disposed on the distal end side of the catheter, an inner electrode for high-frequency energization installed in the balloon, and a balloon. In an ablation catheter with a balloon equipped with an installed temperature sensor, a non-elastic, non-metallic stretch prevention string that prevents the catheter from extending in the length direction is passed from the tip of the catheter to the hand. It is characterized by being.

  (Operation / Effect) When the target lesion site in the patient body is cauterized using the ablation catheter with a balloon of the invention of claim 1 (hereinafter abbreviated as “ablation catheter” where appropriate), the inflation is arranged on the distal end side of the catheter.・ Introduce percutaneously into the patient's body in a deflated balloon and allow the balloon to reach the target lesion site while pushing it with the catheter, and introduce the liquid into the balloon via the catheter and inflate it firmly. . Subsequently, the inflated balloon is brought into close contact with the target lesion site to be ablated, and high-frequency power is supplied to the patient body surface as a counter electrode of a high-frequency energizing inner electrode (hereinafter abbreviated as “inner electrode” where appropriate). High frequency energization is performed between a planar electrode for high frequency energization separately set at an appropriate position (hereinafter, abbreviated as “outer electrode” as appropriate). While performing heating by high-frequency dielectric heating and Joule heating, the heating temperature is detected by the temperature sensor in the balloon, and high-frequency power is supplied in a supply amount corresponding to the temperature measurement result of the temperature sensor. Temperature is controlled. As the high-frequency dielectric heating by the high-frequency energization and the heating by the Joule heat occur around the balloon, only the balloon contact portion at the target lesion site is heated together and locally cauterized.

  In the ablation catheter according to the first aspect of the present invention, the catheter is always moved from the vicinity of the distal end to the proximal end by an inelastic / non-metallic stretch prevention string delivered from the vicinity of the distal end to the proximal end. Since it is in the attracted state, for example, when the catheter is heat-softened during high-frequency energization, even if an operation is applied that applies a force in the direction of extending the catheter in the length direction, the extension preventing string is It prevents the heat-softened catheter from extending in the length direction. The non-elastic stretch preventing string does not stretch like a rubber strap by manipulating the catheter, but firmly attracts and softens the catheter, and in particular prevents the catheter from stretching due to thermal softening. Further, since the high-frequency power for heating does not invade the non-metallic stretch preventing string, loss of the high-frequency power for heating and heat generation of the string itself due to the intrusion of the high-frequency power can be avoided.

  Thus, in the case of the ablation catheter according to the first aspect of the present invention, the catheter is moved from the vicinity of the distal end to the proximal end by the non-elastic / non-metallic stretch prevention string delivered from the vicinity of the distal end to the proximal end. In addition to preventing the heat-softened catheter from extending in the length direction during high-frequency energization, the non-metallic stretch prevention string is used for heating. Therefore, the loss of heating high-frequency power and the heat generation of the string itself due to the high-frequency power penetration can be avoided. Therefore, according to the ablation catheter of the first aspect of the present invention, it is possible to prevent the catheter from being stretched by an operation in use and hindering the operation of the catheter.

  Further, the invention of claim 2 is the ablation catheter with balloon according to claim 1, wherein the non-elastic / non-metallic material of the string for preventing elongation is polyimide resin, polyester resin, polyethylene resin, carbon fiber, or aramid fiber. Is at least one of the following.

  According to the invention of claim 2, since the string for preventing elongation is made of a material that is not easily heat-softened, such as polyimide resin, polyester resin, polyethylene resin, carbon fiber, and aramid fiber, it is used for preventing elongation during use. As a result of continuously attracting the catheter toward the hand without being heat-softened, the string can surely prevent the catheter from being stretched by an operation in use.

  The invention according to claim 3 is the ablation catheter with a balloon according to claim 1 or 2, wherein the diameter of the string for preventing extension is 1 mm or less.

  (Operation / Effect) According to the invention of claim 3, since the diameter of the string for preventing elongation is 1 mm or less, even a thin catheter can be delivered without difficulty.

  According to a fourth aspect of the present invention, in the ablation catheter with a balloon according to any one of the first to third aspects, the catheter is concentrically threaded so that the outer cylindrical shaft and the inner cylindrical shaft are movable in the axial direction. The distal end of the balloon is fixed to the distal end of the inner cylindrical shaft, and the rear end of the balloon is fixed to the distal end of the outer cylindrical shaft. The electrode is shaped like a coil and is concentrically extrapolated to the inner cylinder shaft.

  (Function / Effect) According to the invention of claim 4, in addition to being able to change the shape of the balloon in various ways by moving the outer cylinder shaft or the inner cylinder shaft in the axial direction, the inner electrode for high-frequency energization Since the inner electrode for high frequency energization is substantially integrated with the inner cylinder shaft by concentrically extrapolating to the inner cylinder shaft, the introduction of the balloon becomes smoother.

  The invention according to claim 5 is the ablation catheter with balloon according to claim 4, wherein the extension preventing string is passed through the clearance between the outer cylinder shaft and the inner cylinder shaft, and the extension prevention string is used. The tip of the string is attached near the tip of the outer cylinder shaft.

  (Operation / Effect) According to the invention of claim 5, the clearance between the outer cylinder shaft and the inner cylinder shaft can be used for piping of the string for preventing elongation. Further, since the tip of the extension preventing string is attached in the vicinity of the tip of the outer cylinder shaft, the extension prevention string can prevent the outer cylinder shaft from being extended by an operation in use. In addition, since the vicinity of the tip of the inner cylinder shaft is also indirectly connected to the extension prevention string via the balloon, the extension of the inner cylinder shaft by the operation during use can be suppressed by the extension prevention string.

  According to a sixth aspect of the present invention, in the ablation catheter with a balloon according to the fourth or fifth aspect, the inner electrode for high-frequency energization is extrapolated to the inner cylindrical shaft without restricting the inner cylindrical shaft, and the outer cylindrical shaft In addition to being fixed to the side, the temperature sensor is fixed to the inner electrode for high-frequency energization.

  (Operation / Effect) According to the invention of claim 6, the inner cylindrical shaft can move smoothly without being restrained by the high frequency energizing inner electrode. Furthermore, since the inner electrode for high-frequency energization is fixed to the outer tube shaft to which the rear end of the balloon is fixed, and the temperature sensor is fixed to the inner electrode for high-frequency energization, The installation position of the inner electrode and the temperature sensor is stabilized.

  The invention of claim 7 is the ablation catheter with a balloon according to any one of claims 1 to 6, wherein the temperature is measured from a power supply lead wire for supplying high frequency power to the high frequency energization inner electrode and a temperature sensor. Each of the sensor lead wires for taking out signals is passed through the catheter with an electrically insulating protective coating.

  (Operation / Effect) According to the invention of claim 7, the sensor lead wire for taking out the temperature measurement signal from the temperature sensor and the power feeding lead wire for feeding the high frequency power to the high frequency energizing inner electrode are drawn to the catheter. Since it is passed, the catheter can also serve as a lead wire pipe. In addition, since both the sensor lead wire and the power supply lead wire have an electrically insulating protective coating, there is no risk of short-circuit between the lead wires, and at the same time, leakage and intrusion of high-frequency power can be suppressed. As a result, the heat generation of the catheter due to leakage and intrusion of high-frequency power is suppressed, and the forced cooling mechanism of the catheter can be omitted.

  The invention according to claim 8 is the balloon ablation catheter according to claim 7, wherein the electrically insulating protective coating of the power supply lead wire is made of a material having a relative dielectric constant smaller than that of polyvinyl chloride.

  (Operation / Effect) According to the invention of claim 8, the electrical insulating protective coating of the power supply lead wire is made of a material having a relative dielectric constant smaller than that of polyvinyl chloride, and the electrical insulating protective coating has an electrical insulating property. As a result, leakage / intrusion of high-frequency power is further suppressed, and heat generation of the catheter due to leakage / intrusion of high-frequency power is sufficiently suppressed.

  According to a ninth aspect of the present invention, in the ablation catheter with a balloon according to the seventh aspect, the electrically insulating protective coating of the sensor lead wire is made of a material having a relative dielectric constant smaller than that of polyvinyl chloride.

  According to the invention of claim 9, the electrical insulation protective coating of the sensor lead wire is made of a material having a relative dielectric constant smaller than that of polyvinyl chloride, and the electrical insulation of the electrical insulation protective coating is increased. In addition, heat generation of the catheter due to leakage / invasion is sufficiently suppressed.

  The invention of claim 10 is the ablation catheter with balloon according to any one of claims 1 to 9, wherein a forced cooling mechanism for the catheter is not provided.

  (Operation / Effect) According to the invention of claim 10, since the forced cooling mechanism of the catheter is omitted, the catheter can be made thinner and the catheter can be easily inserted into the patient.

  The invention of claim 11 is the ablation catheter with a balloon according to any one of claims 1 to 10, wherein the liquid feeding means for feeding the liquid into the balloon via the catheter and the temperature measurement result of the temperature sensor. Power supply means for supplying high-frequency power with a supply amount according to the above.

  According to the invention of claim 11, the balloon can be inflated firmly by feeding the liquid into the balloon through the catheter by the liquid feeding means. In addition, the heating temperature of the high-frequency dielectric heating and Joule heat can be accurately controlled by supplying high-frequency power with a supply amount corresponding to the temperature measurement result of the temperature sensor by the power supply means.

  According to a twelfth aspect of the present invention, in the ablation catheter with a balloon according to the eleventh aspect, the liquid fed by the liquid feeding means passes through a clearance between the outer cylinder shaft and the inner cylinder shaft.

  (Operation and Effect) According to the invention of claim 12, the clearance between the outer cylinder shaft and the inner cylinder shaft can be used as a flow path for liquid feeding by the liquid feeding means.

  The invention according to claim 13 is the ablation catheter with balloon according to claim 11 or 12, wherein the liquid in the balloon firmly inflated by the liquid fed by the liquid feeding means is allowed to enter and exit between the catheter and the balloon. And a liquid agitating means for agitating the liquid in the balloon.

  (Operation / Effect) According to the invention of claim 13, the liquid in the balloon in an inflated state is introduced between the catheter and the balloon by the liquid agitating means during the execution of heating by high frequency dielectric heating and Joule heat. When the liquid inside the balloon is moved in and out and the liquid inside the balloon is agitated, liquids with different temperatures are mixed together to make the liquid temperature inside the balloon uniform, and heating unevenness due to high frequency dielectric heating and Joule heat can be suppressed.

  As described above, in the case of the ablation catheter with a balloon according to the present invention, the catheter is moved from the vicinity of the distal end by the non-elastic / non-metallic stretch prevention string delivered from the vicinity of the distal end to the hand. Since it is in a state of being always attracted toward the hand, it is possible to prevent the heat-softened catheter from extending in the length direction, and the non-metallic stretch prevention string has a high frequency for heating. Since power does not enter, loss of heating high-frequency power and heat generation of the string itself due to intrusion of high-frequency power can be avoided. Therefore, according to the ablation catheter of the first aspect of the present invention, it is possible to prevent the catheter from being stretched by an operation in use and hindering the operation of the catheter.

  Hereinafter, embodiments of the ablation catheter with a balloon of the present invention will be described. FIG. 1 is a plan view showing the overall configuration of the ablation catheter according to the embodiment, FIG. 2 is a cross-sectional view showing the inside of the balloon of the ablation catheter of the embodiment, and FIG. FIG. The ablation catheter of this embodiment is suitable for performing pulmonary vein electrical isolation as a treatment for cardiac arrhythmia.

  In the ablation catheter of the embodiment, a balloon 2 that can be inflated and deflated is disposed on the distal end side of the catheter 1. The catheter 1 is a double tube type catheter in which an outer tube shaft 3 and an inner tube shaft 4 are concentrically threaded so as to be movable in the axial direction, and the distal end portion of the balloon 2 is fixed to the distal end of the inner tube shaft 4. The rear end portion of the balloon 2 is fixed to the front end of the outer cylinder shaft 3, and a liquid introduction port 2A is provided at the rear end of the balloon. In the case of the double tube type catheter 1, the shape of the balloon 2 can be variously changed by moving the outer tube shaft 3 or the inner tube shaft 4 in the axial direction. Therefore, in the present invention, the catheter 1 is preferably a double tube catheter, but the catheter 1 is not necessarily limited to a double tube catheter, and a single tube catheter may be used depending on the type of treatment. There is also.

  The length of the outer cylinder shaft 3 and the inner cylinder shaft 4 is about 1 m to about 1 m and several tens of centimeters. The outer diameter of the outer cylinder shaft 3 is about 3 mm to 5 mm, and the inner diameter is about 2 mm to 4 mm. The outer diameter of the inner cylinder shaft 4 is about 1 mm to 3 mm, and the inner diameter is about 0.5 mm to 2 mm. As the material of the outer cylinder shaft 3 and the inner cylinder shaft 4, a flexible material having excellent antithrombogenicity is used. Specifically, a fluororesin, a polyamide resin, a polyimide resin, etc. are mentioned, for example.

  As shown in FIG. 3, the balloon 2 has a conical shape (conical tip conical shape) whose diameter is reduced on the distal end side in the inflated state. The balloon 2 has a length (length d along the balloon center axis 2a that virtually connects the balloon tip and the balloon rear end) of about 20 mm to 40 mm, and the maximum outer diameter on the rear end side is about 10 mm to 40 mm. The film thickness is 100 μm to 300 μm. When the outer diameter of the balloon 2 has a conical outer shape with a tapered shape, the balloon can be prevented from entering the pulmonary vein, and the balloon 2 is inserted into the pulmonary vein opening by inserting the tip of the balloon 2 into the pulmonary vein opening. Therefore, the entire annular peripheral edge of the pulmonary vein opening can be surely cauterized. As the material of the balloon 2, a stretchable material excellent in antithrombogenicity is used. In particular, polyurethane-based polymer materials are preferable, and specific examples include thermoplastic polyether urethane, polyether polyurethane urea, fluorine polyether urethane urea, polyether polyurethane urea resin, and polyether polyurethane urea amide.

  Furthermore, in the case of the ablation catheter of the embodiment, an inner electrode 5 for high-frequency energization that is formed in a coil shape by winding an electric wire in the balloon 2 is installed, and liquid is supplied into the balloon 2 from the liquid inlet 2A. A liquid feeding device (liquid feeding means) 6 for feeding via the catheter 1 is connected to the distal end side of the catheter 1 via a four-way connector CN. As the electric wire of the inner electrode 5, a highly conductive metal wire such as a silver wire, a gold wire, a platinum wire, or a copper wire is used.

  The inner electrode 5 is concentrically inserted on the inner cylinder shaft 4 without restricting the inner cylinder shaft 4. The inner diameter of the inner electrode 5 is slightly larger than the outer diameter of the inner cylindrical shaft 4, and a slight gap is formed between the inner surface of the inner electrode 5 and the outer surface of the inner cylindrical shaft 4. Thus, when the inner electrode 5 is concentrically inserted into the inner cylinder shaft without restraining the inner cylinder shaft 4, the inner electrode 5 is substantially integrated with the inner cylinder shaft 4 and obstructs it. The inner cylinder shaft 4 can be moved very smoothly.

  The ablation catheter of the embodiment includes a planar high-frequency energizing outer electrode 7 as a counter electrode of the inner electrode 5, and the outer electrode 7 is placed at an appropriate position on the patient body surface, for example, a double-sided tape (not shown). ) Is pasted and set. During high-frequency dielectric heating and Joule heating, high-frequency current is applied between the inner electrode 5 and the outer electrode 7 to cause high-frequency dielectric heating and Joule heating. The appropriate temperature for tissue cauterization during heating by high-frequency dielectric heating and Joule heat is usually in the range of 50 ° C to 70 ° C.

  On the other hand, the liquid feeding device 6 is provided with a liquid feeding roller pump (not shown), and the liquid fed by the liquid feeding roller pump passes through the clearance between the outer cylinder shaft 3 and the inner cylinder shaft 4. Then, it is fed into the balloon 2 from the liquid inlet 2A. As the liquid is fed from the liquid feeding device 6 into the balloon 2, the balloon 2 is inflated firmly. That is, the clearance between the outer cylinder shaft 3 and the inner cylinder shaft 4 is a flow path for liquid feeding by the liquid feeding device 6.

  Further, in the case of the ablation catheter of the embodiment, a diaphragm type stirring mechanism (liquid) that stirs the liquid in the balloon 2 by moving the balloon 2 in and out of the balloon 2 through the catheter 1 by injecting the liquid. (Stirring means) 8 is provided. By the stirring by the stirring mechanism 8, liquids with different temperatures are mixed to make the liquid temperature in the balloon 2 uniform, and heating unevenness due to high frequency dielectric heating and Joule heat can be suppressed.

  Furthermore, in the ablation catheter of the embodiment, a temperature sensor 9 installed in the balloon 2, a high-frequency power source (power supply means) 10 that supplies high-frequency power with a supply amount corresponding to the temperature measurement result of the temperature sensor 9, and It has. The frequency of the high-frequency power ranges from several MHz to several hundred MHz, and is usually around 10 MHz. During execution of heating by high-frequency dielectric heating and Joule heat, the heating temperature is detected by the temperature sensor 9 in the balloon 2 and fed back to the high-frequency power source 10, and the high-frequency power source 10 responds to the temperature measurement result of the temperature sensor 9. By supplying high-frequency power with the supply amount, the heating temperature by high-frequency dielectric heating and Joule heat is controlled. In addition, the inner electrode 5 is fixed to the outer cylinder shaft 3 to which the rear end portion of the balloon 2 is attached, and the temperature sensor 9 is fixed to the inner electrode 5. As a result, the installation positions of the inner electrode 5 and the temperature sensor 9 in the balloon 2 are stabilized. The temperature sensor 9 is exemplified by a thermocouple, but is not limited to a thermocouple, and for example, a semiconductor type temperature measuring element or the like can be used.

  Further, as shown in FIG. 4, both the sensor lead wire 11 for extracting a temperature measurement signal from the temperature sensor 9 and the power feeding lead wire 12 for feeding high frequency power to the high frequency energizing inner electrode 5 are electrically insulating. With the protective coatings 13 and 14, the clearance between the outer tube shaft 3 and the inner tube shaft 4 of the catheter 1 is drawn through. That is, the clearance between the outer cylinder shaft 3 and the inner cylinder shaft 4 is used as piping for the sensor lead wire 11 and the power supply lead wire 12. In addition, since the sensor lead wire 11 and the power supply lead wire 12 are both provided with an electrically insulating protective coating 13, 14, there is no risk of short-circuiting between the lead wires, and at the same time, leakage of high-frequency power Intrusion is suppressed, and heat generation of the outer cylinder shaft 3 and the inner cylinder shaft 4 due to leakage and intrusion of high-frequency power is suppressed. As a result, in the case of the ablation catheter of the embodiment, the forced cooling mechanism of the catheter 1 is omitted. However, a forced cooling mechanism for the catheter 1 may be provided in the catheter 1 as necessary.

  Examples of the material for the sensor lead wire 11 and the power supply lead wire 12 include copper, silver, platinum, tungsten, and alloy wires. Further, when the electrical insulating protective coatings 13 and 14 are made of a material having a relative dielectric constant smaller than that of polyvinyl chloride, the electrical insulating properties of the electrical insulating protective coatings 13 and 14 are improved. The heat generation of the outer cylinder shaft 3 and the inner cylinder shaft 4 due to leakage and intrusion of high-frequency power is further suppressed. Further, the fact that the outer cylinder shaft 3 and the inner cylinder shaft 4 are made of a material having a relative dielectric constant smaller than that of polyvinyl chloride also prevents heat generation of the outer cylinder shaft 3 and the inner cylinder shaft 4 due to leakage and intrusion of high-frequency power. It is valid.

  In the case of the embodiment, the power supply lead wire 12 is also formed using the same copper wire as the inner electrode 5. However, the power supply lead wire 12 manufactured separately is connected to the inner electrode 5. It may be.

  As a material having a relative dielectric constant smaller than that of polyvinyl chloride, a material having a relative dielectric constant of 10 MHz at 3 or less, more preferably 10 MHz at a relative dielectric constant of 1 or less can be mentioned. This relative dielectric constant ε can be measured as follows.

ε = Cx / Co
However, Cx is the capacitance of the measuring capacitor Cs when the bridge is balanced Co is the capacitance of ε = 1 calculated from the area of the main electrode and the thickness of the test piece, and is calculated by the following equation.

Co = r ² /3.6t
r: radius of main electrode (cm), t: thickness of test piece (cm)
Specific examples of materials having a lower relative dielectric constant than polyvinyl chloride include fluorine polymer compounds such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene-6-fluoropropylene copolymer (FEP). Other examples include polyethylene, polypropylene, polyimide resin, polyamide resin, and the like. In addition, as an apparatus used for the measurement of the dielectric constant ε, for example, an RF impedance / material analyzer (HP4291A) manufactured by Hewlett-Packard Company may be used.

  Further, radiation shielding metal pipes 3A and 4A are attached to the tips of the outer cylinder shaft 3 and the inner cylinder shaft 4, and the tip and rear ends of the balloon 2 are attached to the metal pipes 3A and 4A, respectively. The outer cylinder shaft 3 and the inner cylinder shaft 4 are fixed. By providing the radiation shielding metal pipes 3A and 4A, when X-ray fluoroscopy is performed, the radiation shielding metal pipes 3A and 4A appear on the X-ray fluoroscopic image, so that the position of the balloon 2 in the patient body can be accurately determined. It becomes possible to grasp. Examples of the material of the radiation shielding metal pipes 3A and 4A include gold, platinum, and stainless steel.

  In the ablation catheter according to the embodiment, the non-elastic / non-metallic stretch preventing string 16 that prevents the heat-softened catheter 1 from extending in the length direction during the operation in use is disposed inside the catheter 1 in the vicinity of the distal end. From hand to hand. That is, the extension preventing string 16 is drawn through the clearance between the outer cylinder shaft 3 and the inner cylinder shaft 4, and the front end and the rear end of the extension prevention string 16 are near the front end and the rear end of the outer cylinder shaft 4. It is attached in the vicinity (end on the hand side). The clearance between the outer cylinder shaft 3 and the inner cylinder shaft 4 is also used for piping of the extension preventing string 16. The vicinity of the tip of the inner cylindrical shaft 4 is also indirectly connected to the extension preventing string 16 via the balloon 2.

  Therefore, since the outer cylinder shaft 3 is always attracted from the vicinity of the tip to the hand by the extension preventing string 16, the outer cylinder shaft 3 thermally softened by the extension preventing string 16 is prevented from extending in the length direction. it can. The vicinity of the tip of the inner cylinder shaft 4 is also indirectly connected to the extension preventing string 16 via the burr 2, and the inner cylinder shaft 4 is always attracted from the vicinity of the tip to the hand by the extension preventing string 16. Therefore, the extension preventing string 16 prevents the inner cylindrical shaft 4 that has been heat-softened during high-frequency energization from extending in the length direction during an operation in use. The non-elastic stretch preventing string 16 does not stretch like a rubber strap by the operation of the catheter 1, but attracts the catheter 1 firmly and prevents the heat-softened catheter 1 from stretching. Needless to say, the stretch prevention string 16 can prevent the catheter 1 from stretching due to causes other than thermal softening. Further, since the high-frequency power for heating does not enter the non-stretching string 16 that is non-metallic, loss of the high-frequency power for heating or heat generation of the string itself due to the intrusion of the high-frequency power can be avoided.

  As the string 16 for preventing elongation, a thread or a thin string made of an inelastic / nonmetallic material is used. The non-elastic / non-metallic material that is the material of the stretch prevention string 16 is suitably a material that is not easily heat-softened, such as polyimide resin, polyester resin, polyethylene resin, carbon fiber, and aramid fiber. When a string or string made of such a material is used as the stretch prevention string 16, the stretch prevention string 16 continues to attract the hand firmly without being softened even during heating, and the catheter 1 is in use. It is surely prevented from extending by the operation of.

  In addition, the outer diameter of the stretch preventing string 16 is preferably small, and the diameter is preferably 1 mm or less, and more preferably 0.5 mm or less. When the diameter of the stretch preventing string 16 is 1 mm or less, even the thin catheter 1 can be pulled through without difficulty.

  The elongation preventing string 16 preferably has a tensile strength of 1 GPa or more, a tensile modulus of 30 GPa or more, and an elongation at break of 8% or less. More preferably, the tensile strength is 2 GPa or more, the tensile modulus is 50 GPa or more, and the elongation at break is 4% or less.

  In the case of cauterizing the annular peripheral edge of the pulmonary vein opening using the ablation catheter of the embodiment, as in the conventional case, as shown in FIG. 5, the guide wire GW previously introduced into the patient's body percutaneously. The balloon 2 in the deflated state is pushed by the catheter 1 along the axis and is allowed to reach the left atrium from the inferior vena cava. The outer electrode 7 is attached with a double-sided adhesive tape (not shown), and high-frequency current is applied between the inner electrode 5 and the outer electrode 7 to heat and cauterize the annular peripheral edge of the pulmonary vein opening Qa. .

  Next, specific examples of the ablation catheter of the present invention will be described.

  [Example] First, a balloon 2 having a conical shape with a conical tip having a length of 30 mm at the front end of the balloon and a rear end of the balloon, a maximum outer diameter of 30 mm at the rear end, and a membrane thickness of 160 μm was prepared as follows. . That is, a glass balloon mold having a mold surface corresponding to a desired balloon shape is immersed in a 13% concentration polyurethane solution, and the solvent is evaporated by applying heat to form a urethane polymer film on the mold surface. Balloon 2 was produced by the method.

  On the other hand, a polyamide resin tube having an outer diameter of 3.8 mm, an inner diameter of 2.7 mm, and an overall length of 80 cm is prepared as the outer cylindrical shaft 3 of the catheter 1, while the stretch prevention string 16 has a diameter of 0.3 mm and a length of about 80 cm. Aramid fiber (trade name: Kevlar) was prepared. In addition, a stainless steel pipe having a diameter of 3.1 mm and a length of 7 mm and having a sandblasted outer surface was prepared as the metal pipe 3A. Then, the end of the aramid fiber as the extension preventing string 16 is sandwiched between the inner peripheral surface of the tube for the outer cylinder shaft and the outer peripheral surface of the stainless steel pipe for the metal pipe, and the stainless steel pipe is attached to the end of the tube. After being inserted and fitted, the aramid fibers were bound and fixed to the metal pipe 3A, and further, the aramid fibers were bound and fixed together with a 0.1 mm nylon thread. Next, the four-way connector CN is inserted into the rear end of the tube, and the rear end of the aramid fiber as the stretch prevention string 16 is inserted and fitted between the tube and the four-way connector. The four-way connector CN was tied and fixed to the base, and further, the aramid fiber was tied and fixed with a 0.1 mm nylon thread.

  On the other hand, a polyamide resin tube having an outer diameter of 1.5 mm, an inner diameter of 1.1 mm, and an overall length of 90 cm is used as the inner cylindrical shaft 4, and a stainless steel pipe having a diameter of 1.2 mm and a length of 6 mm and a sandblasted outer surface is used as the metal pipe 4A. After being inserted into the tip of the tube, it was tied and fixed with a 0.1 mm nylon thread. Then, after inserting the inner tube shaft 4 through the four-way connector CN, the cap of the four-way connector CN was tightened to produce the double tube catheter 1.

  Further, the tip portion of an electrical soft copper wire having a diameter of 0.5 mm subjected to silver plating of 0.1 μm is spirally wound over a length of 10 mm and shaped into a coil shape to form an inner electrode 5 and ethylene tetrafluoride An electrically insulating protective coating 14 was applied to other portions using a -6 fluoropropylene copolymer (FEP) to form a power feeding lead wire 12. Furthermore, as the temperature sensor 9, an ultrafine thermocouple double (copper-constantan) wire with poly (tetrafluoroethylene) and an electrically insulating protective coating 13 was prepared with a sensor lead wire 11.

  After the temperature sensor 9 is fixed to the inner electrode 5, the inner electrode 5 is inserted into the tip of the inner cylinder shaft 4, and then the sensor lead wire 11 and the power supply lead wire 12 are connected to the outer cylinder shaft 3 and the inner cylinder shaft. 4, the rear ends of the sensor lead wire 11 and the power supply lead wire 12 are pulled out from the four-way connector CN, and the sensor lead wire 11 and the tip end of the power supply lead wire 12 are pulled out. This was fixed to the metal pipe 3A with an aramid fiber fixture. Finally, the tip of the balloon 2 is tied and fixed to the metal pipe 4A with 0.1 mm nylon thread, and the rear end of the balloon 2 is tied and fixed to the metal pipe 3A with 0.1 mm nylon thread. An ablation catheter was completed.

  [Comparative Example] An ablation catheter of a comparative example was completed with the same configuration as that of the example except that the extension preventing string 16 was not attached.

  [Catheter Elongation Test] Subsequently, with respect to the ablation catheters of Examples and Comparative Examples, a heating test was performed by applying high-frequency electricity.

  The physiological saline was put in a sufficiently large water tank (not shown), and the temperature was set to 37 ° C. with a heater with a stirring function, and the outer electrode 7 was adhered to the outer surface of the water tank with a double-sided adhesive tape. Two such water tanks were prepared, and each of the balloons 2 of the ablation catheters of the examples and comparative examples were individually placed in the water tank for each catheter 1 and set at a position facing the outer electrode 7. At this time, the arrangement state of the balloon 2 with respect to each outer electrode 7 was made the same in the example and the comparative example. Furthermore, each catheter 1 was fixed so that it would not come off even if the tip of each catheter 1 was pulled slightly.

  On the other hand, two liquid delivery devices 6 and two high-frequency power sources 10 are prepared, and the sensor lead wires 11 of the ablation catheters of the example and the comparative example are connected to the temperature measurement signal input terminal of the high-frequency power source 10, and the inner electrode The power supply lead wire 12 of 5 and the power supply lead wire 15 of the outer electrode 7 were respectively connected to the high frequency power output terminal of the high frequency power source 10. The high frequency power supply 10 is set so as to control the supply amount of the high frequency power so that the heating temperature becomes 70 ° C. according to the intensity of the temperature measurement signal of the temperature sensor 9. The frequency of the high frequency power is about 13.6 MHz. Furthermore, after the liquid feeding device 6 is connected to the four-way connector CN and the contrast medium is fed as a liquid to the balloon 2 via the catheter 1 to inflate the balloon 2 firmly, high-frequency energization between the inner electrode 5 and the outer electrode 7 is performed. The ablation catheters of the example and the comparative example were simultaneously operated in parallel.

  Then, after the time required for cauterization of the four pulmonary vein openings has elapsed, the four-way connectors CN of the ablation catheters of the example and the comparative example are continuously pulled simultaneously with the strength when the ablation catheter is normally pulled out. I did it. In the comparative ablation catheter, the distal end of the catheter 1 was elongated for a while. However, although the ablation catheter of the example continued to be pulled for a while, the catheter 1 did not extend. As described above, in the above-described catheter elongation test, in the case of the ablation catheter of the embodiment, by attaching the stretch prevention string 16, it is possible to avoid a situation in which the catheter 1 is stretched by an operation in use and hinders the operation of the catheter 1. It was proved that we could do it.

  The present invention is not limited to the above-described embodiments, and can be modified as follows.

  (1) The ablation catheter of the embodiment has a configuration including all of the liquid feeding device 6, the high-frequency power source 10, or the outer electrode 7, but the liquid feeding device 6, the high-frequency power source 10 or the outer electrode 7 is actually used. Therefore, the ablation catheter of the present invention may be the catheter 1 that does not include the liquid feeding device 6, the high-frequency power source 10, or the outer electrode 7.

  (2) In the ablation catheter of the embodiment, only one extension preventing string 16 is delivered. However, a plurality of the extension preventing strings 16 are delivered in the catheter 1 except for the embodiment. The thing of the same structure as is mentioned as another embodiment.

  (3) In the ablation catheter of the embodiment, the outer shape of the balloon is a conical cone. However, the outer diameter of the balloon is not limited to the conical conical shape. It may be in a shape.

It is a top view which shows the whole structure of the ablation catheter of embodiment. It is sectional drawing which shows the inside of the balloon which concerns on embodiment. It is a front view which shows the external shape at the time of expansion | swelling of the balloon which concerns on embodiment. It is a transverse cross section of the catheter concerning an embodiment. It is a schematic diagram which shows the cauterization situation of the pulmonary vein opening by the balloon of embodiment. It is a schematic diagram which shows the cauterization situation of the annular peripheral part of the pulmonary vein opening by the ablation catheter with a balloon.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Catheter 2 ... Balloon 3 ... Outer cylinder shaft 4 ... Inner cylinder shaft 5 ... Inner electrode for high frequency electricity supply 6 ... Liquid delivery apparatus (liquid delivery means)
7 ... outer electrode for high frequency energization 8 ... Diaphragm type stirring mechanism (liquid stirring means)
9 ... Temperature sensor 10 ... High frequency power supply (power supply means)
DESCRIPTION OF SYMBOLS 11 ... Lead wire for sensors 12 ... Lead wire for electric power supply 13, 14 ... Electrical insulation protective coating 15 ... Lead wire for electric power supply 16 ... String for preventing elongation

Claims (13)

  An ablation catheter with a balloon comprising an inflatable / deflatable balloon disposed on the distal end side of the catheter, an internal electrode for high-frequency energization disposed in the balloon, and a temperature sensor disposed in the balloon An ablation catheter with a balloon, characterized in that a non-elastic, non-metallic stretch prevention string for preventing the catheter from extending in the length direction is handed over from the vicinity of the tip to the hand.   The ablation catheter with a balloon according to claim 1, wherein the non-elastic / non-metallic material of the string for preventing elongation is at least one of polyimide resin, polyester resin, polyethylene resin, carbon fiber, and aramid fiber. .   The ablation catheter with a balloon according to claim 1 or 2, wherein the diameter of the string for preventing extension is 1 mm or less.   The ablation catheter with a balloon according to any one of claims 1 to 3, wherein the catheter is a double tube catheter in which an outer tube shaft and an inner tube shaft are concentrically connected to each other so as to be movable in an axial direction. The tip of the balloon is fixed to the tip of the inner cylinder shaft, the rear end of the balloon is fixed to the tip of the outer cylinder shaft, and the inner electrode for high-frequency energization is shaped like a coil And an ablation catheter with a balloon that is concentrically extrapolated to the inner tube shaft.   5. The balloon ablation catheter according to claim 4, wherein the extension preventing string is passed through the clearance between the outer cylinder shaft and the inner cylinder shaft, and the tip of the extension preventing string is the tip of the outer cylinder shaft. Ablation catheter with balloon attached in the vicinity.   The ablation catheter with a balloon according to claim 4 or 5, wherein the inner electrode for high-frequency energization is extrapolated to the inner cylinder shaft without being constrained to the inner cylinder shaft and is fixed to the outer cylinder shaft side. An ablation catheter with a balloon in which a temperature sensor is fixed to an inner electrode for high-frequency energization.   The ablation catheter with a balloon according to any one of claims 1 to 6, wherein a power supply lead wire for supplying high-frequency power to the high-frequency energization inner electrode and a sensor lead wire for extracting a temperature measurement signal from the temperature sensor are provided. Both are ablation catheters with balloons that are passed through the catheter with an electrically insulating protective coating.   The ablation catheter with a balloon according to claim 7, wherein the electrically insulating protective coating of the lead wire for power supply is made of a material having a relative dielectric constant smaller than that of polyvinyl chloride.   The ablation catheter with a balloon according to claim 7, wherein the electrically insulating protective coating of the sensor lead wire is made of a material having a relative dielectric constant smaller than that of polyvinyl chloride.   The ablation catheter with a balloon according to any one of claims 1 to 9, wherein the catheter is not provided with a forced cooling mechanism.   The ablation catheter with a balloon according to any one of claims 1 to 10, wherein a high-frequency power is supplied with a supply amount according to a temperature measurement result of the temperature sensor and liquid supply means for supplying the liquid into the balloon via the catheter. Ablation catheter with balloon comprising power supply means for supplying.   The ablation catheter with a balloon according to claim 11, wherein the liquid fed by the liquid feeding means passes through a clearance between the outer cylinder shaft and the inner cylinder shaft. The ablation catheter with a balloon according to claim 11 or 12, wherein the liquid in the balloon in an inflated state is moved in and out between the catheter and the balloon by the liquid fed by the liquid feeding means, and the liquid in the balloon is agitated. An ablation catheter with a balloon provided with liquid stirring means.

Images