JP2005058504A - Ablation catheter with balloon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely and easily prevent a patient from getting burned on a body surface by high-frequency energizing for thermocautery. <P>SOLUTION: In an ablation catheter with a balloon of this invention, since the surface area of a planar outer electrode 7 for the high frequency energizing for performing the high-frequency energizing with a coil-like inner electrode 5 is equal to or wider than 50 square centimeters, high-frequency power is dispersed in a wide outer electrode surface and heat generation per unit area of the outer electrode 7 is small, there is no danger that the patient gets burned on the body surface by the high-frequency energizing. Also, since the surface area of the outer electrode 7 can be turned to 50 square centimeters or wider only by increasing the area of an electrode material, it is quite easy without any difficulties. Thus, by this invention, the patient is surely and easily prevented from getting burned on the body surface by the high-frequency energizing for performing the thermocautery. <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 heating with a high-frequency dielectric heating and Joule heating between the outer electrodes, and in particular a target lesion in a patient body. The present invention relates to a technique for preventing a patient from being burned on a body surface by high-frequency energization for performing cauterization of a part.

  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. 9, an inflatable / deflatable balloon 52 disposed on the distal end side of the catheter 51 is percutaneously inferior to 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 supplying a liquid containing a contrast medium into the balloon, is brought into close contact with the pulmonary vein opening Qa, the coiled inner electrode 53 for high-frequency energization installed in the balloon 52 is used. A high frequency power is supplied from a high frequency power supply 55 to the surface of the outer electrode 54 for high frequency energization set on the patient body surface as a counter electrode of the high frequency energization inner electrode 53.

  The annular peripheral edge of the pulmonary vein port Qa is entirely heated and cauterized by high-frequency dielectric heating and Joule heat that occur in association with high-frequency power supply between the high-frequency power supply inner electrode 53 and the high-frequency power supply outer electrode 54. 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 problem that the patient may be burned on the body surface due to high-frequency energization for cauterizing the target lesion site in the patient's body. The high frequency energization outer electrode 54 affixed to the patient's body surface may generate heat due to the high frequency energization and cause burns on the patient body surface. Patients who have lost their consciousness due to anesthesia should not be burned during the operation, and the treating side must be completely responsible for preventing it.

  The present invention has been made in view of such circumstances, and it is possible to reliably and easily prevent a patient from being burned on a body surface by high-frequency energization for performing cauterization of a target lesion site in a patient. An object of the present invention is to provide an ablation catheter with a balloon that can perform the above-mentioned.

  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 the ablation catheter with a balloon provided with an installed temperature sensor and a planar high-frequency energization outer electrode arranged as a counter electrode of the high-frequency energization inner electrode, the high-frequency energization outer electrode is 50 square centimeters or more. It has a surface area.

  (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. A percutaneous balloon is introduced into the patient's body percutaneously in a deflated state, and the balloon reaches the target lesion site while being pushed by the catheter, and a liquid is introduced into the balloon via the catheter and inflated. 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. The heating and Joule heating temperature is controlled. As heating by this high-frequency energization occurs around the balloon, only the portion of the target lesion site where the balloon is in close contact with the balloon is heated together and locally cauterized. For example, if the target lesion site is the pulmonary vein opening in the left atrium of the heart, only the annular peripheral edge of the pulmonary vein opening is cauterized as a whole.

  In the case of the ablation catheter according to the first aspect of the invention, since the outer electrode for high-frequency energization is planar and flexible, the outer electrode for high-frequency energization is attached to the patient's body surface with an adhesive or the like. In addition to being able to bend along the curved shape of the body surface and stick firmly to ensure sufficient electrical contact, the outer electrode for high-frequency energization has a surface area of 50 square centimeters or more, so the outer electrode has a wide high-frequency power The amount of heat generated per unit area of the outer electrode for high-frequency energization is reduced by being dispersed on the surface, and as a result, there is no concern that the patient will be burned on the body surface due to the high-frequency energization. In addition, since the surface area of the outer electrode for high-frequency energization can be as large as 50 square centimeters or more by simply increasing the area of the electrode material, there is no difficulty and it is quite simple.

  In other words, since the surface area of the outer electrode for high-frequency energization has not been sufficiently large in the past, the high-frequency power is concentrated on the surface of the outer electrode that is narrow, and the amount of heat generated per unit area of the outer electrode for high-frequency energization is large. The situation in which the patient was worried about burns on the body surface due to high-frequency energization was resolved. Therefore, according to the ablation catheter of the first aspect of the invention, it is possible to reliably and easily prevent the patient from being burned on the body surface by high-frequency energization for cauterizing the target lesion site in the patient.

  The invention according to claim 2 is the ablation catheter with balloon according to claim 1, wherein the surface area of the outer electrode for high-frequency conduction is 100 square centimeters or more.

  (Function / Effect) According to the invention of claim 2, the surface area of the outer electrode for high-frequency energization is sufficiently wide as 100 square centimeters or more. It can be said that the amount of heat generated per unit area is extremely small, and there is no concern that the patient may be burned by the high frequency energization.

  The invention according to claim 3 is the ablation catheter with a balloon according to claim 1 or 2, wherein the outer electrode for high-frequency energization divides the surface of the outer electrode for high-frequency energization into two or three sections approximately evenly. It is divided in the form.

  (Operation / Effect) According to the invention of claim 3, the outer electrode for high-frequency energization is divided so that the surface of the outer electrode for high-frequency energization is divided into two or three sections approximately equally. Since the outer electrode is composed of two (two-piece) or three (three-piece) divided outer electrodes having a substantially uniform surface area, sufficient electrical contact can be ensured at the same time, The outer electrode can be set quickly. When the outer electrode for high-frequency energization is a two-piece or three-piece, it is easier to bend each segmented outer electrode according to the curved shape of the patient's body surface than in the case of one-piece, and each segmented outer electrode is affixed more closely to the patient's body surface. As a result, sufficient electrical contact can be ensured. Also, if the number of divided outer electrodes exceeds three, the number of divided electrodes becomes too large due to the outer electrodes being cut off, and it takes time and labor to put them on, and the outer electrodes cannot be set quickly. If the number of divided outer electrodes is up to three, the outer electrodes can be set quickly.

  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.

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

  (Operation / Effect) According to the invention of claim 5, 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 6 is the ablation catheter with balloon according to any one of claims 1 to 5, 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 6, the lead wire for the sensor for taking out the temperature measurement signal from the temperature sensor and the lead wire for power supply for supplying the high frequency power to the inner electrode for high frequency energization 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.

  According to a seventh aspect of the present invention, in the ablation catheter with a balloon according to the sixth aspect, 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.

  (Effect / Effect) According to the invention of claim 7, 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.

  The invention according to claim 8 is the ablation catheter with balloon according to claim 6, 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.

  According to the invention of claim 8, the electrical insulating 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 insulating property of the electrical insulating protective coating is increased. In addition, heat generation of the catheter due to leakage / invasion is sufficiently suppressed.

  The invention of claim 9 is the ablation catheter with balloon according to any one of claims 1 to 8, wherein the forced cooling mechanism of the catheter is not provided.

  (Operation / Effect) According to the invention of claim 9, since the forced cooling mechanism of the catheter is omitted, it is possible to make the catheter thinner so that the catheter can be easily inserted into the patient.

  The invention of claim 10 is the ablation catheter with balloon according to any one of claims 1 to 9, wherein the inflated balloon has a conical outer shape whose diameter is reduced on the distal end side. is there.

  (Operation / Effect) According to the invention of claim 10, since the balloon has a conical outer shape whose diameter decreases on the distal end side, for example, the target lesion site to be ablated is the annular peripheral portion of the pulmonary vein opening. In some cases, by inserting the tip of the balloon a little into the pulmonary vein opening, the balloon can be tightly attached to the pulmonary vein opening, so that the entire annular peripheral edge of the pulmonary vein opening can be cauterized reliably. In addition, since the balloon can be prevented from entering the pulmonary vein, the inside of the pulmonary vein can be cauterized to prevent stenosis.

  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.

  (Operation / Effect) According to the invention of claim 11, the balloon can be inflated by feeding the liquid into the balloon via 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, according to the ablation catheter with a balloon according to the first aspect of the present invention, the outer electrode for high-frequency energization is planar and flexible, and thus is affixed to the patient body surface with an adhesive or the like. Sometimes the outer electrode for high-frequency energization bends along the curved shape of the patient's body surface and sticks tightly to ensure sufficient electrical contact. In addition, the outer electrode for high-frequency energization has a surface area of 50 square centimeters or more. Therefore, the high frequency power is dispersed on the surface of the wide outer electrode, and the amount of heat generated per unit area of the outer electrode for high frequency energization is reduced. As a result, the patient does not have to worry about burning the body surface due to the high frequency energization. In addition, since the surface area of the outer electrode for high-frequency energization can be as large as 50 square centimeters or more by simply increasing the area of the electrode material, there is no difficulty and it is quite simple. Therefore, according to the ablation catheter of the first aspect of the invention, it is possible to reliably and easily prevent the patient from being burned on the body surface by high-frequency energization for cauterizing the target lesion site in the patient.

  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 is preferable 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 shape with a tapered shape, the balloon can be prevented from entering the pulmonary vein, and the balloon 2 can be inserted into the pulmonary vein mouth by slightly inserting the tip of the balloon 2 into the pulmonary vein mouth. Since it is closely attached, the entire annular peripheral edge of the pulmonary vein opening can be reliably cauterized. As the material of the balloon 2, a stretchable material excellent in antithrombogenicity is used. Polyurethane polymer materials are particularly preferred, and specific examples include thermoplastic polyether urethane, polyether polyurethane urea, fluoropolyether urethane urea, polyether polyurethane urea resin, polyether polyurethane urea amide, and the like.

  Furthermore, in the case of the ablation catheter of the embodiment, an inner electrode for high-frequency energization (hereinafter abbreviated as “inner electrode” as appropriate) 5 formed by winding an electric wire around the balloon 2 and forming it in a coil shape is installed. 2, a liquid feeding device (liquid feeding means) 6 for feeding liquid from the liquid inlet 2A 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. While high-frequency dielectric heating and Joule heating are performed, high-frequency power is supplied between the inner electrode 5 and the outer electrode 7 as high-frequency power is supplied, thereby heating by high-frequency dielectric heating and Joule heat. Happens. The appropriate temperature for tissue cauterization during high frequency dielectric heating and Joule heating is usually in the range of 50 ° C to 70 ° C.

  In the case of the embodiment, the planar electrode 7 for high-frequency energization has a surface area of 50 square centimeters or more, and preferably has a surface area of 100 square centimeters or more. Since the outer electrode 7 is planar and flexible, when the outer electrode 7 is attached to the patient body surface with an adhesive or the like, the outer electrode 7 bends along the curved shape of the patient body surface and sticks tightly to make electrical contact. Can be secured sufficiently.

  As shown in FIG. 5, the outer electrode 7 may be composed of one (one piece) electrode as a whole, but the surface of the one piece outer electrode 7 in FIG. The configuration may be divided into three sections. Specifically, as shown in FIG. 6, it has a configuration composed of two (two-piece) divided electrodes 7 a 1 and 7 a 2 having substantially the same surface area, or as shown in FIG. The structure which consists of the division | segmentation electrodes 7b1-7b3 shape | molded by three (three piece) same rectangles which have the same surface area may be sufficient.

  In the case of the two-piece type outer electrode 7 made up of two divided electrodes 7a1 and 7a2 and the three-piece type outer electrode 7 made up of three divided electrodes 7b1 to 7b3, it is possible to ensure sufficient electrical contact, The outer electrode can be set quickly. Each divided electrode 7a1, 7a2 and each divided electrode 7b1-7b3 are bent according to the curved shape of the patient's body surface, compared to the one-piece non-divided outer electrode 7. It is easy and can be adhered to the patient body surface, so that sufficient electrical contact can be ensured. In addition, if the number of divided outer electrodes constituting one outer electrode exceeds three, the outer electrode 7 is cut into pieces and the number of divided electrodes becomes too large, and it takes time and effort to apply the divided electrodes. However, if the number of divided electrodes is two or three, the outer electrode 7 cannot be set quickly.

  The shape of the outer electrode 7 is not limited to the square shown in FIG. 5, but may be other shapes such as a rectangle or a circle. Further, the shape of the divided outer electrodes 7a1, 7a2, 7b1 to 7b3 is not limited to the rectangle shown in FIGS. 6 and 7, and may be other shapes such as a square or a circle. As the material of the outer electrode 7, for example, a thin plate or sheet made of a highly electrically conductive metal such as copper or aluminum is used.

  On the other hand, the liquid is fed into the balloon 2 from the liquid introduction port 2 </ b> A through the clearance between the outer cylinder shaft 3 and the inner cylinder shaft 4 by the liquid feeding device 6. 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 having different temperatures are mixed to make the liquid temperature in the balloon 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 are electrically insulated. With the coverings 13 and 14, the clearance between the outer cylinder shaft 3 and the inner cylinder 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 of the sensor lead wire 11 and the power supply lead wire 12 include copper, silver, platinum, tungsten, alloys, and the like.

  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
Where Cx is the capacitance of the measuring capacitor Cs when the bridge is balanced. However, Co is a 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 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, and polyamide resin. 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 case of cauterizing the annular peripheral portion of the pulmonary vein opening using the ablation catheter of the embodiment, as in the conventional case, as shown in FIG. 8, 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 an adhesive (not shown) or the like, high-frequency current is applied between the inner electrode 5 and the outer electrode 7, and the annular peripheral portion of the pulmonary vein port Qa is heated and cauterized.

  In the case of the ablation catheter of the embodiment having the above-described configuration, the high-frequency energization outer electrode 7 has a surface area of 50 square centimeters or more, so that high-frequency power is dispersed on the wide outer electrode surface, and the unit of the outer electrode 7 The amount of heat generated per area is reduced, and as a result, there is no risk that the patient will be burned on the body surface due to high-frequency conduction. Further, when the surface area of the outer electrode 7 is 100 square centimeters or more, the high frequency power is widely dispersed on the surface of the sufficiently large outer electrode, and the amount of heat generated per unit area of the outer electrode for high frequency conduction is further reduced. It can be said that there is no worry of burning the body surface.

  Further, it is possible to make the surface area of the outer electrode 7 for high-frequency energization more than 150 square centimeters or 200 square centimeters or more by simply increasing the area of the electrode material.

  Therefore, according to the ablation catheter of the embodiment, it is possible to reliably and easily prevent the patient from being burned on the body surface by high-frequency energization for cauterizing the target lesion site in the patient.

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

  [Example 1] 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 film thickness of 160 μm is prepared as follows. did. 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 used as the outer cylindrical shaft 3 of the catheter 1, and a stainless steel pipe having a diameter of 3.1 mm and a length of 7 mm and a sandblasted outer surface is used. The metal pipe 3A was inserted and fitted to the tip of the tube and then tied and fixed with a 0.1 mm nylon thread, and the four-way connector CN was inserted and fitted to the rear end and then 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. As shown in Fig. 1, the inner end of the tube 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 electric annealed 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 to be shaped into a coil to be an inner electrode 5 and ethylene tetrafluoride- An electrically insulating protective coating 14 was applied to other portions using a hexafluoropropylene copolymer (FEP) to obtain a power supply 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 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 was tied and fixed to the metal pipe 4A with 0.1 mm nylon thread, and the rear end of the balloon 2 was tied and fixed to the metal pipe 3A with 0.1 mm nylon thread. On the other hand, an aluminum sheet having a length and width of 15 cm (surface area of 225 square centimeters) and a thickness of 100 μm was separately prepared as the outer electrode 7 to complete the ablation catheter of Example 1.

  [Example 2] Also, as the outer electrode 7, except that the two divided electrodes 7a1 and 7a2 made of an aluminum sheet having a length of 15 cm and a width of 7.5 cm (surface area of 112.5 square centimeters) and a thickness of 100 μm were prepared, The same configuration as in Example 1 was completed as the ablation catheter of Example 2. Also in Example 2, the surface area of the outer electrode 7 as a whole is 225 square centimeters.

  [Comparative Example] An ablation catheter of a comparative example was completed with the same configuration as that of Example 1 except that the outer electrode 7 was 5 cm in length and width (surface area 25 square centimeters).

  [Heating test] Subsequently, the ablation catheters of Examples 1 and 2 and the comparative example were each subjected to a heating test by high-frequency dielectric heating and Joule heat by applying high-frequency electricity. Specifically, a block-like simulated living body (10 cm × 10 cm × 30 cm) heated to 37 ° C. was prepared, and a catheter was inserted so that a balloon was positioned at the center, and was closely adhered to the simulated living body. A chicken skin was attached to the surface of the simulated living body, and an outer electrode was further attached. In this state, a heating test was performed. A heat-sensitive seal was interposed between the outer electrode and the chicken skin. On the other hand, the sensor lead wire 11 is connected to the temperature measurement signal input terminal of the high frequency power source 10, and the power feeding lead wire 12 of the inner electrode 5 and the power feeding lead wire 15 of the outer electrode 7 are connected to the high frequency power source 10. Each was connected to a high frequency power output terminal. 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, the liquid feeding device 6 was connected to the four-way connector CN, and the contrast medium was fed as a liquid to the balloon 2 via the catheter 1 to inflate the balloon 2. And while operating the stirring mechanism 8, high-frequency power was supplied for a time required to cauterize the annular peripheral edge of the normal pulmonary vein opening. Further, during the supply of the high frequency power, the intensity of the temperature measurement signal of the temperature sensor 9 was continuously recorded by the recorder.

  During high-frequency energization, the heating temperature changed at an appropriate temperature in both Examples 1 and 2 and Comparative Example. After the heating test, the affixed outer electrode 7 was peeled off and the surface of the chicken skin was checked. In the case of Examples 1 and 2, no burns were observed. Has been observed. At this time, the temperature indicated by the heat-sensitive seal adhered between the outer electrode and the chicken skin was about 35 ° C. in the case of Examples 1 and 2, while that of the comparative example was about 65 ° C. ° C. Therefore, according to each of the ablation catheters of Examples 1 and 2 including the outer electrode 7 having a surface area of 150 square centimeters or more by the above-described heating test, it is ensured that the patient is burned on the body surface due to high-frequency energization. It was proved that it can be easily prevented.

  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.

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 top view which shows the example of a specific shape of the outer electrode which concerns on embodiment. It is a top view which shows the other specific example of a shape of the outer electrode which concerns on embodiment. It is a top view which shows the other specific example of a shape of the outer electrode which concerns on 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 electrodes for high-frequency energization 7a1, 7a2 ... divided outer electrodes 7b1 to 7b3 ... divided outer electrodes 8 ... diaphragm type stirring mechanism (liquid stirring means)
9 ... Temperature sensor 10 ... High frequency power supply (power supply means)
DESCRIPTION OF SYMBOLS 11 ... Sensor lead wire 12 ... Electric power supply lead wire 13, 14 ... Electrical insulation protective coating 15 ... Electric power supply lead wire

Claims (13)

  An inflatable / deflatable balloon disposed on the distal end side of the catheter, an inner electrode for high-frequency energization disposed in the balloon, a temperature sensor disposed in the balloon, and a counter electrode for the inner electrode for high-frequency energization An ablation catheter with a balloon provided with a planar high-frequency energization outer electrode arranged as described above, wherein the high-frequency energization outer electrode has a surface area of 50 square centimeters or more.   The ablation catheter with a balloon according to claim 1, wherein the surface area of the high-frequency energizing outer electrode is 100 square centimeters or more.   The ablation catheter with a balloon according to claim 1 or 2, wherein the outer electrode for high-frequency energization is divided in such a manner that the surface of the outer electrode for high-frequency energization is divided into two or three sections approximately evenly. catheter.   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 in a manner 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 into a coil And an ablation catheter with a balloon that is concentrically extrapolated to the inner tube shaft.   In the ablation catheter with a balloon according to claim 4, in addition to being fixed to the outer cylinder shaft side, the inner electrode for high-frequency energization is extrapolated to the inner cylinder shaft without restraining the inner cylinder shaft, 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 5, 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 6, 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.   The ablation catheter with a balloon according to claim 6, 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 8, wherein a forced cooling mechanism for the catheter is not provided.   The ablation catheter with a balloon according to any one of claims 1 to 9, wherein the balloon in an inflated state has a conical outer shape whose diameter is reduced on the distal end side.   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.

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