Dual-energy ablation catheter and dual-energy ablation method based on dual-energy ablation catheter

Abstract

Disclosed in the present application are a dual-energy ablation catheter and a dual-energy ablation method based on the dual-energy ablation catheter. The dual-energy ablation catheter comprises a catheter main body, and an expandable element and an ablation electrode which are arranged at the distal end of the catheter main body. The expandable element is adapted to expand outward after a coolant is introduced into an inner cavity of the expandable element, and freeze a target tissue to form a frozen tissue region in a frozen state. The ablation electrode is adapted to perform pulse ablation on target tissues in the frozen tissue region and a region adjacent thereto. The expandable element is a balloon. First, the expandable element is used to freeze the target tissue to form the frozen tissue region in the frozen state, and then the ablation electrode is used to perform pulse discharge on the target tissues in the frozen tissue region and the region adjacent thereto. Since the pulse current is constrained by frozen objects in the frozen tissue region, the energy of the pulse current is more constrained in the frozen tissue region and the region adjacent thereto, and the energy leakage of the pulse current is less, so that the damage caused by the pulse current to non-target tissues can be reduced, thereby improving the effectiveness and safety of pulse ablation.

Description

Dual-energy ablation catheter and dual-energy ablation method based on dual-energy ablation catheter

[0001] This application claims priority to the Chinese patent application No. 202411092598.1, filed on August 9, 2024, and entitled "Dual-energy ablation catheter and dual-energy ablation method based on dual-energy ablation catheter", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of interventional medical devices, in particular to a dual-energy ablation catheter and a dual-energy ablation method based on the dual-energy ablation catheter.

[0003] Although the present application is mainly applicable to cardiac ablation surgery, such as the treatment of atrial fibrillation, however, the present application can also be applicable to the targeted ablation of pathological tissues in other medical fields, including the field of oncology, the field of neurology, and the field of interventional radiology. BACKGROUND

[0004] Atrial fibrillation is a common arrhythmia characterized by irregular and rapid electrical signals in the atria (upper chambers of the heart). These abnormal signals can lead to reduced blood pumping, which can cause symptoms such as palpitations, fatigue, and shortness of breath. Studies have shown that catheter ablation technology can successfully electrically isolate the pulmonary veins, effectively preventing the recurrence of atrial fibrillation, and is an effective means for atrial fibrillation patients to restore and maintain sinus rhythm.

[0005] Traditionally, thermal ablation using radiofrequency (RF) catheters is the standard treatment for atrial fibrillation. Radiofrequency ablation mainly converts electrical current into heat energy through the impedance of the tissue when the current flows through the tissue, and this heat energy is then conducted and radiated to the adjacent tissue to cause small-scale tissue damage, i.e., so-called point-by-point ablation, which completes segmental or circumferential pulmonary vein electrical isolation, forming complete electrical isolation of the pulmonary vein-left atrium, i.e., PVI. This technique is relatively difficult to operate, has a long ablation time, a long learning curve, and requires a high level of operator skill, and the patient experiences significant pain during the procedure. In addition, a portion of patients cannot form a transmural lesion when the pulmonary vein is ablated by radiofrequency, which easily forms a pulmonary vein leak, leading to the recurrence of atrial fibrillation.

[0006] In recent years, cryoablation and pulsed field ablation have gradually become new ablation methods for catheter ablation treatment of atrial fibrillation. However, the probability of some complications (such as phrenic nerve injury, atrial esophageal fistula, etc.) caused by cryoablation can still be as high as 5%, and once some complications occur, the consequences are relatively serious. Pulsed field ablation, also known as FPA, is a non-thermal tissue ablation technique, which uses high-amplitude pulsed electric fields to generate irreversible electroporation in tissues, causing apoptosis, and achieving the purpose of non-thermal ablation. Pulsed field ablation has no effect on the esophagus and diaphragm, so the risk of complications such as phrenic nerve injury, atrial esophageal fistula, etc. caused by pulsed field ablation is lower than that of cryoablation. However, part of the energy generated by the electrode during pulsed field ablation can easily leak to the tissues or cells (including blood) around the target, easily causing blood hemolysis, microbubbles, coronary artery spasm, and other new symptoms different from traditional cryoablation, and the safety is lower.

[0007] Therefore, it is necessary to propose a new ablation catheter with good ablation treatment effect, fewer complications, and higher safety.

[0008] In addition to treating atrial fibrillation, the demand for minimally invasive ablation technology is also growing in the following fields: treating solid tumors (such as tumors in the lungs, liver, or kidneys), treating neurological diseases (such as epilepsy or movement disorders), and pain management through targeted nerve ablation. If there is the ability to confine and focus pulsed electric fields within the tissue freezing zone, it will have a great advantage in these application scenarios, especially when tissue protection and precision are very critical. SUMMARY

[0009] Therefore, the technical problem to be solved by the present application is to overcome the defects of poor treatment effect and high risk of complications of existing cryoablation and pulsed field ablation in ablation treatment of atrial fibrillation, and to provide a dual-energy ablation catheter and a dual-energy ablation method based on the dual-energy ablation catheter.

[0010] Although the following technical solutions are mainly described in the case of treating atrial fibrillation, however, the structure and combined synergistic ablation mechanism of the dual-energy ablation catheter disclosed in the present application are also applicable to other anatomical targets, such as tumors, neural tissue, and vascular malformations.

[0011] To solve the above technical problems, the technical solutions of the present application are as follows:

[0012] A dual-energy ablation catheter comprises a catheter body, an expandable element and a plurality of ablation electrodes disposed at the distal end of the catheter body, the expandable element being adapted to expand outwardly after the coolant is introduced into the inner cavity of the expandable element, the expanded expandable element being adapted to freeze the target tissue and form a tissue freezing area in the frozen state on the target tissue, and the plurality of ablation electrodes being adapted to pulse ablate the target tissue of the tissue freezing area and its adjacent area, wherein the expandable element is a balloon.

[0013] Optionally, the catheter body comprises an inner tube and an outer tube, the inner tube passing through the inner part of the outer tube, the balloon being connected to the outer wall of the outer tube, a medium conveying channel being formed between the inner tube and the outer tube, and a through hole being provided on the tube wall of the outer tube to communicate the medium conveying channel and the inner cavity of the balloon.

[0014] Optionally, a push tube is further provided, the push tube being slidingly disposed inside the catheter body, an end of the distal end of the push tube being connected with an ablation catheter, and the ablation electrodes being disposed on the ablation catheter; the ablation catheter has a storage state of being accommodated inside the catheter body and a natural expansion state of extending outwardly from the distal end of the catheter body and expanding outwardly under the pushing action of the push tube.

[0015] Optionally, the ablation catheter further has a taut state of being bent towards the outer periphery of the balloon under the action of an external force; when the ablation catheter is in the taut state, the ablation electrodes on the ablation catheter are in close contact with the target tissue of the tissue freezing area and its adjacent area to pulse ablate the target tissue.

[0016] Optionally, the ablation catheter is made of a shape memory alloy.

[0017] Optionally, the ablation catheter comprises a proximal catheter segment and a distal catheter segment, one end of the proximal catheter segment being connected to the distal end of the push tube, and the distal catheter segment being connected to the other end of the proximal catheter segment; when the ablation catheter is in the natural expansion state, the distal catheter segment is bent relative to the proximal catheter segment towards a direction deviating from the axis of the push tube; and a plurality of the ablation electrodes are disposed on the distal catheter segment.

[0018] Optionally, the proximal catheter segment is connected with a pull wire, the other end of the pull wire being connected to an operating handle, and the operating handle drives the ablation catheter to bend towards the balloon through the pull wire.

[0019] Optionally, the ablation catheter has a plurality of, and a plurality of the ablation electrodes are uniformly spaced along the length direction of the distal catheter segment; when the ablation catheter is in the taut state, a plurality of the ablation catheters are uniformly spaced around the circumference of the balloon.

[0020] Optionally, the balloon comprises a first balloon and a second balloon, the second balloon is located at the distal end of the first balloon, the outer diameter of the first balloon is larger than the outer diameter of the second balloon; when the ablation catheter is in the taut state, the ablation catheter is wrapped around the outer periphery of the second balloon.

[0021] Optionally, when the ablation catheter is in the natural expanded state of extending outward from the distal end of the catheter body, the ablation catheter is annular, and the plurality of ablation electrodes are annular electrodes that are spaced and sleeved on the outer periphery of the ablation catheter in the extension direction of the ablation catheter.

[0022] Optionally, the coolant input into the expandable element is liquid ethanol with a temperature lower than -40℃.

[0023] Optionally, the plurality of ablation electrodes are attached to the outer wall of the expandable element, and the plurality of ablation electrodes are attached to the outer wall of the tissue icing area (4) along with the expansion of the expandable element to perform pulsed ablation on the target tissue of the tissue icing area and its adjacent area.

[0024] The application also provides a dual-energy ablation method based on a dual-energy ablation catheter, comprising the following steps:

[0025] Delivering the dual-energy ablation catheter to the area where the target tissue is located; wherein the dual-energy ablation catheter comprises a catheter body and an expandable element and a plurality of ablation electrodes arranged at the distal end of the catheter body, wherein the expandable element is a balloon;

[0026] Inputting coolant into the inner cavity of the expandable element through the catheter body, the inner cavity of the expandable element expands outward after the coolant is input, and the expanded expandable element freezes the target tissue and forms a tissue icing area in an icing state on the target tissue;

[0027] The plurality of ablation electrodes are attached to the tissue icing area in an icing state, and the plurality of ablation electrodes release electric pulses through the ice in the tissue icing area to perform pulsed field ablation on the target tissue.

[0028] Optionally, the tissue icing area in an icing state comprises a tissue cryoablation area surrounding the outer periphery of the expanded expandable element and a tissue cryoicing area located outside the tissue cryoablation area; wherein the temperature of the tissue cryoablation area is lower than the temperature of the tissue cryoicing area, and the damage degree of the target tissue in the tissue cryoablation area under the action of low-temperature freezing is higher than the damage degree of the target tissue in the tissue cryoicing area under the action of low-temperature freezing;

[0029] The plurality of ablation electrodes release electric pulses to perform pulsed field ablation on the target tissue in the tissue cryo-frozen region and its adjacent region under the constraint of the ice in the tissue cryo-frozen region, so as to improve the damage degree of the target tissue in the tissue cryo-frozen region and its adjacent region.

[0030] Optionally, the temperature of the tissue cryo-ablation region is equal to or less than-20℃, and the temperature of the tissue cryo-frozen region is equal to or less than 0℃.

[0031] Optionally, the cryogen input into the expandable element is liquid ethanol with a temperature lower than-40℃.

[0032] The dual-energy ablation catheter provided by the application utilizes the properties that the electric field attenuates faster in the ice block, the electric potential difference of the electric field in the ice block is larger, and the ice block is easy to confine the electric field inside the ice block; in the ablation treatment process, the cryogen in the balloon is used to freeze the target tissue first, so that a tissue icing area in an icing state is quickly formed on the target tissue, the temperature of the part of the target tissue relatively close to the expandable element in the tissue icing area is relatively low (usually the temperature is lower than -20℃ or -40℃), the damage degree of this part of the target tissue in the freezing process is large, and the cryoablation effect is good, the temperature of another part of the target tissue relatively far away from the expandable element in the tissue icing area is relatively high (usually the temperature is lower than 0℃), the damage degree of this part of the target tissue in the freezing process is small, and the cryoablation effect is poor; then, the multiple ablation electrodes are used to pulse discharge the target tissue in the tissue icing area and the adjacent area, the pulse electric field performs pulse field ablation on the selected target tissue in the tissue icing area and the adjacent area, especially the part of the target tissue in the tissue icing area with a relatively high temperature and a small damage degree in the freezing process, the damage degree of this part of the target tissue after pulse ablation is further increased, and the ablation effect of this part of the target tissue is improved, so that the effective area of the traditional cryoablation is expanded from the boundary of -20℃ or -40℃ to the boundary of the entire tissue icing area below 0℃, the organic combination of the cryoablation and the pulse field ablation is realized, and the ablation treatment effect is better than that of the ablation treatment mode in which the cryoablation and the pulse field ablation are alternately performed. Moreover, since the pulse current is subjected to the confinement of the tissue icing area in the icing state, the energy of the pulse current generated by the ablation electrode is more confined in the tissue icing area and the adjacent area (it should be noted that the action range of the pulse field ablation includes not only the above part of the target tissue in the tissue icing area, but also the part of the target tissue in the adjacent area outside the tissue icing area), so the energy of the pulse current is less leaked to other tissues or cells (including blood) outside the target tissue to be ablated, the harm of the pulse current to the non-target tissue is reduced, and thus the occurrence probability of the complications such as hemolysis, micro-bubbles, and coronary artery spasm of blood in the ablation treatment process is reduced, and the effectiveness and safety of the pulse ablation are improved. In addition, the electric potential difference of the pulse electric field in the ice block is larger, and the pulse ablation effect on the target tissue can be further improved. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0034] Fig. 1 is a structural schematic diagram of a dual-energy ablation catheter for ablation treatment of a pulmonary vein according to an embodiment of the present application;

[0035] Fig. 2 is a structural schematic diagram of the dual-energy ablation catheter according to an embodiment of the present application, in which the balloon is in an inflated state and the ablation catheter is in a storage state;

[0036] Fig. 3 is a structural schematic diagram of the dual-energy ablation catheter according to an embodiment of the present application, in which the balloon is in an inflated state and the ablation catheter is in a natural expanded state;

[0037] Fig. 4 is a right view of Fig. 3;

[0038] Fig. 5 is a structural schematic diagram of the dual-energy ablation catheter according to an embodiment of the present application, in which the balloon is in an inflated state and the ablation catheter is in a taut state;

[0039] Fig. 6 is a right view of Fig. 5;

[0040] Fig. 7 is a structural schematic diagram of a dual-energy ablation catheter for ablation treatment of a pulmonary vein according to another embodiment of the present application;

[0041] Fig. 8 is a structural schematic diagram of a dual-energy ablation catheter for ablation treatment of a pulmonary vein according to another embodiment of the present application;

[0042] Fig. 9 is a structural schematic diagram of a dual-energy ablation catheter for ablation treatment of a pulmonary vein according to another embodiment of the present application.

[0043] Reference signs: 1, catheter main body; 11, inner tube; 12, outer tube; 121, through hole; 2, balloon; 2a, first balloon; 2b, second balloon; 3, ablation electrode; 4, tissue icing area; 5, push tube; 6, ablation catheter; 61, proximal catheter segment; 62, distal catheter segment; 7, pull wire; 8, pulmonary vein. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0045] In the description of the present application, it should be understood that the terms "proximal" and "distal" are relative to the operator, and in use of the present application, the end close to the doctor or operator is "proximal", i.e. the end where the operator is, and the end away from the doctor or operator is "distal", i.e. the end where the balloon is. The above description of the orientation is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application.

[0046] Embodiment one

[0047] A dual-energy ablation catheter as shown in FIGS. 1-6 includes a catheter body 1, an expandable element, an ablation catheter 6 and a plurality of ablation electrodes 3. The distal end of the catheter body 1 is adapted to extend through a blood vessel or other tissue passage in a living body to a target tissue, and the proximal end of the catheter body 1 is connected with an operating handle. In this embodiment, the expandable element is specifically a balloon 2, the balloon 2 and the ablation catheter 6 are arranged on the catheter body 1, and the plurality of ablation electrodes 3 are arranged on the ablation catheter 6.

[0048] The catheter body 1 includes an inner tube 11 and an outer tube 12, the inner tube 11 passes through the inside of the outer tube 12, the balloon 2 is sealingly connected to the outer wall of the distal end of the outer tube 12, a medium conveying passage is formed between the inner tube 11 and the outer tube 12, and a through hole 121 is provided on the tube wall of the outer tube 12 to communicate the medium conveying passage and the inner cavity of the balloon 2. The external coolant can flow to the inner cavity of the balloon 2 through the medium conveying passage and the through hole 121 in sequence, the balloon 2 expands outward after the coolant is introduced, and the expanded balloon 2 can freeze the target tissue and quickly form a tissue freezing area 4 in the frozen state on the target tissue (for example, at the opening position of the pulmonary vein 8 and the left atrium in FIG. 1). The plurality of ablation electrodes 3 are connected with an external pulse generator, and the pulse generator provides electric pulses to the ablation electrodes 3 to pulse ablate the target tissue of the tissue freezing area 4 and its adjacent area.

[0049] In some embodiments, the catheter body 1 further comprises a push tube 5, the push tube 5 is slidingly arranged inside the inner tube 11, the ablation catheter 6 is connected to the distal end of the push tube 5, and the proximal end of the push tube 5 is connected to an operating handle, which can control the sliding of the push tube 5 in the inner tube 11 to make the ablation catheter 6 retract into the inner tube 11 or extend out of the distal end of the inner tube 11. The ablation electrode 3 is electrically connected to an external pulse generator through a conductive structure in the push tube 5. The ablation catheter 6 has a retracted state of being accommodated inside the inner tube 11 and a natural expanded state of extending out of the distal end of the inner tube 11 and being unfolded outward under the pushing action of the push tube 5; the ablation catheter 6 also has a taut state of being bent towards the outer periphery of the balloon 2 under the action of an external force. During the ablation treatment, the balloon 2 is inflated to adhere to the inner wall of the target tissue (for example, the inner wall of the left atrium in FIG. 1) to freeze the target tissue, and the target tissue (including blood in the pulmonary vein 8 and the left atrium) on the outer periphery of the balloon 2 is quickly frozen to form an ice ball in a low-temperature state. The ablation catheter 6 adheres to the inner wall of the pulmonary vein 8 under the constraint of the inner wall of the pulmonary vein 8, at this time the ablation catheter 6 is in the taut state, the ablation electrode 3 on the ablation catheter 6 is in contact with the inner wall of the pulmonary vein 8, and the ablation electrode 3 can perform pulse ablation on the tissue of the inner wall of the pulmonary vein 8 in the ice freezing area 4 through the pulse electric field. Since the ablation catheter 6 is in the taut state, the ablation electrode 3 on the ablation catheter 6 can maintain more close contact with the tissue of the inner wall of the pulmonary vein 8, thereby improving the pulse ablation effect. After the ablation is completed, the push tube 5 can be retracted to make the ablation catheter 6 retreat into the inner tube 11 again.

[0050] In some embodiments, the ablation catheter 6 is made of a shape memory alloy, and when the ablation catheter 6 extends out of the end of the inner tube 11, the ablation catheter 6 is unfolded outward under the action of the shape memory function of itself, so that the distal end of the ablation catheter 6 is inclined to the direction deviating from the axis of the catheter body 1, thereby avoiding the distal end of the ablation catheter 6 from injuring the target tissue. Specifically, the ablation catheter 6 comprises an integral proximal catheter segment 61 and a distal catheter segment 62, one end of the proximal catheter segment 61 is connected to the distal end of the push tube 5, and the distal catheter segment 62 is connected to the other end of the proximal catheter segment 61. When the ablation catheter 6 is in the natural expanded state, the distal catheter segment 62 is bent relative to the proximal catheter segment 61 to the direction deviating from the axis of the push tube 5. The plurality of ablation electrodes 3 are arranged on the distal catheter segment 62 and uniformly spaced along the length direction of the distal catheter segment 62. The ablation catheter 6 has a plurality of ablation catheters 6, and when the plurality of ablation catheters 6 are all in the taut state, the plurality of ablation catheters 6 are uniformly spaced around the circumference of the balloon 2.

[0051] In some embodiments, the proximal catheter segment 61 is connected with a pull wire 7, the other end of the pull wire 7 is connected to an operating handle, and the operating handle drives the ablation catheter 6 to bend towards the balloon 2 through the pull wire 7. The arrangement of the pull wire 7 facilitates the ablation catheter 6 in the natural expanded state to be pulled to the taut state, and the ablation catheter 6 in the taut state can better conform to the target tissue, thereby improving the pulse ablation effect of the ablation electrodes 3 on the target tissue at the target point position.

[0052] In some embodiments, the coolant input into the balloon 2 is liquid ethanol with a temperature lower than -40°C. The conventional coolant in the balloon 2 is generally low-temperature gaseous coolant, such as nitrogen or dinitrogen oxide; the unit volume of the gaseous coolant has a small cooling capacity, and once these gaseous coolants leak at the connection of the balloon 2, they can cause serious damage to the human nervous system; while the unit volume of the liquid ethanol has a large cooling capacity, which can not only make the tissue around the balloon 2 quickly freeze to form the tissue icing area 4, but also is not easy to leak, and even if a small amount of leakage, the harm to the human body is relatively small.

[0053] The dual-energy ablation catheter provided by the embodiment utilizes the properties that electric field attenuates faster in the ice block, the electric potential difference of the electric field in the ice block is larger, and the ice block is easy to confine the electric field inside the ice block. During the ablation treatment, the cryogen in the balloon 2 is used to freeze the target tissue, so that a tissue icing area 4 in the icing state is quickly formed on the target tissue. The temperature of the part of the target tissue in the tissue icing area 4 that is relatively close to the balloon 2 is relatively low (usually lower than -20℃ or -40℃), the damage degree of this part of the target tissue during the freezing process is large, and the freezing ablation effect is good. The temperature of another part of the target tissue in the tissue icing area 4 that is relatively far away from the balloon 2 is relatively high (usually lower than 0℃), the damage degree of this part of the target tissue during the freezing process is small, and the freezing ablation effect is poor. Then, the multiple ablation electrodes 3 are used to pulse discharge the target tissue in the tissue icing area 4. The pulse electric field performs pulse field ablation on the selected target tissue in the tissue icing area 4. In particular, the damage degree of the part of the target tissue in the tissue icing area that has a relatively high temperature and a small damage degree during the freezing process is further increased after the pulse ablation, and the ablation effect of this part of the target tissue is improved. Thus, the effective area of the traditional freezing ablation is expanded from the -20℃ or -40℃ boundary to the 0℃ boundary of the entire tissue icing area, the organic combination of the freezing ablation and the pulse field ablation is realized, and the ablation treatment effect is better than that of the ablation treatment mode in which the freezing ablation and the pulse field ablation are alternately performed. Moreover, since the pulse current is subjected to the confining action of the tissue icing area 4 in the icing state, the energy of the pulse current generated by the ablation electrode 3 is more confined in the tissue icing area 4 and the adjacent area thereof (it should be noted that the action range of the pulse field ablation includes not only the above-mentioned part of the target tissue in the tissue icing area, but also the part of the target tissue in the adjacent area outside the tissue icing area within a certain range). Therefore, the energy of the pulse current is less leaked to other tissues or cells (including blood) outside the target tissue to be ablated, the harm of the pulse current to the non-target tissue is reduced, and thus the occurrence probability of the complications such as hemolysis, micro-bubbles, and coronary artery spasm of blood during the ablation treatment is reduced, and the effectiveness and safety of the pulse ablation are improved. In addition, the electric potential difference of the pulse electric field in the ice block is larger, and the pulse ablation effect on the target tissue is further improved.

[0054] Moreover, the dual-energy pulse ablation method in the embodiment uses the inflatable balloon 2 to cool the target tissue, and then uses the ablation catheter 6 with the ablation electrode 3 to pulse ablate the target tissue; compared with the prior art method of using a ring-shaped catheter to cool the target tissue, and then using multiple electrodes arranged on the ring-shaped catheter to pulse ablate the target tissue, the ablation electrode 3 in the embodiment is easier to be attached to the target position of the target tissue for pulse ablation, has better effectiveness, and the electrode design is simpler, and the problem of the ring-shaped catheter being too large in size to effectively obtain the accurate electrocardiogram of the inner wall tissue at the opening of the pulmonary vein 8 through the electrodes is avoided.

[0055] To ensure that the ablation electrode 3 pulse ablates after the target tissue is cooled to form the tissue icing area 4, the difference in the feedback ultrasonic signal before and after the target tissue icing can be used to determine whether the target tissue is iced to form the tissue icing area 4 through ultrasonic detection of the target tissue. When the ultrasonic detection result shows that the target tissue is iced to form the tissue icing area 4, the ablation electrode 3 is then provided with a pulse current for pulse ablation. Of course, the target tissue icing to form the tissue icing area 4 can also be determined by controlling the input dose (time, flow rate, power, etc.) of the coolant, and the target tissue icing to form the tissue icing area 4 can also be determined by measuring physical quantities such as the resistance of the target tissue.

[0056] Embodiment Two

[0057] A dual-energy ablation catheter as shown in FIG. 7 differs from the embodiment one in that the balloon 2 on the catheter body 1 includes a first balloon 2a and a second balloon 2b that can be inflated after the coolant is introduced, the second balloon 2b is located at the distal end of the first balloon 2a, and the outer diameter of the first balloon 2a after inflation is larger than that of the second balloon 2b after inflation; the second balloon 2b after inflation is adapted to be in close contact with the inner wall of the left atrium, and the second balloon 2b after inflation can extend into the inside of the pulmonary vein 8 from the opening of the pulmonary vein 8 due to the smaller outer diameter after inflation; the first balloon 2a after inflation and the second balloon 2b after inflation together form a gourd-shaped tissue icing area 4 at the target tissue position, and the ablation catheter 6 is wrapped around the outer periphery of the second balloon 2b. The dual-energy ablation catheter with the double balloons 2 has better cooling effect on the inner wall tissue at the opening of the pulmonary vein 8 where the ablation catheter 6 is located due to the closer position of the second balloon 2b, and the range of the inner wall tissue at the opening of the pulmonary vein 8 iced to form the tissue icing area 4 is larger, which is conducive to further improving the treatment effect of pulse ablation.

[0058] Embodiment Three

[0059] A dual-energy ablation catheter as shown in FIG. 8, which is different from the first and second embodiments in that there is no push tube 5 inside the inner tube 11 of the catheter body 1, and the plurality of ablation electrodes 3 are directly attached to the outer wall of the balloon 2, and the plurality of ablation electrodes 3 are electrically connected through wires and conductive structures inside the catheter body 1 and ultimately connected to the pulse generating device. After the balloon 2 is inflated, the target tissue is frozen and forms a tissue icing area 4, and the plurality of ablation electrodes 3 perform pulsed ablation on the target tissue in the tissue icing area 4 through pulsed current. This dual-energy ablation catheter does not need to set a push tube 5 inside the catheter body 1, directly uses the plurality of ablation electrodes 3 on the outer wall of the balloon 2 for pulsed effect, and can also achieve the treatment effect of pulsed ablation of pulsed current under the constraint of the tissue icing area 4 in the icing state, reducing the probability of complications during ablation treatment; but since part of the ablation electrodes 3 are not attached to the inner wall of the target tissue, the number of micro-holes formed by the ablation electrodes 3 on the target tissue is less, and the ablation treatment effect is relatively poor compared with the first and second embodiments.

[0060] Example Four

[0061] A dual-energy ablation catheter as shown in FIG. 9, which is different from the first and second embodiments in that the distal end of the push tube 5 is only connected to one ablation catheter 6, and the plurality of ablation electrodes 3 are annular electrodes spaced and sleeved on the outer periphery of the ablation catheter 6 along the length extension direction of the ablation catheter 6. The ablation catheter 6 has a storage state of being accommodated inside the inner tube 11 and a natural deployment state of extending outward from the distal end of the inner tube 11 under the pushing action of the push tube 5. The ablation catheter 6 is made of shape memory alloy, and when the ablation catheter 6 is in the natural deployment state, the ablation catheter 6 expands outward to form a ring shape, and the annular ablation catheter 6 is attached to the inner wall of the target tissue.

[0062] The double-energy ablation catheter provided by the embodiments of the present application provides a target point selective pulsed field ablation method enhanced and constrained by a tissue icing area. The electric field attenuates faster in the ice block, and the ice block is easy to constrain the electric field inside the ice block. The pulsed electric field generated in the pulsed ablation process is more likely to be constrained in the icing tissue. In the double-energy ablation treatment process, the target tissue is first frozen by the refrigerant in the balloon 2, and the icing tissue area 4 in the icing state is quickly formed on the target tissue. Then, the target tissue in the icing tissue area 4 is subjected to pulsed discharge by the ablation electrode 3. The pulsed electric field ablates the selected target tissue in the icing tissue area 4. Under the constraint of the icing tissue area 4 in the icing state, the energy of the pulsed current generated by the ablation electrode 3 is more constrained in the icing tissue area 4 and its adjacent area (it should be noted that the range of the pulsed field ablation includes not only the above-mentioned part of the target tissue in the icing tissue area, but also the part of the target tissue in the adjacent area outside the icing tissue area). Therefore, the energy of the pulsed current is less likely to leak to other tissues or cells (including blood) outside the target tissue to be ablated, which can reduce the damage of the pulsed current to the non-target tissue, thereby reducing the probability of complications such as hemolysis, micro-bubbles, and coronary artery spasm in the blood during the ablation treatment, and improving the effectiveness and safety of the pulsed ablation. Under the action of the pulsed electric field, the effective area of the traditional cryoablation is expanded from the-20°C or-40°C boundary to the entire icing tissue area 4, realizing the organic combination of cryoablation and pulsed field ablation. Compared with the ablation treatment method of alternating cryoablation and pulsed field ablation, the ablation treatment effect is better. More importantly, the target point selective pulsed field ablation enhanced and constrained by the icing tissue area 4 can be used as a new solution for treating other tissues and cells, such as lung tumors.

[0063] In some embodiments, the double-energy ablation catheter can also be configured for use in non-cardiac surgical scenarios, including targeted ablation of lung tumors or focal brain lesions. The balloon structure therein can be shaped to conform to irregular or patient-specific anatomical targets, enabling customization of cryoconfinement and pulsed electric field delivery, and thus enabling precise, personalized treatment.

[0064] The advantage of this double-energy ablation treatment method is that when applied to smaller target points and / or smaller energy delivery catheters, the ablation treatment effect can be more obvious, for example, for brain ablation. In addition, the icing tissue area 4 can be irregular, and different shapes of icing tissue areas 4 can be formed by combining different shapes of balloons 2 or cryoablation needles, to treat different shapes of disease targets and achieve patient-specific customized treatment.

[0065] The application also provides a dual-energy ablation method based on a dual-energy ablation catheter, which is essentially a target tissue pulse field ablation treatment method enhanced and constrained by a freezing field.

[0066] Step S1: delivering the dual-energy ablation catheter to a region where the target tissue is located.

[0067] The dual-energy ablation catheter includes a catheter body 1 and an expandable element and a plurality of ablation electrodes 3 arranged at the distal end of the catheter body 1. The dual-energy ablation catheter is specifically any one of the four embodiments described above.

[0068] Step S2: inputting a coolant into the lumen of the expandable element through the catheter body 1, and the lumen of the expandable element expands outward after the coolant is inputted, and the expanded expandable element freezes the target tissue and forms a tissue freezing region 4 in a frozen state on the target tissue.

[0069] Specifically, the tissue freezing region 4 in the frozen state includes a tissue cryoablation region surrounding the outer periphery of the expanded expandable element and a tissue cryofreezing region outside the tissue cryoablation region; wherein the temperature of the tissue cryoablation region is lower than the temperature of the tissue cryofreezing region. For example, the temperature of the tissue cryoablation region is equal to or less than -20℃, and the temperature of the tissue cryofreezing region is equal to or less than 0℃ but greater than the temperature of the tissue cryoablation region. The damage degree of the target tissue in the tissue cryoablation region under the action of low-temperature freezing is higher than the damage degree of the target tissue in the tissue cryofreezing region under the action of low-temperature freezing.

[0070] Preferably, the coolant is liquid ethanol with a temperature lower than -40℃.

[0071] Step S3: the plurality of ablation electrodes 3 are attached to the tissue freezing region 4 in the frozen state, and the plurality of ablation electrodes 3 release electric pulses through the ice in the tissue freezing region 4 to perform pulse field ablation on the target tissue.

[0072] Specifically, since the damage degree of the partial target tissue in the tissue frozen ice region is small during the freezing process, the freezing ablation effect is poor; the multiple ablation electrodes 3 are used to perform pulse discharge on the target tissue in the tissue ice region 4, the electric pulse released by the ablation electrode 3 performs pulse field ablation on the selected target tissue under the constraint of the ice in the tissue ice region 4, especially the target tissue in the tissue frozen ice region with small freezing damage degree, the damage degree of the target tissue in the tissue frozen ice region is further increased after pulse ablation, the ablation effect of the target tissue in this part of the ice region is improved, the effective area of the traditional freezing ablation can be expanded from the boundary of-20℃ or-40℃ to the boundary of the entire tissue ice region below 0℃, the organic combination of freezing ablation and pulse field ablation is realized, and the ablation treatment effect is better than that of the ablation treatment mode of alternating freezing ablation and pulse field ablation.

[0073] Obviously, the above embodiments are only examples for clearly illustrating, but not limitation to the embodiments. Other different forms of changes or variations can be made on the basis of the above description for those skilled in the art. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A dual-energy ablation catheter, comprising: The catheter body (1) comprises an inner tube (11) and an outer tube (12), the inner tube (11) passes through the inside of the outer tube (12), the balloon (2) is connected to the outer wall of the outer tube (12), a medium conveying channel is formed between the inner tube (11) and the outer tube (12), and a through hole (121) for connecting the medium conveying channel and the inner cavity of the balloon (2) is arranged on the tube wall of the outer tube (12).

2. The dual-energy ablation catheter of claim 1, wherein, Further comprising a push tube (5) which is slidingly arranged inside the catheter body (1), an ablation catheter (6) is connected to the end of the distal end of the push tube (5), and the ablation electrodes (3) are arranged on the ablation catheter (6); under the pushing action of the push tube (5), the ablation catheter (6) has a storage state of being accommodated inside the catheter body (1) and a natural unfolding state of extending outward from the distal end of the catheter body (1) and unfolding outward.

3. The dual-energy ablation catheter of claim 1, wherein, The ablation catheter (6) also has a taut state of bending towards the peripheral direction of the balloon (2) under the action of external force; when the ablation catheter (6) is in the taut state, the ablation electrodes (3) on the ablation catheter (6) are in close contact with the target tissue of the tissue icing area (4) and its adjacent area to perform pulse ablation on the target tissue.

4. The dual-energy ablation catheter of claim 3, wherein, The ablation catheter (6) is made of shape memory alloy.

5. The dual-energy ablation catheter of claim 3, wherein, The ablation catheter (6) comprises a proximal catheter segment (61) and a distal catheter segment (62), one end of the proximal catheter segment (61) is connected to the distal end of the push tube (5), and the distal catheter segment (62) is connected to the other end of the proximal catheter segment (61); when the ablation catheter (6) is in the natural unfolding state, the distal catheter segment (62) bends relative to the proximal catheter segment (61) towards the direction deviating from the axis of the push tube (5); a plurality of ablation electrodes (3) are arranged on the distal catheter segment (62).

6. The dual-energy ablation catheter of claim 4, wherein, The proximal catheter segment (61) is connected with a pull wire (7), the other end of the pull wire (7) is connected to an operating handle, and the operating handle drives the ablation catheter (6) to bend towards the balloon (2) through the pull wire (7).

7. The dual-energy ablation catheter of claim 6, wherein, The ablation catheter (6) has a plurality of ablation electrodes (3) which are uniformly and spacedly arranged along the length direction of the distal catheter segment (62); when the ablation catheter (6) is in the taut state, a plurality of the ablation catheters (6) are uniformly and spacedly arranged around the circumference of the balloon (2).

8. The dual-energy ablation catheter of claim 6, wherein, ​ 9. The dual-energy ablation catheter of claim 4, wherein, The balloon (2) comprises a first balloon (2a) and a second balloon (2b) which can be inflated by the coolant, the second balloon (2b) is located at the distal end of the first balloon (2a), the outer diameter of the first balloon (2a) after inflation is larger than the outer diameter of the second balloon (2b) after inflation; when the ablation catheter (6) is in the taut state, the ablation catheter (6) is wrapped around the outer periphery of the second balloon (2b).

10. The dual-energy ablation catheter of claim 5, wherein, When the ablation catheter (6) is in the natural expansion state, the ablation catheter (6) expands outward to form a ring shape, and the ablation electrode (3) is a ring electrode which is spaced and sleeved on the outer periphery of the ablation catheter (6) along the extension direction of the ring of the ablation catheter (6).

11. The dual-energy ablation catheter of claim 1, wherein, The coolant input into the expandable element is liquid ethanol with a temperature lower than -40℃.

12. The dual-energy ablation catheter of claim 1, wherein, A plurality of ablation electrodes (3) are attached to the outer wall of the expandable element, and a plurality of ablation electrodes (3) are attached to the outer wall of the tissue icing area (4) along with the expansion of the expandable element to perform pulsed ablation on the target tissue of the tissue icing area (4) and its adjacent area.

13. A dual-energy ablation method based on a dual-energy ablation catheter, characterized in that, The method comprises the following steps: A double-energy ablation catheter is delivered to the area where the target tissue is located; wherein the double-energy ablation catheter comprises a catheter body and an expandable element and a plurality of ablation electrodes arranged at the distal end of the catheter body, wherein the expandable element is a balloon (2); A coolant is input into the lumen of the expandable element through the catheter body, and the lumen of the expandable element expands outward after the coolant is input, and the expanded expandable element freezes the target tissue and forms a tissue icing area in an icing state on the target tissue; A plurality of ablation electrodes are attached to the tissue icing area in an icing state, and a plurality of ablation electrodes release electric pulses through the ice in the tissue icing area to perform pulsed field ablation on the target tissue.

14. The dual-energy ablation method based on a dual-energy ablation catheter of claim 13, characterized in that, The tissue icing area in an icing state comprises a tissue cryoablation area surrounding the outer periphery of the expanded expandable element and a tissue cryoicing area outside the tissue cryoablation area; wherein the temperature of the tissue cryoablation area is lower than the temperature of the tissue cryoicing area, and the damage degree of the target tissue in the tissue cryoicing area under the action of low-temperature freezing is higher than the damage degree of the target tissue in the tissue cryoicing area under the action of low-temperature freezing; The electric pulses released by a plurality of ablation electrodes perform pulsed field ablation on the target tissue of the tissue cryoicing area and its adjacent area under the constraint of the ice in the tissue icing area, so as to improve the damage degree of the target tissue of the tissue cryoicing area and its adjacent area.

15. The dual-energy ablation method based on a dual-energy ablation catheter of claim 14, wherein, The temperature of the tissue cryoablation area is equal to or less than -20℃, and the temperature of the tissue cryoicing area is equal to or less than 0℃.

16. The dual-energy ablation method based on a dual-energy ablation catheter of claim 13, wherein, The coolant input into the expandable element is liquid ethanol with a temperature lower than -40℃.

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