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

Abstract

The invention discloses 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 body, an expandable element and an ablation electrode, wherein the expandable element and the ablation electrode are arranged at the far end of the catheter body. The expandable element is suitable for expanding outwards after a secondary refrigerant is introduced into an inner cavity of the expandable element and freezing on a target tissue to form a tissue icing area in an icing state, and the ablation electrode is suitable for performing pulse ablation on the target tissue in the tissue icing area. The method comprises the following steps: freezing a target tissue by using an expandable element to form a tissue icing area in an icing state, and performing pulse discharge on the target tissue in the tissue icing area by using an ablation electrode; due to the fact that the pulse current can be restrained by the icing object in the tissue icing area, more energy of the pulse current can be restrained in the tissue icing area, energy leakage of the pulse current is less, damage of the pulse current to non-target tissue can be reduced, and effectiveness and safety of pulse ablation are improved.

Description

Technical Field

[0001] This invention relates to the field of interventional medical device technology, specifically to a dual-energy ablation catheter and a dual-energy ablation method based on the dual-energy ablation catheter. Background Technology

[0002] Atrial fibrillation (AF) is a common cardiac arrhythmia characterized by irregular and rapid electrical signals in the atria (the upper chambers of the heart). These abnormal signals can lead to reduced blood pumping, potentially causing symptoms such as palpitations, fatigue, and shortness of breath. Studies have shown that catheter ablation can successfully electrically isolate the pulmonary veins, effectively preventing the recurrence of AF and serving as an effective means for AF patients to restore and maintain sinus rhythm.

[0003] Traditionally, radiofrequency (RF) ablation using catheters has been the standard treatment for atrial fibrillation. RF ablation works by converting electrical current flowing through the target tissue into heat energy due to the tissue's impedance. This heat energy is then conducted and slightly radiated to adjacent tissues, causing small-scale tissue damage—a process known as point-by-point ablation. This point-by-point ablation ultimately achieves segmental or circumferential electrical isolation of the pulmonary veins, forming complete electrical isolation between the pulmonary veins and the left atrium, known as PVI. This technique is relatively difficult to perform, has a long ablation time, a long learning curve, and requires highly skilled operators. Patients experience significant pain during the procedure. Furthermore, in some patients, RF ablation of the pulmonary veins fails to create transmural damage, easily leading to pulmonary vein leakage and atrial fibrillation recurrence.

[0004] 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 complications from cryoablation (such as phrenic nerve injury and atrial-esophageal fistula) can still be as high as 5%, and some complications can have serious consequences. Pulsed field ablation, also known as FPA, is a non-thermal tissue ablation technique that uses a high-amplitude pulsed electric field to create irreversible electroporation in tissues, causing cell apoptosis and achieving non-thermal ablation. Pulsed field ablation has no effect on the esophagus and diaphragm, so compared to cryoablation, it has a lower risk of complications such as phrenic nerve injury and atrial-esophageal fistula. However, during pulsed field ablation, some of the energy generated by the electrodes can easily leak into the surrounding tissues or cells (including blood), which can easily cause new symptoms different from traditional cryoablation, such as hemolysis, microbubbles, and coronary artery spasm, resulting in lower safety.

[0005] Therefore, there is a need to develop a new ablation catheter that offers better ablation treatment results, fewer complications, and higher safety. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of existing cryoablation and pulsed field ablation in the treatment of atrial fibrillation, which have poor treatment effects and high risk of complications, and thus provide a dual ablation catheter and a dual-energy ablation method based on the dual-energy ablation catheter.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] A dual-energy ablation catheter includes a catheter body, an expandable element disposed at the distal end of the catheter body, and a plurality of ablation electrodes. The expandable element is adapted to expand outward after a refrigerant is introduced into its lumen. The expanded expandable element is adapted to freeze the target tissue and form a frozen tissue region on the target tissue. The plurality of ablation electrodes are adapted to perform pulse ablation on the target tissue within the frozen tissue region.

[0009] Furthermore, the expandable element is a balloon.

[0010] Furthermore, the catheter body includes an inner tube and an outer tube, the inner tube passes through the inside of the outer tube, the balloon is connected to the outer wall of the outer tube, a medium delivery channel is formed between the inner tube and the outer tube, and the outer tube wall is provided with a through hole communicating with the medium delivery channel and the inner cavity of the balloon.

[0011] Furthermore, it also includes a push tube, which is slidably disposed inside the catheter body. The distal end of the push tube is connected to an ablation catheter, and the ablation electrode is disposed on the ablation catheter. Under the pushing action of the push tube, the ablation catheter has a contained state that is housed inside the catheter body, and a naturally extended state that extends outward from the distal end of the catheter body.

[0012] Furthermore, the ablation catheter is also in a taut state where it bends towards the periphery of the balloon under external force; when the ablation catheter is in the taut state, the ablation electrode on the ablation catheter is in contact with the target tissue in the tissue freezing area to perform pulse ablation on the target tissue.

[0013] Furthermore, the ablation catheter is made of shape memory alloy.

[0014] Furthermore, the ablation catheter includes a proximal catheter segment and a distal catheter segment, one end of the proximal catheter segment is connected to the distal end of the push tube, and the distal catheter segment is connected to the other end of the proximal catheter segment; when the ablation catheter is in the naturally extended state, the distal catheter segment bends relative to the proximal catheter segment in a direction deviating from the axis of the push tube; a plurality of ablation electrodes are disposed on the distal catheter segment.

[0015] Furthermore, the proximal catheter segment is connected to a pull wire, the other end of which is connected to an operating handle. The operating handle drives the ablation catheter to bend closer to the balloon via the pull wire.

[0016] Furthermore, the ablation catheter has multiple ablation electrodes that are evenly spaced along the length of the distal catheter segment; when the ablation catheter is in the taut state, the multiple ablation catheters are evenly spaced around the balloon in the circumferential direction.

[0017] Furthermore, the balloon includes a first balloon and a second balloon that can expand after a refrigerant is introduced, the second balloon being located at the distal end of the first balloon, and the outer diameter of the first balloon being larger than the outer diameter of the second balloon; when the ablation catheter is in the taut state, the ablation catheter surrounds the outer periphery of the second balloon.

[0018] Furthermore, when the ablation catheter is in a naturally extended state extending outward from the distal end of the catheter body, the ablation catheter is annular, and the plurality of ablation electrodes are annular electrodes spaced apart and sleeved on the outer periphery of the ablation catheter along the extension direction of the ablation catheter.

[0019] Furthermore, the coolant input into the expandable element is liquid ethanol with a temperature below -40°C.

[0020] Furthermore, a plurality of ablation electrodes are attached to the outer wall of the expandable element, and the plurality of ablation electrodes adhere to the outer wall of the tissue freezing area (4) as the expandable element expands to perform pulse ablation on the target tissue within the tissue freezing area.

[0021] This invention also provides a dual-energy ablation method based on a dual-energy ablation catheter, comprising the following steps:

[0022] A dual-energy ablation catheter is delivered to the area where the target tissue is located; wherein the dual-energy ablation catheter includes a catheter body and an expandable element and multiple ablation electrodes disposed at the distal end of the catheter body;

[0023] A refrigerant is introduced into the lumen of the expandable element through the catheter body. After the refrigerant is introduced, the lumen of the expandable element expands outward. The expanded expandable element freezes the target tissue and forms a frozen tissue area on the target tissue.

[0024] Multiple ablation electrodes are attached to the frozen area of ​​the tissue in a frozen state, and the multiple ablation electrodes release electrical pulses through the frozen material in the frozen area of ​​the tissue to perform pulse field ablation on the target tissue.

[0025] Furthermore, the frozen tissue region in the frozen state includes a tissue cryoablation region surrounding the expanded expandable element and a tissue cryo-icing region located outside the tissue ablation region; wherein, the temperature of the tissue cryoablation region is lower than the temperature of the tissue cryo-icing region, and the degree of damage to the target tissue in the tissue cryoablation region under low-temperature freezing is higher than the degree of damage to the target tissue in the tissue cryo-icing region under low-temperature freezing.

[0026] The electrical pulses released by the multiple ablation electrodes perform pulsed field ablation on the target tissue within the frozen tissue region under the constraint of the icing material, thereby increasing the degree of damage to the target tissue within the frozen tissue region.

[0027] Furthermore, the temperature of the tissue cryoablation zone is equal to or less than -20°C, and the temperature of the tissue cryofreezing zone is equal to or less than 0°C.

[0028] Furthermore, the coolant input into the expandable element is liquid ethanol with a temperature below -40°C.

[0029] The dual-energy ablation catheter provided by this invention utilizes the properties that electric fields attenuate faster within ice, that the potential difference of the electric field is greater within ice, and that ice easily confines the electric field within the ice. During ablation treatment, the target tissue is first frozen using a cryogenic medium within the balloon, rapidly forming a frozen area. Within this frozen area, the portion of the target tissue relatively close to the expandable element has a relatively low temperature (typically below -20°C or -40°C), resulting in greater damage during freezing and better cryoablation effect. Conversely, another portion of the target tissue relatively far from the expandable element within the frozen area has a relatively high temperature (typically below 0°C), resulting in greater damage during freezing and better cryoablation effect. The damage during freezing is small, resulting in poor cryoablation effects. Subsequently, multiple ablation electrodes are used to pulse-discharge the target tissue within the frozen area. The pulsed electric field ablates the selected target tissue within the frozen area, particularly increasing the damage to the relatively low-temperature, less-damaged parts of the frozen tissue after pulse ablation, thus improving the ablation effect on these parts. This expands the effective area of ​​traditional cryoablation from the boundary of -20℃ or -40℃ to the boundary of the entire frozen tissue area below 0℃, achieving an organic combination of cryoablation and pulsed field ablation. Compared to ablation treatment methods that alternate between cryoablation and pulsed field ablation, this method yields better ablation treatment results. Furthermore, because the pulsed current is constrained by the frozen area of ​​the tissue, the energy of the pulsed current generated by the ablation electrode is largely confined within this frozen region. Therefore, less energy leaks out to other tissues or cells (including blood) outside the frozen area, reducing damage to non-target tissues. This decreases the probability of complications such as hemolysis, microbubbles, and coronary artery spasm during ablation treatment, improving the effectiveness and safety of pulsed ablation. In addition, the greater potential difference of the pulsed electric field within the ice further enhances the pulsed ablation effect on the target tissue. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the dual-energy ablation catheter used for ablation treatment of pulmonary veins in Embodiment 1 of the present invention;

[0032] Figure 2This is a schematic diagram of the structure of the dual-energy ablation catheter in Embodiment 1 of the present invention, when the balloon is inflated and the ablation catheter is in a contained state.

[0033] Figure 3 This is a schematic diagram of the structure of the dual-energy ablation catheter in Embodiment 1 of the present invention, when the balloon is inflated and the ablation catheter is in a naturally deployed state.

[0034] Figure 4 for Figure 3 The right view;

[0035] Figure 5 This is a schematic diagram of the structure of the dual-energy ablation catheter in Embodiment 1 of the present invention, when the balloon is inflated and the ablation catheter is taut.

[0036] Figure 6 for Figure 5 The right view;

[0037] Figure 7 This is a schematic diagram of the structure of the dual-energy ablation catheter used for ablation treatment of pulmonary veins in Embodiment 2 of the present invention;

[0038] Figure 8 This is a schematic diagram of the structure of the dual-energy ablation catheter used for ablation treatment of pulmonary veins in Embodiment 3 of the present invention;

[0039] Figure 9 This is a schematic diagram of the structure of the dual-energy ablation catheter used for ablation treatment of pulmonary veins in Embodiment 4 of the present invention.

[0040] Explanation of reference numerals in the attached diagram: 1. Catheter body; 11. Inner tube; 12. Outer tube; 121. Through hole; 2. Balloon; 2a. First balloon; 2b. Second balloon; 3. Ablation electrode; 4. Tissue freezing area; 5. Push tube; 6. Ablation catheter; 61. Proximal catheter segment; 62. Distal catheter segment; 7. Pull suture; 8. Pulmonary vein. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this application, it should be understood that the terms "proximal" and "distal" throughout refer to near and far relative to the operator. In use, the end closer to the doctor or operator is the "proximal" end, i.e., the end where the operator is located, and the end farther from the doctor or operator is the "distal" end, i.e., the end where the balloon is located. The above descriptions of orientation are for ease of description and simplification only, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application.

[0043] Example 1

[0044] like Figure 1 Figure 6 illustrates a dual-energy ablation catheter, comprising a catheter body 1, an expandable element, an ablation catheter 6, and multiple ablation electrodes 3. The distal end of the catheter body 1 is adapted to pass through a blood vessel or other tissue channel within the organism to reach the target tissue, and the proximal end of the catheter body 1 is connected to an operating handle. In this embodiment, the expandable element is specifically a balloon 2, and the balloon 2 and the ablation catheter 6 are disposed on the catheter body 1, with multiple ablation electrodes 3 disposed on the ablation catheter 6.

[0045] 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 sealed to the outer wall of the distal end of the outer tube 12. A medium delivery channel is formed between the inner tube 11 and the outer tube 12. The wall of the outer tube 12 has a through hole 121 that connects the medium delivery channel and the inner cavity of the balloon 2. External refrigerant can flow into the inner cavity of the balloon 2 through the medium delivery channel and the through hole 121. After the refrigerant is introduced, the balloon 2 expands outward. The expanded balloon 2 can freeze the target tissue and quickly form a frozen tissue area 4 (e.g., 100°C) on the target tissue. Figure 1 (At the opening where the middle pulmonary vein 8 connects to the left atrium). Multiple ablation electrodes 3 are connected to an external pulse generator, which provides electrical pulses to the ablation electrodes 3 to perform pulse ablation on the target tissue within the tissue icing area 4.

[0046] In some embodiments, the catheter body 1 further includes a push tube 5, which is slidably disposed inside the inner tube 11. An 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. The operating handle can control the push tube 5 to slide within the inner tube 11, causing the ablation catheter 6 to retract into the inner tube 11 or extend outward from the distal end of the inner tube 11. The ablation electrode 3 is electrically connected to an external pulse generator through a conductive structure within the push tube 5. Under the pushing action of the push tube 5, the ablation catheter 6 has a contained state within the inner tube 11 and a naturally extended state extending outward from the distal end of the inner tube 11; the ablation catheter 6 also has a taut state where it bends towards the periphery of the balloon 2 under external force. During ablation treatment, after the balloon 2 expands, it adheres to the inner wall of the target tissue (e.g., Figure 1 The balloon 2 adheres to the inner wall of the left atrium to freeze the target tissue. The target tissue (including the pulmonary vein 8 and blood in the left atrium) around the balloon 2 rapidly freezes into an ice ball at low temperature. The ablation catheter 6, constrained by the inner wall of the pulmonary vein 8, rests against it. At this time, the ablation catheter 6 is taut, and the ablation electrode 3 on the ablation catheter 6 is in contact with the inner wall of the pulmonary vein 8. The ablation electrode 3 can perform pulsed ablation on the inner wall tissue of the pulmonary vein 8 within the frozen tissue area 4 through a pulsed electric field. Because the ablation catheter 6 is taut, the ablation electrode 3 on the ablation catheter 6 can maintain closer contact with the inner wall tissue of the pulmonary vein 8, improving the pulsed ablation effect. After ablation, the push tube 5 can be retracted, and the ablation catheter 6 returns to the inner tube 11.

[0047] In some embodiments, the ablation catheter 6 is made of shape memory alloy. When the ablation catheter 6 extends from the end of the inner tube 11, it unfolds outwards due to its shape memory function, causing the distal end of the ablation catheter 6 to tilt away from the axis of the catheter body 1, thus preventing the distal end of the ablation catheter 6 from puncturing the target tissue. Specifically, the ablation catheter 6 includes an integrally formed 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 its naturally unfolded state, the distal catheter segment 62 bends relative to the proximal catheter segment 61 in a direction away from the axis of the push tube 5. Multiple ablation electrodes 3 are disposed on the distal catheter segment 62 and are evenly spaced along the length of the distal catheter segment 62. Multiple ablation catheters 6 are present, and when all multiple ablation catheters 6 are in a taut state, they are evenly spaced around the circumference of the balloon 2.

[0048] In some embodiments, the proximal catheter segment 61 is connected to a pull wire 7, the other end of which is connected to an operating handle. The operating handle, via the pull wire 7, causes the ablation catheter 6 to bend towards the balloon 2. The pull wire 7 facilitates pulling the ablation catheter 6 from its naturally extended state to a taut state. The taut ablation catheter 6 can better conform to the target tissue, improving the pulse ablation effect of the ablation electrode 3 on the ablation catheter 6 at the target tissue location.

[0049] In some embodiments, the refrigerant introduced into the balloon 2 is liquid ethanol with a temperature below -40°C. Traditionally, the refrigerant in the balloon 2 is a low-temperature gaseous refrigerant, such as nitrogen or nitrous oxide; the cooling capacity per unit volume of gaseous refrigerant is relatively small, and leakage at the connection point of the balloon 2 can cause serious damage to the human nervous system. In contrast, liquid ethanol has a large cooling capacity per unit volume, which not only allows the tissue around the balloon 2 to freeze rapidly, forming a tissue freezing area 4, but also makes leakage less likely; even if a small amount of leakage occurs, the harm to the human body is relatively small.

[0050] The dual-energy ablation catheter provided in this embodiment utilizes the properties that the electric field attenuates faster within ice, the electric field has a greater potential difference within ice, and ice easily confines the electric field within the ice. During ablation treatment, the target tissue is first frozen using the cryogenic fluid inside the balloon 2, rapidly forming a frozen tissue region 4. Within this frozen tissue region 4, the portion of the target tissue relatively close to the balloon 2 has a relatively low temperature (typically below -20°C or -40°C), resulting in greater damage during freezing and a better cryoablation effect. Conversely, another portion of the target tissue within the frozen tissue region 4, relatively far from the balloon 2, has a relatively high temperature (typically below 0°C), resulting in less damage during freezing and a less effective cryoablation. Subsequently, multiple ablation electrodes are used... 3. Pulsed discharge is applied to the target tissue within the frozen tissue region 4. The pulsed electric field ablates the selected target tissue within the frozen tissue region 4. In particular, the damage to the target tissue with relatively low temperature and minimal damage during the freezing process is further increased after pulse ablation, thus improving the ablation effect of this part of the target tissue. This expands the effective area of ​​traditional cryoablation from the boundary of -20℃ or -40℃ to the boundary of the entire frozen tissue region below 0℃, achieving an organic combination of cryoablation and pulsed field ablation. Compared with the ablation treatment method that alternates between cryoablation and pulsed field ablation, its ablation treatment effect is better. Furthermore, because the pulsed current is constrained by the frozen tissue region 4, the energy of the pulsed current generated by the ablation electrode 3 is largely confined within the frozen tissue region 4. Therefore, less energy leaks from the pulsed current into other tissues or cells (including blood) outside the frozen tissue region 4, reducing damage to non-target tissues. This decreases the probability of complications such as hemolysis, microbubbles, and coronary artery spasm during ablation treatment, improving the effectiveness and safety of pulsed ablation. In addition, the greater potential difference of the pulsed electric field within the ice further enhances the pulsed ablation effect on the target tissue.

[0051] Furthermore, this embodiment utilizes an expandable balloon 2 to cool the target tissue, and then uses an ablation catheter 6 with an ablation electrode 3 to perform pulse ablation on the target tissue in a dual-energy pulse ablation method. Compared with the prior art method of using a ring catheter to cool the target tissue and then using multiple electrodes arranged on the ring catheter to perform pulse ablation on the target tissue, the ablation electrode 3 in this embodiment is easier to attach to the target site of the target tissue for pulse ablation, resulting in better effectiveness. The electrode design is also simpler, and it avoids the problem that the ring catheter may be too large to effectively obtain accurate electrograms of the inner wall tissue at the opening of the pulmonary vein 8 through the electrodes.

[0052] To ensure that the ablation electrode 3 performs pulse ablation after the target tissue has frozen into an ice zone 4, the difference in ultrasonic signals between the target tissue before and after freezing is utilized. Ultrasonic testing of the target tissue can be used to determine whether it has frozen into an ice zone 4. When the ultrasonic test indicates that the target tissue has frozen into an ice zone 4, a pulse current is then supplied to the ablation electrode 3 for pulse ablation. Alternatively, the determination of whether the target tissue has frozen into an ice zone 4 can be achieved by controlling the input dosage (time, flow rate, power, etc.) of the refrigerant, or by measuring physical quantities such as the resistance of the target tissue.

[0053] Example 2

[0054] like Figure 7 The dual-energy ablation catheter shown differs from Embodiment 1 in that the balloon 2 on the catheter body 1 includes a first balloon 2a and a second balloon 2b that can expand after the introduction of a 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 expansion is larger than the outer diameter of the second balloon 2b after expansion. The second balloon 2b is adapted to fit against the inner wall of the left atrium after expansion. Due to its smaller outer diameter after expansion, the second balloon 2b can extend into the interior of the pulmonary vein 8 through the opening of the pulmonary vein 8. The expanded first balloon 2a and the expanded second balloon 2b together form a gourd-shaped tissue freezing area 4 at the target tissue location. The ablation catheter 6 surrounds the outer periphery of the second balloon 2b. This dual-energy ablation catheter with two balloons 2 has a better freezing effect on the inner wall tissue of the pulmonary vein 8 opening that is adjacent to the ablation catheter 6 because the second balloon 2b can be closer to the location of the ablation catheter 6. The area of ​​tissue freezing 4 formed by the freezing of the inner wall tissue of the pulmonary vein 8 opening is larger, which is conducive to further improving the therapeutic effect of pulse ablation.

[0055] Example 3

[0056] like Figure 8The dual-energy ablation catheter shown differs from Embodiments 1 and 2 in that the inner tube 11 of the catheter body 1 does not contain a push tube 5. Multiple ablation electrodes 3 are directly attached to the outer wall of the balloon 2. These electrodes are electrically connected to a conductive structure inside the catheter body 1 via wires and ultimately to a pulse generator. After the balloon 2 inflates, the target tissue freezes, forming a tissue freezing region 4. The multiple ablation electrodes 3 then perform pulse ablation on the target tissue within the tissue freezing region 4 using pulsed current. This dual-energy ablation catheter eliminates the need for a push tube 5 inside the catheter body 1, directly utilizing the multiple ablation electrodes 3 on the outer wall of the balloon 2 for a pulsed effect. It also achieves the therapeutic effect of pulsed ablation under the constraint of the frozen tissue freezing region 4, reducing the probability of complications during ablation treatment. However, because some ablation electrodes 3 are not adhered to the inner wall of the target tissue, fewer micropores are formed on the target tissue, resulting in a relatively poorer ablation treatment effect compared to the schemes in Embodiments 1 and 2.

[0057] Example 4

[0058] like Figure 9 The dual-energy ablation catheter shown differs from Embodiments 1 and 2 in that only one ablation catheter 6 is connected to the distal end of the push tube 5, and multiple ablation electrodes 3 are annular electrodes spaced along the length extension direction of the ablation catheter 6 on its outer periphery. Under the pushing action of the push tube 5, the ablation catheter 6 has a contained state inside the inner tube 11 and a naturally extended state extending outward from the distal end of the inner tube 11. The ablation catheter 6 is made of shape memory alloy. When the ablation catheter 6 is in its naturally extended state, it expands outward into an annular shape, and the annular ablation catheter 6 adheres to the inner wall of the target tissue.

[0059] The dual-energy ablation catheter provided in this invention offers a target-selective pulsed field ablation method enhanced and constrained by a tissue freezing region. Utilizing the property that electric fields attenuate faster within ice and that ice easily confines the electric field within the ice, the pulsed electric field generated during pulsed ablation is more easily confined within the frozen ice. During dual-energy ablation treatment, the target tissue is first frozen using a cryogenic medium within the balloon 2, rapidly forming a frozen tissue region 4. Then, the ablation electrode 3 performs pulsed discharge on the target tissue within the frozen tissue region 4. The pulsed electric field ablates the selected target tissue within the frozen tissue region 4. Under the constraint of the frozen tissue region 4, the energy of the pulsed current generated by the ablation electrode 3 is largely confined within this region. Therefore, less energy leaks out to other tissues or cells (including blood) outside the frozen tissue region 4, reducing damage to non-target tissues and thus decreasing the probability of complications such as hemolysis, microbubbles, and coronary artery spasm during ablation treatment. This improves the effectiveness and safety of pulsed ablation. Under the influence of the pulsed electric field, the effective area of ​​traditional cryoablation (-20℃ or -40℃) can be expanded to the entire frozen tissue region 4, achieving an organic combination of cryoablation and pulsed field ablation. Compared to ablation treatments that alternate between cryoablation and pulsed field ablation, this method yields better therapeutic effects. More importantly, this target-selective pulsed field ablation enhanced and constrained by the frozen tissue region 4 can serve as a novel solution for treating other tissues and cells, such as lung tumors. The advantage of this dual-energy ablation therapy is that the ablation effect may be more pronounced when applied to smaller target sites and / or smaller energy delivery catheters, such as in brain ablation. Furthermore, the tissue freezing area 4 can be irregular; it can be formed by combining balloons 2 or cryoablation needles of different shapes to treat disease targets of different shapes, achieving patient-specific customized treatment.

[0060] This invention also provides a dual-energy ablation method based on a dual-energy ablation catheter. This dual-energy ablation method is essentially a targeted tissue pulsed field ablation treatment method enhanced and constrained by a frozen field. The method includes the following steps:

[0061] Step S1: Deliver the dual-energy ablation catheter to the area where the target tissue is located.

[0062] The dual-energy ablation catheter includes a catheter body 1, an expandable element disposed at the distal end of the catheter body 1, and multiple ablation electrodes 3. Specifically, the dual-energy ablation catheter can be any one of the four embodiments described above.

[0063] Step S2: A coolant is introduced into the inner lumen of the expandable element through the catheter body 1. After the coolant is introduced, the inner lumen of the expandable element expands outward. The expanded expandable element freezes the target tissue and forms a frozen tissue area 4 on the target tissue.

[0064] Specifically, the frozen tissue region 4 includes a tissue cryoablation region surrounding the expanded expandable element and a frozen tissue region located outside the tissue ablation region; wherein, the temperature of the tissue cryoablation region is lower than the temperature of the frozen tissue region. For example, the temperature of the tissue cryoablation region is equal to or less than -20°C, and the temperature of the frozen tissue region is equal to or less than 0°C but higher than the temperature of the tissue cryoablation region. The degree of damage to the target tissue within the tissue cryoablation region under low-temperature freezing is higher than the degree of damage to the target tissue within the frozen tissue region under low-temperature freezing.

[0065] The preferred refrigerant is liquid ethanol with a temperature below -40°C.

[0066] Step S3: Multiple ablation electrodes 3 are attached to the frozen area of ​​the tissue in a frozen state, and the multiple ablation electrodes 3 release electrical pulses through the frozen material in the frozen area 4 of the tissue to perform pulse field ablation on the target tissue.

[0067] Specifically, because some target tissues within the frozen tissue region suffer minimal damage during the freezing process, cryoablation is ineffective. By utilizing multiple ablation electrodes 3 to pulse-discharge the target tissues within the frozen tissue region 4, the electrical pulses released by the ablation electrodes 3, constrained by the icing material within the frozen tissue region 4, perform pulsed field ablation on the selected target tissues. This is particularly effective for target tissues within the frozen tissue region with minimal freezing damage, further increasing the degree of damage after pulsed ablation and improving the ablation effect in this frozen region. This expands the effective area of ​​traditional cryoablation from the boundary of -20℃ or -40℃ to the boundary of the entire frozen tissue region below 0℃, achieving an organic combination of cryoablation and pulsed field ablation. Compared to ablation treatment methods that alternate between cryoablation and pulsed field ablation, this method offers better ablation treatment results.

[0068] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dual-energy ablation catheter, characterized in that, The device includes a catheter body (1) and an expandable element and a plurality of ablation electrodes (3) disposed at the distal end of the catheter body (1). The expandable element is adapted to expand outward after a coolant is introduced into its lumen. The expanded expandable element is adapted to freeze the target tissue and form a frozen tissue region (4) on the target tissue. The plurality of ablation electrodes (3) are adapted to perform pulse ablation on the target tissue within the frozen tissue region (4).

2. The dual-energy ablation catheter according to claim 1, characterized in that, The expandable element is a balloon (2).

3. The dual-energy ablation catheter according to claim 2, characterized in that, 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 connected to the outer wall of the outer tube (12). A medium delivery channel is formed between the inner tube (11) and the outer tube (12). The outer tube (12) has a through hole (121) on its wall that connects the medium delivery channel and the inner cavity of the balloon (2).

4. The dual-energy ablation catheter according to claim 2, characterized in that, It also includes a push tube (5), which is slidably disposed inside the catheter body (1). The distal end of the push tube (5) is connected to an ablation catheter (6), and the ablation electrode (3) is disposed on the ablation catheter (6). Under the pushing action of the push tube (5), the ablation catheter (6) has a containment state inside the catheter body (1) and a natural unfolding state extending outward from the distal end of the catheter body (1).

5. The dual-energy ablation catheter according to claim 4, characterized in that, The ablation catheter (6) is also in a taut state where it bends toward the outer periphery of the balloon (2) under the action of external force; when the ablation catheter (6) is in the taut state, the ablation electrode (3) on the ablation catheter (6) is attached to the target tissue in the tissue freezing area (4) to perform pulse ablation on the target tissue.

6. The dual-energy ablation catheter according to claim 4, characterized in that, The ablation catheter (6) is made of shape memory alloy.

7. The dual-energy ablation catheter according to claim 5, characterized in that, The ablation catheter (6) includes 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 naturally unfolded state, the distal catheter segment (62) bends relative to the proximal catheter segment (61) in a direction deviating from the axis of the push tube (5). A plurality of ablation electrodes (3) are disposed on the distal catheter segment (62).

8. The dual-energy ablation catheter according to claim 7, characterized in that, The proximal catheter segment (61) is connected to a pull wire (7), the other end of which is connected to an operating handle. The operating handle drives the ablation catheter (6) to bend toward the balloon (2) via the pull wire (7).

9. The dual-energy ablation catheter according to claim 7, characterized in that, The ablation catheter (6) has multiple ablation electrodes (3) that are evenly spaced along the length of the distal catheter segment (62). When the ablation catheter (6) is in the taut state, the multiple ablation catheters (6) are evenly spaced around the balloon (2).

10. The dual-energy ablation catheter according to claim 5, characterized in that, The balloon (2) includes a first balloon (2a) and a second balloon (2b) that can expand after a coolant is introduced. The second balloon (2b) is located at the distal end of the first balloon (2a). The outer diameter of the first balloon (2a) after expansion is larger than the outer diameter of the second balloon (2b) after expansion. When the ablation catheter (6) is in the taut state, the ablation catheter (6) surrounds the outer periphery of the second balloon (2b).

11. The dual-energy ablation catheter according to claim 6, characterized in that, When the ablation catheter (6) is in the naturally unfolded state, the ablation catheter (6) unfolds outward to form a ring, and the ablation electrode (3) is a ring electrode that is spaced around the outer periphery of the ablation catheter (6) along the loop extension direction of the ablation catheter (6).

12. The dual-energy ablation catheter according to claim 1, characterized in that, The coolant supplied to the expandable element is liquid ethanol with a temperature below -40°C.

13. The dual-energy ablation catheter according to claim 1, characterized in that, Multiple ablation electrodes (3) are attached to the outer wall of the expandable element. As the expandable element expands, the multiple ablation electrodes (3) adhere to the outer wall of the tissue freezing area (4) to perform pulse ablation on the target tissue within the tissue freezing area (4).

14. A dual-energy ablation method based on a dual-energy ablation catheter, characterized in that, Includes the following steps: A dual-energy ablation catheter is delivered to the area where the target tissue is located; wherein the dual-energy ablation catheter includes a catheter body and an expandable element and multiple ablation electrodes disposed at the distal end of the catheter body; A refrigerant is introduced into the lumen of the expandable element through the catheter body. After the refrigerant is introduced, the lumen of the expandable element expands outward. The expanded expandable element freezes the target tissue and forms a frozen tissue area on the target tissue. Multiple ablation electrodes are attached to the frozen area of ​​the tissue in a frozen state, and the multiple ablation electrodes release electrical pulses through the frozen material in the frozen area of ​​the tissue to perform pulse field ablation on the target tissue.

15. The dual-energy ablation method based on a dual-energy ablation catheter according to claim 14, characterized in that, The frozen tissue region includes a tissue cryoablation region surrounding the expanded expandable element and a tissue cryo-icing region located outside the tissue cryoablation region; wherein, the temperature of the tissue cryoablation region is lower than the temperature of the tissue cryo-icing region, and the degree of damage to the target tissue in the tissue cryoablation region under low-temperature freezing is higher than the degree of damage to the target tissue in the tissue cryo-icing region under low-temperature freezing. The electrical pulses released by the multiple ablation electrodes, constrained by the ice in the frozen area of ​​the tissue, perform pulsed field ablation on the target tissue within the frozen area, thereby increasing the degree of damage to the target tissue within the frozen area.

16. The dual-energy ablation method based on a dual-energy ablation catheter according to claim 15, characterized in that, The temperature of the tissue cryoablation zone is equal to or less than -20°C, and the temperature of the tissue cryofreezing zone is equal to or less than 0°C.

17. The dual-energy ablation method based on a dual-energy ablation catheter according to claim 14, characterized in that, The coolant supplied to the expandable element is liquid ethanol with a temperature below -40°C.

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