Radio-frequency ablation catheter, method for determining catheter-tissue fitting degree, and ablation system
Patent Information
- Application Number
- PCT/CN2026/081337
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-17
- Filing Date
- 2026-03-04
- Publication Date
- 2026-09-24
Smart Images
Figure CN2026081337_24092026_PF_FP_ABST
Abstract
Description
Radiofrequency ablation catheters, methods for determining catheter tissue fit, and ablation systems
[0001] Cross-references to related applications
[0002] This disclosure claims priority to Chinese Patent Application No. 2025103113298, filed on March 17, 2025, entitled "A Radiofrequency Ablation Catheter and a Method for Determining the Tissue Fit of the Catheter", the entire contents of which are incorporated herein by reference. Technical Field
[0003] This disclosure relates to the field of medical device technology, and more specifically, to a radiofrequency ablation catheter, a method for determining the tissue fit of the catheter, and an ablation system. Background Technology
[0004] For patients with type 2 diabetes and obesity, the most common treatments are medication and surgery. Medication for type 2 diabetes may not respond well to traditional drug therapy in some patients. Medication for obesity often causes adverse reactions, impacting patients' lives. Surgical treatments, such as gastric bypass surgery and sleeve gastrectomy, carry a high risk of surgical and postoperative complications and are generally expensive. Studies have shown that duodenal mucosal resurfacing (DMR), as a novel minimally invasive treatment, can effectively treat type 2 diabetes and obesity in certain cases, providing an option for many patients who do not respond well to traditional medications or are ineligible for traditional surgery. Currently, DMR products using hydrothermal, steam, and IRE methods have been disclosed. This application proposes an electrothermal ablation catheter configured for mucosal remodeling, aiming to perform DMR surgery via electrothermal means, providing patients with another treatment option. Of course, the same approach could also provide a treatment option for lesions in other natural body cavities.
[0005] Public content
[0006] The embodiments of this disclosure provide a radiofrequency ablation catheter, which guides the ablation electrode to the target location via a guidewire. The extended ablation electrode can ablate tissues in the duodenal cavity or other natural body cavities, providing a usable treatment option for patients with type 2 diabetes, obesity, or other cavity lesions. It also has the advantages of being minimally invasive, causing less patient pain, and having low surgical risk.
[0007] This disclosure also provides a method for determining the tissue fit of a catheter, which can avoid incomplete ablation caused by catheter body displacement. At the same time, based on the change in impedance value, it can determine whether the target tissue ablation is complete, so as to improve ablation efficiency and ensure ablation effect.
[0008] The embodiments of this disclosure can be implemented as follows:
[0009] The embodiments of this disclosure provide a radiofrequency ablation catheter, including a catheter body, a first cavity and a plurality of second cavities formed inside the catheter body, a balloon fixed to the outside of the catheter body, and at least one of the second cavities communicating with the inside of the balloon, and an ablation electrode assembled on the outside of the balloon.
[0010] In the initial state, both the balloon and the ablation electrode are in a contracted state. The ablation electrode is wound around the outside of the balloon in an involute shape, and the inner wall of the balloon is in contact with the outer wall of the catheter body. The working fluid is introduced into the balloon through the second cavity. The balloon and the ablation electrode simultaneously change from a contracted state to an extended state. After a high-frequency voltage is applied to the ablation electrode simultaneously, the capacitance to ground of the ablation electrode is calculated and the shape of the ablation electrode is determined.
[0011] Optionally, the ablation electrode is an interdigitated ablation electrode.
[0012] Optionally, the interdigitated ablation electrode includes a first substrate, a second substrate, multiple test electrodes, a first active electrode, a first loop electrode, and a first reset element. One end of the first substrate is fixed to the outside of the balloon, and the second substrate is fixed to the outside of the first substrate. The multiple test electrodes are arranged in a ring array between the first substrate and the second substrate, and the test electrodes and the first substrate, as well as the test electrodes and the second substrate, are fixedly connected. The first active electrode and the first loop electrode are arranged in an interdigitated manner on the outside of the second substrate, and the first active electrode and the second substrate, as well as the first loop electrode and the second substrate, are fixedly connected. The first reset element is disposed between the first substrate and the balloon, and the first reset element and the first substrate are fixedly connected. In the initial state, the first reset element is in a contracted state. After the working fluid is introduced into the balloon, the balloon drives the first reset element to synchronously change from a contracted state to an extended state.
[0013] Optionally, the first substrate and the second substrate are made of one of the following materials: PI, PET, PU, PEEK, LCP, and the first reset element is made of one of the following materials: shape memory alloy, shape memory polymer.
[0014] Optionally, the ablation electrode is a spiral ablation electrode.
[0015] Optionally, the spiral ablation electrode includes a third substrate, multiple second active electrodes, multiple second circuit electrodes, and a second reset element. One end of the third substrate is fixed to the outside of the balloon. The multiple second active electrodes and multiple second circuit electrodes correspond one-to-one. The corresponding second active electrodes and second circuit electrodes cooperate to form a spiral electrode pair. The multiple spiral electrode pairs are arranged in a ring array on the outside of the third substrate, and the spiral electrode pairs are fixedly connected to the third substrate. The second reset element is disposed between the balloon and the third substrate, and the second reset element is fixedly connected to the third substrate. In the initial state, the second reset element is in a contracted state. After the working fluid is introduced into the balloon, the balloon drives the second reset element to synchronously change from a contracted state to an extended state.
[0016] Optionally, the spiral electrode pair may be constructed in any of the following forms: logarithmic spiral, Archimedean spiral, hyperbolic spiral, or square spiral.
[0017] The embodiments of this disclosure also provide a method for determining the tissue fit of a catheter, adapted to be a radiofrequency ablation catheter as described in any of the above claims, comprising the following steps:
[0018] St1: In the initial state, a high-frequency voltage is applied to the test electrode or spiral electrode pair, and the loop current of the test electrode or spiral electrode pair is obtained.
[0019] St2: Calculate the admittance of each test electrode or spiral electrode pair based on the loop current, and then calculate the capacitance value to ground of each test electrode or the inter-electrode capacitance value of the spiral electrode pair based on the admittance, and record it as the initial capacitance value.
[0020] St3: Inject working fluid into the balloon, causing the balloon and ablation electrode to synchronously change from a contracted state to an extended state. During the extension of the ablation electrode, the capacitance to ground of each test electrode or the inter-electrode capacitance of the spiral electrode pair is recorded in real time as the real-time capacitance value. Substitute the initial capacitance value and the real-time capacitance value into the judgment formula. If the judgment formula is true, the shape of the ablation electrode has reached the expected shape; if the judgment formula is false, the shape of the ablation electrode has not reached the expected shape. The judgment formula is: Cy≥βCx, where Cx is the initial capacitance value, Cy is the real-time capacitance value, and β is the amplification coefficient.
[0021] Embodiments of this disclosure also provide an ablation system, including a radiofrequency ablation catheter and an ablation device as described in any of the preceding claims. The ablation device includes a control module, a display module, an input module, a power output module, a cooling module, a working fluid module, and a monitoring module. The control module and display module, the control module and input module, the control module and power output module, the control module and cooling module, the control module and working fluid module, the control module and monitoring module, the radiofrequency ablation catheter and power output module, the radiofrequency ablation catheter and cooling module, the radiofrequency ablation catheter and working fluid module, and the radiofrequency ablation catheter and monitoring module are all interconnected.
[0022] When a radiofrequency ablation catheter is applied, it can generate a high-frequency ablation electric field and produce heat.
[0023] The power output module can adjust the output power of the radio frequency current;
[0024] The display module can display relevant data;
[0025] The input module can input relevant parameters;
[0026] The cooling module can cool the radiofrequency ablation catheter to prevent damage to surrounding tissues due to excessive temperature.
[0027] The working medium module can input or extract the working medium into or out of the radiofrequency ablation catheter, allowing the radiofrequency ablation catheter to switch between a contracted state and an extended state.
[0028] The monitoring module can monitor the working status of the ablation catheter in real time to ensure the effectiveness of the treatment process;
[0029] The control module is configured to receive, process relevant data, and send corresponding instructions.
[0030] Compared with existing technologies, the beneficial effects of the embodiments of this disclosure include, for example:
[0031] This invention utilizes a guidewire to deliver a balloon and ablation electrode to the target location. A working fluid is introduced into the balloon through the catheter body, causing the balloon and ablation electrode to transition from a contracted to an extended state until the ablation electrode and target tissue are fully adhered. Radiofrequency current is then delivered to the ablation electrode, ablating the tissue wall. This process is repeated in multiple segments to ultimately ablate the entire duodenal cavity. This provides a viable treatment option for patients with type 2 diabetes, obesity, or other lesions of natural body cavities who do not respond well to traditional drug treatments or cannot undergo traditional surgery. Furthermore, the minimally invasive technique used in this treatment offers advantages such as minimal trauma, less patient discomfort, lower surgical risk, rapid postoperative recovery, and fewer complications.
[0032] This disclosure applies a low-amplitude high-frequency voltage to a test electrode or a spiral electrode, and then calculates the corresponding real-time capacitance and impedance values to ground by measuring the circuit current. Based on the change in the real-time capacitance value to ground, it can accurately determine whether the ablation electrode is completely attached to the target tissue, avoiding incomplete ablation caused by the misalignment of the catheter body. At the same time, based on the change in the impedance value, it can determine whether the ablation of the target tissue is complete, so as to improve the ablation efficiency and ensure the ablation effect. Attached Figure Description
[0033] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 is a schematic diagram of the overall structure in an embodiment of this disclosure;
[0035] Figure 2 is an exploded view of the overall structure in an embodiment of this disclosure;
[0036] Figure 3 is a partial structural cross-sectional view of an embodiment of this disclosure;
[0037] Figure 4 is an axial sectional view of the overall structure in an embodiment of this disclosure;
[0038] Figure 5 is an axial cross-sectional view of the ablation electrode in an embodiment of this disclosure;
[0039] Figure 6 is a schematic diagram of the structure of the ablation electrode in an embodiment of this disclosure.
[0040] Figure 7 is an axial cross-sectional view of the ablation electrode in an embodiment of this disclosure;
[0041] Figure 8 is a schematic diagram of the structure of the ablation electrode in an embodiment of this disclosure;
[0042] Figure 9 is a simulation diagram of an embodiment of this disclosure;
[0043] Figure 10 is a schematic diagram of the system framework of the ablation system in an embodiment of this disclosure;
[0044] Figure 11 is a schematic diagram of the impedance change during the ablation process in an embodiment of this disclosure.
[0045] Icons: 10. Catheter body; 11. First cavity; 12. Second cavity; 13. Balloon; 21. First substrate; 22. Second substrate; 23. Test electrode; 24. First active electrode; 25. First loop electrode; 26. First reset element; 31. Third substrate; 32. Second active electrode; 33. Second loop electrode; 34. Second reset element. Detailed Implementation
[0046] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The components of the embodiments of this disclosure described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0047] Therefore, the following detailed description of the embodiments of this disclosure provided in the accompanying drawings is not intended to limit the scope of the claimed disclosure, but merely to illustrate selected embodiments of the disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.
[0048] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0049] In the description of this disclosure, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this disclosure and simplifying the description, 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, and therefore should not be construed as a limitation of this disclosure.
[0050] Furthermore, the terms "first," "second," and "third" are configured only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.
[0051] Furthermore, the use of terms such as "horizontal," "vertical," and "suspended" does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0052] In the description of this disclosure, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.
[0053] It should be noted that, where there is no conflict, the features in the embodiments of this disclosure can be combined with each other.
[0054] Please refer to Figures 1 to 4 for an embodiment of this disclosure. This embodiment provides a radiofrequency ablation catheter, which is mainly used for reconstructing the duodenal mucosa to treat type 2 diabetes and obesity. It can also be used to treat other cavity tissue diseases, such as Barrett's esophagus and biliary stricture. The catheter includes a catheter body 10, with a first cavity 11 and a plurality of second cavities 12 inside the catheter body 10. A balloon 13 is fixed to the outside of the catheter body 10, and at least one second cavity 12 and the inside of the balloon 13 communicate with each other. An ablation electrode is assembled on the outside of the balloon 13.
[0055] In the initial state, both the balloon 13 and the ablation electrode are in a contracted state. The ablation electrode is wrapped around the outside of the balloon 13 in an involute shape, and the inner wall of the balloon 13 is in contact with the outer wall of the catheter body 10. The working fluid is introduced into the balloon 13 through the second cavity 12. The balloon 13 and the ablation electrode simultaneously change from a contracted state to an extended state. After a low-amplitude high-frequency voltage is applied to the ablation electrode simultaneously, the loop current can be obtained. The admittance and capacitance to ground of the ablation electrode can be calculated based on the loop current. Based on the capacitance to ground, it can be determined whether the ablation electrode has reached the expected shape (i.e., whether the ablation electrode is completely in contact with the target tissue).
[0056] Here, balloon 13 can be either a compliant balloon or a non-compliant balloon.
[0057] Optionally, an imaging device and a guidewire can be used in conjunction with the device. The guidewire can penetrate the inside of the first cavity 11 and plays a guiding role during the treatment process. The imaging device is configured to guide the guidewire to the target tissue. The guidewire can guide the balloon 13 and the ablation electrode to the target tissue.
[0058] It should be noted that, in order to describe the working process of this device in more detail, the following text uses the ablation of the duodenal mucosa as an example. Of course, this device can also be applied to the treatment of other cavity tissue diseases, such as Barrett's esophagus, biliary stricture, etc., which does not constitute a specific limitation.
[0059] In this embodiment, when treating patients with type 2 diabetes and obesity, a guidewire is delivered into the duodenum under the guidance of imaging equipment. Guided by the guidewire, the catheter body 10, balloon 13, and ablation electrode are delivered to the target location in the duodenum. Working fluid is introduced into the balloon 13 through the second cavity 12, causing the balloon 13 to change from a contracted state to an extended state. Simultaneously, the balloon 13 drives the ablation electrode to change from a contracted state to an extended state until the ablation electrode and the inner wall of the duodenum are completely adhered. After radiofrequency current is input into the ablation electrode, an ablation electric field is formed around the ablation electrode, thereby ablating the target tissue (i.e., the mucosa of the duodenal wall). The ablation process is repeated in multiple segments until the entire duodenal cavity is ablated. Then, the working fluid inside the balloon 13 is removed, allowing the balloon 13 and the ablation electrode to simultaneously change from an extended state to a contracted state, and the device can then be removed from the patient's body. This approach not only provides a new treatment option for diseases such as diabetes and obesity that can be treated by reconstructing the digestive tract mucosa, but also utilizes minimally invasive techniques, which have advantages such as less trauma, less patient pain, lower surgical risk, rapid postoperative recovery, and fewer complications. This provides a usable treatment option for patients with type 2 diabetes, obesity, or other cavity lesions who do not respond well to traditional drug treatment or cannot undergo traditional surgery.
[0060] It should be noted that the multiple second cavities 12 are respectively configured to store wires, introduce working fluid into the balloon 13, and transport cooling medium. The working fluid can be gas or saline. When saline is introduced into the balloon 13, the balloon 13 also has a cooling function. In this embodiment, the number of second cavities 12 is at least three. The specific number can be increased according to the usage requirements, which will not be elaborated here. The working fluid can be air.
[0061] Secondly, please refer again to Figures 4 to 6. The ablation electrode is an interdigitated ablation electrode, which includes a first substrate 21, a second substrate 22, multiple test electrodes 23, a first active electrode 24, a first circuit electrode 25, and a first reset element 26. One end of the first substrate 21 is fixed to the outside of the balloon 13 by adhesive bonding, and the length direction of the portion of the first substrate 21 and the balloon 13 that are bonded together is the same as the extension direction of the axis of the catheter body 10. The second substrate 22 is fixed to the outside of the first substrate 21. Multiple test electrodes 23 are arranged in a ring array between the first substrate 21 and the second substrate 22, and the test electrodes 23 and the first substrate 21, as well as the test electrodes 23 and the second substrate 22, are all fixedly connected. The first active electrode 24, the first circuit electrode 25, and the first circuit electrode 26 are all fixedly connected. Electrode 24 and first circuit electrode 25 are arranged in an interdigitated manner on the outside of second substrate 22, and the first active electrode 24 and second substrate 22, as well as the first circuit electrode 25 and second substrate 22, are fixedly connected. First reset element 26 is disposed between first substrate 21 and balloon 13. The surface of first reset element 26 is provided with an insulating coating, and first reset element 26 and first substrate 21 are fixedly connected. In the initial state, first reset element 26 is in a contracted state. When the working fluid input inside balloon 13 changes to an extended state, balloon 13 and first substrate 21 can drive first reset element 26 to change from a contracted state to an extended state. When first reset element 26 is in an extended state, first reset element 26 undergoes elastic deformation.
[0062] Here, a rectangular bonding area is provided at one end of the bottom of the first substrate 21. The surface of the rectangular bonding area is coated with adhesive. The first substrate 21 and the balloon 13 are bonded together by adhesive, and the length direction of the rectangular bonding area is the same as the direction of the axis of the catheter body 10.
[0063] Optionally, the first substrate 21 and the second substrate 22 are made of one of the following materials: PI, PET, PU, PEEK, LCP or other biocompatible polymer materials; the first reset element 26 is made of one of the following materials: shape memory alloy (e.g., nickel-titanium alloy, nickel-aluminum alloy, etc.), shape memory polymer (SMPs) or other materials capable of elastic deformation. In this embodiment, the first substrate 21 and the second substrate 22 are both made of PI, and the first reset element 26 can be made of nickel-titanium alloy.
[0064] It should be noted that an ablation device is also used in conjunction with this device. The test electrode 23 and the ablation device, the first active electrode 24 and the ablation device, and the first circuit electrode 25 and the ablation device are all electrically connected by wires.
[0065] In this embodiment, during ablation of the duodenal mucosa, guided by imaging equipment, a balloon 13 and ablation electrodes are delivered to the target location in the duodenum via a guidewire. Working fluid is introduced into the balloon 13 through the second cavity 12, causing the balloon 13 to change from a contracted state to an extended state. During this extension, the balloon 13 applies an outward expanding force to the first substrate 21, the second substrate 22, and the first reset element 26. The balloon 13 drives the first substrate 21, the second substrate 22, the first active electrode 24, the first circuit electrode 25, and the first reset element 26 to extend synchronously (at this time, the first reset element 26 undergoes elastic deformation and changes from a contracted state to an extended state) until the first active electrode 24 and the first circuit electrode 25 are completely adhered to the target tissue. The ablation device delivers radiofrequency current to the first active electrode 24 and the first loop electrode 25, creating an ablation electric field around them. This ablates the target tissue, and the ablation is repeated in multiple segments until the entire duodenal cavity is ablated. The working fluid inside the balloon 13 is then removed, causing the balloon 13 to change from an extended state to a contracted state. During this process, the balloon 13 gradually reduces the expansion force applied to the first substrate 21, the second substrate 22, and the first reset element 26. The first reset element 26, which undergoes elastic deformation, changes from an extended state to a contracted state. The first reset element 26 drives the first substrate 21, the second substrate 22, the first active electrode 24, and the first loop electrode 25 to simultaneously change to a contracted state, allowing the device to be removed from the patient's body.
[0066] In this embodiment, the biocompatible polymer material has good interaction with biological tissues and cells, and will not cause severe immune response, inflammatory response or toxic response, and can effectively avoid being excessively rejected by the human immune system as a foreign body; in the initial state, both the balloon 13 and the first reset element 26 are in the contracted state. The first reset element 26 in the contracted state can keep the first substrate 21, the second substrate 22, the first active electrode 24 and the first circuit electrode 25 in a similar circular shape, so as to facilitate the device to enter the target tissue. When the balloon 13 changes from the extended state to the contracted state, the elastically deformed first reset element 26 (i.e. the first reset element 26 in the extended state) can drive the first substrate 21, the second substrate 22, the first active electrode 24 and the first circuit electrode 25 to return to the contracted state.
[0067] It should be noted that in Figures 4 and 5, the extended ablation electrodes are all open-loop ring structures. In actual application, in order to ensure that the ablation electrode can completely ablate the inner wall of the target tissue, the length of the ablation electrode in the flat state is greater than the circumference of the inner wall of the target tissue. That is to say, the extended ablation electrode may not be fully extended in some areas during actual operation, and there may be local overlap, which will present a shape similar to "6". The overlapping part will not affect the formation of the ablation electric field. At the same time, since the surface of the first reset element 26 is provided with an insulating coating, there will be no sparking or electrical connection between the first reset element 26 and the first active electrode 24, or between the first reset element 26 and the first circuit electrode 25.
[0068] This embodiment is based on the previous embodiment, and the structural composition of the ablation electrode is adjusted. Specifically:
[0069] Please refer to Figures 7 and 8. The ablation electrode is a spiral ablation electrode, which includes a third substrate 31, multiple second active electrodes 32, multiple second circuit electrodes 33, and a second reset element 34. One end of the third substrate 31 is fixed to the outside of the balloon 13 by adhesive bonding. The multiple second active electrodes 32 and multiple second circuit electrodes 33 correspond one-to-one. The corresponding second active electrodes 32 and second circuit electrodes 33 cooperate with each other to form a spiral electrode pair. The multiple spiral electrode pairs are arranged in a ring array on the outside of the third substrate 31, and the spiral electrode pairs are fixedly connected to the third substrate 31. The second reset element 34 is disposed between the balloon 13 and the third substrate 31. The surface of the second reset element 34 is provided with an insulating coating, and the second reset element 34 is fixedly connected to the third substrate 31. In the initial state, the second reset element 34 is in a contracted state. After the working fluid is introduced into the balloon 13, the balloon 13 drives the second reset element 34 to change from a contracted state to an extended state synchronously. When the second reset element 34 is in an extended state, the second reset element 34 undergoes elastic deformation.
[0070] Here, the bonding method between the third substrate 31 and the balloon 13 is referred to the bonding method between the first substrate 21 and the balloon 13 in the above embodiment. The second reset element 34 and the first reset element 26 in the above embodiment are both mesh structures. Of course, the mesh structure is only one of many forms of the first reset element 26 and the second reset element 34, and can be adjusted according to actual needs. Here, it does not constitute a specific limitation.
[0071] In one embodiment, the material of the third substrate 31 is one of the following: PI, PET, PU, PEEK, LCP or other biocompatible polymer materials, and the material of the second reset element 34 is one of the following: shape memory alloy (e.g., nickel-titanium alloy, nickel-aluminum alloy, etc.), shape memory polymer (SMPs) or other materials capable of elastic deformation. In this embodiment, the material of the third substrate 31 is PI, and the material of the second reset element 34 may be nickel-titanium alloy.
[0072] Optionally, the second active electrode 32 and the ablation device, as well as the second loop electrode 33 and the ablation device, are electrically connected by wires. In this embodiment, the function, structure, and characteristics of the second reset element 34 are the same as those of the first reset element 26 in the above embodiment.
[0073] It should be noted that in Figure 7, the extended ablation electrode has an unclosed ring structure. In actual application, in order to ensure that the ablation electrode can completely ablate the inner wall of the target tissue, the length of the ablation electrode in the flat state is greater than the circumference of the inner wall of the target tissue. That is to say, the extended ablation electrode may not be fully extended in some areas during actual operation, and there may be local overlap, which will present a shape similar to "6". The overlapping part will not affect the formation of the ablation electric field. At the same time, since the surface of the second reset element 34 is provided with an insulating coating, there will be no sparking or electrical connection between the second reset element 34 and the second active electrode 32, as well as between the second reset element 34 and the second circuit electrode 33.
[0074] In this embodiment, during ablation of the duodenal mucosa, guided by imaging equipment, a balloon 13 and ablation electrodes are delivered to the target location in the duodenum via a guidewire. Working fluid is introduced into the balloon 13 through the second cavity 12, causing the balloon 13 to change from a contracted state to an extended state. During this extension, the balloon 13 applies an outward expanding force to the third substrate 31 and the second repositioning element 34. The balloon 13 drives the third substrate 31 and the second repositioning element 34 to extend synchronously (at this time, the second repositioning element 34 undergoes elastic deformation and changes from a contracted state to an extended state) until the spiral electrode pair formed by the third substrate 31 and the second active electrode 32 completely adheres to the target tissue. The device is fully adhered to the target tissue. Radiofrequency current is delivered to the spiral electrode pair via an ablation device, creating an ablation electric field around the spiral electrode pair. This ablation is then performed on the target tissue. Multiple ablation segments are repeated until the entire duodenal cavity is ablated. The working fluid inside the balloon 13 is then removed, causing the balloon 13 and the ablation electrodes to synchronously change from an extended state to a contracted state. During this process, the balloon 13 gradually reduces the expansion force applied to the third substrate 31 and the second reset element 34. The second reset element 34, which undergoes elastic deformation, changes from an extended state to a contracted state. The second reset element 34 drives the third substrate 31 and the spiral electrode pair to synchronously change to a contracted state, allowing the device to be removed from the patient's body.
[0075] In a preferred embodiment, the spiral electrode pair may be any of the following forms: logarithmic spiral, Archimedes spiral, hyperbolic spiral, square spiral, or other spiral forms. Optionally, in this embodiment, the spiral electrode pair is a square spiral.
[0076] It should be noted that Figure 8 is only a schematic diagram of the structure of a square spiral electrode pair. Other forms of spiral electrode pair structures can be adjusted according to actual usage requirements, and this does not constitute a specific limitation.
[0077] In this embodiment, the spiral electrode pair formed by the second active electrode 32 and the second circuit electrode 33 can better fit with the inner wall of the tissue. At the same time, the cooperation of multiple spiral electrode pairs can form a more continuous and uniform ablation electric field.
[0078] Optionally, as shown in Figures 6 and 8, in the above embodiments, the red electrode is the active electrode and the blue electrode is the loop electrode. Of course, this is only for distinguishing between the active electrode and the loop electrode and does not constitute a specific limitation. The active electrode and the loop electrode are both made of metals with good conductivity, such as copper or silver, and are treated with an immersion gold process. The immersion gold process can ensure that the electrode does not oxidize for a long time, thus extending the storage and use time of the electrode; on the other hand, it can prevent heavy metals such as copper and silver from directly contacting human tissue.
[0079] Optionally, in the above embodiments, the fabrication process of the ablation electrode can be a flexible printed circuit board (FPC) process.
[0080] This embodiment also provides a method for determining the tissue fit of a catheter, applicable to a radiofrequency ablation catheter in the above embodiments, including the following steps:
[0081] St1: After the balloon 13 and the ablation electrode are delivered to the target location inside the duodenum, a low-amplitude high-frequency voltage is applied to the test electrode 23 or the two arms of the spiral electrode pair (i.e., the second active electrode 32 and the second loop electrode 33) by the ablation instrument to obtain the loop current of the test electrode 23 or the spiral electrode pair.
[0082] St2: Calculate the admittance of each test electrode 23 or spiral electrode pair based on the loop current, and then calculate the capacitance value to ground of each test electrode 23 or the inter-electrode capacitance value of the spiral electrode pair based on the admittance, and record it as the initial capacitance value.
[0083] St3: Inject working fluid into balloon 13, causing balloon 13 and ablation electrode to synchronously change from a contracted state to an extended state. During the extension of the ablation electrode, the capacitance value to ground of each test electrode 23 or the inter-electrode capacitance value of the spiral electrode pair is acquired in real time and recorded as the real-time capacitance value. Substitute the initial capacitance value and the real-time capacitance value into the judgment formula. If the judgment formula is valid, the ablation electrode and the target tissue are completely adhered. If the judgment formula is invalid, the ablation electrode and the target tissue are not completely adhered. It is necessary to continue injecting working fluid into balloon 13 until the judgment formula is valid. The judgment formula is: Cy≥βCx, where Cx is the initial capacitance value, Cy is the real-time capacitance value, and β is the amplification coefficient. The value of β ranges from 1.0 to 3.0. The value of the amplification coefficient β can be determined through multiple tests and according to actual clinical needs. Here, no optional limitation is made.
[0084] Here, the inter-electrode capacitance value of the spiral electrode pair refers to the inter-electrode capacitance value between the two electrode arms in the spiral electrode pair. Specifically, it refers to the inter-electrode capacitance value between the second active electrode 32 and the second circuit electrode 33 in the same spiral electrode pair.
[0085] It should be noted that if only some test electrodes 23 have a real-time capacitance value to ground or a real-time inter-electrode capacitance value of the spiral electrode pair that is significantly greater than the real-time capacitance value to ground or a real-time inter-electrode capacitance value of other test electrodes 23 or spiral electrode pairs, it indicates that the position of the catheter body 10 has shifted. Medical staff need to make slight adjustments to the current position of the catheter body 10 to ensure that all real-time capacitance values to ground do not have significant deviations and are significantly larger than the initial capacitance values.
[0086] Optionally, calculating admittance based on loop current and calculating capacitance to ground based on admittance are both existing mature applications. The specific calculation formulas are not elaborated here. Of course, in addition to the above methods, methods such as placing a pressure sensor on the outermost side of the ablation electrode can also be used. Combining multiple methods can lead to a more accurate judgment. Among them, placing a pressure sensor on the outermost side of the ablation electrode allows the tissue wall to apply pressure to the pressure sensor after the spiral electrode pair adheres to the tissue. The pressure sensor is then used to determine whether the spiral electrode pair adheres to the tissue. Obtaining the pressure applied to the ablation electrode by the target tissue through the pressure sensor is an existing mature application. Its working principle is not elaborated here.
[0087] In a specific embodiment, please refer to Figure 9. Figure 9a is a schematic diagram when the distance between the ablation electrode and the target tissue is 0.5 mm, and Figure 9b is a schematic diagram when the distance between the ablation electrode and the target tissue is 0 mm. To illustrate the difference, only a small piece of tissue is considered to be in contact with one test electrode 23 (i.e., only one test electrode 23 can adhere to the target tissue). The multiple test electrodes 23 in the ablation electrode are numbered C1, C2...C11, C12. Among them, the test electrode 23 numbered C1 (hereinafter referred to as C1, and the others are similar) is adapted to the target tissue. When the balloon 13 drives the first substrate 21 and the second substrate 22 to extend synchronously, C1 gradually approaches the target tissue. The capacitance to ground of the test electrode 23 obtained by simulation is detailed in the table below:
[0088] As can be seen from the table, when the distance between the target tissue and C1 is 0.5 mm, the capacitance to ground of C1 is slightly greater than that of C2, C3, ..., C11, and C12. When the target tissue and C1 are in contact (distance is 0 mm), the capacitance to ground of C1 is significantly greater than that of C2 to C12 (increase by about 56%). At this time, C2 to C12 will not be in contact with the target tissue. The real-time capacitance to ground of C2 to C12 is almost equal to the initial capacitance to ground. This allows the device to accurately determine whether the ablation electrode is completely in contact with the target tissue based on the change in the real-time capacitance to ground value, thus avoiding incomplete ablation caused by the offset of the catheter body 10.
[0089] Please refer again to Figure 10. An ablation system includes an ablation device, a radiofrequency ablation catheter according to the above embodiment, and an ablation electrode according to the above embodiment. The ablation device includes a control module, a display module, an input module, a power output module, a cooling module, a working fluid module, and a monitoring module. The control module and the display module, the control module and the input module, the control module and the power output module, the control module and the cooling module, the control module and the working fluid module, the control module and the monitoring module, the radiofrequency ablation catheter and the power output module, the radiofrequency ablation catheter and the cooling module, the radiofrequency ablation catheter and the working fluid module, and the radiofrequency ablation catheter and the monitoring module are all interconnected.
[0090] When a radiofrequency ablation catheter is loaded with radiofrequency current, it can generate a high-frequency ablation electric field and produce heat through an endogenous heating effect.
[0091] The power output module can adjust the output power of the radio frequency current, thereby controlling the amount of heat generated by the ablation catheter;
[0092] The display module can display relevant data and information;
[0093] The input module can input relevant parameters;
[0094] The cooling module can cool the radiofrequency ablation catheter to prevent damage to surrounding tissues due to excessive temperature.
[0095] The working medium module can input or extract the working medium into the radiofrequency ablation catheter, allowing the radiofrequency ablation catheter to switch between a contracted and extended state, thereby conforming to treatment sites of different shapes.
[0096] The monitoring module can monitor the working status of the ablation catheter in real time to ensure the effectiveness of the treatment process;
[0097] The control module is configured to receive, process relevant data, and send corresponding instructions.
[0098] A method of using an ablation system, applicable to a radiofrequency ablation catheter, an ablation electrode, a catheter tissue fit determination method, and an ablation system as described above, includes the following steps:
[0099] Step 1: Connect the radiofrequency ablation catheter to the ablation device, and under the guidance of the imaging equipment and guidewire, deliver the balloon 13 and ablation electrode to the target location;
[0100] Step 2: Start the ablation device and input the working medium into the balloon 13 through the working medium module, so that the balloon 13 and the ablation electrode synchronously change from a contracted state to an extended state until the shape of the ablation electrode reaches the expected state (i.e., the ablation electrode and the target tissue are completely attached). During the extension process of the balloon 13 and the ablation electrode, the capacitance to ground of the test electrode 23 or the inter-electrode capacitance of the spiral electrode pair is calculated based on the circuit current, and the capacitance is used to determine whether the ablation electrode is completely attached to the target tissue.
[0101] Step 3: Radio frequency current is delivered to the ablation electrode through the power output module, so that a high-frequency ablation electric field is formed around the ablation electrode, thereby ablating the target tissue. This process is repeated in multiple segments to finally complete the ablation of the tissue to be ablated in the duodenal cavity.
[0102] Step 4: The working medium inside the balloon 13 is extracted through the working medium module, so that the balloon 13 and the ablation electrode change from the extended state to the contracted state simultaneously, and the device is removed from the patient's body.
[0103] It should be noted that in step three, determining whether the ablation electrode is completely adhered to the target tissue based on the capacitance to ground should refer to the following criteria:
[0104] Criterion 1: If all real-time capacitance values Cy are significantly increased compared to the initial capacitance value Cx (i.e., Cy≥βCx is satisfied), then everything is going smoothly and ablation can be performed successfully.
[0105] Criterion 2: If only some test electrodes 23 or spiral electrode pairs show significantly higher real-time capacitance values than others, it indicates that the position of the catheter body 10 has shifted, and the operator needs to make slight adjustments to the current position of the catheter body 10; ensure that all real-time capacitance values to ground do not deviate significantly and are significantly larger than the initial capacitance values to ground.
[0106] Criterion 3: If all real-time capacitance values Cy to ground do not change significantly relative to the initial capacitance value Cx (i.e., Cy ≥ βCx is not satisfied), then the working fluid output should be further increased to allow the ablation electrode and balloon 13 to continue to extend.
[0107] In one specific embodiment, due to the long length of the entire duodenal cavity, ablation is often not possible in a single operation. The length of a single ablation area can be set from 1cm to 10cm depending on the different cavity tissues and ablation requirements. After multiple segmental ablations, the ablation of the entire cavity tissue to be ablated is finally completed. To determine whether the ablation is complete, during the delivery of radiofrequency current to the ablation electrodes, the impedance values of each test electrode 23 or each spiral electrode pair are obtained through the loop current, and the following criteria are referenced:
[0108] Rule 1: If there is a period of decreasing impedance value at the beginning of ablation, then the ablation process is normal and ablation can continue.
[0109] Criterion 2: If there are no problems during the ablation process, the real-time capacitance to ground value shows a monotonically decreasing trend with the ablation time.
[0110] Criterion 3: If the impedance value increases significantly after ablation for a period of time and does not change significantly for a certain period of time (e.g., 10s or 20s), then the ablation at the current location is considered complete.
[0111] Please refer to Figure 11. At the beginning of ablation, there is a period of decreasing impedance value, which can be used to determine whether normal ablation has been performed. During the ablation process, the impedance value first decreases and then increases, eventually stabilizing. Based on the change in impedance value, it is possible to determine whether the ablation of the target tissue has been completed, so as to improve ablation efficiency and ensure ablation effect.
[0112] The working principle of this disclosure is as follows:
[0113] When treating patients with type 2 diabetes and obesity, a guidewire is delivered into the duodenum under the guidance of imaging equipment. Guided by the guidewire, the catheter body 10 is delivered to the target location in the duodenum, so that the ablation electrode and the target location are matched. Working fluid is introduced into the balloon 13, so that the balloon 13 and the ablation electrode synchronously change from a contracted state to an extended state until the ablation electrode and the inner wall of the duodenum are completely adhered. After the radiofrequency current is introduced into the ablation electrode, an ablation electric field is formed around the ablation electrode, thereby ablating the target tissue. Multiple segments of ablation are repeated until the tissue in the entire duodenum is ablated. Then the working fluid inside the balloon 13 is removed, so that the balloon 13 and the ablation electrode synchronously change from an extended state to a contracted state, and the device can be removed from the patient's body.
[0114] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims. Industrial applicability
[0115] In summary, this disclosure provides a radiofrequency ablation catheter, a method for determining catheter tissue fit, and an ablation system. Guided by a guidewire, a balloon and ablation electrode are delivered to the target location. Working fluid is introduced into the balloon through the catheter body, causing the balloon and ablation electrode to change from a contracted state to an extended state until the ablation electrode and target tissue are completely fitted. Radiofrequency current is then delivered to the ablation electrode, ablating the tissue wall. This process is repeated in multiple segments to ultimately ablate the entire duodenal cavity. This method is suitable for patients with type 2 diabetes, obesity, or other lesions of natural body cavities who do not respond well to traditional drug treatment or cannot undergo traditional surgery. This invention provides a usable treatment option that utilizes minimally invasive techniques, offering advantages such as minimal trauma, less patient discomfort, lower surgical risk, rapid postoperative recovery, and fewer complications. By applying a low-amplitude high-frequency voltage to the test electrode or spiral electrode, and then calculating the corresponding real-time capacitance and impedance values to ground by measuring the circuit current, the change in real-time capacitance to ground can accurately determine whether the ablation electrode is fully aligned with the target tissue, avoiding incomplete ablation caused by catheter misalignment. Simultaneously, the change in impedance value can determine whether the target tissue ablation is complete, thereby improving ablation efficiency and ensuring ablation effect.
Claims
1. A radiofrequency ablation catheter, characterized in that: The catheter body (10) includes a first cavity (11) and a plurality of second cavities (12) inside the catheter body (10). A balloon (13) is fixed on the outside of the catheter body (10), and at least one second cavity (12) and the interior of the balloon (13) are interconnected. An ablation electrode is mounted on the outside of the balloon (13). In the initial state, both the balloon (13) and the ablation electrode are in a contracted state. The ablation electrode is wrapped around the outside of the balloon (13) in an involute shape, and the inner wall of the balloon (13) is in contact with the outer wall of the catheter body (10). The working fluid is introduced into the balloon (13) through the second cavity (12). The balloon (13) and the ablation electrode simultaneously change from a contracted state to an extended state. After a high-frequency voltage is applied to the ablation electrode simultaneously, the capacitance value to ground of the ablation electrode is calculated and the shape of the ablation electrode is determined.
2. The radiofrequency ablation catheter according to claim 1, characterized in that: The ablation electrode is an interdigitated ablation electrode.
3. The radiofrequency ablation catheter according to claim 2, characterized in that: The interdigitated ablation electrode includes a first substrate (21), a second substrate (22), multiple test electrodes (23), a first active electrode (24), a first loop electrode (25), and a first reset element (26). One end of the first substrate (21) is fixed to the outside of the balloon (13) by adhesive bonding. The second substrate (22) is fixed to the outside of the first substrate (21). Multiple test electrodes (23) are arranged in a ring array between the first substrate (21) and the second substrate (22). The test electrodes (23) and the first substrate (21) and the test electrodes (23) and the second substrate (22) are all fixedly connected. The first active electrode... The first active electrode (24) and the first circuit electrode (25) are arranged in an interdigitated manner on the outside of the second substrate (22), and the first active electrode (24) and the second substrate (22) and the first circuit electrode (25) and the second substrate (22) are fixedly connected. The first reset element (26) is disposed between the first substrate (21) and the balloon (13), and the first reset element (26) and the first substrate (21) are fixedly connected. In the initial state, the first reset element (26) is in a contracted state. After the working medium is introduced into the balloon (13), the balloon (13) drives the first reset element (26) to change from a contracted state to an extended state synchronously.
4. The radiofrequency ablation catheter according to claim 3, characterized in that: The first substrate (21) and the second substrate (22) are made of one of the following materials: PI, PET, PU, PEEK, LCP.
5. The radiofrequency ablation catheter according to claim 3 or 4, characterized in that, The first reset element (26) is made of one of the following materials: memory alloy or shape memory polymer.
6. The radiofrequency ablation catheter according to claim 1, characterized in that: The ablation electrode is a spiral-shaped ablation electrode.
7. The radiofrequency ablation catheter according to claim 6, characterized in that: The spiral ablation electrode includes a third substrate (31), multiple second active electrodes (32), multiple second circuit electrodes (33), and a second reset element (34). One end of the third substrate (31) is fixed to the outside of the balloon (13) by adhesive bonding. The multiple second active electrodes (32) and multiple second circuit electrodes (33) correspond one-to-one. The corresponding second active electrodes (32) and second circuit electrodes (33) cooperate with each other to form a spiral electrode pair. The multiple spiral electrode pairs are arranged in a ring array on the outside of the third substrate (31), and the spiral electrode pairs are fixedly connected to the third substrate (31). The second reset element (34) is disposed between the balloon (13) and the third substrate (31), and the second reset element (34) is fixedly connected to the third substrate (31). In the initial state, the second reset element (34) is in a contracted state. After the working fluid is introduced into the balloon (13), the balloon (13) drives the second reset element (34) to change from a contracted state to an extended state synchronously.
8. The radiofrequency ablation catheter according to claim 7, characterized in that: The structure of the spiral electrode pair can be any of the following: logarithmic spiral, Archimedean spiral, hyperbolic spiral, or square spiral.
9. The radiofrequency ablation catheter according to claim 7 or 8, characterized in that, The material of the third substrate is one of the following: PI, PET, PU, PEEK, LCP.
10. The radiofrequency ablation catheter according to any one of claims 7 to 9, characterized in that, The material of the second reset element is one of the following: shape memory alloy or shape memory polymer.
11. The radiofrequency ablation catheter according to any one of claims 1 to 10, characterized in that, The ablation electrode is manufactured using flexible circuit board technology.
12. The radiofrequency ablation catheter according to any one of claims 1 to 11, characterized in that, The surface of the ablation electrode is treated with an immersion gold process.
13. A method for determining the tissue fit of a catheter, applicable to a radiofrequency ablation catheter according to any one of claims 1 to 12, characterized in that: Includes the following steps: St1: In the initial state, a high-frequency voltage is applied to the test electrode (23) or the spiral electrode pair, and the loop current of the test electrode (23) or the spiral electrode pair is obtained. St2: Calculate the admittance of each test electrode (23) or spiral electrode pair based on the loop current, and then calculate the capacitance value to ground of each test electrode (23) or the inter-electrode capacitance value of the spiral electrode pair based on the admittance, and record it as the initial capacitance value. St3: Introduce working fluid into the balloon (13) so that the balloon (13) and the ablation electrode can be synchronously changed from a contracted state to an extended state. During the extension of the ablation electrode, the capacitance value to ground of each test electrode (23) or the inter-electrode capacitance value of the spiral electrode pair is obtained in real time and recorded as the real-time capacitance value. Substitute the initial capacitance value and the real-time capacitance value into the judgment formula. If the judgment formula is valid, the shape of the ablation electrode reaches the expected shape. If the determination formula is not valid, the shape of the ablation electrode has not reached the expected shape. The determination formula is: Cy≥βCx, where Cx is the initial capacitance value, Cy is the real-time capacitance value, and β is the amplification coefficient.
14. An ablation system, characterized in that: The invention includes a radiofrequency ablation catheter and ablation device according to any one of claims 1 to 7, wherein the ablation device comprises a control module, a display module, an input module, a power output module, a cooling module, a working fluid module, and a monitoring module, wherein the control module and display module, the control module and input module, the control module and power output module, the control module and cooling module, the control module and working fluid module, the control module and monitoring module, the radiofrequency ablation catheter and power output module, the radiofrequency ablation catheter and cooling module, the radiofrequency ablation catheter and working fluid module, and the radiofrequency ablation catheter and monitoring module are all interconnected; When a radiofrequency ablation catheter is applied, it can generate a high-frequency ablation electric field and produce heat. The power output module can adjust the output power of the radio frequency current; The display module can display relevant data; The input module can input relevant parameters; The cooling module can cool the radiofrequency ablation catheter to prevent damage to surrounding tissues due to excessive temperature. The working medium module can input or extract the working medium into or out of the radiofrequency ablation catheter, allowing the radiofrequency ablation catheter to switch between a contracted state and an extended state. The monitoring module can monitor the working status of the ablation catheter in real time to ensure the effectiveness of the treatment process; The control module is configured to receive, process relevant data, and send corresponding instructions.
15. A method of using an ablation system, applicable to the ablation system as described in claim 14, comprising the following steps: The radiofrequency ablation catheter is connected to the ablation device, and under the guidance of imaging equipment and guidewire, the balloon and ablation electrode are delivered to the target location; The ablation device is activated, and working fluid is introduced into the balloon through the working fluid module, so that the balloon and the ablation electrode synchronously change from a contracted state to an extended state until the shape of the ablation electrode reaches the expected state. During the extension process of the balloon and the ablation electrode, the capacitance to ground of the test electrode or the inter-electrode capacitance of the spiral electrode pair is calculated based on the circuit current, and the capacitance is used to determine whether the ablation electrode is completely attached to the target tissue. Radio frequency current is delivered to the ablation electrode through the power output module, so that a high-frequency ablation electric field is formed around the ablation electrode, thereby ablating the target tissue. Multiple ablations are repeated to finally complete the ablation of the tissue to be ablated in the duodenal cavity. The working medium inside the balloon is extracted by the working medium module, so that the balloon and the ablation electrode simultaneously change from an extended state to a contracted state, and the device is removed from the patient's body.