Lung ablation catheter, detection method and ablation system

Abstract

The invention belongs to the field of medical instruments, and discloses a lung ablation catheter, a detection method and an ablation system.The lung ablation catheter comprises a mesh basket support, a catheter assembly and a plurality of electrodes, the mesh basket support comprises a plurality of branch supports, the far ends of the branch supports converge together, and the near ends of the branch supports converge together; the branch stent comprises a branch far-end section, a branch middle section and a branch near-end section; the catheter assembly is connected with the near end of the net basket support, and more than two electrodes are arranged on each branch middle section at intervals; the mesh basket support is controlled by the catheter assembly to have a contraction state and an unfolding state, in the unfolding state, the deformation amount of the branch middle section is smaller than the deformation amount of the branch far-end section and the branch near-end section, the branch middle section is parallel to the central axis of the mesh basket support, and the electrode is made to be attached to the airway wall of the lung. When the mesh basket stent is unfolded under stress, the deformation of the branch middle section is smaller than that of the branch far-end section and the branch near-end section, so that the electrode is attached to the airway wall of the bronchus in parallel as far as possible, and the ablation effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a pulmonary ablation catheter, a detection method and an ablation system. Background Art

[0002] Lung ablation catheters are usually used in conjunction with bronchoscopes to perform ablation after reaching the target location through the bronchus. Compared with surgical operations, they are less invasive and safer. Currently, conventional lung ablation catheters generally include an electrode assembly at the distal end, which releases energy (such as electric pulses and radio frequency) by contacting the electrodes with the lung tissue to achieve the purpose of ablation.

[0003] Conventional electrode catheters have head shapes such as monopolar, annular, balloon, and basket. The electrode assembly is located at the distal end of the catheter. Several types of catheters have certain limitations during ablation. For example, a single-electrode catheter can only be used for point-shaped ablation, and the efficiency of ablation of the inner wall of annular bronchus is low. Annular catheters can achieve full-circle ablation, but the process of adjustable annular rings is complex and can only meet airway sizes within a certain range. Basket catheters can achieve full-circle ablation, but the basket catheter structure in the prior art is unstable when placed against a straight channel.

[0004] Existing basket catheter structure such as Figure 1 As shown in the figure, the basket is composed of multiple branches, and multiple electrodes are arranged on the branches. When the basket is expanded, it is generally spherical or fusiform, and the equator is the part with the largest diameter after the basket is expanded. When used for bronchial ablation in the lungs, the bronchus is a straight channel. When the electrode contacts the airway wall, only the equatorial part is well attached, while the non-equatorial part is not stable, which can easily cause uneven energy distribution and low conduction efficiency. In addition, the airway is an air environment, and the impedance is much greater than the impedance of the tissue itself. When the electrode is not attached well, it is easy to cause the current circuit to be broken, affecting the treatment effect. Summary of the invention

[0005] The purpose of the present invention is to provide a lung ablation catheter, a detection method and an ablation system, which can make the electrode fit well with the airway wall and improve the ablation effect.

[0006] The technical solution provided by the present invention is as follows:

[0007] In one aspect, a pulmonary ablation catheter is provided, comprising:

[0008] The basket support comprises a plurality of branch supports arranged at intervals along the circumferential direction, the distal ends of the plurality of branch supports are respectively gathered together, the proximal ends of the plurality of branch supports are respectively gathered together, and the branch supports are sequentially divided into a branch distal end section, a branch middle section and a branch proximal end section along the distal to proximal direction;

[0009] a catheter assembly, the main body section of which is connected to the proximal end of the basket stent;

[0010] A plurality of electrodes, wherein two or more electrodes are arranged at intervals on the middle section of each branch;

[0011] The basket support is controlled by the catheter assembly to have a contracted state and an expanded state. In the expanded state, the deformation of the middle section of the branch is smaller than the deformation of the distal section of the branch and the proximal section of the branch. The middle section of the branch is parallel to the central axis of the basket support so that the electrode fits against the airway wall of the lungs.

[0012] In the present technical solution, the deformation of different parts of the branch stent is controlled by controlling the stiffness or thickness of the distal, middle and proximal sections of the branch stent, thereby controlling the shape of the catheter after deployment, so as to achieve good contact with the airway tissue.

[0013] In some embodiments, the basket stent further includes a distal fixing portion and a proximal fixing portion, the distal ends of a plurality of the branch stents converge and are connected to the distal fixing portion, the proximal ends of a plurality of the branch stents converge and are connected to the proximal fixing portion, and the catheter assembly is connected to the proximal fixing portion.

[0014] In some embodiments, the branch stent is made of a shape-shaped memory alloy so that the stiffness of the middle section of the branch is greater than the stiffness of the distal section of the branch and the proximal section of the branch.

[0015] In some embodiments, the cross-sectional area of ​​the middle segment of the branch is greater than the cross-sectional area of ​​the distal segment of the branch and the proximal segment of the branch; or the thickness of the middle segment of the branch along the expansion-contraction direction is greater than the thickness of the distal segment of the branch and the proximal segment of the branch along the expansion-contraction direction.

[0016] In some embodiments, the minimum radial thickness of the basket support in the middle section of the branch is greater than the maximum radial thickness of the basket support in the distal section of the branch and the proximal section of the branch, wherein the radial thickness of the basket support is the thickness of the basket support along the expansion-contraction direction.

[0017] In some embodiments, the stiffness of the branch distal segment is less than or equal to the stiffness of the branch proximal segment, so that when the basket support is unfolded, the deformation of the branch distal segment is greater than or equal to the deformation of the branch proximal segment.

[0018] In some embodiments, when the basket stent is expanded, the angle between the distal end segment of the branch and the extension line of the line connecting the proximal and distal centers of the basket stent is less than 90 degrees.

[0019] In the present technical solution, a catheter structure with an inwardly retracted catheter tip is designed to eliminate the blind spot under the microscope, so that there is no uncontrollable catheter part outside the scope of observation under the microscope to avoid accidental injury; in addition, the basket stent in the present technical solution has a self-expanding effect, which can not only achieve good adhesion of the electrode, but also adapt to different airway sizes.

[0020] In some embodiments, the branch distal segment includes more than two arms, one end of the two or more arms are respectively connected to the distal fixing portion and are arranged at intervals, and the other ends are connected to the corresponding branch middle segment.

[0021] In the present technical solution, a multi-arm branch stent structure is designed at the distal end of the branch to increase the stability of each branch stent of the catheter.

[0022] In some embodiments, the plurality of branch supports include a first branch support and a second branch support that are spaced apart, a first electrode and a second electrode are distributed on the first branch support, and the first electrode and the second electrode form a first electrode group;

[0023] A third electrode is distributed on the second branch support. The third electrode and the first electrode are located at the same radial cross section of the basket support. The first electrode and the third electrode form a second electrode group.

[0024] In some embodiments, the basket support further includes a plurality of connecting segments, and the proximal end of each branch support is respectively connected to a connecting segment, and the width of the branch support is smaller than the width of the connecting segment, so that the spacing between two adjacent branch supports is smaller than the spacing between two adjacent connecting segments, and the plurality of connecting segments are fixed to the proximal fixing portion.

[0025] In some embodiments, a central rod is further included, the central rod passing through the center of the basket support, the distal fixing portion is fixed to one end of the central rod, and the proximal fixing portion is movably connected to the other end of the central rod.

[0026] In some embodiments, the branch distal segment, the branch middle segment, and the branch proximal segment are split structures.

[0027] On the other hand, a detection method using a lung ablation catheter is also provided, which determines whether the shape of the basket stent after expansion is normal and whether the state of the electrode is normal based on the impedance measured by the first electrode group and the impedance measured by the second electrode group.

[0028] In this technical solution, the impedances measured in different modes and their relationships can be used to determine whether the basket support has a normal unfolding shape, whether the electrode state is normal, and whether the current loop is normal.

[0029] In some embodiments, the method further includes calculating the distance between the first branch support and the second branch support based on the impedance measured by the first electrode group, the distance between the first electrode and the second electrode, and the impedance measured by the second electrode group.

[0030] In some embodiments, it also includes: calculating the size of the airway in contact with the middle section of the branch according to the distance between each branch stent in the contact state between the basket stent and the airway wall, the number of the branch stents and the width of the middle section of the branch.

[0031] In this technical solution, the catheter has the function of impedance detection, which can determine the adhesion situation; it can also calculate information such as the distance between branches and airway size through impedance detection in different modes.

[0032] In some embodiments, it also includes: determining ablation focus shape information based on the impedance measured by the first electrode group and the impedance measured by the second electrode group, and judging whether supplementary ablation is needed based on the ablation focus shape information and the distance between the branch stents, and when supplementary ablation is needed, obtaining the supplementary ablation position and the catheter rotation angle.

[0033] In this technical solution, different modes of discharge can achieve both mapping and ablation functions. Changing the energy parameters can also adapt the ablation catheter to different indications, and can also provide certain suggestions and guidance for ablation treatment based on simulation calculations.

[0034] On the other hand, an ablation system is provided, comprising a bronchoscope, a camera and the lung ablation catheter described in any one of the above embodiments, wherein a working channel is provided in the bronchoscope, the camera is arranged at the distal end of the bronchoscope, and the lung ablation catheter is arranged in the working channel.

[0035] The technical effects of the present invention are:

[0036] (1) The stiffness of the middle section of the branch is greater than that of the distal section and the proximal section of the branch. When the basket stent is deployed under force, the deformation of the middle section of the branch is smaller than that of the distal section and the proximal section of the branch, so that the middle section of the branch is as parallel to the bronchial airway wall as possible, so that the energy distribution is uniform, and the conduction efficiency and ablation effect are improved.

[0037] (2) A multi-arm stent structure is designed at the distal end of the branch stent to increase the stability of each branch stent and solve the problem of catheter branch displacement.

[0038] (3) The head end of the basket bracket is designed to be retracted, which can eliminate the blind spot under the microscope, so that there is no uncontrollable part of the catheter outside the scope of observation under the microscope, avoiding accidental injuries.

[0039] (4) The basket stent has a self-expanding effect, which not only enables good adhesion of the electrode but also can adapt to different airway sizes.

[0040] (5) The catheter has an impedance detection function, which can determine the adhesion status. It can also calculate information such as the distance between branches and airway size through impedance detection in different modes.

[0041] (6) Using the impedances measured in different modes and their relationships, it is possible to determine whether the basket shape is normal, whether the electrode state is normal, and whether the current loop is normal.

[0042] (7) Different modes of discharge can achieve both mapping and ablation functions. Changing the energy parameters can also adapt the catheter to different indications. It can also provide certain suggestions and guidance for ablation treatment based on simulation calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0044] Figure 1 It is a schematic diagram of the structure of the basket catheter after being unfolded in the prior art;

[0045] Figure 2 is a schematic structural diagram of an initial state of a pulmonary ablation catheter according to Embodiment 1 of the present application;

[0046] Figure 3 This is a schematic structural diagram of a pulmonary ablation catheter in the first embodiment of the present application when it is deployed;

[0047] Figure 4 Schematic diagram of the thickness structure of different sections of the branch stent in Example 1 of the present application;

[0048] Figure 5 It is a schematic diagram of the width structure of different areas of the basket support of Example 1 of the present application;

[0049] Figure 6 is a schematic diagram of electrode distribution of a lung ablation catheter according to Embodiment 1 of the present application;

[0050] Figure 7 is a schematic diagram of electrode ablation of a lung ablation catheter according to the first embodiment of the present application;

[0051] Figure 8 is a schematic structural diagram of the branch bracket of the first embodiment of the present application when it does not slide sideways;

[0052] Fig. 9 It is a schematic diagram of the structure of the branch bracket when sliding sideways in the first embodiment of the present application;

[0053] Fig.10is a schematic structural diagram of a branch distal end section of a pulmonary ablation catheter according to Embodiment 2 of the present application;

[0054] Fig.11 yes Fig.10 Enlarged view of point A in the middle;

[0055] Fig.12 This is a schematic diagram of a blind area of ​​vision when the lung ablation catheter of Example 1 of the present application is used;

[0056] Fig.13 is a schematic structural diagram of the lung ablation catheter of Example 3 of the present application when deployed;

[0057] Fig.14 is a schematic diagram of the morphology of a single branch stent when the pulmonary ablation catheter of Example 1 of the present application is deployed;

[0058] Fig.15 is a schematic diagram of the morphology of a single branch stent when the pulmonary ablation catheter of Example 3 of the present application is deployed;

[0059] Fig.16 It is a schematic structural diagram of the basket stent of the lung ablation catheter in the fourth embodiment of the present application in the initial state.

[0060] Description of Figure Numbers:

[0061] 10. Basket support; 11. Distal fixing part; 12. Branch support; 1201. First branch support; 1202. Second branch support; 121. Distal branch segment; 1211. Support arm; 122. Middle branch segment; 123. Proximal branch segment; 124. Metal sheet; 13. Proximal fixing part; 14. Connecting segment; 15. Center rod; 20. Electrode; 21. First electrode; 22. Second electrode; 23. Third electrode; 30. Airway wall; 40. Bronchoscope; 41. Working channel; 50. Camera; 60. Ablation focus. DETAILED DESCRIPTION

[0062] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0063] In order to simplify the drawings, only the parts related to the present invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0064] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0065] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0067] In the present application, the terms "proximal" and "distal" refer to the relative orientation, relative position, and direction of components or actions relative to each other from the perspective of a doctor using the medical device. Although "proximal" and "distal" are not restrictive, "proximal" usually refers to the end of the medical device that is close to the doctor during normal operation, and "distal" usually refers to the end that first enters the patient's body.

[0068] Embodiment 1

[0069] like Figure 2 and Figure 3As shown, a pulmonary ablation catheter comprises a basket support 10, a plurality of electrodes 20 and a catheter assembly, wherein the basket support 10 comprises a plurality of branch supports 12 arranged at intervals along the circumferential direction, wherein the distal ends of the plurality of branch supports 12 are respectively gathered together, and the proximal ends of the plurality of branch supports 12 are respectively gathered together, and the branch supports 12 are divided into a branch distal end segment 121, a branch middle segment 122 and a branch proximal end segment 123 in the direction from the distal end to the proximal end, and the branch distal segment 121, the branch middle segment 122 and the branch proximal end segment 123 are respectively .... 3 can be an integrated structure or a split structure; the main section of the catheter assembly is connected to the proximal end of the basket support 10; each branch middle section 122 is provided with two or more electrodes 20 at intervals; the basket support 10 is controlled by the catheter assembly to have a contracted state and an expanded state, in which the deformation of the branch middle section 122 is smaller than that of the branch distal section 121 and the branch proximal section 123, and the branch middle section 122 is parallel to the central axis of the basket support 10, so that the electrode 20 fits the airway wall 30 of the lung.

[0070] Specifically, Figure 2 It is a schematic diagram of the structure of the basket support 10 when it is not deployed. When the basket support 10 is not deployed, the multiple branch supports 12 are not deformed, and the multiple branch supports 12 are parallel to the central axis of the basket support 10. The shape of the entire basket support 10 is approximately cylindrical. When the basket support 10 needs to be deployed, the proximal end of the basket support 10 is pushed toward the distal end by operating the catheter assembly, so that the multiple branch supports 12 are deformed. Since the deformation of the branch middle section 122 is less than the deformation of the branch distal section 121 and the deformation of the branch proximal section 123, the basket support 10 presents a special shape after deployment. For example, each branch support 12 and the central axis of the basket support 10 can form a parallelogram, a trapezoid, an irregular quadrilateral and other shapes. The shape of the basket support 10 after deployment is as follows: Figure 3 As shown, at this time, the branch middle section 122 is approximately parallel to the central axis of the basket support 10, and the airway is a straight channel, and the airway wall 30 is also approximately parallel to the central axis of the basket support 10, so that the branch middle section 122 can better fit the airway wall 30, and then the electrode 20 on the branch middle section 122 can be well attached to the airway wall 30. During ablation, good attachment can make the energy evenly transmitted. In this embodiment, the electrodes 20 are mainly distributed on the branch middle section 122. Of course, if in some special application scenarios, it is necessary to arrange the electrodes 20 on the branch proximal section 123 or the branch distal section 121, the electrodes 20 can also be arranged on the branch proximal section 123 and / or the branch distal section 121, and this embodiment does not limit it.

[0071] In this embodiment, the deformation of the branch middle section 122 is set to be smaller than the deformation of the branch distal section 121 and the branch proximal section 123. When a certain stress is applied to the branch stent 12, different sections on the branch stent 12 produce different degrees of deformation, so that the branch middle section 122 is as parallel to the bronchial airway wall 30 as possible, so that the energy distribution is uniform, thereby improving the conduction efficiency and ablation effect.

[0072] Furthermore, the basket support 10 further includes a distal fixing portion 11 and a proximal fixing portion 13, the distal ends of the plurality of branch supports 12 converge and are respectively connected to the distal fixing portion 11, and the plurality of branch supports 12 are evenly spaced along the circumference of the distal fixing portion 11, and the proximal ends of the plurality of branch supports 12 converge and are connected to the proximal fixing portion 13, for example, by a hinge or other movable connection; in this embodiment, the distal ends of the plurality of branch supports 12 can be fixed together by the distal fixing portion 11, and the proximal ends of the plurality of branch supports 12 can be fixed together by the proximal fixing portion 13. Of course, other embodiments can also be used to converge the distal ends and proximal ends of the branch supports 12 respectively and make the branch distal segment 121 and the branch proximal segment 123 movable.

[0073] In this embodiment, there are multiple implementation methods for achieving different deformation amounts of different segments of the branch stent 12. Implementation method 1 is to use memory alloy to shape the branch middle segment 122 so that the stiffness is greater than the stiffness of the branch distal segment 121 and the branch proximal segment 123. The branch stent 12 is shaped after heat treatment. Figure 3 In this embodiment, the cross-sectional areas of the branch distal segment 121, the branch middle segment 122 and the branch proximal segment 123 are substantially the same, and the cross-sectional shapes of the branch distal segment 121, the branch middle segment 122 and the branch proximal segment 123 can be rectangular cross-sections, I-shaped cross-sections, etc.

[0074] The second embodiment is to control the shape of the basket support 10 after expansion by changing the cross-sectional area or thickness, that is, the cross-sectional area of ​​the branch middle section 122 is greater than the cross-sectional area of ​​the branch distal section 121 and the branch proximal section 123, or the thickness of the branch middle section 122 along the expansion-contraction direction is greater than the thickness of the branch distal section 121 and the branch proximal section 123 along the expansion-contraction direction, such as Figure 4 As shown. When the cross-sectional shapes are basically the same everywhere, the larger the cross-sectional area or thickness of the middle section 122 of the branch, the smaller the deformation. Exemplarily, the branch stent 12 uses a tube that has a gradual / mutated wall thickness structure. The thickness of the middle section 122 of the branch along the expansion-contraction direction is h1, the thickness of the distal section 121 of the branch along the expansion-contraction direction is h2, and the thickness of the proximal section 123 of the branch along the expansion-contraction direction is h3, h1>h2, and h1>h3; the tube can be integrally formed or post-processed, and this method is more difficult to process, such as Figure 4As shown, a pipe with uniform thickness can be used, and a metal sheet 124 can be attached to the branch middle section 122 by welding or gluing to increase the thickness so as to achieve a thickness difference. Of course, the above effect can also be achieved with the same cross-sectional area and different cross-sectional shapes, such as the cross-sections of the branch distal section 121 and the branch proximal section 123 are regular polygons, which gradually or suddenly change to an "I" shape along the expansion-contraction direction of the basket support 10, so that the material acquires anisotropy and is more difficult to deform in the expansion-contraction direction, thereby achieving an equivalent effect with different stiffness in different regions of the basket support 10.

[0075] The third embodiment is to control the stiffness by changing the radial thickness of the basket support 10, such as Figure 5 As shown, the minimum radial thickness of the basket support 10 in the branch middle section 122 is greater than the maximum radial thickness of the basket support 10 in the branch distal section 121 and the branch proximal section 123, wherein the radial thickness of the basket support 10 is the thickness of the basket support 10 along the expansion-contraction direction.

[0076] like Figure 5 As shown, the radial thickness of the basket support 10 in the branch distal section 121 and the branch proximal section 123 is a1, and the radial thickness of the basket support 10 in the branch middle section 122 is a2, a1<a2. It should be noted that the radial thickness of the basket support 10 in the branch distal section 121, the branch middle section 122 and the branch proximal section 123 is not necessarily uniform, and a radial thickness gradient structure can also be adopted.

[0077] In this embodiment, when the stiffness of the branch distal segment 121 is equal to the stiffness of the branch proximal segment 123, when the basket support 10 is unfolded, the deformation of the branch distal segment 121 is the same as the deformation of the branch proximal segment 123. After the basket support 10 is unfolded, the angle between the branch distal segment 121 and the extension line of the proximal-distal center line of the basket support 10 is greater than 90 degrees. The branch support 12 and the proximal-distal center line (central axis) of the basket support 10 can form a trapezoidal structure. The branch distal segment 121 and the branch proximal segment 123 together form a bridge-like structure to provide stable support for the branch middle segment 122.

[0078] Furthermore, the pulmonary ablation catheter of this embodiment can also realize the detection function that is difficult to realize with conventional ablation catheters through the electrodes provided. Figure 6 As shown, the plurality of branch brackets 12 include a first branch bracket 1201 and a second branch bracket 1202 arranged at intervals, the first branch bracket 1201 is provided with a first electrode 21 and a second electrode 22, the first electrode 21 and the second electrode 22 form a first electrode group; the second branch bracket 1202 is provided with a third electrode 23, the third electrode 23 and the first electrode 21 are located at the same radial cross section of the basket bracket 10, the first electrode 21 and the third electrode 23 form a second electrode group。

[0079] The detection method of the lung ablation catheter using the above electrode structure includes:

[0080] According to the impedance measured by the first electrode group and the impedance measured by the second electrode group, it can also be determined whether the shape of the basket support 10 after unfolding is normal and whether the state of the electrode 20 is normal.

[0081] Under normal use, the impedance measured by the first electrode group and the impedance measured by the second electrode group should be within their respective preset ranges. If the impedance measured by the first electrode group and / or the impedance measured by the second electrode group are not within their respective preset ranges, it means that the expanded form of the basket support 10 is abnormal, or the state of the electrode 20 is abnormal. If the impedance measured by the first electrode group and the impedance measured by the second electrode group are within their respective preset ranges, it means that the expanded form of the basket support 10 is normal, and the state of the electrode 20 is normal. At the same time, the current generally flows in the direction of lower impedance, and the impedance measured by the first electrode group and the second electrode group can also be used to confirm whether the applied energy will form the expected current loop. If a change occurs, the energy release can be stopped at any time.

[0082] Furthermore, it also includes: calculating the distance between the first branch bracket 1201 and the second branch bracket 1202 according to the impedance measured by the first electrode group, the distance between the first electrode 21 and the second electrode 22, and the impedance measured by the second electrode group.

[0083] Because on the same branch stent 12, no matter how the spacing between the branch stents 12 changes, the spacing between the two electrodes 20 on the same branch stent 12 will not change. That is to say, no matter what the shape of the ablation catheter is, as long as effective contact is formed, the tissue impedance measured by the first electrode group will not change. Assuming that the impedance measured by the first electrode group is x at this time, when the ablation catheter matches airways of different sizes, when the basket stent 10 is expanded to form effective contact, the equatorial size of the basket stent 10 is different, resulting in different spacing between the branch stents 12. At this time, one electrode 20 (i.e., the first electrode 21 and the third electrode 23) located at the same airway cross section is selected between the two branch stents 12 to form a second electrode group. The spacing between the first electrode 21 and the third electrode 23 in the second electrode group is b. The spacing between the first electrode 21 and the third electrode 23 can be approximately considered as the spacing between the first branch stent 1201 and the second branch stent 1202. The impedance measured by the second electrode group will also change with the spacing between the branch stents 12. Assuming that the impedance measured by the second electrode group is y, at this time, the ratio between the impedance x measured by the first electrode group and the impedance y measured by the second electrode group is the ratio between the spacing b of the branch stent 12 and the spacing a of the electrodes 20 in the first electrode group, i.e., the spacing b of the branch stent 12 = a*y / x. This method can be used to calculate the spacing between each branch stent 12 in the attached state, for example, the spacing between two adjacent branch stents 12 or the spacing between two spaced branch stents 12 can be calculated.

[0084] After calculating the spacing between each branch stent 12 in the abutting state, the size of the airway abutting against the branch middle section 122 can also be calculated based on the spacing between each branch stent 12 in the abutting state between the basket stent 10 and the airway wall 30, the number of branch stents 12 and the width of the branch middle section 122. The perimeter of the basket stent 10 located in the branch middle section 122 after the basket stent 10 is deployed can be calculated based on the spacing between each branch stent 12, the number of branch stents 12 and the width of the branch middle section 122. The basket stent 10 is located in the branch middle section 122 and abuts against the airway wall 30, so the perimeter of the basket stent 10 located in the branch middle section 122 can be approximately considered as the size of the airway.

[0085] In addition, the impedance measured by the first electrode group and the second electrode group can also provide guidance for completing the entire circle ablation of the airway wall, that is, according to the impedance measured by the first electrode group and the impedance measured by the second electrode group, the shape information of the ablation focus 60 is determined, and according to the shape information of the ablation focus 60 and the distance between the branch stents 12, it is judged whether supplementary ablation is needed, and when supplementary ablation is needed, the supplementary ablation position and the catheter rotation angle are obtained.

[0086] Usually, when the pulse energy parameters (voltage, pulse width, pulse spacing, etc.), electrode size, and electrode spacing are determined, the electric field formed in the same homogeneous environment is determined, so the morphological information of the ablation lesion 60 formed on the uniform continuous tissue (shape, length, surface width, depth, etc. of the ablation lesion 60) is also determined. Ideally, when pulse ablation is performed in the airway using the first electrode group located on different branch stents 12 (the electrode size of the first electrode group and the spacing between the electrodes 20 are fixed), the morphology of the ablation lesions 60 formed in various places is theoretically consistent. Combined with the spacing information between the branch stents 12 determined by the second electrode group, the distribution of the ablation lesions 60 between any two branch stents 12 can be simulated and calculated and analyzed. When the spacing between the two branch stents 12 is large and effective ablation of the entire circle cannot be guaranteed, appropriate prompts and suggestions can be made, including whether additional ablation is needed, the additional ablation position, and the required torsion angle of the catheter.

[0087] For example, the ablation focus 60 of the first electrode group with a fixed distance a is as follows: Figure 7 As shown, the ablation size, such as width and depth, can be determined. After the system impedance detection, the impedance of the second electrode group can be determined, and the distance b of the second electrode group can be calculated according to the relationship between the electrode spacing a and the impedance. Comparing the average width of the ablation focus 60 of the first electrode group and the distance b of the second electrode group 25, if the average width of the ablation focus 60 is smaller than b, it means that the full circle ablation has not been achieved. At this time, the system will prompt for additional ablation, and the appropriate rotation angle needs to be adjusted according to the size of the ablation focus 60 until the full circle ablation is achieved.

[0088] In addition, the lung ablation catheter of this embodiment measures impedance or bioelectric signals through the first electrode group and the second electrode group, so that the lung ablation catheter has two functions of mapping and ablation, and its discharge mode can also select single-rod (one branch stent 12) or inter-rod (between two branch stents 12) discharge. When single-rod discharge, the distance between the electrodes 20 is small, the mapping result is accurate, and precise ablation can be achieved. Inter-rod discharge can also be selected according to the location and size of the lesion.

[0089] Embodiment 2

[0090] A lung ablation catheter. The difference between this embodiment and the above-mentioned embodiment 1 is that the branch distal segment 121 includes more than two arms 1211, one end of the more than two arms 1211 is respectively connected to the distal fixing part 11 and arranged at intervals, and the other end is connected to the corresponding branch middle segment 122.

[0091] The number of arms 1211 can be set according to actual use requirements, such as two or more. Designing the branch distal end section 121 of the branch stent 12 as a multi-arm structure can increase the stability of the branch stent 12, so that when the basket stent 10 continues to expand, the branch stent 12 will not slide to both sides to avoid affecting the treatment effect.

[0092] When the branch distal end section 121 is not provided with a multi-arm structure, such as the lung ablation catheter of the first embodiment, Figure 8 and Fig. 9 As shown, when the inner diameter of the airway is much smaller than the equatorial diameter of the expanded basket stent 10 (that is, the maximum diameter of the branch middle section 122), the basket stent 10 can be further expanded after it is attached to the airway wall 30. At this time, if the basket stent 10 continues to be expanded, the branch stents 12 will slide to both sides on the smooth airway wall 30 due to insufficient movement space, causing the spacing between the branch stents 12 to change. The branch stents 12 are no longer evenly spaced. When the ablation mode is inter-rod discharge between two branch stents 12, the spacing between the electrodes 20 on the two branch stents 12 changes, which will directly affect the conduction and distribution of energy, thereby changing the treatment effect of the preset parameters and even causing damage.

[0093] In order to solve the above problems, this embodiment improves the branch bracket 12 on the basis of forming a special shape when the basket bracket 10 is unfolded, and designs the branch distal end section 121 as a multi-arm 1211 structure to increase the stability of the branch bracket 12. For example, Fig.10 and Fig.11 As shown, there are two arms 1211 of the branch distal section 121, and the two arms 1211 are connected to the distal fixing portion 11 and are arranged at intervals. The two arms 1211 and the distal fixing portion 11 can form a stable triangular structure to increase the stability of the branch support 12, so that when the basket support 10 continues to expand, the branch support 12 will not slide to both sides to avoid affecting the treatment effect. This embodiment does not limit the specific number of arms 1211. In actual application, the number of arms 1211 can be set to two or more according to needs.

[0094] Embodiment 3

[0095] A pulmonary ablation catheter. The difference between this embodiment and the above-mentioned embodiment 1 or embodiment 2 is that the stiffness of the branch distal segment 121 is less than or equal to the stiffness of the branch proximal segment 123, so that when the basket support 10 is unfolded, the deformation of the branch distal segment 121 is greater than or equal to the deformation of the branch proximal segment 123.

[0096] like Fig.12As shown, during clinical operations, the ablation catheter needs to cooperate with the bronchoscope 40 for clinical operations. Usually, the ablation catheter is first inserted into the working channel 41 of the bronchoscope 40. After the bronchoscope 40 is inserted into the airway and guided into place, the ablation catheter is then extended out of the outlet of the working channel 41. The state of the ablation catheter is judged by directly observing the images captured by the camera 50 and operations are performed. Therefore, the observation point of the camera 50 is usually located at the proximal end of the basket stent 10. However, the proximal segment 123 of the branches of the bulging basket stent 10 easily obstructs the field of view, making it impossible to completely observe the distal segment 121 of the branches of the basket stent 10, that is, the part close to the head end of the ablation catheter. The operator cannot accurately judge the position of the head end of the ablation catheter, which is extremely likely to cause harm.

[0097] To solve this problem, in this embodiment, on the basis of the structure of the basket stent 10 in the above-mentioned Embodiment 1 and Embodiment 2, further improvements are made to achieve the retraction of the head end of the ablation catheter, avoiding the appearance of a blind spot in the field of view, so that the most distal part observed by the operator in the image is the most distal part of the ablation catheter. The structure of the basket stent 10 in this embodiment after expansion is as Fig.13 shown. This structure is achieved based on the difference in stiffness of different segments of the branch stent 12. One implementation method is to use a shape memory alloy with segmented stiffness. The stiffness of the distal segment 121 of the branch is D1, the stiffness of the middle segment 122 of the branch is D2, and the stiffness of the proximal segment 123 of the branch is D3, where D1 < D3 < D2. When the basket stent 10 is expanded under force, the deformation of the distal segment 121 of the branch is the largest, causing the head end of the distal segment 121 of the branch to retract to avoid the appearance of a blind spot in the field of view; or the same effect can be achieved by heat setting with a memory material.

[0098] The structure of this embodiment can not only solve the problem of the blind spot in the field of view, but also achieve the self-expansion effect of the basket stent 10. As Fig.14 shown, when the basket stent 10 of Embodiment 1 is expanded, the angle A between the distal segment 121 of the branch and the extension line of the proximal-distal center line of the basket stent 10 is generally greater than 90 degrees. If the size of the airway is smaller than the maximum size of the basket stent 10 after expansion, when the branch stent 12 abuts against the airway wall 30 and further expands the basket stent 10, due to the lack of sufficient deformation space in the direction perpendicular to the airway wall 30, it will cause the branch stent 12 to slide to both sides (as Fig. 9 shown), resulting in the problem of uneven spacing of the branch stents 12.

[0099] When using the structure of the basket stent 10 of this embodiment, after the middle segment 122 of the branch abuts against the airway wall 30, the basket stent 10 can continue to expand to make the head end (distal end) retract, as Fig.15As shown, the angle A between the branch distal segment 121 and the extension line of the proximal and distal center line of the basket stent 10 is less than 90 degrees, and the branch distal segment 121, the branch middle segment 122, the branch proximal segment 123 and the central axis form a double-link elastic structure similar to a parallelogram; when the airway size is small and the branch stent 12 is subjected to an inward compression force, the structure can cause the branch stent 12 to deform in a direction perpendicular to the airway wall 30, and at this time the angle A is reduced, avoiding the lateral slippage of the branch stent 12 and causing the branch stent 12 to have uneven spacing. The ablation catheter of this structure can greatly increase the range of airway sizes that can be adapted, and the spacing of the branch stents 12 can always be kept uniform regardless of the airway size. At the same time, the double-link structure formed by the inward retraction of the ablation catheter head end has a certain elasticity, and when the airway compresses the branch stent 12 to deform inward, it also provides a reaction force to the airway wall 30 to ensure the effective contact of the branch middle segment 122.

[0100] Embodiment 4

[0101] A pulmonary ablation catheter, this embodiment is based on the above-mentioned embodiment 1 or embodiment 2 or embodiment 3, such as Fig.16 As shown, the basket bracket 10 also includes a plurality of connecting segments 14, and each branch bracket 12 is connected to one end away from the distal fixing portion 11 with a connecting segment 14, and the width of the branch bracket 12 is smaller than the width of the connecting segment 14, so that the distance between two adjacent branch brackets 12 is smaller than the distance between two adjacent connecting segments 14, so that the plurality of connecting segments 14 can be easily deformed and installed in the proximal fixing portion 13.

[0102] Furthermore, it also includes a central rod 15, the central rod 15 passes through the center of the basket support 10, the distal fixing portion 11 is fixed to one end of the central rod 15, and the proximal fixing portion 13 is movably connected to the other end of the central rod 15. The central rod 15 and the central axis of the basket support 10 are located on the same straight line, and the proximal fixing portion 13 moves on the central rod 15 so that the basket support 10 is forced to unfold. The central rod 15 can play a guiding role, so that the proximal fixing portion 13 of the basket support 10 moves along the central rod 15, preventing the central axis of the basket support 10 from deviating when the basket support 10 is unfolded, and playing a limiting role in the unfolding of the basket support 10.

[0103] Embodiment 5

[0104] An ablation system, such as Fig.12 As shown, it includes a bronchoscope 40, a camera 50 and the lung ablation catheter described in any one of the above embodiments one to four, a working channel 41 is provided in the bronchoscope 40, the camera 50 is arranged at the distal end of the bronchoscope 40, and the lung ablation catheter is arranged in the working channel 41.

[0105] The lung ablation catheter needs to be used in conjunction with the bronchoscope 40 for clinical operations. Usually, the lung ablation catheter is first inserted into the working channel 41 of the bronchoscope 40. After the bronchoscope 40 is inserted into the airway and guided into place, the lung ablation catheter is extended out of the exit of the working channel 41. The status of the lung ablation catheter is judged and the operation is performed by direct observation of the image captured by the camera 50.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A pulmonary ablation catheter, characterized in that: include: The basket support comprises a plurality of branch supports arranged at intervals along the circumferential direction, the distal ends of the plurality of branch supports are respectively gathered together, the proximal ends of the plurality of branch supports are respectively gathered together, and the branch supports are sequentially divided into a branch distal end section, a branch middle section and a branch proximal end section along the distal to proximal direction; a catheter assembly, the main body section of which is connected to the proximal end of the basket stent; A plurality of electrodes, wherein two or more electrodes are arranged at intervals on the middle section of each branch; The basket support is controlled by the catheter assembly to have a contracted state and an expanded state. In the expanded state, the deformation of the middle section of the branch is smaller than the deformation of the distal section of the branch and the proximal section of the branch. The middle section of the branch is parallel to the central axis of the basket support so that the electrode fits against the airway wall of the lungs.

2. A pulmonary ablation catheter according to claim 1, characterized in that: The basket support also includes a distal fixing part and a proximal fixing part. The distal ends of a plurality of branch supports converge and are connected to the distal fixing part, the proximal ends of a plurality of branch supports converge and are connected to the proximal fixing part, and the catheter assembly is connected to the proximal fixing part.

3. A pulmonary ablation catheter according to claim 1, characterized in that: The material of the branch support is formed by shaping a memory alloy so that the rigidity of the middle section of the branch is greater than the rigidity of the distal section of the branch and the proximal section of the branch.

4. A pulmonary ablation catheter according to claim 1, characterized in that: The cross-sectional area of ​​the middle section of the branch is greater than the cross-sectional area of ​​the distal section of the branch and the proximal section of the branch; or the thickness of the middle section of the branch along the expansion-contraction direction is greater than the thickness of the distal section of the branch and the proximal section of the branch along the expansion-contraction direction.

5. A pulmonary ablation catheter according to claim 1, characterized in that: The minimum radial thickness of the basket support in the middle section of the branch is greater than the maximum radial thickness of the basket support in the distal section of the branch and the proximal section of the branch, wherein the radial thickness of the basket support is the thickness of the basket support along the expansion-contraction direction.

6. A pulmonary ablation catheter according to claim 3, characterized in that: The rigidity of the branch distal end section is less than or equal to the rigidity of the branch proximal end section, so that when the basket support is unfolded, the deformation of the branch distal end section is greater than or equal to the deformation of the branch proximal end section.

7. A pulmonary ablation catheter according to claim 6, characterized in that: When the basket support is unfolded, the angle between the distal end section of the branch and the extended line of the line connecting the proximal and distal centers of the basket support is less than 90 degrees.

8. A pulmonary ablation catheter according to claim 2, characterized in that: The branch distal section includes more than two arms, one end of the two or more arms is respectively connected to the distal fixing portion and arranged at intervals, and the other end is connected to the corresponding branch middle section.

9. The pulmonary ablation catheter according to claim 1, characterized in that: The plurality of branch brackets include a first branch bracket and a second branch bracket that are spaced apart from each other, a first electrode and a second electrode are distributed on the first branch bracket, and the first electrode and the second electrode form a first electrode group; A third electrode is distributed on the second branch support. The third electrode and the first electrode are located at the same radial cross section of the basket support. The first electrode and the third electrode form a second electrode group.

10. The pulmonary ablation catheter according to claim 2, characterized in that: The basket bracket also includes multiple connecting segments, and the proximal end of each branch bracket is connected to a connecting segment. The width of the branch bracket is smaller than the width of the connecting segment, so that the distance between two adjacent branch brackets is smaller than the distance between two adjacent connecting segments, and multiple connecting segments are fixed to the proximal fixing part.

11. A pulmonary ablation catheter according to claim 2, characterized in that: It also includes a central rod, which passes through the center of the basket support. The distal fixing portion is fixed to one end of the central rod, and the proximal fixing portion is movably connected to the other end of the central rod.

12. The pulmonary ablation catheter according to claim 1, characterized in that: The branch distal segment, the branch middle segment and the branch proximal segment are split structures.

13. A detection method using the pulmonary ablation catheter according to claim 9, characterized in that: include: According to the impedance measured by the first electrode group and the impedance measured by the second electrode group, it is determined whether the shape of the basket support after being unfolded is normal and whether the state of the electrodes is normal.

14. The method for detecting a pulmonary ablation catheter according to claim 13, characterized in that: Also includes: The distance between the first branch support and the second branch support is calculated according to the impedance measured by the first electrode group, the distance between the first electrode and the second electrode, and the impedance measured by the second electrode group.

15. The method for detecting a pulmonary ablation catheter according to claim 14, characterized in that: Also includes: The size of the airway in contact with the middle section of the branch is calculated based on the distance between each branch support when the basket support is in contact with the airway wall, the number of the branch supports and the width of the middle section of the branch.

16. The method for detecting a pulmonary ablation catheter according to claim 14, characterized in that: Also includes: The ablation focus shape information is determined based on the impedance measured by the first electrode group and the impedance measured by the second electrode group, and whether supplementary ablation is needed is judged based on the ablation focus shape information and the distance between the branch stents. When supplementary ablation is needed, the supplementary ablation position and the catheter rotation angle are obtained.

17. An ablation system, characterized in that: It comprises a bronchoscope, a camera and the lung ablation catheter according to any one of claims 1 to 12, wherein a working channel is provided in the bronchoscope, the camera is arranged at the distal end of the bronchoscope, and the lung ablation catheter is arranged in the working channel.

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