Cryoablation catheter and system

Abstract

The utility model relates to a cryoablation catheter and system, the ablation catheter comprises a vacuum tube with a near end and a far end, and the near end of the vacuum tube is connected with a vacuum joint; a woven bracket is fixed at the far end of the vacuum tube; an air inlet channel and an air return channel are arranged in the vacuum tube, the far end of the vacuum tube extends out of the far end of the vacuum tube and spirally surrounds and is fixed to the woven stent in the axial direction of the woven stent, the far end of the air inlet channel is in fluid communication with the far end of the air return channel, and the air inlet channel and the air return channel extending out of the far end of the vacuum tube form a freezing area; the outer sides of the vacuum tube and the woven stent are further sleeved with a conveying sheath tube, the conveying sheath tube and the vacuum tube can relatively move in the axial direction, and when the woven stent is moved out of the conveying sheath tube, the woven stent is self-expanded and unfolded in a preset shape so as to drive the frozen area to be attached to the target tissue. The cryoablation catheter and system are wide in application range and high in ablation efficiency, and blood flow cannot be blocked when the cryoablation catheter and system are applied to ablation in blood vessels.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to a cryoablation catheter and system. Background Art

[0002] Cryoablation uses a low-temperature medium to lower the temperature of the target ablation site (lesioned tissue), destroying the tissue cells and achieving the therapeutic goal. Currently, cryoablation is widely used not only in the treatment of atrial fibrillation (AF), but also in the treatment of renal artery sympathetic nerves, tumors, arterial vessels, and pulmonary hypertension.

[0003] Traditional cryoablation balloon catheters mainly fill the balloon with refrigerant to cool the balloon and take away the heat around the balloon to achieve the purpose of freezing cells to death. When ablating tissues in blood vessels, in order to achieve a better cryoablation effect, the balloon needs to be filled and close to the blood vessel wall during cryoablation to block the flow of blood. For example, when using a cryoablation balloon to ablate blood vessels such as the pulmonary artery, renal artery and branch arteries, since there is no other blood vessel compensation, the blood vessel occlusion time is too long, which will cause severe distal ischemia and other consequences. Moreover, the blood blockage time is too long and will also lead to thrombosis. The blockage will also cause excessive local blood vessel pressure, causing blood vessel rupture, leading to bleeding complications, etc. In addition, traditional cryoablation balloon catheters cannot fit well in tortuous blood vessels, affecting the ablation effect. Summary of the Invention

[0004] Based on this, the present application provides a cryoablation catheter and system that has a wide range of applications, high ablation efficiency, and does not block blood flow when used for intravascular ablation.

[0005] In one aspect, an embodiment of the present application provides a cryoablation catheter, comprising a vacuum tube having a proximal end and a distal end, wherein the proximal end of the vacuum tube is connected to a vacuum connector for evacuating the vacuum tube; and a braided stent is fixed to the distal end of the vacuum tube;

[0006] An air inlet passage and an air return passage are provided inside the vacuum tube, and distal ends of the air inlet passage and the air return passage extend out of the distal end of the vacuum tube and are spirally wound around the braided stent along the axial direction of the braided stent and fixed to the braided stent. The distal end of the air inlet passage is in fluid communication with the distal end of the air return passage, and the air inlet passage and the air return passage extending out of the distal end of the vacuum tube constitute a freezing area;

[0007] The proximal end of the vacuum tube is also provided with an air intake connector and an air return connector which are fluidically connected to the air intake passage and the air return passage respectively; the outside of the vacuum tube and the braided stent is also provided with a delivery sheath, and the delivery sheath and the vacuum tube can move relative to each other in the axial direction. When the braided stent is removed from the delivery sheath, the braided stent self-expands in a predetermined shape and drives the freezing area to fit the target tissue.

[0008] In an optional embodiment, the freezing area further includes a heat insulating mechanism, which is located on a side of the air inlet passage and the air return passage facing away from the target tissue.

[0009] In an optional embodiment, the thermal insulation mechanism is a vacuum chamber, and the proximal end of the vacuum chamber is in fluid communication with the vacuum joint or the proximal end of the vacuum chamber is in fluid communication with the inner cavity of the vacuum tube.

[0010] In an optional embodiment, the thermal insulation mechanism is a thermal insulation coating, and the thermal insulation coating is provided on the outer surface of the air inlet passage and the air return passage on a side facing away from the target tissue.

[0011] In an optional embodiment, the braided stent includes a diameter-reducing section located at the proximal end of the braided stent and a straight section located at the distal end of the braided stent, and the freezing area is located in the straight section.

[0012] In an optional embodiment, the braiding density of the diameter-changing section is smaller than the braiding density of the straight section.

[0013] In an optional embodiment, the freezing area is fixed by mixed weaving with the braided stent.

[0014] In an optional embodiment, the ablation temperature of the cryoablation catheter can be adjusted by controlling the diameter of the air inlet passage.

[0015] In an optional embodiment, the air intake passage and the air return passage are an integrated structure.

[0016] On the other hand, an embodiment of the present application provides a cryoablation system, including a cryoablation device and the above-mentioned cryoablation catheter, wherein the cryoablation catheter is connected to the cryoablation device via a connector, and is used to transport the refrigerant in the cryoablation device to the freezing area of ​​the freezing tube through the air inlet connector, and perform cryoablation.

[0017] Compared with the prior art, the advantages of the embodiments of the present application are:

[0018] 1. In the embodiment of the present application, the braided stent is a tubular mesh structure, and the freezing pipe is spirally wrapped around and fixed to the braided stent. During cryoablation, the mesh of the hollow braided stent can allow blood to pass through, avoiding the risk of blocking blood flow caused by the use of a balloon structure in the prior art; in addition, the braiding density of the variable diameter section of the braided stent is less than the braiding density of the straight section, that is, the mesh of the variable diameter section is larger, which is more conducive to blood flow and further reduces the risk of blood flow blockage.

[0019] 2. The present application also provides a vacuum chamber in the freezing area. The vacuum chamber is located on the side away from the target tissue, which can isolate the heat transfer between the refrigerant and the blood, thereby preventing the temperature of the refrigerant from being carried away by the blood flow. The setting of the vacuum chamber enables the freezing energy to be transferred to the target tissue side, reducing energy loss and improving freezing efficiency. At the same time, it can also avoid the phenomenon of freezing caused by the lowering of blood temperature during the cryoablation process.

[0020] 3. In the embodiment of the present application, the braided stent is made of superelastic materials such as nickel-titanium alloy and cobalt-chromium alloy, which can conform to blood vessels of various shapes, thereby increasing the application range of the product. Moreover, the arrangement of the variable diameter section and the straight section makes the braided stent more conformable, and it can not only conform to blood vessels of different diameters, but also fit blood vessels with curved shapes or bifurcations.

[0021] 4. The cooling pipeline in the embodiment of the present application is made of metal alloy, which has higher pressure resistance than the cryoablation balloon catheter, thereby improving the safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic structural diagram of a cryoablation catheter according to one embodiment of the present application.

[0023] Figure 2 This is a schematic structural diagram of a cryoablation catheter according to another embodiment of the present application.

[0024] Figure 3 This is a schematic structural diagram of a woven mesh according to an embodiment of the present application.

[0025] Figure 4 This is a schematic cross-sectional view of a braided stent according to an embodiment of the present application.

[0026] Figure 5a This is a cross-sectional schematic diagram of an air intake passage and a vacuum chamber according to another embodiment of the present application.

[0027] Figure 5b This is a cross-sectional schematic diagram of an air intake passage and a vacuum chamber according to another embodiment of the present application.

[0028] Figure 6 This is a schematic diagram of a cryoablation catheter located at a bifurcated blood vessel according to one embodiment of the present application.

[0029] Figure 7 This is a schematic structural diagram of a cryoablation system according to an embodiment of the present application.

[0030] Reference numerals:

[0031] 100-cryoablation catheter; 200-cryoablation equipment;

[0032] 1-vacuum tube; 11-vacuum connector; 12-air inlet connector; 13-air return connector; 2-air inlet passage; 3-air return passage; 4-braided stent; 41-reducing section; 42-straight section; 5-freezing area; 51-vacuum chamber; 6-delivery sheath; 201-human-computer interaction module; 202-control module; 203-gas path module; 204-vacuum module. DETAILED DESCRIPTION

[0033] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0035] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0036] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0039] The technical solutions provided by the embodiments of the present application are described below with reference to the accompanying drawings.

[0040] The proximal end mentioned in this application refers to the end close to the surgical operator, and the distal end refers to the end far away from the surgical operator.

[0041] like Figures 1-6 As shown, the present application provides a cryoablation catheter 100, comprising a vacuum tube 1 having a proximal end and a distal end, wherein the proximal end of the vacuum tube 1 is connected to a vacuum connector 11 for evacuating the vacuum tube 1; thereby reducing the temperature loss of the refrigerant during transportation and improving the cooling efficiency.

[0042] A braided stent 4 is fixed to the distal end of the vacuum tube 1. An air inlet passage 2 and an air return passage 3 are provided within the vacuum tube 1. The distal ends of the air inlet passage 2 and the air return passage 3 extend beyond the distal end of the vacuum tube 1 and are helically secured to the braided stent 4 along the axial direction of the braided stent 4. The distal end of the air inlet passage 2 is in fluid communication with the distal end of the air return passage 3. The air inlet passage 2 and the air return passage 3 extending beyond the distal end of the vacuum tube 1 constitute a freezing zone 5, which is primarily used for ablating target tissue. An air inlet connector 12 and an air return connector 13 are also provided at the proximal end of the vacuum tube 1, respectively in fluid communication with the air inlet passage 2 and the air return passage 3. A delivery sheath 6 is sheathed around the exterior of the vacuum tube 1 and the braided stent 4. The delivery sheath 6 and the vacuum tube 1 are axially movable relative to each other. When the braided stent 4 is removed from the delivery sheath 6, the braided stent 4 self-expands into a predetermined shape, thereby driving the freezing zone 5 to conform to the target tissue.

[0043] In the embodiment of the present application, the air inlet connector 12 and the air return connector 13 are both connected to the cryoablation device to deliver refrigerant to the cryoablation catheter or recover refrigerant (such as N2, N2O, liquid nitrogen, etc.). The refrigerant in the cryoablation device enters the air inlet passage 2 through the air inlet connector 12. Since the distal end of the air inlet passage 2 is fluidly connected to the distal end of the air return passage 3, the refrigerant enters the air return passage 3 through the distal end of the air inlet passage 2 and is discharged from the air return connector 13. In this embodiment, the air inlet passage 2 and the air return passage 3 can be formed by two pipes connected together at the distal ends, or by a pipe that is relatively bent, that is, the air inlet passage 2 and the air return passage 3 are an integrated structure. Figure 1 In the figure, a relatively bent pipe is used as an example to illustrate that the pipe can be made of cobalt-chromium alloy, copper-nickel alloy or other materials that are resistant to low temperatures and flexible. It has strong pressure resistance, so that refrigerant with a pressure of not less than 1500psi can pass through the intake passage 2 and the return passage 3. It has high pressure resistance and improves the safety of the product.

[0044] In an optional embodiment, the ablation temperature of the cryoablation catheter can be adjusted by the diameter of the air inlet passage 2. For example, the larger the diameter of the air inlet passage 2, the greater the flow rate of the refrigerant flowing into the air inlet passage 2, and the lower the ablation temperature. Conversely, the smaller the diameter of the air inlet passage 2, the smaller the flow rate of the refrigerant flowing into the air inlet passage 2, and the higher the ablation temperature. In addition, the ablation temperature can also be controlled by the air inlet pressure. For example, the greater the air inlet pressure, the greater the flow rate of the refrigerant flowing into the air inlet passage 2, and the lower the ablation temperature. Conversely, the smaller the air inlet pressure, the smaller the flow rate of the refrigerant flowing into the air inlet passage 2, and the higher the ablation temperature. The control range of the ablation temperature of the cryoablation catheter in the embodiment of the present application is -10°C to -150°C.

[0045] The braided stent 4 is pre-installed in the delivery sheath 6 before the cryoablation catheter is used. Figure 2 As shown, when performing cryoablation, the distal end of the cryoablation catheter is first delivered to the site to be ablated under the guidance of the guide wire, and then the vacuum tube 1 is pushed forward or the delivery sheath 6 is pulled backward to remove the braided stent 4 from the delivery sheath 6. The braided stent 4 expands and unfolds in a predetermined shape, thereby driving the frozen area 5 to fit the target tissue. Figure 3 As shown, refrigerant is delivered and ablation is performed. After the ablation is completed, the refrigerant is discharged, and the braided stent 4 is contracted and withdrawn into the delivery sheath 6. Figure 2 In this embodiment, the refrigerant flows into the air inlet passage 2, and its cooling capacity is directly transferred to the target tissue. The cooling method is the Joule-Thomson effect, and the heat transfer satisfies the formula:

[0046] Q = k*A*ΔT / d.

[0047] Where Q represents the amount of heat transferred, k represents thermal conductivity, A represents area, ΔT represents the temperature difference, and d represents the distance between the refrigerant and the target tissue. It can be seen that heat transfer is inversely proportional to d; the greater the distance, the lower the heat transfer rate. However, the cryoablation catheter of the present application does not require an intermediate medium to transfer energy. The distance between the refrigerant and the target tissue is close to zero, meaning that the refrigerant's cooling energy is directly transferred to the target tissue, significantly improving efficiency.

[0048] In an optional embodiment, the outer surface of the vacuum tube 1 comes into contact with blood during the transportation of the ablation catheter, so a low-temperature resistant clear water coating can be provided on the outer surface of the vacuum tube 1. This not only makes the ablation catheter smoother during transportation, but also avoids the occurrence of icing and other phenomena.

[0049] The braided stent 4 in the embodiment of the present application can be a tubular mesh structure woven from a number of braided wires, for example: the braided wires can be 6-20, the wire diameter can be between 0.02mm-0.5mm, and the material can be a superelastic material such as nickel-titanium alloy, cobalt-chromium alloy, etc. The molding method can make the stent have a predetermined shape by weaving, and then eliminate the stress of the material through heat treatment, and can expand rapidly after release, so that the stent has a predetermined shape in its natural state. Therefore, the braided stent 4 in this embodiment can conform to blood vessels of various shapes, and can also fit blood vessels at the bifurcation of blood vessels, thereby improving the application range of the product. Moreover, the braided stent 4 is a tubular mesh structure, and the freezing pipeline is spirally wrapped around and fixed to the braided stent 4. During cryoablation, the mesh at the proximal end of the braided stent 4 can be used for blood flow to pass through, avoiding the risk of blocking blood flow caused by using a balloon structure in the prior art.

[0050] In an optional embodiment, the freezing area 5 further includes an insulation mechanism, which is located on the side of the air inlet passage 2 and the air return passage 3 away from the target tissue. Optionally, the insulation mechanism can be a vacuum chamber 51, which is located on the side of the air inlet passage 2 and the air return passage 3 away from the target tissue. Figure 4 , the distal ends of the air inlet passage 2 and the air return passage 3 are located on the side close to the target tissue; the proximal end of the vacuum chamber 51 is in fluid communication with the vacuum connector 11 or the proximal end of the vacuum chamber 51 is in fluid communication with the inner cavity of the vacuum tube 1. In other embodiments, the thermal insulation mechanism may also be a thermal insulation coating, which is provided on the outer surface of the air inlet passage 2 and the air return passage 3 on the side away from the target tissue. The thermal insulation mechanism in this embodiment is located on the side away from the target tissue, which can isolate the refrigerant from the heat transfer with the blood, thereby preventing the temperature of the refrigerant from being carried away by the blood flow, and transferring the freezing energy to the target tissue side, reducing energy loss, and improving freezing efficiency. At the same time, it can also prevent the temperature of the blood from dropping and freezing due to the cryoablation process.

[0051] The cross-sections of the air inlet passage 2, the air return passage 3 and the vacuum chamber 51 in the embodiment of the present application may be semicircular, such as Figure 4 As shown in , it can also be a semi-elliptical or rounded rectangle, such as Figure 5a and Figure 5b As shown in . It can also be other shapes, which can be set according to actual needs.

[0052] In another optional embodiment, the braided stent 4 includes a diameter-reducing section 41 located at the proximal end of the braided stent 4 and a straight section 42 located at the distal end of the braided stent 4, and the freezing area 5 is located in the straight section 42. Figure 3 The variable diameter section 41 in this embodiment is trumpet-shaped. The variable diameter section 41 starts from the proximal end of the braided stent 4 and gradually increases in diameter. When the diameter reaches the target value, it enters the straight section 42. The straight section 42 is in a tubular network shape, which is convenient for fitting with the blood vessel wall, thereby making the freezing area 5 fit the target tissue. The arrangement of the variable diameter section 41 and the straight section 42 makes the braided stent 4 more adaptable. It can not only adapt to blood vessels of different diameters, but also fit blood vessels with curved shapes or bifurcations, such as Figure 6 As shown in , the scope of application is expanded.

[0053] In an optional embodiment, the braiding density of the variable diameter section 41 is smaller than the braiding density of the straight section 42. For example, the PPI (Pores Per Linear Inch) of the variable diameter section 41 may be in the range of 5-50, and the PPI of the straight section 42 may be in the range of 20-100. That is, the mesh of the variable diameter section 41 is larger, which is more conducive to blood flow and further reduces the risk of blood flow blockage. Figure 3, Figure 3 The middle arrow points to the direction of blood flow.

[0054] In this embodiment, the freezing region 5 can be secured by a mixed braiding method with the braided support 4. For example, the braiding method can be one of 1-on-2, 1-on-1, or 2-on-2, depending on the pressure it can withstand. In other embodiments, the freezing region 5 can also be secured to the outer surface of the braided support 4 by welding, adhesive dispensing, clamps, or other methods.

[0055] Another aspect of the present application provides a cryoablation system, referring to Figure 7 , including a cryoablation device 200 and the above-mentioned cryoablation catheter 100, the cryoablation catheter 100 is connected to the cryoablation device 200 through a connector, and is used to transport the refrigerant in the cryoablation device 200 to the freezing area 5 of the freezing tube through the air inlet connector 12, and perform cryoablation.

[0056] Specifically, the cryoablation device 200 in this embodiment includes a human-computer interaction module 201, a control module 202, an air circuit module 203 and a vacuum module 204. The human-computer interaction module 201 is electrically connected to the control module 202, and the control module 202 is electrically connected to the air circuit module 203 and the vacuum module 204 respectively. The air circuit module 203 can be connected to the air inlet connector 12 and the air return connector 13 on the cryoablation catheter 100 through connectors, respectively, for delivering refrigerant to the cryoablation catheter 100 or recovering refrigerant. The vacuum module 204 is connected to the vacuum connector 13 on the cryoablation catheter 100. During operation, the cryoablation device 200 is first started, and the cryoablation catheter 100 is operated to enter the patient's body. Then, the vacuum tube is pushed forward or the delivery sheath 6 is pulled backward to move the braided stent 4 out of the delivery sheath 6. The braided stent 4 expands and unfolds in a predetermined shape, thereby driving the freezing area 5 to fit the target tissue. The control module 202 controls the vacuum module 204 to vacuum the vacuum tube 1, and then the control module 202 controls the gas circuit module 203 to start delivering refrigerant to the cryoablation catheter 100, starting the ablation operation. The ablation parameters are returned to the control module 202, processed by the control module 202 and finally fed back to the human-computer interaction module 201. After the ablation is completed, the control module 202 is operated to make the gas circuit module 203 stop delivering the refrigerant and discharge the refrigerant. The braided stent 4 shrinks and withdraws into the delivery sheath 6, and then withdraws it from the human body together.

[0057] The above is an exemplary description of a cryoablation system. In actual applications, the cryoablation device may also adopt other technical means in the prior art, which will not be described in detail here.

[0058] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A cryoablation catheter, characterized in that: The vacuum tube comprises a proximal end and a distal end, wherein the proximal end of the vacuum tube is connected to a vacuum joint for evacuating the vacuum tube; and the distal end of the vacuum tube is fixed with a braided stent; An air inlet passage and an air return passage are provided inside the vacuum tube, and distal ends of the air inlet passage and the air return passage extend out of the distal end of the vacuum tube and are spirally wound around the braided stent along the axial direction of the braided stent and fixed to the braided stent. The distal end of the air inlet passage is in fluid communication with the distal end of the air return passage, and the air inlet passage and the air return passage extending out of the distal end of the vacuum tube constitute a freezing area; The proximal end of the vacuum tube is further provided with an air intake joint and an air return joint which are in fluid communication with the air intake passage and the air return passage respectively; A delivery sheath is also provided on the outside of the vacuum tube and the braided stent. The delivery sheath and the vacuum tube can move relative to each other in the axial direction. When the braided stent is removed from the delivery sheath, the braided stent self-expands in a predetermined shape and drives the frozen area to fit the target tissue.

2. The cryoablation catheter according to claim 1, characterized in that The freezing area further includes a heat insulating mechanism, which is located on a side of the air inlet passage and the air return passage facing away from the target tissue.

3. The cryoablation catheter according to claim 2, characterized in that The thermal insulation mechanism is a vacuum cavity, and the proximal end of the vacuum cavity is in fluid communication with the vacuum joint or the proximal end of the vacuum cavity is in fluid communication with the inner cavity of the vacuum tube.

4. The cryoablation catheter according to claim 2, characterized in that The heat-insulating mechanism is a heat-insulating coating, and the heat-insulating coating is provided on the outer surface of the air inlet passage and the air return passage on a side away from the target tissue.

5. The cryoablation catheter according to claim 1, characterized in that The braided stent comprises a diameter-reducing section located at the proximal end of the braided stent and a straight section located at the distal end of the braided stent, and the freezing area is located in the straight section.

6. The cryoablation catheter according to claim 5, characterized in that The braiding density of the diameter-changing section is smaller than the braiding density of the straight section.

7. The cryoablation catheter according to claim 1, characterized in that The freezing area is fixed by mixed weaving with the braided support.

8. The cryoablation catheter according to claim 1, characterized in that The ablation temperature of the cryoablation catheter can be adjusted by controlling the diameter of the air inlet passage.

9. The cryoablation catheter according to claim 1, characterized in that The air intake passage and the air return passage are an integrated structure.

10. A cryoablation system, characterized in that: It comprises a cryoablation device and a cryoablation catheter as described in any one of claims 1 to 9, wherein the cryoablation catheter is connected to the cryoablation device via a connector, and is used to transport the refrigerant in the cryoablation device to the freezing area of ​​the cryoablation catheter via the air inlet connector, and perform cryoablation.

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