A cryoballoon catheter

Abstract

The present application provides a cryoballoon catheter, comprising: an inner balloon and an outer balloon, wherein the inner balloon is located inside the outer balloon, and a supporting medium is provided in the inner balloon, the supporting medium being convertible between solid and liquid states; a cryocavity is formed between the outer and inner balloons, the cryocavity comprising an inlet and an outlet, wherein the refrigerant enters the cryocavity from the inlet, transfers heat with the outside, and then vaporizes and flows out from the outlet. The present application changes the supportive properties of the inner balloon by arranging a phase change of the medium in the inner balloon, that is, using a solid medium as a support base in the working state, so that the refrigerant used for heat transfer is closely attached to the outer balloon, enabling more efficient heat transfer with the lesion, freezing a large area of ​​lesions, and saving surgical time.

Description

Technical Field

[0001] The present application relates to the field of medical devices, and in particular to a cryoballoon catheter. Background Art

[0002] With the advancement of technology, the concept of "minimally invasive surgery" has penetrated into all areas of surgery. Minimally invasive surgery refers to surgery performed using modern medical devices such as laparoscopes and cystoscopes and related equipment. Compared with traditional surgery, minimally invasive surgery offers significant advantages such as smaller incisions, less pain, faster recovery, shorter hospital stays, and less blood loss.

[0003] Among them, medical catheters are common minimally invasive medical surgical instruments. According to the needs of the disease, some medical surgical catheters can reach the lesions through the natural cavities of the human body (airways, blood vessels, etc.) and perform targeted treatments on them. The treatment form is usually to achieve the treatment of the lesions through some kind of energy (such as ultra-low temperature, etc.). For example, a freezing catheter that uses low-temperature liquid nitrogen as an energy source continuously transfers heat to the tumor lesions during surgery to treat bladder tumors. During this period, a certain volume of ice balls will be generated to cover the lesions to achieve the purpose of treatment. This heat exchange treatment principle often limits the range of energy.

[0004] In the prior art, the size of the ice ball produced by cryotherapy depends to a certain extent on the size of the balloon. In the existing catheter design, the liquid nitrogen nozzle is set at the center of the balloon so that the liquid nitrogen can be sprayed evenly. When the balloon radius is small, the liquid nitrogen can fill the entire balloon, and the temperature of the balloon wall is close to the temperature of the balloon center. However, when the balloon size increases to a certain extent, the liquid nitrogen has undergone a lot of heat exchange in the process from the nozzle to the balloon wall, causing the temperature of the liquid nitrogen reaching the balloon wall to rise or even vaporize, resulting in the size of the ice ball produced by the contact between the balloon wall and the lesion being limited, and unable to cover lesions with a larger area or a larger number. Multiple freezing is required to achieve the desired treatment effect, which will consume more liquid nitrogen and prolong the operation time.

[0005] Accordingly, the present application provides a double-layer balloon design that, regardless of balloon size, can utilize a solid support medium as a support base during operation, allowing the refrigerant used for freezing to adhere closely to the balloon wall, thereby reducing heat loss from the refrigerant within the balloon. Existing double-layer balloon designs are mostly designed for safety reasons, aiming to prevent high-pressure explosions and balloon rupture. CN117695538A discloses a double-layer balloon with a pressure sensor and a liquid sensor installed between the inner and outer sub-balloons, enabling real-time monitoring of the medical balloon and facilitating adjustments to surgical procedures based on balloon rupture. Other double-layer balloon designs are designed for purposes such as convenient drug administration. Currently, no double-layer balloon has been designed to address the aforementioned technical issues. Summary of the Invention

[0006] The present application provides a cryoballoon catheter, which adopts a double-layer balloon design. Regardless of the size of the balloon, it can use a solid supporting medium as a supporting basis during operation, so that the refrigerant used for freezing is close to the balloon wall, reducing the heat loss of the refrigerant inside the balloon and expanding the range of action of the refrigerant on the lesion.

[0007] The present application provides a cryoballoon catheter, comprising: an inner balloon and an outer balloon, wherein the inner balloon is located inside the outer balloon, and a supporting medium is provided in the inner balloon, wherein the supporting medium can be converted between solid and liquid states;

[0008] A freezing cavity is formed between the outer balloon and the inner balloon. The freezing cavity includes an inlet and an outlet. After the refrigerant enters the freezing cavity from the inlet and conducts heat transfer with the outside, it flows out from the outlet.

[0009] Optionally, the supporting medium in the inner balloon is a high freezing point liquid, and the high freezing point liquid becomes solid after heat transfer by the refrigerant.

[0010] Optionally, it further includes: a liquid inlet tube, which is arranged in the inner layer balloon, and has a liquid inlet hole, and the high freezing point liquid flows into the liquid inlet hole to fill the inner layer balloon.

[0011] Optionally, it also includes: a refrigerant tube, which is nested in the liquid inlet tube, and the refrigerant tube axially penetrates from the inner layer balloon into the freezing cavity, and the section of the refrigerant tube extending into the freezing cavity includes the inlet; or, the refrigerant tube and the liquid inlet tube are arranged in parallel, and the refrigerant tube axially penetrates from the inner layer balloon into the freezing cavity, and the section of the refrigerant tube extending into the freezing cavity includes the inlet.

[0012] Optionally, the inner balloon further includes a seal, which is wrapped around the refrigerant tube.

[0013] Optionally, the balloon around the refrigerant tube is ultrasonically welded or heat-melted to the refrigerant tube.

[0014] Optionally, the liquid inlet pipe is provided with at least one liquid inlet hole, and the liquid inlet holes are evenly distributed on the liquid inlet pipe.

[0015] Optionally, the supporting working fluid is an electrorheological fluid, the electrorheological fluid is connected to an external electric field generator, and the electrorheological fluid performs conversion between liquid and solid under the control of the external electric field generator.

[0016] Optionally, the supporting working medium is a magnetorheological fluid, the magnetorheological fluid is connected to an external magnetic field, and the magnetorheological fluid performs conversion between liquid and solid under the control of the external magnetic field.

[0017] Optionally, the tip of the outer balloon has a protective protrusion.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] 1. The present application provides an inner balloon that can be converted into a solid state. The inner balloon uses a solid supporting medium as its support base, so that the refrigerant used for freezing is close to the wall of the outer balloon. The refrigerant in the outer balloon reduces heat loss inside the balloon and can transfer heat to the lesion more efficiently, thereby freezing a large area of ​​lesions and saving surgical time.

[0020] 2. The present application places a high-freezing-point liquid in the outer balloon, so that the high-freezing-point liquid in the inner balloon is converted into a solid state under the action of the refrigerant in the outer balloon. The outer balloon converted into a solid state can provide support for the outer balloon, and the refrigerant in the outer balloon is pressed tightly to the balloon wall to be close to the lesion, thereby achieving more efficient heat transfer. The high-freezing-point liquid makes this technical solution more cost-effective and easy to implement.

[0021] 3. In the present application, the liquid inlet tube for delivering high-freezing-point liquid to the inner balloon and the refrigerant tube for delivering refrigerant to the outer balloon are nested, thereby simplifying the internal structure of the balloon and saving space.

[0022] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] Figure 1 Shown is a cross-sectional view of a cryoballoon catheter according to one embodiment of the present application.

[0025] Figure 2 Shown is a cross-sectional view of a cryoballoon catheter according to yet another embodiment of the present application.

[0026] Figure 3 Shown is a cross-sectional view of a cryoballoon catheter according to another embodiment of the present application.

[0027] Reference numerals: inner balloon 10 , outer balloon 20 , supporting medium 11 , freezing cavity 21 , inlet 22 , outlet 23 , liquid inlet pipe 12 , refrigerant pipe 24 , sealing element 13 , liquid inlet hole 14 , protective protrusion 25 . DETAILED DESCRIPTION

[0028] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0029] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should have the usual meaning understood by people with ordinary skills in the field to which this application belongs. The words "include" or "comprise" and the like used in this application specification and claims mean that the elements or objects appearing before "include" or "comprise" cover the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0030] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0031] In this application, the distal end refers to the end of a medical device that is away from the operator. In the context of ablation catheter procedures, the distal end is the distal tip of the catheter, typically the end that contacts the patient's internal tissue or organ. The proximal end refers to the end of the ablation catheter that is closest to the operator. In medical procedures, the proximal end is typically the end the operator uses to control the ablation catheter and serves as the starting point for the ablation catheter. The proximal end typically corresponds to the operator and is used to control the catheter's direction and position.

[0032] The present application provides a cryoballoon catheter. The cryoballoon catheter of the present application is described in detail below in conjunction with the accompanying drawings. The features of the following embodiments and implementations may be combined with each other unless they conflict.

[0033] like Figure 1As shown, the present application provides a cryoballoon catheter, comprising an inner balloon 10 and an outer balloon 20, wherein the inner balloon 10 is located inside the outer balloon 20. The inner balloon 10 is used to inject a supporting medium 11, which switches between a solid state and a liquid state. During injection, the supporting medium 11 enters the inner balloon 10 in a liquid state, and the inner balloon 10 can adapt to the diameter of the human body cavity in the radial direction so as not to damage the human body cavity. Subsequently, the state of the supporting medium 11 can be controlled by temperature changes or application of an electric field, thereby changing the compliance of the inner balloon 10. After the supporting medium 11 becomes solid, the outer contour of the inner balloon 10 is a non-compliant balloon close to the outer balloon 20.

[0034] A freezing cavity 21 is formed between the outer balloon 20 and the inner balloon 10, into which the refrigerant is injected. After the supporting medium 11 solidifies, the non-compliant inner balloon 10 squeezes the space in the freezing cavity 21, forcing the refrigerant to adhere to the outer balloon 20 wall as it flows through the freezing cavity 21, achieving a better freezing effect and wider ice ball coverage.

[0035] The freezing cavity 21 includes an inlet 22 and an outlet 23. After the refrigerant enters the freezing cavity 21 from the inlet 22, it is vaporized after heat transfer with the outside and flows out from the outlet 23. There can be one or more outlets 23.

[0036] In some embodiments, the supporting medium 11 within the inner balloon 10 is a high-freezing-point liquid, which becomes solid after heat transfer through the refrigerant. High-freezing-point liquids are economical and convenient to obtain, and can be converted from solid to liquid in conjunction with a refrigerant. High-freezing-point liquids also easily convert to liquid form after rewarming. Once converted to liquid form, the inner balloon 10 can adapt radially to the diameter of the human body's cavity, allowing the cryoballoon catheter to be removed without damaging the cavity. Preferably, the high-freezing-point liquid can be physiological saline, which is harmless to the human body.

[0037] In some embodiments, the device further includes: a liquid inlet tube 12 , which is disposed in the inner balloon 10 and has a liquid inlet hole 14 , through which high freezing point liquid flows to fill the inner balloon 10 .

[0038] In some embodiments, a refrigerant tube 24 is further included. The refrigerant tube 24 is nested within the liquid inlet tube 12 and extends axially from the inner balloon 10 into the freezing cavity 21. The section of the refrigerant tube 24 extending into the freezing cavity 21 includes an inlet 22. The refrigerant tube 24 is used to inject refrigerant into the outer balloon 20, so that the refrigerant fills the freezing cavity 21 between the inner and outer balloons 10 and 20. Therefore, the inlet 22 of the refrigerant tube 24 is used to release refrigerant into the freezing cavity 21. The refrigerant tube 24 is nested within the liquid inlet tube 12 to pre-cool the supporting working medium 11 within the liquid inlet tube 12.

[0039] In some other embodiments, such as Figure 2 As shown, the refrigerant tube 24 is arranged in parallel with the liquid inlet tube 12 , and the refrigerant tube 24 axially passes through the inner balloon 10 into the freezing cavity 21 , and the section of the refrigerant tube 24 extending into the freezing cavity 21 includes the inlet 22 .

[0040] In some embodiments, the inner balloon 10 further includes a seal 13, which is disposed around the refrigerant tube 24. Because the refrigerant tube 24 penetrates the inner balloon 10, ensuring its sealing is difficult. To prevent leakage of the working fluid within the inner and outer balloons 10 and 20, the seal 13 surrounding the refrigerant tube 24 is provided to enhance the sealing of the inner balloon 10. In other embodiments, the portion of the balloon surrounding the refrigerant tube 24 is ultrasonically or thermally welded to the refrigerant tube 24 to enhance sealing.

[0041] In some embodiments, the liquid inlet tube 12 is provided with at least one liquid inlet hole 14, which is evenly distributed along the liquid inlet tube 12. The uniform distribution of the liquid inlet holes 14 in both the radial and axial directions of the liquid inlet tube 12 allows the liquid support medium 11 to flow evenly into the inner balloon 10, preventing the refrigerant flow from causing a rapid drop in temperature within the inner balloon 10 and causing the support medium 11 to form an uneven solid state. The even distribution of the liquid inlet holes 14 ensures a uniform shape of the freezing cavity 21, allowing the refrigerant to flow closely against the wall of the outer balloon 20.

[0042] In some embodiments, the supporting working fluid 11 is an electrorheological fluid, which is connected to an external electric field generator. The electrorheological fluid undergoes liquid and solid conversion under the control of the external electric field generator. Electrorheological fluid is an intelligent material that can undergo a reversible liquid-solid transformation under the action of an electric field. Its rheological properties, such as shear stress, modulus and viscosity, will change significantly before and after the application of the electric field. When no electric field is applied, the electrorheological fluid flows from the liquid inlet tube 12 into the inner balloon 10 in the form of a Newtonian fluid. After the external electric field is applied, the electrorheological fluid becomes solid. The electrorheological fluid has a high degree of controllability and can be quickly converted between solid and liquid states, saving surgical time. In addition, the solid-liquid conversion process is reversible and can be reused.

[0043] Similarly, magnetorheological fluids (MRFs) are fluids whose rheological properties are altered by an external magnetic field, which changes the arrangement and interaction of the magnetic particles within the fluid. The strength and direction of the magnetic field determine changes in the fluid's viscosity and shear yield stress. Under zero magnetic field conditions, MRFs exhibit the properties of a low-viscosity Newtonian fluid with good fluidity. When subjected to an external magnetic field, the magnetic particles within the MRF become magnetized and arranged in a regular pattern, forming particle chains. At this point, the fluid exhibits high viscosity and low fluidity, similar to a solid. The MR effect is reversible; when the external magnetic field is removed, the MRF quickly returns to its original low-viscosity state.

[0044] like Figure 3 As shown, in some embodiments, the tip of the outer balloon 20 has a protective protrusion 25. The tip of the outer balloon 20 is the farthest end of the balloon and directly contacts the refrigerant flowing out of the refrigerant tube 24. Therefore, the protective protrusion 25 is used to reinforce the tip of the balloon to prevent damage due to uneven temperature distribution or excessive pressure.

[0045] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0046] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A cryoballoon catheter comprising: An inner layer balloon and an outer layer balloon, wherein the inner layer balloon is located inside the outer layer balloon, and is characterized in that a supporting medium is provided in the inner layer balloon, and the supporting medium can be converted between solid and liquid states; A freezing cavity is formed between the outer balloon and the inner balloon, and the freezing cavity includes an inlet and an outlet. The refrigerant enters the freezing cavity from the inlet and transfers heat before flowing out from the outlet. The freezing cavity also includes: a liquid inlet pipe and a refrigerant pipe. The liquid inlet pipe is arranged in the inner balloon, and the refrigerant pipe penetrates from the inner balloon into the freezing cavity in the axial direction. After the supporting working medium becomes solid, the inner balloon squeezes the space of the freezing cavity, forcing the refrigerant to stick to the wall of the outer balloon during the flow in the freezing cavity.

2. The cryoballoon catheter according to claim 1, wherein The supporting medium in the inner balloon is a high-freezing-point liquid, which becomes solid after heat transfer by the refrigerant.

3. The cryoballoon catheter according to claim 2, characterized in that The liquid inlet pipe is provided with a liquid inlet hole, and the high freezing point liquid flows into the liquid inlet hole to fill the inner layer balloon.

4. The cryoballoon catheter according to claim 3, characterized in that The refrigerant pipe is nested in the liquid inlet pipe or the refrigerant pipe and the liquid inlet pipe are arranged in parallel, and the section of the refrigerant pipe extending into the freezing cavity includes the inlet.

5. The cryoballoon catheter according to claim 4, characterized in that The inner balloon further includes a sealing member, which is wrapped around the refrigerant tube.

6. The cryoballoon catheter according to claim 4, characterized in that The balloon on the peripheral portion of the refrigerant tube is ultrasonically welded or thermally melted to the refrigerant tube.

7. The cryoballoon catheter according to claim 3, characterized in that The liquid inlet pipe is provided with at least one liquid inlet hole, and the liquid inlet holes are evenly distributed on the liquid inlet pipe.

8. The cryoballoon catheter according to claim 1, characterized in that The supporting working medium is an electrorheological fluid, which is connected to an external electric field generator. The electrorheological fluid performs conversion between liquid and solid under the control of the external electric field generator.

9. The cryoballoon catheter according to claim 1, characterized in that The supporting working medium is a magnetorheological fluid, the magnetorheological fluid is connected to an external magnetic field, and the magnetorheological fluid performs conversion between liquid and solid under the control of the external magnetic field.

10. The cryoballoon catheter according to claim 4, characterized in that The tip of the outer balloon is provided with a protective protrusion.

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