Freezing balloon catheter

Abstract

The invention provides a freezing balloon catheter which comprises an inner-layer balloon and an outer-layer balloon, the inner-layer balloon is located on the inner side of the outer-layer balloon, a supporting working medium is arranged in the inner-layer balloon, and the supporting working medium can be converted between a solid state and a liquid state; a freezing cavity is formed between the outer-layer balloon and the inner-layer balloon, the freezing cavity comprises an inlet and an outlet, and a refrigerant enters the freezing cavity from the inlet, then conducts heat transfer with the outside, is gasified and flows out from the outlet. The phase change of the working medium in the inner-layer balloon is set, the supporting performance of the inner-layer balloon is changed, that is, the solid working medium is used as a supporting basis in the working state, so that the refrigerant for heat transfer is tightly attached to the outer-layer balloon, heat transfer with the focus can be more efficiently conducted, the focus in a large range can be frozen, and the operation time is saved.

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 development of science and technology, the concept of "minimally invasive" has penetrated into all areas of surgical operations. Minimally invasive surgery refers to surgery performed using modern medical devices such as laparoscopes and cystoscopes and related equipment. Compared with traditional surgery, it has significant advantages such as small incisions, less pain, faster recovery, shorter hospital stay, and less bleeding.

[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 treatment 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 action.

[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 balloon wall temperature is close to the balloon center temperature. 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, which can use a solid supporting medium as a supporting basis when working, regardless of the size of the balloon, so that the refrigerant used for freezing is close to the balloon wall, reducing the heat loss of the refrigerant inside the balloon. Most of the existing double-layer balloon designs are designed for safety reasons, with the purpose of preventing high-pressure explosion and balloon damage. CN117695538A discloses a double-layer balloon, with a pressure sensor and a liquid sensor between the inner and outer sub-balloons, which can realize real-time monitoring of the medical balloon, making it convenient for the operator to adjust the surgical process according to whether the balloon is ruptured; other double-layer balloon designs are designed for the purpose of facilitating drug administration, etc., and there is currently no double-layer balloon designed to address the above 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, the cryoballoon catheter can use a solid supporting medium as a supporting basis when working, 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 inside the inner balloon, and the supporting medium can be switched between a solid state and a liquid state;

[0008] A freezing cavity is formed between the outer layer balloon and the inner layer balloon. The freezing cavity includes an inlet and an outlet. After the refrigerant enters the freezing cavity from the inlet and transfers heat 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 penetrates from the inner layer balloon into the freezing cavity in the axial direction, 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 penetrates from the inner layer balloon into the freezing cavity in the axial direction, and the section of the refrigerant tube extending into the freezing cavity includes the inlet.

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

[0013] Optionally, the balloon around the refrigerant tube is ultrasonically welded or heat-melt welded 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 a liquid-solid conversion under the control of the external electric field generator.

[0016] Optionally, the supporting working fluid is a magnetorheological fluid, the magnetorheological fluid is connected to an external magnetic field, and the magnetorheological fluid performs a 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 a support basis, so that the refrigerant used for freezing is close to the wall of the outer balloon. The refrigerant in the outer balloon reduces the heat loss inside the balloon, and can transfer heat to the lesion more efficiently, thereby freezing a large range 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 against the balloon wall to be close to the lesion, thereby achieving more efficient heat transfer. The high freezing point liquid makes the present technical solution more cost-effective and easy to implement.

[0021] 3. In the present application, the liquid inlet tube for conveying high freezing point liquid to the inner balloon and the refrigerant tube for conveying refrigerant to the outer balloon are nested, which simplifies the internal structure of the balloon and saves 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

[0024] 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.

[0025] Figure 1 Shown is a cross-sectional view of a cryoballoon catheter according to one embodiment of the present application.

[0026] Figure 2 Shown is a cross-sectional view of a cryoballoon catheter according to yet another embodiment of the present application.

[0027] Figure 3 Shown is a cross-sectional view of a cryoballoon catheter according to another embodiment of the present application.

[0028] 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

[0029] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0030] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "including" or "comprising" and the like used in this application specification and claims mean that the elements or objects appearing before "including" or "comprising" include the elements or objects listed after "including" or "comprising" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, and may include electrical connections, whether direct or indirect.

[0031] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0032] In this application, the distal end refers to the end of the medical device that is away from the operator. In the medical operation of an ablation catheter, the distal end is the end of the catheter, which is usually the end that contacts the tissue or organ in the patient's body. The proximal end refers to the end of the ablation catheter that is close to the operator. In medical operations, the proximal end is usually the end that the operator uses to control the ablation catheter and is also the starting point of the ablation catheter. The proximal end usually corresponds to the operator and is used to control the direction and position of the catheter.

[0033] 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. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0034] 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 on the inner side of 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 be adaptively changed in the radial direction with the diameter of the human body cavity 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.

[0035] A freezing cavity 21 is formed between the outer balloon 20 and the inner balloon 10, and the freezing cavity 21 is used to inject the refrigerant. After the supporting medium 11 becomes solid, the non-compliant inner balloon 10 squeezes the space of the freezing cavity 21, forcing the refrigerant to adhere to the wall of the outer balloon 20 during the flow of the freezing cavity 21, so as to achieve a better freezing effect and obtain a larger ice ball coverage.

[0036] 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. One or more outlets 23 may be provided.

[0037] In some embodiments, the supporting medium 11 in the inner balloon 10 is a high freezing point liquid, which becomes solid after heat transfer by the refrigerant. The acquisition of high freezing point liquid is economical and convenient, and can be used with the refrigerant to achieve the conversion between solid and liquid. The high freezing point liquid is also easy to convert into liquid after rewarming. After conversion into liquid, the inner balloon 10 can adapt to the diameter of the human body cavity in the radial direction, and the cryoballoon catheter can be removed without damaging the human body cavity. Preferably, the high freezing point liquid can be physiological saline that is harmless to the human body.

[0038] In some embodiments, it also includes: a liquid inlet tube 12, which is arranged in the inner layer balloon 10, and a liquid inlet hole 14 is provided on the liquid inlet tube 12, and a high freezing point liquid flows into the liquid inlet hole 14 to fill the inner layer balloon 10.

[0039] In some embodiments, a refrigerant tube 24 is further included, and the refrigerant tube 24 is nested in the liquid inlet tube 12, and the refrigerant tube 24 axially penetrates from the inner layer balloon 10 to the freezing cavity 21, and 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 layer balloon 20, so that the refrigerant fills the freezing cavity 21 between the inner layer balloon 10 and the outer layer balloon 20, so the inlet 22 of the refrigerant tube 24 is used to release the refrigerant into the freezing cavity 21. The refrigerant tube 24 is nested in the liquid inlet tube 12, and the supporting working medium 11 in the liquid inlet tube 12 can be precooled.

[0040] 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 from the inner balloon 10 to the freezing cavity 21 , and the section of the refrigerant tube 24 extending into the freezing cavity 21 includes the inlet 22 .

[0041] In some embodiments, the inner balloon 10 further includes a seal 13, which is wrapped around the refrigerant tube 24. Since the refrigerant tube 24 is arranged to penetrate, the sealing of the inner balloon 10 is difficult to ensure. In order to prevent leakage of the working fluid in the inner balloon 10 and the outer balloon 20, the sealing of the inner balloon 10 is enhanced by arranging the seal 13 around the refrigerant tube 24. In some other embodiments, the balloon around the refrigerant tube 24 is ultrasonically welded or heat-melted to the refrigerant tube 24 to enhance the sealing.

[0042] In some embodiments, at least one liquid inlet hole 14 is provided on the liquid inlet tube 12, and the liquid inlet holes 14 are evenly distributed on the liquid inlet tube 12. The liquid inlet holes 14 are evenly distributed in the radial direction and the axial direction of the liquid inlet tube 12, so that the liquid support medium 11 flows evenly into the inner layer balloon 10, and prevents the temperature in the inner layer balloon 10 from dropping rapidly due to the flow of the refrigerant, so that the support medium 11 forms an uneven solid state. The even distribution of the liquid inlet holes 14 ensures that the shape of the freezing cavity 21 is uniform, so that the refrigerant flows closely to the wall of the outer layer balloon 20.

[0043] In some embodiments, the supporting medium 11 is an electrorheological fluid, which is connected to an external electric field generator, and the electrorheological fluid converts between liquid and solid 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 an 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 an electric field is applied externally, the electrorheological fluid becomes solid. The electrorheological fluid has a high degree of controllability, and the conversion between solid and liquid is rapid, which saves surgical time, and the solid-liquid conversion process is reversible and can be reused.

[0044] Similarly, magnetorheological fluid is a fluid whose rheological properties are changed by an external magnetic field by changing the arrangement and interaction of magnetic particles in the fluid. The strength and direction of the magnetic field determine the changes in fluid viscosity and shear yield stress. Under zero magnetic field conditions, magnetorheological fluid exhibits low-viscosity Newtonian fluid properties and good fluidity. When subjected to an external magnetic field, the magnetic particles in the magnetorheological fluid are magnetized and arranged regularly to form particle chains. At this time, the fluid exhibits high viscosity and low fluidity, similar to a solid. The magnetorheological effect is reversible. When the external magnetic field is removed, the magnetorheological fluid will quickly return to its original low-viscosity state.

[0045] 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 the farthest end directly contacts the refrigerant flowing out of the refrigerant tube 24. Therefore, the protective protrusion 25 is used to reinforce the tip to prevent the balloon tip from being damaged due to uneven temperature distribution or high pressure.

[0046] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0047] It should be understood that the present application is not limited to the precise structures that have been 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 inside the inner layer balloon, and the supporting medium can be switched between a solid state and a liquid state; A freezing cavity is formed between the outer layer balloon and the inner layer balloon. 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.

2. The cryoballoon catheter according to claim 1, characterized in that: 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.

3. The cryoballoon catheter according to claim 2, characterized in that: Also includes: A liquid inlet tube is arranged in the inner layer balloon, and a liquid inlet hole is provided on the liquid inlet tube, 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: Also includes: A refrigerant tube, wherein the refrigerant tube is nested in the liquid inlet tube and extends axially from the inner balloon to the freezing cavity, and a section of the refrigerant tube extending into the freezing cavity includes the inlet; Alternatively, the refrigerant tube and the liquid inlet tube are arranged in parallel, and the refrigerant tube penetrates from the inner balloon into the freezing cavity in the axial direction, and the section of the refrigerant tube extending into the freezing cavity includes the inlet.

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

6. The cryoballoon catheter according to claim 4, characterized in that: The balloon around 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 a liquid-solid conversion 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 a conversion between a liquid state and a solid state 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 has a protective protrusion.

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