Balloon, balloon catheter, ablation catheter, and tubular ultrasonic focusing apparatus and method

Abstract

The present application provides a balloon, a balloon catheter, an ablation catheter, and a tubular ultrasonic focusing apparatus and method, which relate to the field of medical devices. An expanded state of the balloon comprises a first extension section, a lens section, and a second extension section. The lens section is disposed between the first extension section and the second extension section in an axial direction. The lens section comprises a converging structure made of an energy-permeable material, wherein the converging structure is configured to converge energy from the lens section to a target converging region. The balloon catheter comprises a balloon, an energy generator, a first axial fixing member, and a second axial fixing member. The energy generator is disposed in a hollow channel of the lens section, and the energy generator has a length corresponding to the lens section in an axial direction. When the balloon catheter provided in embodiments of the present application is applied to an ablation surgery, accurate focusing on a target ablation region can be achieved based on the lens section, and damage to surrounding tissues can be minimized while precisely targeting nerves in the target ablation region, thereby improving the effect of the ablation surgery. In addition, by means of a focusing / weak focusing region formed by an acoustic beam adjustment structure, the ablation depth and precision can be adjusted, and synchronous temperature rise in the target region is achieved. The balloon catheter has the advantages of uniform and consistent ablation effect and obvious distal boundary, and can achieve the precise ablation of renal artery branches and trunks, which ensures the thoroughness of ablation, reduces damage to surrounding normal tissues to the greatest extent, meets the clinical requirements of "ablation to completion", and improves the effectiveness and safety of treatment.

Description

Balloon, balloon catheter, ablation catheter, and tubular ultrasound focusing device and method Cross-reference to Related Applications

[0001] This application claims priority to (1) Chinese Patent Application No. 202411267299.7, filed September 11, 2024, entitled “A Tubular Ultrasound Focusing Device and Method,” and (2) Chinese Patent Application No. 202510722105.6, filed May 30, 2025, entitled “Balloon, Balloon Catheter, and Ablation Catheter,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of medical devices and ultrasound ablation, and in particular, to a balloon, a balloon catheter, and an ablation catheter, and a tubular ultrasound focusing / weak focusing device and method. BACKGROUND

[0003] Ablation is a medical technology that destroys or removes body tissue through physical or chemical means. Common ablation methods include radiofrequency ablation, which heats and destroys target tissue through high-frequency electric current; laser ablation, which destroys diseased tissue using laser energy; cryoablation, which freezes and kills diseased tissue through extremely low temperatures (usually using liquid nitrogen or other coolants); and chemical ablation, which dissolves or destroys diseased tissue through the injection of chemical drugs.

[0004] Energy is concentrated on target tissue, and specific nerve fibers or ganglions of the target tissue are destroyed to interrupt the transmission of pathological nerve signals, thereby treating diseases caused by excessive activity of sympathetic nerves, abnormal pain transmission, or autonomic nervous dysfunction (such as hypertension, arrhythmia, chronic pain, etc.). Common ablation procedures targeting nerves include pulmonary artery denervation (PADN), renal artery sympathetic denervation (RDN), and endovascular sympathetic denervation (EDN). In addition, there are various other nerve ablation techniques, mainly targeting excessively active or pathological nerve pathways, for the treatment of refractory hypertension, arrhythmia, and pain syndromes.

[0005] During the above-mentioned nerve ablation procedures, it is often necessary to rely on ablation catheters to perform interventional procedures. Common ablation catheters are provided with ablation energy release elements on the catheter stent, and different target positions are ablated by designing the arrangement of the ablation energy release elements.

[0006] In November 2023, ReCor's Paradise RDN system based on ultrasound ablation technology and Medtronic's Symplicity Spyral RDN system based on radiofrequency ablation technology became the first two products approved by the US FDA for the treatment of primary hypertension.

[0007] In the Symplicity Spyral radiofrequency RDN system, the energy device is four ring-shaped metal electrodes placed on a coiled memory metal guide wire, the ablation mechanism is that the electrodes contact the blood vessel wall and apply a 448Khz radiofrequency current to the blood vessel wall, the current flows through the area and the tissue generates heat, the ablation depth is less than 4mm adjacent to each electrode, and the ablation temperature can reach more than 600, the ablation range is that each ablation point is not in the same axial plane and only covers one quadrant in the projection direction, and the blood vessel protection is only relying on arterial blood cooling without a dedicated cooling mechanism.

[0008] In May 2024, the National Medical Products Administration of China approved Medtronic's Symplicity Spyral RDN system for the treatment of refractory hypertension on the Chinese market, becoming the first RDN product approved on the Chinese market.

[0009] In the Paradise ultrasound RDN system, the energy device is a tubular piezoelectric ceramic tube placed in a balloon that can pass through a cold cutting liquid, the ablation mechanism is that the balloon wall contacts the blood vessel and the tubular transducer radially emits 10Mhz ultrasound energy, the mechanical wave vibration causes the tissue to heat up, the ablation depth is axisymmetric with an axial length of 6mm and a radial outer diameter of up to 8mm, the ablation range is similar to a "swimming ring" 360-degree ring, and the blood vessel protection is that the balloon passes through a cooling liquid to ensure that the blood and the blood vessel wall are less than 42° in thickness, the conventional tubular transducer sound field intensity used by this product is not uniformly distributed radially, and generally decays by the negative first power with the radius. This will cause the target ablation area to be easily over-ablated in the near area, and the ablation is insufficient in the far area. At the same time, part of the sound field penetrates to the non-target area farther away, causing the tissue in this area to have a certain risk of damage.

[0010] Existing ablation devices and methods show that the production process of the ablation energy release element is difficult and the development cycle is long, and the energy gathering effect needs to be improved. SUMMARY

[0011] The purpose of the embodiments of the present application is to provide a balloon, a balloon catheter and an ablation catheter, which accurately focus on the target ablation area through the lens segment, can accurately target the nerves in the target ablation area while minimizing damage to the surrounding tissue, and improve the effect of ablation surgery.

[0012] In a first aspect, the embodiments of the present application provide a balloon, the expanded state of the balloon comprising: a first extended section, a lens section and a second extended section; the lens section is arranged between the first extended section and the second extended section along an axial direction; the lens section comprises a converging structure made of an energy-permeable material; wherein the converging structure is configured to converge energy from a hollow channel in the lens section to a target converging area.

[0013] In the implementation process described above, the balloon provided by the embodiments of the present application comprises a first extended section, a lens section and a second extended section, wherein the lens section comprises a converging structure capable of converging energy from a hollow channel in the lens section to a target converging area. By designing the converging structure, energy can be converged to different depths, i.e., the focus is adjusted. By using the balloon structure provided by the embodiments of the present application in the catheter for interventional surgery and cooperating with an energy generator, precise ablation of the target ablation point can be achieved; not only the precise convergence of energy can be achieved, but also the temperature rise speed of the ablation point can be improved, the duration of the ablation surgery can be shortened, and the patient's surgical experience can be improved.

[0014] Optionally, in the embodiments of the present application, the converging structure comprises a plurality of first thickness sections and a plurality of second thickness sections; the radial dimensions of the first thickness sections and the second thickness sections are different; the plurality of first thickness sections and the plurality of second thickness sections are arranged in an axial direction.

[0015] In the implementation process described above, the converging structure of the balloon provided by the embodiments of the present application comprises first thickness sections and second thickness sections with different sizes in the radial direction, and the first thickness sections and the second thickness sections are arranged in an axial direction. The embodiments of the present application provide a balloon by giving the lens section the acoustic characteristics of a Bessel lens or a Fresnel lens to realize the regulation of the energy distribution from the hollow channel of the balloon; wherein for the Bessel balloon, the lengths of the first thickness sections and the second thickness sections in the axial direction are consistent, and by adjusting the number of the first thickness sections and the second thickness sections, the control of the energy distribution from the hollow channel of the balloon can be realized.

[0016] Optionally, in the embodiments of the present application, the lens section comprises an intermediate length section; the intermediate length section is arranged at the axial middle part of the lens section, and the converging structure is arranged on both sides of the intermediate length section.

[0017] In the implementation process, the balloon provided by the embodiment of the application includes a Fresnel balloon and a quasi-Bessel balloon. The Fresnel balloon can be designed in the axial direction according to the Fresnel zone plate formula and the position of energy convergence that needs to be controlled. The quasi-Bessel lens is a simplified structure of the Bessel lens, and the length of the middle part is flexibly controlled to accurately control the position of energy convergence. Therefore, the balloon provided by the embodiment of the application can be endowed with the acoustic structural characteristics of the Bessel lens, the Fresnel lens and the quasi-Bessel lens. Flexible adjustment of the structural parameters can control the energy to converge in the target area, and the balloon can be applied to the catheter setting in the ablation operation, and can be used in cooperation with the energy generator to help accurate ablation of the target ablation position.

[0018] Optionally, in the embodiment of the application, the balloon is a non-compliant balloon.

[0019] In the implementation process, in the ablation operation, the non-compliant balloon can ensure that the ablation energy is uniformly transmitted to the target tissue through the closely fitted balloon wall, so as to avoid uneven energy distribution or tissue damage caused by excessive expansion of the balloon. In addition, the high burst pressure can safely withstand the high pressure environment required by the operation, and stably support the integrated electrode or transducer, accurately position the ablation target point, thereby improving the safety and effectiveness of the ablation operation.

[0020] In a second aspect, the embodiment of the application provides a balloon catheter, which includes a balloon, an energy generator, a first axial fixing member and a second axial fixing member. The expanded state of the balloon includes a first extended section, a lens section and a second extended section. The lens section is arranged between the first extended section and the second extended section along the axial direction. The energy generator is arranged in the hollow channel of the lens section, and the energy generator has a length corresponding to the lens section in the axial direction. The first axial fixing member is arranged in the hollow channel of the first extended section and is fixedly connected with the first end of the energy generator. The second axial fixing member is arranged in the hollow channel of the second extended section and is fixedly connected with the second end of the energy generator. The converging structure of the lens section is configured to converge the energy generated by the energy generator in the target converging area.

[0021] In the implementation process, the balloon catheter provided in the embodiment of the present application can realize precise ablation of a target ablation point, and can not only realize precise energy convergence, but also improve the temperature rise speed of the ablation point, shorten the duration of the ablation surgery, and improve the patient's surgical experience.

[0022] Optionally, in the embodiment of the present application, the converging structure includes a first thickness section with a thickness of a basic thickness d1 and a second thickness section with a thickness of d2; the thickness d2 of the second thickness section is the basic thickness d1 plus a phase difference thickness d; the phase difference thickness d is determined based on a phase difference between adjacent wave groups generated by the energy generator.

[0023] In the implementation process, the converging structure of the balloon in the balloon catheter provided in the embodiment of the present application is designed with a binary distribution thickness, which can give the lens section the acoustic characteristics of a Bessel or Fresnel lens, and by adjusting the number of the first thickness section and the second thickness section, the distribution of energy (such as energy emitted by an ultrasonic transducer) from the hollow channel of the balloon can be controlled. In the denervation ablation surgery, the balloon catheter provided in the embodiment of the present application can precisely focus energy on a target ablation area, effectively reduce the duration of the ablation surgery, and improve the patient's comfort during the surgery.

[0024] Optionally, in the embodiment of the present application, the length of the first thickness section and the second thickness section in the axial direction is approximately equal to or equal to the phase difference thickness d.

[0025] In the implementation process, in the Bessel balloon catheter and quasi-Bessel balloon catheter provided in the embodiment of the present application, the length of each first thickness section and second thickness section in the axial direction is set to be approximately equal to or equal to the phase difference thickness d, which can realize precise notification of linear phase delay and generate a non-diffractive Bessel beam.

[0026] Optionally, in the embodiment of the present application, the converging feature of the converging structure is consistent with the converging feature of a quasi-Bessel lens; and the middle length section of the lens section is determined based on the position of the target converging area.

[0027] In the implementation process, the converging structure of the quasi-Bessel balloon catheter provided in the embodiment of the present application has the same converging feature as the quasi-Bessel lens. In the embodiment of the present application, the adjustment of the first thickness section and the second thickness section in the middle part of the Bessel balloon catheter is performed by taking the RDN surgery as an example. It can be verified through simulation that the quasi-Bessel balloon catheter provided in the embodiment of the present application can realize the energy convergence of the target ablation area required by the RDN surgery, and the structure is simple and has strong manufacturability, thereby providing strong and reliable support for the ablation surgery.

[0028] Optionally, in the embodiment of the present application, the converging structure has the same converging feature as the Bessel lens; the number of the first thickness section and the second thickness section is n and n+1 respectively; and n is determined based on the position of the target converging area.

[0029] In the implementation process, the Bessel balloon catheter provided in the embodiment of the present application has the lens section of the whole balloon covered with the converging structure, the first thickness section and the second thickness section are staggered distributed in the converging structure, and the length of the first thickness section and the second thickness section in the axial direction is consistent. The distribution of the energy from the hollow channel of the balloon can be adjusted by designing the number of the first thickness section and the second thickness section.

[0030] Optionally, in the embodiment of the present application, the converging structure includes n first thickness sections and n+1 second thickness sections; in the case that the distance between the center point of the target converging area position and the outer surface of the lens section in the radial direction is between 5.7mm and 6.3mm, n is 11.

[0031] In the implementation process, the balloon catheter provided in the embodiment of the present application includes the Bessel balloon catheter, and the converging structure has the same converging feature as the Bessel lens. In the embodiment of the present application, the parameter design and adjustment are performed by taking the RDN surgery as an example. It can be verified through simulation that the Bessel balloon catheter provided in the embodiment of the present application can realize the energy convergence of the target ablation area required by the RDN surgery.

[0032] Optionally, in the embodiment of the present application, the converging structure has the same converging feature as the Fresnel lens; the length of the first thickness section, the second thickness section and the intermediate length section in the axial direction is determined based on the position of the target converging area according to the Fresnel zone plate formula.

[0033] In the implementation process, the converging structure of the Fresnel balloon catheter provided in the embodiment of the present application is consistent with the converging feature of the Fresnel lens. The embodiment of the present application takes the RDN surgery as an example to calculate the length of the first thickness section and the second thickness section in the middle part of the Fresnel balloon catheter. Through simulation, it can be verified that the Fresnel balloon catheter provided in the embodiment of the present application can realize energy convergence on the target ablation area required by the RDN surgery, and the structure is simple, highly manufacturable, and can significantly shorten the duration of the ablation surgery, providing strong and reliable support for the ablation surgery.

[0034] Optionally, in the embodiment of the present application, the position of the target converging area is determined according to the target physiological position to be ablated.

[0035] Optionally, in the embodiment of the present application, the target physiological position includes the sympathetic nerve position or parasympathetic nerve position of the renal artery, duodenum, celiac artery, abdominal aorta, common hepatic artery and proper hepatic artery.

[0036] In the implementation process, the position of the target converging area of the balloon catheter provided in the embodiment of the present application is determined according to the target physiological position to be ablated. Based on the determination of the converging position of the energy based on the physiological position, precise ablation is realized, and the safety and effectiveness of the treatment are significantly improved. Both the target tissue can be destroyed, and the surrounding healthy structure can be protected to the maximum extent; the balloon catheter provided in the embodiment of the present application can significantly improve the ablation surgery precision, efficiency and safety of complex diseases such as metabolic syndrome and intractable visceral pain, and promote the development of minimally invasive surgery to high precision.

[0037] In a third aspect, the embodiment of the present application provides an ablation catheter, which includes an energy generator, a first axial fixing member, a second axial fixing member, and a balloon having a first extension section, a lens section and a second extension section in an expanded state; the lens section is arranged between the first extension section and the second extension section, the radial dimensions of the first extension section and the second extension section increase in the direction of the lens section in the axial direction, and the first extension section and the second extension section are connected with the lens section; the energy generator is arranged in the hollow channel of the lens section; the first axial fixing member is arranged in the hollow channel of the first extension section and fixedly connected with the first end of the energy generator; the second axial fixing member is arranged in the hollow channel of the second extension section and fixedly connected with the second end of the energy generator; the length of the energy generator in the axial direction of the lens section is equal; wherein the converging structure of the lens section is configured to converge the energy generated by the energy generator to a target converging area.

[0038] In a fourth aspect, the present application provides a tubular ultrasound focusing / weak focusing device, comprising a balloon, a transducer arranged in the balloon, the transducer emitting an acoustic beam for ablation, and an acoustic beam adjusting structure distributed axially along the balloon; the acoustic beam passing through the balloon and the acoustic beam adjusting structure forms an adjustable focusing / weak focusing area outside the balloon.

[0039] Optionally, the acoustic beam adjusting structure is formed by the lens segment in the first aspect or the embodiments of the present application, so that the acoustic beam passing through the converging structure made of energy-permeable material in the lens segment is modulated to form a modulated converging area or an adjustable focusing / weak focusing area.

[0040] Optionally, the acoustic beam adjusting structure comprises at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are arranged on the balloon wall.

[0041] Optionally, the acoustic beam adjusting structure comprises at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are arranged on the outer wall of the transducer.

[0042] Optionally, the acoustic beam adjusting structure comprises at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are arranged in the region between the transducer and the balloon.

[0043] Optionally, the acoustic unit structures are arranged in at least multiple groups in axial symmetry along the balloon, and the at least multiple groups of acoustic unit structures are arranged at both ends of the balloon.

[0044] Optionally, the acoustic unit structures comprise a first medium and a second medium, and the first medium and the second medium are arranged in a spaced manner.

[0045] Optionally, the first medium and the second medium are adjacent in size.

[0046] Optionally, the first medium is annular and arranged on the outer wall of the balloon in axial symmetry.

[0047] Optionally, the first medium is the same as the balloon material.

[0048] In a fifth aspect, the present application provides a tubular ultrasound focusing / weak focusing method, which uses the above-mentioned tubular ultrasound focusing / weak focusing device to ablate the target area.

[0049] In the fourth and fifth aspects of the present application, the ablation depth and precision and the synchronous temperature rise in the target region can be adjusted by adjusting the ultrasonic frequency, the distance between the acoustic structure and the incident surface of the treatment region, and the focused / weakly focused region formed by the acoustic beam adjusting structure. Moreover, the tubular ultrasonic focusing / weak focusing device and the tubular ultrasonic focusing / weak focusing method provided by the present application have the advantages of uniform and consistent ablation effect and obvious distal boundary, can realize precise ablation of the renal artery branches and the main stem, ensure the thoroughness of ablation, and minimize the damage to the surrounding normal tissues, meet the clinical requirement of "ablation as much as possible", and improve the effectiveness and safety of treatment.

[0050] Other features and advantages of the present application will be set forth in the following description. The objectives and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims hereof. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application, as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0052] FIG. 1 is a structural schematic diagram of a traditional balloon;

[0053] FIG. 2 is a structural schematic diagram of a Bessel balloon provided by the embodiments of the present application;

[0054] FIG. 3 is a structural schematic diagram of a Fresnel balloon provided by the embodiments of the present application;

[0055] FIG. 4 is a structural schematic diagram of a quasi-Bessel balloon provided by the embodiments of the present application;

[0056] FIG. 5 is a structural schematic diagram of a traditional balloon catheter;

[0057] FIG. 6 is an acoustic simulation result diagram of a traditional balloon catheter provided by the embodiments of the present application;

[0058] FIG. 7 is a structural schematic diagram of a Bessel balloon catheter provided by the embodiments of the present application;

[0059] FIG. 8 is a structural schematic diagram of a Fresnel balloon catheter provided by the embodiments of the present application;

[0060] FIG. 9 is a structural schematic diagram of a quasi-Bessel balloon catheter provided by the embodiments of the present application;

[0061] Fig. 10 is an acoustic simulation result diagram of a Bessel balloon catheter provided by an embodiment of the present application;

[0062] Fig. 11 is an acoustic simulation result diagram of a quasi-Bessel balloon catheter provided by an embodiment of the present application;

[0063] Fig. 12 is an acoustic simulation result diagram of a Fresnel balloon catheter provided by an embodiment of the present application;

[0064] Fig. 13 is a bio-heat simulation result diagram of a conventional balloon catheter provided by an embodiment of the present application;

[0065] Fig. 14 is a bio-heat simulation result diagram of a Bessel balloon catheter provided by an embodiment of the present application;

[0066] Fig. 15 is a bio-heat simulation result diagram of a quasi-Bessel balloon catheter provided by an embodiment of the present application;

[0067] Fig. 16 is a bio-heat simulation result diagram of a Fresnel balloon catheter provided by an embodiment of the present application;

[0068] Fig. 17 is a radial position temperature change curve diagram of a 6mm provided by an embodiment of the present application;

[0069] Fig. 18 is a temperature distribution diagram of a transducer axial center position after 14 seconds provided by an embodiment of the present application;

[0070] Fig. 19 is a transducer radial sound field distribution comparison diagram provided by an embodiment of the present application;

[0071] Fig. 20 is a 6mm sound pressure amplification diagram provided by an embodiment of the present application;

[0072] Fig. 21 is a structure diagram of a tubular ultrasonic weak focusing device provided by an embodiment of the present application;

[0073] Fig. 22 is a structure diagram of a sound beam adjusting structure in a tubular ultrasonic weak focusing device provided by an embodiment of the present application;

[0074] Fig. 23 is a diagram of a treatment state of a sound beam adjusting structure in a tubular ultrasonic weak focusing device provided by an embodiment of the present application;

[0075] Fig. 24 is a structure diagram of a balloon in a tubular ultrasonic weak focusing device provided by an embodiment of the present application;

[0076] Fig. 25 is a diagram of a sound field comparison in a tubular ultrasonic weak focusing device provided by an embodiment of the present application;

[0077] Fig. 26 is a diagram of a temperature field comparison in a tubular ultrasonic weak focusing device provided by an embodiment of the present application;

[0078] Fig. 27 is a schematic diagram of temperature rise comparison in the tubular ultrasonic weak focusing device according to an embodiment of the present application;

[0079] Fig. 28 is a schematic diagram of ablation depth comparison in the tubular ultrasonic weak focusing device according to an embodiment of the present application;

[0080] Fig. 29 is a schematic diagram of temperature rise at different radial points in the tubular ultrasonic weak focusing device according to an embodiment of the present application.

[0081] Fig. 1 is a schematic diagram of a balloon; 101, free propagation zone; 102, first coherence zone; 103, second coherence zone; 2, transducer; 3, inner tube; 4, first acoustic unit structure; 41, first medium; 42, second medium; 5, second acoustic unit structure. Axial direction-Y; radial direction-R; balloon-100; first extension section-110; lens section-120; converging structure-121; first thickness section-1211; second thickness section-1212; intermediate length section-122; second extension section-130; balloon catheter-1000; energy generator-200; first axial fixing member-300; second axial fixing member-400. DETAILED DESCRIPTION

[0082] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0083] Therefore, the following detailed description of the embodiments of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed embodiments of the present application, but only represents selected embodiments of the embodiments of the present application. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the embodiments of the present application.

[0084] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0085] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the embodiments of the present application is usually placed, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0086] In addition, the terms "horizontal", "vertical" and the like do not mean that the components must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0087] In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0088] Ablation is a medical technology that destroys or removes body tissue by physical or chemical means. Among them, the physical means is to concentrate energy on the target tissue, and destroy the specific nerve fibers or nerve ganglions of the target tissue, so as to interrupt the transmission of pathological nerve signals, so as to treat diseases caused by excessive activity of sympathetic nerves, abnormal pain transmission or autonomic nervous dysfunction (such as hypertension, arrhythmia, chronic pain, etc.). Common ablation procedures for nerves include pulmonary artery denervation (PADN), renal artery sympathetic nerve ablation (RDN) and endovascular sympathetic nerve ablation (EDN). In addition, there are many other nerve ablation technologies, mainly aiming at overactive or pathological nerve pathways, for treating refractory hypertension, arrhythmia, pain syndrome and other diseases.

[0089] At present, the common ablation catheter is to arrange an ablation energy releasing element on the catheter support, and to realize ablation on different target positions by designing the arrangement mode of the ablation energy releasing element.

[0090] The inventors have found that in this process, the production process of the ablation energy release element is difficult, the development cycle is long, and the energy convergence effect needs to be improved.

[0091] Based on this, the application provides a balloon, a balloon catheter and an ablation catheter. The balloon includes a first extension section, a lens section and a second extension section, wherein the lens section includes a convergence structure made of an energy-permeable material, and the convergence structure is configured to converge energy from the hollow channel in the lens section to a target convergence area. Further, an energy generator is arranged in the hollow channel of the lens section to form the balloon catheter provided by the application, which has a significant focusing effect, can quickly reach the ablation temperature, shorten the ablation operation time and improve the comfort of patients.

[0092] Taking pulmonary artery denervation (PADN), renal artery denervation (RDN) and endovascular denervation (EDN) as examples, the catheter provided by the application can be applied to the nerve ablation operation of the biological body through the lumen.

[0093] Renal artery denervation (RDN) is a minimally invasive treatment method for controlling refractory hypertension by destroying the sympathetic nerves around the renal artery through radiofrequency ablation, ultrasonic wave or microwave technology, so as to effectively control the overactive sympathetic nerve activity.

[0094] Endovascular denervation (EDN) is a new type of minimally invasive operation for improving the blood glucose control of patients with type 2 diabetes by ablation of the surrounding sympathetic nerves of the renal artery, duodenum, abdominal aorta, abdominal aorta, common hepatic artery and proper hepatic artery.

[0095] Pulmonary hypertension (PH) is a clinical and pathophysiological syndrome caused by structural or functional changes in pulmonary blood vessels due to multiple heterogeneous diseases (etiology) and different pathogenesis, which leads to increased pulmonary vascular resistance and pulmonary arterial pressure, and then develops into right heart failure and even death. The main pathologies of pulmonary hypertension leading to increased pulmonary arterial pressure include pulmonary arterial hypertension, left heart disease, pulmonary disease, pulmonary artery obstruction, unknown factors or multiple factor mechanisms. Pulmonary artery denervation (PADN) is a percutaneous pulmonary artery interventional treatment technology, which uses a specific catheter to deliver radiofrequency energy to the sympathetic nerves of the pulmonary artery adventitia, so that the nerve myelin sheath disappears and the axon fuses, thereby inhibiting the activity of the sympathetic nerves, increasing the cardiac output, reducing the pulmonary arterial pressure and inhibiting the pathological remodeling of the pulmonary artery, and improving the exercise tolerance and cardiac function of the patient.

[0096] In addition, the catheter provided by the embodiment of the present application can be applied to the ablation operation of the biological body through the lumen, can destroy the specific nerve fibers or ganglions of the target tissue, and interrupt the transition conduction of pathological nerve signals, so as to treat the diseases caused by the overactive sympathetic nerves, abnormal pain transmission or autonomic nervous dysfunction.

[0097] Please refer to FIG. 1 to FIG. 4, FIG. 1 is a structural schematic diagram of a conventional balloon; FIG. 2 is a structural schematic diagram of a Bessel balloon provided by the embodiment of the present application; FIG. 3 is a structural schematic diagram of a Fresnel balloon provided by the embodiment of the present application; and FIG. 4 is a structural schematic diagram of a quasi-Bessel balloon provided by the embodiment of the present application. It should be noted that FIG. 1 to FIG. 4 are all in the expanded state of the balloon.

[0098] The balloon 100 is an inflatable / deflatable hollow device made of flexible material, which is expanded by injecting liquid or gas and has a wide range of medical applications. Common materials of the balloon 100 include at least one of polyethylene (PE), polyethylene terephthalate (PET), polyamide (PA) and Pebax.

[0099] Please refer to FIG. 1, which is an example of a conventional balloon. The balloon in FIG. 1 is a conical balloon, i.e., the radial size of both ends is larger than the radial size of the middle part. Commonly, there are cylindrical balloons, spherical balloons, etc. The middle part of the balloon is generally the working section, and the balloon provided by the embodiment of the present application is designed as a lens in the working section, which gives the balloon special lens structure characteristics and realizes the control of energy. It should be understood that the shape of the balloon (e.g., conical, spherical, cylindrical, etc.) should not limit the protection scope of the balloon provided by the embodiment of the present application.

[0100] Please refer to FIG. 2 to FIG. 4, the present application provides a balloon 100, which in the expanded state includes a first extended section 110, a lens section 120 and a second extended section 130. It should be noted that the first extended section 110 and the second extended section 130 are both ends of the balloon 100. In the application scenario of medical devices, the first extended section 110 and the second extended section 130 correspond to the distal end (the end of the medical device close to the operator) and the proximal end (the end of the medical device far from the operator). The lens section 120 is a part with a lens configuration, which is generally arranged in the working section of the balloon 100. It should be noted that the lens section 120 of the balloon 100 provided by the embodiment of the present application is a balloon 100 structure with a lens configuration, not a lens arranged on the balloon 100.

[0101] As shown in FIGS. 2-4, the lens segment 120 is disposed between the first extension segment 110 and the second extension segment 130 in the axial direction (Y). The first extension segment is connected to the lens segment 120 at one end adjacent to the lens segment 120, and the second extension segment 130 is connected to the lens segment 120 at one end adjacent to the lens segment 120, forming the balloon 100.

[0102] The lens segment 120 includes a converging structure 121 made of an energy- permeable material. The converging structure 121 is configured to converge energy from the hollow channel of the lens segment 120 to a target converging region.

[0103] In the above implementation process, the material of the converging structure 121 of the lens segment 120 is an energy-permeable material, which can be selected from common balloon 100 materials such as polyethylene (PE), polyethylene terephthalate (PET), polyamide (PA), and Pebax.

[0104] As can be seen from FIGS. 1-4, the balloon 100 provided in the embodiments of the present application includes a first extension segment 110, a lens segment 120, and a second extension segment 130, wherein the lens segment 120 includes a converging structure 121 that can converge energy from the hollow channel of the lens segment 120 to a target converging region. Through the design of the converging structure 121, energy can be converged to different depths, i.e., the focal point can be adjusted. The structure of the balloon 100 provided in the embodiments of the present application is used in a catheter for interventional surgery, and is used in cooperation with an energy generator 200, which can achieve precise ablation of a target ablation point. Not only can the energy be precisely converged, but the temperature rise speed of the ablation point can also be improved, the duration of the ablation surgery can be shortened, and the patient's surgical experience can be improved.

[0105] Please continue to refer to FIGS. 2-4. In an optional implementation of the embodiments of the present application, the converging structure 121 includes a plurality of first thickness segments 1211 and a plurality of second thickness segments 1212.

[0106] The radial dimensions of the first thickness segments 1211 and the second thickness segments 1212 are different. As shown in FIGS. 2-4, the plurality of first thickness segments 1211 and the plurality of second thickness segments 1212 are arranged in the axial direction (Y) in a staggered manner.

[0107] In the implementation process, the first thickness section 1211 and the second thickness section 1212 have different sizes in the radial direction (R), and the first thickness section 1211 and the second thickness section 1212 are staggered in the axial direction (Y), so that the balloon 100 provided by the embodiment of the application has a binary thickness period function distribution in the axial direction (Y). For example, the arrangement mode in the axial direction (Y) is first thickness section 1211-second thickness section 1212-first thickness section 1211-second thickness section 1212…first thickness section 1211-second thickness section 1212-first thickness section 1211, or second thickness section 1212-first thickness section 1211-second thickness section 1212…first thickness section 1211-second thickness section 1212 arrangement mode.

[0108] Based on the above-mentioned binary distribution thickness design, the lens section 120 can be endowed with the acoustic characteristics of the Bessel lens or the Fresnel lens, so as to realize the regulation of the energy distribution in the hollow channel of the balloon 100.

[0109] The Fresnel lens is a light and thin optical element that realizes light focusing or divergence through a concentric ring structure. It discretizes the continuous curved surface of a traditional lens into a stepped ring, uses the principles of diffraction and refraction to maintain optical performance while reducing thickness, and has the characteristics of light weight but has dispersion and efficiency loss.

[0110] The binary distribution of Fresnel is a diffractive optical design that simulates the refraction effect of a traditional lens by discretizing a concentric ring. Its core is to use the abrupt structure of the ring edge to produce an optical path difference, approximately realize a quadratic phase profile, and thus realize the focusing function in a light and thin plane structure, which can effectively concentrate the energy beam without complex geometric design.

[0111] The Bessel lens is a special optical element that can produce non-diffractive Bessel beams. Bessel beams are known for their non-diffraction characteristics, can produce local sound waves, form standing wave patterns, and are also called "frozen waves". The Bessel lens constructs a conical wavefront to make the light beam maintain a narrow diameter and long focal depth during propagation, overcoming the diffraction and dispersion problem of traditional Gaussian beams.

[0112] The binary distribution of Bessel is to generate an approximate conical phase through a discretized ring structure to produce non-diffractive Bessel beams. This design modulates the wavefront through a ring-shaped diffraction to form a long-focus beam in the axial direction.

[0113] As shown in FIG. 2, FIG. 2 is a structural schematic diagram of the Bessel balloon provided in the embodiments of the present application, in which the whole lens segment 120 of the balloon 100 is covered with the converging structure 121, in which the first thickness segment 1211 and the second thickness segment 1212 are staggered, and the lengths of the first thickness segment 1211 and the second thickness segment 1212 in the axial direction (Y) are consistent. The distribution of the energy from the hollow channel of the balloon 100 can be adjusted by designing the number of the first thickness segment 1211 and the second thickness segment 1212.

[0114] Therefore, the converging structure 121 of the balloon 100 provided in the embodiments of the present application includes the first thickness segment 1211 and the second thickness segment 1212 with different sizes in the radial direction (R), which are staggered in the axial direction (Y) to form the binary thickness distribution of the balloon 100. The balloon 100 provided in the embodiments of the present application can realize the regulation of the energy distribution from the hollow channel of the balloon 100 by giving the lens segment 120 the acoustic characteristics of the Bessel or Fresnel lens. For the Bessel balloon 100, the lengths of the first thickness segment 1211 and the second thickness segment 1212 in the axial direction (Y) are consistent, and the number of the first thickness segment 1211 and the second thickness segment 1212 can be adjusted to control the energy distribution from the hollow channel of the balloon 100.

[0115] Please continue to refer to FIG. 3 and FIG. 4, in the alternative embodiments of the present application, the lens segment 120 further includes the intermediate length segment 122.

[0116] As shown in FIG. 3 and FIG. 4, the intermediate length segment 122 is arranged at the axial middle part of the lens segment 120, and the converging structure 121 is arranged on both sides of the intermediate length segment 122.

[0117] FIG. 3 shows a structural schematic diagram of the Fresnel balloon 100, in which the converging structure 121, i.e., the staggered arrangement of the first thickness segment 1211 and the second thickness segment 1212, is symmetrically arranged on both sides of the intermediate length segment 122. In the Fresnel balloon 100 shown in FIG. 3, the lengths of the first thickness segment 1211 and the second thickness segment 1212 in the axial direction (Y) are determined according to the Fresnel zone plate formula based on the position of the target converging area for which the energy convergence needs to be controlled.

[0118] Figure 4 shows a schematic diagram of a quasi-Bessel balloon 100. It is to be noted that a quasi-Bessel lens is a specially designed optical element that can approximately generate the key characteristics of a Bessel beam (such as non-diffraction, self-repairing, and long focal depth), while overcoming the complexity and energy loss problems of traditional Bessel beam generation methods through simplified structure. In the quasi-Bessel balloon 100 shown in Figure 4, the first thickness section 1211 and the second thickness section 1212 in the focusing structure of the lens section 120 in Figure 2 are removed, and the intermediate length section 122 is generated after the removal. The lengths of the first thickness section 1211 and the second thickness section 1212 on the axial direction (Y) are consistent, and the number and size of the first thickness section 1211 and the second thickness section 1212 on both sides can be designed to control the energy distribution in the hollow channel of the balloon 100.

[0119] As can be seen from Figures 3 and 4, the balloon 100 provided by the embodiments of the present application includes a Fresnel balloon 100 and a quasi-Bessel balloon 100. The Fresnel balloon 100 can be designed according to the Fresnel zone plate formula and the position where the energy convergence needs to be controlled. The quasi-Bessel lens is a simplified structure of the Bessel lens, and the length of the intermediate part is flexibly controlled to accurately control the energy convergence position. Therefore, the balloon 100 provided by the embodiments of the present application can be endowed with the acoustic structural characteristics of the Bessel lens, the Fresnel lens, and the quasi-Bessel lens. The flexible adjustment of the structural parameters can control the energy to converge in the target area, and the balloon 100 can be applied to the catheter setting in the ablation surgery, and can be used in cooperation with the energy generator to help accurately ablate the target ablation position.

[0120] The balloon 100 provided by the embodiments of the present application is a non-compliant balloon (NC). The non-compliant balloon is generally made of high-strength and low-ductility materials (such as PET), and the diameter hardly changes with the increase of pressure in a high-pressure environment, and can accurately maintain the preset size.

[0121] In the ablation surgery, the non-compliant balloon can ensure that the ablation energy is uniformly transmitted to the target tissue through the closely fitted balloon wall, and can avoid uneven energy distribution or tissue damage caused by excessive expansion of the balloon. In addition, the high burst pressure can safely withstand the high-pressure environment required by the surgery, and can stably support the integrated electrode or transducer to accurately position the ablation target, thereby improving the safety and effectiveness of the ablation surgery.

[0122] The application also provides a balloon catheter 1000 comprising the balloon 100 described above. Before introducing the specific content of the balloon catheter 1000 provided by the embodiments of the application, it should be pointed out in advance that, in order to verify the reliability of the balloon catheter 1000, the balloon catheter 1000 is subjected to simulation experiments, including acoustic simulation and biological heat simulation.

[0123] In order to verify the reliability of the balloon catheter 1000 provided by the embodiments of the application, a simulation model is first established, which can be modeled using COMSOL Multiphysics (COMSOL Multiphysics, Burlington, MA, USA). The modeling process is not described in detail here, but in order to enable those skilled in the art to restore the structure of the balloon catheter 1000 provided by the embodiments of the application, the application provides relevant parameters used in the modeling process (using a tubular ultrasonic transducer), as shown in Table 1.

[0124] Table 1

[0125] It should be noted that all simulation experiments provided by the embodiments of the application are carried out under the same voltage / power excitation conditions.

[0126] For the ultrasonic transducer, the working frequency of the ultrasonic transducer in the simulation experiments of the embodiments of the application is 8.5 MHz. Since the transducer works independently of the balloon 100, changes in the design of the balloon 100 will not affect the performance of the transducer. Under the same excitation power, the acoustic field generated by different balloons 100 remains consistent.

[0127] For the balloon 100 used in the simulation, the diameter is 4 mm. Clinically, due to the difference in blood vessel size, different balloon 100 sizes from 4 mm to 8 mm can be required. As the radius of the balloon 100 changes, the distance between the balloon 100 and the transducer also changes. However, through simulation experiments, it is found that when the size of the balloon 100 changes in the range of 4 mm to 8 mm, the acoustic field distribution characteristics do not change significantly.

[0128] In addition, the wave emitted by the transducer is similar to a cylindrical wave front. Since the ultrasonic attenuation effect of the circulating water in the balloon 100 is extremely small, as the radius increases, a divergence effect of reducing intensity can occur, but the effect on the shape of the acoustic field can be ignored. It should be noted that the tubular piezoelectric ceramic transducer used in the embodiments of the application, in actual application, uses other energy generators 200 in the shape of a prism, which is also within the protection scope of the embodiments of the application.

[0129] It is particularly noted that the embodiments of the present application in the bio-thermal simulation (Figs. 13-16 hereinafter) are based on the effectiveness and safety thresholds of ultrasound ablation defined in IEC 60601-2-62 (Medical electrical equipment - Part 2-62: Particular requirements for the basic safety and essential performance of high-intensity therapeutic ultrasound (HITU) equipment). The effective ablation threshold is characterized by a thermal dose (T43) of 1800 seconds, while the safety threshold corresponds to a thermal dose (T43) of 60 seconds. Within the 54°C isotherm range, the thermal dose of T43 exceeds 1800 seconds, meeting the effective ablation standard. Outside the 48°C isotherm, the thermal dose of T43 can be below 60 seconds, remaining below the safety threshold, ensuring the safety of adjacent tissues. The embodiments of the present application simulate the time required for several types of balloon catheters 1000 provided by the embodiments of the present application to reach 54°C at a 6mm ablation boundary, respectively, to study the temperature rise, i.e. the length of time required for the ablation procedure; and the distance of several balloon catheters 1000 provided by the embodiments of the present application from the blood vessel wall at the 48°C isotherm within a given ablation event, to study the impact on non-target areas.

[0130] The following is a specific content of the balloon catheter 1000 provided by the embodiments of the present application.

[0131] The balloon catheter 1000 includes a balloon 100, an energy generator 200, a first axial fixing member 300 and a second axial fixing member 400. Among them, the balloon 100 includes the balloon 100 provided by the first aspect of the present application, and the expanded state of the balloon 100 can refer to the foregoing, including: a first stretch section 110, a lens section 120 and a second stretch section 130; the lens section 120 is arranged between the first stretch section 110 and the second stretch section 130 along the axial direction (Y).

[0132] Taking the structural schematic diagram of a conventional balloon catheter as an example, the structure of the balloon catheter 1000 provided by the embodiments of the present application is introduced. Please refer to Fig. 5, which is a structural schematic diagram of a conventional balloon catheter 0; as shown in Fig. 5, the conventional balloon catheter 0 is to set the energy generator 200 in the hollow channel in the middle of the balloon 100.

[0133] Among them, the energy generator 200, in particular, the piezoelectric tubular transducer utilizes radially polarized piezoelectric ceramics, which exhibits a high efficiency of emitting ultrasonic power from the center to the outside. This feature realizes 360° energy convergence, which is applied to medical applications of intracavitary acoustic therapy (such as renal denervation ablation, RDN), which can improve the efficiency and effectiveness of the operation.

[0134] In FIG. 5, the transducer in the middle of the balloon catheter 1000 is a tubular piezoelectric ceramic transducer. Please refer to FIG. 6 and FIG. 13 in combination with FIG. 5, FIG. 6 is an acoustic simulation result diagram of a conventional balloon catheter provided by the embodiment of the present application; FIG. 13 is a bio-thermal simulation result diagram of a conventional balloon catheter provided by the embodiment of the present application; in FIG. 6, the horizontal axis is the radial dimension (unit, mm), the left vertical axis is the axial dimension (unit, mm), and the right vertical axis is the energy intensity (unit, Pa). As can be seen from FIG. 6, the focusing effect of the conventional balloon catheter is poor, and the energy is in a divergent shape. As shown in the bio-thermal simulation result in FIG. 13, it can be seen from FIG. 13 that the ablation time required by the conventional balloon catheter is 18 seconds, and the distance of the 48℃ isotherm of the conventional balloon catheter from the blood vessel wall is 8.1mm.

[0135] The balloon catheter 1000 provided by the embodiment of the present application, the energy generator 200 is arranged in the hollow channel of the lens segment 120, and the energy generator 200 has a length corresponding to the lens segment 120 in the axial direction (Y). It should be noted that the corresponding length means that the length of the lens segment 120 can be determined according to the length of the energy generator 200. Optionally, the length of the lens segment 120 in the axial direction (Y) can be set to be consistent with the length of the energy generator 200; optionally, the length of the lens segment 120 in the axial direction (Y) can be set to be slightly smaller than the length of the energy generator 200.

[0136] The first axial fixing member 300 is arranged in the hollow channel of the first extension segment 110 and is fixedly connected with the first end of the energy generator 200; the second axial fixing member 400 is arranged in the hollow channel of the second extension segment 130 and is fixedly connected with the second end of the energy generator 200. The fixing mode of the energy generator 200 can be referred to FIG. 5, which is similar to the fixing mode of the energy generator of the conventional balloon catheter, and the two ends of the energy generator 200 are fixed by the first axial fixing member 300 and the second axial fixing member 400.

[0137] The converging structure 121 of the lens segment 120 is configured to converge the energy generated by the energy generator 200 to a target converging area.

[0138] Different from the traditional balloon catheter, the balloon catheter 1000 provided in the embodiments of the present application has the energy generator 200 fixed in the hollow channel of the lens segment 120 of the balloon 100; the balloon 100 includes the first extended segment 110, the lens segment 120 and the second extended segment 130, wherein the lens segment 120 includes the converging structure 121 capable of converging the energy from the hollow channel of the lens segment 120 to the target converging area. Through the design of the converging structure 121, the energy can be converged to different depths, that is, the adjustment of the focal point is realized. The balloon catheter 1000 provided in the embodiments of the present application is used in the catheter for the interventional surgery, which can realize the precise ablation of the target ablation point; not only the precise convergence of the energy is realized, but also the temperature rising speed of the ablation point is improved, the time length of the ablation surgery is shortened, and the surgery experience of the patient is improved.

[0139] Please refer to FIG. 7 to FIG. 9, FIG. 7 is a structural schematic diagram of the Bessel type balloon catheter provided in the embodiments of the present application; FIG. 8 is a structural schematic diagram of the Fresnel type balloon catheter provided in the embodiments of the present application; FIG. 9 is a structural schematic diagram of the quasi-Bessel type balloon catheter provided in the embodiments of the present application; the converging structure 121 of the balloon 100 in the balloon catheter 1000 provided in the embodiments of the present application includes the first thickness segment 1211 with the thickness of the basic thickness d1 and the second thickness segment 1212 with the thickness of d2.

[0140] Wherein, the thickness d2 of the second thickness segment 1212 is the phase difference thickness d added on the basic thickness d1, that is, d2=d1+d; the phase difference thickness d is determined based on the phase difference between the adjacent wave groups generated by the energy generator 200.

[0141] The Bessel lens reconstructs the incident light wave front into a conical wave front by precisely controlling the phase delay difference between the adjacent annular wave groups, thereby generating the non-diffracting Bessel beam. Specifically, in the present application, the radial thickness of the balloon 100 is set to different sizes (the first thickness segment 1211 and the second thickness segment 1212), and the light waves have a certain phase difference at different thickness positions, so that the wave front forms a concentric annular interference in the propagation, and finally the central bright spot (the target converging area) of the Bessel beam is superimposed on the axis (perpendicular to the axial direction (Y)).

[0142] Exemplarily, taking the ultrasonic transducer as an example, the phase difference Δφ=π is defined. The phase difference thickness d can be obtained based on the following formula:

[0143]

[0144] wherein c w is the speed of ultrasound propagation in tissue, c p is the speed of ultrasound propagation in the balloon 100, and f is the operating frequency. In addition, for a conventional balloon, the base thickness d1 is generally 0.05 mm. Using a balloon 100 with a diameter of 4 mm, with a focal length of 6 mm (in a denervation ablation procedure, it is considered that the position where the nerve distribution is the most concentrated, taking the RDN operation as an example, the target ablation area is the radial range of 6 mm away from the artery, which can effectively cover more than 95% of the renal arterial nerves), taking c w = 1500 m / s, c p = 2250 m / s, f = 8.5 MHz, the phase difference thickness d is calculated to be 0.265 mm. _ w = 1500 m / s, c p = 2250 m / s, f = 8.5 MHz, the phase difference thickness d is calculated to be 0.265 mm.

[0145] As can be seen from FIGS. 7 to 9, the converging structure 121 of the balloon 100 in the balloon catheter 1000 provided in the embodiments of the present application is a binary distribution thickness design, which can endow the lens segment 120 with the acoustic characteristics of a Bessel or Fresnel lens, and by adjusting the number of the first thickness segment 1211 and the second thickness segment 1212, the distribution of energy (such as energy emitted by an ultrasonic transducer) from the hollow channel of the balloon 100 can be controlled. In a denervation ablation procedure, the application of the balloon catheter 1000 provided in the embodiments of the present application can accurately focus energy on a target ablation area, effectively reduce the duration of the ablation procedure, and improve the comfort of the patient during the procedure.

[0146] Please refer to FIGS. 7 and 9, FIG. 7 shows a Bessel balloon catheter 1000 and FIG. 9 shows a quasi-Bessel balloon catheter 1000, wherein the length of the first thickness segment 1211 and the second thickness segment 1212 in the axial direction (Y) is approximately equal to or equal to the phase difference thickness d.

[0147] For example, in the above implementation process, the calculated phase difference thickness d = 0.265 mm is calculated, and then the length of each first thickness segment 1211 and second thickness segment 1212 in the axial direction (Y) can be designed in combination with the axial length of the ultrasonic transducer, for example, by calculating the length of each first thickness segment 1211 and second thickness segment 1212 in the axial direction (Y) to be 0.26 mm.

[0148] In the Bessel balloon catheter 1000 and the quasi-Bessel balloon catheter 1000 provided in the embodiments of the present application, for each first thickness segment 1211 and second thickness segment 1212, the length thereof in the axial direction (Y) is set to be approximately equal to or equal to the phase difference thickness d, which can achieve accurate notification of linear phase delay and generate a non-diffractive Bessel beam.

[0149] Please continue to refer to FIG. 7, in the balloon catheter 1000 provided by the embodiments of the present application, the converging features presented by the converging structure 121 of the Bessel balloon catheter 1000 are consistent with the converging features of a Bessel lens.

[0150] The number of the first thickness segments 1211 and the second thickness segments 1212 are n and n+1 respectively. Wherein, n is determined based on the position of the target converging area. FIG. 7 is an example, the number of the first thickness segments 1211 is n, and the number of the second thickness segments 1212 is n+1; the arrangement corresponding to the axial direction (Y) is: second thickness segment 1212-first thickness segment 1211-second thickness segment 1212…first thickness segment 1211-second thickness segment 1212. In some possible embodiments, the number of the first thickness segments 1211 can be set to n+1, and the number of the second thickness segments 1212 can be set to n; the arrangement corresponding to the axial direction (Y) is: first thickness segment 1211-second thickness segment 1212-first thickness segment 1211-second thickness segment 1212…first thickness segment 1211-second thickness segment 1212-first thickness segment 1211.

[0151] Therefore, it can be seen that the Bessel balloon catheter 1000 provided by the embodiments of the present application, the lens segment 120 of the entire balloon 100 is covered with the converging structure 121, the first thickness segments 1211 and the second thickness segments 1212 are staggered in the converging structure 121, and the length of the first thickness segments 1211 and the second thickness segments 1212 in the axial direction (Y) is consistent. The number of the first thickness segments 1211 and the second thickness segments 1212 can be designed to adjust the distribution of energy from the hollow channel of the balloon 100.

[0152] Please refer to FIG. 10 and FIG. 14 on the basis of FIG. 7, FIG. 10 is an acoustic simulation result diagram of the Bessel balloon catheter provided by the embodiments of the present application; FIG. 14 is a biological heat simulation result diagram of the Bessel balloon catheter provided by the embodiments of the present application; in the optional implementation of the embodiments of the present application, the converging structure 121 includes n first thickness segments 1211 and n+1 second thickness segments 1212.

[0153] In the case that the distance between the center point of the target converging area position and the outer surface of the lens segment 120 in the radial direction (R) is between [5.7mm, 6.3mm], n is 11. Preferably, the distance between the center point of the target converging area position and the basic thickness of the outer surface of the lens segment 120 in the radial direction (R) is controlled to be 6mm, which is the best.

[0154] For example, as shown in FIG. 7, according to the requirements of RDN, the target ablation area is a radial range of 6 mm from the artery, and more than 95% of the renal artery nerves are effectively covered. For the Bezier balloon 100, the first thickness section 1211 and the second thickness section 1212 of the embodiment of the application are 0.26 mm (approximately phase difference thickness d, the calculation result of the above phase difference thickness d is 0.265), which presents a "ring gap" structure in vision. In FIG. 7, there are 12 second thickness sections 1212 and 11 first thickness sections 1211 on the balloon 100, which can achieve the desired focal length of 6 mm.

[0155] To verify the reliability of the structure of FIG. 7, the embodiment of the application carries out acoustic simulation, and the acoustic simulation result of the Bezier balloon catheter 1000 is shown in FIG. 10. In FIG. 10, the horizontal axis is the radial dimension (unit, mm), the left vertical axis is the axial dimension (unit, mm), and the right vertical axis is the energy intensity (unit, Pa). As can be seen from FIG. 10, the Bezier lens balloon 100 appears a converging mode of a triangular area at a depth of 6 mm, which can achieve the energy convergence of the target ablation area required for RDN surgery.

[0156] and biological heat simulation. As can be seen from the biological heat simulation result shown in FIG. 14, the ablation time required by the Bezier balloon catheter 1000 is 25 seconds, and the distance of the 48℃ isotherm of the Bezier balloon catheter 1000 from the blood vessel wall is 7.1 mm. The influence on the non-target area is very small, which can achieve a safe ablation surgery.

[0157] As can be seen from FIG. 7, FIG. 10 and FIG. 14, the balloon catheter 1000 provided by the embodiment of the application includes the Bezier balloon catheter 1000, and the converging feature presented by the converging structure 121 is consistent with the converging feature of the Bezier lens. The embodiment of the application provides an example of RDN surgery, and the parameters are designed and adjusted. After simulation, it can be verified that the Bezier balloon catheter 1000 provided by the embodiment of the application can achieve the energy convergence of the target ablation area required for RDN surgery.

[0158] Please refer to FIG. 11 and FIG. 15 on the basis of FIG. 9, FIG. 11 is an acoustic simulation result diagram of a quasi-Bezier balloon catheter provided by the embodiment of the application; and FIG. 15 is a biological heat simulation result diagram of the quasi-Bezier balloon catheter provided by the embodiment of the application. In the balloon catheter 1000 provided by the embodiment of the application, the converging feature presented by the converging structure 121 of the quasi-Bezier balloon catheter 1000 is consistent with the converging feature of the quasi-Bezier lens.

[0159] Figure 9 shows a schematic diagram of a quasi-Bessel balloon catheter 1000. It should be noted that a quasi-Bessel lens can approximate the key characteristics of a Bessel beam, while overcoming the complexity and energy loss problems of traditional Bessel beam generation methods through simplified structure. The quasi-Bessel balloon 100 shown in Figure 9 is a simplified version of the Bessel balloon 100 structure shown in Figure 7. The first thickness section 1211 and the second thickness section 1212 in the focusing structure of the lens section 120 in Figure 7 are removed, resulting in the intermediate length section 122 described above. The first thickness section 1211 and the second thickness section 1212 on both sides of the intermediate length section 122 have the same length in the axial direction (Y). By designing the number and size of the first thickness section 1211 and the second thickness section 1212 on both sides, the energy distribution from the energy generator 200 in the hollow channel of the balloon 100 can be controlled.

[0160] In the above implementation process, the intermediate length section 122 of the lens section 120 is determined based on the position of the target convergence region.

[0161] Still taking the RDN procedure as an example, the target ablation region is a radial range of 6 mm from the artery, effectively covering more than 95% of the renal artery nerves. Taking the quasi-Bessel balloon 100 shown in Figure 9 as an example, three rings (second thickness sections 1212) are retained on each side, and the center six rings (second thickness sections 1212) are removed. Thus, the transducer is effectively divided into upper, middle, and lower parts, with the middle part corresponding to the peripheral tissue region, which is the main ablation target region. The ultrasound waves emitted by this part of the transducer directly penetrate and interact with the target region. At the same time, the transducer parts located in the upper and lower parts use Bessel acoustic structure, which helps to refract part of the energy to the middle target region. Therefore, the energy received by the middle target region is greater than the original energy.

[0162] To verify the reliability of the balloon catheter 1000 shown in Figure 9, the present embodiment provides a schematic diagram of the acoustic simulation results of the structure in Figure 9. The acoustic simulation results of the quasi-Bessel balloon catheter 1000 are shown in Figure 11. In Figure 11, the horizontal axis is the radial dimension (unit, mm), the left vertical axis is the axial dimension (unit, mm), and the right vertical axis is the energy intensity (unit, Pa). As can be seen from Figure 11, the quasi-Bessel lens balloon 100 has a significant convergence effect at a depth of 6 mm, and can achieve energy convergence for the target ablation region required for RDN procedures.

[0163] and bio-thermal simulation. As can be seen from the bio-thermal simulation results shown in FIG. 16, the ablation time required for the quasi-Bessel balloon catheter 1000 is 14 seconds, which is about 22% less than the ablation time of the conventional balloon catheter 0; the distance of the 48°C isotherm of the quasi-Bessel balloon catheter 1000 from the blood vessel wall is 7.8 mm. The quasi-Bessel balloon catheter 1000 has less impact on non-target regions and can achieve a safe ablation procedure.

[0164] As can be seen from FIGS. 9, 11 and 16, the converging feature presented by the converging structure 121 of the quasi-Bessel balloon catheter 1000 is consistent with the converging feature of a quasi-Bessel lens. In the present embodiment, the first thickness section 1211 and the second thickness section 1212 in the middle of the quasi-Bessel balloon catheter 1000 are adjusted taking the RDN procedure as an example. Simulation can verify that the quasi-Bessel balloon catheter 1000 provided in the present embodiment can achieve energy convergence on the target ablation region required for the RDN procedure, and the structure is simple and has strong manufacturability, thereby providing strong and reliable support for ablation procedures.

[0165] Please refer to FIGS. 12 and 15 on the basis of FIG. 8. FIG. 12 is an acoustic simulation result diagram of a Fresnel balloon catheter provided in the present embodiment; and FIG. 15 is a bio-thermal simulation result diagram of a Fresnel balloon catheter provided in the present embodiment. In the balloon catheter 1000 provided in the present embodiment, the converging feature presented by the converging structure 121 of the Fresnel balloon catheter 1000 is consistent with the converging feature of a Fresnel lens.

[0166] In the present embodiment, the lengths of the first thickness section 1211, the second thickness section 1212 and the intermediate length section 122 in the axial direction (Y) are determined according to the Fresnel zone plate formula based on the position of the target converging region.

[0167] In the present embodiment, for the Fresnel balloon catheter 1000, the length in the axial direction (Y) is determined according to the following formula:

[0168]

[0169] where F_L is the focal depth of 6 mm, and λ is the wavelength of the ultrasound in the tissue. According to the length of the transducer (Table 1), the maximum value of N is 7. Therefore, the path length from the "focus" to the boundary of any ring (second thickness section 1212) is longer than an integer multiple of the half wavelength λ of F_L.

[0170] To verify the reliability of the balloon catheter 1000 shown in FIG. 8, the acoustic simulation results of the structure in FIG. 8 are provided. The acoustic simulation results of the Fresnel balloon catheter 1000 are shown in FIG. 12. In FIG. 12, the horizontal axis is the radial dimension (unit, mm), the left vertical axis is the axial dimension (unit, mm), and the right vertical axis is the energy intensity (unit, Pa). As can be seen from FIG. 12, the Fresnel balloon 100 has a significant convergence effect at a depth of 6 mm, and can achieve energy convergence of the target ablation area required for RDN surgery.

[0171] and bio-thermal simulation. As can be seen from the bio-thermal simulation results shown in FIG. 15, the ablation time required for the quasi-Bessel balloon catheter 1000 is 14 seconds, which is about 22% less than the ablation time of the conventional balloon catheter 0; the distance of the 48°C isotherm of the Fresnel balloon catheter 1000 from the blood vessel wall is 7.3 mm. It has less effect on non-target areas and can achieve safe ablation surgery.

[0172] As can be seen from FIGS. 8, 12 and 15, the Fresnel balloon catheter 1000 provided in the embodiments of the present application has a convergence feature consistent with the convergence feature of a Fresnel lens. The embodiments of the present application take RDN surgery as an example to calculate the lengths of the first thickness section 1211 and the second thickness section 1212 in the middle of the Fresnel balloon catheter 1000. It can be verified through simulation that the Fresnel balloon catheter 1000 provided in the embodiments of the present application can achieve energy convergence of the target ablation area required for RDN surgery, and the structure is simple and has strong manufacturability, which can significantly shorten the duration of ablation surgery and provide strong and reliable support for ablation surgery.

[0173] Please refer to FIG. 17 on the basis of FIGS. 5 to 8, which is a temperature change curve diagram of a 6 mm radial position provided in the embodiments of the present application; in FIG. 17, the horizontal axis is time (unit, s), and the vertical axis is temperature change of a 6 mm radial position (unit, °C). The black square marker line is the temperature change curve of the conventional balloon catheter 0, the red circle marker line is the temperature change curve of the Bessel balloon catheter 1000, the blue equilateral triangle marker line is the temperature change curve of the Fresnel balloon catheter 1000, and the pink inverted triangle marker line is the temperature change curve of the quasi-Bessel balloon catheter 1000. As can be seen from FIG. 17, the slopes of the Fresnel balloon catheter 1000 and the quasi-Bessel balloon catheter 1000 are the same and the highest, indicating that the temperature rising rate is the fastest. The temperatures of these two balloons 100 are 2-4°C higher than that of the conventional balloon catheter 0, which has a significant advantage in shortening the duration of ablation surgery.

[0174] Please refer to FIG. 18 based on FIGS. 5-8, which is a schematic diagram of temperature distribution of the transducer axial center position 14 seconds later according to an embodiment of the present application. In FIG. 18, the horizontal axis is the radial distance (unit: mm), and the vertical axis is the temperature (unit: °C). The black square mark line is the temperature curve of the traditional balloon catheter 0, the red circle mark line is the temperature curve of the Bezier balloon catheter 1000, the blue triangle mark line is the temperature curve of the Fresnel balloon catheter 1000, and the lilac inverted triangle mark line is the temperature curve of the quasi-Bezier balloon catheter 1000. As can be seen from FIG. 18, within the range of 1.5 mm, the temperatures of the four balloons 100 are similar. Within the range of 1.5-2.5 mm, the temperatures of the Fresnel balloon catheter 1000 and the quasi-Bezier balloon catheter 1000 are the highest and similar, the temperature of the Bezier balloon catheter 1000 is slightly lower but still higher than that of the traditional balloon. Within the range of 2.5-6 mm, the temperatures of the Fresnel balloon catheter 1000 and the quasi-Bezier balloon catheter 1000 are similar, about 3°C higher than that of the traditional balloon, and the temperature of the Bezier balloon catheter 1000 is slightly lower than that of the traditional balloon. Beyond 6 mm, the temperatures of the Fresnel balloon catheter 1000, the quasi-Bezier balloon catheter 1000 and the traditional balloon catheter 0 are similar.

[0175] Please refer to FIGS. 19 and 20. FIG. 19 is a comparison diagram of transducer radial sound field distribution according to an embodiment of the present application. FIG. 20 is a diagram of sound pressure amplification at 6 mm according to an embodiment of the present application. In FIG. 19, the horizontal axis is the radial distance (unit: mm), and the vertical axis is the absolute sound pressure (unit: MPa). The black line is the absolute sound pressure curve of the traditional balloon catheter 0, the red line is the absolute sound pressure curve of the Bezier balloon catheter 1000, the blue line is the absolute sound pressure curve of the Fresnel balloon catheter 1000, and the lilac line is the absolute sound pressure curve of the quasi-Bezier balloon catheter 1000. In FIG. 20, the vertical axis is the sound pressure intensity at 6 mm (unit: A.U.). The red column is the sound pressure intensity of the traditional balloon catheter 0, the green column is the sound pressure intensity of the Bezier balloon catheter 1000, the dark blue column is the sound pressure intensity of the Fresnel balloon catheter 1000, and the light blue column is the sound pressure intensity of the quasi-Bezier balloon catheter 1000.

[0176] As can be seen from the figures, compared with the traditional balloon, the balloon 100 equipped with the lens has a wave peak at about 6 mm. As shown in FIG. 20, the sound pressure intensity at 6 mm is normalized and compared with that of the traditional balloon. It is found that the sound intensity amplification of the Fresnel lens balloon 100 is the largest, about twice that of the traditional balloon; the quasi-Bezier lens balloon 100 is second, with an amplification of 100%; and the Bezier lens balloon 100 has an amplification of about 50%. Compared with the traditional balloon, the three lens balloons 100 all have a significant sound intensity peak at 6 mm.

[0177] From the simulation results above, it can be seen that the Fresnel balloon catheter 1000 and the quasi-Bessel balloon catheter 1000 provided by the embodiments of the present application have a significantly better heating effect than the traditional balloon catheter, and can reach an effective ablation temperature in a shorter time. From a clinical perspective, this means that the patient's pain tolerance time is shortened, and the overall treatment comfort is improved.

[0178] In an optional embodiment of the embodiments of the present application, the position of the target converging area is determined according to the target physiological position to be ablated.

[0179] For example, in the treatment of refractory hypertension, the ablation energy needs to be accurately applied to the sympathetic nerve fibers of the adventitia of the renal artery. The ablation catheter (such as a radiofrequency or an ultrasonic balloon catheter 1000 provided by the embodiments of the present application) will converge energy to a specific circumferential area of the blood vessel wall to form a ring-shaped ablation zone, thereby destroying the overactive nerve signal conduction while avoiding damage to the intima of the blood vessel or the adjacent kidney parenchyma.

[0180] Optionally, the target physiological position targeted by the embodiments of the present application includes the sympathetic nerve position or parasympathetic nerve position of the renal artery, duodenum, celiac artery, abdominal aorta, common hepatic artery, and proper hepatic artery.

[0181] The position of the target converging area of the balloon catheter 1000 provided by the embodiments of the present application is determined according to the target physiological position to be ablated. Based on the determination of the converging position of the energy based on the physiological position, precise ablation is achieved, and the safety and effectiveness of the treatment are significantly improved. Both the target tissue can be destroyed and the surrounding healthy structure can be protected to the maximum extent; the balloon catheter 1000 provided by the embodiments of the present application can significantly improve the surgical precision, efficiency and safety of ablation procedures for complex diseases such as metabolic syndrome and intractable visceral pain, and promote the development of minimally invasive surgery towards high precision.

[0182] The embodiments of the present application also provide an ablation catheter, which comprises an energy generator, a first axial fixing member, a second axial fixing member, and a balloon having a first extended section, a lens section and a second extended section in an expanded state.

[0183] The lens section is arranged between the first and second extended sections, and the radial dimensions of the first and second extended sections increase in the direction of the lens section in the axial direction and are connected to the lens section. As shown in the balloon structure shown in FIGS. 7 to 9, the first and second extended sections are tapered, and the radial dimensions gradually increase towards the lens section.

[0184] The energy generator is arranged in the hollow channel of the lens segment; the first axial fixing member is arranged in the hollow channel of the first extension segment and fixedly connected with the first end of the energy generator; and the second axial fixing member is arranged in the hollow channel of the second extension segment and fixedly connected with the second end of the energy generator.

[0185] As shown in FIGS. 7-9, the length of the energy generator in the axial direction of the lens segment is equal. The converging structure of the lens segment is configured to converge the energy generated by the energy generator to a target converging area.

[0186] The embodiments of the present application successfully develop the configurations of Bessel and Fresnel lenses by realizing the periodic function distribution of axial binary thickness in the balloon. The balloon provided by the embodiments of the present application is endowed with the optical structural characteristics of Bessel and Fresnel lenses, and can effectively focus acoustic energy on a suitable focal depth. When the balloon provided by the embodiments of the present application is applied to ablation surgery, the acoustic pressure is significantly increased at the ablation radius, and the temperature rise time is effectively shortened, thereby significantly reducing the time length of the ablation surgery and significantly improving the surgical effect.

[0187] Referring to FIG. 21, in the embodiment, a tubular ultrasonic weak focusing device is provided, which includes a balloon 1, a transducer 2 arranged in the balloon 1, the transducer 2 connected with an inner tube 3, and a balloon cavity between the transducer 2 and the inner wall of the balloon 1, and the balloon cavity can be supplied with cooling liquid through the inner tube 3.

[0188] The acoustic beam adjusting structure is distributed along the axial direction of the balloon 1; the acoustic beam passes through the balloon 1 and the acoustic beam adjusting structure to form an adjustable weak focusing area outside the balloon 1, so that the ablation depth and precision are adjustable and the target area has the characteristics of synchronous temperature rise.

[0189] In an embodiment, the acoustic beam adjusting structure includes at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are located on the balloon wall of the balloon 1.

[0190] In an embodiment, the acoustic beam adjusting structure includes at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are located on the outer wall of the transducer 2.

[0191] In an embodiment, the acoustic beam adjusting structure includes at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are located in the region between the transducer 2 and the balloon 2.

[0192] It can be understood that the acoustic unit structure is synchronized with the balloon 1 to enter the blood vessel, and does not have relative displacement with the transducer 2 or the balloon 1, so that the acoustic beam can pass through the acoustic unit structure and the balloon 1 to form an adjustable weak focusing area outside the balloon 1.

[0193] Further, the acoustic unit structures are arranged in at least multiple groups in axial symmetry along the balloon 1, and the at least multiple groups of acoustic unit structures are located at two ends of the balloon 1.

[0194] Further, the acoustic unit structure comprises a first medium 41 and a second medium 42, the first medium 41 and the second medium 42 are arranged in a spaced manner, the sizes of the first medium 41 and the second medium 42 are adjacent, the first medium 41 is annular and arranged on the outer wall of the balloon 1 in an axial direction, and the first medium 41 is made of the same material as the balloon 1.

[0195] By increasing the ultrasonic frequency of the adjusting transducer 2, the greater the ultrasonic frequency, the greater the ablation range or depth, and the spacing between the multiple groups of acoustic unit structures, the length or width of each acoustic unit structure can also be adjusted, thereby adjusting the focusing depth and width of the weak focusing area, forming a weak focusing area that can adjust the ablation depth and accuracy and the characteristics of synchronous temperature rise in the target area, and has the advantages of uniform ablation effect and obvious far-end boundary, which can realize precise ablation of the renal artery branches and trunks, not only ensures the thoroughness of ablation, but also minimizes the damage to the surrounding normal tissues, meets the clinical requirement of "ablation as much as possible", and improves the effectiveness and safety of treatment.

[0196] In a specific embodiment, referring to FIGS. 22-24, the sound beam adjusting structure comprises a first acoustic unit structure 4 and a second acoustic unit structure 5, the first acoustic unit structure 4 and the second acoustic unit structure 5 are respectively located at two ends of the balloon 1, the first acoustic unit structure 4 and the second acoustic unit structure 5 are arranged in axial symmetry along the balloon 1, and the first acoustic unit structure 4 and the second acoustic unit structure 5 have a gap therebetween.

[0197] In this embodiment, the balloon cavity between the first acoustic unit structure 4 and the transducer 2 forms a first coherence area 102, the width of the first coherence area 102 is adjacent to the length of the first acoustic unit structure 4, and the first sound beam is formed in the first coherence area 102 when the transducer 2 is working, and the first sound beam propagates along the radial direction of the balloon 1.

[0198] After the first sound beam passes through the balloon 1 and the first acoustic unit structure 4, refraction occurs in the first acoustic unit structure 4 to form two sound beams, including a fourth sound beam and a fifth sound beam:

[0199] The fourth sound beam propagates in a direction that forms an obtuse angle with the radial direction of the balloon 1, which can be understood as the fourth sound beam propagates in a direction away from the radial center axis of the balloon 1.

[0200] The fifth sound beam propagates in a direction that forms an acute angle with the radial direction of the balloon 1, which can be understood as the fifth sound beam propagates in a direction close to the radial center axis of the balloon 1.

[0201] In the embodiment, the balloon cavity between the second acoustic unit structure 5 and the transducer 2 forms a second coherent zone 103, the width of the second coherent zone 103 is adjacent to the length of the second acoustic unit structure 5, and the third sound beam is formed in the second coherent zone 103 when the transducer 2 works, and the third sound beam propagates along the radial direction of the balloon 1.

[0202] After the second sound beam passes through the balloon 1 and the second acoustic unit structure 5, two additional sound beams are formed by refraction at the second acoustic unit structure 5, including a sixth sound beam and a seventh sound beam:

[0203] The seventh sound beam propagates in a direction that forms an obtuse angle with the meridian direction of the balloon 1, and it can be understood that the seventh sound beam propagates in a direction away from the radial center axis of the balloon 1.

[0204] The sixth sound beam propagates in a direction that forms an acute angle with the radial direction of the balloon 1, and it can be understood that the sixth sound beam propagates in a direction close to the radial center axis of the balloon 1.

[0205] In the embodiment, the balloon cavity at the spacing between the first acoustic unit structure 4 and the second acoustic unit structure 5 forms a free propagation zone 101, the width of the free propagation zone 101 is adjacent to the length of the spacing between the first acoustic unit structure 4 and the second acoustic unit structure 5, and the second sound beam is formed in the free propagation zone 101 when the transducer 2 works, and the second sound beam propagates along the radial direction of the balloon 1.

[0206] After the second sound beam passes through the balloon 1, the medium outside the balloon 1 at the free propagation zone 101 is the human tissue of the blood vessel inner wall, and the second sound beam will not be significantly refracted. The second sound beam, the fifth sound beam, and the sixth sound beam form a weak focusing area with a larger width close to the balloon 1 and a smaller width away from the balloon 1, and it can be understood that the longitudinal axis of the weak focusing area forms a shape adjacent to a trapezoidal structure, and it can be further known that the first acoustic unit structure 4 and the second acoustic unit structure 5 are symmetrically arranged, so that the formed trapezoidal structure is adjacent to an isosceles trapezoidal structure, which is used for ablation of the treatment target area.

[0207] Currently, in order to improve the range or depth of ablation, the technical means adopted is to increase the frequency of the transducer 2, the greater the frequency of the ultrasonic wave, the greater the range or depth of ablation, but the disadvantage is that the mechanical wave vibration makes the tissue heat up more, and the accuracy of ablation is also reduced.

[0208] In the embodiment, the positions of the first acoustic unit structure 4 and the second acoustic unit structure 5 in the axial direction of the balloon 1 can be adjusted, the spacing between the first acoustic unit structure 4 and the second acoustic unit structure 5 can be adjusted, and the width close to the balloon 1 and the width away from the balloon 1 of the weak focusing area can be adjusted.

[0209] When the distance between the first acoustic unit structure 4 and the second acoustic unit structure 5 is greater, the width of the incident surface of the weak focusing region near the balloon 1 is greater, the width of the incident surface of the weak focusing region far from the balloon 1 is greater, the ablation region is greater, and the precision of ablation is relatively reduced.

[0210] When the distance between the first acoustic unit structure 4 and the second acoustic unit structure 5 is smaller, the width of the incident surface of the weak focusing region near the balloon 1 is smaller, the width of the incident surface of the weak focusing region far from the balloon 1 is smaller, the ablation region is smaller, and the precision of ablation is relatively improved.

[0211] Further, the height of the first acoustic unit structure 4 and the second acoustic unit structure 5 in the axial direction of the balloon 1 can be adjusted. By adjusting the height of the first acoustic unit structure 4 and the second acoustic unit structure 5, the width of the incident surface of the weak focusing region near the balloon 1 and the width of the incident surface of the weak focusing region far from the balloon 1 can be adjusted.

[0212] When the height of the first acoustic unit structure 4 and the second acoustic unit structure 5 is greater, the width of the incident surface of the weak focusing region near the balloon 1 is greater, the width of the incident surface of the weak focusing region far from the balloon 1 is greater, the ablation region is greater, and the precision of ablation is relatively reduced.

[0213] When the height of the first acoustic unit structure 4 and the second acoustic unit structure 5 is smaller, the width of the incident surface of the weak focusing region near the balloon 1 is smaller, the width of the incident surface of the weak focusing region far from the balloon 1 is smaller, the ablation region is smaller, and the precision of ablation is relatively improved.

[0214] Further, the width of the first acoustic unit structure 4 and the second acoustic unit structure 5 in the horizontal direction can be adjusted. When the axial position of the first acoustic unit structure 4 and the second acoustic unit structure 5 relative to the balloon 1 is fixed and the depth of the weak focusing region is certain, by adjusting the width of the first acoustic unit structure 4 and the second acoustic unit structure 5, the distance between the first acoustic unit structure 4 and the second acoustic unit structure 5 and the incident surface of the treatment region can be adjusted, and the focusing depth can be adjusted.

[0215] By adjusting the frequency of the ultrasonic wave, the distance between the acoustic structure and the incident surface of the treatment region, the number of the first acoustic unit structure 4 and the second acoustic unit structure 5, the height or width of the first acoustic unit structure 4 and the second acoustic unit structure 5, the focusing depth can be changed in the range of 3-10 mm, wherein the focusing depth is the radial distal end of the axial symmetry center, and the field strength is 1 / 2 of the peak field strength of the treatment region.

[0216] In the embodiment, the weak focusing area formed by the first acoustic unit structure 4 and the second acoustic unit structure 5 makes the ablation depth and precision adjustable, has the characteristics of synchronous temperature rise in the target area, and has the advantages of uniform ablation effect and obvious distal boundary, which can realize precise ablation of the renal artery branches and trunks, ensure the thoroughness of ablation, and minimize the damage to the surrounding normal tissues, meet the clinical requirement of "ablation as much as possible", and improve the effectiveness and safety of treatment.

[0217] It can be understood that in other embodiments, the first acoustic unit structure 4 and the second acoustic unit structure 5 can also be asymmetrically arranged in specific implementation, the height and width of the first acoustic unit structure 4 and the second acoustic unit structure 5 can be different, and the longitudinal axis of the weak focusing area formed is also a trapezoidal structure, which is used for ablation of the target treatment area.

[0218] In the embodiment, the transducer 2 is a tubular transducer, and the transducer 2 is sleeved on the inner tube 3 in the axial direction, which has the advantages of simple structure, low cost and stable working performance.

[0219] Further, the second acoustic unit structure 5 is symmetrically arranged with the first acoustic unit structure 4, the first acoustic unit structure 4 includes a first medium 41 and a second medium 42, one first medium 41 and one second medium 42 form a minimum unit, and the first medium 41 and the second medium 42 are adjacent in size, a plurality of minimum units are arranged to form the first acoustic unit structure 4, the corresponding material sound speed of the first medium 41 is C1, the corresponding material sound speed of the second medium 42 is C2, the transducer 2 emits a sound wave frequency f, the preset height of the minimum unit formed by the first medium 41 and the second medium 42 is d,

[0220]

[0221] When the beam propagates in the minimum unit with a height d, the split beams of the first medium 41 and the second medium 42 will produce a phase difference close to 1 / 2π-3 / 2π, preferably, the split beams of the first medium 41 and the second medium 42 produce a phase difference close to π, and the width w of the minimum unit is equal to or close to d.

[0222] In the embodiment, the first medium 41 is the same as the material of the balloon 1, the first medium 41 is annularly arranged on the outer wall of the balloon 1, a plurality of annular first media 41 are arranged on the outer wall of the balloon 1 in the axial direction, and there is a gap between the adjacent two first media 41.

[0223] In an embodiment, the first medium 41 and the balloon 1 are both made of nylon, and the first medium 41 is integrally formed with the balloon 1, which can save processing cost.

[0224] In the embodiment, the second medium 42 is the blood vessel wall human tissue, the balloon 1 enters the blood vessel, and the blood vessel wall human tissue is embedded in the gap between the first medium 41 to form the second medium 42.

[0225] In the implementation, during the treatment, the transducer 2 generates the sound beam, the first sound beam is refracted by the first medium 41 and the second medium 42 of the first acoustic unit structure 4 to form two sound beams, including the fourth sound beam and the fifth sound beam:

[0226] The fourth sound beam propagates in the direction of the obtuse angle with the radial angle of the balloon 1, and it can be understood that the fourth sound beam propagates in the direction away from the radial center axis of the balloon 1.

[0227] The fifth sound beam propagates in the direction of the acute angle with the radial angle of the balloon 1, and it can be understood that the fifth sound beam propagates in the direction close to the radial center axis of the balloon 1.

[0228] After the second sound beam passes through the balloon 1 and the second acoustic unit structure 5, the second sound beam is refracted by the second acoustic unit structure 5 to form two sound beams, including the sixth sound beam and the seventh sound beam:

[0229] The seventh sound beam propagates in the direction of the obtuse angle with the radial angle of the balloon 1, and it can be understood that the seventh sound beam propagates in the direction away from the radial center axis of the balloon 1.

[0230] The sixth sound beam propagates in the direction of the acute angle with the radial angle of the balloon 1, and it can be understood that the sixth sound beam propagates in the direction close to the radial center axis of the balloon 1.

[0231] After the second sound beam passes through the balloon 1, because the medium outside the balloon 1 at the free propagation area 101 is the blood vessel wall human tissue, the second sound beam does not have obvious refraction phenomenon, the second sound beam, the fifth sound beam and the sixth sound beam form a weak focusing area with a larger incident surface width close to the balloon 1 and a smaller incident surface width away from the balloon 1, and it can be understood that the shape of the longitudinal axis of the weak focusing area is adjacent to a trapezoidal structure, and it can be further understood that because the first acoustic unit structure 4 and the second acoustic unit structure 5 are symmetrically arranged, the formed trapezoidal structure is adjacent to an isosceles trapezoidal structure, and is used for ablation on the treatment target area.

[0232] Referring to FIG. 25, FIG. A is a comparison of the sound field distribution generated by the transducer in the prior art, and the balloon is not provided with a sound beam adjusting structure.

[0233] FIG. B is a sound field with a very obvious weak focusing area generated by the transducer in the present application, and the balloon is provided with a sound beam adjusting structure.

[0234] The present application also provides a tubular ultrasonic weak focusing method, which adopts the above-mentioned tubular ultrasonic weak focusing device to ablate the treatment target area.

[0235] Referring to Figure 26, Figure A shows the uniform temperature distribution when a conventional ultrasonic ablation catheter is used for 5 seconds in the prior art.

[0236] Figure B shows the invention where the balloon is equipped with a sound beam adjustment structure, resulting in a distinct weak focusing area in the temperature field.

[0237] Referring to Figures 27-28, in Figure A, the conventional ultrasound ablation catheter in the prior art expands the temperature rise from the inside to the outside in the treatment area, and the temperature rise time is relatively long.

[0238] Figure B illustrates the invention where the balloon is equipped with a sound beam adjustment structure, allowing the ultrasonic ablation catheter to simultaneously heat up the treatment area. Furthermore, the heating time is shorter, resulting in a greater radial ablation depth and better efficacy. A bulge is generated at 3-4 mm, reflecting the focusing effect.

[0239] Referring to Figure 29, the ultrasonic ablation catheter of the present invention has a temperature rise rate of approximately 1.5-2 times that of conventional ultrasonic ablation catheters in the initial stage (within 4 seconds), and the temperature rise is faster.

[0240] Understandably, the tubular ultrasound weak focusing device of this application can also be applied to renal artery denervation for hypertension, pulmonary artery denervation for pulmonary hypertension, hepatic artery denervation for diabetes, visceral nerve ablation for heart failure, and targeted lung denervation for COPD.

[0241] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0242] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A balloon characterized in that, The expanded state of the balloon comprises a first extended section, a lens section, and a second extended section; The lens section is disposed between the first and second extended sections along an axial direction; The lens section comprises a converging structure made of an energy-transmissive material; The converging structure is configured to converge energy from the hollow channel in the lens section to a target converging region.

2. The balloon of claim 1, wherein, The converging structure comprises a plurality of first thickness sections and a plurality of second thickness sections; The first and second thickness sections have different radial dimensions; The plurality of first thickness sections and the plurality of second thickness sections are staggered in the axial direction.

3. The balloon of claim 1, wherein, The lens section comprises an intermediate length section; The intermediate length section is disposed at an axial middle portion of the lens section, and the converging structure is disposed on both sides of the intermediate length section.

4. The balloon of claim 1, wherein, The balloon is a non-compliant balloon.

5. A balloon catheter characterized by, The balloon catheter comprises a balloon, an energy generator, a first axial fixing member, and a second axial fixing member; wherein the expanded state of the balloon comprises a first extended section, a lens section, and a second extended section; the lens section is disposed between the first and second extended sections along an axial direction; The energy generator is disposed in the hollow channel of the lens section, and the energy generator has a length corresponding to the lens section in the axial direction; The first axial fixing member is disposed in the hollow channel of the first extended section and is fixedly connected to a first end of the energy generator; the second axial fixing member is disposed in the hollow channel of the second extended section and is fixedly connected to a second end of the energy generator; The converging structure of the lens section is configured to converge energy generated by the energy generator to a target converging region.

6. The balloon catheter of claim 5, wherein, The converging structure comprises a first thickness section with a base thickness d1 and a second thickness section with a thickness d2; The thickness d2 of the second thickness section is an increase in phase difference thickness d on the base thickness d1; the phase difference thickness d is determined based on a phase difference between adjacent wave groups generated by the energy generator.

7. The balloon catheter of claim 6, wherein, The first and second thickness sections have different radial dimensions. The converging structure exhibits converging characteristics consistent with those of a quasi-Bessel lens.

8. The balloon catheter of claim 7, wherein, The intermediate length section of the lens section is determined based on the position of the target converging region. The converging structure exhibits converging characteristics consistent with those of a Bessel lens. The number of first and second thickness sections is n and n+1, respectively; n is determined based on the position of the target converging region.

9. The balloon catheter of claim 7, wherein, The converging structure comprises n first thickness sections and n+1 second thickness sections. When the distance between the center point of the position of the target converging region and the outer surface of the lens section in the radial direction is between [5.7mm, 6.3mm], n is 11. The converging structure exhibits converging characteristics consistent with those of a Fresnel lens.

10. The balloon catheter of claim 9, wherein, The lengths of the first, second, and intermediate length sections in the axial direction are determined based on the position of the target converging region according to the Fresnel zone plate formula. The converging structure exhibits converging characteristics consistent with those of a Fresnel lens.

11. The balloon catheter of claim 6, wherein, ​ ​ ​ 12. The balloon catheter of any one of claims 8 to 11, wherein, ​ The position of the target converging area is determined according to a target physiological position to be ablated.

13. The balloon catheter of claim 12, wherein, The target physiological position includes a sympathetic nerve position or a parasympathetic nerve position of a renal artery, a duodenum, a celiac artery, an abdominal aorta, a common hepatic artery, and a proper hepatic artery.

14. An ablation catheter characterized by, The ablation catheter comprises an energy generator, a first axial fixing member, a second axial fixing member, and a balloon having a first extended section, a lens section, and a second extended section in an expanded state; The lens section is arranged between the first and second extended sections, and the radial dimensions of the first and second extended sections increase in the axial direction towards the lens section and are connected to the lens section; The energy generator is arranged in a hollow channel of the lens section, the first axial fixing member is arranged in a hollow channel of the first extended section and fixedly connected to a first end of the energy generator, and the second axial fixing member is arranged in a hollow channel of the second extended section and fixedly connected to a second end of the energy generator; The length of the energy generator in the axial direction is equal to the length of the lens section in the axial direction; The converging structure of the lens section is configured to converge the energy generated by the energy generator to a target converging area.

15. A tubular ultrasound weak focusing device comprising a balloon, a transducer disposed within the balloon, the transducer emitting a sound beam for ablation, characterized in that, The sound beam adjusting structure is axially distributed along the balloon; The sound beam passing through the balloon and the sound beam adjusting structure forms an adjustable weak focusing area outside the balloon (1).

16. A tubular ultrasonic weak focusing device according to claim 15, wherein, The sound beam adjusting structure comprises at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are arranged on the balloon wall of the balloon (1).

17. A tubular ultrasonic weak focusing device according to claim 15, wherein The sound beam adjusting structure comprises at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are arranged on the outer wall of the transducer (2).

18. A tubular ultrasonic weak focusing device according to claim 15, wherein, The sound beam adjusting structure comprises at least one or more acoustic unit structures, and the at least one or more acoustic unit structures are arranged in the region between the transducer (2) and the balloon (2).

19. The tubular ultrasonic weak focusing device of claim 15, wherein, The acoustic unit structures are arranged in at least multiple groups in axial symmetry along the balloon (1), and the at least multiple groups of acoustic unit structures are arranged at both ends of the balloon (1).

20. A tubular ultrasonic weak focusing device according to claim 15, wherein, The acoustic unit structures comprise a first medium (41) and a second medium (42), and the first medium (41) and the second medium (42) are arranged in a spaced manner.

21. A tubular ultrasonic weak focusing device according to claim 20, wherein, The first medium (41) and the second medium (42) are adjacent in size.

22. A tubular ultrasonic weak focusing device according to claim 21, wherein, The first medium (41) is annular and arranged on the outer wall of the balloon (1) in an axial arrangement.

23. A tubular ultrasonic weak focusing device according to claim 22, wherein, The first medium (41) is made of the same material as the balloon (1).

24. A method of tubular ultrasonic weak focusing, characterized by The tubular ultrasonic weak focusing device according to any one of claims 15-23 is used to ablate a target treatment area.

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