CN106725838B

CN106725838B - Catheter with balloon dilation and radio frequency ablation functions and ablation method thereof

Info

Publication number: CN106725838B
Application number: CN201710077036.3A
Authority: CN
Inventors: 董永华; 沈美君
Original assignee: Shanghai Golden Leaf Medtech Co ltd
Current assignee: Shanghai Golden Leaf Medtech Co ltd
Priority date: 2016-02-11
Filing date: 2017-02-13
Publication date: 2024-03-29
Anticipated expiration: 2037-02-13
Also published as: CN106725838A

Abstract

The utility model discloses a catheter with balloon dilation and radio frequency ablation functions and an ablation method thereof. The radiofrequency ablation catheter is used for ablating hyperplastic tissues or nerves on a tube wall, and comprises: an expandable balloon positioned at the front end of the catheter, and an ablation component positioned on the outer wall or inside the balloon, wherein the ablation component ablates the proliferation tissue or nerve while the balloon expands gradually. The radio frequency ablation catheter combines the expansion effect of the expandable saccule and the ablation effect of the radio frequency ablation catheter, so that the ablation is performed while the expansion is performed.

Description

Catheter with balloon dilation and radio frequency ablation functions and ablation method thereof

Technical Field

The utility model relates to a catheter with balloon dilatation and radio frequency ablation functions, and also relates to an ablation method using the radio frequency ablation catheter, belonging to the technical field of interventional medical instruments.

Background

Interventional medical devices are an important branch of medical device industry developed in recent 10 years, and related interventional therapy is a brand-new technology which opens up a new chapter of medical science and technology. Interventional therapy is a diagnostic and therapeutic procedure performed by employing a series of interventional instruments and materials and modern digital diagnostic and therapeutic equipment. Compared with the traditional surgical operation, the interventional therapy is performed without operation, only local anesthesia is needed, and a small opening of 1-2 mm is cut, so that the surgical operation has the advantages of less bleeding, less wound, less complications, safety, reliability, quick postoperative recovery and the like, the pain born by a patient is greatly relieved, the operation difficulty of operators is reduced, the operation time and the hospitalization time are obviously shortened, and the cost is obviously reduced.

In the development process of interventional medical equipment industry, minimally invasive interventional therapy for treating cardiovascular and cerebrovascular diseases is one of the most representative technologies, and related interventional equipment industry is developed rapidly, mainly because cardiovascular and cerebrovascular diseases are main diseases of human beings, and the mortality and disability rate are high. The cardiovascular and cerebrovascular interventional instrument mainly comprises the following components: (1) cardiovascular interventional instruments: coronary drug eluting stent, PTCA balloon dilation catheter, guide catheter, radiography catheter, guide wire, etc.; (2) cerebral vascular interventional instruments: carotid stents, vertebral stents, intracranial vascular stents, microcatheters, liquid embolic materials, and the like; (3) peripheral vascular interventional instruments: a aortic stent graft, subclavian stent graft, renal stent graft, etc.; (4) electrophysiological interventional instruments: a radio frequency ablation catheter and a mapping catheter.

In the prior art, balloon dilation catheters are suitable for Percutaneous Transluminal Angioplasty (PTA) of the peripheral vascular system and for treating occlusive lesions of arteriovenous fistulae for autologous or artificial dialysis. Balloon dilation catheter is also suitable for post-dilation of balloon dilation stents or self-dilating stents in the peripheral vascular system. Through long-term experimental and clinical studies, applicant has further found that:

1. vascular stenosis

Although the balloon expansion treatment can effectively open the vascular lumen, restenosis often occurs, mainly because balloon expansion stimulates smooth muscle proliferation of local vascular wall, various methods are adopted at present to control vascular restenosis after balloon expansion, such as internal radiation, medicine balloons and the like, but no technology of interventional treatment on a narrow part by combining the expansion balloon and radio frequency ablation is adopted.

Clinical researches prove that on the basis of the conventional balloon dilation treatment of vasculitis, nerve ablation is carried out at the proximal end of a narrow part, so that the curative effect can be greatly improved, pain of a patient can be relieved after operation, long-surface vascular nerve ablation of a blood vessel can be maintained, the method has important value for improving long-term patency of the blood vessel, and is presumed to relieve or relieve the vascular tension (spasm) of the local blood vessel, but the existing method adopts balloon dilation first and then vascular ablation, and two steps, two parts and two sets of equipment are needed.

2. Lesion of lumen tumor

For example, bile duct cancer, esophagus cancer, intestinal cancer and the like, the conventional long needle-shaped ablation electrode needle is difficult to adapt to tubular lesions, restenosis can be quickly caused by hyperplasia of tumors by simple balloon dilation and stent treatment, the patency time of a lumen is improved by adopting an internal radiation and stent method in the prior art, but no equipment capable of simultaneously performing balloon dilation and tube wall tissue (tube wall nerve) ablation radio frequency ablation exists.

3. Spasmodic lesions

Such as achalasia of the cardiac artery, manifested as sustained contraction of the cardiac artery, has not been reported for treatment with a device combining balloon dilation with nerve ablation.

An endoluminal catheter for special treatment is disclosed in chinese utility model patent No. ZL 201220369156.3, comprising: the device comprises a radio-frequency electrode, a balloon, a catheter, a connecting tail wire and a control handle; the two ends of the balloon are communicated with the catheter, the catheter at one end of the balloon is connected with the control handle through the connecting tail wire to realize electrifying, and the radio-frequency electrode is combined on the wall of the balloon.

Although the endoluminal catheter provided by the utility model can ablate renal artery sympathetic nerves, the balloon dilatation degree cannot be controlled by palm in the operation process, and the electrodes can not be adhered to the wall or can not be adhered to the wall sufficiently due to the different tube diameters of different parts of the blood vessel caused by hyperplasia, so that the expected treatment effect cannot be achieved.

Disclosure of Invention

The utility model aims to provide a catheter with balloon dilatation and radio frequency ablation functions. The expanding action of the expandable saccule and the ablating action of the radio frequency ablating catheter are combined with each other, and the expanding and ablating can be achieved simultaneously, and the tube wall hyperplasia and the tube wall nerve ablating can also be achieved simultaneously.

Another technical problem to be solved by the present utility model is to provide an ablation method using the above-mentioned radio frequency ablation catheter.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

a radiofrequency ablation catheter for ablating proliferated tissue or nerves on a tube wall, comprising: an expandable balloon positioned at the front end of the catheter, and an ablation component positioned on the outer wall or inside the balloon, wherein the ablation component ablates the proliferation tissue or nerve while the balloon expands gradually. The radio frequency ablation catheter combines the expansion effect of the expandable saccule and the ablation effect of the radio frequency ablation catheter, so that the ablation is performed while the expansion is performed.

An ablation method using the radio frequency ablation catheter, wherein the catheter comprises a balloon and an ablation component arranged outside or inside the balloon, and the method comprises the following steps of:

delivering the balloon to a stenosed vessel;

pressurizing the balloon;

when the pressure reaches a preset value, the ablation part is conducted to perform ablation;

the predetermined value is capable of dilating the stenosed vessel.

The utility model uses the saccule to dilate the narrow lumen and ablates each layer of tissue on the local tube wall, thereby reducing or eliminating the probability of the re-occurrence of the narrow, relieving or eliminating the tension (spasm) of the local blood vessel or the lumen, and keeping the lumen unblocked for a long time. The radio frequency ablation catheter and the ablation method have obvious effects in the aspects of treating lumen stenosis and the like, can realize good effects of ablation and expansion, and reduce restenosis.

Drawings

FIG. 1 is a schematic representation of a first embodiment of a catheter of the present utility model having an expandable balloon coupled to an ablation electrode;

FIG. 2 is a schematic view of a second embodiment of a catheter of the present utility model having an expandable balloon coupled to a fixed stent;

FIG. 3 is a schematic view of a third embodiment of a catheter of the present utility model having an expandable balloon coupled to a detachable stent;

FIG. 4A is a schematic diagram showing an improvement of a third embodiment of the present utility model;

FIG. 4B is an enlarged view of a portion of the area L in FIG. 4A;

FIG. 5 is a constant pressure ablation flow chart of the present utility model;

FIG. 6 is a step-up ablation flow chart of the present utility model;

FIG. 7 is a schematic view of a fourth embodiment of a catheter employing a cutting ablation electrode in accordance with the present utility model;

FIG. 8 is a schematic cross-sectional view of the catheter of FIG. 7;

FIG. 9 is a schematic diagram of a fifth embodiment of a catheter of the present utility model with an inflatable balloon and an endoluminal ultrasound ablation nerve;

FIG. 10 is a schematic diagram showing an improvement of a fifth embodiment of the present utility model;

FIG. 11 is a schematic view of a cut-off balloon in various embodiments of the utility model;

FIG. 12 is a schematic view of a non-stop balloon structure in accordance with various embodiments of the present utility model;

fig. 13 is a schematic view of a non-stop balloon structure in various embodiments of the present utility model.

Detailed Description

The technical contents of the present utility model will be described in detail with reference to the accompanying drawings and specific examples.

The utility model combines the expansion effect of the expandable saccule and the ablation effect of the radio frequency ablation catheter to realize the expansion and the ablation at the same time, namely, the expansion of saccule stenosis and the ablation of the vessel wall (comprising the ablation of vascular smooth muscle cells and/or the ablation of adventitia sympathetic nerves) can be realized by using one catheter, and the hyperplasia of the vessel wall and the ablation of the vessel wall nerves can be realized at the same time. The utility model uses the saccule to dilate the narrow lumen and ablates each layer of tissue on the local tube wall, thereby reducing or eliminating the probability of the re-occurrence of the narrow, relieving or eliminating the tension (spasm) of the local blood vessel or the lumen, and keeping the lumen unblocked for a long time.

The ablation means in the present utility model means ablation by emitting energy, which is not limited to electric energy, ultrasonic waves, and the like.

The following detailed description refers to the accompanying drawings.

First embodiment

As shown in fig. 1, as a first embodiment of the present utility model, a catheter in which an expandable balloon is combined with a common coanda ablation electrode includes a catheter tip 1, a long tube 2, and a handle 4.

The handle 4 is provided with a pressure adjustment controller 3 (simply referred to as a pressure controller), a push-pull knob 41, and a wire drawing 5 (only the tail end of the wire drawing 5 is shown). The wire drawing 5 passes through the front end 1 of the catheter, the long tube 2 and the handle 4.

The catheter front end 1 includes a balloon 10 and one or more electrodes 20 attached to the outer periphery of the balloon 10. The catheter front end 1 further comprises a plurality of thermocouples 40. As an alternative, the catheter front end 1 may also comprise a plurality of pressure sensors 30. The pressure sensor is provided to visually understand the adhesion force of the electrode 20. The pressure sensor 30 may be omitted and the pressure controller 3 may be used to manually control the gas/liquid source.

Balloon 10 may be a constant pressure or pressurized balloon, as desired for operation. In this embodiment, the balloon 10 is a constant pressure control balloon. If the pressure sensor 30 detects that the adherence force does not reach a predetermined value (e.g., 6 atmospheres), performing a pressure increasing operation in a catheter controller automatic manner or an operator manual manner; if the adherence force reaches a preset value, performing stable pressure adjustment operation in an automatic mode of the catheter controller or in a manual mode of an operator; and if the adherence force is greater than a predetermined value, depressurizing. In this way, a constant pressure is achieved, thereby ensuring that the adherence force is stabilized within a predetermined range (e.g., 5-7 atmospheres) by the pressure regulation controller. The pressure value range, which is related to the balloon material characteristics and design parameters, can be set according to specific conditions. For example, compliant balloons are thin, with small pressure values; the non-compliant balloon is relatively thick and the pressure value may be large.

The diameter of balloon 10 is selected based on the maximum tube diameter of the target ablation zone, for example, a balloon having a diameter of 4mm is selected when ablation of a vessel having a tube diameter of no more than 4mm is desired. In general, balloon diameter refers to the expanded diameter at a nominal pressure (also referred to as a nominal pressure), and the expanded diameter at the maximum balloon pressure value (less than the burst pressure) is greater than or equal to the target tube diameter. In addition, the balloon is usually of a large size, and the space between the balloon and the balloon is usually 0.5 or 0.25mm. For example, if the pipe diameter is 3-6 mm, the catheter with the largest specification diameter, namely the balloon catheter with the diameter of 6mm, is selected, and the balloon catheters with different specifications are not required to be replaced frequently.

One or more electrodes 20 (ablation elements) are distributed on the balloon 10 at the catheter front end 1. Under operation of the pressure controller 3, the balloon 10 may be inflated and deflated. The balloon 10 is inflated to adhere the electrode 20, and the balloon is retracted into a sheath (not shown). Balloon 10 may be inflated by infusing a liquid, such as contrast media, cold saline, liquid nitrogen, or the like, or by inflating balloon 10 with a gas. The gas for infusion may be carbon dioxide or the like.

An electrode 20 located outside of the balloon 10 is used to perform radiofrequency ablation. The plurality of electrodes 20 are respectively disposed at the outer sides of the balloon 10 so that there is a good adhesion force between the electrodes 20 and the inner wall of the blood vessel. The electrodes 20 are each connected to a radio frequency source of the catheter.

The pressure sensors 30 may be distributed at any location on the balloon surface, most preferably in close proximity to the electrodes 20, for detecting the adhesion force of the electrodes 20. In an automatic manner, the pressure regulation controller 3 at the air/liquid source inlet is automatically turned on or off according to the adherence force of the pressure sensor 30, thereby automatically pressurizing (pressurizing) or not pressurizing (releasing) the balloon. In the manual mode, the magnitude of the adhesion force detected by the pressure sensor 30 is displayed, and the operator looks at the displayed value of the adhesion force to manually adjust the pressure adjustment controller 3 to achieve pressurization or depressurization of the balloon.

The catheter structure in the utility model can be realized: after the balloon is attached, the electrode is ablated; after the balloon is expanded again at the original position in the axial direction of the blood vessel, the electrode is ablated again; the electrode can be ablated after the balloon is attached to the wall, and the electrode is ablated again after the balloon moves axially in the blood vessel.

In the present embodiment, the pressure sensor 30 and the electrode 20 are disposed outside the balloon 10, respectively, in a superimposed manner. The pressure sensor is attached to the outer wall of the balloon 10 and the electrode 20 is positioned on the pressure sensor 30, i.e. the pressure sensor 30 is between the balloon 10 and the electrode 20. In this way, the electrode 20 protrudes outside the balloon 10, and the outer surface of the electrode 20 (the surface close to the vessel lumen wall) is spaced from the outside of the balloon 10 by a distance greater than the thickness of the electrode 20 itself. In this embodiment, the distance from the outer surface of the electrode 20 to the outside of the balloon 10 is equal to the thickness of the pressure sensor 30 plus the thickness of the electrode 20 itself. With this construction, the electrode 20 can penetrate deeper into the proliferating tissue like a breast nail, and the radiofrequency ablation effect is better, than a conventional electrode that is not provided with protrusions. Meanwhile, the electrode 20 penetrating into the proliferation tissue can be embedded into the proliferation tissue to a certain extent, so that the function of anchoring the balloon 10 is achieved, and the balloon 10 is prevented from sliding relative to the cavity wall in the pressurizing process. In addition, in the electrode ablation process, even if the surface of the proliferated tissue is uneven, the balloon or the electrode cannot move or slide, the contact area between the electrode and the tissue is increased, and the ablation effect and efficiency are improved.

Alternatively, the pressure sensor 30 may be located on the outer wall of the balloon 10, near the electrode 20, in a position juxtaposed to the electrode 20. The pressure sensor 30 is used to detect the magnitude of the electrode adhesion force. In this structure, the electrode 20 may be protruded outside the balloon 10 by increasing the thickness of the electrode 20 or the like, that is, the distance between the upper surface of the electrode 20 (the surface close to the lumen wall of the blood vessel) and the outside of the balloon 10 is greater than the thickness of the conventional electrode 20 itself (the conventional electrode thickness is about 0.05 mm) by between 0.05 mm and 2mm, and more preferably between 0.2 and 1 mm. The upper surface of the electrode may be a plane or an arc surface, a curved surface, etc., in which case the distance between the upper surface of the electrode and the outside of the balloon 10 means the distance between the highest point of the upper surface and the outside of the balloon 10.

In this embodiment, a plurality of thermocouples 40 are respectively provided on the outer wall of the balloon 10 at positions close to the electrodes. Alternatively, the thermocouple 40 may be disposed on the inner wall of the balloon 10 at a position near below the electrode 20 or near below the electrode 20 on the inner wall of the balloon 10.

The tip of the catheter tip 1, and also the tip developing head 50, is fixed by a tip connector 51 and is movable axially. The tail end of the developing head wire drawing 5 can be connected with a push-pull button 41 on the handle for further expansion and contraction, and can also be moved outside the handle 4 for directly feeding or drawing wires.

< second embodiment >

For brevity and effectiveness of description, only the portions of the present embodiment that differ from the first embodiment will be described herein.

As shown in fig. 2, in the present embodiment, the balloon 10 is externally provided with a fixing bracket 21. One end of the bracket 21 is fixed to the tip of the catheter and connected to a head end connector 51 (refer to fig. 1); the other end is exposed from the long tube. The fixed stent 21 may be collapsed but cannot be detached from the balloon, including but not limited to a basket stent.

The rack is in the figure a basket rack on which a plurality of electrodes 20 are arranged. After the stent 21 is expanded, the electrode 20 is partially or entirely buried in the tissue, increasing the electrode adhesion force and improving the ablation efficiency. The electrode 20 is disposed on the stent wire 211 of the stent 21, and such a structure makes the balloon of the present utility model applicable to a wide range. For example, a balloon with a diameter of 4mm may be used in a vessel with a diameter of less than 4mm, or in a vessel with a diameter of more than 4 mm. When used in vessels larger than 4mm, the electrode 20 is not yet attached even though the balloon 10 has reached the nominal pressure value, the stent may be expanded with an adjusting wire 101 (also called a connecting wire) to attach the electrode 20 on the stent 21 for effective ablation. Therefore, if the positions to be ablated are multiple in one operation and the pipe diameters are large in difference, the method can be used without frequently replacing large-sized catheters.

It will be appreciated by those of ordinary skill in the art that the electrodes 20 may also be disposed on the balloon 10, exposed from the interstices of the stent 21 (gaps between the stent wires 211), and out of contact with the stent wires 211. Because the basket type stent has larger gap, the electrode 20 is easy to be arranged so as not to interfere with the stent wire 211, and the mutual collision friction between the electrode on the balloon and the stent in the balloon expansion or stent expansion process is avoided. At this time, the electrode 20 is further protruded from the support wire 211 of the support 21 to be embedded into the smooth muscle proliferation tissue to a certain extent, so as to increase the adhesion force and enlarge the contact area with the proliferation tissue, thereby improving the ablation effect. In this embodiment, the distance from the upper surface of the electrode 20 to the outer surface of the balloon is greater than the distance from the upper surface of the stent wire 211 to the outer surface of the balloon, for example, the thickness of the electrode 20 itself is greater than the thickness of the stent wire 211.

The pressure sensor 30 may be disposed on the balloon 10 within the space of the stent 21 in the vicinity of the electrode 20 and out of contact with the stent wire 211. Of course, the pressure sensor 30 may be disposed below the electrode 20. In this case, the thickness of the electrode 20 itself may be smaller than or equal to the thickness of the support wire 211, and the sum of the thickness of the pressure sensor 30 and the thickness of the electrode 20 itself is larger than the thickness of the support wire 211.

< third embodiment >

Unlike the first and second embodiments, and referring to fig. 3 to 4, in the present embodiment, the outside of the balloon 10 is provided with a detachable stent 21 including a mesh stent, a flap stent, a spiral stent, or the like (hereinafter collectively referred to as a stent), or the like. The detachable stent 21 can be detached from the balloon 10 after being opened and left in the blood vessel. After the stent 21 is separated from the balloon 10, since the electrode 20 is still present on the balloon 10, the electrode 20 on the balloon 10 can still perform dilatation ablation on other vascular sites after the balloon 10 is moved to a position outside the stent 21, which is equivalent to a catheter without a stent (the first embodiment).

FIG. 3 shows the manner in which electrode 20 is disposed on balloon 10 with detachable stent 21; fig. 4A and 4B show the manner in which the electrode 20 is disposed on the outer surface of the balloon 10 and in contact with the stent 21. Unlike the second embodiment and fig. 2, the stent 21 is not connected to the catheter tip 51.

In fig. 4A and 4B, the electrode 20 is positioned on the outer surface of the balloon 10 in a location compatible with the configuration of the stent 21 such that the electrode 20 is in direct or indirect contact with the energy point 212 on the stent 21 (as shown in the enlarged view of fig. 4B). With such a configuration, the electrode 20 can deliver ablation energy to the energy points 212 (also referred to as energy emitting patches) on the stent 21, and ablation can be performed through the energy points 212 on the stent wire 211. Preferably, the energy points 212 are thickened protruding points on the stent such that the energy points 212 protrude more toward the proliferating tissue than other portions of the stent wire 211, thereby increasing the contact area and the adhesion force. The energy points (energy emitting sheets) provided on the stent wire 211 are conventional techniques and will not be described herein.

Alternatively, after the balloon 10 is inflated, the electrode 20 is exposed (but not in contact) from the interstices of the stent wire 211, and the electrode is thicker than the stent wire 211, so that the electrode 20 can be closer to the vessel wall than the stent 21. The position distribution of the electrode 20 fixed on the balloon 10 needs to be staggered with the stent, and various designs can be adopted, for example, the position of the electrode fixed on the balloon is far away from the stent wire 21 as possible by combining the balloon folding mode, the stent shape and the electrode distribution mode, so as to realize the mutual staggered position relationship of the electrode and the stent grid after the balloon is inflated.

The balloon 10 and the stent 21 are separable to allow the balloon 10 to retract the sheath, leaving the stent 21 in the vessel. The pressure sensor 30, the electrode 20 and the temperature sensor 41 provided on the balloon 10 may be stacked (up-down stacked) in the radial direction of the balloon 10, or may be arranged side by side.

When the balloon 10 is not expanded, the wire drawing can be pulled to expand the balloon 10, and the balloon 10 in the expansion process gradually promotes the expansion of the stent 21. The electrode 20 on the outer surface of the balloon 10 gradually adheres as the balloon 10 expands.

Since the stent 21 is designed in a cylindrical shape, the stent axial direction may be parallel to the blood vessel axial direction, so that the stent 21 first collides with the minimum diameter of the blood vessel, i.e., the site where smooth muscle hyperplasia is the greatest. At this time, the plurality of pressure sensors 30 distributed on the outer surface of the balloon 10 detect the adhesion force of the electrode 20, wherein one or more of the pressure sensors 30 detects a larger adhesion force (approaching a preset value) from a pressure sensor located closest to a site where smooth muscle hyperplasia is greatest, and the adhesion force detected by the other pressure sensors 30 is smaller and does not reach the preset value.

The electrodes 20 having the adhesion force reaching a predetermined value are ablated. Along with the ablation process, smooth muscle hyperplasia becomes thinner. At this time, the previously detected adherence force is the pressure sensor 30 of the preset value, and the detected adherence force at this time is decreased to be smaller than the preset value. The pressure of the balloon 10 may then be increased, either automatically or manually.

As the pressure of the balloon 10 increases, the balloon 10 expands the diameter of the stent 21. The mesh structure of the stent 21 can be clamped on smooth muscle proliferation tissue to avoid sliding of the smooth muscle proliferation tissue during the pressurizing process of the balloon 10. The electrode 20 is not contacted with the stent wire 211 and is exposed from between the stent wires 211, or the electrode 20 is contacted with the stent wire 211 and the energy points 212 protrude from other parts of the stent wire 211, the electrode or the energy points playing the role of ablation are embedded into the proliferation tissue or the vessel wall to a certain extent, thereby improving the adherence force and enlarging the contact area. Simultaneously, the balloon or the stent, or the combination of the balloon and the stent is used for dilating the blood vessel. Thereby achieving the effect of expanding the vessel wall while ablating.

Thus, the catheter of the present embodiment can be adapted to vessels having varying tube diameters, bringing about two advantages: one is that the same catheter can be applied to small blood vessels (for example, blood vessels with the diameter of 4 mm) and can be applied to coarse blood vessels (for example, blood vessels with the diameter of 12 mm); secondly, the vessel diameter of the same vessel is changed due to the proliferation of the vessel (for example, the vessel with the vessel diameter of 12mm is reduced to 6mm at a local position due to the proliferation), and the vessel can be ablated by using the same catheter.

The operation of the catheter is described below. This mode of operation applies to all embodiments.

When the catheter tip 1 is operated, the catheter tip 1 is placed at a stenosed site (a hyperplasia site) in a vascular target area, and the balloon 10 is inflated with a certain pressure (high pressure), so that the stenosed site is dilated, the balloon 10 can be dilated with a contrast medium or carbon dioxide, and the dilating effect is observed. The main practice is to use physiological saline to expand the saccule.

The balloon 10 expands under the named pressure, and dog bone phenomenon can occur due to the existence of hyperplasia, and the diameters of the proximal end and the distal end of the balloon 10 are larger than those of the stent 21. The impact of dog bone phenomena can be reduced with non-compliant or semi-compliant balloons. If the desired effect of balloon expansion is not achieved, the expansion pressure of balloon 10 is adjusted to the low pressure zone (less increase in balloon internal pressure caused by increasing the balloon diameter in the balloon low pressure zone compared to the high pressure zone) while electrode ablation is performed. The low pressure zone pressure is typically 0.1atm to 6atm (depending on the balloon material, wall thickness, diameter, etc.). The balloon 10 is adjusted to a low pressure area to perform ablation and expansion, so that the proliferation smooth muscle cells can be reduced, and the caliber (original proliferation section) of the ablation area is consistent with or close to the caliber of a target.

There are a number of ways in which the ablation process may occur. One commonly used is constant pressure ablation. The constant pressure value (in this case, the balloon pressure is required to expand a vessel narrowed by proliferation, usually 3 to 30atm, and is determined according to the diameter of the vessel narrowed, usually 4 to 6 atm), and then the catheter is automatically expanded while ablating. Specifically, parameters such as a constant pressure value, ablation time, temperature and the like are preset before ablation. Ablation is then performed according to the procedure of fig. 5.

As shown in fig. 5, the balloon inflation end begins to inflate balloon 10 (step 1). When the pressure reaches a predetermined value, the pressure is maintained (step 2), and the electrode 20 is conducted to perform ablation (step 3). In the case of maintaining a constant pressure value, since the preset constant pressure value is a pressure value that can dilate a stenosed vessel, it is relatively large, so that the balloon outer surface can be always kept in close contact with the vessel wall inner surface. Meanwhile, the electrode has larger thickness and can be deeper into the blood vessel wall, so that the energy of the electrode can enter into the proliferation tissue or the nerve tissue on the blood vessel wall more, and the ablation effect is improved.

The foregoing is the case when the pressurizing terminal is kept on, and the pressure sensor 30 is not required at this time. If the pressurizing end is closed after the pressurizing reaches a preset constant pressure value, the pressure of the balloon 10 may be maintained by means of the pressure sensor 30. Since ablation causes a decrease in muscle cell proliferation on the vessel wall, the vessel diameter becomes larger, and thus the adherence force decreases, the pressure sensor 30 on the balloon 10 senses that the adherence pressure decreases, and the pressure becomes smaller than a predetermined value (step 4), and thus the balloon 10 is continuously inflated (step 1 is returned).

When the pressure sensor 30 senses that the wall-attaching pressure reaches a predetermined value (step 2), the electrode 20 is conducted to perform ablation (step 3). When the ablation is completed, step 5 is entered to determine whether the ablation target is achieved. If the ablation target is achieved, that is, the muscle cell proliferation under the current preset pressure value is completely ablated, the diameter of the ablation area reaches or approaches to the diameter of the target tube. At this time, the vessel diameter is not increased any more, the pressure sensed by the pressure sensor 30 is maintained at a predetermined value, and ablation is ended; if not, ablation is again performed. When the balloon electrode is ablated again, the balloon electrode can be rotated for a certain angle and then ablated, the original angle can be maintained unchanged, but the balloon electrode is ablated after being advanced for a certain distance forwards and backwards in a blood vessel, and the balloon electrode can be ablated for a plurality of times at the same position until the balloon electrode is over.

The determination of whether ablation is complete may be in several ways. Generally, the total ablation time is set before ablation, and parameters such as the time t1 and the temperature are increased at intervals. In the total ablation time, performing ablation and expansion according to the steps; after the ablation is finished, whether the ablation reaches or approaches to the target pipe diameter or not is judged visually, and whether in-situ/shift ablation is needed or not.

For example, the hyperplasia is serious, the ablation time is set to be 1min, and after one ablation (ablation and expansion) is performed, the ablation can be performed continuously after a certain angle or a certain size is moved; until the diameter of the ablation zone reaches or approaches the target caliber.

Whether one ablation is ended or not can also be judged through the detected parameters such as impedance, temperature, power and the like.

After ablation, the balloon is contracted, and a contrast agent is injected to conduct renal artery radiography so as to observe the expansion effect and the blood flow smoothness. If the expansion and the ablation are unsatisfactory, the method can be repeated for 2 to 3 times.

The other is a step-by-step pressure ablation. The expansion pressure value can be gradually increased, and the ablation can be performed while the expansion pressure value is expanded. Before ablation, an initial pressure is setForce value M ₀ And maximum pressure value M _max And other parameters (total ablation time, interval boost ablation time t1 and temperature, etc.). The preset parameters may also include a pressure value, N, that is increased each time. It will be appreciated that the boost value N is a positive number, may be a fixed value, or may be any value that is preset, such as an arithmetic value that decreases stepwise from a larger value (e.g., N ₁ ＝2、N ₂ ＝1.5、N ₃ ＝1、N ₄ ＝0.5)

As shown in FIG. 6, the initial value M of the pressure is ₀ Inflation of balloon 10 begins (step 1). When the pressure sensor 30 senses that the pressure reaches the initial value M ₀ The electrode 20 is turned on for ablation (step 2). Next, it is determined whether the ablation time accumulation reaches the interval pressurizing ablation time t1 (step 3). At this time, the muscle cell proliferation has been partially ablated, and the vessel diameter is increased, so that the pressure sensed by the pressure sensor 30 is decreased.

If the interval pressurizing ablation time t1 is reached, step 4 is entered, the balloon 10 is pressurized at a larger, up-to-date pressure predetermined value M _n ＝M _n-1 +N(M _n ≤M _max ) Pressurizing and then judging the latest pressure preset value M _n Whether or not to reach maximum value M _max (step 5). If the maximum value M is reached _max It is determined whether an adjustment of the ablation position is required (step 66), such as rotating or moving the electrode back and forth. If the maximum value is not reached, returning to the step 2 to continue ablation.

In the step 3, if the interval pressurizing ablation time t1 is not reached, returning to the step 2, and continuing to ablate.

In step 5, if M _n Not reaching maximum M _max And returning to the step 2, and continuing the ablation.

If no position adjustment is required in step 6, for example, an ablation effect has been achieved, the balloon is contracted and ablation is ended. The ablation effect is achieved, namely that the muscle cell hyperplasia is completely ablated, and no further ablation is needed.

The M value is required to be set with an upper limit M _max Avoiding reaching the burst pressure value of the balloon, and setting the numerical value according to the parameters of the balloon such as the material, the wall thickness, the diameter and the likeTypically less than 20atm, for example 12atm or 14atm.

The balloon pressure value in the present utility model increases gradually. This is because ablation results in a smaller muscle cell proliferation and a larger vessel diameter, and a larger balloon pressure is required to adapt to the larger vessel diameter, thereby improving the adherence force and improving the ablation effect.

The position adjustment can be performed again by rotating the balloon electrode by a certain angle, or by maintaining the original angle but advancing a certain distance back and forth in the blood vessel, or by performing multiple ablations at the same position.

The electrode on the balloon can be one or more, 1 or more of the electrodes can emit radio frequency energy simultaneously or 1 or more of the electrodes can emit radio frequency energy, and the electrodes form a loop with the body surface; the multiple electrodes on the balloon can also be 1 of which is used as a negative electrode, and the other 1/multiple electrodes simultaneously or alternately emit radio frequency, and the negative electrode forms a loop.

Thus, in the present utility model, since the balloon operates in different pressure zones (low pressure zone and high pressure zone) with different expanded diameters, it is possible to adapt to vessels having varying tube diameters. Two advantages are brought about: one is that the same catheter can be applied to small blood vessels (for example, blood vessels with the diameter of 4 mm) and can be applied to coarse blood vessels (for example, blood vessels with the diameter of 12 mm); secondly, the vessel diameter of the same vessel is changed due to the proliferation of the vessel (for example, the vessel with the vessel diameter of 12mm is reduced to 6mm at a local position due to the proliferation), and the vessel can be ablated by using the same catheter.

In this embodiment, a plurality of temperature measuring devices (which may be thermocouples) may be distributed on the balloon 10, and may be located on the outer wall, the inner wall, or the middle layer of the multi-layer balloon 10, for detecting the temperature of the ablation point during the ablation process. Moreover, depending on the temperature detected by the temperature measuring device, safety control (the temperature is too high, ablation is automatically stopped), or pressure regulation (the temperature is too low, inflation increases balloon pressure (the maximum balloon pressure value must not be exceeded) or the stent is enlarged by regulating wire drawing to increase electrode wall-attaching pressure.

The material of the bracket 22 may be: metal materials, polymer materials, combinations of metal and polymer materials, and the like. The support 22 may be a unitary support or may be formed of multiple segments. The outer surface of the stent 22 is provided with 1 or more energy emission points (e.g., electrodes 20) whose conductivity can be combined to achieve multiple spot firing, cofiring.

The electrodes on the balloon 10 remain in active contact with the energy emitting points on the stent 22 and can deliver energy when the balloon 10 is in the initial collapsed state and expanded. In other words, initially the balloon and stent are in contact, and remain in contact when expanded; after ablation is completed, the balloon is contracted and the balloon and stent are separated. Alternatively, the rf point on the balloon 10 and the electrode on the stent 22 may be energy-transmitting for ablation.

When the balloon 10 is contracted, the stent 22 is separated from the balloon 10. Balloon 10 is inflated and stent 22 is inflated simultaneously. The following is a detailed description.

Case one: active expansion type bracket

An active expansion type stent, wherein the stent is actively expanded.

If the connecting wire 101 between the radio frequency point on the balloon and the electrode on the stent is shorter, the balloon is expanded and opened under the drive of the short connecting wire 101 or the buckle because of the thin wall of the balloon and the light weight, and the connecting wire keeps the state of connecting the radio frequency point and the electrode.

If the connecting wire 101 between the rf point on the balloon and the rf point on the stent is long, the connecting wire does not stretch the balloon when the stent is expanded, so the balloon is not opened. The balloon can be expanded after being pressurized, so that the stent is further expanded or the adherence force is improved.

After ablation, the connecting wire is disconnected when the catheter is retracted/rotated, and the balloon and the stent are separated. The saccule is contracted, the stent still keeps an expanded state, and the stent is reserved in the blood vessel.

The balloon is connected with the bracket, a silk thread 101 can be selected for connection, after entering the target position, the net tube is discharged from the sheath tube and automatically expands, and a radio frequency wire on the balloon is connected with an electrode on the bracket; the balloon is expanded, the wire 101 is still connected, and radio frequency energy can be effectively transmitted to the electrode on the bracket; after ablation is completed, the balloon is contracted, the angle is adjusted, the wire is pulled, the catheter is retracted or rotated because the stent is expanded and clung to the inside of the target vessel wall, the wire stress is increased, the position of an electrode connecting point on the connecting wire 101 and the stent is provided with a weak point (in a diameter thickness, a material and the like mode), the position is disconnected under the pulling force, and the stent and the balloon are separated.

As an alternative to connecting wires, a snap-fit connection between balloon and stent is also possible. The buckles ensure that the electrode on the bracket is effectively contacted with the radio frequency point on the saccule; after the active/passive expansion of the stent, the buckling points still effectively contact; after ablation is completed, the saccule is contracted, the buckling points are separated under stress, and then the saccule is separated from the bracket.

And a second case: passively expanding stent

The stent is of a passive expansion type, and is contacted initially, and the stent is pressed when the saccule is expanded, so that the stent is expanded synchronously. After ablation is completed, the stent remains in an expanded configuration, and remains in the vessel.

Before ablation, the stent is expanded, the stent cannot be expanded to the extent consistent with or close to the target pipe diameter due to proliferation, but is thinned due to the fact that the subsequent saccule is pressurized and ablated, the pipe diameter is enlarged, and the stent can be further expanded.

The balloon is pressurized according to preset low pressure, and then is pressurized while ablation. Ablation may also be performed by setting directly to the nominal pressure value.

The energy for ablation is delivered to the electrode 20 on the balloon 10, then to the stent 22, and then to the vessel wall via the emitted energy points provided on the outer surface of the stent 22, thereby ablating the target area.

The balloon 10 is deflated, the balloon 10 is sucked under negative pressure to minimize the diameter of the balloon 10, and when the balloon 10 is deflated, the stent 22 is detached from the balloon 10 and left in the lumen of the target.

As described above, the expansion may be synchronized or sequenced. The stent cannot be folded after being expanded, but the connecting wire/connecting point or the connecting buckle is stressed to be disconnected or separated, so that the balloon can be folded.

If the stent is an active expansion type stent, the stent is actively expanded, and the balloon is opened under the drive of a short connecting wire or a buckle due to the thin wall of the balloon and light weight; if the connecting wire between the radio frequency point on the balloon and the radio frequency point on the stent is longer, the balloon will not be opened when the stent expands, although the electrode on the stent and the radio frequency point on the balloon are still connected by the long connecting wire; the saccule is pressurized and expanded, so that the stent is further expanded or the adherence force is improved; after ablation, the balloon is contracted, the stent is still in an expanded state, and when the catheter is retracted/rotated, the connecting wires are disconnected, and the balloon and the stent are separated.

If the stent is of a passive expansion type, the stent is contacted initially, the stent is synchronously expanded when the balloon is expanded, and the stent is kept in an expanded form after ablation is completed; before ablation, the stent is expanded, the stent cannot be expanded to the extent consistent with or close to the target pipe diameter due to proliferation, but is further expanded due to the fact that the proliferation is thinned by pressurizing and ablation of a subsequent saccule; the balloon is pressurized according to preset low pressure, and then is pressurized while being ablated, or is directly set to a nominal pressure value for ablation.

< fourth embodiment >

Fig. 7 and 8 are schematic structural views of a catheter with an expandable balloon coupled to a cutting ablation electrode in accordance with a fourth embodiment of the present utility model.

In this embodiment, the radiofrequency ablation catheter 1 with an expandable balloon is provided, the front end of the catheter 1 is provided with a balloon 10, and one or more cutting devices (cutting blades) 23 are longitudinally distributed on the balloon 10. The cutting blade 23 is also an ablation electrode and can ablate at the same time as cutting. The cutting blades 23 of a cutting device may be integral or may be formed of multiple cutting blades (conductive or nonconductive with respect to each other). In the case of ablation, the cutting blades 23 on a plurality of cutting devices may be ablated simultaneously, or may be ablated separately or in combination of several cutting blades.

The balloon is distributed with a plurality of temperature measuring devices, which can be positioned on the outer wall and the inner wall of the balloon or in the middle layer of the multi-layer balloon.

A cutting blade 23 is longitudinally installed at the outer surface of the balloon 10. The cutting blade 23 may cut the lesion when the balloon 10 is inflated. Thus, when the balloon 10 is expanded, the cutting blade 23 pre-installed on the balloon 10 can cut a clean incision at the lesion. Since the cutting blade 23 is also an ablation electrode at the same time, ablation can be performed at the same time as cutting. Along with the ablation, the adherence force is reduced, the pressure sensor feeds back to the controller, and the controller controls the pressurization of the balloon, so that the expansion is realized while the ablation is performed.

When the balloon is inflated, the pressure of the balloon 10 slowly rises as the balloon 10 expands, because of the ablation of the cutting blade 23, allowing the balloon 10 to expand stepwise to increase the adhesion force. In expanding the balloon 10, over pressurization is avoided, preventing the cutting blade 23 from remaining in the lumen when the balloon 10 is ruptured.

< fifth embodiment >

In the experiments of vascular ablation, the applicant finds that, by applying a certain radio frequency ablation dose to the local vascular wall, sympathetic nerve fibrosis on the adventitia of the blood vessel can be purposefully caused, the thickness of the wall of the local vascular wall can be reduced, the number of smooth muscle cells on the vascular wall can be reduced, and meanwhile, the integrity of the vascular wall can be maintained. Therefore, a means of combining balloon dilation with vessel wall nerve ablation has been proposed.

Fig. 9 and 10 are schematic views of a catheter structure incorporating an expandable balloon and an endoluminal ultrasound device according to a fifth embodiment of the present utility model. Fig. 9 is a schematic structural view of ablation of a tube wall (ultrasonic focusing on the tube wall), and fig. 10 is a schematic structural view of ablation of a nerve (ultrasonic focusing on an adventitia layer).

In this embodiment, the balloon 10 at the front end of the catheter 1 is provided with 1 or more electrodes 20 (the electrodes may be optional or not) on the outer surface of the balloon 10, and an ultrasound emitting device 80 (ablation member) is provided inside the balloon 10. The ultrasonic transmitting device 80 can release ultrasonic waves to focus on the pipe wall to realize the ultrasonic pipe wall (smooth muscle hyperplasia ablation) in the cavity; the ultrasound emitting device 80 may also release ultrasound focused to the adventitia layer for nerve ablation (nerve tissue ablation).

When the balloon 10 is inflated, the ultrasound transmitting device 80 transmits ultrasound waves, which are focused to a target ablation site for ultrasound tube wall ablation or nerve ablation. The balloon 10 is further expanded during the ablation process, and the ablation can be performed while expanding. When the ultrasonic tube wall is ablated, the wall attaching force of the balloon 10 is reduced due to the ablation of a part of the muscle cell hyperplasia, the pressure sensor 30 senses the change, and the pressurizing of the balloon 10 is triggered to keep the wall attaching force.

In addition, fig. 11-13 show different types of schematic views of the inflatable balloon of the present utility model. These types are various design examples that, when expanded, may maintain the passage of a portion of blood flow, respectively. Can be in the form of a blood vessel blockage after expansion, such as a cylinder, a round drum, a sphere and the like; or can be in a form of maintaining vascular circulation.

For example, the expandable balloon may be cylindrical, drum-shaped, or spherical after being expanded, or may have a hexagonal quincuncial shape, a pentagram shape, or the like. The cylinder, drum, sphere, and then for maintaining partial blood flow may be, but not limited to, quincuncial, pentagram, etc. The electrodes are distributed at the peak positions of the sacculus, and the sticking of the electrodes can be realized after the sacculus is expanded; and blood in the blood vessel of the target area can still circulate after the balloon is expanded.

In treating vascular stenosis, the balloon of the present utility model is expanded to treat the stenosis while the ablation electrode on the balloon ablates the tissue of the vessel wall, including smooth muscle on the wall and/or sympathetic nerves on the adventitia, to perform several functions: reducing the thickness of smooth muscle, reducing or preventing vasospasm, dilating blood vessel, and preventing restenosis. It is understood that the radio frequency ablation electrode outside the balloon and the ultrasonic electrode inside the balloon are arranged simultaneously, so that the muscle cells with hyperplasia on the tube wall and the nerves on the tube wall can be ablated simultaneously.

The balloon on the catheter can overcome the occurrence of dog bone phenomenon through stent expansion even if adopting a compliant balloon.

The ablation electrodes on the balloon release ablation energy in different doses according to the lesion degree of the local tube wall, and the optimal mode is a bipolar or multipolar ablation mode.

Different doses of ablated smooth muscle tissue may be selected as desired: thinning, preventing restenosis, or not ablating smooth muscle tissue, only ablating sympathetic nerves on the adventitia.

The catheter with both balloon dilatation and radiofrequency ablation functions and the ablation method thereof provided by the utility model are described in detail above, but it is obvious that the specific implementation form of the utility model is not limited thereto. Various obvious modifications thereof will be apparent to those skilled in the art without departing from the spirit of the utility model and the scope of the claims.

Claims

1. A radiofrequency ablation catheter, comprising:

an expandable balloon at the forward end of the catheter;

an ablation member located outside the balloon;

after the balloon is attached, the ablation component is ablated;

the catheter further comprises a bracket arranged outside the balloon; wherein the stent is an active expansion type stent, the ablation component refers to an energy emission point which is arranged on the stent and used for ablation, the energy emission point is an electrode,

the catheter further comprises an electrode disposed on an outer surface of the balloon,

the electrode of the bracket is connected with the electrode of the saccule,

when the connecting wire between the electrode on the balloon and the electrode on the bracket is short, the balloon is expanded and opened under the drive of the connecting wire, and the connecting wire keeps the state of connecting the electrode; when the connecting wire between the electrode on the balloon and the electrode on the stent is long, the connecting wire can not stretch the balloon when the stent is expanded, so that the balloon is not opened; the balloon can be expanded after being pressurized, so that the stent is further expanded or the adherence force is improved,

the catheter increases balloon pressure by inflation or stent expansion by a connecting wire to increase the ablation member wall pressure, and the connecting wire allows separation of the balloon and stent after ablation is completed.

2. The radiofrequency ablation catheter of claim 1, wherein:

the ablation member is an electrode on an outer surface of the balloon, and an upper electrode surface of the outer surface of the balloon is spaced from the outer surface of the balloon by a distance greater than a thickness of the electrode.

3. The radiofrequency ablation catheter of claim 1, wherein:

the ablation part is an electrode on the outer surface of the balloon, and the thickness of the electrode on the outer surface of the balloon is more than 0.05 mm and less than or equal to 2 mm.

4. The radiofrequency ablation catheter of claim 1, wherein: the stent includes a plurality of stent filaments.

5. The radiofrequency ablation catheter of claim 1, wherein:

the support is a separable support; after the balloon is separated from the stent, the ablation member is ablated again.

6. The radiofrequency ablation catheter of claim 1, wherein: the connecting wire is provided with a breaking point for breaking under stress, thereby separating the stent from the balloon.