Ablation catheter

Abstract

The ablation catheter comprises a double-helix structure, a bendable section, a catheter body and a control handle which are sequentially connected from the far end to the near end. The double-spiral structure comprises a main spiral section and an auxiliary spiral section; the main spiral sections and the auxiliary spiral sections are distributed around the same axis in a staggered mode in the same direction. The far end of the auxiliary spiral section is connected with the far end of the main spiral section through a spiral section fixing piece, or the far end of the auxiliary spiral section is provided with the spiral section fixing piece, and the spiral section fixing piece is movably connected with the main spiral section; a plurality of electrodes are arranged on the main spiral section; a wire guide cavity and a wire guide cavity which are separately arranged are formed in the main spiral section; a shaping wire cavity is formed in the auxiliary spiral section; and shaping wires are arranged in the shaping wire cavities. By means of the configuration, under the condition that the spiral section is kept soft and not prone to damaging tissue, the supporting performance of the electrode area is enhanced, the effective attaching performance is improved, and meanwhile the treatment covering area is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, and particularly relates to an ablation catheter with a double-helix structure at a distal end. BACKGROUND

[0002] Renal denervation (RDN) is a new interventional surgery for treating refractory hypertension. In recent years, with the in-depth study of the role of the renal sympathetic nervous system in the pathogenesis of hypertension, RDN has been widely concerned as a treatment method. Common indications for renal denervation include refractory hypertension, heart failure, etc. The results of the published clinical trials all show that RDN treatment of hypertension is safe and effective, and its efficacy and blood pressure lowering characteristics are independent of the accompanying antihypertensive drugs, and can be used as an adjunctive treatment for drug antihypertensive therapy.

[0003] Refractory hypertension refers to a type of hypertension that is not controlled by three or more antihypertensive drugs, including one diuretic. In patients with refractory hypertension, patients who are not tolerant to conventional drugs often show a greater blood pressure lowering effect than when taking drugs alone. In addition, the Symplicity HTN-1 and HTN-2 trials also showed that RDN has potential benefits for the relief of symptoms and improvement of quality of life in patients with heart failure, chronic kidney disease, etc. The RDN procedure is usually to ablate the sympathetic nerves around the renal artery by radiofrequency energy or ultrasonic energy, destroy these nerve fibers, and reduce the activity of the sympathetic nerves, thereby achieving the effect of lowering blood pressure. RDN is performed by inserting a catheter through the femoral artery or radial artery, and the catheter reaches the opening of the renal artery through the aorta. After the catheter is in place, radiofrequency energy or ultrasonic energy is used to ablate the sympathetic nerves around the renal artery. During the procedure, the catheter handle can be moved and rotated to bring the distal treatment segment of the catheter to the target position, and then ablate each renal artery multiple times (such as 4-6 times), with each ablation lasting about 1-2 minutes.

[0004] However, the traditional spiral ablation catheter is provided with multiple electrodes along the distal spiral segment tube body, and is straightened and bent back by cooperating with a guide wire. When the spiral ablation catheter is used in surgery, due to the self-adaptability of the spiral segment tube body, when the guide wire is withdrawn from the spiral segment, the spiral segment presents an elongated spiral shape in the blood vessel, and in this case, the spacing of the electrodes in the circumferential direction of the blood vessel is elongated. Thus, when the spiral segment enters a blood vessel with a smaller diameter, the spiral segment even presents a linear state, and in this case, the non-treatment area between the stimulation point and the ablation point is increased, and the treatment efficiency is obviously reduced without operating the position of the catheter, and if the catheter is frequently twisted and operated, the operation time is prolonged, and especially in the case of a slender tube body, the twisting and operating difficulty is relatively large. When the catheter is used to treat a blood vessel with a large diameter, the adhesion of the spiral segment to the inner wall of the blood vessel cannot be guaranteed, and there is a risk that the ablation and mapping depth is low and the treatment effect is not complete.

[0005] It should be noted that the information disclosed in the background section of the present application is intended to deepen the understanding of the general background of the present application, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art. Content of the utility model

[0006] The purpose of the present application is to provide an ablation catheter to solve the problems that the ablation catheter cannot well adhere to the blood vessel wall and needs to be twisted and operated to find the target point in the prior art.

[0007] To achieve the above-mentioned purpose, the present application provides an ablation catheter, which comprises a double-spiral structure, a bendable segment, a catheter main body and a control handle connected in sequence from the distal end to the proximal end.

[0008] The double-spiral structure comprises a main spiral segment and an auxiliary spiral segment; the main spiral segment and the auxiliary spiral segment are distributed in the same direction around the same axis.

[0009] The distal end of the auxiliary spiral segment and the distal end of the main spiral segment are connected by a spiral segment fixing piece, or the distal end of the auxiliary spiral segment is provided with a spiral segment fixing piece, and the spiral segment fixing piece is movably connected with the main spiral segment.

[0010] Multiple electrodes are arranged on the main spiral segment; a guide wire cavity and a first lead wire cavity are arranged separately in the main spiral segment; a shaping wire cavity is arranged in the auxiliary spiral segment; a shaping wire is arranged in the shaping wire cavity.

[0011] Optionally, at least one electrode is arranged on the auxiliary spiral segment, and a lead wire cavity is further arranged in the auxiliary spiral segment separately from the shaping wire cavity; the projections of the electrodes on the main spiral segment and the electrodes on the auxiliary spiral segment on the same projection plane are distributed in the circumferential direction.

[0012] Optionally, the number of electrodes on the main helical segment is 2-8, and the number of electrodes on the auxiliary helical segment is no more than 4.

[0013] Optionally, the interior of at least one of the main helical segment and the auxiliary helical segment is further provided with an independent perfusion channel, and the surface of some of the electrodes is provided with a perfusion through-hole in communication with the perfusion channel.

[0014] Optionally, the diameter of the main helical segment is the same as the diameter of the auxiliary helical segment, the pitch of the main helical segment is the same as the pitch of the auxiliary helical segment, and the helical starting point of the main helical segment is different from the helical starting point of the auxiliary helical segment by half a pitch.

[0015] Optionally, the total length of the main helical segment is greater than or equal to the total length of the auxiliary helical segment, and / or the elasticity of the auxiliary helical segment is less than the elasticity of the main helical segment.

[0016] Optionally, the distal end of the auxiliary helical segment is provided with a linear segment.

[0017] Optionally, the auxiliary helical segment is further provided with a sensor cavity, which is shared with or separately provided from the shaping wire cavity; at least one sensor is arranged in the sensor cavity.

[0018] Optionally, the sensor is a magnetic positioning sensor or a pressure sensor, and at least one of the magnetic positioning sensor and the pressure sensor is arranged in the sensor cavity, and the sensor is arranged at at least one of the proximal end, the distal end, and the middle position of the auxiliary helical segment in the sensor cavity.

[0019] Optionally, at least two magnetic positioning sensors are arranged in the sensor cavity, and the distance between the two farthest magnetic positioning sensors covers at least the entire helical region of the auxiliary helical segment.

[0020] Optionally, 1-3 sensors are arranged in the sensor cavity along the helical region of the auxiliary helical segment.

[0021] Optionally, when the helical segment fixing member is movably connected to the main helical segment, the helical segment fixing member is sleeved on the outside of the main helical segment, the distal end of the main helical segment is provided with a distal end limiting structure for blocking the helical segment fixing member at the distal end of the helical segment fixing member.

[0022] Optionally, the helical segment fixing member is fixed to the distal end of the shaping wire, and / or the distal end limiting structure is a molten ball or a glue ball.

[0023] Optionally, the proximal end limiting structure is arranged at the proximal end of the second electrode or the fourth electrode counted from the distal end of the main helical segment; and / or the distance from the proximal end limiting structure to the helical starting point of the main helical segment is greater than the total length of the helical segment of the auxiliary helical segment.

[0024] Optionally, the proximal end limiting structure is arranged at the proximal end of the second electrode or the fourth electrode counted from the distal end of the main helical segment; and / or the distance from the proximal end limiting structure to the helical starting point of the main helical segment is greater than the total length of the helical segment of the auxiliary helical segment.

[0025] Optionally, the ablation catheter further comprises a guide wire, which sequentially passes through the guide wire channel of the catheter body, the guide wire lumen of the bendable segment, and the guide wire lumen of the double helix structure, and the proximal end of the guide wire is connected to the control handle.

[0026] The ablation catheter provided above comprises, in sequence from the distal end to the proximal end, a double helix structure, a bendable segment, a catheter body, and a control handle; the double helix structure comprises a main helical segment and an auxiliary helical segment; the main helical segment and the auxiliary helical segment are distributed in the same direction around the same axis; the distal end of the auxiliary helical segment and the distal end of the main helical segment are connected by a helical segment fixing member, or the distal end of the auxiliary helical segment is provided with a helical segment fixing member, and the helical segment fixing member is movably connected to the main helical segment; a plurality of electrodes are arranged on the main helical segment; a guide wire lumen and a guide wire lumen are arranged separately in the main helical segment; a shaping wire lumen is arranged in the auxiliary helical segment; and a shaping wire is arranged in the shaping wire lumen.

[0027] In this way, the two helical segments can complement each other in spatial position while maintaining softness and not easily damaging tissues, so that the circumferential treatment along the blood vessel can be achieved without twisting during the operation, thereby reducing the difficulty of finding the target point, improving the coverage rate of the treatment area, shortening the operation time, and improving the operation efficiency; on the other hand, the shaping wire in the auxiliary helical segment provides additional support, thereby improving the mapping and ablation efficiency; on the other hand, when the two helical segments are connected by the helical segment fixing member, the double helix can be straightened or the single helix can be straightened, and the single helix straightening can make the main helical segment reach the blood vessel branch that the double helix structure cannot enter, thereby increasing the treatment range. BRIEF DESCRIPTION OF DRAWINGS

[0028] Those skilled in the art will understand that the provided drawings are for a better understanding of the present application and do not constitute any limitation on the scope of the present application.

[0029] Figure 1 is the overall schematic diagram of the ablation catheter of the embodiment of the present application, in which a dashed line box is arranged to highlight the control handle.

[0030] Figure 2 is a side view structural schematic diagram of the main helical segment of the embodiment of the present application.

[0031] Figure 3 is a front view structural schematic diagram of the main helical segment of the embodiment of the present application.

[0032] Figure 4 is a side view structural schematic diagram of the auxiliary helical segment of the embodiment of the present application.

[0033] Figure 5 is a front view structural schematic diagram of the auxiliary helical segment of the embodiment of the present application.

[0034] Figure 6 is a distal end cross-sectional schematic diagram of the double helix structure of the embodiment of the present application.

[0035] Figure 7 is a front view structural schematic diagram of the double helix structure of the embodiment of the present application.

[0036] Figure 8 is a front view structural schematic diagram of the double helix structure provided with a sensor cavity of the embodiment of the present application.

[0037] Figure 9 is a structural schematic diagram of the external sensor provided for the shaped wire of the embodiment of the present application.

[0038] Figure 10 is a structural schematic diagram of the helical segment fixing member movably connecting two helical segments of the embodiment of the present application.

[0039] Figure 11 is a structural schematic diagram of the bendable segment of the embodiment of the present application.

[0040] Figure 12 is a distal end schematic diagram of the pull wire of the embodiment of the present application.

[0041] Figure 13 is a schematic diagram of the distal end of the pull wire fixed to the shaped wire fixing member of the embodiment of the present application.

[0042] Figure 14 is a schematic diagram of the distal end of the pull wire provided with a pull wire fixing member of the embodiment of the present application.

[0043] In the drawings:

[0044] 1 - double helix structure; 101 - main helix segment; 10101 - guide wire lumen of double helix structure; 10102 - guide wire lumen of main helix segment; 10103 - proximal limit structure; 10104 - distal limit structure; 102 - auxiliary helix segment; 10201 - style wire lumen; 10202 - style wire; 10203 - guide wire lumen of auxiliary helix segment; 10204 - style wire fixing member; 10205 - linear segment; 10206 - sensor lumen; 10207 - sensor; 103 - helix segment fixing member; 104 - electrode; 10401 - perfusion through hole; 105 - perfusion channel; 204 - pull wire; 20401 - pull wire fixing member; 2 - bendable segment; 201 - helix butt joint segment; 202 - multi-lumen tube of bendable segment; 20201 - guide wire lumen of bendable segment; 20202 - pull wire lumen; 20203 - guide wire lumen of bendable segment; 3 - catheter main body; 301 - straightener; 4 - control handle. DETAILED DESCRIPTION

[0045] In order to make the purposes, advantages and features of the present application clearer, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be noted that the drawings are all very simplified and not drawn in proportion, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present application. In addition, the structures shown in the drawings are often part of the actual structures. In particular, the emphasis shown in each drawing is different, and sometimes different proportions are used.

[0046] As used in this application, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise. The term "and / or" means "and" or "or," i.e., "and / or" will be interpreted to mean one or all of words it connects. The term "at least two" is generally employed in its sense including "two or more" unless the context clearly dictates otherwise. The terms "first," "second," and the like, are used merely as labels to aid description and do not necessarily indicate relative importance or a quantity by which they are described. Thus, a feature described as "first," "second," etc. can implicitly or explicitly include one or both of the features, and "one" or "the" feature can implicitly or explicitly include one or more of the features. "One end" and "the other end," as well as "proximal" and "distal," generally refer to two portions that correspond to each other, and include end points. The terms "proximal" and "distal" are defined herein with respect to an ablation catheter having one end for intruding into a human body (a needle tip end) and a handle end that extends out of the body. The term "proximal" refers to a position closer to the handle end of the ablation catheter, and the term "distal" refers to a position closer to the end of the ablation catheter for intruding into the human body and thus further away from the handle end of the ablation catheter. Alternatively, in a manual or hand-operated application, the terms "proximal" and "distal" are defined herein with respect to an operator such as a surgeon or clinician. The term "proximal" refers to a position closer to the operator, and the term "distal" refers to a position closer to a patient's affected area and thus further away from the operator. Furthermore, as used in this application, "mounted," "connected," "linked," one element "disposed" on another element should be broadly understood, generally only indicating that there is a connection, coupling, cooperation or transmission relationship between two elements, and the two elements can be directly or indirectly connected, coupled, cooperated or transmitted through intermediate elements, and cannot be understood as indicating or implying the spatial positional relationship between the two elements, i.e. one element can be in any position inside, outside, above, below or one side of another element, unless the context clearly indicates otherwise. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used with respect to the exemplary embodiments as they are shown in the drawings, upward or upward direction is toward the top of the corresponding drawing, and downward or downward direction is toward the bottom of the corresponding drawing.

[0047] The purpose of the present application is to provide an ablation catheter to solve the problem that the ablation catheter distal electrode region cannot well adhere to the blood vessel wall and needs to be twisted to operate the catheter to find the target. The following will be described in conjunction with the accompanying drawings.

[0048] To achieve the above-mentioned purpose, please refer to Figures 1 to 14The embodiment of the present application provides an ablation catheter, which comprises a double helix structure 1, a bendable section 2, a catheter main body 3 and a control handle 4 connected in sequence from the distal end to the proximal end. Specifically, the double helix structure 1 is arranged at the distal end of the bendable section 2, the proximal end of the bendable section 2 is connected with the distal end of the catheter main body 3, and the proximal end of the catheter main body 3 is connected with the control handle 4.

[0049] Optionally, the ablation catheter of the embodiment further comprises a straightener 301, which is coaxially arranged with the catheter main body 3; the inner diameter of the straightener 301 is matched with the outer diameter of the catheter main body 3, so that the straightener 301 can be sleeved outside the catheter main body 3 and can slide along the catheter main body 3. Before the operation, the straightener 301 can assist the catheter to pass through the sheath tube after the double helix structure 1 is straightened, and the sheath tube is, for example, a guide sheath, a guide catheter, a guide device, a puncture sheath and various commonly used sheath tubes.

[0050] The double helix structure 1 specifically comprises a main helix section 101 and an auxiliary helix section 102. The main helix section 101 undertakes the main treatment function in the operation, and the auxiliary helix section 102 plays the main additional support function in the operation. The main helix section 101 and the auxiliary helix section 102 are arranged in the same direction around the same axis. That is, the main helix section 101 and the auxiliary helix section 102 are coaxial and arranged in the same direction, aiming to not increase the outer diameter of the electrode region at the distal end of the ablation catheter.

[0051] The diameter of the main helix section 101 and the diameter of the auxiliary helix section 102 are preferably the same, that is, the maximum diameter of the double helix structure 1 is not greater than the maximum diameter of a single helix section, so that even if the double helix is arranged, the outer diameter of the electrode region at the distal end of the catheter will not be increased. The maximum diameter of the double helix structure 1 can be adjusted and changed according to the use scene. Optionally, the maximum diameter of the double helix structure 1 is 3mm-8mm, which can be suitable for the blood vessel diameter of most patients, and the maximum diameter of the double helix structure 1 is the maximum diameter of the main helix section 101 and the auxiliary helix section 102 after bending recovery.

[0052] In order to arrange the two helix structures in the same direction in a staggered manner, in the specific implementation, the helix starting points of the main helix section 101 and the auxiliary helix section 102 at the proximal end can be arranged to be different by at least half a pitch. For example, Figure 1 In the specific embodiment described in the specification, the helix starting point of the main helix section 101 at the proximal end and the helix starting point of the auxiliary helix section 102 at the proximal end are different by half a pitch d, which is the most preferred. In order to enable the main helix section 101 to carry more electrodes 104, preferably, the main helix section 101 starts to extend in the helix at the proximal end first, and the number of helixes is more than that of the auxiliary helix section 102. Preferably, the pitch of the main helix section 101 and the pitch of the auxiliary helix section 102 are the same.

[0053] In addition, the main helical segment 101 and the auxiliary helical segment 102 need to be connected together, and there are two connection modes.

[0054] With reference to the drawings Figure 7 and Figure 8 The first connection mode is that the distal end of the main helical segment 101 and the distal end of the auxiliary helical segment 102 are connected through the helical segment fixing member 103, so that the main helical segment 101 and the auxiliary helical segment 102 can remain relatively static. In this way, the two helical segments can be straightened or bent simultaneously. When the two helical segments are straightened, the diameter of the double helical structure 1 after being straightened will be smaller, which is easy to enter the blood vessel, and will not generate additional force on the blood vessel with a larger diameter.

[0055] Specifically, when the guide wire passes through the main helical segment 101, the helical structure of the main helical segment 101 is stretched and straightened in an approximately linear shape under the force provided by the guide wire in the axial direction of the catheter, and the auxiliary helical segment 102 is also stretched and straightened at the same time due to the coaxial connection with the main helical segment 101. The main helical segment 101 and the auxiliary helical segment 102 after being straightened can present an approximately linear twisted shape. Conversely, when the guide wire is withdrawn from the main helical segment 101, the main helical segment 101 and the auxiliary helical segment 102 can simultaneously bend and recover to a helical state.

[0056] With reference to the drawings Figure 10 The second connection mode is that the distal end of the auxiliary helical segment 102 is provided with a helical segment fixing member 103, and the helical segment fixing member 103 is movably connected with the main helical segment 101, so that the main helical segment 101 and the auxiliary helical segment 102 can remain relatively movable, thereby realizing the separate straightening or bending of the main helical segment 101. When the main helical segment 101 is straightened alone, it can reach the branch blood vessels that the double helical structure 1 cannot enter, thereby increasing the range of surgical treatment.

[0057] Specifically, when the guide wire passes through the main helical segment 101, only the main helical segment 101 is straightened, and the auxiliary helical segment 102 can remain in a helical state without being straightened due to the movable helical segment fixing member 103 on the main helical segment 101. Further, when the guide wire is withdrawn from the main helical segment 101, only the main helical segment 101 is bent and recovered to a helical state.

[0058] It should be understood that the helical segment fixing member 103 will not be detached from the distal end of the main helical segment 101 when it slides on the main helical segment 101. In this way, when the guide wire penetrates the main helical segment 101, the auxiliary helical segment 102 can continue to maintain a helical shape under the action of the shaping wire 10202, and the main helical segment 101 can enter the blood vessel branches alone after being straightened by the guide wire. Preferably, when the main helical segment 101 is straightened by the guide wire to a suitable length, the helical segment fixing member 103 is blocked and limited, and then the two helical segments can be straightened at the same time.

[0059] In addition, a plurality of electrodes 104 are arranged on the main helical segment 101, and the auxiliary helical segment 102 can be provided with or without the electrodes 104. Preferably, the auxiliary helical segment 102 is provided with one or more electrodes 104. Any one of the electrodes 104 can be used for mapping or ablation. The electrodes 104 are generally ring electrodes, which are wrapped around the outer circumferential surface of the multi-lumen polymer tube material of each helical segment.

[0060] Optionally, the electrodes 104 on the main helical segment 101 are 2-8. The electrodes 104 are preferably uniformly arranged on the main helical segment 101, i.e. arranged at equal intervals or equal angles. The electrodes 104 are arranged on the main helical segment 101 to effectively adhere to the tissue. For example Figure 3 As shown, the electrodes 104 are arranged at the peak or valley positions of the main helical segment 101, or near the peak or valley positions.

[0061] Optionally, the electrodes 104 on the auxiliary helical segment 102 are 0-4, preferably 2-4. The electrodes 104 are arranged on the auxiliary helical segment 102 to effectively adhere to the tissue. For example Figure 5 As shown, the electrodes 104 are arranged at the peak or valley positions of the auxiliary helical segment 102, or near the peak or valley positions.

[0062] Turning back to Fig. 1, Figure 2 The main helical segment 101 is provided with a double-helical structure of a guide wire lumen 10101 and a guide wire lumen 10102 arranged separately. The double-helical structure of the guide wire lumen 10101 of the main helical segment 101 axially penetrates the main helical segment 101. The guide wire lumen 10102 of the main helical segment 101 generally only penetrates the proximal end of the main helical segment 101, but does not penetrate the distal end of the main helical segment 101. It should be noted that when the two helical segments need to be straightened or bent simultaneously, the helical segment fixing member 103 itself is provided with a guide wire channel coaxial with the double-helical structure of the guide wire lumen 10101 in the main helical segment 101, for the guide wire to pass out. Various guide wires can be arranged in the guide wire lumen 10102 of the main helical segment 101, including but not limited to electrode guide wires, for example, in some cases, temperature measuring guide wires, etc., which are not limited.

[0063] The double-helical structure of the guide wire lumen 10101 of the main helical segment 101 is used for the guide wire to pass through, and the guide wire moves in the double-helical structure of the guide wire lumen 10101 to control the double-helical structure 1 to be straightened or bent, thereby achieving single-helical straightening or double-helical straightening during the operation. It should be understood that when the guide wire penetrates the main helical segment 101, it can axially support the main helical segment 101 to elongate, and after the guide wire is withdrawn from the main helical segment 101, the main helical segment 101 is bent and recovered to a helical shape under the action of the shaping wire 10202 of the auxiliary helical segment 102 and the elastic recovery of the helical segment tube material itself.

[0064] Referring to Figure 4 and Figure 5 The auxiliary helical segment 102 is provided with at least a shaping wire cavity 10201, and a shaping wire 10202 is arranged in the shaping wire cavity 10201. Specifically, one end of the shaping wire 10202 is fixed to the distal end of the auxiliary helical segment 102, and the other end of the shaping wire 10202 is fixed to the proximal end of the auxiliary helical segment 102. The auxiliary helical segment 102 is kept in a helical state under the action of the shaping wire 10202, and at the same time, the auxiliary helical segment 102 enhances the supportability of the double helical structure 1 in the operation by the action of the shaping wire 10202, thereby increasing the adhesion of the electrode 104 to the tissue and improving the mapping and ablation efficiency while keeping the electrode segment soft and adaptive.

[0065] The main helical segment 101 basically does not need to be provided with a shaping wire 10202, because the shaping wire 10202 in the auxiliary helical segment 102 will simultaneously act on the main helical segment 101, thereby indirectly enhancing the supportability of the main helical segment 101 in the operation and ensuring that the electrode 104 on the main helical segment 101 can be well adhered to the tissue.

[0066] In some preferred embodiments, the electrode 104 is arranged on the auxiliary helical segment 102, which can make the double helical structure 1 arrange more electrodes 104 in the circumferential direction of the blood vessel, thereby increasing the treatment area covered by the helical segment electrode in the blood vessel and improving the surgical treatment effect.

[0067] The electrodes 104 on the main helical segment 101 and the electrodes 104 on the auxiliary helical segment 102 can be projected on the same projection plane and overlapped or staggered. The projection plane here refers to a plane perpendicular to the axis direction of the ablation catheter.

[0068] Especially, when the electrodes 104 on the main helical segment 101 and the electrodes 104 on the auxiliary helical segment 102 are projected on the same projection plane and staggered in the circumferential direction, the spatial positions of the electrodes on the two helical segments are complementary, which is more conducive to increasing the treatment area covered by the helical segment electrode in the blood vessel and realizing a continuous heat affected zone, thereby reducing the difficulty of finding the target point in the operation, further reducing the operation demand for twisting into place in the operation process, shortening the operation time, and improving the operation efficiency. The following is exemplarily described.

[0069] According to Figure 3 the exemplary embodiment described above, the main helical segment 101 is provided with four electrodes 104, and the four electrodes 104 are sequentially distributed along the main helical segment 101 from the distal end to the proximal end. The four electrodes 104 can be located at the 6 o'clock, 3 o'clock, 12 o'clock and 9 o'clock directions of the main helical segment 101, respectively.

[0070] As the auxiliary helical segment 102 is staggered between the main helical segments 101, if there is an electrode 104 on the auxiliary helical segment 102, then Figure 5 , the electrode 104 on the auxiliary helical segment 102 can be two, and the two electrodes 104 on the auxiliary helical segment 102 are located at the 9 o'clock and 6 o'clock directions of the auxiliary helical segment 102 from distal to proximal.

[0071] In other exemplary embodiments, three electrodes 104 are provided on the main helical segment 101, and the three electrodes 104 are sequentially distributed along the main helical segment 101 from distal to proximal, and the three electrodes 104 are located at the 12 o'clock, 4 o'clock and 8 o'clock directions of the main helical segment 101, respectively. At this time, the auxiliary helical segment 102 can also use three electrodes 104, and the three electrodes 104 on the auxiliary helical segment 102 are sequentially located at the 6 o'clock, 10 o'clock and 2 o'clock directions from distal to proximal.

[0072] However, those skilled in the art should know that the specific electrode distribution mode (including the number of electrodes and the position of the electrodes) can be flexibly adjusted according to actual needs, and is not limited to the cases listed in the above embodiments. Any one of the electrodes 104 can be controlled by the energy supply device. The electrodes 104 can be discharged simultaneously, discharged separately with a neutral electrode, or discharged between the electrodes 104, and the present application is not limited to this.

[0073] Next, referring to Figure 4 , in some embodiments, the auxiliary helical segment 102 is also provided with a wire lumen 10203 which is separate from the shaping wire lumen 10201. The wire lumen 10203 of the auxiliary helical segment 102 is also used to arrange various wires, such as electrode wires, temperature measuring wires, sensor wires, etc. The shaping wire lumen 10201 of the auxiliary helical segment 102 generally cannot be shared with the wire lumen 10203, because during use, the shaping wire 10202 is involved in straightening and restoring, and if shared, there may be a risk of wire failure due to friction.

[0074] Further, the wire lumen 10102 of the main helical segment 101 and the wire lumen 10203 of the auxiliary helical segment 102 eventually merge into one at the distal end of the bendable segment 2, i.e., the same wire channel can be provided in the bendable segment 2 and the catheter body 3, and the wire channel is divided into two at the distal end of the bendable segment 2, one of which is the wire lumen 10102 of the main helical segment 101, and the other of which is the wire lumen 10203 of the auxiliary helical segment 102. In this way, the wire can pass through the entire ablation catheter and eventually be connected to the control handle 4.

[0075] Specifically, the base portions of the main helical segment 101 and the auxiliary helical segment 102 are each made of a multi-lumen polymer tubing material, particularly a material with low hardness and good elasticity, such as polyurethane, polyamide, polypropylene, or other commonly used polymer materials. The diameter of each helical segment can be adjusted based on the intended use scenario. Optionally, the diameter of each helical segment is 2-6F, but this is not limited to the specification.

[0076] Preferably, the total length of the main helical segment 101 (particularly the helical segment length) is greater than or equal to the total length of the auxiliary helical segment 102 (particularly the helical segment length), allowing the main helical segment 101 to carry more electrodes 104 and cover a wider treatment area. In particular, in embodiments where the main helical segment 101 is straightened alone, a longer total length of the main helical segment 101 facilitates access to deeper blood vessels for treatment.

[0077] Preferably, the elasticity of the auxiliary helical segment 102 is less than that of the main helical segment 101. In particular, when the main helical segment 101 is independently straightened to enter a smaller blood vessel, the auxiliary helical segment 102, with its low elasticity, is less likely to follow the straightening of the main helical segment 101. If the auxiliary helical segment 102 is also straightened, the length required to enter the smaller blood vessel may be shortened. Optionally, the multi-lumen polymer tubing of the auxiliary helical segment 102 may be made of a polymer material with less elasticity than that of the main helical segment 101.

[0078] Continue to refer Figures 5 to 10 Optionally, a linear segment 10205 is provided at the distal end of the auxiliary helical segment 102. This arrangement, on the one hand, can make the total length of the helical segment of the auxiliary helical segment 102 shorter than the total length of the helical segment of the main helical segment 101, on the other hand, facilitates the helical segment fixing member 103 to connect the two helical segments, and on the other hand, can shorten the helical segment length of the shaping wire 10202 to appropriately reduce the radial support force of the entire helical segment. In this way, while ensuring the therapeutic effect, it avoids excessive radial support force from irritating blood vessels and causing spasms.

[0079] by Figure 8 For example, when the distal end of the auxiliary spiral segment 102 and the distal end of the main spiral segment 101 are connected through the spiral segment fixing member 103, the distal end face of the linear segment 10205 and the distal end face of the main spiral segment 101 are located in the same plane, so that the spiral segment fixing member 103 can more conveniently fix the distal ends of the two spiral segments together.

[0080] Based on Figure 10 As described, when the helical segment fixing member 103 is movably connected to the main helical segment 101 , the helical segment fixing member 103 can be directly disposed at the distal end of the linear segment 10205 and further sleeved on the distal region of the main helical segment 101 .

[0081] When the helical segment fixing member 103 is directly sleeved on the outside of the main helical segment 101, preferably, the distal end of the main helical segment 101 is provided with a distal end limiting structure 10104 for blocking the helical segment fixing member 103 at the distal end of the helical segment fixing member 103. Specifically, the maximum size of the distal end limiting structure 10104 is greater than the inner hole size of the helical segment fixing member 103, so that the helical segment fixing member 103 cannot be pulled out of the distal end of the main helical segment 101. In this embodiment, the helical segment fixing member 103 is arranged as an annular structure, directly sleeved on the outside of the main helical segment 101 and capable of sliding along the main helical segment 101, the inner hole diameter of the helical segment fixing member 103 is greater than the diameter of the pipe material of the main helical segment 101, and the outer contour size of the distal end limiting structure 10104 is greater than the inner hole diameter of the helical segment fixing member 103.

[0082] The distal end limiting structure 10104 itself leaves a guide wire cavity passage for the guide wire to pass out. The distal end limiting structure 10104 can be arranged at the distal end of the main helical segment 101 by various measures. The distal end limiting structure 10104 can be integrally formed with the pipe material of the main helical segment 101 or connected in a separate form. Alternatively, the distal end limiting structure 10104 is in the shape of a ball head. Alternatively, the distal end limiting structure 10104 is a molten ball or a glue ball, which can better protect the blood vessels. For example, the limiting molten ball is directly formed by melting the multi-cavity polymer pipe material or the glue ball is formed by coating glue. Of course, the ball head-shaped distal end limiting structure 10104 can also be fixed to the distal end of the main helical segment 101 by bonding, hot melting or welding process.

[0083] The helical segment fixing member 103 can be a metal structure or a polymer structure. The helical segment fixing member 103 is preferably directly fixed to the distal end of the shaping wire 10202, so that the helical segment fixing member 103 can also serve the function of fixing the shaping wire 10202. For example, a metal ring is directly curled from the distal end of the shaping wire 10202, and the metal ring constitutes the helical segment fixing member 103, or a polymer ring is directly fixed to the distal end of the shaping wire 10202 by bonding, hot melting or welding process, and the polymer ring constitutes the helical segment fixing member 103.

[0084] Continuing to refer to Figure 10 , preferably, the main helical segment 101 is provided with a proximal end limiting structure 10103 at the proximal end of the corresponding one electrode 104, and the proximal end limiting structure 10103 is used to block the helical segment fixing member 103 at the proximal end of the helical segment fixing member 103. Specifically, the maximum size of the proximal end limiting structure 10103 is greater than the inner hole size of the helical segment fixing member 103. The proximal end limiting structure 10103 is preferably arranged on the inside of the main helical segment 101 and does not face the tissue, so as not to protrude and cause damage to the tissue. In this way, the proximal end limiting of the helical segment fixing member 103 can be provided by the proximal end limiting structure 10103.

[0085] Therefore, when the helical segment fixing member 103 moves on the main helical segment 101 in the proximal direction until it is blocked by the proximal limiting structure 10103 and cannot continue to move in the proximal direction, the helical segment fixing member 103 achieves the limiting of the straightening of the main helical segment 101; after the helical segment fixing member 103 moves to contact the proximal limiting structure 10103, further straightening will straighten both helical segments at the same time.

[0086] Therefore, during use, when the guide wire passes through the main helical segment 101, only the main helical segment 101 is straightened, and the auxiliary helical segment 102 can remain in the original shape or the adaptive shape, so that the main helical segment 101 can reach blood vessels with smaller diameters; further, after the proximal limiting structure 10103 is provided, both helical segments can be straightened at the same time under expected conditions, and the diameter of the straightened double helical structure 1 will be smaller, which makes it easier to enter narrow blood vessels, and no additional force is generated on blood vessels with larger diameters.

[0087] Optionally, the proximal limiting structure 10103 is arranged at the proximal end of the second or fourth electrode 104 counted from the distal end to the proximal end of the main helical segment 101, but the position of the proximal limiting structure 10103 can be adjusted according to the straightening length of the main helical segment 101.

[0088] Preferably, the distance from the proximal limiting structure 10103 to the helical starting point of the main helical segment 101 is greater than or equal to the total length of the auxiliary helical segment 102. In this way, when the proximal limiting structure 10103 contacts the helical segment fixing member 103, the auxiliary helical segment 102 can be appropriately straightened, and the two helical segments can be straightened at the same time.

[0089] It should be noted that the specific structure of the above-mentioned distal limiting structure 10104 and the proximal limiting structure 10103 is not particularly limited, as long as it can block the helical segment fixing member 103.

[0090] In another aspect, for stimulation and ablation treatment, it is also necessary to reduce the damage of heat to the target tissue, and therefore, the ablation catheter of the embodiment preferably also has the function of perfusion cooling.

[0091] Reference Figure 6 and Figure 7In some embodiments, the inner part of at least one of the main helical segment 101 and the auxiliary helical segment 102 is further provided with an independent perfusion channel 105, and the surface of some corresponding electrodes 104 is provided with a perfusion through-hole 10401 in communication with the perfusion channel 105. The perfusion channel 105 is isolated from other cavities in the helical segment. In use, the cooling medium such as physiological saline is injected into the perfusion channel 105, and then flows out through the perfusion through-hole 10401 at the electrode 104 to achieve the cooling treatment of the target tissue. Here, since the electrodes 104 in the double helix structure 1 cannot be circumferentially attached to the tissue, only 1 / 2 to 3 / 4 of the surface area can be attached to the tissue, so perfusion is not required along the entire circumference of the electrode 104, and only the attached position needs to be perfused. Specifically, the electrode 104 is only provided with a perfusion through-hole 10401 on part of its surface (the surface that can be attached to the tissue, i.e. the outward surface), to ensure that the cooling medium such as physiological saline can reach the position where the electrode 104 is attached to the tissue.

[0092] On the other hand, with reference to Figure 8 and Figure 9 In some embodiments, the auxiliary helical segment 102 is further provided with a sensor cavity 10206. The shaping wire cavity 10201 can be shared with or separately provided from the sensor cavity 10206. At least one sensor 10207 is provided in the sensor cavity 10206. It should be understood that the sensor cavity 10206 is usually separately provided from the lead cavity 10203. In the present embodiment, the shaping wire cavity 10201 is separately provided from the sensor cavity 10206, and the sensor 10207 is provided outside the shaping wire 10202 to avoid the sensor 10207 from being additionally pressed to increase the measurement error. The sensor 10207 is only provided in the auxiliary helical segment 102, because the auxiliary helical segment 102 is more stable in form and causes less additional impact on the sensor 10207.

[0093] The sensor 10207 can be a magnetic positioning sensor or a pressure sensor. In practice, at least one of a magnetic positioning sensor and a pressure sensor can be provided in the sensor cavity 10206. The pressure sensor is provided on the inner side of the auxiliary helical segment 102 and can be used to monitor the blood pressure during the operation. The magnetic positioning sensor can locate the position and form of the helical segment.

[0094] Preferably, one or more sensors 10207 are provided in the sensor cavity 10206 along the helical region of the auxiliary helical segment 102, for example, the sensor 10207 is provided in at least one of the proximal end of the helical segment, the distal end of the helical segment and the middle position of the helical segment of the auxiliary helical segment 102. Optionally, the sensor 10207 is 1-3, preferably 2-3.

[0095] Preferably, at least two magnetic positioning sensors are arranged in the sensor cavity 10206, and the distance between the two farthest magnetic positioning sensors covers the entire helical area of the auxiliary helical segment 102. In this way, the three-dimensional magnetic navigation device can be used to locate the position of the double helix structure 1 in the body, map the electrode treatment points, and monitor the deformation of the auxiliary helical segment 102, thereby predicting the shape of the main helical segment 101 during the operation.

[0096] For ease of understanding, the bendable segment 2, the catheter body 3, and the control handle 4 are further described below.

[0097] Reference Figure 11 In some embodiments, the bendable segment 2 is composed of a helical butt joint segment 201 and a bendable multi-lumen tube 202 connected by adhesion or heat melting process. The helical butt joint segment 201 and the bendable multi-lumen tube 202 are made of medical polymer materials such as polyurethane, polyamide, and polypropylene. The helical butt joint segment 201 can be single-lumen or multi-lumen structure, and is fixedly connected to the proximal end of the double helix structure 1 and the distal end of the bendable multi-lumen tube 202 by adhesion or heat melting process. When the helical butt joint segment 201 is multi-lumen structure, an additional perfusion channel 105 can be provided to facilitate perfusion at the proximal end of the two helical segments during the operation, thereby reducing the risk of thrombosis.

[0098] According to Figure 11 As described above, the bendable segment 2 can be provided with a guide wire lumen 20201, a pull wire lumen 20202, and a guide wire lumen 20203 in the bendable multi-lumen tube 202. The guide wire lumen 20201 of the bendable segment 2 is coaxially connected to the guide wire lumen 10101 of the double helix structure in the main helical segment 101. The pull wire 204 is placed in the pull wire lumen 20202. The material of the pull wire 204 can be stainless steel wire or memory metal such as nickel-titanium alloy and copper-based alloy. The function of the pull wire 204 is to control the bending of the bendable segment 2. Various guide wires needed on the catheter can be placed in the guide wire lumen 20203 of the bendable segment 2, and the specific types of guide wires are not limited.

[0099] There are various ways to fix the pull wire 204. One way is to fix the distal end of the pull wire 204 directly to the shaping wire fixing member 10204, and the proximal end of the shaping wire 10202 is also fixed to the shaping wire fixing member 10204. For details, please refer to Figure 12 and Figure 13The pull wire 204 and the shaping wire 10202 can be fixed to the shaping wire fixing member 10204 by welding or other methods. Alternatively, the distal end of the pull wire 204 is directly fixed to the pull wire fixing member 20401, and the pull wire fixing member 20401 is fixed to the distal end of the flexible segment multi-lumen tube 202. Meanwhile, the proximal end of the shaping wire 10202 is directly fixed to the shaping wire fixing member 10204, and the shaping wire fixing member 10204 is fixed to the proximal end of the auxiliary helical segment 102. For details, please refer to Figure 12 and Figure 14 The shaping wire fixing member 10204 and the pull wire fixing member 20401 can be square, circular or other various shapes.

[0100] The above fixing methods can achieve that the pull wire 204 only drives the flexible segment 2 to deform without affecting the double helix structure 1.

[0101] The proximal end of the pull wire 204 is connected to the control handle 4, and the control handle 4 can be provided with corresponding operation mechanisms to control the pull wire 204.

[0102] It should also be understood that the proximal end of the guide wire lumen 20201 of the flexible segment 2 is also connected to a guide wire passage through the catheter body 3. Preferably, the guide wire passage in the catheter body 3 can be formed by a corresponding pipe material lap joint, such as polytetrafluoroethylene (PTFE) or polyimide or metal braided tube, etc. to provide a smooth guide wire passage, thereby providing a smooth guide wire passage for the use of guide wire during operation. The proximal end of the control handle 4 can be provided with corresponding interfaces according to functional needs, such as a saline irrigation port, a guide wire inlet, and a bending control operation piece, etc. The specific functions can be set according to actual conditions.

[0103] In the above embodiments, the guide wire is used as a separate accessory with the ablation catheter. When the guide wire is needed, the guide wire is inserted into the ablation catheter.

[0104] However, in other embodiments, the guide wire can be built-in the ablation catheter, so that the guide wire becomes a part of the ablation catheter integrated on the ablation catheter. Specifically, the ablation catheter of the present embodiment further comprises a guide wire, which sequentially passes through the guide wire passage of the catheter body 3, the guide wire lumen 20201 of the flexible segment 2 and the guide wire lumen 10101 of the double helix structure 1, and the proximal end of the guide wire is connected to the control handle 4. Optionally, a sliding member is provided on the control handle 4, and when the guide wire passes through the ablation catheter, the proximal end of the guide wire is connected to the sliding member, so that only the sliding member needs to be operated to adjust the position of the guide wire, so that the guide wire enters or exits the main helical segment 101. In this case, the guide wire is not a separate accessory, but a part of the ablation catheter.

[0105] Finally, taking renal artery ablation as an example, the use of the ablation catheter provided by each of the above embodiments is described:

[0106] In the operation, the double helix structure 1 is first straightened by the configured straightener 301 to enter the sheath tube, and after being unsheathed, the main helical segment 101 is straightened by the guide wire, driving the auxiliary helical segment 102 to be straightened synchronously, reducing the maximum diameter of the catheter, facilitating the movement of the catheter in the blood vessel;

[0107] Then, the catheter can be bent into the main trunk of the renal artery through guide wire guidance or the pull wire 204, and especially when the main helical segment 101 can be completely straightened independently of the auxiliary helical segment 102, the main helical segment 101 alone enters the renal artery branch when the catheter treatment segment is located at the end of the main trunk of the renal artery;

[0108] When the catheter treatment segment is located in the main trunk of the renal artery, the double helix shape of the treatment segment is straightened and restored by moving the guide wire, and the catheter treatment segment is moved from the distal end of the renal artery to the proximal end of the main trunk of the renal artery along the blood vessel, without the need for twisting operation, so as to realize continuous mapping and ablation of the blood vessel in the circumferential direction, reduce the difficulty of finding the target point in the operation, and improve the treatment area coverage.

[0109] In summary, according to the technical scheme provided by the embodiments of the present application, the ablation catheter provided by the present application can realize the complementation of the spatial positions of the two helical segments through the staggered arrangement of the two helical segments, so that the mapping and ablation treatment along the circumferential direction of the blood vessel can be realized without twisting operation, effectively reducing the difficulty of the operation and shortening the operation time. In addition, when the electrode 104 of the main helical segment 101 is insufficient in mapping and ablation, the electrode 104 of the auxiliary helical segment 102 can be used to supplement the mapping and ablation, and when the electrode 104 of the main helical segment 101 is not well attached, the auxiliary helical segment 102 can provide additional support, thereby enhancing the in-situ attachment and improving the mapping and ablation efficiency. In addition, by providing the helical segment fixing member 103, single helical straightening or synchronous straightening of the double helix can be realized, and especially the single helical straightening can realize the main helical segment 101 to reach the blood vessel branch that the double helix structure 1 cannot enter, thereby increasing the treatment range of the operation.

[0110] In general, the present application can enhance the support of the electrode area while keeping the helical segment soft and not easy to damage the tissue, increase the effective attachment, and at the same time, increase the treatment coverage area, and only axial control of the catheter is needed to realize cylindrical mapping and ablation along the inner wall of the blood vessel, thereby improving the poor twisting control performance caused by the long and thin catheter body.

[0111] It should be noted that the above several embodiments can be combined with each other. The above description is only a description of the preferred embodiments of the present application, and does not limit the scope of the present application in any way. Any modification or modification of the above-mentioned disclosure by a person skilled in the art belongs to the protection scope of the present application.

Claims

1. An ablation catheter, characterized by, The utility model relates to a kind of medical devices, including: Double helix structure, bendable section, catheter body and steering handle are sequentially connected from distal end to proximal end; The double helix structure includes main helix section and auxiliary helix section; The main helix section and the auxiliary helix section are distributed around the same axis in the same direction; The distal end of the auxiliary helix section and the distal end of the main helix section are connected by helix section fixing part, or the distal end of the auxiliary helix section is provided with helix section fixing part, and the helix section fixing part is movably connected with the main helix section; Multiple electrodes are provided on the main helix section; A guide wire lumen and a guide wire lumen are provided separately in the main helix section;A shaping wire lumen is provided in the auxiliary helix section;A shaping wire is provided in the shaping wire lumen.

2. The ablation catheter of claim 1, wherein, At least one electrode is provided on the auxiliary helix section, and a guide wire lumen is also provided in the auxiliary helix section separately from the shaping wire lumen;The projection of the electrodes on the main helix section and the electrodes on the auxiliary helix section on the same projection plane is staggered in the circumferential direction.

3. The ablation catheter of claim 2, wherein, The number of electrodes on the main helix section is 2-8, and the number of electrodes on the auxiliary helix section is not more than 4.

4. The ablation catheter of claim 2, wherein, An independent perfusion channel is also provided in at least one of the main helix section and the auxiliary helix section, and the surface of some of the electrodes is provided with a perfusion through hole communicating with the perfusion channel.

5. The ablation catheter of claim 1, wherein, The diameter of the main helix section and the diameter of the auxiliary helix section are the same, the pitch of the main helix section and the pitch of the auxiliary helix section are the same, and the helix starting point of the main helix section and the helix starting point of the auxiliary helix section differ by half the pitch.

6. The ablation catheter of claim 1, wherein, The total length of the main helix section is greater than or equal to the total length of the auxiliary helix section, and / or the elasticity of the auxiliary helix section is less than the elasticity of the main helix section.

7. The ablation catheter of claim 1, wherein, A linear section is provided at the distal end of the auxiliary helix section.

8. The ablation catheter of claim 1, wherein, A sensor cavity is also provided in the auxiliary helix section, which is shared or separately provided with the shaping wire lumen;At least one sensor is provided in the sensor cavity.

9. The ablation catheter of claim 8, wherein, The sensor is a magnetic positioning sensor or a pressure sensor, and at least one of the magnetic positioning sensor and the pressure sensor is provided in the sensor cavity, and the sensor is provided at at least one of the helix section proximal end, helix section distal end and helix section intermediate position of the auxiliary helix section in the sensor cavity.

10. The ablation catheter of claim 9, wherein, At least two magnetic positioning sensors are provided in the sensor cavity, and the distance between the two magnetic positioning sensors covers at least the entire helical region of the auxiliary helix section.

11. The ablation catheter of claim 8, wherein, 1-3 sensors are provided along the helical region of the auxiliary helix section in the sensor cavity.

12. The ablation catheter of claim 1, wherein, When the helix section fixing part is movably connected with the main helix section, the helix section fixing part is sleeved on the outside of the main helix section, the distal end of the main helix section is provided with a distal end limiting structure, and the distal end of the helix section fixing part is blocked by the distal end limiting structure.

13. The ablation catheter of claim 12, wherein, The distal end of the helix section fixing part is fixed with the distal end of the shaping wire, and / or the distal end limiting structure is a molten ball or a glue ball.

14. The ablation catheter of claim 12, wherein, The main helical section is provided with a proximal end limiting structure at the proximal end of the corresponding one of the electrodes, which is used to block the helical section fixing member at the proximal end of the helical section fixing member.

15. The ablation catheter of claim 14, wherein, The proximal end limiting structure is arranged at the proximal end of the second or fourth electrode counted from the distal end to the proximal end of the main helical section; and / or the distance from the proximal end limiting structure to the helical starting point of the main helical section is greater than or equal to the total length of the helical section of the auxiliary helical section.

16. The ablation catheter of claim 1, wherein, A guide wire is further included, which sequentially passes through the guide wire passage of the catheter body, the guide wire lumen of the bendable section and the guide wire lumen of the double helix structure, and the proximal end of the guide wire is connected with the steering handle.

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