CN105903117B

CN105903117B - Catheter tube

Info

Publication number: CN105903117B
Application number: CN201610218142.4A
Authority: CN
Inventors: 贾罗琦; 贾宗毅
Original assignee: Shanghai Kings Medical Technology Co ltd
Current assignee: Shanghai Kings Medical Technology Co ltd
Priority date: 2016-04-08
Filing date: 2016-04-08
Publication date: 2022-07-05
Anticipated expiration: 2036-04-08
Also published as: WO2017173995A1; CN105903117A

Abstract

The invention discloses a catheter with a bendable head and a variable bending radius, which comprises a main body and a head part, wherein the head part is positioned at the distal end of the main body and is connected with the main body, and the head part comprises: a base pipe having at least one bendable section; at least one set of traction ropes each secured to a respective one of the at least one bendable segment; a guidewire threaded into said central tube, said guidewire including a distal portion and a proximal portion connected, said distal portion having a hardness less than a hardness of said proximal portion; wherein the guide wire is movable relative to the central tube such that when the junction of the distal and proximal portions of the guide wire is at different locations of one of the at least one bendable segment, the one bendable segment can be bent at different radii by controlling the respective one of the at least one set of pulling cords. The catheter of the present invention can accommodate the penetration of vascular bifurcations of various shapes, angles and curved lengths.

Description

Catheter tube

Technical Field

The invention relates to a medical instrument, in particular to a catheter for a minimally invasive vascular interventional operation.

Background

Minimally invasive surgery has been popular in the 80's of the 20 th century, with interventional procedures being an important branch thereof. The intervention can be divided into vascular and non-vascular interventions. In recent years, Minimally invasive vascular interventional surgery (MIVS) has been widely used at home and abroad. The minimally invasive vascular interventional operation is that under the guidance of a medical image X-ray image in the operation process, a doctor inserts a catheter into a blood vessel, controls the motion direction of the front end of the catheter in vitro, and sends the catheter to a target blood vessel from a puncture part of a patient to perform corresponding operation treatment. The operation has the advantages of small wound, less bleeding, less pain of patients, quick postoperative recovery, safety, reliability and the like, and is applied to various clinical subjects, such as cardiovascular surgery, neurosurgery, obstetrics and gynecology, oncology, vascular surgery, ear-nose-throat surgery and the like.

The method of operation of endovascular interventions, from birth, is combined with the traditional method of trial selection of a guide wire in the head of the catheter tip into a vascular bifurcation by rotating the catheter and guide wire. The injury of the vessel wall caused by the rotation and the drawing and inserting of the catheter and the guide wire is the scraping injury to the blood vessel intima, the injury can be naturally repaired by human bodies, and the natural repair of the human bodies can cause the hyperplasia and the thickening of the blood vessel intima tissue and the new stenosis and blockage of the blood vessel inner diameter. This is also one of the major drawbacks of conventional intubation methods.

The traditional intubation method uses a rotating catheter to select to probe to enter the vessel bifurcation, an experienced doctor can perform probe penetration through multiple rotations, and a common novice doctor can perform probe penetration through a large amount of rotation, so that the scraping injury to the vessel wall can be known conceivably.

In addition, for a patient who is a little old, due to the fact that harmful impurities in blood are accumulated for a long time, a plurality of plaques are formed on the inner wall of a blood vessel, the traditional intubation method uses a rotating catheter and a guide wire to select to probe into the bifurcation of the blood vessel, the probability that the plaques are scraped is increased, the plaques possibly fall off and rush into a tiny blood vessel to form embolism, and sometimes even the life is directly endangered. Such extreme risk cases occur during intravascular clinical procedures, which are also a significant risk of intravascular interventional procedures.

In order to reduce the scratch injury of the catheter to the vessel wall, aiming at the defect that the catheter and the guide wire must be rotated in the traditional operation method of the endovascular intervention operation, the catheter with the head capable of being bent under the control is developed in the prior art. For example, chinese patent publication No. CN103372260a and U.S. patent publication No. US2008/0139999a1 both disclose catheters having controllable bending joints at the front ends thereof, and by providing joints having different hardness at the front ends of the catheters and controlling pulling ropes connected to the respective joints, it is possible to control bending angles of the respective joints, thereby enabling the catheters to be bent according to the trend of blood vessels. However, once the existing catheters are manufactured, the achievable bending parameters, especially the range of bending radii at certain bending angles, are substantially fixed, and the vessels in the human body are diverse, and there may be significant differences in shape, angle and bending radius between different vessels, which makes the existing catheters difficult or even forced to stop the operation when entering certain specific vessels, especially those with bending angles and/or bending radii outside the achievable range of the catheter. Thus, there is a need for a more versatile head bendable catheter.

Disclosure of Invention

In view of the above, the present invention provides a catheter with a bendable head and a variable bending radius.

To achieve the above object, the present invention provides a catheter comprising a main body and a head portion at a distal end of the main body and connected thereto, wherein the head portion comprises: a base pipe having at least one bendable section; at least one set of traction ropes each secured to a respective one of the at least one bendable segment; a guidewire threaded into said central tube, said guidewire including a distal portion and a proximal portion connected, said distal portion having a hardness less than a hardness of said proximal portion; wherein the guide wire is movable relative to the central tube such that when the junction of the distal and proximal portions of the guide wire is at different locations of one of the at least one bendable segment, the one bendable segment can be bent at different radii by controlling the respective one of the at least one set of pulling cords.

Optionally, the stiffness of the at least one bendable section increases sequentially in a distal to proximal direction.

Optionally, the proximal portion of the guidewire has a stiffness greater than a stiffness of at least one of the at least one bendable section.

Optionally, the at least one bendable section comprises a first bendable section at a distal end of the central tube and a second bendable section at a proximal end of the first bendable section and connected to the first bendable section; the at least one set of traction ropes includes a first set of traction ropes secured to the first bendable segment and a second set of traction ropes secured to the second bendable segment.

Optionally, the first bendable section has a stiffness that is less than a stiffness of the second bendable section.

Optionally, the first bendable segment is bendable at different radii by controlling the first set of pulling cords when the junction of the distal and proximal portions of the guidewire is at different locations of the first bendable segment.

Optionally, the second bendable segment is bendable at a different radius by controlling the second set of pulling cords when the junction of the distal and proximal portions of the guidewire is at a different location in the second bendable segment.

Optionally, the first bendable segment is also bendable independently of the second bendable segment by further controlling the first set of pull cords.

Optionally, the first and second flexible segments are connected to each other by a first and second connecting member, and the first and second flexible segments are connected to each other by a second and third connecting member.

Optionally, the first bendable section comprises at least one first guide element fixed to the first bendable section, each of the at least one first guide element has a central large hole and a plurality of peripheral small holes, the first bendable section passes through the central large hole of the first guide element, the number of the plurality of peripheral small holes of the first guide element is greater than or equal to the number of the first group of pulling ropes, and each pulling rope of the first group of pulling ropes passes through the corresponding peripheral small hole of the first guide element.

Optionally, the flexible segment further comprises at least one second guide element fixed to the second bendable segment, each of the at least one second guide element having a central large hole and a plurality of peripheral small holes, the second bendable segment passing through the central large hole of the second guide element, the plurality of peripheral small holes of the second guide element being equal to or greater than the sum of the number of the pulling ropes in the first group and the number of the pulling ropes in the second group, each pulling rope in the first group and each pulling rope in the second group passing through a corresponding peripheral small hole of the second guide element.

Optionally, a radiopaque marker is included on the head to indicate the direction of movement of the head.

Optionally, the radiopaque marker comprises a first marker portion and a second marker portion having different directions of extension, and the first marker portion is different from the second marker portion in at least one of length, width and shape.

Optionally, the catheter body has a central lumen and a plurality of peripheral lumens, the central tube being in communication with the central lumen, the at least one set of pull cords passing through one or more of the plurality of peripheral lumens.

The guide wires with the soft distal end parts and the hard proximal end parts are arranged in the central tube, so that various bending angles of the existing catheter can be realized, the bending radius of the catheter can be changed by adjusting the positions of the guide wires in the central tube, the head of the catheter can be combined and changed into various postures of the head of the catheter under the control of at least one group of traction ropes, the bifurcation penetration of blood vessels with various shapes, angles and bending radii is adapted, and the content of the bending change of the head of the catheter is greatly enriched. Therefore, the catheter head can be directly inserted into a target blood vessel through accurate micro-amplitude swinging, and the scraping injury of the catheter to the blood vessel wall is reduced to the maximum extent.

Drawings

FIG. 1 is a schematic view of a catheter of the present invention;

FIG. 2 is a schematic view of the internal structure of the head of the catheter shown in FIG. 1;

FIG. 3A is a schematic view illustrating a bending range of a conventional bendable joint;

FIGS. 3B to 3D are schematic views illustrating the bending range of the bendable section according to the present invention;

fig. 4A to 4C show guidewires made in different ways.

Detailed Description

The catheter of the present invention is described in further detail below with reference to the figures and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

The invention provides a catheter which is suitable for interventional operations, in particular to minimally invasive vascular interventional operations.

As shown in fig. 1, the catheter comprises a main body 2 and a head 1 which are connected, and the head 1 is used as a guide part to pass along a predetermined or real-time determined blood vessel path with the main body 2 under the control of an operator (such as a doctor) until reaching a target blood vessel during the delivery process of the catheter. The body 2 is typically a multi-lumen tube and has a long length to ensure that at least a part of the body 2 is outside the patient's body when the head 1 of the catheter reaches the target vessel, and only a small part of the body 2 connected to the head 1 is schematically shown in fig. 1, the actual length of which should not be limited thereto. When the head 1 of the catheter reaches the lesion site, surgical instruments, medicines, etc. may be delivered to the lesion site through a chamber (usually a central main chamber) in the main body 2 to treat the lesion site. The main body 2 (i.e. multilumen tubing) may also include a plurality of auxiliary lumens located around the periphery of the central main lumen for passage of a pull cord as described below and/or as a backup lumen, such as may be used as an endoscope working port.

For convenience of description, hereinafter, the end where the head 1 is located is defined as a distal end, i.e., an end away from the operator, and the end where the body 2 is located is defined as a proximal end, i.e., an end closer to the operator. Thus, the head 1 is located at the most distal end of the entire catheter.

It will be readily understood by those skilled in the art that whether the catheter can smoothly pass through the blood vessel along a predetermined path and whether unnecessary scraping damage can be caused to the blood vessel wall depends mainly on the maneuverability of the catheter head 1, and therefore the structure of the catheter head 1 and the manner of manipulation thereof will be described with emphasis on better embodying the benefits of the present invention.

Referring again to fig. 1, the catheter head 1 of the present embodiment includes a probe 10, a first bending segment 11 and a second bending segment 12 connected in sequence from the distal end to the proximal end, and the proximal end of the second bending segment 12 is connected to the distal end of the catheter main body 2. The probe 10 may be, for example, an intravascular interventional tactile probe with touch force measurement range and orientation information feedback, which is disclosed in chinese patent publication No. CN103877664A by the present inventor, the entire content of which is incorporated herein by reference, and the structure of the probe 10 is not described herein in detail.

The first bending joint 11 and the second bending joint 12 are shown in detail in fig. 2. The catheter head 1 comprises a central tube 20 extending through the first 11 and second 12 curved joints. The central tube 20 may be a hollow tube made of an elastic material so as to be bent by an external force. The distal end of the central tube 20 is fitted with the probe 10 as described above, and the proximal end of the central tube 20 can be inserted into and fixed to the main central chamber of the main body 2 (i.e., multilumen tubing) to communicate with the main central chamber, so that surgical instruments, medicines, etc. can enter the central tube 20 through the main central chamber.

In order to get the catheter head 1 into different vessel bifurcations, said head 1, and in particular the central tube 20, needs to be bent into different shapes, such as "C", "U", "S", etc. In the case of the "C" and "U" shapes, the tube 20 can be bent into the corresponding shape by applying a force in one direction, or by applying a resultant force in two or more directions toward the same side; but in the case of an "S" shape, it is necessary to apply forces in generally opposite directions to at least different portions of the base pipe 20. To this end, the base pipe 20 preferably has two or more bendable sections (bending sections) so that the bending direction of each bendable section can be controlled separately. In addition, to improve steerability, the bendable sections may be configured to have different stiffness, and preferably, the stiffness of each bendable section increases from the distal end to the proximal end such that each bendable section is capable of bending substantially independently of the other bendable sections.

In the embodiment shown in FIG. 2, the central tube 20 has two bendable sections, a first bendable section 21 and a second bendable section 22 from the distal end to the proximal end, wherein the first bendable section 21 has a stiffness that is less than the stiffness of the second bendable section 22. Specifically, the first bendable section 21 is formed from a portion of the base pipe 20a and the second bendable section is formed from another portion of the base pipe 20b plus a sleeve 23. When more bendable sections are desired, the stiffness can be varied by sleeving different central tube sections with different thicknesses or different numbers of sleeves.

In addition, a plurality of bendable sections having successively increasing stiffness may also be made by, among other things: for example, the central tube 20 corresponding to different bendable sections is manufactured by a high polymer material integral injection molding mode, and the outer diameters of the corresponding parts of the central tube are sequentially increased; different areas are perforated on the central tube 20 and/or the sleeve 23 with different perforation densities, and the places with more perforations have lower hardness than the places with less or no perforations; sleeving sleeves 23 with sequentially hardened materials on the central tube 20 from the far end to the near end corresponding to different bendable sections, wherein each sleeve 23 can be made of a high-molecular elastic material with different hardness; the central tube 20 is divided into two or more segments from the distal end to the proximal end, the segments having sequentially hardened hardness, and the adjacent segments are connected in a splicing manner or an insertion manner. The above and further embodiments of achieving progressively stiffer bendable sections can be seen in the inventor's application of invention publication No. CN103372260A, which is incorporated herein by reference in its entirety.

With continued reference to fig. 2, the catheter further includes a first set of pull cords 24 secured to the distal end of the first bendable section 21 by a first fastener and a second set of pull cords 25 secured to the distal end of the second bendable section 22 by a second fastener. Specifically, the first fastening member is a first flange 26 having a central large hole (not shown) for the first bendable section 21 (i.e., the central tube portion 20a) to pass through, and a plurality of peripheral small holes (not shown) for the ends of the first set of pulling cords 24 to pass through and be tied off for fastening. The second fastener is a second flange 27 having a central large hole 27a for the second bendable segment 22 (i.e., the central tube portion 20b and the sleeve 23) to pass through, and a plurality of peripheral

small holes

27b and 27c, wherein the peripheral small holes 27b are used for the first set of pulling ropes 24 to pass through, and the peripheral small holes 27c are used for the second set of pulling ropes 25 to pass through and be tied off for fastening. Although the pull cord is described herein as being secured by a knot, the invention is not so limited and the pull cord may be secured to the fastener by any means known in the art, such as riveting, gluing, by an auxiliary connector, and the like. Accordingly, the fixing member may not be provided with a peripheral eyelet through which the end of the pulling rope is passed for knotting, or the peripheral eyelet may be replaced with a connecting member matching the connecting member at the end of the pulling rope.

In order to avoid interference between the pulling ropes and influence on the control accuracy, it is preferable to arrange the pulling ropes in the first group of pulling ropes 24 and the pulling ropes in the second group of pulling ropes 25 in a staggered manner, for example, in an alternating manner and in a uniformly distributed manner on the outer circumference of the central tube 20. Optionally, one or more guide elements may be attached to the first and/or second flexible segments for guiding the direction of extension of the pulling cords to further avoid interference between adjacent pulling cords. As shown in fig. 2, the guiding element may not be necessary due to the short length of the first bendable section 21, whereas the length of the second bendable section 22 is relatively long, and therefore one or more guiding elements are preferably provided. In the embodiment shown in fig. 2, a third flange 28 is provided as a guide element in a substantially central position of the second bendable section 22. The third flange 28 has a central large aperture 28a for the second bendable section 22 to pass through and a plurality of peripheral

small apertures

28b and 28c, wherein the peripheral small apertures 28b are for the first set of pulling cords 24 to pass through and the peripheral small apertures 28c are for the second set of pulling cords 25 to pass through. In this way, the respective traction ropes of the first and second groups of

traction ropes

24, 25 do not interfere with each other.

The first and second groups of

pull cords

24 and 25 shown in fig. 2 each have four pull cords, and the four pull cords in each group are evenly distributed around the central tube 20. Taking the first bendable section 21 as an example, when any one of the first group of pulling ropes 24 is pulled, the distal end of the first bendable section 21 bends from the side where the pulling rope is located to the proximal direction. When any two adjacent pull cords of the first set of pull cords 24 are pulled, the distal end of the first flexible segment 21 can be bent in a proximal direction from either side between the two pull cords, as desired. Similarly, the distal end of the second flexible segment 22 can be bent in any direction by manipulating the second set of pull cords 25. The distal end of the first bendable section 21 can be bent into an "S" shape when the distal end of the second bendable section 22 is bent in a direction substantially opposite to the bending direction of the distal end.

It will be readily understood by those skilled in the art that when three or more pull cords are included in a group of pull cords, any directional bending of the bendable segment can be achieved, whether or not the pull cords are evenly distributed. However, in order to reduce the manipulation difficulty and improve the manipulation efficiency, it is preferable to use an even number of pulling ropes greater than or equal to four and to distribute the pulling ropes uniformly, so that which pulling rope or pulling ropes needs to be pulled and the pulling force of each pulling rope can be easily determined according to the direction and angle in which the head of the catheter needs to be bent.

Although the present embodiment is described as having four pulling ropes per group of pulling ropes and it is recommended to use an even number of pulling ropes equal to or greater than four, the present invention is not limited thereto. In fact, the invention can be practiced with fewer than four pull cords. For example, a pulling rope is fixed at the distal end of the first bendable section 21, and the distal end of the first bendable section 21 can be bent toward the tightening direction of the pulling rope by pulling; the two pulling ropes are fixed at the far end of the first bendable section 21, and the far end of the first bendable section 21 can be bent towards two corresponding directions by respectively pulling the two pulling ropes; if one of the two pulling ropes is fixed at the far end of the first bendable section 21 and the other pulling rope is fixed at the far end of the second bendable section 22, the two bending arcs in opposite directions can be bent by the pulling of the two pulling ropes, namely, an S shape can be bent; three pulling ropes are fixed at the far end of the first bendable section 21, and the first bendable section 21 can do 360-degree circumferential motion by taking the central tube 20 as an axis after being bent by sequentially pulling and releasing the pulling ropes; six pulling ropes are adopted, one group of three pulling ropes is respectively fixed at the far ends of the first bendable section 21 and the second bendable section 22, and the pulling ropes are sequentially combined for pulling and releasing, so that the catheter head 1 can be bent into an S shape and then can do 360-degree circumferential motion by taking the central tube 20 as an axis, or the catheter head can be bent into various forms of S shapes with the upper part and the lower part having deflection angles.

The catheter head 1 of the present invention can be bent in various shapes at any angle and in any direction under the control of the pulling rope. How the bending radius or the bending arc length of the bendable section is changed by the guide wire will be explained in detail below.

As mentioned in the background, although the catheters disclosed in CN103372260a and US2008/0139999a1 can be bent at different angles in various directions under the control of the pulling rope, as shown in fig. 3A, the bending motion of each controllable bending joint is supported by the proximal end point a of the joint, and once the catheter is manufactured, the bending arc length of each controllable bending joint is fixed and is substantially equal to the length of the controllable bending joint, and correspondingly, the bending radius of each controllable bending joint at a certain bending angle is also substantially fixed. The solid line in FIG. 3A shows radius R1 when the controlled bend joint is bent 90 degrees.

Unlike the existing catheter, the catheter of the present invention further includes a guide wire 30 (see fig. 4A to 4C) which penetrates into the central tube 20 and is movable relative to the central tube 20, wherein the guide wire 30 includes a distal portion (distal portion)31 and a proximal portion (proximal portion)32 which are connected, and the hardness of the distal portion 31 is smaller than that of the proximal portion 32. By varying the location of the junction 33 of the distal portion 31 and the proximal portion 32 within the bendable section, the location of the "fulcrum" can be varied, thereby enabling the same bendable section to bend out of any desired radius or arc length. Fig. 3B to 3D show a schematic view of the bending range of the bendable section at different positions (i.e., corresponding to the fulcrum B, C, D) at the junction 33 of the distal and proximal wire portions, respectively, within the bendable section, and the solid lines in fig. 3B to 3D show the radii R2, R3, R4, respectively, at which the bendable section bends 90 degrees. As can be seen from comparing fig. 3A with fig. 3B to 3D, not only the position of the fulcrum but also, correspondingly, the bending arc length of the bendable section and the bending radius at a certain bending angle can be arbitrarily changed when the guide wire of the present invention is used. The significant advantage of the catheter head of the invention in terms of maneuverability can thus be clearly seen.

With respect to the specific structure and manner of making the guide wire 30, as shown in fig. 4A, for example, a first material with a lower hardness may be used to make the distal portion 31 of the guide wire, a second material with a higher hardness may be used to make the proximal portion 32, and the two portions may be spliced, adhered, or welded together to form the guide wire 30. Preferably, the distal portion 31 and the proximal portion 32 have substantially the same outer diameter at the junction 33 so that the joined two portions form a guidewire 30 having a smooth outer surface without any corners or protrusions at the junction 33 of the two

portions

31 and 32 to cause unnecessary damage to the vessel wall. In addition, the distal end 34 of the distal portion 31 of the guidewire 30 may be rounded to avoid unnecessary damage to the vessel wall. Because of the different stiffness of the distal section 31 and the proximal section 32, a Duton zone is formed at the junction 33 of the two. When the guide wire 30 is inserted into the deflectable segment of the central tube 20 and the corresponding pull cord is pulled, the distal portion 31 (which is softer) of the guide wire is pulled to bend with the deflectable segment, while the proximal portion 32 (which is stiffer) serves as a support and is substantially non-bendable with the deflectable segment. To ensure that the proximal portion 32 of the guidewire has sufficient support strength, the proximal portion 32 preferably has a higher stiffness than either of the bendable sections. The stiffness of the distal portion 31 is not so limited and may be higher or lower than any of the bendable section so long as the distal portion 31 is capable of being stretch-bent along with the bendable section.

Another example of a guidewire is shown in fig. 4B, where guidewire 30 can be made of the same material, such that distal portion 31 has a smaller outer diameter than proximal portion 32, thereby providing distal portion 31 with a lower stiffness than proximal portion 32. Likewise, to avoid unnecessary damage to the vessel wall by the guidewire, the distal end 34 of the guidewire 30 and the junction 33 of the distal portion 31 and the proximal portion 32 can be made as smooth as possible to avoid sharp corners or protrusions. In this case, the junction 33 of the distal portion 31 and the proximal portion 32 forms a very short transition zone that has little effect on the wire changing the bend radius or arc length of the bendable section. When having a transition region, the guidewire can be made to have a natural transition curvature when bent. In addition, a sheath 35 of soft material may be placed over distal portion 31 to streamline the distal end of the guidewire.

As yet another example of a guidewire, shown in FIG. 4C, a flexible filament 37 is inserted intermediate a hollow capillary 36, the portion of the flexible filament 37 extending out of the capillary 36 forming the distal portion 31 of the guidewire, and the capillary 36 and its surrounding portion of the flexible filament 37 together forming the proximal portion 32 of the guidewire. Likewise, to avoid unnecessary damage to the vessel wall by the guidewire, the distal end of the capillary 36 may be shaped as a ramp and the distal end of the flexible filament 37 may be shaped as a circular arc. Here, capillary 36 and flexible filament 37 may be fixedly attached to each other such that the length of the portion of flexible filament 37 that extends out of capillary 36 is fixed, or capillary 36 and flexible filament 37 may not be fixedly attached such that the length of the portion of flexible filament 37 that extends out of capillary 36 may be adjusted by changing the relative position between capillary 36 and flexible filament 37. The advantages of this adjustable length design will be described below.

In addition to the various guidewires 30 shown in fig. 4A-4C, guidewires 30 having portions of different stiffness may be made using any one or combination of the previously described ways of making multiple bendable segments having different stiffness, or may be made using any other means known in the art and not described in detail herein.

In addition to the ability of the guidewire 30 to vary the bend radius or arc length of the bendable segment, an important function is to line the center tube 20 so that the center tube 20 does not collapse or wrinkle. Since the central tube 20 is a hollow tube, it can be easily collapsed and wrinkled without internal filler, and the central tube 20 can be supported and protected by lining the distal end portion 31 of the guide wire. To this end, the distal portion 31 of the guide wire 30 should be of sufficient length such that the distal portion 31 lines the bendable segment and the remainder of the bendable segment distal thereto, regardless of which bendable segment the junction 33 of the distal portion 31 and the proximal portion 32 is located in. For example, for the catheter head 1 shown in fig. 2 having two bendable sections, when the junction 33 of the distal wire portion 31 and the proximal wire portion 32 is located in the second bendable section 22, the distal wire portion 31 can line at least the entire first bendable section 21 and can also extend slightly beyond the distal end of the first bendable section 21. For a catheter head having three flexible segments (first, second, and third flexible segments in sequence from distal to proximal), when the junction 33 of the distal portion 31 of the guidewire and the proximal portion 32 is located in the third flexible segment, the distal portion 31 can line at least the entire second and first flexible segments, and can extend slightly beyond the distal end of the first flexible segment.

In order to ensure the said cushioning effect of the distal portion 31 of the guide wire, it is possible that for a guide wire with an unadjustable length, when the junction of the distal portion 31 and the proximal portion 32 is located in the first bendable section 21, the distal portion 31 will extend a longer distance beyond the first bendable section 21 and into the portion of the probe 10, which requires a combination of the size of the bendable sections, the size of the distal portion of the guide wire, and the size of the probe in the sizing process to ensure that the guide wire 30 will not extend too long out of the distal end of the probe 10 during its movement relative to the central tube 20 to affect the bending of the catheter head or damage to the vessel wall.

In this case, it would be advantageous to use an adjustable length guidewire as shown in fig. 4C, which allows the length of the distal portion 31 of the guidewire to be adjusted in real time during the procedure, thereby ensuring a cushioning effect without passing through the probe 10 for an excessive distance, and allowing for more flexibility in the sizing of various portions of the catheter.

Referring again to fig. 2, the catheter may also include a radiopaque marker 40 near the distal end of the head for indicating the current phase of the catheter head 1. The radiopaque marker 40 is made of a radiopaque material, such as a metal, metal mixture, metal compound, or the like. In order to be able to indicate the current phase, not just the position, of the catheter head 1, the radiopaque marker 40 comprises a first marker part 41 and a second marker part 42 having different directions of extension, and at least one of the length, width and shape of the first marker part 41 is different from the second marker part 42. Preferably, the first marker segment 41 may be disposed axially of the base pipe 20 and have a first characteristic that may be determined by one or more of the length, width and shape of the first marker segment 41, e.g., the first marker segment 41 is one or more lines; the second marker segment 42 may be disposed circumferentially or radially of the base pipe 20 and have a second characteristic that may also be determined by one or more of the length, width and shape of the second marker segment 42, e.g., the second marker segment 42 is a rectangular shaped marker. The first and second flag portions 41 and 42 may be disposed in connection or separately. The position of the radiopaque marker 40 is clearly discernible by X-ray imaging and, due to the different characteristics of the first and second marker portions 41, 42, it can be readily discerned which is an axial marker and which is a circumferential or radial marker, thus determining the current phase of the catheter head 1.

One specific radiopaque marker 40 is made, for example, as shown in figure 2, by providing a third flange 43 at the distal end of the first bendable section 21, the third flange 43 also passing over the central tube 20 and being secured to the central tube 20. The first mark part 41 is formed by vertically inserting metal wires into one or a plurality of small holes of the third flange 43, and then the second mark part 42 along the circumferential direction is formed by cutting a veneer made of a material doped with barium sulfate into transverse strips and pasting the transverse strips on the periphery of the third flange 43, wherein the veneer can cover half circumference of the third flange 43 to 1/4 circumference. Thus, the radiopaque marker 40 is formed in an "L" shape, which visually indicates the phase of the catheter head, and then determines which direction the catheter head is bent and which pulling cord or cords are pulled.

Although the embodiment is described as using two differently oriented, differently characterized marker portions to form the radiopaque marker 40, the invention is not so limited and other numbers, orientations, or shapes of markers may be used to assist the operator in determining which direction the catheter head is to be bent and in prompting the operator as to which pull cord to maneuver.

In summary, in the invention, the guide wire with the softer distal end part and the harder proximal end part is arranged in the central tube, so that various bending angles of the existing catheter can be realized, and the bending radius or arc length of the catheter can be changed by adjusting the position of the guide wire in the central tube, so that the head of the catheter can be combined and changed into various postures of the head of the catheter under the control of at least one group of traction ropes, and different requirements of bifurcation parts of blood vessels with different diameters on the bending direction, the bending angle and the bending radius of the interventional catheter can be met.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A catheter comprising a body and a head at a distal end of the body and connected thereto, the head comprising:

a base pipe having at least one bendable section;

at least one set of traction ropes each secured to a respective one of the at least one bendable segment;

a guidewire threaded into said central tube, said guidewire including a distal portion and a proximal portion connected, said distal portion having a hardness less than a hardness of said proximal portion;

wherein the guide wire is movable relative to the central tube such that when the junction of the distal and proximal portions of the guide wire is at different locations of one of the at least one bendable segment, the one bendable segment can be bent at different radii by controlling the respective one of the at least one set of pulling cords.

2. The catheter of claim 1, wherein the stiffness of the at least one bendable section increases sequentially in a distal to proximal direction.

3. The catheter of claim 1 or 2, wherein a proximal portion of the guidewire has a stiffness greater than a stiffness of at least one of the at least one bendable section.

4. The catheter of claim 1, wherein the at least one bendable section comprises a first bendable section at a distal end of a central tube and a second bendable section proximal to and connected to the first bendable section; the at least one set of traction ropes includes a first set of traction ropes secured to the first bendable segment and a second set of traction ropes secured to the second bendable segment.

5. Catheter according to claim 4, wherein the first bendable section has a stiffness less than a stiffness of the second bendable section.

6. The catheter of claim 4 or 5, wherein the first bendable section is bendable at different radii by controlling the first set of pulling cords when the junction of the distal and proximal portions of the guidewire is at different locations of the first bendable section.

7. The catheter of claim 4 or 5, wherein the second bendable section is bendable at different radii by controlling the second set of pulling cords when the junction of the distal and proximal portions of the guidewire is at different locations of the second bendable section.

8. The catheter of claim 7, wherein said first bendable segment is further bendable independently of said second bendable segment by further controlling said first set of pull cords.

9. The catheter of claim 4, further comprising a first fastener fixed at a distal end of the first bendable segment, and a second fastener fixed at a distal end of the second bendable segment, the first set of pulling cords being fixed by the first fastener to the distal end of the first bendable segment, the second set of pulling cords being fixed by the second fastener to the distal end of the second bendable segment.

10. The catheter of claim 9, further comprising at least one first guide element secured to the first bendable segment, each of the at least one first guide element having a central large aperture and a plurality of peripheral small apertures, the first bendable segment passing through the central large aperture of the first guide element, the plurality of peripheral small apertures of the first guide element being greater than or equal to the number of pull cords of the first set of pull cords, each pull cord of the first set of pull cords passing through a respective peripheral small aperture of the first guide element.

11. The catheter of claim 9 or 10, further comprising at least one second guide element secured to the second bendable segment, each of the at least one second guide element having a central large aperture and a plurality of peripheral small apertures, the second bendable segment passing through the central large aperture of the second guide element, the plurality of peripheral small apertures of the second guide element being greater than or equal to the sum of the number of pull cords of the first set of pull cords and the number of pull cords of the second set of pull cords, each pull cord of the first set of pull cords and each pull cord of the second set of pull cords passing through a respective peripheral small aperture of the second guide element.

12. The catheter of claim 1, further comprising a radiopaque marker on the head for indicating the direction of movement of the head.

13. The catheter of claim 12, wherein the radiopaque marker comprises a first marker portion and a second marker portion having different directions of extension, and wherein at least one of the length, width and shape of the first marker portion is different than the second marker portion.

14. The catheter of claim 1, wherein the catheter body has a central lumen and a plurality of peripheral lumens, the central tube being in communication with the central lumen, the at least one set of pull cords passing through one or more of the plurality of peripheral lumens.