CN220477935U

CN220477935U - Double-cavity microcatheter

Info

Publication number: CN220477935U
Application number: CN202222344567.3U
Authority: CN
Inventors: 史正涛; 张鹏涛; 张玉玺
Original assignee: Insight Lifetech Co Ltd
Current assignee: Insight Lifetech Co Ltd
Priority date: 2022-09-02
Filing date: 2022-09-02
Publication date: 2024-02-13
Anticipated expiration: 2032-09-02

Abstract

The present application relates to a dual lumen microcatheter. The double-cavity microcatheter comprises a first tube body, wherein the first tube body comprises a proximal end section, a middle section and a distal end section which are sequentially connected; part or all of the proximal section is a variable diameter portion, the inner diameter of which gradually decreases from the proximal end to the distal end. The scheme that this application provided can satisfy simultaneously and have certain propelling movement intensity promptly, can make the requirement that hard CTO seal wire got into smoothly again.

Description

Double-cavity microcatheter

Technical Field

The application relates to the technical field of medical instruments, in particular to a double-cavity microcatheter.

Background

In Percutaneous Coronary Intervention (PCI), single-use microcatheters (including single-lumen microcatheters and dual-lumen microcatheters) are often used in chronic total occlusion lesions (CTOs) to assist in guiding the wire to the proximal end of calcification, torturous lesions in the blood vessel, and even through the lesion site. Compared with a single-cavity microcatheter, the double-cavity microcatheter can be simultaneously matched with two guide wires and provides back-to-back strong support due to the double-cavity characteristic, so that the double-cavity microcatheter has unique advantages in severe calcification, long lesions, bifurcation lesions and even twisted blood vessels. Such as access to branch occlusion vessels (access to side Branch), branch vessel anchoring (side Branch ancher technology), parallel guidewire techniques (parallelwire), reverse guidewire techniques (Reverse Wire), and Stent mesh re-passage techniques (Stent re-cross), among others. Because dual-lumen microcatheters are primarily used to address the above "difficult and complicated conditions," dual-lumen microcatheters are often used with stiffer, sharper-ended, and shaped CTO guidewires.

In order to ensure that the proximal end of the double-cavity microcatheter has certain pushing strength, the outer diameter of the proximal end of the double-cavity microcatheter needs to be as small as possible; in order to allow the shaped (and in particular the stiffer) CTO guide wire to smoothly enter the lumen of the proximal end of the dual-lumen microcatheter, it is desirable that the lumen of the dual-lumen microcatheter be as large as possible (i.e., the inner diameter be as large as possible). However, the outer diameter of the catheter is necessarily increased while the inner diameter of the lumen is increased, so that the existing double-lumen microcatheter cannot simultaneously meet the requirements of certain pushing strength and smooth entering of a hard CTO guide wire.

Disclosure of Invention

In order to solve or partially solve the problems existing in the related art, the application provides a double-cavity microcatheter which can simultaneously meet the requirements of having certain pushing strength and enabling a hard CTO guide wire to smoothly enter.

The first aspect of the present application provides a dual-lumen microcatheter comprising a first tube comprising a proximal section, a middle section and a distal section connected in sequence; part or all of the proximal section is a variable diameter portion, the inner diameter of which gradually decreases from the proximal end to the distal end.

In some embodiments, the outer diameter of the reducing portion remains constant from the proximal end to the distal end, and the outer diameter of the reducing portion is equal to the outer diameter of the intermediate section.

In some embodiments:

one part of the proximal section is a reducing part, and the other part is a straight pipe part connected with the reducing part in the length direction of the proximal section; the outer diameter of the straight pipe part is equal to that of the reducing part; the method comprises the steps of,

one end of the straight pipe part, which is far away from the reducing part, is connected with the catheter seat, and one end of the reducing part, which is far away from the straight pipe part, is connected with the middle section; or one end of the straight pipe part far away from the reducing part is connected with the middle section, and one end of the reducing part far away from the straight pipe part is connected with the catheter seat.

In some embodiments, the proximal segment, the intermediate segment, and the distal segment each comprise an inner layer, a braid, and an outer layer disposed sequentially from inside to outside.

In some embodiments, when the end of the straight tube portion away from the reducing portion is connected to the catheter hub and the end of the reducing portion away from the straight tube portion is connected to the intermediate section, the inner layer, the braid and the outer layer of the proximal section are a first inner layer, a first braid and a first outer layer, respectively; a first transition cavity is formed between the first inner layer and the first braiding layer of the reducing part, and the first outer layer of the reducing part penetrates into the first transition cavity through the first braiding layer and is connected with the first inner layer.

In some embodiments, the inner layer, the woven layer, and the outer layer of the intermediate section are a second inner layer, a second woven layer, and a second outer layer, respectively, formed by the first inner layer, the first woven layer, and the first outer layer extending to the intermediate section; and the middle section further comprises a second spring layer, wherein the second spring layer is arranged between the second inner layer and the second braiding layer.

In some embodiments, the second spring layer does not extend into the first transition chamber.

In some embodiments, the inner layer, the braid, and the outer layer of the distal segment are a third inner layer, a third braid, and a third outer layer, respectively; and the third inner layer, the third braiding layer and the third outer layer are respectively formed by extending the second inner layer, the second braiding layer and the second outer layer to the distal end section, a second transition cavity is formed between the third inner layer and the third braiding layer, and the third outer layer penetrates into the second transition cavity through the third braiding layer and is connected with the third inner layer.

In some embodiments, the second spring layer does not extend into the second transition chamber.

In some embodiments, the dual-lumen microcatheter further comprises a second tube connected to the distal segment, the second tube comprising a fourth inner layer and a fourth outer layer connected in sequence from inside to outside, the fourth outer layer being connected to an outer surface of the distal segment.

In some embodiments, the outer diameter of the reducing portion tapers from the proximal end to the distal end, and the outer diameter of the distal end of the reducing portion is equal to the outer diameter of the intermediate section.

In some embodiments:

one part of the proximal section is a reducing part, and the other part is a straight pipe part; the outer diameter of the straight pipe part is equal to that of the far end of the reducing part; the method comprises the steps of,

one end of the straight pipe part is connected with the variable-diameter part in the length direction of the proximal section, the other end of the straight pipe part is connected with the middle section, and the outer diameters of the straight pipe part and the middle section are equal; one end of the reducing part, which is far away from the straight pipe part, is connected with the catheter seat.

In some embodiments, the thickness of the variable diameter portion is equal to the thickness of the straight tube portion; and/or the reducing part is made of ductile resin.

In some embodiments, the straight tube portion, the intermediate section, and the distal section each comprise an inner layer, a braid, and an outer layer disposed in sequence from inside to outside.

In some embodiments, the inner layer, the braid and the outer layer of the straight tube portion are a first inner layer, a first braid and a first outer layer, respectively; and the straight tube portion further includes a first spring layer disposed between the first inner layer and the first braid.

In some embodiments, the inner layer, the braid, and the outer layer of the intermediate section are a second inner layer, a second braid, and a second outer layer, respectively; the intermediate section further includes a second spring layer disposed between the second inner layer and the second braid; and the second inner layer, the second spring layer, the second woven layer and the second outer layer are formed by extending the first inner layer, the first spring layer, the first woven layer and the first outer layer to the middle section respectively.

The technical scheme that this application provided can include following beneficial effect: according to the embodiment of the application, the part or the whole of the proximal section forms the reducing part through the reducing design, the inner cavity of the proximal end (close to the catheter seat) of the reducing part is enlarged, so that the hard CTO guide wire can smoothly enter the proximal section, a user can select more types of CTO guide wires, and the effect of being compatible with various CTO guide wires is achieved. And the inner diameter of the variable-diameter part is gradually reduced from the proximal end to the distal end, so that the proximal end section can be gradually transited to the middle section, stress concentration is avoided, and meanwhile, the guide wire entering path is optimized. Further, the distal end of the variable diameter portion is directly or indirectly connected to the intermediate section, that is, the outer diameter of the distal end of the variable diameter portion must be equal to the outer diameter of the intermediate section, enabling the inner diameter to be enlarged without enlarging the outer diameter. Therefore, the double-cavity microcatheter provided by the embodiment of the application can simultaneously meet the requirements of having certain pushing strength and enabling the hard CTO guide wire to enter smoothly.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.

FIG. 1 is a schematic structural view of a dual lumen microcatheter shown in an embodiment of the present application;

FIG. 2 is a schematic structural view of the proximal section shown in FIG. 1;

FIG. 3 is a schematic structural view of the intermediate section shown in FIG. 1;

FIG. 4 is a schematic structural view of the distal segment shown in FIG. 1;

FIG. 5 is another schematic structural view of a dual lumen microcatheter shown in an embodiment of the present application;

fig. 6 is a schematic structural view of the proximal section shown in fig. 5.

Reference numerals: 1. a first tube body; s1, a proximal end section; b1, reducing part; z1, straight tube portion; 10. a first inner layer; 11. a first braid; 12. a first outer layer; 13. a first transition chamber; 14. a first spring layer; s2, an intermediate section; 20. a second inner layer; 21. a second spring layer; 22. a second braid; 23. a second outer layer; s3, a distal end section; 30. a third inner layer; 31. a third braid; 32. a third outer layer; 33. a second transition chamber; 2. a second tube body; 40. a fourth inner layer; 41. a fourth outer layer; 3. a catheter hub.

Detailed Description

Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, a first message may also be referred to as a second message, and similarly, a second message may also be referred to as a first message, without departing from the scope of the present application. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the description of the present application, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected or detachably connected or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

To ensure passability of the dual-lumen microcatheter and instrument compatibility within the guide catheter, it is desirable that the outer diameter of the proximal end of the dual-lumen microcatheter be as small as possible; in order to allow the shaped (and in particular the stiffer) CTO guide wire to smoothly enter the lumen of the proximal end of the dual-lumen microcatheter, it is desirable that the lumen of the dual-lumen microcatheter be as large as possible (i.e., the inner diameter be as large as possible). However, the outer diameter of the catheter is necessarily increased while the inner diameter of the lumen is increased, so that the existing double-lumen microcatheter cannot simultaneously meet the requirements of certain pushing strength and smooth entering of a hard CTO guide wire.

Aiming at the problems, the embodiment of the application provides a double-cavity microcatheter which can simultaneously meet the requirements of having certain pushing strength and enabling a hard CTO guide wire to enter smoothly.

The following describes the technical scheme of the embodiments of the present application in detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural view of a dual lumen microcatheter as shown in an embodiment of the present application.

Referring to fig. 1, the dual-lumen microcatheter includes a first tube body 1, the first tube body 1 including a proximal section S1, a middle section S2, and a distal section S3 connected in sequence. The end of the proximal section S1 remote from the intermediate section S2 is connected with a catheter hub 3, and the catheter hub 3 can pass through a guide wire. And part or all of the proximal section S1 is a variable diameter portion B1, and the inner diameter of the variable diameter portion B1 gradually decreases from the proximal end to the distal end. Wherein the proximal section S1 is sleeved with a partial section which is provided with a stress removing pipe and is connected with the catheter seat 3, the distal section S3 is connected with the second catheter body 2 of the double-cavity micro catheter, and the middle section S2 is connected with the proximal section S1 and the distal section S3.

According to the embodiment of the application, part or all of the proximal section S1 forms the reducing part B1 through reducing design, the inner cavity of the proximal end (close to the catheter seat 3) of the reducing part B1 is enlarged, so that a hard CTO guide wire can conveniently and smoothly enter the proximal section S1, a user can select more types of CTO guide wires, and the effect of being compatible with various CTO guide wires is achieved. And the inner diameter of the reducing part B1 gradually decreases from the proximal end to the distal end, so that the proximal end section S1 can be gradually transited to the middle section S2, stress concentration is avoided, and meanwhile, the guide wire entering path is optimized. Further, the distal end of the variable-diameter portion B1 is directly or indirectly connected to the intermediate section S2, that is, the outer diameter of the distal end of the variable-diameter portion B1 must be equal to the outer diameter of the intermediate section S2, enabling the inner diameter to be enlarged without enlarging the outer diameter. Therefore, the double-cavity microcatheter provided by the embodiment of the application can simultaneously meet the requirements of having certain pushing strength and enabling the hard CTO guide wire to enter smoothly.

As an alternative embodiment, see fig. 1 and 2, the outer diameter of the variable diameter portion B1 is kept constant from the proximal end to the distal end, and the outer diameter of the variable diameter portion B1 is equal to the outer diameter of the intermediate section S2.

When the portion of the proximal segment S1 is the variable-diameter portion B1, the variable-diameter portion B1 may or may not be connected to the intermediate segment S2; but the outer diameter of the variable diameter portion B1 is equal to the intermediate section S2. When all of the proximal segment S1 is the variable diameter portion B1, the proximal end of the variable diameter portion B1 is connected to the catheter holder 3, the distal end is connected to the intermediate segment S2, and the outer diameter of the variable diameter portion B1 is also equal to the intermediate segment S2. That is, the variable diameter portion B1 can keep the outer diameter of the proximal section S1 unchanged while enlarging the lumen of the proximal section S1.

Further, as shown in fig. 1 and 2, a part of the proximal section S1 is a diameter-variable portion B1, and the other part is a straight tube portion Z1 connected to the diameter-variable portion B1 in the longitudinal direction of the proximal section S1; the outer diameter of the straight tube portion Z1 is equal to the outer diameter of the variable diameter portion B1. One end of the straight pipe part Z1 far away from the variable diameter part B1 is connected with the catheter seat 3, and one end of the variable diameter part B1 far away from the straight pipe part Z1 is connected with the middle section S2; alternatively, the end of the straight tube portion Z1 remote from the variable diameter portion B1 is connected to the intermediate section S2, and the end of the variable diameter portion B1 remote from the straight tube portion Z1 is connected to the catheter holder 3.

When the variable diameter portion B1 is connected to the intermediate section S2 and the straight tube portion Z1 is connected to the catheter hub 3 in the embodiment of the present application. That is, the proximal end of the variable diameter portion B1, that is, the end having the largest inner diameter is connected to the straight tube portion Z1, and then the inner diameter of the straight tube portion Z1 is equal to the largest inner diameter of the variable diameter portion B1. Not only the inner diameter of the proximal segment S1 is increased, but also the length of the portion having the large inner diameter is prolonged, greatly improving the throughput of the guide wire and the guide wire passing efficiency. And then the distal end of the reducing portion B1, that is, the end with the smallest inner diameter is connected to the intermediate section S2, so that the outer diameter of the reducing portion B1 is ensured to be equal to the outer diameter of the intermediate section S2, and then the outer diameter of the straight tube portion Z1 is also ensured to be equal to the outer diameter of the intermediate section S2. Therefore, the inner diameter of the proximal section S1 is enlarged, and the outer diameter of the proximal section S1 is kept unchanged, so that the pushing strength of the proximal section S1 is kept unchanged.

When the variable diameter portion B1 is connected to the duct base 3 and the straight tube portion Z1 is connected to the intermediate section S2 in the embodiment of the present application. This solution has some drawbacks compared with the previous solution in that the distal end of the variable-diameter portion B1, i.e., the end with the smallest inner diameter, is connected to the straight tube portion Z1, resulting in the advantage that the straight tube portion Z1 cannot realize the enlargement of the lumen.

As an alternative embodiment, referring to fig. 2-4, the proximal segment S1, the intermediate segment S2, and the distal segment S3 each include an inner layer, a braid, and an outer layer disposed in sequence from inside to outside.

Because of the need for flexibility and sizing (or passability) of the distal end of the dual lumen microcatheter of the related art, the distal end is often designed in a dual lumen version of a single or dual layer polymer, and is predominantly of a softer resin material. The relatively stiff and sharp guide wire head end, which is bent at an angle, often causes a puncture in the lumen when passing through the lumen formed by the thin and soft materials, which affects the smooth operation.

Therefore, the inner cavities of the proximal section S1, the middle section S2 and the distal section S3 in the embodiment of the application are all covered with the braiding layers, so that the problem that the shaped harder CTO guide wire punctures the catheter tube is avoided.

Preferably, as shown in fig. 2, when the end of the straight tube portion Z1 away from the variable diameter portion B1 is connected to the catheter hub 3 and the end of the variable diameter portion B1 away from the straight tube portion Z1 is connected to the intermediate section S2, the inner layer, the braid and the outer layer of the proximal section S1 are the first inner layer 10, the first braid 11 and the first outer layer 12, respectively; a first transition cavity 13 is formed between the first inner layer 10 and the first braid 11 of the variable-diameter portion B1, and the first outer layer 12 of the variable-diameter portion B1 penetrates into the first transition cavity 13 through the first braid 11 and is connected to the first inner layer 10.

The first inner layer 10 of the present embodiment may be made of one of polytetrafluoroethylene PTFE, fluorinated ethylene propylene FEP, perfluoroalkoxy alkane PFA, polyethylene terephthalate PET, or polyetheretherketone PEEK. The first braid 11 may be made of metal or fiber. The first outer layer 12 may be made of one of a polyamide material, a polyether block polyamide, a polyurethane material, an elastomer, or a synthetic rubber. The first outer layer 12 may be connected to the outside of the first knitted layer 11 by welding, sleeve welding, thermoplastic or the like, and in the connecting process, the first outer layer 12 may be melted to have fluidity, so as to pass through the knitted mesh of the first knitted layer 11 to be bonded with the first inner layer 10, thereby forming a proximal segment S1 with strong reliability.

Further, since the inner diameter of the variable diameter portion B1 gradually decreases and the outer diameter is equal to the outer diameters of the intermediate section S2 and the straight tube portion Z1, a first transition chamber 13 is formed between the first inner layer 10 and the first braid 11 of the variable diameter portion B1. In the embodiment of the present application, when the diameter-variable portion B1 is formed, the first braid 11 of the straight tube portion Z1 is wound to the diameter-variable portion B1 along the length direction of the proximal end section S1 by braiding wires; the first outer layer 12 of the reducing part B1 penetrates into the first transition cavity 13 through the first woven layer 11 under the extrusion action after being melted until the first transition cavity 13 is filled, and the first outer layer 12 material in the first transition cavity 13 is adhered to the first inner layer 10 to realize the forming of the reducing part B1.

In addition, in order to implement the soft-hard gradual transition between the variable diameter portion B1 and the intermediate section S2 in the embodiment of the present application, the first outer layer 12 material of the variable diameter portion B1 may be selected from harder polymer materials, and the first outer layer 12 material of the specific variable diameter portion B1 may be harder than the first outer layer 12 material of the straight pipe portion Z1 and softer than the second outer layer 23 of the intermediate section S2.

Preferably, as shown in fig. 3, the inner layer, the woven layer and the outer layer of the intermediate section S2 are a second inner layer 20, a second woven layer 22 and a second outer layer 23, respectively, and the second inner layer 20, the second woven layer 22 and the second outer layer 23 are a first inner layer 10, a first woven layer 11 and a first outer layer 12, respectively, which are formed extending to the intermediate section S2; and the intermediate section S2 further comprises a second spring layer 21, the second spring layer 21 being provided between the second inner layer 20 and the second braid 22.

The second spring layer 21 may be made of metal, such as stainless steel. The intermediate section S2 can obtain a sufficient supporting force by the second spring layer 21, so that pushability of the microcatheter can be improved. The second braid 22 is braided outside the second spring layer 21. Even if continuous torque input is performed from the outside, the second spring layer 21 is not scattered due to the protection of the second braid 22 on the outside, and thus the reliability of the microcatheter can be improved.

The embodiment of the application realizes that the inner cavity is enlarged and the outer diameter is not increased by removing the spring layer of the proximal section S1, namely reducing the tube thickness of the proximal section S1.

Still further, referring to fig. 2, the second spring layer 21 does not extend into the first transition chamber 13.

The proximal segment S1 does not have a spring layer, which increases the toughness of the proximal segment S1 and improves the buckling resistance of the proximal segment S1. And the diameter of the diameter-changing part B1 can be smoothly changed; while increasing pushability and lumen retention of the proximal segment S1.

Further, as seen in fig. 4, the inner, braid and outer layers of distal segment S3 are a third inner layer 30, a third braid 31 and a third outer layer 32, respectively; and third inner layer 30, third braid 31 and third outer layer 32 are formed by extending second inner layer 20, second braid 22 and second outer layer 23, respectively, to distal section S3 with a second transition cavity 33 formed between third inner layer 30 and third braid 31, third outer layer 32 penetrating through third braid 31 into second transition cavity 33 and being joined to third inner layer 30.

Since the distal section S3 has one less spring layer than the intermediate section S2, in order to equalize the tube thickness of the distal section S3 with the tube thickness of the intermediate section S2, the thickness of the third outer layer 32 of the distal section S3 is increased so that the third outer layer 32 fills the second transition chamber 33 and is connected to the third inner layer 30. The smoothness and consistency of the inner cavity and the outer cavity of the first pipe body 1 are ensured.

Still further, referring to fig. 4, the second spring layer 21 does not extend into the second transition chamber 33.

The spring layer of the embodiment of the application only covers the middle section S2, so that the whole microcatheter gradually transits from the harder proximal end to the softer distal end, and the pushing performance (the capability of transmitting finger force from the proximal end to the distal end) and the compliance (the capability of the microcatheter to bend along the blood vessel) of the distal end of the microcatheter are met.

Optionally, referring to fig. 4, the dual-lumen microcatheter further includes a second tube body 2 connected to the distal segment S3, the second tube body 2 including a fourth inner layer 40 and a fourth outer layer 41 sequentially connected from inside to outside, the fourth outer layer 41 being connected to an outer surface of the distal segment S3.

The fourth inner layer 40 and the fourth outer layer 41 of the present embodiment may be made of the same material or different materials. The fourth inner layer 40 may be made of one of polytetrafluoroethylene PTFE, fluorinated ethylene propylene FEP, perfluoroalkoxy alkane PFA, polyethylene terephthalate PET, or polyetheretherketone PEEK. The fourth outer layer 41 may be made of one of a polyamide material, a polyether block polyamide, a polyurethane material, an elastomer, or a synthetic rubber.

As another alternative embodiment, see fig. 5, the outer diameter of the variable diameter portion B1 gradually decreases from the proximal end to the distal end, and the outer diameter of the distal end of the variable diameter portion B1 is equal to the outer diameter of the intermediate section B2.

In this case, the proximal end of the variable diameter portion B1 is connected to the catheter hub 3, the distal end is directly or indirectly connected to the intermediate section S2, and only the outer diameter of the distal end of the variable diameter portion B1 is equal to the intermediate section S2.

Further, as shown in fig. 6, a part of the proximal section S1 is a diameter-variable portion B1, and the other part is a straight tube portion Z1; the straight tube portion Z1 has an outer diameter equal to the outer diameter of the distal end of the variable diameter portion B1. One end of the straight tube part Z1 is connected with the variable-diameter part B1 in the length direction of the proximal section S1, the other end of the straight tube part Z1 is connected with the middle section S2, and the outer diameters of the straight tube part Z1 and the middle section S2 are equal; the end of the variable diameter portion B1 remote from the straight tube portion Z1 is connected to the catheter hub 3.

In this case, the variable diameter portion B1 and the straight tube portion Z1 are not integrally formed, and the materials used for the variable diameter portion B1 and the straight tube portion Z1 are also different. The variable diameter portion B1 is responsible for enlarging the lumen of the proximal section S1, and the straight tube portion Z1 is responsible for not enlarging the outer diameter of the proximal section S1.

Further, the thickness of the variable diameter portion B1 is equal to the thickness of the straight tube portion Z1. The transition between the reducing part B1 and the straight pipe part Z1 is more gentle, and the compliance of the reducing part B1 and the inner cavity and the outer surface of the straight pipe part Z1 is ensured.

Further, the diameter-variable portion B1 is made of a ductile resin, such as a polyurethane material. To increase the bending resistance of the proximal segment S1.

As an alternative embodiment, referring to fig. 3, 4 and 6, the straight tube portion Z1, the intermediate section S2 and the distal section S3 each include an inner layer, a braid and an outer layer disposed in that order from inside to outside.

The inner cavities of the proximal section S1, the middle section S2 and the distal section S3 are all covered with the braiding layers, so that the problem that the catheter tube body is punctured by the shaped harder CTO guide wire is avoided.

Further, the inner layer, the braid and the outer layer of the straight tube portion Z1 are the first inner layer 10, the first braid 11 and the first outer layer 12, respectively; and the straight tube portion further comprises a first spring layer 14 provided between the first inner layer 10 and the first braid 11. The inner layer, the woven layer and the outer layer of the middle section S2 are a second inner layer 20, a second spring layer 21, a second woven layer 22 and a second outer layer 23, respectively; and the second inner layer 20, the second spring layer 21, the second braid 22 and the second outer layer 23 are formed with the first inner layer 10, the first spring layer 14, the first braid 11 and the first outer layer 12 extending to the intermediate section S2, respectively.

The first and second inner layers 10 and 20 of the embodiments of the present application may be made of one of polytetrafluoroethylene PTFE, fluorinated ethylene propylene FEP, perfluoroalkoxyalkane PFA, polyethylene terephthalate PET, or polyetheretherketone PEEK. The first spring layer 14 and the second spring layer 21 may be made of metal, such as stainless steel. The first and second braid 11 and 22 may be made of metal or fiber. The first outer layer 12 and the second outer layer 23 may be made of one of a polyamide material, a polyether block polyamide, a polyurethane material, an elastomer, or a synthetic rubber.

Further, the inner, braid and outer layers of distal segment S3 are a third inner layer 30, a third braid 31 and a third outer layer 32, respectively; and third inner layer 30, third braid 31 and third outer layer 32 are formed by extending second inner layer 20, second braid 22 and second outer layer 23, respectively, to distal section S3 with a second transition cavity 33 formed between third inner layer 30 and third braid 31, third outer layer 32 penetrating through third braid 31 into second transition cavity 33 and being joined to third inner layer 30.

The distal segment S3 of the present embodiment does not have a spring layer, so that the microcatheter gradually transitions from a stiffer proximal end to a softer distal end as a whole, meeting the pushability (the ability to transfer finger force from proximal end to distal end) and compliance (the ability of the microcatheter to conform to the curvature of the vessel) requirements of the microcatheter into the distal end of the vessel.

The aspects of the present application have been described in detail hereinabove with reference to the accompanying drawings. In the foregoing embodiments, the descriptions of the embodiments are focused on, and for those portions of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments. Those skilled in the art will also appreciate that the acts and modules referred to in the specification are not necessarily required in the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application may be sequentially adjusted, combined and pruned according to actual needs, and the modules in the apparatus of the embodiment of the present application may be combined, divided and pruned according to actual needs.

The embodiments of the present application have been described above, the foregoing description is exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. The double-cavity microcatheter is characterized by comprising a first tube body, wherein the first tube body comprises a proximal end section, a middle section and a distal end section which are sequentially connected; part or all of the proximal section is a variable diameter portion, the inner diameter of which gradually decreases from the proximal end to the distal end.

2. The dual lumen microcatheter of claim 1, wherein the outer diameter of the reduced diameter portion remains constant from the proximal end to the distal end and the outer diameter of the reduced diameter portion is equal to the outer diameter of the intermediate section.

3. The dual lumen microcatheter of claim 2 wherein:

4. The dual lumen microcatheter of claim 3, wherein the proximal section, the middle section, and the distal section each comprise an inner layer, a braid, and an outer layer disposed in sequence from inside to outside.

5. The dual lumen microcatheter of claim 4 wherein the inner layer, braid and outer layer of the proximal section are a first inner layer, a first braid and a first outer layer, respectively, when the end of the straight tube portion distal from the reduced portion is connected to the catheter hub and the end of the reduced portion distal from the straight tube portion is connected to the intermediate section; a first transition cavity is formed between the first inner layer and the first braiding layer of the reducing part, and the first outer layer of the reducing part penetrates into the first transition cavity through the first braiding layer and is connected with the first inner layer.

6. The dual lumen microcatheter of claim 5, wherein the inner, woven and outer layers of the intermediate section are a second inner, a second woven and a second outer layer, respectively, the second inner, second woven and second outer layers being formed by the first inner, first woven and first outer layers, respectively, extending to the intermediate section; and the middle section further comprises a second spring layer, wherein the second spring layer is arranged between the second inner layer and the second braiding layer.

7. The dual lumen microcatheter of claim 6, wherein the second spring layer does not extend into the first transition lumen.

8. The dual lumen microcatheter of claim 6, wherein the inner layer, the braid, and the outer layer of the distal section are a third inner layer, a third braid, and a third outer layer, respectively; and the third inner layer, the third braiding layer and the third outer layer are respectively formed by extending the second inner layer, the second braiding layer and the second outer layer to the distal end section, a second transition cavity is formed between the third inner layer and the third braiding layer, and the third outer layer penetrates into the second transition cavity through the third braiding layer and is connected with the third inner layer.

9. The dual lumen microcatheter of claim 8, wherein the second spring layer does not extend into the second transition lumen.

10. The dual lumen microcatheter of claim 1 further comprising a second tube connected to the distal section, the second tube comprising a fourth inner layer and a fourth outer layer connected in sequence from inside to outside, the fourth outer layer being connected to an outer surface of the distal section.

11. The dual lumen microcatheter of claim 1, wherein the outer diameter of the reduced diameter portion tapers from the proximal end to the distal end and the outer diameter of the reduced diameter portion distal end is equal to the outer diameter of the intermediate section.

12. The dual lumen microcatheter of claim 11 wherein:

13. The dual lumen microcatheter of claim 12, wherein the thickness of the reduced diameter portion is equal to the thickness of the straight tube portion; and/or the reducing part is made of ductile resin.

14. The dual lumen microcatheter of claim 12, wherein the straight tube portion, the intermediate section, and the distal section each comprise an inner layer, a braid, and an outer layer disposed in sequence from inside to outside.

15. The dual lumen microcatheter of claim 14, wherein the inner layer, the braid and the outer layer of the straight tube portion are a first inner layer, a first braid and a first outer layer, respectively; and the straight tube portion further includes a first spring layer disposed between the first inner layer and the first braid.

16. The dual lumen microcatheter of claim 15, wherein the inner layer, the braid and the outer layer of the intermediate section are a second inner layer, a second braid and a second outer layer, respectively; the intermediate section further includes a second spring layer disposed between the second inner layer and the second braid; and the second inner layer, the second spring layer, the second woven layer and the second outer layer are formed by extending the first inner layer, the first spring layer, the first woven layer and the first outer layer to the middle section respectively.