CN110639114A

CN110639114A - Catheter tube

Info

Publication number: CN110639114A
Application number: CN201810677229.7A
Authority: CN
Inventors: 肖本好; 唐江峰
Original assignee: Lifetech Scientific Shenzhen Co Ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2018-06-27
Filing date: 2018-06-27
Publication date: 2020-01-03
Anticipated expiration: 2038-06-27
Also published as: CN110639114B

Abstract

The invention discloses a catheter which comprises a main body part and a developing part, wherein the developing part is arranged at the far end of the main body part, the main body part comprises a latticed middle layer, the far end of the middle layer is of a closed structure, and the projection of the developing part and the projection of the middle layer on the cross section where the longitudinal central axis of the catheter is located are not overlapped. The catheter of the invention can solve the problem of 'loose yarn' of the braided yarn in the prior art, improve the quality of the catheter and ensure the use safety of the catheter.

Description

Catheter tube

Technical Field

The invention relates to the field of interventional medicine, in particular to a catheter.

Background

The interventional medical operation has the advantages of small wound, quick recovery, less complication, good treatment effect and the like when used for treating cardiovascular diseases. The implant is delivered to the designated lesion site after transfixion through the femoral or carotid artery by compressing the implant into a catheter, and then pushed to release. This type of delivery device requires that the catheter have good resistance to bending, twisting and pushing, and that the diameter of the catheter be as small as possible to facilitate delivery in smaller vessels.

At present, the guide pipe of the intervention type conveyor is mostly made of composite materials and is divided into an inner layer structure, a middle layer structure and an outer layer structure, wherein the inner layer structure and the outer layer structure are pipe bodies made of high polymer materials, the middle layer structure is a woven net pipe woven by metal wires, and the three layer structure is formed into a whole by hot melting to form the guide pipe. The mesh tube in the middle layer is woven by a weaving machine. In the process of manufacturing the catheter, a section of woven mesh tube is cut and tightened and is attached to the outer surface of the inner tube of the catheter, then the outer tube of the catheter is sleeved, and hot melting forming is carried out to form an integral lumen structure. Because the woven mesh pipe in the catheter is a section cut from the complete woven mesh pipe, the head end of the woven mesh pipe can generate 'loose wires', namely the head end of the metal wire is scattered, and the woven metal wire can be exposed at the outer edge of the catheter after the catheter is subjected to hot melting, so that the quality of the catheter is influenced.

Disclosure of Invention

Based on the defects of the prior art, the invention provides a catheter, which solves the problem of loose filaments of woven filaments in the middle layer of the catheter.

The catheter comprises a main body part and a developing part, wherein the developing part is arranged at the far end of the main body part, the main body part comprises a latticed middle layer, the far end of the middle layer is of a closed structure, and the projection of the developing part and the projection of the middle layer on the cross section where the longitudinal central axis of the catheter is located are not overlapped.

In one embodiment, the distal side of the intermediate layer comprises at least one bend comprising a first apex, the distal end of the intermediate layer being formed by the first apex of the at least one bend.

In an embodiment, the intermediate layer further comprises at least one second apex, the at least one second apex is circumferentially spaced from the at least one first apex, and the at least one first apex is on a first cross-section of the conduit, and a plurality of the second apexes are on a second cross-section of the conduit.

In one embodiment, at least one of said first apices of said intermediate layer is at a distance from the longitudinal central axis of said conduit that is less than the distance from any of said second apices to the longitudinal central axis of said conduit.

In one embodiment, the proximal end of the developing portion is provided with at least one notch for receiving at least one of the first vertices.

In one embodiment, the notch is a V-shaped notch, a U-shaped notch, an arc-shaped notch or a trapezoid notch with the opening facing the proximal end.

In one embodiment, the bending angle of the bending section is larger than the opening angle of the V-shaped notch.

In one embodiment, the intermediate layer includes a plurality of braided wires having free ends at distal ends thereof, and a receptacle provided at the distal ends of the braided wires, the receptacle being connected to the free ends of the distal ends of the braided wires.

In one embodiment, the proximal end of the receiving member is provided with a receiving groove for receiving the free end of the knitting yarn.

In an embodiment, a maximum radial thickness of the developing portion is less than or equal to a maximum radial thickness of the intermediate layer.

The far end of the middle layer of the catheter main body part is of a closed structure, so that the problem of 'loose yarn' of braided yarn after the catheter is formed in the prior art is solved, the quality of the catheter is improved, and the use safety of the catheter is ensured.

Drawings

FIG. 1 is a schematic cross-sectional view of a catheter structure of the present invention;

FIG. 2 is a schematic view of the structure of a catheter according to example 1 of the present invention, in which the outer layer is not shown;

FIG. 3 is a schematic view of the structure of a catheter according to example 2 of the present invention, wherein the outer layer is not shown;

FIG. 4 is a schematic view of the structure of a catheter according to example 3 of the present invention, in which the outer layer is not shown;

FIG. 5 is an enlarged view of a portion of the structure of FIG. 4;

FIG. 6 is a schematic view of the structure of a catheter according to example 4 of the present invention, in which the outer layer is not shown;

FIG. 7 is a schematic view of the receptacle of FIG. 6;

fig. 8 is an enlarged view of a portion of the structure of fig. 7.

Detailed Description

For a better understanding of the present invention, the present invention is further described in detail with reference to the following specific examples.

In the field of interventional medicine, the end closer to the operator is defined as "proximal" and the end further from the operator as "distal".

Example 1

As shown in FIG. 1, the catheter 10 is an elongated hollow tubular structure having a longitudinal central axis extending along its length. The catheter 10 includes a main body portion 11 and a visualization portion 12 provided at a distal end of the main body portion. The main body 11 includes an inner layer 111 having a hollow tubular shape, an intermediate layer 112 covering the inner layer 111, and an outer layer 113 covering the intermediate layer 112, which are sequentially disposed from the inside to the outside. The inner layer 111 and the outer layer 113 are both made of a polymer material, in this example PEBAX. In other embodiments, the inner and outer layers may be made of the same material or different materials, such as nylon, PTFE, or polyester.

The intermediate layer 112 may be formed by a plurality of braided filaments 114 that are interwoven such that the distal ends thereof are closed structures rather than the free ends of the braided filaments 114 being "loose" in shape. The "distal end of the intermediate layer is in a closed structure" in the present invention means that the distal end of the intermediate layer is in a structure other than a scattered non-closed structure in which the distal end of the intermediate layer is formed by the free ends of the plurality of braided wires (i.e., the free ends of the plurality of braided wires in the non-closed structure are relatively free open structures). It will be appreciated that in other embodiments, the intermediate layer may also be a grid-like structure formed in other ways, such as by cutting a metal tube. Specifically, braided wires 114 of the present embodiment are stainless steel wires. Referring to fig. 2, the braided wires 114 are formed with a bending section 115 opening toward the proximal end on the distal side of the intermediate layer 112, and the distal end of the bending section 115 includes an apex 116, and the apices defining the distal ends of two adjacent braided wires 114 are a first apex 116a and a second apex 116b, respectively. The first and second apexes 116a and 116b are spaced apart in the circumferential direction of the intermediate layer 112. In this manner, the plurality of apexes 116 of the plurality of braided wires 114 are spaced apart in the circumferential direction of the intermediate layer 112. Preferably, all of the first apex 116a and the second apex 116b in this embodiment are on the same cross-section of the catheter 10 perpendicular to the longitudinal central axis. A bend segment 115 having an apex 116 is formed by bending a single braided wire 114. The bending angle theta of the bending section 115 can be selected and determined according to actual requirements, when the bending angle is too large, the woven wire mesh is too sparse, the bending resistance of the catheter is poor, otherwise, when the bending angle is too small, the woven wire mesh is too dense, the whole catheter is hard, and the flexibility is poor. Therefore, to balance the bending resistance and compliance of the catheter, it is desirable to approximate the catheter mesh to a regular diamond shape, so the bending angle θ may range from 60 degrees to 120 degrees.

The intermediate layer 112 is a mesh structure formed by weaving monofilaments. The monofilament knitting means that one knitting yarn 114 of the knitting yarns 114 is bent to form two single-strand knitting yarns, and each single-strand knitting yarn is knitted together with one single-strand knitting yarn of the two single-strand knitting yarns formed by bending an adjacent knitting yarn. Thus, the maximum radial thickness of the intermediate layer 112 is defined by the diameter of the two braided wires 114

And (5) determining superposition. To further ensure the maximum diameter of the main body 11 of the catheter 10And the diameter of the developing part 12

Equally, the maximum radial thickness h of the development part 12 should correspond to the thickness of the intermediate layer 112, i.e.It can be understood that, in other embodiments, the maximum radial thickness of the developing part may also be smaller than the maximum radial thickness of the intermediate layer, at this time, the maximum diameter of the catheter at the developing part is smaller than the maximum diameter of the main body part, and still the maximum outer diameter of the catheter cannot be increased due to the addition of the developing part, and when the catheter is used, the distal end of the catheter with the smaller maximum diameter of the developing part enters into the body first, the transition is smooth, the catheter is easier to penetrate, and the injury to the human body is small.

The developing unit 12 has a ring-shaped structure and is provided between the inner layer 111 and the outer layer 113. Developing part 12 and intermediate layer 112 are juxtaposed outside inner layer 111 without overlapping, i.e., the projection of developing part 12 onto the cross-section of catheter 10 where the longitudinal center axis lies does not overlap the projection of intermediate layer 112 onto that plane. Meanwhile, a certain gap W exists between the distal end of the developing part 12 and the distal end of the inner layer 111 in a direction parallel to the longitudinal central axis of the catheter 10, so that the outer layer 113 can be closely attached to the inner layer 111 after the heat-melting process. In order to prevent the developing unit 12 from being exposed, falling off due to an excessively small gap W or being turned inside out and warped at the distal end of the catheter 10 during assembly due to an excessively large gap W, the length of W is preferably about 1 mm to 3 mm.

There is a distance S1 between the proximal end of the visualization portion 12 and the distal end of the intermediate layer 112 in a direction parallel to the longitudinal center axis of the catheter 10. In order to ensure good pushing performance and bending resistance of the catheter, the distance S1 should be within a reasonable range. If the distance S1 is too large, the outer layer 113 of the catheter 10 is likely to bulge and form wrinkles between the proximal end of the developing part 12 and the intermediate layer 112 during the pushing process, which makes the pushing of the catheter 10 difficult; if the distance S1 is too small, the vertex 116 and the developing part 12 are easily pressed against each other and are in single-point contact with each other during the pushing process, and the knitting yarn 114 is soft, which may cause the distal end of the intermediate layer 112 to be entirely expanded and even to be sleeved on the developing part 12, thereby damaging the catheter 10. Therefore, the distance S1 needs to satisfy the following condition:

where S2 is the average distance between axially adjacent intersections of braided filaments 114 on intermediate layer 112. S2 is determined by the mesh density of the braided filaments 114, which is determined by the outer diameter of the intermediate layer 112

The number of strands n of the braided wire, the angle theta of the bending section 115. The braided wire 114 of the catheter 10 of the present embodiment is uniformly braided, that is, the braided wire 114 is uniformly distributed outside the inner layer 111, and the number of braided wire strands is not too large or too small, so that the flexibility of the whole catheter is poor due to too large number of braided wire strands, and the bending resistance of the whole catheter is poor due to too small number of braided wire strands. Therefore, the number of strands of the braided wire may preferably be 12 to 16 strands. S2 can be represented by the following formula:

therefore, the distance S1 should satisfy the following condition:

the developing portion 12 is a developing material that can be developed under the image forming apparatus, and may be selected from a noble metal material or an alloy material, such as platinum-iridium alloy of the present embodiment. The visualization portion 12 may display the specific position of the catheter 10 with the aid of an imaging device after the catheter 10 has been introduced into the body. In order to provide the conduit 10 with good developability without affecting the overall performance of the conduit 10, the width W0 of the development section 12 (i.e., the length of the development section 12 in a direction parallel to the longitudinal center axis of the conduit 10) of the conduit 10 of the present invention is preferably not too small or too large. If the developing part is too small, the catheter is poor in developability, and if the developing part is too large, the distal end of the catheter is too hard, and the blood vessel may be damaged during use. Therefore, the width W0 of the developing portion may be selected to be 3 to 4 mm.

The distal end of the middle layer of the catheter is of a closed structure, the free end of the braided wire does not exist, the exposed situation of the braided wire after the catheter is formed is avoided, and the risk of damage of the catheter in the use process is reduced. Meanwhile, the catheter developing part and the catheter intermediate layer are not overlapped in the radial direction, and the maximum radial thickness of the developing part is not larger than that of the intermediate layer, so that the catheter has developing performance after being introduced into the developing part, but the maximum outer diameter is not increased, the catheter can adapt to small-diameter blood vessels, and the pushing performance of the catheter is improved.

Example 2

As shown in fig. 3, the catheter 20 of the present embodiment has substantially the same structure as the catheter 10 of embodiment 1, except that: first, the distal end of the intermediate layer 212 of the catheter 20 of the present embodiment has a slight radial constriction towards the inner layer 211; second, the first apex 216a and the second apex 216b of the catheter 20 of the present embodiment are spaced apart by a distance S4 in a direction parallel to the longitudinal central axis of the catheter 20, i.e., the plurality of apices 216 distal of the intermediate layer 212 are not flush.

The radial constriction of the distal end of the intermediate layer 212 towards the inner layer 211 is formed by the plurality of first apices 216a being closer to the outer surface of the inner layer 211, i.e., the plurality of first apices 216a are radially closer to the outer surface of the inner layer 211 than the remainder of the intermediate layer 212. Second apices 216b may be located as close to the outer surface of inner layer 211 as first apices 216a, but first apices 216a are located closer to the outer surface of inner layer 211 than second apices 216b, i.e., the distance from first apices 216a to the longitudinal central axis of conduit 20 is less than the distance from either of second apices 216b to the longitudinal central axis of conduit 20. Therefore, compared to example 1, the configuration in which the distal end of the intermediate layer 212 is provided with a radial constriction allows the distal end of the intermediate layer 212 to be pressed against the outer surface of the inner layer 211 with an appropriate force, resulting in a stronger adhesion between the intermediate layer 212 and the inner layer 211. It will be appreciated that in other embodiments, the second apices may also be disposed in a configuration that is not adjacent to the outer surface of the inner layer.

The plurality of first apices 216a are on a first cross-section of the conduit 20 perpendicular to the longitudinal central axis of the conduit 20, the plurality of second apices 216b are on a second cross-section of the conduit 20 perpendicular to the longitudinal central axis of the conduit 20, and the first cross-section and the second cross-section are not the same cross-section. I.e., the first apex 216a and the second apex 216b are not equidistant from the proximal end of the imaging portion 22 in a direction parallel to the longitudinal central axis of the catheter 20. Wherein a distance S3 in a direction parallel to the longitudinal central axis of the conduit 20 between the first apex 216a and the developing part 22 is the same as S1 in the first embodiment. The axial spacing S4 between the first apex 216a and the second apex 216b is selected to be appropriate, and if S4 is too large, a larger area of non-woven filament support will occur at the distal end of the intermediate layer 212, and the overall support performance of the catheter 20 will be reduced; if S4 is too small, when second vertex 216b is also disposed toward the outer surface of inner layer 211 as with first vertex 216a, inner layer 211 tends to be partially recessed in a full circle due to the resultant force of the plurality of vertices 216. Therefore, S4 needs to satisfy the following condition:

wherein S5 is the average distance between axially adjacent intersections of the braided filaments on the intermediate layer 212, and the determination method is the same as that in embodiment 1, and is not described herein again.

It is understood that in other embodiments, the first vertex and the second vertex may not be disposed adjacent to each other in sequence, that is, a plurality of first vertices may be disposed continuously in the circumferential direction of the catheter, and then at least one second vertex may be disposed, or vice versa. Further, in other embodiments, the first vertex and the second vertex may be disposed non-uniformly.

Example 3

Referring to fig. 4 and 5, the catheter 30 of the present embodiment is substantially the same in structure as the catheter 10 of embodiment 1, except that: the proximal end of the developing part 32 of the present embodiment is provided with a plurality of notches 321 corresponding to the plurality of vertices 316 at the distal end of the intermediate layer 312, and the number of the notches 321 is the same as the number of the vertices 316. It will be appreciated that in other embodiments, the number of notches may also be less than the number of vertices, i.e., one notch may receive more than one vertex.

The notch 321 is a V-shaped notch with an opening facing the proximal end, and is opened on the proximal end edge of the developing part 32, and can receive the bending section 315 of the intermediate layer 312, and the opening angle α of the notch 321 is smaller than the bending angle β of the bending section 315. Thus, the notch of the developing portion 32 can be brought into two-point contact (i.e., points B and C in fig. 5) with the intermediate layer 312, instead of one-point contact (i.e., point a in fig. 5). According to the vector superposition of the forces and the parallelogram rule, when the same magnitude of force is applied, the resultant force of the reaction forces of the points B and C is greater than the reaction force of the point A, so that the structure can provide larger axial force. Meanwhile, the middle layer 312 of the catheter 30 can be in multi-point contact with the developing part 32, so that the torsion resistance and the pushing performance of the whole catheter 30 are improved. In order not to degrade the developing performance of the developing portion 32, the depth S6 of the notch 312 should satisfy the following relationship:

w1 represents the axial width of the developing section 32, and S7 represents the average distance between axially adjacent intersections of the braided wires in the intermediate layer 312, and the determination is performed in the same manner as in example 1, and will not be described again.

It will be appreciated that in other embodiments the distal apex of the intermediate layer may be the weld at the free ends of the two braided wires, and that the weld is flattened to ensure that the thickness of the weld is less than or equal to the radial thickness of the developer portion, and that the weld may be curved towards the inner layer of the catheter to abut the outer surface of the inner layer.

It will be appreciated that in other embodiments, the notch may have other shapes, such as an arc, U-shape, trapezoid, etc., so long as it is ensured that the notch does not make a single point contact with the distal end of the intermediate layer.

Example 4

Referring to fig. 6 to 8, the catheter 40 of the present embodiment is substantially the same in structure as the catheter 10 of embodiment 1, except that: first, the distal ends of the braided filaments 414 of the intermediate layer 412 are free ends; second, the distal end of the intermediate layer 412 also includes a receptacle 417 that receives the distal end of the braided wire 414.

The receiving member 417 is annular and is provided between the distal end of the braided wire 414 and the proximal end of the developing unit 42, and receives the distal end of the braided wire 414. The width W3 of receptacle 417 should not be too wide, otherwise the distal end of catheter 30 would be cumbersome and too narrow, otherwise the braided wire 414 would tend to fall out. Therefore, the width W3 of the container piece 417 should be smaller than the width W2 of the developing portion 42 but larger than half of W2.

A plurality of receiving grooves 418 are provided on the proximal end side of the receiving member 417, the receiving grooves 418 are formed by partially recessing the proximal end surface of the receiving member 417 toward the distal end of the receiving member 417, and the receiving grooves 418 penetrate the outer surface of the receiving member 417. The width t of the receiving groove 418 along the circumferential direction of the receiving member 417 is slightly larger than the diameter of the weaving wire 414, and is about 1.2 times of the diameter of the weaving wire 414; the radial depth H of the accommodating groove 418 is larger than the diameter of the weaving wire 414, so that the weaving wire 414 is completely embedded into the accommodating groove and does not fall off from the accommodating groove; the axial depth W4 of the receiving groove 418 should be less than the width W3 of the receiving piece 417 and not less than half of W3. The distal end of the braided wire 414 is preferably substantially received in the receiving groove 418 to a depth that preferably corresponds to the axial depth W4 of the receiving groove 418. After the braided wire 414 is inserted into the receiving groove 418, the two can be further firmly bonded by using an adhesive, the adhesive can be organic glue or can be connected by welding, and in this case, the receiving member is preferably made of the same material as the braided wire.

Since the developing part 42 and the housing member 417 of the present embodiment are both annular, surface contact between the two can be achieved more easily, which can ensure better pushing performance of the conduit.

It will be appreciated that in other embodiments, the receiving recess may have other configurations, such as a recess formed in the proximal end of the receiving member. Furthermore, in other embodiments, the receiving member may not have a receiving groove, and in this case, the free end of the knitting yarn and the receiving member may be directly connected by welding or bonding.

The above embodiments are only for explaining the technical solutions of the present invention, and do not limit the present invention, and those skilled in the art may combine and replace some of the structures in the above embodiments according to actual needs, and the description will not exemplify various possible combinations. The protection scope of the invention is subject to the claims.

Claims

1. The utility model provides a catheter, includes main part and development portion, development portion locates the main part distal end, the main part is including being latticed intermediate level, its characterized in that, the intermediate level distal end is the closed structure, development portion with the intermediate level is in projection on the cross-section at the longitudinal central axis place of catheter does not overlap.

2. The catheter of claim 1, wherein the distal side of the intermediate layer comprises at least one bend comprising a first apex, the distal end of the intermediate layer being comprised of the first apex of the at least one bend.

3. The conduit according to claim 2, wherein the intermediate layer further comprises at least one second apex spaced circumferentially from the at least one first apex on a first cross-section of the conduit, and a plurality of the second apexes on a second cross-section of the conduit.

4. A catheter according to claim 3, wherein at least one of said first apices of said intermediate layer is spaced less from a longitudinal central axis of said catheter than any of said second apices.

5. The catheter of claim 2, wherein the visualization portion proximal end is provided with at least one notch for receiving at least one of the first vertices.

6. The catheter of claim 5, wherein the notch is a V-shaped notch, a U-shaped notch, an arc-shaped notch, or a trapezoidal notch opening toward the proximal end.

7. The catheter of claim 6, wherein the bend angle of the bend section is greater than the opening angle of the V-notch.

8. The catheter of claim 1, wherein the intermediate layer comprises a plurality of braided wires having free ends at distal ends thereof and a receptacle disposed at the distal ends of the braided wires, the receptacle being connected to the free ends of the distal ends of the braided wires.

9. A catheter according to claim 8, wherein the proximal side of the receiving member is provided with a receiving groove for receiving the free end of the braided wire.

10. The catheter according to any one of claims 1 to 9, wherein a maximum radial thickness of the developing portion is less than or equal to a maximum radial thickness of the intermediate layer.