CN112057677A

CN112057677A - Medical catheter made of composite material

Info

Publication number: CN112057677A
Application number: CN201910501735.5A
Authority: CN
Inventors: 尤东侠
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-06-11
Filing date: 2019-06-11
Publication date: 2020-12-11

Abstract

The invention discloses a medical catheter made of composite materials, which comprises a catheter proximal end, a catheter main body and a catheter distal end flexible section, wherein each section of the catheter consists of an outermost layer, a secondary outer layer, an intermediate layer and a smooth inner layer; the outermost layer is made of nylon or block polyether amide elastomer Pebax or polyester polyurethane; the secondary outer layer material is polyether polyurethane; the middle layer is one or more sections of metal woven meshes or metal spring meshes; the inner layer is made of Polytetrafluoroethylene (PTFE), or high-density polyethylene (HDPE), or block polyether amide elastomer (Pebax) containing a friction coefficient reducing additive. The composite material catheter has the advantages that the distal end of the catheter is more flexible, the stretchability resistance and the durability are good, the inner PTFE layer of the catheter is more tightly combined with the outer PTFE layer of the catheter, the safety of the catheter is improved, the trafficability characteristic, the bending resistance and the control performance are superior, the catheter can be pushed to more distal and finer blood vessels, and the success rate of the operation is high.

Description

Medical catheter made of composite material

Technical Field

The invention relates to a medical catheter, and belongs to the technical field of medical instruments.

Background

The medical catheter is a general term for lumen products communicating the inside and outside of a human body and can be made of different materials such as metal, plastic, rubber and the like. Are widely used as a passage for interventional operations, drainage, administration, blood transfer, and the auxiliary introduction of other medical instruments. The conventional vascular interventional catheter has a three-layer structure: polymer plastic outer layer, metal mesh grid intermediate level and PTFE inlayer. The principle is that a metal mesh grid with high mechanical property is embedded between a high polymer plastic outer layer and a PTFE inner layer through special heat treatment. Under the condition of the same wall thickness, the axial and radial mechanical properties of the catheter with the metal mesh grid are improved compared with those of a common plastic catheter. More preferably, the catheter is composed of a plurality of sections of polymer tubes, wherein a material with high hardness is used as the proximal end of the catheter, and a material with low hardness and good flexibility is used as the distal end of the catheter. The catheter with the structure can provide good pushing performance, and meanwhile, the flexible catheter has small damage to the blood vessel at the far end and is easy to pass through tortuous blood vessels. However, the catheter with the metal mesh grid is not perfect, and has the following defects:

1) polytetrafluoroethylene PTFE has a very low coefficient of friction and is not fused to most polymeric plastics, and is commonly referred to as a "non-stick layer". The most commonly used materials of the outer layer of the vessel interventional catheter, such as nylon and block polyether amide elastomer Pebax, are poorly bonded with PTFE, when devices such as stents and the like pass through the inner cavity of the vessel interventional catheter (released and recovered), the condition that the inner layer of the PTFE at the far end or the near end of the vessel is easily stripped by external force occurs, and the stripped PTFE material can generate thrombus when flowing to a far end vessel, so that vessel embolism can be caused when the separated PTFE material seriously, and even the life of a patient is threatened.

2) Materials that are flexible generally have poor axial stretch resistance and durability, and once the distal end of the catheter is campton in a tortuous vessel, the catheter that is not flexible tends to stretch and deform during withdrawal, resulting in failure of the procedure. On the other hand, when a patient has a plurality of lesions in a certain blood vessel to be treated, the durability is so poor that the distal end of the catheter is easily deformed, and the replacement of a new catheter greatly prolongs the operation time and increases the medical cost.

3) Materials that are stretch resistant and durable are often not sufficiently elastic to be compliant, making it difficult for such materials to pass through tortuous vessels as the outer layer of a catheter.

4) When a blood vessel is intervened, particularly when a cerebral blood vessel is intervened, the far-end catheter is required to be very soft, and at the moment, the metal reinforcing mesh of the far-end middle layer is important for the hardness of the far-end catheter. The hardness of the metal net is mainly determined by the diameter or thickness of the metal wire, and the use of the metal wire with smaller diameter or smaller wall thickness can reduce the hardness of the distal catheter, thereby reducing the damage to the blood vessel. However, the metal mesh made of metal wires with smaller diameter or smaller wall thickness has low rigidity, which reduces the pushing performance of the catheter and is not beneficial to the operation.

In contrast, polyurethane materials are easier to bond with PTFE than nylon and Pebax and are more suitable for use at the distal and proximal ends of the catheter, and it is preferred to place a layer of polyurethane material between the outer and inner PTFE layers of the catheter to ensure better bonding of the PTFE of the outer, intermediate and inner layers of the catheter.

The polyurethane is prepared by copolymerizing ammonia and carboxylic acid monomers, wherein the ammonia material block is generally called as a soft block, and the carboxylic acid material block is called as a hard block. The ammonia substance can be polyester or polyether, so that the polyurethane can be divided into two categories of polyester polyurethane and polyether polyurethane according to different soft segment monomer materials. With the same hardness, the polyester polyurethane has better tensile resistance and durability, while the polyether polyurethane has better elasticity, i.e., flexibility. The outer layer of the distal end of a guiding catheter and an interventional catheter which are used clinically is also made of polyurethane material. But are all single polyester polyurethanes or polyether polyurethanes. Such a catheter cannot compromise flexibility, tensile resistance and durability.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the composite material catheter which has high safety performance, strong breaking resistance and pushing performance and excellent comprehensive performance.

In order to solve the technical problem, the invention provides a composite material medical catheter which is characterized in that a catheter body comprises an outermost polymer plastic layer, a second outer polymer plastic layer, a middle metal reinforcing mesh layer and a smooth inner layer; the outermost layer is made of nylon, block polyether amide elastomer, polyurethane or silicon rubber; the secondary outer layer is made of polyurethane, and the middle layer is one or more layers of metal woven meshes or metal spring meshes; the inner layer is made of Polytetrafluoroethylene (PTFE), or high-density polyethylene (HDPE), or block polyether amide elastomer containing friction coefficient reducing additive.

The flexible section of the far end of the catheter adopts at least two layers of polymer plastics, the outermost layer and the secondary outer layer respectively adopt polyester polyurethane materials or polyether polyurethane materials, and the far end of the catheter has more excellent comprehensive performance compared with the conventional guide catheter and interventional catheter, namely, the tensile resistance and the durability of the far end of the catheter are improved under the condition of ensuring sufficient flexibility.

In view of the fact that the intermediate layer of metal reinforcing mesh has a great influence on the catheter stiffness, it is preferable that the metal reinforcing mesh of the compliant section at the distal end of the catheter uses wires with a smaller diameter or a smaller wall thickness, while the metal reinforcing mesh at the proximal end of the catheter uses wires with a larger diameter or a larger wall thickness

Under the condition of the same wall thickness, the spring net has better folding resistance than the woven net, and the woven net has better tensile resistance than the spring net. The preferred catheter is a two-layer metal reinforcing mesh with a woven mesh and a spring mesh.

The invention achieves the following beneficial effects:

1) compared with the conventional guide catheter/interventional catheter, the composite catheter has the advantages that the outer layer of the catheter and the PTFE inner layer of the catheter are combined more firmly, and the safety performance is improved.

2) Compared with the conventional guide catheter/interventional catheter, the composite catheter has the advantages that the distal end of the catheter has better flexibility, tensile resistance and durability when the same mechanical property requirement is met.

3) Compared with the catheter with a pure woven net, the catheter with the layer of the spring net and the layer of the woven net has the advantages that the anti-folding performance of the catheter is improved; and compared with the catheter using a pure spring net, the anti-stretching performance of the catheter is improved.

4) The outer diameter of the far end of the catheter is smaller than that of the main body of the catheter, and the far end of the catheter is more flexible and bending-resistant than the main body of the catheter. Under the same condition, the catheter can be pushed to a far end and a smaller blood vessel, the catheter arrival rate is high, and the success rate of the operation is improved.

Drawings

Fig. 1 is a development view of a composite catheter structure of example 1 of the present invention.

Fig. 2 is a radial cross-sectional view of a composite catheter of example 2 of the present invention.

Figure 3 is an axial cross-sectional view of a composite catheter of example 3 of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the present invention more clearly, and should not be taken as limiting the scope of the present invention.

Example 1

The composite catheter (hereinafter referred to as composite catheter) of the present invention, as shown in fig. 1, comprises an outermost plastic tube 4, a secondary outer layer 3, a tubular woven mesh 2, and an ultrathin Polytetrafluoroethylene (PTFE) tube inner layer 1, and other instruments can reach a distal blood vessel through a catheter lumen 8. Because the wall thickness of the outermost layer of the catheter is gradually reduced, the outer diameter of the catheter of the invention is also gradually reduced from the proximal end to the distal end, and the hardness of the catheter is also gradually reduced from the proximal end to the distal end, so the design is very suitable for tortuous cerebral vessels. The outermost layer materials of the proximal end of the composite catheter and the catheter main body are nylon and Pebax, and the compliant section at the distal end of the catheter is made of polyester polyurethane material; and the secondary outer layer of the distal compliant section of the catheter is made of polyether polyurethane material. The mesh grid of the middle layer is made of one or more of the following materials, including but not limited to: 1) Titanium alloy with tweezers; 2) A cobalt chromium alloy; 3) Stainless steel; 4) Pure platinum and its alloys; 5) Pure tungsten and its alloys. The wire material of the metal wire is a round wire or a flat wire. The diameter of the round wire, the thickness of the flat wire and the width are between 5 and 500 micrometers. Or the spring net can also be formed by winding high polymer wires, and the high polymer wires are made of nylon, PEEK (polyether ether ketone), Liquid Crystal polymer Polymers or silicon rubber.

Under the condition of identical fittings, materials and sizes, a batch of catheter samples with the compliant section at the distal end of the catheter only provided with one polyester polyurethane outer layer are manufactured. The use of the tool model below shows that the distal end of the catheter with the multilayer material of the present invention did not break in the lumen of the model with a bending radius of 5 mm, and the peel force of the inner PTFE layer was 1.5N; and the far end of the catheter with the far-end flexible section provided with only one outer layer of polyester polyurethane material can be broken in a model cavity with the bending radius of 8 mm, and the stripping force of the PTFE inner layer is only 1.0N. The breaking forces at the distal ends of the two batches of catheters are very close.

Example 2

The composite catheter (hereinafter referred to as composite catheter) of the present invention, as shown in fig. 2, includes an outermost plastic tube 4, a secondary outer layer 3, a round tubular spring net (wire) 2, and an ultra-thin Polytetrafluoroethylene (PTFE) tube inner layer 1. In this embodiment, the minor outer layer material wall thickness is about the diameter of the spring wire, so the spring mesh is embedded in the minor outer layer material. The outermost layer materials of the proximal end of the composite catheter and the catheter main body are nylon and Pebax, and the compliant section at the distal end of the catheter is made of polyether polyurethane; and the secondary outer layer of the distal compliant section of the catheter is made of polyester polyurethane material.

Under the condition of identical fittings, materials and sizes, a batch of catheter samples with the compliant section at the distal end of the catheter only provided with one polyether polyurethane outer layer are manufactured. Testing has shown that a catheter of the present invention having multiple layers of material and a single material outer layer can be challenged by a mold cavity of the same bend radius. However, the fracture force of the far end of the catheter with the multi-layer material is 15N, and the fracture force of the far end of the catheter with the far end compliant section only with one polyether polyurethane material outer layer is only 11N.

Example 3

As shown in fig. 3, a catheter tube body 6 of the composite catheter (hereinafter referred to as a composite catheter) of the present invention includes an outermost layer 5 (polyether urethane material), a second outer layer 3 (polyester urethane material), a woven mesh 4, a spring mesh 2, and an ultra-thin Polytetrafluoroethylene (PTFE) inner layer 1. The difference from the above embodiment is that the secondary outer layer 3 is interposed between the woven mesh and the spring mesh.

Under the same conditions of other fittings, materials and dimensions, a batch of catheter samples with only one woven mesh was also prepared. Using the tool model to show that the distal end of the catheter with the woven mesh and the spring mesh of the present invention did not break in the model lumen with a bend radius of 3 mm; and the distal end of the catheter with only one layer of woven mesh would break in a mold cavity with a bend radius of 8 mm. The breaking forces at the distal ends of the two catheters are very close.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. A medical catheter made of composite materials is characterized by comprising a catheter proximal end, a catheter main body and a catheter distal end flexible section, wherein each section of the catheter consists of an outermost layer, a secondary outer layer, an intermediate layer and a smooth inner layer;

the minor outer layer length of the conduit is less than or equal to the outermost layer length of the conduit;

the outermost layer is made of nylon or a block polyether amide elastomer Pebax or polyester polyurethane;

the secondary outer layer material is polyether polyurethane;

the middle layer is one or more sections of metal woven meshes or metal spring meshes;

the inner layer is made of Polytetrafluoroethylene (PTFE), or high-density polyethylene (HDPE), or block polyether amide elastomer (Pebax) containing a friction coefficient reducing additive.

2. The composite medical catheter as claimed in claim 1, wherein the intermediate layer is a metal mesh grid or a spring mesh made of a wire material such as a titanium alloy, a cobalt-chromium alloy or a stainless steel; the wire material is a round wire or a flat wire, and the diameter of the round wire or the thickness of the flat wire is between 5 microns and 500 microns; the diameter of the metal round wire or the thickness of the flat wire at the distal compliant section of the catheter is not more than that of the metal round wire or the flat wire of the catheter main body, and a plurality of sections of metal woven meshes are welded, bonded or lapped together; the intermediate layer comprises at least one layer of the woven mesh and at least one layer of the spring mesh, the woven mesh being shorter than the spring mesh.

3. The composite medical catheter as claimed in claim 1, wherein the outermost layer of the compliant section at the distal end of the catheter has a hardness and/or thickness no greater than the hardness and/or thickness of the outermost layer of the catheter body, and the outermost layer of the catheter body has a hardness and/or thickness no greater than the hardness and/or thickness of the outermost layer of the proximal end of the catheter.

4. The composite medical catheter as claimed in claim 1, wherein one or more of a developer ring or a developer spring is disposed between the outermost layer and the next outer layer of the catheter distal compliant section, and the developer ring or the developer spring is made of pure platinum or an alloy thereof, or pure gold or an alloy thereof, or pure tungsten or an alloy thereof, or pure tantalum or an alloy thereof.

5. The composite medical catheter of claim 1, wherein one or more side holes are formed in the distal end of the catheter, the side holes having a diameter of between 5 microns and 500 microns.

6. A medical catheter made of composite materials is characterized by comprising a catheter proximal end, a catheter main body and a catheter distal end flexible section, wherein each section of the catheter consists of an outermost layer, a secondary outer layer, an intermediate layer and a smooth inner layer;

the outermost layer is made of nylon or a block polyether amide elastomer Pebax or polyether polyurethane;

the secondary outer layer material is polyester polyurethane;

7. The composite medical catheter as claimed in claim 6, wherein the intermediate layer is a metal mesh grid or a spring mesh made of a wire material such as a titanium alloy, a cobalt-chromium alloy or a stainless steel; the wire material is a round wire or a flat wire, and the diameter of the round wire or the thickness of the flat wire is between 5 microns and 500 microns; the diameter of the metal round wire or the thickness of the flat wire at the distal compliant section of the catheter is not more than that of the metal round wire or the flat wire of the catheter main body, and a plurality of sections of metal woven meshes are welded, bonded or lapped together; the intermediate layer comprises at least one layer of the woven mesh and at least one layer of the spring mesh, the woven mesh being shorter than the spring mesh.

8. The composite medical catheter as claimed in claim 6, wherein the outermost layer of the compliant section at the distal end of the catheter has a hardness and/or thickness no greater than the hardness and/or thickness of the outermost layer of the catheter body, and the outermost layer of the catheter body has a hardness and/or thickness no greater than the hardness and/or thickness of the outermost layer of the proximal end of the catheter.

9. The composite medical catheter as claimed in claim 6, wherein one or more of a developing ring or a developing spring is disposed between the outermost layer and the next outer layer of the catheter distal compliant section, and the developing ring or the developing spring is made of pure platinum or an alloy thereof, or pure gold or an alloy thereof, or pure tungsten or an alloy thereof, or pure tantalum or an alloy thereof.

10. The composite medical catheter of claim 6, wherein one or more side holes are formed in the distal end of the catheter, the side holes having a diameter of between 5 microns and 500 microns.