CN111467650A - Micro-catheter - Google Patents

Abstract

The present disclosure provides a microcatheter comprising an elongated tube body and a tip portion engaged with a front end of the tube body; the tube body is provided with a guide wire inner cavity for slidably receiving a guide wire; the tip part is provided with a cavity communicated with the guide wire inner cavity; the tube body has an inner layer forming a guide wire lumen, a spring layer wound around the inner layer in a wound manner and arranged along a longitudinal direction of the inner layer, a braid layer provided outside the spring layer and surrounding the spring layer, and a polymer layer covering outside the braid layer, wherein the braid layer extends into the tip portion, and the inner layer, the spring layer, and the polymer layer are joined to an end face of the tip portion. Under the circumstances, the tip portion that contracts gradually can help the propulsion of little pipe to improve the propelling movement nature of body, the tip portion can have better bending resistance ability with the part of weaving layer coincidence, from this, can provide a propelling movement nature strong, compliance strong, tensile ability and bending resistance ability all good little pipe with weaving layer.

Description

Micro-catheter

Technical Field

The present disclosure relates to a microcatheter.

Background

With the development of social economy, the national life style is deeply changed, particularly, the aging of population and the urbanization progress are accelerated, the prevalence trend of cardiovascular disease risk factors in China is obvious, and the number of people suffering from cardiovascular diseases is continuously increased. At present, 220 tens of thousands of patients suffering from chronic total occlusion of coronary arteries in China are probably present.

Chronic Total Occlusion (CTO) of the coronary artery refers to a lesion in which the coronary artery is 100% occluded and occluded for more than 3 months, requiring a guidewire to be threaded through the CTO lesion. To increase the success rate of guidewire crossing lesions, a microcatheter is often used in conjunction with the guidewire. After the guidewire first reaches the CTO lesion, the microcatheter is advanced from the guiding catheter into the coronary artery and along the guidewire, and after reaching the CTO lesion, the guidewire attempts to traverse the CTO lesion. Compared with the traditional coronary intervention method, the distance between the microcatheter and the CTO lesion is far smaller than that between the guide catheter and the CTO lesion, so that stronger supporting force can be provided for the guide wire, and the guide wire can pass through the CTO lesion. In addition, due to the small size of the microcatheter, the microcatheter can alternately advance during the process of opening a CTO lesion, and can improve continuous additional supporting force for a guide wire to pass through the CTO lesion.

In the prior art, the microcatheter generally comprises a lumen, an inner layer, a braided layer, a spring layer, an outer layer and the like from inside to outside. In some microcatheters, the positions of the braid and spring layers may also be interchanged. However, few micro-catheters can ensure small size and good pushing performance and flexibility, and have good bending resistance. Particularly, the head of the microcatheter is the most likely location where stress concentration and bending occur. Because the tip and the body of the microcatheter have a large difference in flexibility, the bending phenomenon is often likely to occur where the difference in flexibility is large.

Disclosure of Invention

The present disclosure has been made in view of the above-mentioned prior art, and an object of the present disclosure is to provide a microcatheter with high pushability, high flexibility, and excellent tensile strength and bending resistance.

To this end, the present disclosure provides a microcatheter characterized in that it comprises an elongated tubular body and a tip portion joined to the front end of the tubular body; the tube body has a guidewire lumen that slidably receives a guidewire; the tip part is provided with a cavity communicated with the guide wire inner cavity; the catheter body has an inner layer forming the guide wire lumen, a spring layer wound around the inner layer in a wound manner and arranged in a longitudinal direction of the inner layer, a braid layer provided outside the spring layer and surrounding the spring layer, and a polymer layer covering outside the braid layer, wherein the braid layer extends into the tip portion, and the inner layer, the spring layer, and the polymer layer are joined to an end surface of the tip portion.

In the microcatheter according to the present disclosure, the tapered tip portion is engaged with a tube body, and the guide wire is movable through a guide wire lumen of the tube body, and the tube body has an inner layer, a spring layer, a braid layer and a polymer layer, and the braid layer extends into the tip portion. Under this condition, the tip portion that contracts gradually can help the propulsion of little pipe, and the inlayer of body, spring layer, weaving layer and the polymer layer from inside to outside set gradually to improve the propelling movement nature of body, the tip portion can have better bending resistance ability with the part of weaving layer coincidence, from this, can provide a propelling movement nature strong, the compliance is strong, tensile strength and bending resistance ability are good little pipe.

In addition, in the microcatheter according to the present disclosure, optionally, the elastic modulus of the tip portion is smaller than the elastic modulus of the tube body so that the tip portion is softer than the tube body. This reduces the overall elastic modulus of the tip section, and improves the flexibility of the tip section.

In addition, in the microcatheter according to the present disclosure, optionally, the tip portion is coupled to the tube body so that the tip portion covers the extended portion of the braid and is coupled to the tube body by welding. This can improve the elastic modulus of the tip portion.

In addition, in the microcatheter according to the present disclosure, optionally, the tip portion has a transition section coated with the braided layer and a free section not coated with the braided layer, and an elastic modulus of the transition section is between an elastic modulus of the tubular body and an elastic modulus of the free section. In this case, the elastic modulus of the entire microcatheter gradually decreases from the tube body to the tip portion, and the flexibility of the entire microcatheter can be improved.

In addition, in the microcatheter according to the present disclosure, optionally, at the junction of the tube body and the tip portion, the inner diameter of the guide wire lumen has a size equal to the inner diameter of the lumen, and the outer diameter of the tip portion has a size equal to the outer diameter of the tube body. Thereby, the engagement can be facilitated and the sliding of the guide wire can be facilitated.

Additionally, in the microcatheter of the present disclosure, optionally, the microcatheter further comprises a coating applied to the guidewire lumen and the inner wall of the lumen. Thereby, the guide wire can be facilitated to pass through the micro-catheter.

In addition, in the microcatheter according to the present disclosure, optionally, the spring layer is made by spirally winding a wire material on the inner layer in a winding manner, and the braid is made by braiding a wire material on an outer side of the spring layer. In this case, even if torque is continuously input from the outside, the spring layer is protected by the outer braid so as not to be scattered, and thus, the reliability of the microcatheter can be improved.

Additionally, in the microcatheter to which the present disclosure relates, optionally, the thickness of the spring layer is greater than the thickness of the braid layer. Therefore, the micro-catheter can obtain enough supporting force through the spring layer, and the pushing performance of the micro-catheter can be improved.

In addition, in the microcatheter of the present disclosure, optionally, there is a space between adjacent turns in the spring layer in a cross section of the spring layer along the length direction of the tube body. In this case, the spring layer has a sufficient expansion space, and thus, the pushability of the microcatheter can be improved.

In addition, in the microcatheter according to the present disclosure, the tip portion may be tapered from the junction of the tube body. This can further reduce the elastic modulus of the tip portion at the end away from the joint, thereby improving the flexibility.

According to this disclosure, can provide a little pipe that has weaving layer that pushing nature is strong, compliance is strong, tensile ability and anti bending capability are all good.

Drawings

Embodiments of the present disclosure will now be explained in further detail, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 is a schematic view showing the overall structure of a microcatheter with a braided layer according to an embodiment of the present disclosure.

Fig. 2 is a schematic view showing the catheter hierarchy of a microcatheter with a braided layer according to an embodiment of the present disclosure.

Fig. 3 is a partially enlarged schematic view illustrating a micro-catheter with a braided layer according to an embodiment of the present disclosure.

Fig. 4 is a schematic view showing a cross-sectional structure of the pipe body along the BB' direction in fig. 3 according to the embodiment of the present disclosure.

Fig. 5 is a schematic sectional view showing the structure in the AA' direction in fig. 3 according to the embodiment of the present disclosure.

Fig. 6 is a schematic cross-sectional view illustrating another angle of the structure of the micro-catheter with a braided layer according to the embodiment of the present disclosure.

The reference numbers illustrate:

1 … microcatheter, 11 … tubular body, 111 … inner layer, 112 … spring layer, 113 … braid, 114 … polymer layer, 12 … tip, 2 … catheter hub.

Detailed Description

The present disclosure will be described in further detail below with reference to the accompanying drawings and specific embodiments. In the drawings, the same components or components having the same functions are denoted by the same reference numerals, and redundant description thereof will be omitted.

Fig. 1 is a schematic view showing the overall structure of a micro catheter 1 having a braided layer according to an embodiment of the present disclosure.

As shown in fig. 1, in the present embodiment, a microcatheter 1 having a braided layer (also referred to as "microcatheter 1" in some cases) according to the present disclosure includes atube body 11 and atip portion 12. Thetip 12 may be tapered from the juncture of thetube 11. Thetubular body 11 may have aninner layer 111, aspring layer 112, abraid layer 113, and apolymer layer 114 sequentially disposed from the inside to the outside. Thetip portion 12 coincides with thespring layer 112 or thebraid layer 113 in projection in the radial direction. In this case, the gradually-contractedtip portion 12 can contribute to the pushing of the microcatheter 1, theinner layer 111, thespring layer 112, thebraid layer 113 and thepolymer layer 114 of thetube body 11 are sequentially arranged from inside to outside, so that the pushing performance of thetube body 11 is improved, and the projection overlapping part of thetip portion 12 and thespring layer 112 or thebraid layer 113 in the radial direction can have good bending resistance, so that the microcatheter 1 with strong pushing performance, strong flexibility, and good tensile strength and bending resistance can be provided.

In some examples, thetube body 11 may have a guidewire lumen that slidably receives a guidewire. Thetube body 11 may include aninner layer 111 forming a guide wire lumen, aspring layer 112 wound around theinner layer 111 in a winding manner and arranged along a longitudinal direction of theinner layer 111, abraid layer 113 provided outside thespring layer 112 and surrounding thespring layer 112, and apolymer layer 114 covering an outside of thebraid layer 113.

In some examples, thetip 12 may be tapered from the juncture of thetube 11, and in addition, thetip 12 may have a lumen in communication with the guidewire lumen.

In some examples,braid 113 extends intotip portion 12, andinner layer 111,spring layer 112, andpolymer layer 114 engage an end face oftip portion 12.

In the microcatheter 1 having the braided layer according to the present disclosure, the tapereddistal end portion 12 is joined to thetube body 11, the guide wire can move through the guide wire lumen of thetube body 11, thetube body 11 has theinner layer 111, thespring layer 112, thebraided layer 113, and thepolymer layer 114, and thebraided layer 113 extends into thedistal end portion 12. In this case, the gradually-contractedtip portion 12 can contribute to the propulsion of the microcatheter 1, theinner layer 111, thespring layer 112, thebraid layer 113 and thepolymer layer 114 of thetube body 11 are sequentially arranged from inside to outside, so that the pushing performance of thetube body 11 is improved, and the part of thetip portion 12, which is overlapped with thespring layer 112 or thebraid layer 113 in the projection in the radial direction, can have better bending resistance, so that the microcatheter 1 with the braid layer, which has strong pushing performance, strong flexibility, and excellent tensile strength and bending resistance, can be provided.

In some examples, acatheter hub 2 may be attached to one end of the microcatheter 1. In some examples,catheter hub 2 may be passed over a guidewire.

In this embodiment, the interventional treatment of Chronic Total Occlusion (CTO) of coronary artery includes firstly pushing a guide wire to the coronary artery and reaching the position of Chronic Total Occlusion of coronary artery, then making the micro-catheter 1 with a tip part enter the position of Chronic Total Occlusion of coronary artery along the guide wire, then making the guide wire enter the lesion area by using the supporting force of the micro-catheter 1, then making the micro-catheter 1 advance along the guide wire and enter the lesion area, and finally making the guide wire cross the region of Chronic Total Occlusion of coronary artery by using the supporting force provided by the micro-catheter 1 with a tip part to the guide wire.

In some examples, the microcatheter 1 may be advanced with the guidewire during crossing of the lesion area. Thereby, the supporting force can be continuously provided to the guide wire.

In other examples, the microcatheter 1 may be advanced alternately with a guidewire. Specifically, the micro-catheter 1 can perform crossing of the lesion region in turn with the guide wire, thereby improving the reliability of the crossing and providing a continuous supporting force to the guide wire.

Fig. 2 is a schematic view showing a catheter-level structure of the micro-catheter 1 with a braided layer according to the embodiment of the present disclosure. Fig. 3 is a partially enlarged schematic view showing the micro-catheter 1 with a braided layer according to the embodiment of the present disclosure. Fig. 4 is a schematic cross-sectional view showing thepipe body 11 along the direction BB' in fig. 3 according to the embodiment of the present disclosure.

In some examples, as described above, thetube body 11 may have a guidewire lumen (not shown) that slidably receives a guidewire.

As shown in fig. 2, 3, 4, in some examples, thetubular body 11 may have aninner layer 111, aspring layer 112, abraid 113, and apolymer layer 114, as described above. Specifically, theinner layer 111, thespring layer 112, thebraid layer 113, and thepolymer layer 114 are disposed in close contact with each other (see fig. 4 and 6), whereby the fastening property and reliability of the micro-catheter 1 can be improved.

In some examples, thetubular body 11 can have aninner layer 111 that forms a guidewire lumen.

In some examples, theinner layer 111 may be made of one of Polytetrafluoroethylene (PTFE), Fluorinated Ethylene Propylene (FEP), perfluoroalkoxy alkane (PFA), polyethylene terephthalate (PET), or Polyetheretherketone (PEEK).

In some examples, thepipe body 11 may have aspring layer 112 wound around theinner layer 111 in a winding manner and arranged along a length direction of theinner layer 111.

In some examples, thespring layer 112 may be made of metal, and in particular, thespring layer 112 may be made of 304 stainless steel wire.

In some examples, thetubular body 11 may have abraid 113 disposed outside of thespring layer 112.

In some examples,braid 113 may be made of metal or fiber, and in particular, may be made of 304 stainless steel material.

In some examples, thetube 11 may have apolymer layer 114 overlying the outer side of thebraid 113.

In some examples, thepolymer layer 114 may be made of one of a polyamide material, a polyether block polyamide, a polyurethane material, an elastomer, or a synthetic rubber.

In some examples,inner layer 111 andpolymer layer 114 may not have a distinct boundary, e.g.,inner layer 111 andpolymer layer 114 may be combined together in a fused, flow-over, thermoplastic, etc. manner. In other examples,inner layer 111 andpolymer layer 114 may be made of the same material.

In some examples, thespring layer 112 may be made by spirally winding wire material around theinner layer 111 in a winding manner, and thebraid layer 113 may be made by braiding wire material on the outer side of thespring layer 112. In this case, even if torque is continuously input from the outside, thespring layer 112 is protected by theouter braid 113 so as not to be scattered, and thus, the reliability of the micro catheter 1 can be improved.

In some examples, adjacent turns in thespring layer 112 may have a spacing therebetween in a cross section of thespring layer 112 along the length of thepipe body 11. In this case, thespring layer 112 has a sufficient expansion space, and thus, the pushability of the microcatheter 1 can be improved.

In some examples, the wire used for thespring layer 112 may be a flat wire. In some examples, the braided wire used forbraid 113 may be a flat wire. In some examples, a flat wire may refer to a wire that is rectangular in cross-section. Specifically, thespring layer 112 and thebraid layer 113 may be wound around theinner layer 111 with the wide surface of the flat wire facing theinner layer 111, thereby reducing the thickness of thespring layer 112 and thebraid layer 113.

In other examples, the thickness of the flat wire used forspring layer 112 may be the same as the thickness of the flat wire used forbraid layer 113. Additionally, in some examples, the wire thickness of thespring layer 112 may be greater than the wire thickness of thebraid layer 113. Thus, the microcatheter 1 can obtain a sufficient supporting force by thespring layer 112, and the pushability of the microcatheter 1 can be improved.

In other examples, the thickness of the flat wire used forspring layer 112 andbraid layer 113 may be uniform. In other examples, the thickness of the flat wire used for thespring layer 112 and thebraid layer 113 may be non-uniform.

In the present embodiment, theinner layer 111, thespring layer 112, and thepolymer layer 114 may be bonded to the end surface of thetip portion 12. In some examples,inner layer 111 andpolymer layer 114 may be engaged with an end face oftip portion 12. In this case, thespring layer 112 may be isolated by thepolymer layer 114, i.e., thespring layer 112 does not extend to thetip portion 12, thereby improving the flexibility of the entire microcatheter 1.

In some examples, thespring layer 112 may be disposed along a circumferential direction of theinner layer 111 and closely adjacent to theinner layer 111. For example, thespring layer 112 may be formed by winding a wire in a clockwise direction. In addition, thespring layer 112 may be formed by winding a wire in a counterclockwise direction.

In some examples,braid layer 113 may be disposed along a circumferential direction ofinner layer 111 andproximate spring layer 112. For example, thebraid 113 may be formed by winding a braid wire in a clockwise direction. In addition, thebraid 113 may be formed by winding a braid wire in a counterclockwise direction. In other examples, thebraided layer 113 may also be interlaced in a mesh shape by braiding wires.

Fig. 5 is a schematic sectional view showing the structure in the AA' direction in fig. 3 according to the embodiment of the present disclosure. Fig. 6 is a schematic structural cross-sectional view illustrating another angle of thetubular body 11 of the micro catheter 1 with a braided layer according to the embodiment of the present disclosure.

As shown in fig. 5 and 6, in the present embodiment, thepointed end 12 can be joined to the distal end of theelongated tube 11.

In some examples, the inner diameter of the guidewire lumen is equal in size to the inner diameter of the lumen and the outer diameter of thetip 12 is equal in size to the outer diameter of thetube 11 at the juncture of thetube 11 and thetip 12. Thereby, the engagement can be facilitated and the sliding of the guide wire can be facilitated.

Specifically, the outer diameter of the portion of thetip portion 12 that is joined to thetube body 11 coincides with the outer diameter of thetube body 11 at a position near the joint. Therefore, the flexibility of thepipe body 11 can be gradually changed, and the bending resistance and the tensile resistance are improved.

In some examples, thetip 12 tapers from the juncture of thetube 11. This can further reduce the elastic modulus of thetip portion 12 at the end away from the joint, thereby improving the flexibility.

In some examples, the tapering of thetip portion 12 may be a uniform reduction. In other examples, the tapering of thetip portion 12 may be in a manner that the position closer to the tip of thetip portion 12 is more reduced in magnitude. Additionally, in some examples, the tapering of thetip portion 12 may be in a manner that reduces the magnitude closer to the location of thetip portion 12. In other examples, the tapering of thetip portion 12 may be a gradual reduction in a stepped manner. In this case, the manner of reduction may be selected as needed, whereby different flexibility can be obtained according to the manner in which thetip portion 12 is reduced.

In some examples, the modulus of elasticity at the junction of thetube 11 and thetip 12 is between the modulus of elasticity of thetube 11 and thetip 12. In this case, the overall flexibility of the microcatheter 1 can be improved by gradually decreasing the elastic modulus of the microcatheter 1 from thetube 11 to thetip 12.

In the present embodiment, thebraided layer 113 extends into thetip portion 12. Thereby, the elastic modulus of the entire microcatheter 1 gradually decreases from thetube 11 to thedistal end 12.

Specifically, in some examples, one end ofbraid 113 may be closer to tipportion 12, i.e., penetrate intotip portion 12, than an end ofspring layer 112 on the same side as the one end of braid 113 (see fig. 5). This can improve the strength of the joint between thetip portion 12 and thetube 11, and further improve the bending resistance of the microcatheter 1.

In other examples, thetip portion 12 may be engaged with thetubular body 11 such that thetip portion 12 wraps around an extended portion of thebraid 113 and engages thetubular body 11 in a welded manner. (see fig. 6). This can increase the elastic modulus of thetip section 12.

In some examples, the modulus of elasticity of thetip portion 12 is less than the modulus of elasticity of thetube 11 such that thetip portion 12 is softer than thetube 11. This can reduce the overall elastic modulus of thedistal end portion 12, improve the flexibility of thedistal end portion 12, and improve the pushability and reliability of the micro-catheter 1 having the braided layer.

In some examples, the material of thetip portion 12 may be the same as the material of thepolymer layer 114. In other examples, a material having a lower modulus of elasticity than the material of thepolymer layer 114 may be used for the material of thetip portion 12.

In some examples, the hardness oftip portion 12 may be less than the hardness ofpolymer layer 114. In this case, the flexibility of the entire microcatheter 1 can be improved, and the ability of the tip to pass through a lesion can be improved.

In some examples, thetip portion 12 has a transition section coated with thebraid 113 and a free section not coated with thebraid 113, and specifically, there is no clear boundary between the transition section and the free section, and the elastic modulus of the transition section is between the elastic modulus of thetube body 11 and the elastic modulus of the free section. In this case, the overall flexibility of the microcatheter 1 can be improved by gradually decreasing the elastic modulus of the microcatheter 1 from thetube 11 to thetip 12.

In some examples, thetip portion 12 may have a lumen in communication with the guidewire lumen, which may have an inner diameter no greater than the inner diameter of the guidewire lumen. Specifically, in some examples, the inner diameter of the lumen may be equal to the inner diameter of the guidewire lumen. In other examples, the inner diameter of the lumen may be less than the inner diameter of the guidewire lumen but greater than the inner diameter of the guidewire.

In some examples, the microcatheter 1 further includes a coating applied to the inner wall of the guidewire lumen and lumen. Thereby, the passage of the guide wire in the micro-catheter 1 can be facilitated. In particular, the coating may be a high lubricity hydrophilic polymer. In other examples, a coating may also be applied to the outer wall of thepolymer layer 114 of the microcatheter 1. Thereby, the friction force can be reduced to facilitate pushing.

While the present disclosure has been described in detail in connection with the drawings and examples, it should be understood that the above description is not intended to limit the disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from the true spirit and scope of the disclosure, which fall within the scope of the invention.

Claims (10)

1. A microcatheter comprising an elongated tubular body and a tip portion joined to a forward end of said tubular body; the tube body has a guidewire lumen that slidably receives a guidewire; the tip part is provided with a cavity communicated with the guide wire inner cavity; the catheter body has an inner layer forming the guide wire lumen, a spring layer wound around the inner layer in a wound manner and arranged in a longitudinal direction of the inner layer, a braid layer provided outside the spring layer and surrounding the spring layer, and a polymer layer covering outside the braid layer, wherein the braid layer extends into the tip portion, and the inner layer, the spring layer, and the polymer layer are joined to an end surface of the tip portion.

2. The microcatheter of claim 1, wherein:

the tip portion has a modulus of elasticity less than the modulus of elasticity of the tube body so that the tip portion is softer than the tube body.

3. The microcatheter of claim 1, wherein:

the tip portion is engaged with the tube body so that the tip portion covers the extended portion of the braid and is engaged with the tube body by welding.

4. The microcatheter of claim 1 or 3, wherein:

the tip portion has a transition section coated with the braided layer and a free section not coated with the braided layer, and the elastic modulus of the transition section is between the elastic modulus of the tube body and the elastic modulus of the free section.

5. The microcatheter of claim 1, wherein:

at the joint of the tube body and the tip part, the size of the inner diameter of the guide wire inner cavity is equal to that of the inner diameter of the cavity, and the size of the outer diameter of the tip part is equal to that of the outer diameter of the tube body.

6. The microcatheter of claim 1, wherein:

the microcatheter also includes a coating applied to the guidewire lumen and the inner wall of the lumen.

7. The microcatheter of claim 1, wherein:

the spring layer is made by spirally winding a wire material around the inner layer in a winding manner, and the braid layer is made by braiding a braided wire material on an outer side of the spring layer.

8. The microcatheter of claim 1, wherein:

the thickness of the spring layer is greater than that of the woven layer.

9. The microcatheter of claim 1 or 7, wherein:

on the section of the spring layer along the length direction of the pipe body, adjacent circles in the spring layer have intervals.

10. The microcatheter of claim 1, wherein:

the tip portion is gradually contracted from the joint of the tube body.

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