CN-122006064-A - Microcatheter and method for preparing same

CN122006064ACN 122006064 ACN122006064 ACN 122006064ACN-122006064-A

Abstract

The invention provides a microcatheter and a preparation method thereof, wherein the microcatheter comprises an outer layer, an inner layer, a weaving layer and a developing ring, the outer layer is coated outside the weaving layer and the developing ring, the inner layer is lined inside the weaving layer and the developing ring, the developing ring is coaxially welded to the far end of the weaving layer through a plurality of first welding spots distributed in the circumferential direction, and the outer diameter of the developing ring does not exceed the circumferential wrapping contour range of the far end of the weaving layer. So configured, by coaxially welding the developing ring to the distal end of the braid, the outer diameter of the developing ring does not exceed the circumferential envelope of the distal end of the braid, eliminating the abrupt increase in the outer diameter of the distal end portion of the microcatheter, and making the outer diameter of the microcatheter uniform. The butt welding of the developing ring and the weaving layer also reduces the rigidity abrupt change of the developing ring area, reduces the occurrence of stress concentration phenomenon, improves the fatigue life of the interface of the weaving layer and the developing ring, and effectively takes into account the development, the flexibility and the durability of the microcatheter.

Inventors

CHEN ZHAOYANG
NIE JINGMIN
LIU CHEN
YAO YINGZHONG
ZHAO RUIHUI
YUE BIN

Assignees

福建医科大学附属协和医院
微创龙脉医疗科技(嘉兴)有限公司

Dates

Publication Date: 20260512
Application Date: 20260121

Claims (11)

1. A microcatheter is characterized by comprising an outer layer, an inner layer, a woven layer and a developing ring, wherein the outer layer is coated outside the woven layer and the developing ring, the inner layer is lined inside the woven layer and the developing ring, the developing ring is coaxially welded to the far end of the woven layer through a plurality of first welding spots distributed in the circumferential direction, and the outer diameter of the developing ring does not exceed the circumferential wrapping contour range of the far end of the woven layer.
2. The microcatheter of claim 1, wherein the proximal face of the developing ring has a plurality of micro grooves having a depth of 10-30 μm.
3. The microcatheter of claim 2, wherein the proximal face of the developing ring further has a platinum iridium alloy coating covering at least the micro grooves, the platinum iridium alloy coating having a thickness of 0.5-1 μm.
4. The microcatheter of claim 1, wherein the first spot weld has a diameter of 40-60 μm.
5. The microcatheter of claim 1, comprising a proximal section, a transition section and a distal section connected in sequence in an axial direction, wherein the proximal section has an inner diameter of 0.52 + -0.1 mm, the proximal section has a length of 1100 mm-1550 mm, the distal section has an inner diameter of 0.40 + -0.02 mm, the distal section has a length of 50 mm-150 mm, and the transition section has a length of 50 mm-100 mm.
6. The microcatheter of claim 5, wherein the braid is braided from braided filaments, wherein the intersection points of the braided filaments at the proximal segment are connected by a second weld, wherein the intersection points of the braided filaments at the transition segment are connected by a third weld, wherein the second weld has a diameter of 180-220 μm and the third weld has a diameter of 85-115 μm.
7. The microcatheter of claim 5, wherein the inner wall of the transition section is provided with a micro-spiral diversion trench, the depth of the micro-spiral diversion trench is 5-15 μm, and the pitch of the micro-spiral diversion trench is 0.3-0.7 mm.
8. The microcatheter of claim 5, wherein the inner layer at the proximal section is distributed with glass fiber reinforced polyether block amide and the inner layer at the distal section is distributed with nanodiamond particles.
9. The microcatheter of claim 5, wherein the outer layer of the proximal segment is polyamide with a shore hardness of 72 d-90 d, the outer layer of the transition segment is polyether block amide with a shore hardness of 55 d-74 d, and the outer layer of the distal segment is polyether block amide with a shore hardness of 35 d-55 d.
10. The microcatheter of claim 9, wherein the outer layer at the proximal section is embedded in the braid at the proximal section, and wherein the outer layer at the distal section is distributed with barium sulfate developing particles.
11. A method of manufacturing a microcatheter according to any of claims 1-10; the preparation method of the microcatheter comprises the following steps: Attaching the inner layer to the outside of the mandrel, and sleeving the braiding layer outside the inner layer; Cutting the distal ends of the knitting wires of the knitting layers into rings, electrochemically polishing and deburring, and welding a plurality of circles at the crossing points of the knitting wires within the range of 2 mm-10 mm away from the tail ends; The developing ring is in parallel butt joint with the far end of the weaving layer, and laser welding is completed under the protection of liquid nitrogen cooling; And sleeving the outer layer outside the weaving layer and the developing ring, and performing thermoforming on the outer layer.

Description

Microcatheter and method for preparing same Technical Field The invention relates to the technical field of medical instruments, in particular to a microcatheter and a preparation method of the microcatheter. Background In clinical use, the development property (X-ray radiopacity) and flexibility passing property of the far end of the micro-catheter are inherently contradictory, namely, the traditional micro-catheter adopts a sleeved platinum iridium alloy development ring, the development ring and a metal braiding layer are fixed through gluing, the design not only leads to the increase of the outer diameter of the catheter in the area of the development ring, but also leads to the rigidity surge of the far end of the catheter, the concentration of bending stress, the fatigue fracture of the end face where the metal braiding layer and the development ring are connected easily, and the risk of clinical use of the device is increased. Disclosure of Invention The invention aims to provide a microcatheter and a preparation method thereof, which are used for solving the problems of fixed thickening and stress concentration of a developing ring of the conventional microcatheter. In order to solve the technical problems, the invention provides a microcatheter which comprises an outer layer, an inner layer, a woven layer and a developing ring, wherein the outer layer is coated outside the woven layer and the developing ring, the inner layer is lined inside the woven layer and the developing ring, the developing ring is coaxially welded to the far end of the woven layer through a plurality of first welding spots distributed in the circumferential direction, and the outer diameter of the developing ring does not exceed the circumferential wrapping contour range of the far end of the woven layer. Optionally, the proximal surface of the developing ring has a plurality of micro grooves, and the depth of the micro grooves is 10 μm to 30 μm. Optionally, the proximal end face of the developing ring is further provided with a platinum-iridium alloy coating at least covering the micro-groove, and the thickness of the platinum-iridium alloy coating is 0.5-1 μm. Optionally, the diameter of the first welding spot is 40-60 μm. Optionally, the microcatheter comprises a proximal section, a transition section and a distal section which are sequentially connected in the axial direction, wherein the inner diameter of the proximal section is 0.52+/-0.1 mm, the length of the proximal section is 1100-1550 mm, the inner diameter of the distal section is 0.40+/-0.02 mm, the length of the distal section is 50-150 mm, and the length of the transition section is 50-100 mm. The knitting layer is knitted and formed by knitting yarns, the intersecting points of the knitting yarns at the proximal end section are connected through second welding spots, the intersecting points of the knitting yarns at the transition section are connected through third welding spots, the diameter of the second welding spots is 180-220 microns, and the diameter of the third welding spots is 85-115 microns. Optionally, the inner wall of the transition section is provided with a micro-spiral diversion trench, the depth of the micro-spiral diversion trench is 5-15 μm, and the pitch of the micro-spiral diversion trench is 0.3-0.7 mm. Optionally, glass fiber reinforced polyether block amide is distributed on the inner layer positioned at the proximal section, and nano diamond particles are distributed on the inner layer positioned at the distal section. Optionally, the outer layer located at the proximal section is made of polyamide, the Shore hardness of the outer layer is 72-90D, the outer layer located at the transition section is made of polyether block amide, the Shore hardness of the outer layer is 55-74D, and the outer layer located at the distal section is made of polyether block amide, the Shore hardness of the outer layer is 35-55D. Optionally, the outer layer at the proximal section is embedded in the woven layer at the proximal section, and barium sulfate developing particles are distributed on the outer layer at the distal section. In order to solve the technical problems, the invention also provides a preparation method of the microcatheter, which is used for preparing the microcatheter, and comprises the following steps: Attaching the inner layer to the outside of the mandrel, and sleeving the braiding layer outside the inner layer; Cutting the distal ends of the knitting wires of the knitting layers into rings, electrochemically polishing and deburring, and welding a plurality of circles at the crossing points of the knitting wires within the range of 2 mm-10 mm away from the tail ends; The developing ring is in parallel butt joint with the far end of the weaving layer, and laser welding is completed under the protection of liquid nitrogen cooling; And sleeving the outer layer outside the weaving layer and the developing ring, and performing thermoformin