CN111374813B

CN111374813B - Stent delivery device and stent loading method

Info

Publication number: CN111374813B
Application number: CN201811642855.9A
Authority: CN
Inventors: 吴旭闻; 桂宝珠; 梅杰; 陈国明; 李�雨
Original assignee: Shanghai Microport Cardioflow Medtech Co Ltd
Current assignee: Shanghai Microport Cardioflow Medtech Co Ltd
Priority date: 2018-12-29
Filing date: 2018-12-29
Publication date: 2024-12-06
Anticipated expiration: 2038-12-29
Also published as: WO2020135229A1; CN111374813A

Abstract

The invention provides a stent conveying device which comprises a sheath tube and an inner catheter, wherein the sheath tube is sleeved outside the inner catheter, the inner catheter is in a first expansion state, the stent is pressed and held in the sheath tube in the first expansion state, the inner catheter is in a balloon shape, the outer surface of the inner catheter is attached to the inner wall of the stent in the pressing and holding state, and the outer diameter of the inner catheter is smaller than the inner diameter of the sheath tube. The invention expands the stent through the inner catheter, thereby adjusting the shape of the stent pressed in the sheath, reducing the uneven stress of the stent pressed in the sheath, improving the loading uniformity of the stent, reducing the distortion and the invagination of the stent in the release process caused by the phenomenon, thereby influencing the release quality, damaging the peripheral tissues, affecting the valve fatigue, even damaging the conveying system and influencing the risk of the withdrawal function, and improving the success rate of stent release.

Description

Stent delivery device and stent loading method

Technical Field

The invention relates to the technical field of medical equipment, in particular to a stent conveying device and a stent loading method.

Background

With the development of socioeconomic performance and the aging of population, the incidence of valvular heart disease is obviously increased, and research shows that the incidence of valvular heart disease of the aged population over 75 years is as high as 13.3%. At present, the traditional surgical treatment is still the first treatment means for patients with severe valvular disease, but for the aged, combined multi-organ diseases, patients with history of open chest surgery and poor cardiac function, the traditional surgical treatment has high risk and mortality rate, and some patients do not have the opportunity of operation. The replacement of the transcatheter heart valve has the advantages of no need of chest opening, small trauma, quick recovery of the patient and the like, and is widely paid attention to by expert students.

In the prior art, the phenomenon of uneven stress occurs when the stent is loaded into the sheath tube with a smaller inner diameter, particularly, the phenomenon of uneven stress occurs when the stent is loaded into the sheath tube with a smaller inner diameter for a self-expanding stent with strong radial supporting force, so that the circumferential uniformity of the stent in the lumen of the sheath tube is poor, even the phenomenon of inward recession of the stent occurs, and the loading uniformity of the stent is reduced. This problem is difficult to avoid, and is less likely to be found in opaque sheaths, which can cause distortion and invagination during the actual release of the stent, seriously affect the release quality, damage surrounding tissues, easily cause valve fatigue, even damage the delivery device, and affect the withdrawal of the delivery system.

Disclosure of Invention

The invention aims to provide a stent conveying device and a stent loading method, which are used for solving the problem that the loading uniformity of a stent is not high after the stent is loaded into the existing stent conveying device and the problem that the loading uniformity of the stent is not high when the existing stent loading method is used for loading the stent.

In order to solve the technical problems, the invention provides a stent conveying device, which comprises a sheath tube and an inner catheter, wherein the sheath tube is sleeved outside the inner catheter, the inner catheter has a first expansion state, the stent is pressed and held in the sheath tube in the first expansion state, the inner catheter is in a balloon shape, the outer surface of the inner catheter is attached to the inner wall of the stent in the pressing and holding state, and the outer diameter of the inner catheter is smaller than the inner diameter of the sheath tube.

Optionally, the inner catheter comprises an outer expansion tube and an outer connection catheter, the distal end of the outer connection catheter is connected with the outer expansion tube, the stent is sleeved on the outer surface of the outer expansion tube, and in the first expansion state, the outer expansion tube is in a balloon shape.

Optionally, the inner catheter is also provided with a second expansion state, in the second expansion state, the outer expansion tube is in a balloon shape, the stent is positioned outside the sheath tube and is in an expansion state, the outer surface of the outer expansion tube is attached to the inner wall of the stent, and the outer diameter of the outer expansion tube is larger than the outer diameter of the sheath tube.

Optionally, the inner catheter further has an initial state, and an outer diameter of the inner catheter in the initial state is smaller than an outer diameter of the inner catheter in the first expanded state.

Optionally, the inner catheter further comprises an inner-layer expansion tube, an inner-layer connection tube, a connector and a fixing piece, the stent conveying device further comprises a handle, the outer-layer expansion tube is sleeved on the outer surface of the inner-layer expansion tube, the outer-layer connection tube is sleeved on the outer surface of the inner-layer connection tube, the distal end of the inner-layer connection tube is connected with the inner-layer expansion tube, the distal end of the outer-layer expansion tube and the distal end of the inner-layer expansion tube are fixedly connected with the connector, the proximal end of the outer-layer connection tube and the proximal end of the inner-layer connection tube are fixedly connected with the handle, the fixing piece is fixedly arranged on the outer surface of the outer-layer expansion tube and/or the outer-layer connection tube, and the handle is used for driving the sheath tube to move along the axial direction of the inner catheter on the outer surface of the inner catheter.

Optionally, the outer expansion pipe and the outer connecting catheter and the inner expansion pipe and the inner connecting catheter enclose a first outer pipe cavity, the inner catheter further comprises a first outer valve and a medium conveying device, the first outer valve is arranged between the first outer pipe cavity and the medium conveying device, and the medium conveying device is used for injecting medium into the first outer pipe cavity through the first outer valve.

Optionally, the inner catheter includes outer expansion pipe, outer connecting catheter, middle level expansion pipe and middle level connecting catheter, the distal end of outer connecting catheter with outer expansion pipe is connected, the distal end of middle level connecting catheter with middle level expansion pipe is connected, outer expansion pipe and outer connecting catheter cover are established respectively the middle level expansion pipe with on the surface of middle level connecting catheter, the support cover is established on the surface of outer expansion pipe under the first expansion state, the middle level expansion pipe is the sacculus, outer expansion pipe is folding form.

Optionally, the inner catheter further has a second expansion state, in the second expansion state, the outer expansion tube is balloon-shaped, the stent is located outside the sheath tube and is in an expansion state, the outer surface of the outer expansion tube is attached to the inner wall of the stent, and the outer diameter of the outer expansion tube in the second expansion state is larger than the outer diameter of the sheath tube.

Optionally, the inner catheter further has an initial state, in which the outer layer expansion tube and the middle layer expansion tube are folded, and an outer diameter of the middle layer expansion tube in the first expansion state is larger than an outer diameter of the outer layer expansion tube in the initial state.

Optionally, the inner catheter further includes an inner layer expansion tube, an inner layer connection tube, a connector, a fixing piece and a handle, the middle layer expansion tube is sleeved on the outer surface of the inner layer expansion tube, the middle layer connection tube is sleeved on the outer surface of the inner layer connection tube, the distal end of the inner layer connection tube is connected with the inner layer expansion tube, the distal ends of the outer layer expansion tube, the middle layer expansion tube and the inner layer expansion tube are fixedly connected with the connector, the proximal ends of the outer layer connection tube, the middle layer connection tube and the inner layer connection tube are fixedly connected with the handle, the fixing piece is fixedly arranged on the outer surface of the outer layer expansion tube and/or the outer layer connection tube, the fixing piece is used for fixing the bracket, and the handle is used for driving the sheath tube to move on the outer surface of the inner catheter along the axial direction of the inner catheter.

Optionally, the outer expansion pipe and the outer connecting catheter with the middle expansion pipe and the middle connecting catheter enclose a second outer layer lumen, the middle expansion pipe and the middle connecting catheter with the inner expansion pipe and the inner connecting catheter enclose a middle layer lumen, the inner catheter further comprises a second outer layer valve, a middle layer valve and a medium conveying device, the second outer layer valve is arranged between the second outer layer lumen and the medium conveying device, the middle layer valve is arranged between the middle layer lumen and the medium conveying device, and the medium conveying device is used for injecting a medium into the middle layer lumen through the middle layer valve and injecting a medium into the second outer layer lumen through the second outer layer valve.

The invention also provides a stent loading method of the stent conveying device, which comprises the steps of pressing the stent sleeved on the outer surface of the inner catheter into the lumen of the sheath, injecting a medium into the lumen of the inner catheter, expanding the inner catheter to the first expansion state, enabling the inner catheter to be in a balloon shape, and enabling the outer surface of the inner catheter to be attached to the inner wall of the stent in the pressed state.

Optionally, releasing the medium within the lumen of the inner catheter to place the inner catheter in an initial state is also included.

The stent conveying device and the stent loading method provided by the invention have the following beneficial effects:

Because the support sleeved on the outer surface of the inner catheter is pressed and held in the lumen of the sheath, and in the first expansion state, the inner catheter is balloon-shaped, the outer surface of the inner catheter is attached to the inner wall of the support in the pressing and holding state, and the outer diameter of the inner catheter is smaller than the inner diameter of the sheath, the support can be expanded through the inner catheter, the shape of the support pressed and held in the sheath can be adjusted, the phenomenon that the support pressed and held in the sheath is uneven in stress can be reduced, the circumferential uniformity of the support is improved, the inward concave phenomenon of the support is reduced, the loading uniformity of the support can be improved, the distortion and the inward concave phenomenon of the support in the release process due to the phenomenon are reduced, the release quality is influenced, peripheral tissues are damaged, the valve fatigue is influenced, even a conveying system is damaged, the risk of the withdrawal function is influenced, and the success rate of releasing the support can be improved.

Drawings

FIG. 1 is a schematic structural view of a stent;

FIG. 2 is a schematic view showing a structure of a stent delivery device according to a first embodiment of the present invention;

FIG. 3 is a schematic view showing the structure of an expanded inner catheter of a stent delivery device according to a first embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of an inner catheter in a collapsed state in a stent delivery device according to a first embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of the stent delivery device of FIG. 4 taken along line A-A;

FIG. 6 is a schematic cross-sectional view of a first middle expansion tube in an inner catheter of a stent delivery device according to a first embodiment of the present invention in an expanded state;

FIG. 7 is a schematic view showing a structure of a stent mounted in a stent delivery device according to a first embodiment of the present invention;

FIG. 8 is an enlarged schematic view of a portion of the stent delivery device and stent of FIG. 7;

FIG. 9 is a schematic view showing another structure of a stent loaded in a stent delivery device according to a first embodiment of the present invention;

FIG. 10 is an enlarged schematic view of a portion of the stent delivery device and stent of FIG. 9;

FIG. 11 is a schematic view showing a structure of the stent according to the first embodiment of the present invention after the stent is released from the sheath;

FIG. 12 is a schematic view showing a structure of a stent released from a sheath in a heart according to the first embodiment of the present invention;

FIG. 13 is a schematic view showing another structure of the stent according to the first embodiment of the present invention after the stent is released from the sheath;

FIG. 14 is a schematic view showing another configuration of the stent according to the first embodiment of the present invention after the stent is released from the sheath in the heart;

FIG. 15 is a schematic cross-sectional view of a stent delivery device in a contracted state in accordance with a second embodiment of the present invention;

FIG. 16 is a schematic cross-sectional view of the stent delivery device of FIG. 15 taken along line B-B;

fig. 17 is a schematic cross-sectional view of a stent delivery device in accordance with a second embodiment of the present invention in a first expanded state.

Reference numerals illustrate:

100-bracket, 110-fixed ear, 120-inflow channel structure, 130-outflow channel structure;

reference numerals in the first embodiment describe:

200-outer tube assembly, 210-sheath tube, 220-outer tube;

300-inner conduit, 310-connector;

320-supporting catheter, 321-first outer layer expansion pipe, 322-first middle layer expansion pipe, 323-first inner layer expansion pipe;

330-connecting conduit, 331-first outer connecting conduit, 332-first middle connecting conduit, 333-first inner connecting conduit;

340-first outer layer lumen, 350-middle layer lumen, 360-inner layer lumen;

370-fixing member;

400-handle;

510-a first outer valve;

520-middle layer valve;

reference numerals in the second embodiment describe:

600-outer tube assembly, 610-sheath tube, 620-outer tube;

700-inner catheter;

710-support catheter, 711-second outer stent, 712-second inner stent;

720-connecting conduit, 721-second outer connecting conduit, 722-second inner connecting conduit;

730-connector, 740-fixing piece, 750-second outer layer pipe cavity, 760-second inner layer pipe cavity;

800-handle, 810-second outer layer valve, 820-second inner layer valve.

Detailed Description

Fig. 1 is a schematic structural view of a stent 100, as shown in fig. 1, the stent 100 includes two fixing lugs 110, and an inflow channel structure 120 and an outflow channel structure 130 which are in a net pipe shape, wherein the inflow channel structure 120 and the outflow channel structure 130 are connected, and the two fixing lugs 110 are connected with the outflow channel structure 130.

The stent 100 is generally required to be loaded into a stent delivery device and then delivered to a lesion via the stent delivery device, and then the stent 100 is released to a corresponding location by the stent delivery device, thereby implanting the stent 100 to a corresponding location for treatment of the lesion. After the stent 100 is released to the corresponding position, it may be necessary to adjust the position and shape of the stent 100 using a stent delivery device or other medical apparatus in order to fully exert the therapeutic effect of the stent 100.

After the stent 100 is loaded into the stent delivery device, it is typically crimped onto the inner catheter by a sheath in the stent delivery device. Wherein the sheath tube is sleeved on the outer surface of the stent 100, the inflow channel structure 120 and the outflow channel structure 130 in the stent 100 are sleeved on the outer surface of the inner catheter, and the fixing lugs 110 of the stent 100 are fixed in the sheath tube. In this state, the stent 100 is in a compressed state, and because the inner diameter of the sheath tube is smaller, the stent 100 is prone to uneven stress, especially for the self-expanding stent 100 with very strong radial supporting force, the phenomenon that the stent 100 is uneven stress is more common, the circumferential uniformity of the stent 100 in the lumen of the sheath tube is prone to be poor, even the phenomenon that the stent 100 is recessed inwards occurs, and the loading uniformity of the stent 100 is reduced.

In order to improve the loading uniformity of the stent, the present invention provides a stent delivery device for delivering the stent. The stent delivery device includes an inner catheter and a sheath. The sheath tube is sleeved on the outer surface of the inner catheter, and the inner catheter is used for expanding a stent pressed in the lumen of the sheath tube. Because the sheath pipe is sleeved on the outer surface of the inner catheter, and the inner catheter is used for expanding the stent which is held in the lumen of the sheath pipe in a pressing mode, after the sheath pipe is used for holding the stent on the inner catheter in a pressing mode, the stent can be expanded through the inner catheter, so that the phenomenon that the stress of the stent which is held in the lumen of the sheath pipe in a pressing mode is uneven can be reduced, the circumferential uniformity of the stent is improved, the inward concave phenomenon of the stent is reduced, the loading uniformity of the stent can be improved, the problem that the stent is twisted and sunk in the releasing process due to the phenomenon is reduced, the releasing quality is influenced, peripheral tissues are damaged, valve fatigue is influenced, even a conveying system is damaged, the risk of the retracting function is influenced, and the success rate of stent release can be improved.

Correspondingly, the invention also provides a stent loading method, which comprises the step of expanding the stent held in the lumen of the sheath tube through the inner catheter after the sheath tube holds the stent on the inner catheter, so that the stent loading uniformity is improved, and the stent release success rate is further improved.

The stent delivery device and stent loading method according to the present invention will be described in further detail with reference to the accompanying drawings and specific examples. Advantages and features of the invention will become more apparent from the following description and from the claims. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.

Example 1

The present embodiment provides a stent delivery device. Fig. 2 is a schematic structural view of a stent delivery device according to a first embodiment of the present invention, fig. 3 is a schematic structural view of an expanded inner catheter 300 of the stent delivery device according to the first embodiment of the present invention, fig. 4 is a schematic sectional view of the inner catheter in a folded state of the stent delivery device according to the first embodiment of the present invention, fig. 5 is a schematic sectional view of the stent delivery device according to the line A-A of fig. 4, fig. 6 is a schematic sectional view of a first middle expansion tube in the inner catheter in the stent delivery device according to the first embodiment of the present invention in an expanded state, and referring to fig. 2 to 6, the stent delivery device includes an outer tube assembly 200, the inner catheter 300, a handle 400, a medium delivery device, a first outer layer valve 510, a middle layer valve 520 and a first inner layer valve. Wherein, the inner catheter 300 comprises a connector 310, a supporting catheter 320, a connecting catheter 330 and a fixing member 370 which are sequentially connected from the distal end to the proximal end.

Referring to fig. 4 to 6, the outer tube assembly 200 is sleeved on the outer surface of the inner catheter 300. Specifically, the outer tube assembly 200 is sleeved on the outer surface of the support tube 320 and/or the connection tube 330, and the handle 400 is used to drive the outer tube assembly 200 to move on the outer surfaces of the support tube 320 and the connection tube 330 along the axial direction of the support tube 320 and the connection tube 330.

Specifically, the outer tube assembly 200 includes a sheath tube 210 and an outer tube 220, the sheath tube 210 is fixedly connected with the outer tube 220, and the outer tube 220 is connected with a handle 400. The sheath 210 is used to hold and house the stent 100. The outer tube 220 is specifically connectable with a movable part in the handle 400 so as to be movable by driving the movable part in the handle 400, and thereby the outer tube 220 and the sheath 210 are driven by the movable part in the handle 400 to move axially along the support catheter 320 and the connection catheter 330 on the outer surfaces of the support catheter 320 and the connection catheter 330.

In this embodiment, the outer tube assembly 200 may be driven by the handle 400 to move along the axial direction of the support tube 320 and the connection tube 330, but not rotate around the axial direction of the support tube 320 and the connection tube 330, so as to reduce the risk of the stent 100 being deformed by the rotation of the outer tube assembly 200, which may result in a reduced success rate of releasing the stent 100.

Referring to fig. 4 to 6, the inner and outer diameters of the sheath 210 are both larger than those of the outer tube 220 to reduce the influence on the human body during the delivery of the stent 100 to the lesion by the stent delivery device.

The outer tube assembly 200 may be fabricated from one or more of a metallic material, a polymer/metallic composite material.

Referring to fig. 3-6, the support catheter 320 and the connection catheter 330 may be housed within a lumen of the outer tube assembly 200. The distal end of the support catheter 320 is connected to the connector 310, the proximal end of the support catheter 320 is connected to the distal end of the connection catheter 330, the support catheter 320 is used for expanding the stent 100 held in the lumen of the sheath 210, and the proximal end of the connection catheter 330 is fixedly connected to the handle 400.

Referring to fig. 4 to 6, the support catheter 320 includes a first outer stent 321, a first middle stent 322, and a first inner stent 323. The first outer expansion pipe 321 is sleeved on the outer surface of the first middle expansion pipe 322, and the first middle expansion pipe 322 is sleeved on the outer surface of the first inner expansion pipe 323. The distal ends of the first outer expansion pipe 321, the first middle expansion pipe 322 and the first inner expansion pipe 323 are fixedly connected with the connector 310, and the proximal ends of the first outer expansion pipe 321, the first middle expansion pipe 322 and the first inner expansion pipe 323 are fixedly connected with the distal end of the connecting catheter 330.

The first outer expansion pipe 321 and the first middle expansion pipe 322 have a folded state and an expanded state, respectively. The outer surface of the first outer expansion pipe 321 is folded in a folded state and expanded in a balloon shape in an expanded state. The outer surface of the first middle expansion pipe 322 is folded in a folded state and expanded in a balloon shape in an expanded state. The outer diameter and structure of the first inner stent 323 will not change with different working conditions.

Wherein the outer diameter of the first outer layer expansion tube 321 in the expanded state is larger than the outer diameter of the sheath tube 210, and the outer diameter of the first middle layer expansion tube 322 in the expanded state is smaller than the inner diameter of the sheath tube 210.

The outer diameter of the outer surface of the first outer expansion pipe 321 in the expanded state ranges from 16mm to 40mm, and the outer diameter of the outer surface of the first middle expansion pipe 322 in the expanded state ranges from 4mm to 13 mm.

The material of the first inner expansion pipe 323 may be one of a polymer material and a polymer/metal composite material. The materials of the first middle expansion pipe 322 and the first outer expansion pipe 321 can be polymer materials.

The connector 310 and the support catheter 320 are connected in sequence from the distal end to the proximal end.

Specifically, the connector 310 is a conical head, the large end of the conical head is connected with the supporting conduit 320, and the small end of the conical head is a free end. In other embodiments, the connector 310 may have other shapes, such as a tapered cylindrical structure with an outer diameter gradually increasing from the distal end to the proximal end of the connector 310.

The connector 310 is preferably of a streamlined design to reduce the resistance to movement of the connector 310. The connector 310 is preferably made of a polymer material.

Referring to fig. 4 to 6, the connecting duct 330 includes a first outer layer connecting duct 331, a first middle layer connecting duct 332, and a first inner layer connecting duct 333.

The first outer layer connecting conduit 331 is sleeved on the outer surface of the middle connecting conduit 330, and the first middle connecting conduit 332 is sleeved on the outer surface of the first inner layer connecting conduit 333. The distal end of the first outer layer connecting tube 331 is connected to the first outer layer expansion tube 321, the distal end of the first middle layer connecting tube 332 is connected to the first middle layer expansion tube 322, and the distal end of the first inner layer connecting tube 333 is connected to the first inner layer expansion tube 323. The proximal ends of the first outer connecting tube 331, the first middle connecting tube 332 and the first inner connecting tube 333 are fixedly connected to the handle 400. The first outer layer connecting tube 331 and the first outer layer expansion tube 321, the first middle layer connecting tube 332 and the first middle layer expansion tube 322 enclose a first outer layer lumen 340, the first middle layer connecting tube 332 and the first middle layer expansion tube 322, the first inner layer connecting tube 333 and the first inner layer expansion tube 323 enclose a middle layer lumen 350, and the inner cavities of the first inner layer connecting tube 333 and the first inner layer expansion tube 323 are inner layer lumens 360.

In this embodiment, the outer diameters and structures of the first outer connecting conduit 331, the first middle connecting conduit 332 and the first inner connecting conduit 333 are not changed with different working conditions.

The materials of the first outer connecting conduit 331, the first middle connecting conduit 332 and the first inner connecting conduit 333 may be one of a polymer material and a polymer/metal composite material.

In particular, the first outer layer connecting duct 331, the first middle layer connecting duct 332 and the first inner layer connecting duct 333 are connected with the fixing members in the handle 400 to limit six degrees of freedom of the support duct 320 and the connecting duct 330 so that the support duct 320 and the connecting duct 330 are fixed with respect to the handle 400, thereby reducing the risk of displacement of the stent 100 loaded on the delivery device.

The first inner layer expansion pipe 323 and the first inner layer connection pipe 333 may be woven by using one pipe with uniformly distributed materials, or may be formed by separately manufacturing two pipes and then fixedly connecting the two pipes, wherein the diameters of the two pipes may be the same. The first middle expansion pipe 322 and the first middle connecting pipe 332 are made of different materials and then fixedly connected. The first outer stent 321 and the first outer connecting catheter 331 are made of different materials and then fixedly connected. The purpose of using different materials is to allow the first outer layer expansion pipe 321, the first middle layer expansion pipe 322 to be folded in a folded state and to be expanded in a balloon shape in an expanded state, and the outer diameters and structures of the outer surfaces of the first outer layer connection pipe 331, the first middle layer connection pipe 332, the first inner layer connection pipe 333 and the first inner layer expansion pipe 323 are fixed without change.

The medium delivery device is used for injecting liquid into the first outer layer lumen 340, the middle layer lumen 350 and the inner layer lumen 360, respectively, and extracting liquid from the first outer layer lumen 340, the middle layer lumen 350 and the inner layer lumen 360, respectively. A guidewire may be disposed within the inner lumen 360.

The first outer valve 510, the middle valve 520 and the first inner valve are disposed between the first outer lumen 340 and the media delivery device, between the middle lumen 350 and the media delivery device and between the inner lumen 360 and the media delivery device, respectively.

The fixing member 370 is fixedly provided on an outer surface of the first outer connecting duct 331 among the connecting ducts 330. The fixing member 370 is used for fixing the fixing lug 110 in the bracket 100. The fixing lugs 110 in the stent 100 are generally fixed to the fixing members 370, and then the sheath 210 is gradually moved distally, so that the stent 100 is gradually pressed against the outer surface of the first outer stent 321 in the supporting catheter 320 by the sheath 210. In other embodiments, the securing members 370 may also be fixedly disposed on the outer surface of the first outer stent 321 within the support catheter 320. The fixing member 370 includes a plurality of grooves in which the fixing lugs 110 of the bracket 100 can be fixed. The fixing member 370 is made of one of a metal material and a polymer material.

The handle 400 may employ any one of a manual handle 400, an electric handle 400, or an electric-manual hybrid drive handle 400.

The following describes the loading of the stent 100 into the stent delivery device and the implantation of the stent 100 into a lesion by the stent delivery device.

Fig. 7 is a schematic structural view of a stent 100 mounted in a stent delivery device according to a first embodiment of the present invention, fig. 8 is a schematic structural view of a stent delivery device and a portion of a stent 100 mounted in the stent delivery device according to fig. 7, fig. 9 is a schematic structural view of a stent 100 mounted in a stent delivery device according to a first embodiment of the present invention, fig. 10 is a schematic structural view of a portion of a stent delivery device and a stent 100 mounted in the stent delivery device according to a second embodiment of the present invention, and a process of loading a stent 100 onto a stent delivery device according to fig. 9 is specifically as follows:

first, the outer tube assembly 200 is moved proximally as a whole to the recess exposing the securing member 370 by actuating the handle 400.

Secondly, the two fixing lugs 110 of the stent 100 are clamped in the grooves of the fixing members 370, the stent 100 is stabilized by means of the auxiliary loading tool, the sheath 210 is driven to move distally, the outflow channel of the stent 100 is firstly pressed and held by the sheath 210, the inflow channel of the stent 100 is pressed and held by the sheath 210 as the sheath 210 moves continuously until the sheath 210 completely wraps the stent 100, and the distal end of the stent 100 is simultaneously pressed against the end face of the connector 310 (the end face of the large end of the conical head), so far, the stent 100 is pressed and held by the sheath 210 on the outer surface of the first outer-layer expansion tube 321 in the support catheter 320, and in this case, the first middle-layer expansion tube 322 and the first outer-layer expansion tube 321 are both in a folded state. Reference is made to fig. 7 and 8 for a schematic illustration of stent 100 being crimped onto the outer surface of first outer stent 321 in support catheter 320 by sheath 210.

Then, a medium is injected into the inner catheter 300 to expand the inner catheter 300 to an expanded state to adjust the shape of the stent 100 pressed in the lumen of the sheath 210. Specifically, the medium (liquid or gas) is injected into the middle-layer lumen 350 through the middle-layer valve 520 by the medium delivery device, and the pressure of the medium is maintained in the first pressure state, so that the first middle-layer expansion tube 322 is expanded to an expanded state under the action of the medium, and the first outer-layer expansion tube 321 is expanded through the first middle-layer expansion tube 322, so that the wall of the first outer-layer expansion tube 321 is attached to the inner wall of the stent 100 held in the lumen of the sheath 210, and the stent 100 is uniformly distributed in the lumen of the sheath 210. Reference is now made to fig. 9 and 10 for schematic illustrations of the expanded first outer stent 321 and first middle stent 322. In the process of expanding the first middle expansion tube 322, since the outer diameter of the first outer expansion tube 321 in the expanded state is larger than the outer diameter of the sheath tube 210 and the outer diameter of the first middle expansion tube 322 in the expanded state is smaller than the inner diameter of the sheath tube 210, in addition, the stent 100 is pressed and held in the lumen of the sheath tube 210, only the first middle expansion tube 322 can be expanded to the expanded state, and the first outer expansion tube 321 can be in the folded state.

Thereafter, the liquid in the middle lumen 350 may be withdrawn, thereby restoring the walls of the middle lumen 350 and the first outer lumen 340 to the original state even though the first middle expanded tube 322 is restored to the collapsed state.

The following describes the procedure for implanting the stent 100 into a lesion by a stent delivery device. Fig. 11 is a schematic structural view of the stent 100 according to the first embodiment of the present invention after being released from the sheath 210, fig. 12 is a schematic structural view of the stent 100 according to the first embodiment of the present invention after being released from the sheath 210 in the heart, fig. 13 is a schematic structural view of the stent 100 according to the first embodiment of the present invention after being released from the sheath 210, and fig. 14 is a schematic structural view of the stent 100 according to the first embodiment of the present invention after being released from the sheath 210 in the heart. Referring to fig. 11 to 14, the process of implanting the stent 100 at the lesion by the stent delivery device includes:

First, the distal end of the stent delivery device (the distal end of the connector 310 and the sheath 210, etc.) enters the human body from the puncture, and is delivered to the diseased annulus along the vascular access of the femoral vein or artery (the aortic valve replacement femoral artery access, the mitral valve, the tricuspid valve replacement femoral vein access), in which case the stent 100 is crimped in the sheath 210, and the first middle-layer stent-tube 322 and the first outer-layer stent-tube 321 are both in a folded state.

Next, after the distal end of the stent delivery device reaches the annulus of the designated lesion and the position and angle of the distal end of the stent delivery device are adjusted, the outer tube assembly 200 is moved proximally as a whole by actuating the handle 400, beginning to release the stent 100 until the stent 100 is completely released to the designated position and out of the stent delivery device. Specifically, the inflow channel of the stent 100 is released first during the proximal movement of the sheath 210, and the outflow channel of the stent 100 is slowly released as the sheath 210 is continuously moved until the distal end of the sheath 210 moves to the recess of the fixing member 370 exposing the fixing member 370, so that the stent 100 is completely released from the sheath 210. In this case, the stent 100 is released from the sheath 210, and both the first middle expansion tube 322 and the first outer expansion tube 321 are in a folded state. A schematic view of the stent 100 after release from the sheath 210 can be seen in fig. 11 and 12.

Then, a medium is injected into the inner catheter 300 to expand the first outer stent 321 to an expanded state to adjust the morphology of the released stent 100 (which is in an expanded state). Specifically, a medium (liquid or gas, the liquid may be a liquid with a developing function) is injected into the first outer layer lumen 340 through the first outer layer valve 510 by the medium delivery device, and the pressure of the medium is maintained in a second pressure state, so that the first outer layer expansion tube 321 is expanded to an expanded state under the action of the medium, so that the wall of the first outer layer expansion tube 321 is attached to the inner wall of the released stent 100, a radial supporting force is provided for the stent 100 through the wall of the first outer layer expansion tube 321, and the stent 100 is assisted in a recovery form (when the stent 100 is a memory alloy stent 100, the stent 100 can be recovered in a memory form), thereby enabling the circumferential direction of the released stent 100 to be more uniformly distributed, and better playing the function of the stent 100. In this case, the stent 100 is released from the sheath 210, and the first outer expansion tube 321 is in an expanded state. The schematic of the expanded first outer stent 321 can be seen in FIGS. 13 and 14.

Thereafter, the liquid in the first outer lumen 340 may be withdrawn, thereby restoring the wall of the first outer lumen 340 to the original state, in which case the first outer expanded tube 321 and the first middle expanded tube 322 are restored to the folded state.

Finally, the stent delivery device is withdrawn. Specifically, sheath 210 is driven distally so that connector 310 and sheath 210 are smoothly connected together. Then, the outer tube assembly 200, the support catheter 320, the connection catheter 330, and the like are withdrawn from the human body by the handle 400.

In the stent delivery device of the present embodiment, during loading and releasing the stent 100, the medium may be injected into the first outer lumen 340 through the first outer valve 510 by the medium delivery device, or the medium may be injected into the middle lumen 350 through the middle valve 520 by the medium delivery device, so that the first outer lumen 340 and the middle lumen 350 are inflated.

The present embodiment also provides a stent loading method of loading the stent 100 in the stent delivery device in the first embodiment. The stent loading method comprises the following steps:

first, the stent 100 is crimped onto the outer surface of the inner catheter 300 through the sheath 210.

Next, a medium is injected into the inner catheter 300 to expand the inner catheter 300 to an expanded state to adjust the shape of the stent 100 pressed in the lumen of the sheath 210.

The medium is injected into the inner catheter 300 to expand the inner catheter 300 to an expanded state, so as to adjust the shape of the stent 100 pressed in the lumen of the sheath 210, specifically, the medium is injected into the middle lumen 350 through the middle valve 520 by the medium delivery device to expand the first middle expansion tube 322 to an expanded state under the action of the medium, so that the first outer expansion tube 321 is expanded through the first middle expansion tube 322 to make the wall of the first outer expansion tube 321 fit with the inner wall of the stent 100 pressed in the lumen of the sheath 210, and the shape of the stent 100 pressed in the lumen of the sheath 210 is adjusted under the action of the injected medium.

In the stent delivery device of the present embodiment, since the sheath tube 210 is sleeved on the outer surface of the support catheter 320, and the support catheter 320 is used for expanding the stent 100 held in the lumen of the sheath tube 210, the outer diameter of the outer surface of the first middle expansion tube 322 in the expanded state is smaller than the inner diameter of the sheath tube 210. Therefore, after the sheath tube 210 presses the stent 100 against the support catheter 320, the stent 100 can be expanded by the support catheter 320, that is, by expanding the first middle expansion tube 322 to an expanded state to expand the first outer expansion tube 321 and make the wall of the first outer expansion tube 321 fit against the inner wall of the stent 100 pressed against the lumen of the sheath tube 210, the shape of the stent 100 pressed against the lumen of the sheath tube 210 can be adjusted by the extrusion of the liquid in the middle tube lumen 350, so that the uneven stress of the stent 100 pressed against the lumen of the sheath tube 210 can be reduced, the circumferential uniformity of the stent 100 can be improved, the inward dishing of the stent 100 can be reduced, the loading uniformity of the stent 100 can be improved, and further, the risk that the stent 100 is distorted and sunk in the release process due to the occurrence of the above phenomenon can be reduced, thereby affecting the release quality, damaging the peripheral tissues, affecting the valve fatigue, and even damaging the delivery system, and affecting the release success rate of the stent 100 can be improved.

In the stent delivery device of the present embodiment, since the sheath tube 210 is sleeved on the outer surface of the support catheter 320, the support catheter 320 is used for expanding the stent 100 held in the lumen of the sheath tube 210, and the outer surface of the first outer expansion tube 321 in the expanded state has an outer diameter larger than that of the sheath tube 210. Therefore, after the stent 100 is released from the sheath 210, the first outer expansion tube 321 is expanded to an expanded state, and the wall of the first outer expansion tube 321 is attached to the inner wall of the stent 100 released from the sheath 210, and the shape of the released stent 100 can be adjusted by squeezing the liquid in the first outer lumen 340, so that the stent 100 can be more uniformly distributed in the circumferential direction after being released, the release quality of the stent 100 can be improved, and the function of the stent 100 can be better exerted. Compared with the stent delivery device in the prior art, the stent delivery device in this embodiment can determine whether to adjust the shape of the stent 100 according to the immediate operation result after the stent 100 is released from the sheath 210, that is, whether to expand the first outer layer expansion tube 321 to an expanded state to adjust the shape of the stent 100, if the shape of the stent 100 is required to be adjusted if serious calcification is difficult to self-expand by the stent 100 or the stent 100 is not expanded to an ideal degree under the condition of complex anatomy, the shape of the stent 100 can be adjusted directly by expanding the first outer layer expansion tube 321 to the expanded state to adjust the shape of the stent 100 without withdrawing the stent delivery device from the human body, and then the balloon kit is delivered to the human body to adjust the shape of the stent 100, thereby saving the operation time and simplifying the operation steps, and reducing the risk that the operation time is too long and the operation steps are tedious to cause the vital signs of the patient to be unstable.

It should be noted that, when the first outer layer expansion tube 321 and the first middle layer expansion tube 322 are in the folded state in the first embodiment, it is understood that the first outer layer expansion tube 321 and the first middle layer expansion tube 322 are in the initial state, that is, in the initial state, the outer surfaces of the first outer layer expansion tube 321 and the first middle layer expansion tube 322 are folded, and neither the first outer layer lumen 340 nor the middle layer lumen 350 is filled with a medium, or a part of the medium is filled, but the medium is insufficient to make the outer surface of the first outer layer expansion tube 321 fit with the inner wall of the stent 100, and the outer diameter of the outer surface of the first outer layer expansion tube 321 in the expanded state is larger than the outer diameter in the initial state, and the outer diameter of the outer surface of the first middle layer expansion tube 322 in the expanded state is larger than the outer diameter in the initial state.

Example two

The present embodiment provides a stent delivery device different from that in the first embodiment. Referring to fig. 15 to 17, fig. 15 is a schematic cross-sectional view of a stent delivery device in a contracted state in a second embodiment of the present invention, fig. 16 is a schematic cross-sectional view of a stent delivery device in fig. 15 along line B-B, and fig. 17 is a schematic cross-sectional view of a stent delivery device in a first expanded state in a second embodiment of the present invention, the stent delivery device in this embodiment differs from the stent delivery device in the first embodiment mainly in that the support catheter 710 and the connecting catheter 720 in the stent delivery device in this embodiment are different from the support catheter 320 and the connecting catheter 330 in the stent delivery device in the first embodiment.

Referring to fig. 15 to 17, the stent delivery device includes a handle 800, an outer tube assembly 600, an inner catheter 700, a media delivery device, a second outer valve 810, and a second inner valve 820. Wherein, the inner catheter 700 comprises a connector 730, a supporting catheter 710, a connecting catheter 720 and a fixing member 740 which are sequentially connected from the distal end to the proximal end.

The outer tube assembly 600 includes a sheath 610 and an outer tube 620, the sheath 610 is fixedly connected to the outer tube 620, and the outer tube 620 is connected to the handle 800. The sheath 610 is used to hold and house the stent 100. The outer tube 620 is specifically connectable with a movable member in the handle 800 so as to be movable by driving the movable member in the handle 800, and thereby the outer tube assembly 600 is driven by the movable member in the handle 800 to move axially along the support conduit 710 and the connecting conduit 720 on the outer surfaces of the support conduit 710 and the connecting conduit 720.

The support catheter 710 and the connecting catheter 720 may be housed within the lumen of the outer tube assembly 600. The distal end of the support catheter 710 is connected to the connector 730, the proximal end of the support catheter 710 is connected to the distal end of the connection catheter 720, the support catheter 710 is used for expanding a stent held in the lumen of the sheath 610, and the proximal end of the connection catheter 720 is fixedly connected to the handle 800.

The support catheter 710 includes a second outer stent 711 and a second inner stent 712. The second outer stent 711 is sleeved on the outer surface of the second inner stent 712. The distal ends of the second outer expansion pipe 711 and the second inner expansion pipe 712 are fixedly connected with the connector 730, and the proximal ends of the second outer expansion pipe 711 and the second inner expansion pipe 712 are fixedly connected with the distal end of the connecting catheter 720.

The second outer expanded tube 711 has a contracted state, a first expanded state, and a second expanded state. The outer surface of the second outer stent 711 is not fully expanded or folded together in the contracted state and is balloon-like in both the first and second expanded states. The outer diameter and structure of the second inner stent 712 will not change with different operating conditions. Wherein the outer diameter of the outer surface of the second outer layer expansion tube 711 in the second expanded state is larger than the outer diameter of the sheath 610, and the outer diameter of the outer surface of the second outer layer expansion tube 711 in the first expanded state is smaller than the inner diameter of the sheath 610. The outer diameter of the outer surface of the second outer expansion pipe 711 in the first expansion state ranges from 4mm to 13mm, and the outer diameter of the outer surface of the second outer expansion pipe 711 in the second expansion state ranges from 16mm to 40 mm.

The connecting conduit 720 includes a second outer connecting conduit 721 and a second inner connecting conduit 722.

The second outer connecting duct 721 is sleeved on the outer surface of the second inner connecting duct 722. The second outer connecting tube 721 is connected to the first outer stent tube, and the second inner connecting tube 722 is connected to the first inner stent tube. The second outer connecting tube 721 and the second inner connecting tube 722 are fixedly connected to the handle 800. The second outer connecting tube 721, the second outer expanding tube 711, the second inner connecting tube 722 and the second inner expanding tube 712 enclose a second outer tube cavity 750, and the inner cavities of the second inner connecting tube 722 and the second inner expanding tube 712 are second inner tube cavities 760.

In this embodiment, the outer diameters and structures of the second outer connecting tube 721 and the second inner connecting tube 722 and the second inner expanding tube 712 do not change with different working conditions.

The material of the second outer connecting conduit 721 and the second inner connecting conduit 722 may be one of a polymer material and a polymer/metal composite material.

In particular, the second outer connecting tube 721 and the second inner connecting tube 722 are connected to the fixing members in the handle 800 to limit six degrees of freedom of the support tube 710 and the connecting tube 720. Even though the support conduit 710 and the connecting conduit 720 are fixed relative to the handle 800, thereby reducing the risk of displacement of the stent loaded onto the delivery device.

The second inner layer expansion pipe 712 and the second inner layer connecting pipe 722 can be woven by adopting a pipe with evenly distributed materials, or can be formed by adopting two pipes to be manufactured separately and then fixedly connected, wherein the diameters of the two pipes can be the same. The second outer stent 711 and the second outer connecting catheter 721 are made of different materials and then fixedly connected. The purpose of using different materials is to allow the second outer stent 711 to be folded or in an incompletely expanded state in a contracted state and to be inflated in a balloon shape in a first expanded state and a second expanded state.

The medium transporting means is used to inject liquid into the second outer tube chamber 750 and the second inner tube chamber 760, respectively, and to withdraw liquid from the second outer tube chamber 750 and the second inner tube chamber 760, respectively. A guidewire may be disposed within the second inner lumen 760.

The second outer valve 810 and the second inner valve 820 are disposed between the second outer lumen 750 and the media delivery device and the second inner lumen 760 and the media delivery device, respectively.

In this embodiment, the second outer expansion pipe 711 is an elastomer, and the second outer expansion pipe 711 is made of a high elastic material, for example, a thermoplastic elastomer (TPE), so that the second outer expansion pipe 711 can achieve a first expanded state and a second expanded state. The procedure of injecting a medium into the inner catheter 700 to expand the inner catheter 700 to a first expanded state to adjust the shape of the stent held in the lumen of the sheath 610 during the loading of the stent into the stent delivery device in this embodiment is different from that of the first embodiment. Specifically, the injecting a medium into the inner catheter 700 to expand the inner catheter 700 to the expanded state to adjust the shape of the stent pressed in the lumen of the sheath 610 in this embodiment specifically includes:

The medium (liquid or gas) is injected into the second outer lumen 750 through the first outer valve by the medium delivery device, and the pressure of the medium is maintained in the first pressure state, so that the second outer lumen 750 is expanded to the first expanded state by the medium, and the wall of the second outer expansion tube 711 is attached to the inner wall of the stent held in the lumen of the sheath 610, so that the shape of the stent held in the lumen of the sheath 610 is adjusted. During inflation of the second outer stent 711, the second outer stent 711 may be inflated to the first expanded state, but not to the second expanded state, because the outer diameter of the outer surface of the second outer stent 711 in the first expanded state is smaller than the inner diameter of the sheath 610.

In this embodiment, in the process of implanting a stent into a lesion through a stent delivery device, a medium is injected into the inner catheter 700 to expand the second outer stent 711 to a second expanded state to adjust the shape of the released stent, which is different from the first embodiment. In this embodiment, the step of injecting a medium into the inner catheter 700 to expand the second outer stent 711 to the second expanded state to adjust the shape of the released stent specifically includes:

A medium (liquid or gas, which may be a liquid having a developing function) is injected into the second outer lumen 750 through the second outer valve 810 by the medium delivery device, and the pressure of the medium is maintained in a second pressure state, so that the second outer expansion pipe 711 expands to a second expansion state under the action of the medium, so that the pipe wall of the second outer expansion pipe 711 is attached to the inner wall of the released stent, so as to adjust the shape of the released stent. Wherein, radial supporting force is provided for the stent through the wall of the second outer expansion pipe 711, and the stent is assisted in the recovery form (when the stent is a memory alloy stent, the stent can recover the memory form), so that the circumferential direction of the released stent can be more uniformly distributed, and the function of the stent can be better exerted.

The present embodiment also provides a stent loading method for loading a stent in the stent delivery device in the second embodiment. The stent loading method comprises the following steps:

First, the stent pressed against the outer surface of the inner catheter 700 by the sheath 610 is released from the sheath 610.

Next, a medium is injected into the inner catheter 700 to expand the inner catheter 700 to a second expanded state to adjust the morphology of the released stent.

The medium is injected into the inner catheter 700 to expand the inner catheter 700 to the second expanded state, and the shape of the released stent is specifically that the medium is injected into the second outer lumen 750 through the second outer valve 810 by the medium delivery device, so that the second outer expansion pipe 711 is expanded to the second expanded state under the action of the medium, the wall of the second outer expansion pipe 711 is attached to the shape of the released stent, and the shape of the inner cavity of the released stent is adjusted under the action of the injected medium.

In the stent delivery device of the present embodiment, since the sheath 610 is sleeved on the outer surface of the support catheter 710, and the support catheter 710 is used to expand the stent held in the lumen of the sheath 610, the outer diameter of the outer surface of the second outer expansion tube 711 in the first expanded state is smaller than the inner diameter of the sheath 610. Therefore, after the sheath 610 presses the stent against the support catheter 710, the second outer expansion tube 711 is expanded, and the wall of the second outer expansion tube 711 is attached to the inner wall of the stent pressed against the lumen of the sheath 610, so that the inner catheter 700 is in the first expanded state, and the shape of the stent pressed against the lumen of the sheath 610 can be adjusted under the extrusion of the liquid in the second outer lumen 750, so that the uneven stress of the stent pressed against the lumen of the sheath 610 can be reduced, the circumferential uniformity of the stent can be improved, the inward-concave phenomenon of the stent can be reduced, the loading uniformity of the stent can be improved, and the risk that the stent is distorted and sunk in the release process due to the phenomenon, thereby affecting the release quality, damaging the peripheral tissues, affecting the valve fatigue, even damaging the delivery system, affecting the withdrawal function can be reduced, and the success rate of stent release can be improved.

In the stent delivery device of the present embodiment, since the sheath 610 is sleeved on the outer surface of the support catheter 710, the support catheter 710 is used for expanding the stent held in the lumen of the sheath 610, and the outer surface of the second outer expansion tube 711 in the second expanded state has an outer diameter larger than that of the sheath 610. Therefore, after the stent is released from the sheath 610, the second outer expansion pipe 711 is expanded to the second expansion state, and the pipe wall of the second outer expansion pipe 711 is attached to the inner wall of the stent released from the sheath 610, so that the shape of the released stent can be adjusted under the extrusion of the liquid in the second outer pipe cavity 750, and the released stent can be more uniformly distributed in the circumferential direction, thereby improving the release quality of the stent and better playing the function of the stent. Compared with the stent delivery device in the prior art, the stent delivery device in this embodiment can determine whether to adjust the shape of the stent according to the immediate operation result after the stent is released from the sheath 610, that is, whether to expand the first outer layer expansion tube to an expanded state so as to adjust the shape of the stent, if the stent is difficult to self-expand by the stent due to serious calcification or the stent is not expanded to an ideal degree under the condition of complex anatomical structure, the shape of the stent needs to be adjusted, the stent delivery device can be directly expanded to an expanded state by expanding the first outer layer expansion tube so as to adjust the shape of the stent, the stent delivery device does not need to be withdrawn from a human body, and then the balloon suite is delivered to the human body so as to adjust the shape of the stent, thereby saving the operation time and simplifying the operation steps, and reducing the risks that the operation time is overlong and the operation steps are complicated so that the vital signs of the patient are unstable so as to cause accidents.

It should be noted that, when the second outer expansion pipe 711 is in the contracted state in the second embodiment, it may be understood that the second outer expansion pipe 711 is in an initial state, that is, in this initial state, the outer surface of the second outer expansion pipe 711 is folded or in an unexpanded state, and the second outer pipe cavity 750 is not filled with a medium, or is partially filled with a medium, but the filled medium is insufficient to make the outer surface of the second outer expansion pipe 711 fit with the inner wall of the stent, and the outer diameter of the outer surface of the second outer expansion pipe 711 in the first expanded state is larger than the outer diameter in the initial state.

The "proximal" and "distal" in the above embodiments are relative orientations, relative positions, directions of elements or actions relative to each other from the perspective of the physician using the medical device, although "proximal" and "distal" are not intended to be limiting, and "proximal" generally refers to the end of the medical device that is proximal to the physician during normal operation, and "distal" generally refers to the end that first enters the patient. Furthermore, the term "or" in the above embodiments is used generally in the sense of "and/or" unless explicitly indicated otherwise. In the above embodiments, "both ends" refer to the proximal and distal ends.

The above description is only illustrative of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention, and any alterations and modifications made by those skilled in the art based on the above disclosure shall fall within the scope of the appended claims.

Claims

1. The stent conveying device comprises a sheath tube and an inner catheter, and is characterized in that the sheath tube is sleeved outside the inner catheter, the inner catheter has a first expansion state, the stent is pressed and held in the sheath tube in the first expansion state, the inner catheter is in a balloon shape, the outer surface of the inner catheter is attached to the inner wall of the stent in the pressed and held state, and the outer diameter of the inner catheter is smaller than the inner diameter of the sheath tube;

The inner catheter comprises an outer layer expansion tube, an outer layer connection catheter, a middle layer expansion tube and a middle layer connection catheter, wherein the far end of the outer layer connection catheter is connected with the outer layer expansion tube, the far end of the middle layer connection catheter is connected with the middle layer expansion tube, the outer layer expansion tube and the outer layer connection catheter are respectively sleeved on the outer surfaces of the middle layer expansion tube and the middle layer connection catheter, the stent is sleeved on the outer surface of the outer layer expansion tube, in the first expansion state, the middle layer expansion tube is in a balloon shape, and the outer layer expansion tube is in a folded shape;

The inner catheter is also provided with a second expansion state, in the second expansion state, the outer expansion pipe is in a balloon shape, the stent is positioned outside the sheath pipe and is in an expansion state, the outer surface of the outer expansion pipe is attached to the inner wall of the stent, and the outer diameter of the outer expansion pipe in the second expansion state is larger than the outer diameter of the sheath pipe;

The inner catheter further comprises an inner-layer expansion tube, an inner-layer connecting tube, a connector, a fixing piece and a handle, wherein the middle-layer expansion tube is sleeved on the outer surface of the inner-layer expansion tube, the middle-layer connecting tube is sleeved on the outer surface of the inner-layer connecting tube, the far end of the inner-layer connecting tube is connected with the inner-layer expansion tube, the far ends of the outer-layer expansion tube, the middle-layer expansion tube and the inner-layer expansion tube are fixedly connected with the connector, the near ends of the outer-layer connecting tube, the middle-layer connecting tube and the inner-layer connecting tube are fixedly connected with the handle, the fixing piece is fixedly arranged on the outer surface of the outer-layer expansion tube and/or the outer-layer connecting tube, the fixing piece is used for fixing the bracket, and the handle is used for driving the sheath tube to move on the outer surface of the inner catheter along the axial direction of the inner catheter;

The outer expansion pipe with outer connecting catheter with the middle level expansion pipe with the middle level connecting catheter encloses second outer lumen, the middle level expansion pipe with the middle level connecting catheter with the inlayer expansion pipe with the inlayer connecting catheter encloses the middle level lumen, the interior pipe still includes second outer valve, middle level valve and medium conveyor, the second outer valve sets up the second outer lumen with between the medium conveyor, the middle level valve sets up the middle level lumen with between the medium conveyor, the medium conveyor is used for passing through the middle level valve to pour into the medium into in the middle level lumen into in the second outer lumen.

2. The stent delivery device of claim 1, wherein the inner catheter further has an initial state, the inner catheter having an outer diameter in the initial state that is less than an outer diameter in the first expanded state.

3. The stent delivery device of claim 1, wherein the inner catheter further has an initial state in which the outer stent tube and the middle stent tube are folded, the outer diameter of the middle stent tube in the first expanded state being greater than the outer diameter of the outer stent tube in the initial state.

4. A stent loading method of the stent delivery device according to any one of claims 1 to 3, comprising:

pressing the stent sleeved on the outer surface of the inner catheter into the lumen of the sheath;

injecting a medium into the lumen of the inner catheter, and expanding the inner catheter to the first expansion state so as to enable the inner catheter to be in a balloon shape, and enabling the outer surface of the inner catheter to be attached to the inner wall of the bracket in a press-holding state.

5. The stent loading method of claim 4, further comprising releasing a medium within a lumen of the inner catheter to place the inner catheter in an initial state.