CN110652377A

CN110652377A - Covered stent and manufacturing method thereof

Info

Publication number: CN110652377A
Application number: CN201810713900.9A
Authority: CN
Inventors: 夏顺; 叶猛; 刘梦钦; 郭芳; 袁振宇; 朱清
Original assignee: Shanghai Minimally Invasive Heart Vein Medical Technology Co Ltd
Current assignee: Shanghai Hongmai Medical Technology Co., Ltd
Priority date: 2018-06-29
Filing date: 2018-06-29
Publication date: 2020-01-07

Abstract

The invention provides a covered stent and a manufacturing method thereof, which are applied to the field of implanted medical instruments. The covered stent comprises a framework, a framework covering film and an inner layer covering film, wherein the framework covering film is arranged on the framework, the framework covering film and the framework are mutually bonded together, the inner layer covering film is arranged in an inner cavity defined by the framework covering film and the framework, the inner layer covering film comprises N sections of bonding sections and M sections of separating sections, N is larger than or equal to 2, M is equal to N-1, the bonding sections and the separating sections are alternately arranged along the axial interval of the framework covering film and are connected into a whole, the bonding sections are respectively bonded with the framework covering film and the framework together, and a hollow layer is formed between the separating sections and the framework covering film. The inner wall of the covered stent can be smooth by additionally arranging the inner layer of the covered membrane in the inner cavity of the common covered stent.

Description

Covered stent and manufacturing method thereof

Technical Field

The invention relates to the field of implanted medical instruments, in particular to a covered stent and a manufacturing method thereof.

Background

In the field of implantable medical devices, ePTFE-coated stents have been widely recognized for use in recent years, with advantages including excellent biocompatibility and superior lubricity. The indications of this type of stent-graft include peripheral vascular embolization, aortic dissection, aortic aneurysm pseudoramis, and aortic ulcer and branch penetrating ulcer. The implantation operation of the covered stent greatly reduces the operation death rate and postoperative complications, and simultaneously can lighten the operation trauma and lead the recovery of patients to be quicker. The mechanism of the implantation operation is that the covered stent is delivered to a diseased region through a special delivery system and then is expanded to prop open a blood vessel blocked by thrombus or isolate a tumor body from blood, so that the risk of death caused by large bleeding due to aneurysm rupture is reduced, or the compression of the tumor body on surrounding tissues and organs is reduced.

In the field of peripheral blood vessels, most of pathological changes are vascular embolism, the diameter of a target blood vessel is smaller and is generally less than 10mm, the anatomical morphology is tortuous, and a covered stent needs to have higher flexibility. By compliant, it is meant that the shape of the stent graft can conform to the shape of the blood vessel, changing as the shape of the blood vessel changes. The good flexibility can ensure that the wall sticking condition of the covered stent and the blood vessel is good, and no gap is left between the outer wall of the covered stent and the blood vessel.

However, in the case of a stent graft having high flexibility, the stent graft is susceptible to wrinkling due to deformation of the stent graft. Specifically, the high flexibility of the covered stent enables the skeleton to generate corresponding deformation along with the rise of thrombus in the blood vessel, so that the outer wall of the skeleton is better attached to the blood vessel with pathological changes, but the covered stent is folded due to the fact that the covered stent has the inner cavity which is not smooth any more but is in an irregular shape. The irregular morphology of the lumen of the stent graft tends to alter blood flow in the lumen of the blood vessel, for example, creating vortices and the like in the blood vessel. And the change of blood flow in the lumen of the blood vessel easily causes thrombus to be generated in the inner cavity of the covered stent, thereby causing restenosis in the covered stent. In the clinical application of the stent graft, the problem of restenosis of the stent graft has been the focus of clinical research.

Therefore, there is an urgent need for an improved stent graft to smooth the lumen of the stent graft.

Disclosure of Invention

The invention aims to provide a covered stent and a manufacturing method thereof, which aim to solve the problem that the inner cavity of the existing covered stent is not smooth.

In order to solve the technical problems, the invention provides a covered stent which comprises a framework, a framework covering film and an inner layer covering film, wherein the framework covering film is arranged on the whole framework, the framework covering film and the framework are adhered together, the inner layer covering film is arranged in an inner cavity of the covered stent and comprises an N-section adhering section and an M-section separating section, N is larger than or equal to 2, M is equal to N-1, the adhering section and the separating section are alternately arranged along the axial direction of the framework covering film and are connected into a whole, the adhering section is adhered with the framework covering film, and a hollow layer is formed between the separating section and the framework covering film.

Optionally, the inner-layer covering membrane covers the entire inner cavity of the covered stent.

Optionally, the axial length of the inner-layer coating is smaller than the axial length of the covered stent, and both ends of the inner-layer coating are not overlapped with both ends of the covered stent.

Optionally, the number N of the bonding segments is 2, and the number M of the separation segments is 1.

Optionally, the number N of the bonding segments is greater than or equal to 3.

Optionally, the skeleton covering film includes an outer covering film and a middle covering film, the outer covering film is arranged on the whole outer circumferential surface of the skeleton, the middle covering film is arranged on the whole inner circumferential surface of the skeleton, and the outer covering film, the middle covering film and the skeleton are mutually bonded in pairs.

Optionally, the skeleton is disposed in a film layer of the skeleton coating film.

Optionally, the skeleton tectorial membrane includes outer tectorial membrane, outer tectorial membrane sets up on the whole outer peripheral face of skeleton, just outer tectorial membrane with the skeleton bonds each other together.

Optionally, the inner-layer coated membrane is a PU membrane, an UHMWPE membrane, a PTFE membrane, or an ePTFE membrane.

The invention also provides a manufacturing method of the covered stent, the covered stent comprises a framework, a framework covering film and an inner layer covering film, the inner layer covering film comprises N sections of bonding sections and M sections of separation sections, wherein N is more than or equal to 2, M is equal to N-1, two ends of the inner layer covering film are respectively provided with one bonding section, the bonding sections and the separation sections are alternately arranged along the axial direction of the framework covering film, and the manufacturing method of the covered stent comprises the following steps: arranging the framework covering film on the framework, and mutually bonding the framework covering film and the framework together; and arranging the inner-layer film in the inner cavity of the covered stent, and bonding the bonding section and the framework film together.

The invention provides a covered stent and a manufacturing method thereof, which have the following beneficial effects:

since the skeleton coating and the skeleton are connected to each other, when the shape of the skeleton changes, the shape of the skeleton coating bound by the skeleton also changes according to the change in the shape of the skeleton. The inner-layer film is arranged in an inner cavity defined by the film-covered stent, the bonding section of the inner-layer film is bonded with the framework film and the framework, the bonding sections at two ends of the inner-layer film are also bonded with the framework film and the framework, the separation section of the inner-layer film and the middle-layer film define a hollow layer, the bonding section and the separation section are alternately arranged along the axial direction of the framework film, and the bonding section and the separation section are sequentially connected into a whole, so that the separation section of the inner-layer film and the middle-layer film are separated from each other, and the separation section of the inner-layer film is not bound by the framework. When the shape of the framework changes, the inner-layer coating is not completely bound by the framework, the shape of the inner-layer coating does not change along with the shape change of the framework, namely the inner-layer coating is not easy to form wrinkles under the influence of the framework, and relatively smooth transition is formed between a fixed end (the bonding position of the inner-layer coating and the outer-layer coating, and the middle-layer coating and the framework) and a stress point (the force application point of the framework on the inner-layer coating), so that the shape in the cavity is closer to a circular tube shape, and the risk of restenosis of the covered stent caused by the wrinkles on the inner wall of the covered stent after the covered stent is implanted into a blood vessel can be reduced. Particularly, after the covered stent is implanted into a blood vessel, the inner wall of the inner covering membrane can still keep smooth under the scouring of blood flow, or the folds formed by the bending and folding of the framework to the inner wall of the inner covering membrane can be reduced or eliminated.

Drawings

FIG. 1 is a cross-sectional view of a stent graft according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view of a stent graft according to a first embodiment of the present invention after bending;

FIG. 3 is a schematic representation of an embodiment of the stent graft of the present invention implanted in a blood vessel without release;

FIG. 4 is a schematic representation of a stent graft according to one embodiment of the present invention after release after implantation in a blood vessel;

FIG. 5 is a cross-sectional view of a stent graft according to a second embodiment of the present invention;

FIG. 6 is a cross-sectional view of a stent graft according to a third embodiment of the present invention;

FIG. 7 is a cross-sectional view of a stent graft in accordance with a fifth embodiment of the present invention.

Description of reference numerals:

100-covered stent; 110-a framework; 120-skeleton film covering; 121-outer layer coating; 122-middle layer coating; 130-inner layer film covering; 131-an adhesive segment; 132-a separation section; 140-a hollow layer; 150-stress point; 160-blood vessels.

Detailed Description

As described in the background art, the existing covered stent has the problem that the inner cavity is not smooth, and the application provides a covered stent and a manufacturing method of the covered stent. On the basis of a common covered stent, an artificial blood vessel is additionally arranged in the inner cavity of the covered stent, namely, a layer of covered membrane is additionally arranged in the inner cavity of the covered stent, two ends of the layer of covered membrane are fixed with the original covered stent, and the middle part of the layer of covered membrane is separated from the original covered stent and is similar to the artificial blood vessel. Because the added layer of film is separated from the original covered stent, when the original covered stent generates wrinkles due to the bending of the framework, the added layer of film does not generate wrinkles therewith, but forms relatively smooth transition between the fixed positions at the two ends of the added layer of film and the middle stress point, so that the shape of the covered stent is closer to a circular tube shape, and the inner wall of the covered stent is smooth.

The stent graft and the method for manufacturing the stent graft according to the present invention will be described in further detail with reference to the accompanying drawings and specific examples. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Example one

The present embodiments provide a stent graft. Fig. 1 is a cross-sectional view of a stent graft according to a first embodiment of the present invention, and referring to fig. 1, the stent graft 100 includes a stent graft 110, a stent graft 120, and an inner-layer stent graft 130, and the stent graft 120 includes an outer-layer stent graft 121 and an intermediate-layer stent graft 122. The outer layer coating 121 is disposed on the entire outer circumferential surface of the frame 110, the middle layer coating 122 is disposed on the entire inner circumferential surface of the frame 110, and the outer layer coating 121, the middle layer coating 122, and the frame 110 are bonded to each other two by two. The inner coating film 130 is disposed in the lumen of the stent graft 100, and specifically, the inner coating film 130 is disposed on the entire inner wall of the middle coating film 122. The inner layer coating 130 includes N bonding segments 131 and M separating segments 132, where N is 2 and M is N-1 in this embodiment, and two bonding segments 131 are respectively disposed at two ends of the inner layer coating 130. The bonding sections 131 and the separation sections 132 are alternately arranged along the axial direction of the skeleton coating 120, and the bonding sections 131 and the separation sections 132 are sequentially connected into a whole. The bonding segments 131 at both ends of the inner layer film 130 are bonded to the middle layer film 122. The part of the inner layer coating 130 which is not bonded to the middle layer coating 122 and the middle layer coating 122 together enclose a hollow layer 140, i.e. the separation section 132 of the inner layer coating 130 and the middle layer coating 122 together enclose a hollow layer 140. That is, in the present embodiment, the bonding sections 131 are disposed at both ends of the inner coating film 130, and the separation section 132 is located in the middle of the inner coating film 130.

In the present embodiment, since the outer layer coating 121 provided on the entire outer circumferential surface of the bobbin 110 and the middle layer coating 122 provided on the entire inner circumferential surface of the bobbin 110 are coupled to the bobbin 110 in pairs, when the shape of the bobbin 110 is changed, the shapes of the outer layer coating 121 and the middle layer coating 122 bound by the bobbin 110 are also changed according to the change in the shape of the bobbin 110. The inner layer coating 130 is disposed in the inner cavity surrounded by the middle layer coating 122, the bonding sections 131 at two ends of the inner layer coating 130 are respectively bonded with the middle layer coating 122, and the separation section 132 of the inner layer coating 130 and the middle layer coating 122 surround a hollow layer 140, so that the separation section 132 of the inner layer coating 130 and the middle layer coating 122 are separated from each other, and the separation section 132 of the inner layer coating 130 is not bound by the framework 110. Therefore, when the shape of the framework 110 changes, because the inner layer coating 130 is not completely bound by the framework 110, the shape of the inner layer coating 130 does not change along with the change of the shape of the framework 110, that is, the inner layer coating 130 is not easily wrinkled under the influence of the framework 110, but a relatively smooth transition is formed between the fixed end (where the inner layer coating 130 is bonded to the middle layer coating 122, that is, the two bonding segments 131 in the embodiment) and the force point (the point of application of the framework 110 to the inner layer coating 130), so that the shape in the cavity is closer to a circular tube shape. Particularly after the stent graft 100 is implanted in a blood vessel, the inner wall of the inner coating 130 may remain smooth under the influence of blood flow, or wrinkles formed on the inner wall of the inner coating 130 by bending and folding the stent graft 110 may be reduced or eliminated. Thereby reducing the risk of restenosis of the stent graft 100 after implantation of the stent graft 100 in a blood vessel due to wrinkles on the inner wall of the stent graft 100.

Fig. 2 is a cross-sectional view of a stent graft 100 according to a first embodiment of the present invention, as shown in fig. 2, after the shape of the framework 110 is changed, because the inner coating 130 is not completely bound by the framework 110, the shape of the inner coating 130 does not change with the change of the shape of the framework 110, but forms a relatively smooth transition between the fixed end (i.e., the bonding segment 131) and the force point 150, so that the shape in the lumen is closer to a circular tube shape.

The existing covered stent which is good in flexibility and has no obvious wrinkles in an inner cavity is exposed through the top point of the framework, so that the influence of the framework on the shape of the covered stent during bending is reduced, and the risk of restenosis of the covered stent can be reduced. However, the covered stent can only use the mesh-bound delivery system of the invention, and cannot be compatible with the delivery system in the market at present, and the skeleton in the covered stent is exposed, and the skeleton is easy to generate inflammatory reaction when directly contacting with the vessel wall. In addition, the technical difficulty of realising such a mesh-bound conveyor system is great, requiring the use of special materials and corresponding machines for weaving the corresponding meshes, which is costly. Compared with the covered stent, the covered stent in the embodiment does not change the original framework 110 of the covered stent, and only the inner layer covering membrane 130 is arranged in the inner cavity of the framework 110, so that a special delivery system is not needed for installation, the compatibility with a common delivery system is good, and the framework 110 of the covered stent 100 in the embodiment is not exposed, so that the inflammatory reaction caused by the exposure of the framework 110 can be avoided. In addition, the inner wall of the inner coating 130 of the stent graft 100 of the present embodiment can be kept smooth, so that the inner wall of the stent graft 100 can be kept smooth while having good flexibility.

The stent graft 100 is easy to realize, improves the practicability of the stent graft 100, and is beneficial to promoting the application of the stent graft 100 in the field of implanted medical devices. The scope of use of the stent graft 100 may include all thoraco-abdominal aortic stents as well as small stents for arterial and peripheral branches.

The stent graft 100 has a simple structure and strong operability, and does not need to increase extra cost. Compared with the stent graft 100 on the market, the stent graft 100 in the embodiment maximally maintains the characteristic of smooth lumen shape of the stent graft 100.

The frame 110 of the stent graft 100 may be a corrugated frame made of NiTi or pure titanium. The material of the frame 110 may also be stainless steel, cobalt-chromium alloy, nickel-titanium alloy, etc.

The outer layer coating film 121, the middle layer coating film 122, and the inner layer coating film 130 may be PU (polyurethane, PU for short), UHMWPE (ultra high molecular weight polyethylene), PTFE (PTFE), or ePTFE (expanded Poly fluoro ethylene) films.

The embodiment also provides a manufacturing method of the covered stent 100, which specifically comprises the following steps:

first, the outer-layer coating 121 is disposed on the entire outer circumferential surface of the frame 110 (which may be a waveform frame 110 made of NiTi wires), the middle-layer coating 122 is disposed on the entire inner circumferential surface of the frame 110, and the outer-layer coating 121, the middle-layer coating 122 and the frame 110 are bonded to each other two by two to manufacture a complete double-layer coated stent.

Next, an inner-layer coating 130 is disposed in an inner cavity formed by the middle-layer coating 122, so that the inner-layer coating 130 is disposed on the entire inner wall of the middle-layer coating 122, and the two bonding sections 131 of the inner-layer coating 130 are bonded to the middle-layer coating 122, respectively, thereby forming the three-layer stent graft 100. For example, when the stent graft 100 has a length of 100mm and a diameter of 10mm, the length of the adhesive segment 131 is 5mm and the length of the separation segment 132 is 90 mm. The length of the bonding segment 131 refers to the length of the bonding segment 131 along the axial direction of the stent graft 100, the length of the bonding segment 131 along the axial direction of the stent graft 110, and the length of the bonding segment 131 along the axial direction of the stent graft 120. Of course, the above dimensions are only for example and do not limit the technical solution of the present invention.

Typically, the stent graft 100 is manufactured and then installed in a delivery device, after which the stent graft 100 is implanted in the vessel 160 via the delivery system.

Fig. 3 is a schematic view showing a stent graft according to an embodiment of the present invention implanted in a blood vessel without release, fig. 4 is a schematic view showing the stent graft according to an embodiment of the present invention after release from the blood vessel, and referring to fig. 3 and 4, the stent graft 100 is implanted in the blood vessel 160 to open the stenosed blood vessel 160, thereby healing the stenosis of the blood vessel 160. However, the blood vessel wall which is propped by the stent cannot be completely flat, the plaque and the thrombus still slightly bulge, the metal framework can generate corresponding deformation along with the bulge of the thrombus due to the high flexibility of the stent, the outer wall of the stent is better attached to the blood vessel with pathological changes, and meanwhile, the structural design of the three-layer film-covered stent 100 ensures the smoothness of the inner cavity of the stent, so that the blood flows smoothly in the stent.

Example two

The present embodiments provide a stent graft. The stent graft in the embodiment is different from the stent graft in the first embodiment in that the number N of the bonding segments is more than or equal to 3. The separation sections and the middle layer coating film are encircled to form a plurality of hollow layers, and the hollow layers are alternately arranged along the axial direction of the framework.

Fig. 5 is a cross-sectional view of a stent graft according to a second embodiment of the present invention, referring to fig. 5, a plurality of bonding segments 131 of the inner coating 130 are respectively bonded to the middle coating 122, a plurality of separation segments 132 and the middle coating 122 enclose a plurality of hollow layers 140, and the plurality of hollow layers 140 are alternately arranged along an axial direction of the stent graft 110.

Because the inner-layer coating 130 is soft and cannot be bent to form, the inner-layer coating 130 and the middle-layer coating 122 are alternately adhered together in multiple sections in the region away from the near end and the far end, so that the inner-layer coating 130 is adhered more firmly and can better conform to the bent form of the framework 110 when the framework 110 is bent, and because the inner-layer coating 130 and the middle-layer coating 122 are still not adhered together in multiple sections, the problem that the inner wall of the inner-layer coating 130 is wrinkled due to the bending of the framework 110 can be reduced or eliminated by the inner-layer coating 130.

first, the outer coating 121 is disposed on the entire outer circumferential surface of the stent 110 (which may be a waveform stent 110 made of NiTi filaments), the middle coating 122 is disposed on the entire inner circumferential surface of the stent 110, and the outer coating 121, the middle coating 122 and the stent 110 are bonded to each other two by two to manufacture a complete double-layered stent.

Next, an inner-layer coating 130 is disposed in the inner cavity formed by the middle-layer coating 122, such that the inner-layer coating 130 is disposed on the entire inner wall of the middle-layer coating 122, and the bonding section 131 of the inner-layer coating 130 is bonded to the middle-layer coating 122, thereby forming the three-layer stent graft 100. For example, when the stent graft 100 has a length of 114mm and a diameter of 10mm, the length of the adhesive segments 131 provided at both ends of the inner coating 130 is 5mm, the length of the adhesive segments 131 provided between both ends of the inner coating 130 is 1mm, and the interval between two adjacent segments of the adhesive segments 131 is 20 mm. The length of the bonding segment 131 refers to the length of the bonding segment 131 along the axial direction of the stent graft 100, the length of the bonding segment 131 along the axial direction of the stent graft 110, and the length of the bonding segment 131 along the axial direction of the stent graft 120. Of course, the above dimensions are only for example and do not limit the technical solution of the present invention.

EXAMPLE III

The present embodiments provide a stent graft. Fig. 6 is a cross-sectional view of a stent graft according to a third embodiment of the present invention, and referring to fig. 6, the difference between the stent graft 100 according to the third embodiment and the stent graft 100 according to the first embodiment is that in the present embodiment, the inner-layer coating 130 is disposed on a region of the stent graft 110 away from the proximal end of the stent graft 110 and away from the distal end of the stent graft 110, that is, the length of the inner-layer coating 130 in the axial direction is smaller than the length of the stent graft 100, and both ends of the inner-layer coating 130 are not overlapped with both ends of the stent graft 100, and the bonding sections 131 at both ends of the inner-layer coating 130 are bonded to the middle-layer coating 122, respectively, and the separation section 132 of the inner-layer coating 130 and the middle-layer coating 122 together enclose a hollow layer 140.

In this embodiment, the inner coating 130 is not disposed on the inner wall of the entire middle coating 122, so that the problem of the volume increase (the outer diameter increase after crimping) of the stent graft 100 caused by the disposition of the inner coating 130 can be reduced, and the inner wall of the middle coating 122 can be utilized to dispose the inner coating 130, and only the bonding sections 131 at the two ends of the inner coating 130 are bonded to the middle coating 122, and the separation section 132 of the inner coating 130 is separated from the inner wall of the middle coating 122, so that the risk of the inner coating 130 wrinkling under the deformation of the framework 110 can be eliminated or reduced, and the inner wall of the stent graft 100 can be kept smooth.

Next, the inner-layer coating 130 is disposed in the inner cavity formed by the middle-layer coating 122, so as to be disposed only in the region of the middle-layer coating 122 away from the proximal end of the middle-layer coating 122 and away from the distal end of the middle-layer coating 122, and the bonding segments 131 of the inner-layer coating 130 are bonded to the middle-layer coating 122, respectively, thereby forming the three-layer stent graft 100. For example, when the stent graft 100 has a length of 100mm and a diameter of 10mm, an inner coating 130 having an axial length of 70mm is disposed in the lumen formed by the middle coating 122, and the bonding segments 131 at both ends of the inner coating 130 have a length of 5 mm. The length of the bonding segment 131 refers to the length of the bonding segment 131 along the axial direction of the stent graft 100, the length of the bonding segment 131 along the axial direction of the stent graft 110, and the length of the bonding segment 131 along the axial direction of the stent graft 120. Of course, the above dimensions are only for example and do not limit the technical solution of the present invention.

Example four

The present embodiments provide a stent graft. The stent graft in the present embodiment is different from the stent graft in the first embodiment in that the skeleton coating includes only the outer coating.

The stent graft 100 includes a scaffold 110, an outer cover 121, and an inner cover 130. The outer layer coating 121 is provided on the entire outer circumferential surface of the bobbin 110, and the outer layer coating 121 and the bobbin 110 are bonded to each other. The inner coating film 130 is disposed in the inner cavity defined by the frame 110. The inner coating film 130 is provided over the entire bobbin 110. The bonding segments 131 at both ends of the inner layer film 130 are respectively bonded with the middle layer film 122. The separation section 132 of the inner coating film 130 and the outer coating film 121 together enclose a hollow layer 140.

Since the outer layer coating 121 provided on the entire outer circumferential surface of the bobbin 110 and the bobbin 110 are connected to each other, when the shape of the bobbin 110 is changed, the shape of the outer layer coating 121 bound by the bobbin 110 is also changed according to the change in the shape of the bobbin 110. The inner coating 130 is disposed in the inner cavity surrounded by the framework 110, the bonding sections 131 at two ends of the inner coating 130 are respectively bonded with the middle coating 122, and the separation section 132 of the inner coating 130 and the outer coating 121 surround a hollow layer 140, so that the separation section 132 of the inner coating 130 is separated from the outer coating 121 and the framework 110, and the separation section 132 of the inner coating 130 is not bound by the framework 110. When the shape of the framework 110 changes, because the inner coating film 130 is not completely bound by the framework 110, the shape of the inner coating film 130 does not change along with the shape change of the framework 110, that is, the inner coating film 130 is not easy to form wrinkles under the influence of the framework 110, but forms relatively smooth transition between the fixed end and the stress point, so that the shape in the cavity is closer to a round pipe shape, and the risk of restenosis of the stent graft 100 caused by the wrinkles on the inner wall of the stent graft 100 after the stent graft 100 is implanted into a blood vessel can be reduced.

first, the outer-layer coating 121 is disposed on the entire outer circumferential surface of the stent graft 110 (which may be a corrugated stent graft made of NiTi wire), and the outer-layer coating 121 and the stent graft 110 are bonded to each other to produce a complete single-layered stent graft.

Secondly, an inner-layer coating 130 is arranged in the inner cavity formed by the framework 110, so that the inner-layer coating 130 is arranged on the whole inner wall of the framework 110, and bonding sections 131 at two ends of the inner-layer coating 130 are bonded with the outer-layer coating 121 and the framework 110, thereby forming a two-layer covered stent 100. For example, when the stent graft 100 has a length of 100mm and a diameter of 10mm, the inner coating 130 and the outer coating 121 may be bonded to each other in a region 5mm apart from each of the proximal and distal ends of the stent graft 110, so that the inner coating 130 and the outer coating 121 are separated from each other in a region of about 90mm in the middle of the stent graft 100. Of course, in this embodiment, the stent graft 100 may have other dimensions, and is not limited thereto.

EXAMPLE five

The present embodiments provide a stent graft. FIG. 7 is a cross-sectional view of a stent graft in a fifth embodiment of the present invention, and referring to FIG. 7, the difference between the stent graft 100 in the present embodiment and the stent graft 100 in the fourth embodiment is that the stent graft 100 in the present embodiment has only one layer of the skeleton coating 120, and the skeleton 110 is disposed in a film layer of the skeleton coating 120.

Since the skeleton 110 is provided in the film layer of the skeleton coating 120, when the shape of the skeleton 110 is changed, the shape of the skeleton coating 120 bound by the skeleton 110 is also changed according to the change in the shape of the skeleton 110. The inner layer coating 130 is disposed in the inner cavity surrounded by the framework 110, the bonding sections 131 at two ends of the inner layer coating 130 are respectively bonded with the framework coating 120, and the separation section 132 of the inner layer coating 130 and the framework coating 120 surround a hollow layer 140, so that the separation section 132 of the inner layer coating 130 and the framework coating 120 are separated from each other, and the separation section 132 of the inner layer coating 130 is not bound by the framework 110. When the shape of the framework 110 changes, because the inner coating film 130 is not completely bound by the framework 110, the shape of the inner coating film 130 does not change along with the shape change of the framework 110, that is, the inner coating film 130 is not easy to form wrinkles under the influence of the framework 110, but forms relatively smooth transition between the fixed end and the stress point, so that the shape in the cavity is closer to a round pipe shape, and the risk of restenosis of the stent graft 100 caused by the wrinkles on the inner wall of the stent graft 100 after the stent graft 100 is implanted into a blood vessel can be reduced.

In addition, since the skeleton 110 is disposed in the film layer of the skeleton coating film 120, the skeleton 110 may be completely provided with the coating film on the surface thereof, so that the risk of the skeleton coating film 120 falling off the skeleton 110 may be reduced.

firstly, raw material wires are sprayed on the framework 110 to form a layer of framework covering film 120, and the framework 110 is arranged in a film layer of the framework covering film 120, so that a complete single-layer stent is manufactured. Wherein the raw material filaments may be PU, UHMWPE, ePTFE or PTFE.

Secondly, an inner-layer coating 130 is arranged in the inner cavity formed by the framework 110, so that the inner-layer coating 130 is arranged on the whole inner wall of the framework 110, and the bonding sections 131 at two ends of the inner-layer coating 130 are bonded with the framework coating 120 respectively, thereby forming the two-layer coated stent 100. For example, when the stent graft 100 has a length of 100mm and a diameter of 10mm, the bonding segments 131 at both ends of the inner layer coating 130 may have a length of 5mm, and the bonding segments 131 at both ends of the inner layer coating 130 and the skeleton coating 120 may be bonded to each other such that the inner layer coating 130 and the skeleton coating 120 are separated from each other in a region of about 90mm in the middle of the stent graft 100. Of course, in this embodiment, the stent graft 100 may have other dimensions, and is not limited thereto.

In the above embodiments, the skeleton is in a shape of a mesh tube, and in a schematic cross-sectional view of the skeleton along the axial direction, the skeleton is not continuous, specifically refer to fig. 1, 5, 6, and 7.

It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

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

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. The covered stent is characterized by comprising a framework, a framework covering film and an inner layer covering film, wherein the framework covering film is arranged on the whole framework, the framework covering film and the framework are bonded together, the inner layer covering film is arranged in an inner cavity of the covered stent, the inner layer covering film comprises N sections of bonding sections and M sections of separating sections, N is larger than or equal to 2, M is equal to N-1, the bonding sections and the separating sections are alternately arranged along the axial direction of the framework covering film and are connected into a whole, the bonding sections are bonded with the framework covering film, and a hollow layer is formed between the separating sections and the framework covering film.

2. The stent graft of claim 1, wherein the inner cover membrane covers the entire lumen of the stent graft.

3. The stent graft of claim 1, wherein the inner cover has an axial length less than the axial length of the stent graft and wherein both ends of the inner cover do not coincide with both ends of the stent graft.

4. A stent graft as in any one of claims 1 to 3, wherein the number of adhesive segments N is 2 and the number of detached segments M is 1.

5. A stent graft as claimed in any one of claims 1 to 3, wherein the number N of adhesive segments is 3 or more.

6. A stent graft as defined in any one of claims 1 to 3, wherein the stent graft includes an outer-layer coating film and a middle-layer coating film, the outer-layer coating film is provided on the entire outer circumferential surface of the stent graft, the middle-layer coating film is provided on the entire inner circumferential surface of the stent graft, and the outer-layer coating film, the middle-layer coating film and the stent graft are bonded to each other two by two.

7. A stent graft as defined in any one of claims 1 to 3, wherein the scaffold is disposed in a membrane layer of the scaffold membrane.

8. A stent graft as defined in any one of claims 1 to 3, wherein the stent graft includes an outer coating film provided over the entire outer circumferential surface of the stent graft, and the outer coating film and the stent graft are bonded to each other.

9. The stent graft of any one of claims 1 to 3, wherein the inner cover membrane is a PU membrane, an UHMWPE membrane, a PTFE membrane, or an ePTFE membrane.

10. A method for manufacturing a stent graft according to any one of claims 1 to 9, wherein the stent graft comprises a stent graft, a stent graft and an inner-layer coating, the inner-layer coating comprises N sections of bonding sections and M sections of separation sections, wherein N is greater than or equal to 2, M is equal to N-1, two ends of the inner-layer coating are respectively provided with a bonding section, and the bonding sections and the separation sections are alternately arranged along an axial direction of the stent graft, the method for manufacturing the stent graft comprises:

arranging the framework covering film on the framework, and mutually bonding the framework covering film and the framework together; and the number of the first and second groups,

and arranging the inner-layer film in the inner cavity of the covered stent, and bonding the bonding section and the framework film together.