CN114712034A

CN114712034A - Covered stent

Info

Publication number: CN114712034A
Application number: CN202110006848.5A
Authority: CN
Inventors: 朱永锋; 徐健伟
Original assignee: Shanghai Minimally Invasive Heart Pulse Medical Technology Group Co ltd
Current assignee: Shanghai Minimally Invasive Heart Pulse Medical Technology Group Co ltd
Priority date: 2021-01-05
Filing date: 2021-01-05
Publication date: 2022-07-08
Also published as: WO2022148308A1

Abstract

The invention relates to a covered stent. This covered stent includes: the stent comprises a metal stent, an inner-layer film and at least one outer-layer film; the inner-layer film is arranged on the metal support, the outer-layer film is arranged on the outer side of the inner-layer film in a surrounding mode, at least one clamping cavity is formed between the inner-layer film and the at least one outer-layer film, and the outer-layer film can be spread. This covered stent can be applied to in the treatment field of the abdominal aorta tumour body, the inner chamber of inlayer tectorial membrane can make the normal flow of abdominal aorta blood flow, the outer tectorial membrane of enclosing the inlayer tectorial membrane outside of locating can strut in order to form the tight wainscot of tumor cavity wall or the tight wainscot of arterial blood vessel wall, branch's blood vessel on the abdominal aorta tumour body of can shutoff, block the blood flow refluence in the branch's blood vessel, leak in the prevention II type, avoid the abdominal aorta tumour body to further enlarge, need not secondary intervention, need not carry out the operation again promptly, thereby avoid the patient to bear bigger risk.

Description

Covered stent

Technical Field

The invention relates to the technical field of medical instruments, in particular to a covered stent.

Background

The endovascular intervention treatment is a minimally invasive treatment mode, and the survival probability of patients with vascular diseases who cannot tolerate surgical operations is improved. The covered stent is one of important implants for endovascular intervention treatment, and II-type endoleaks can occur after an abdominal aneurysm patient repairs an endovascular aneurysm, so that the aneurysm body is further enlarged, and life risk is brought to the patient. The current mainstream treatment for abdominal aorta type II endoleaks is a secondary intervention, i.e. requiring another operation, which puts the patient at greater risk.

Disclosure of Invention

In view of the above, it is necessary to provide a stent graft that addresses the problem of type II endoleaks in a stent graft after an abdominal aneurysm patient has undergone intraluminal aneurysm repair.

A stent graft, comprising: the stent comprises a metal stent, an inner-layer film and at least one outer-layer film;

the inner-layer film is arranged on the metal support to form an inner cavity which is through along the axial direction of the metal support, the outer-layer film is arranged around the outer side of the inner-layer film, at least one clamping cavity is formed between the inner-layer film and the at least one outer-layer film, and the outer-layer film can be unfolded.

In one embodiment, the inner layer coating film has a preset leakage amount of 300 (ml/cm)²/min)-1000(ml/cm²/min)。

In one embodiment, a thrombogenic agent or fluff is disposed within the clip cavity.

In one embodiment thereof, the stent graft further comprises: a filler disposed in the nip chamber, the filler being for spreading apart the outer cover film.

In one embodiment, the outer-layer coating film surrounds the periphery of the blocking part of the inner-layer coating film, wherein the near end and the far end of the outer-layer coating film are respectively fixed on the blocking part in a sealing manner;

the outer-layer coating is made of flexible materials, and the surface area of the outer-layer coating is larger than that of the blocking portion.

In one embodiment, the material of the inner layer covering film and/or the outer layer covering film is at least one of PET, ePTFE or Tpu.

In one embodiment, the proximal end and the distal end of the outer covering film are fixed on the outer side of the inner covering film by sewing or hot melting.

In one embodiment, at least one visceral artery blood supply site is arranged on the inner film;

the number of the clamping cavities is more than or equal to 2, the clamping cavities are sequentially distributed along the direction from the near end to the far end of the inner-layer tectorial membrane, and the adjacent two clamping cavities are separated from the far side and the near side of the corresponding visceral artery blood supply position.

In one embodiment, the number of the outer-layer covering films is greater than or equal to 2, and the clamping cavity is formed between each outer-layer covering film and each inner-layer covering film.

the number of the outer-layer covering film and the number of the clamping cavities are both 1, the outer-layer covering film is provided with at least one blood supply window, the positions, located around the blood supply window, in the outer-layer covering film are fixed on the inner-layer covering film, and the blood supply window is communicated with the corresponding visceral artery blood supply position.

In one embodiment thereof, the stent graft comprises a main stent graft and a branch stent graft connected to a distal end of the main stent graft;

the far end of the outer layer film is fixed on the inner layer film of the branch film-covered stent.

As above-mentioned covered stent can be applied to the treatment field of the abdominal aortic aneurysm body, the inner chamber of inlayer tectorial membrane can make the normal flow of abdominal aorta blood flow, the outer tectorial membrane of locating the inlayer tectorial membrane outside can strut in order to form the closely waited facial features of tumor cavity wall or the closely waited facial features of arterial blood vessel wall, can block the branch blood vessel on the abdominal aorta aneurysm body, can block the blood flow reflux in the branch blood vessel, leak in the prevention II type, avoid the abdominal aorta aneurysm body to further enlarge, need not secondary intervention, do not need to carry out the operation again promptly, thereby avoid the patient to bear bigger risk.

Drawings

FIG. 1 is a schematic structural view of a stent graft according to an embodiment of the present invention;

FIG. 2 is a schematic view of a stent graft according to one embodiment of the present invention;

FIG. 3 is a schematic view of the mounting of a stent graft according to another embodiment of the present invention;

FIG. 4 is a schematic view of the mounting of a stent graft according to another embodiment of the present invention;

FIG. 5 is a schematic view of the mounting of a stent graft according to another embodiment of the present invention.

Wherein the reference numerals in the drawings are as follows:

100. a metal bracket; 110. a bare metal stent; 200. coating the inner layer with a film; 300. coating a film on the outer layer; 310. coating a film on the outer layer of the near end; 320. covering a film on the outer layer of the far end; A. a clamp cavity; 400. a branch vessel; 500. the iliac artery; 500a, iliac bifurcation point; 600. the visceral artery; f1, closely adhering the tumor cavity wall; f2, the artery vessel wall is tightly attached to the surface.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1, fig. 1 shows a schematic structural diagram of a stent graft according to an embodiment of the present invention, and the stent graft provided by the embodiment of the present invention includes: a metal stent 100, an inner-layer coating 200 and at least one outer-layer coating 300; the inner-layer coating 200 is arranged on the metal stent 100 to form an inner cavity which is through along the axial direction of the metal stent 100; the outer-layer coating 300 is arranged around the outer side of the inner-layer coating 200, at least one clamping cavity A is formed between the inner-layer coating 200 and at least one outer-layer coating 300, and the outer-layer coating 300 can be opened.

The stent graft according to the embodiment of the present invention is applicable to the field of treatment of an abdominal aortic aneurysm, and the outer coating 300 can be spread to close off branch vessels 400 (see fig. 2 to 5) on the aortic aneurysm, and the branch vessels 400 do not mean important visceral arteries such as the double renal artery, the celiac trunk, and the superior mesenteric artery, but mean branch vessels that do not cause serious complications even if blood is not passed through the human body. In addition, the lumen of the inner graft 200 serves to allow normal blood flow in the abdominal aorta.

As an example, as shown in fig. 1 to 5, the metal stent 100 is made of a biocompatible metal material such as nitinol, stainless steel, etc. Wherein, the metal bracket 100 comprises a plurality of support rings arranged at intervals; the support ring can be arranged into a ring type structure, a wave type structure and the like. Optionally, as shown in fig. 1, a bare metal stent 110 is disposed on the proximal end of the metal stent 100, and the bare metal stent 110 is used for anchoring of the stent graft. Wherein, the bare metal stent 110 may be configured in a ring type, a wave type, etc.

The covered stent can be applied to the field of treatment of abdominal aortic aneurysm bodies, the inner cavity of the inner-layer covered membrane 200 can enable the blood flow of abdominal aorta to normally flow, the outer-layer covered membrane 300 arranged around the outer side of the inner-layer covered membrane 200 can be stretched to form a tumor cavity wall close-fitting surface or an arterial blood vessel wall close-fitting surface, so that the branch blood vessel 400 on the abdominal aortic aneurysm body can be blocked, the blood flow backflow in the branch blood vessel 400 can be blocked, the type II internal leakage can be prevented, the abdominal aortic aneurysm body is prevented from being further expanded, the secondary intervention is not needed, i.e. the operation is not needed again, and therefore the patient is prevented from bearing greater risks.

In some embodiments of the invention, the outer cover 300 is capable of forming a tumor cavity wall cling surface F1 when expanded. When the outer-layer coating 300 is filled in the aneurysm cavity of the abdominal aortic aneurysm body, the closely attaching surface F1 of the aneurysm cavity wall is closely attached to the inner wall of the aneurysm cavity of the abdominal aortic aneurysm body, so that the branch blood vessel 400 can be covered, the blood flow in the branch blood vessel 400 can be blocked, the outer-layer coating 300 can be closely contacted with the near end and the far end of the abdominal aortic aneurysm body, and a certain blocking effect can be achieved on I-type internal leakage caused by the fact that the near end and the far end of the covered stent are not closely attached to the abdominal aortic aneurysm body. Proximal in this context means the end closer to the heart and distal means the end further away from the heart.

Two examples are given of how to distract the outer cover film 300:

in item (1), in some embodiments of the present invention, the inner-layer coating 200 has a predetermined amount of leakage, so that blood flowing in the inner-layer coating 200 can flow through the inner-layer coating 200 into the lumen a between the outer-layer coating 300 and the inner-layer coating 200, thereby spreading the outer-layer coating 300. Due to leakage of the inner-layer coating 200 in a short period after operation, blood in the inner-layer coating 200 can slowly enter the clamping cavity A between the outer-layer coating 300 and the inner-layer coating 200 through the inner-layer coating 200, and then the outer-layer coating 300 is opened, so that the purpose of blocking the branch blood vessel 400 is achieved.

Alternatively, the preset leakage amount is 300 (ml/cm)²/min)-1000(ml/cm²Min), for example, 300 (ml/cm) may be set²/min)、400(ml/cm²/min)、500(ml/cm²/min)、600(ml/cm²/min)、700(ml/cm²/min)、800(ml/cm²/min)、900(ml/cm²/min)、1000(ml/cm²Min), etc. So set up the scope of predetermineeing the leakage volume, both can guarantee that the blood flow in the inlayer tectorial membrane 200 smoothly enters into the double-layered chamber A between inlayer tectorial membrane 200 and the outer tectorial membrane 300, in time struts outer tectorial membrane 300 and then the shutoff branch blood vessel 400, also can guarantee that the blood flow in the inlayer tectorial membrane 200 can slowly flow into in the double-layered chamber A, guarantees to form the thrombus in the double-layered chamber A long-term, prevents continuously that II type internal leakage from taking place. Wherein the inner layer coating film 200 may beIs an ePTFE (Expanded Polytetrafluoroethylene) film, a PET (Polyethylene terephthalate) single/multiple filament film or other film with the leakage amount of 300 (ml/cm)²/min)～1000(ml/cm²Coating film in the range of/min).

Optionally, a thrombogenic agent or fluff is placed in the lumen A between the outer and

inner cover films

300, 200. Wherein the thrombosis promoting agent is a chemical agent containing components for promoting thrombosis such as natural polysaccharide gum and Apelin-17.

In other embodiments of the present invention, the stent graft further comprises: and a filler placed in the clamping cavity A, wherein the filler is used for expanding the outer coating 300. Implanting the covered stent into an abdominal aortic aneurysm body, then injecting filler into the cavity A between the outer covered stent 300 and the inner covered stent 200 through the filling window on the outer covered stent 300, further spreading the outer covered stent 300, and then plugging the filling window on the outer covered stent 300.

Optionally, the filler is silica gel. The silica gel has the characteristic of changeable shape, so that the outer-layer coating 300 can be filled in tumor bodies with different structures, the outer-layer coating 300 can be ensured to effectively block blood flow backflow in the branch blood vessel 400, and effective relieving effect on I-type internal leakage caused by the fact that the near end and the far end of the coated stent are not tightly attached to the blood vessel can be achieved. Of course, in some embodiments of the present invention, the filler may be provided as other filler materials that may be used for intervention.

As shown in fig. 1 to 5, in some embodiments of the present invention, the outer coating film 300 surrounds the periphery of the barrier portion of the inner coating film 200, and the proximal and distal ends of the outer coating film 300 are hermetically fixed to the proximal and distal ends of the barrier portion, respectively; the outer-layer coating 300 is made of flexible materials, the surface area of the outer-layer coating 300 is larger than that of the blocking part, and the surface area of the outer-layer coating 300 is equal to or larger than that of the inner wall of the tumor cavity of the abdominal aortic aneurysm body, so that the outer-layer coating can be fully attached to the inner wall of the tumor cavity. The blocking portion of the inner-layer coating 200 refers to a portion of the inner-layer coating 200 that separates the lumen of the inner-layer coating 200 from the lumen a, that is, a portion of the inner-layer coating 200 that corresponds to the outer-layer coating 300 in the axial direction of the metal stent 100, and may refer to a circumferential surface of the inner-layer coating 200 at the proximal end and the distal end, or a circumferential surface of the inner-layer coating 200 at a portion other than the proximal end and the distal end, and functions to block the lumen of the inner-layer coating 200 and the lumen a between the inner-layer coating 200 and the outer-layer coating 300. Thus, the outer-layer coating 300 does not need to be made of an elastic material, that is, the outer-layer coating 300 does not need to be expanded, so that the outer-layer coating 300 can be expanded by ensuring blood flow under self-minute pressure, and the material of the outer-layer coating 300 does not need to be specifically limited. It can be understood that the outer layer coating 300 is a flexible material, i.e. a soft polymer material with good biocompatibility, which can deform under the action of force, and thus is in a drooping state when not being stretched, and can be erect when being subjected to an external force.

In some embodiments of the present invention, the material of the inner cover film 200 and/or the outer cover film 300 is at least one of PET, ePTFE, or Tpu (Thermoplastic polyurethane elastomer rubber). The outer coating film 300 formed of the above materials also had a certain amount of leakage, approximately 300 (ml/cm)²/min)-1000(ml/cm²Min), but the flow rate and the flow speed from the inner-layer coating film 200 to the clamping cavity A between the inner-layer coating film 200 and the outer-layer coating film 300 are too low, so that part of the fluid cannot leak from the outer-layer coating film 300 to the tumor cavity of the abdominal aortic aneurysm body, the leakage amount is very small even if the fluid leaks, the influence on the human body cannot be generated, the leakage can be ignored, and the leakage cannot occur due to endothelialization of the coating film material about one month after the operation. Here, the cavity a formed between the outer layer coating 300 and the inner layer coating 200 is a closed space, that is, there is no leak in both the outer layer coating 300 and the inner layer coating 200 except for a leak due to a predetermined leak amount.

Optionally, the inner-layer coating film 200 is fixed to the metal stent 100 by sewing or hot-melting; the proximal and distal ends of the outer layer coating 300 are fixed to the outer side of the inner layer coating 200 by sewing or heat-melting, respectively. It is understood that the inner-layer coating film 200 is integrally connected to the metal stent 100, i.e., coated on the metal stent 100. Alternatively, the inner cover film 200 is positioned on the inside or outside of the metal stent 100, and the outer cover film 300 is positioned on the outside of the metal stent 100.

In some embodiments of the invention, at least one visceral artery supply site is provided on the inner cover film 200; the number of the clamping cavities A is more than or equal to 2, the clamping cavities A are sequentially distributed along the direction from the near end to the far end of the inner-layer coating 200, and two adjacent clamping cavities A are separated from the far side and the near side of the corresponding visceral artery blood supply position. The visceral artery blood supply site is used for supplying blood to the visceral artery 600 such as the double renal artery, the celiac trunk, and the superior mesenteric artery. Thus, the stent graft can ensure normal blood supply of the visceral artery 600 on the premise of blocking the blood backflow in the branch vessel 400, thereby avoiding causing serious complications. Optionally, a blood-through window is opened on the blood supply site of the internal artery of the inner-layer covering film 200. Preferably, an embedded branch embedded at the blood through window is arranged in the inner-layer covering film 200 and used for installing a branch blood vessel stent which is used for supplying blood to the visceral artery.

Alternatively, the number of the outer-layer coating films 300 is greater than or equal to 2, and a clamping cavity a is formed between each outer-layer coating film 300 and the inner-layer coating film 200. The number of the outer layer coating films 300 is the same as the number of the cavities a, that is, one outer layer coating film 300 constitutes one cavity a.

In other embodiments of the present invention, as shown in fig. 3-5, at least one visceral artery blood supply site is provided on the inner cover membrane 200; the number of the outer-layer tectorial membrane 300 and the clamping cavity A is 1, at least one blood supply window is arranged on the outer-layer tectorial membrane 300, the part of the outer-layer tectorial membrane 300, which is positioned around the blood supply window, is fixed on the inner-layer tectorial membrane 200, and the blood supply window is communicated with the corresponding blood supply position of the visceral artery.

Alternatively, the outer-layer coating 300 is fixed to the inner-layer coating 200 by heat fusion or sewing at a position around the blood supply window.

In some embodiments of the invention, the stent graft comprises a main stent graft and a branch stent graft connected to a distal end of the main stent graft; the distal end of the outer cover 300 is secured to the inner cover 200 of the branched stent graft. It should be noted that the branch stent graft is used for supplying blood to the iliac artery. Therefore, the abdominal aortic aneurysm bodies positioned at different positions of the abdomen can be treated, so that the application range of the covered stent is expanded. It is understood that a main stent graft refers to the portion of the stent graft that is not bifurcated, and a branch stent graft refers to the portion of the stent graft that is bifurcated.

Alternatively, the distal end of the outer cover 300 is fixed to the proximal end of the inner cover 200 of the branched covered stent, or to the middle portion of the inner cover 200 of the branched covered stent, or to the distal end of the inner cover 200 of the branched covered stent. The middle portion of the inner cover 200 of the branched stent graft refers to a portion of the inner cover 200 of the branched stent graft that is located between the proximal end and the distal end.

Optionally, the outer cover 300, when expanded, can form an arterial vessel wall apposition face F2 (see fig. 3-5). When the outer-layer tectorial membrane 300 is opened, the close attaching surface F2 of the artery vessel wall can be tightly attached to the inner wall of the iliac artery 500, and the I-shaped internal leakage caused by the untight attaching of the distal end of the tectorial membrane stent and the iliac artery 500 can be prevented.

The number and the distribution position of the outer layer coating 300 are related to the position relationship among the proximal end of the branch coating stent, the branch blood vessel 400 and the visceral artery 600, and will be described with reference to fig. 2 to 5:

(1) as shown in fig. 2, when the proximal end of the branch stent graft coincides with the iliac bifurcation 500a and the abdominal aortic aneurysm does not involve the visceral artery 600, the number of the outer layer stents 300 is one and the proximal end is disposed around the outer side of the inner layer stent graft 200 of the main stent graft and the distal end is disposed around the proximal end of the branch stent graft to cover the branch vessel 400. It is noted that the outer cover 300 shown in fig. 2, when expanded, has its outer surface forming the lumenal wall abutment F1.

When the inner-layer covering film 200 has a certain leakage amount, due to leakage in a short period after the operation of the inner-layer covering film 200, blood flow from top to bottom in fig. 2 can slowly enter the cavity a between the inner-layer covering film 200 and the outer-layer covering film 300 through the inner-layer covering film 200, so that the outer-layer covering film 300 is unfolded until the tumor cavity of the whole abdominal aortic aneurysm body is filled, and the blood flow can cover the branch blood vessel 400 on the abdominal aortic aneurysm body, thereby blocking blood flow backflow in the branch blood vessel 400 and preventing type ii internal leakage, and can also play a certain role in blocking type I internal leakage caused by the fact that the near end and the far end of the covered stent are not tightly attached to the aortic blood vessel, and meanwhile, due to the slow blood flow rate, thrombus can be formed in the cavity a between the inner-layer covering film 200 and the outer-layer covering film 300, and the type ii internal leakage can be continuously prevented.

(2) As shown in fig. 3, when the proximal end of the branch stent graft is located above the iliac bifurcation 500a and the abdominal aortic aneurysm does not involve the visceral artery 600, the number of the outer layer stents 300 is one and the proximal end is enclosed outside the inner layer stent graft 200 of the main stent graft and the distal end is enclosed at a position between the proximal end of the branch stent graft and the iliac bifurcation 500 a. It should be noted that, when the outer cover 300 shown in fig. 3 is spread, the dotted line is the upper and lower boundary lines, the outer surface located above the boundary line constitutes the aneurysm cavity wall attaching surface F1, and the outer surface located below the boundary line constitutes the arterial blood vessel wall attaching surface F2.

Similarly, when the inner layer coating 200 has a certain leakage amount, then under the effect of blood flow, the outer layer coating 300 expands to fill the tumor cavity of the whole abdominal aortic aneurysm body and cover the branch blood vessels 400, and gradually generates thrombus in the clamping cavity a formed between the inner layer coating 200 and the outer layer coating 300, so that type II internal leakage can be continuously prevented at near and far periods; meanwhile, the device also has a certain blocking effect on I-type internal leakage.

(3) As shown in fig. 4, when the proximal end of the branch stent graft is located above the iliac bifurcation 500a, the abdominal aortic aneurysm affects the visceral artery 600, and the branch vessels 400 are located at the distal and proximal sections of the visceral artery 600, the number of the outer coatings 300 is two, namely, the proximal outer coating 310 and the distal outer coating 320, the proximal outer coating 310 surrounds the portion of the main stent graft located above the visceral artery 600 to cover the corresponding branch vessel 400, the proximal end of the distal outer coating 320 surrounds the portion between the proximal end of the branch stent graft and the visceral artery 600, and the distal end surrounds the portion between the proximal end of the branch stent graft and the iliac bifurcation 500 a. It is noted that the proximal outer cover 310 shown in FIG. 4, when expanded, has its outer surface forming the lumenal wall abutment F1; when the distal outer cover 320 shown in fig. 4 is expanded, the dotted lines represent the upper and lower boundary lines, and the outer surface above the boundary line forms the aneurysm cavity wall attachment surface F1, and the outer surface below the boundary line forms the arterial blood vessel wall attachment surface F2.

The covered stent with the structure can prevent II-type internal leakage; meanwhile, the proximal outer layer coating 310 and the distal outer layer coating 320 gradually expand and cling to the inner wall of the aneurysm cavity of the abdominal aortic aneurysm body and the blood vessel wall of the iliac artery, so that I-type endoleak can be prevented.

(4) As shown in fig. 5, when the proximal end of the branch stent graft is located above the iliac bifurcation 500a, the abdominal aortic aneurysm affects the visceral artery 600, and the branch blood vessel 400 is located on both sides of the visceral artery 600 and below the proximal end of the branch stent graft, the number of the outer coatings 300 is two, that is, the proximal outer coating 310 and the distal outer coating 320, the proximal outer coating 310 is disposed around the position between the proximal end of the branch stent graft and the visceral artery 600, and the distal outer coating 320 is disposed around the position between the visceral artery 600 and the iliac bifurcation 500 a. It is noted that the proximal outer cover 310 shown in FIG. 5, when expanded, has its outer surface forming the arterial vessel wall abutment F2.

The covered stent with the structure can prevent II-type internal leakage; meanwhile, as the distal outer-layer coating 320 gradually expands and clings to the inner wall of the iliac artery, I-shaped internal leakage caused by the untight joint of the distal end of the coated stent and the blood vessel can be prevented.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A stent graft, comprising: a metal stent (100), an inner layer coating (200) and at least one outer layer coating (300);

the inner-layer coating (200) is arranged on the metal support (100) to form an inner cavity which is axially communicated along the metal support (100), the outer-layer coating (300) is arranged on the outer side of the inner-layer coating (200), at least one clamping cavity (A) is formed between the inner-layer coating (200) and the at least one outer-layer coating (300), and the outer-layer coating (300) can be propped open.

2. The stent graft as claimed in claim 1, wherein the inner layer of the cover (200) has a predetermined amount of leakage, and the predetermined amount of leakage is 300 (ml/cm)²/min)-1000(ml/cm²/min)。

3. The stent graft as recited in claim 1, wherein the lumen (A) is filled with a thrombogenic agent or villus.

4. The stent graft of claim 1, further comprising: a filler placed in the nip (A) for spreading the outer cover (300).

5. The stent graft as recited in any one of claims 1 to 4, wherein the outer layer of the cover membrane (300) surrounds the barrier portion of the inner layer of the cover membrane (200), and the proximal and distal ends of the outer layer of the cover membrane (300) are respectively fixed on the barrier portion in a sealing manner;

the outer-layer coating (300) is made of flexible materials, and the surface area of the outer-layer coating (300) is larger than that of the blocking part.

6. The stent graft of any one of claims 1-4, wherein the inner and/or outer cover (200, 300) is at least one of PET, ePTFE, or Tpu.

7. The stent graft as claimed in any one of claims 1 to 4, wherein the proximal and distal ends of the outer cover (300) are fixed to the outer side of the inner cover (200) by sewing or heat-fusing.

8. The stent graft as set forth in any one of claims 1-4, wherein the inner cover (200) has at least one visceral artery supply site disposed thereon;

the number of the clamping cavities (A) is more than or equal to 2, the clamping cavities (A) are sequentially distributed along the direction from the near end to the far end of the inner-layer covering film (200), and the adjacent clamping cavities (A) are separated from the far side and the near side of the corresponding visceral artery blood supply position.

9. The stent graft of claim 8, wherein the number of the outer cover membranes (300) is greater than or equal to 2, and the clamping cavity (A) is formed between each outer cover membrane (300) and the inner cover membrane (200).

10. The stent graft as set forth in any one of claims 1-4, wherein the inner cover (200) has at least one visceral artery supply site disposed thereon;

the number of the outer-layer covering film (300) and the number of the clamping cavities (A) are both 1, at least one blood supply window is arranged on the outer-layer covering film (300), the part, located on the periphery of the blood supply window, in the outer-layer covering film (300) is fixed on the inner-layer covering film (200), and the blood supply window is communicated with the corresponding visceral artery blood supply position.

11. The stent graft of any one of claims 1-4, wherein the stent graft comprises a main stent graft and a branch stent graft connected to a distal end of the main stent graft;

the far end of the outer-layer tectorial membrane (300) is fixed on the inner-layer tectorial membrane (200) of the branch tectorial membrane stent.