CN113893062A

CN113893062A - Covered stent

Info

Publication number: CN113893062A
Application number: CN202010641395.9A
Authority: CN
Inventors: 肖本好; 方毅
Original assignee: Shenzhen Xianjian Changtong Medical Co ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2020-07-06
Filing date: 2020-07-06
Publication date: 2022-01-07
Anticipated expiration: 2040-07-06
Also published as: CN113893062B

Abstract

The invention provides a covered stent, which comprises a reticular supporting structure, a first section and a second section, wherein the second section is connected with the near end and/or the far end of the first section; a plurality of windows are formed among the second wave rings, and the first wave rings and the second wave rings form the supporting structure. The second section of the stent graft provided by the embodiment of the invention can not shield the opening of the branch blood vessel, so that the length of the stent graft in the main branch blood vessel does not need to be reduced, and the stent graft has a long enough anchoring area in the main branch blood vessel to ensure that the stent graft has enough anchoring force, thereby avoiding the displacement or internal leakage of the distal end of the stent graft and ensuring good plugging effect.

Description

Covered stent

Technical Field

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

Background

Arterial stenosis or dissection is a disease with high death rate and disability rate at present, and the traditional operation has large trauma, more complications and high death rate. Vascular stents are currently implanted by intraluminal repair to treat such vascular conditions. Generally, a stent is delivered to a target vascular site by a delivery device, and the stent is released and expanded to reconstruct a blood vessel or block a dissection, thereby achieving the purpose of treatment. Endovascular prosthetics of vascular stents have the following advantages: the low-risk means has the advantages of small wound, less complication, high safety, less pain of patients, low intraoperative hemorrhage, short hospitalization time and benefit for high annual disease severity. Generally, in order to isolate the lacerations without affecting the blood supply of the important branch vessels, one or more "chimney" stents are released between the aorta covered stent and the aorta inner wall to form blood flow channels of the important branch vessels. Therefore, the aorta covered stent can cover the artery interlayer laceration or isolate the aortic aneurysm cavity, and can not cover the opening of an important branch blood vessel.

Because of the small overall size of "chimney" stents (stent lumen stents typically do not exceed 20 mm), current "chimney" stents are typically cut or woven. The cutting stent generally adopts a fiber laser to carry out laser cutting on a nickel-titanium tubular material, and the shape required by the stent is achieved through polishing and secondary shaping or multiple shaping, but the stent has the defects of stress concentration, poor fatigue performance, incapability of cutting large-diameter products (limited size), easiness in fracture and the like. The braided stent is generally formed by braiding nickel-titanium linear materials by adopting a mould, and the braided stent has the following defects: in order to ensure the support performance of the stent, the head end and the tail end of the main body of the common stent are mutually wound or hooked, the sheath tube is pushed out again after the product is assembled in the sheath tube, the risk of kinking the head end and the tail end of the support body or integral shortening of the stent exists, and the stent often fails to be normally unfolded or fails to completely cover a preoperative target position to cause operation failure.

In addition, because human blood vessels develop differently, the current chimney stent still has some defects in application:

in order to effectively isolate a diseased region, a woven stent graft is usually used as a chimney stent, however, under the condition that a secondary branch blood vessel is arranged on an important main branch blood vessel, in order to avoid shielding an opening of the secondary branch blood vessel by the stent graft, the implantation depth of the stent graft in the important main branch blood vessel is often reduced, that is, the length of an anchoring region at the far end of the stent graft is reduced, so that the problem of insufficient anchoring force of the stent is brought, and further, the far end of the chimney stent is displaced or leaks inwards, and the plugging effect is poor.

In addition, as shown in fig. 14, for the woven bare stent section 102, there is no connection point between the two

wave rings

1021 and 1022, and they are in a free state, when the wave rings are acted by relative external force, they will be dislocated, where the dislocated distance is a, and a is greater than or equal to 0 and less than or equal to h (h is the wave height of a single wave ring), that is, the bare stent section 102 is shortened, so that the anchoring area of the bare stent section is insufficient.

Disclosure of Invention

In view of the above problems, it is an object of the present invention to provide a stent graft that can have a sufficient anchoring length in the case of implantation into a main branch vessel, and that can not obstruct the opening of the branch vessel. The purpose is realized by the following technical scheme:

the embodiment of the invention provides a covered stent, which comprises a reticular supporting structure, a first section and a second section, wherein the second section is connected with the near end and/or the far end of the first section; a plurality of windows are formed among the second wave rings, and the first wave rings and the second wave rings form the supporting structure.

In an embodiment, the second section includes a hollow-out support section, the hollow-out support section includes a plurality of hollow-out structures, edges of the hollow-out structures are consistent with the waveform edge of the second wave ring, and the hollow-out structures form the window.

In one embodiment, two adjacent second wave coils are fixedly connected through a connecting piece.

In one embodiment, a protective film is wrapped on the surface of the second wave ring, the connecting member and the protective film both comprise polymer materials, and the connecting member and the protective film are fused.

In one embodiment, the stent graft includes a sealing structure disposed at the distal end of the first segment, and the sealing structure at least partially protrudes from the outer surface of the first segment.

In an embodiment, the second section further includes a second coating film, the second coating film covers surfaces of the second wave rings, the second wave rings are fixedly connected through the second coating film, and a plurality of through holes are formed in the second coating film, and the through holes form the window.

In one embodiment, the second coating includes an outer coating and an inner coating, and the outer coating and the inner coating are fused together by heat treatment to fix the second wave ring between the outer coating and the inner coating.

In one embodiment, the stent graft further comprises a third section, the third section is sleeved outside the first section, the distal end of the third section is connected with the outer surface of the first section, and the proximal end of the third section forms an opening facing the proximal end; the third section comprises a third wave ring and a third coating film covering the surface of the third wave ring.

In an embodiment, a diameter of the third wave ring is larger than a diameter of the first wave ring, a wave structure of the first wave ring is substantially the same as a wave structure of the third wave ring, and a wave number of the first wave ring is smaller than the third wave ring.

In an embodiment, the proximal wave circle of the third section and the first wave circle on the first section radially opposite to the proximal wave circle are peak staggered.

The invention has the advantages that:

according to the stent graft of the embodiment of the invention, the stent graft comprises a first section and a second section connected with the far end of the first section, when the stent graft is implanted into a main branch blood vessel, the stent graft can form a blood flow channel of the main branch blood vessel, if a secondary branch blood vessel is arranged on the main branch blood vessel, the second section covers an opening of the secondary branch blood vessel after the stent graft is implanted, but because a window is formed on the second section, the second section can not block the passage of blood flowing from the main branch blood vessel to the secondary branch blood vessel. Therefore, the second section of the stent graft provided by the embodiment of the invention can not shield the opening of the secondary branch blood vessel, so that the length of the stent graft in the primary branch blood vessel does not need to be reduced, the stent graft has a long enough anchoring area in the primary branch blood vessel to ensure that the stent graft has enough anchoring force, and further, the displacement or internal leakage of the distal end of the stent graft is avoided, thereby ensuring a good plugging effect.

Drawings

The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

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

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

FIG. 3 is a schematic diagram of the connection between two adjacent second wave rings according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of the connection of two adjacent second wave rings according to another embodiment of the present invention;

FIG. 5 is a schematic view of a connection of a connector to a wire of a second undulating ring in accordance with one embodiment of the present invention;

FIG. 6 is a schematic diagram illustrating a formation method of a protection film according to an embodiment of the invention;

FIG. 7 is a schematic diagram illustrating a formation method of a protection film according to another embodiment of the present invention;

FIG. 8 is a schematic view of a stent graft according to an embodiment of the present invention released in an aortic arch vessel;

FIG. 9 is a schematic view of a stent graft according to another embodiment of the present invention released in an aortic arch vessel;

FIG. 10 is a schematic view of a stent graft according to another embodiment of the present invention;

FIG. 11 is a schematic view of a stent graft according to yet another embodiment of the present invention;

FIG. 12 is a schematic view of a stent graft according to yet another embodiment of the present invention;

FIG. 13 is a schematic view of a stent graft according to yet another embodiment of the present invention;

FIG. 14 is a schematic diagram of a prior art wave ring structure after shortening; .

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For convenience of description, spatially relative terms, such as "inner", "outer", "lower", "below", "upper", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In the field of interventional medical devices, and in particular for implants (e.g. stents) implanted in the body, the direction of blood inflow is defined as "proximal" and the direction of blood outflow is defined as "distal", and according to this principle the "proximal" and "distal" of any part of the medical device is defined.

Example one

As shown in FIG. 1, one embodiment of the present invention provides a stent graft 100, wherein the stent graft 100 comprises a first section 10 and a second section 20 connected to the distal end of the first section 10. The first segment 10 includes a plurality of first wave rings 11 and a first coating film 12 covering the surface of the first wave rings 11. The second section 20 includes a plurality of second wave rings 21, and a plurality of windows 201 are formed between the plurality of second wave rings 21, and the plurality of windows 201 may allow blood to flow therethrough. The plurality of first wave rings 11 and the plurality of second wave rings 21 each constitute a net-shaped support structure.

A stent graft 100 according to an embodiment of the present invention includes a first segment 10 and a second segment 20 connected to a distal end of the first segment 10. When the stent graft 100 is implanted in a main branch vessel, the stent graft 100 may form a blood flow passageway in the main branch vessel. Because a stent graft requires a certain anchoring force after being implanted into a blood vessel, a certain requirement (for example, not less than 15mm) is imposed on the length of the stent graft, and if a secondary branch blood vessel is present on the main branch blood vessel near the opening of the primary branch blood vessel and the second segment 20 covers the opening of the secondary branch blood vessel after the stent graft 100 is implanted, the second segment 20 does not block the passage of blood from the main branch blood vessel to the branch blood vessel because the window 201 is formed on the second segment 20. Therefore, the second section 20 of the stent graft 100 of the embodiment of the present invention does not obstruct the opening of the branch vessel. Therefore, the length of the stent graft 100 in the main branch vessel does not need to be reduced, so that the stent graft 100 has a sufficiently long anchoring region in the main branch vessel to ensure that the stent graft 100 has sufficient anchoring force, thereby avoiding the displacement or internal leakage of the distal end of the stent graft 100, ensuring good plugging effect and not influencing the blood supply of the secondary branch vessel.

It will be appreciated that in the above embodiments, the second section 20 is attached to the distal end of the first section 10, and in other embodiments, the second section 20 may be attached to the proximal end of the first section 10, for example, when the stent graft of the present invention is implanted to partially cover the opening of other adjacent main branch vessels in the aortic blood vessel, the second section is disposed at the proximal end of the first section and the second section is provided with a window, so that the second section does not obstruct blood flow into the adjacent main branch vessels; alternatively, the second segment 20 may be attached to both the distal and proximal ends of the first segment 10 (as shown in fig. 2) so that the stent graft has sufficient anchoring force within the main branch vessel without obstructing either the opening of the superior branch vessel or the opening of the adjacent main branch vessel. The selection can be made according to the actual development of the blood vessel to be implanted (the position of the branch blood vessel). The above cases are all within the protection scope of the present invention.

In this embodiment, the first coating 12 may be made of PTFE material and includes an inner coating and an outer coating, wherein the outer coating and the inner coating may be fused together by means of heat treatment to fix the first wave ring 11 between the outer coating and the inner coating. As shown in fig. 1, both ends of the first coating 12 are designed to have a petal-shaped structure, that is, both ends of the first coating 12 are wavy, and the wavy edge is consistent with the wavy edge of the first wave ring 11.

As shown in fig. 1, the second section 20 includes a hollow-out support section, and a hollow-out structure on the hollow-out support section forms a window 201, and the hollow-out structure can allow blood to freely pass through. Therefore, under the condition that the hollow stent section covers the opening of the secondary branch blood vessel, blood can freely flow to the secondary branch blood vessel from the main branch blood vessel through the hollow structure.

Referring to fig. 1 and 3, the hollow-out support section includes a plurality of second wave rings 21, and two adjacent second wave rings 21 are fixedly connected by a connecting member 22. When the second section 20 is pulled by external force (blood flow impact, the covered stent 100 is subjected to external force action in the process of being released by a conveyor, etc.), the connecting piece 22 can resist the impact of the external force, so that the two adjacent second wave rings 21 cannot be dislocated, and therefore the hollow stent section cannot be shortened, and the length of the anchoring area of the covered stent 100 cannot be shortened to maintain sufficient anchoring force. In the embodiment, the wave height of the second wave ring 21 is h, wherein the selectable range of the wave height h is not less than 2.5mm and not more than 5.0 mm.

The connection between two adjacent second wave rings 21 can be in the manner shown in fig. 3 and 4. Namely, two adjacent second wave rings 21 are connected in parallel, are not overlapped in the radial direction of the film-coated bracket and are directly fixed through a connecting piece; or two connected second wave rings 21 are connected in a mutual hanging mode, wherein the wave crest of one second wave ring is connected with the wave trough of the other second wave ring. In this embodiment, the surface of the metal wire 211 of the second wave ring 21 is wrapped by the protective film 23 made of a polymer material with good biocompatibility, and the protective film 23 has less irritation to the blood vessel compared with the metal wire. The connecting member 22 fixedly connects the adjacent two second wave rings 21 in a winding manner, and the connecting member 21 is fused with the protective film 23. The connecting member 22 may be made of a polymer material, and may be a wire or a strip. In this embodiment, the connecting member 221 and the protective film 23 may be both PTFE films.

As shown in fig. 5, the connector 22 may be wound on the second wave 21 a plurality of times such that the connector 22 projects radially from the surface of the second section 20. Thereby, the anchoring force between the second section 20 and the blood vessel may be improved. In addition, the increase of the number of winding layers can also improve the connection stability between two adjacent second wave rings 21, thereby improving the capability of resisting external force impact. Specifically, the number of winding layers of the connecting member 221 may be controlled to be between 4 and 10, and in general, one layer of film has a thickness of about 0.1mm, so that the dimension h2 at the connecting member 22 is h1+0.1 n, where h1 is the sum of the wire diameter of the wire of the second wave ring 21 and the thickness of the protective film, and n is the number of winding layers, which may be equal to any integer between 4 and 10.

It will be appreciated that in other embodiments, the connecting member 22 may be a welded structure or a wire wound around two adjacent second wave rings 21. That is, two adjacent second wave rings 21 may be wound together by a wire or directly connected together by welding, so as to realize the connection between two adjacent second wave rings 21.

As shown in fig. 3, the two adjacent second wave rings 21 are connected in a hooking manner, and the coupling member 22 is engaged to obtain a stable connection between the two adjacent wave rings 21, and in addition, the connection is advantageous to form a protruding structure at the connection position to improve the anchoring force between the second section 20 and the blood vessel.

In other embodiments, as shown in fig. 4, two adjacent second wave rings 21 may be butted only in a contact manner, and then connected by a connecting member 22. On this basis, the connection stability between the second wave rings 21 and the protrusion of the connection member 22 from the surface of the second section 20 can also be improved by increasing the number of winding layers of the connection member 221.

For convenient processing and saving the processing time of the covered stent, the plurality of first wave rings and the plurality of second wave rings can be integrally woven, for example, the metal wires are woven, so that the wave crests and the wave troughs of the plurality of first wave rings and the plurality of second wave rings are connected in a mutual hanging mode, and then the first wave rings and the second wave rings are further covered with films or otherwise processed respectively. By adopting the mutual hanging weaving mode, the connection force between the wave rings is stronger, and the integral supporting performance of the covered stent is better.

The protective film 23 wrapped on the surface of the wire 211 of the second wave ring 21 may have 1 to 3 layers, wherein the protective film may be formed by covering the entire surface of the wire 211 (as shown in fig. 6), or formed by winding the surface of the wire 211 with a narrow film 2301 (as shown in fig. 7). After the heat treatment, the protective film 23 is attached to the surface of the wire 211.

Because the second section 20 is a hollow-out stent section, the surface of the metal wire 211 of the second wave ring 21 is wrapped by the protective film 23 with good biocompatibility, so that the biocompatibility of the second section 20 can be improved. The protective film 23 may be fixed to the surface of the wire 211 by a heat treatment. On the other hand, the two adjacent second wave rings 21 are fixed by the connecting member 22 in a winding manner, and the connecting member 22 and the protective film 23 wrapped on the surface of the metal wire 221 are fused together in a heat treatment manner, so that stable connection is formed between the two second wave rings 21, impact of external force is resisted, and dislocation between the two second wave rings 21 is prevented.

The manner of use and the effect of the stent graft of the present invention are illustrated in two specific examples below:

FIG. 8 is a schematic view of the stent graft 100 in one embodiment released in an aortic arch vessel 200. The aortic arch blood vessel 200 includes ascending aorta blood vessel 210, brachiocephalic trunk blood vessel 220, left common carotid artery blood vessel 230, left subclavian artery blood vessel 240, and descending aorta blood vessel 250. Wherein a left vertebral artery 260 branches above the opening adjacent to the left subclavian artery 240. When the main body covered stent 300 is used for treating the lesion of the aortic arch blood vessel 200, the blood flow channel of the left subclavian artery blood vessel 240 needs to be reconstructed so as to ensure the blood supply of the corresponding blood vessel. The main body covered stent 300 can isolate the near-end crevasse or tumor cavity of the aortic dissection, and can complete the patency of the branch blood vessel by matching with the covered stent 100. To ensure that there is sufficient anchoring area and no migration after implantation of the stent graft 100, the anchoring requirement for the left subclavian artery 240 is that the anchoring length be no less than 15mm, i.e., L1 ≧ 15mm as shown in FIG. 8. If the operation is carried out by adopting the full-body tectorial membrane stent, the stent can shield the opening of the left vertebral artery 260, so that the left upper limb is ischemic, and corresponding complications are generated. When the stent graft 100 is used for treatment, the main stent graft 300 is released to a specified position, then the stent graft 100 is positioned, and a proper specification is selected, so that the first section 10 is flush with the edge of the proximal opening of the main stent graft 300 (the proximal section of the stent graft on the first section 10 is closer to the heart than the proximal end of the stent graft of the main stent graft 300), and the proximal end of the second section 20 is closer to the proximal end of the main stent graft 300 than the opening of the left vertebral artery 260, namely the second section 20 can span the opening of the left vertebral artery 260, thereby keeping the blood flow unblocked.

In the embodiment, the first section 10 of the stent graft 100 is attached with the first coating 12, so that the proximal internal leakage can be avoided, the second section 20 is provided with a window, the opening of the left vertebral artery 260 can be prevented from being blocked, the anchoring area of the stent graft is long enough to meet the anchoring condition (L1 is more than or equal to 15mm), and the stent is prevented from being displaced.

As shown in FIG. 9, FIG. 9 is a schematic view of another embodiment of the stent graft 100 released in an aortic arch vessel 400. unlike the previous embodiment, the stent graft 100 is released in reverse, reversing the orientation of the proximal and distal ends of the stent graft 100. Aortic arch blood vessel 400 includes ascending aorta vessel 410, brachiocephalic trunk vessel 420, left common carotid vessel 430, left subclavian artery vessel 440, and descending aorta vessel 450. Wherein the opening distance between the left subclavian artery vessel 440 and the left common carotid artery vessel 430 is within 10 mm. For treating the aortic dissection or aortic aneurysm in the aspect of the aortic arch blood vessel 400, the blood flow path of the left subclavian artery blood vessel 440 needs to be reconstructed, and the main body stent graft 500 can be used for isolating the near-end breach or the aneurysm cavity of the aortic dissection and matching with the stent graft 100 to complete the reconstruction of the branch blood flow. While ensuring that the anchoring length of the distal end of the left subclavian artery 440 is not less than 15mm, the anchoring length of the proximal end of the stent graft is also required to be not less than 15mm, i.e., L2 is not less than 15mm in the illustration. If the operation is performed by adopting the full-coated stent graft, the opening distance between the left subclavian artery vessel 440 and the left common carotid artery vessel 430 is small, and the stent graft can block the opening of the left common carotid artery vessel 430, so that cerebral ischemia is caused, and corresponding complications are generated. When the stent graft 100 is used for treatment, the main body stent graft 500 is released to a designated position, then a proper stent graft 100 is selected, the proximal end of the first section 10 is flush with the edge of the proximal opening of the main body stent graft 500, the internal leakage of a gap can be prevented, the second section 20 can cross the opening of the left common carotid artery blood vessel 430, the second section 20 comprises a hollow section, the blood flow can be kept smooth, and the self anti-shortening structure can prevent the stent from being displaced without being pressed by the main body stent graft 500 to close the proximal end of the second section 20.

In the embodiment, the first section 10 of the stent graft 100 can prevent the distal reflux and internal leakage, and the second section 20 can prevent the adjacent main branch artery from being blocked, and can also meet the anchoring condition (L is more than or equal to 15mm) to prevent the stent from displacing.

Example two

Another embodiment of the present invention provides a stent graft 100, which differs from the first embodiment in that the second section 20 of the present embodiment includes a second cover.

Specifically, the second section 20 includes a plurality of second wave rings 21 and a second coating film covering the surface of the second wave rings 21, and a plurality of through holes are provided on the second coating film, the through holes constituting the windows 201. In this embodiment, the second coating and the first coating 12 may be two parts of a whole coating, i.e., the part of the whole coating located at the first section 10 is the first coating 12, and the part located at the second section 20 is the second coating. A plurality of through holes are formed in the second coating, and the through holes are preferably positioned to avoid the second wave ring, so that the second wave ring is not directly exposed to blood. The through-hole serves as a window 201 for the passage of blood, so that the second section 20 does not obstruct the opening of the branch vessel. It will be appreciated that the through-holes in the second coating may be formed by removing portions of the coating, or by forming cuts in the coating (e.g., cross cuts) but leaving all of the coating. It will be appreciated that the larger the through-hole, the more likely blood will flow into the secondary branch vessel.

The second coating includes an outer coating and an inner coating, which are fused together by heat treatment to fix the second wave ring 21 between the outer coating and the inner coating. Each second wave ring 21 has a relatively fixed positional relationship between different second wave rings 21 through the fusion of the inner-layer coating and the outer-layer coating, so that the adjacent second wave rings 21 are not displaced, and therefore, the stent graft 100 is not shortened due to the action of external force. It is understood that the second coating film of the present invention may correspond to the protective film of the first embodiment.

EXAMPLE III

As shown in FIG. 10, another embodiment of the present invention provides a stent graft 100 that is substantially identical in structure to the first and second embodiments, except that the stent graft 100 further includes a third section 30.

Specifically, the third section 30 includes a plurality of third wave rings 31 and a third coating 32 attached to the surface of the third wave rings 31, and the third section 30 is sleeved on the outer surface of the first section 10 to form a skirt structure outside the first section 10. The distal end of the third section 30 is connected to the outer surface of the first section 10 so as to form an opening at the proximal end towards the proximal end of the first section 10, and the proximal end of the third section 30 does not exceed the proximal end of the first section 10. The stent graft 100 in this embodiment forms part of a double-layered stent graft structure, and the third section 30 can further solve the problem of internal leakage of a "chimney" stent. The first and

second sections

10, 20 of the stent graft 100 are identical in construction to those of the previous embodiments and will not be described further herein. Wherein fig. 10 shows only one third coil at the proximal end of the third section, the remaining third coils being shown.

As shown in fig. 10, the outer diameter of the third section 30 is larger than the outer diameter of the first section 10, and the waveform structure of the first wave ring 11 is substantially the same as the waveform structure of the third wave ring 31. The two wave ring structures are approximately the same, namely the angles of wave height, wave crest or wave trough in the two wave rings are not obviously different. The diameter of the wave turns of the third section 30 is in this embodiment about 2 times the diameter of the first section 10. For the wave rings with the wave shapes having the same size, the larger the diameter, the smaller the radial force of the wave ring, so that when the stent graft 100 shown in fig. 10 is used with the main body stent graft shown in fig. 8 or 9, the third section 30 can be greatly deformed due to extrusion, so that a good sealing effect can be provided, while the first section has a good radial supporting effect and a small deformation degree, so that the size of the proximal opening of the first section can be ensured, and the branched blood can be ensured to sufficiently flow into the stent graft 100.

In this embodiment, in order to avoid that the coating of the proximal portion of the third section 30 is adhered to the outer surface coating of the first section 10 and then the proximal end of the third section 30 is difficult to unfold, it is preferable that the proximal end wave ring of the third section 30 (i.e., the third wave ring 31 closest to the proximal end) and the first wave ring of the first section 10 radially opposite to the proximal end wave ring of the third section 30 are distributed in a staggered peak manner, that is, after the stent graft is compressed, the coating between two adjacent wave peaks on the first section 10 and the first wave ring of the third section 30 radially opposite to the proximal end wave ring is opposite to the wave peak on the third section 30. More preferably, the wave number of the proximal wave ring of the third section 30 is not an odd number or an even number, i.e. the number of peaks or troughs of a single wave ring, at the same time as the wave number of the first wave ring on the first section 10 radially opposite to the proximal wave ring of the third section 30. In order to achieve the radial supporting force of the wave ring, in the present embodiment, the wave number of the third wave ring 31 of the third section 30 is greater than that of the first wave ring 11 of the first section 10, and preferably, the wave number of the third wave ring 31 is 6 to 12, and the wave number of the first wave ring 11 is 5 to 8.

It will be appreciated that to facilitate deployment of the third section, in other embodiments, the peaks of the proximal bead of the third section may also be provided as bare peaks, i.e. the peaks of the proximal bead of the third section are not covered by a film. Therefore, when the covered stent is compressed, the exposed wave crests are directly contacted with the covering film on the outer surface of the first section, adhesion among the covering films cannot occur, and the third section is easier to expand.

Example four

As shown in FIG. 11, the stent graft of the present embodiment has substantially the same structure as the stent graft of the first embodiment, except that the outer-layer coating of the first coating 12 of the present embodiment includes a plurality of coating strips 121 (of which the inner-layer coating is not shown). Specifically, the plurality of first wave rings and the plurality of second wave rings of the stent graft of the present embodiment are formed by integrally weaving, that is, adjacent wave rings are connected by means of a peak-valley hook. A plurality of tectorial membrane areas 121 intercross and form a plurality of blank regions, a plurality of blank regions are relative with crest-trough hook department of two adjacent first ripples circle 11 to make crest-trough hook department surface exposed, thereby two adjacent first ripples circle can take place relative axial displacement, make first section 10 of tectorial membrane support can adapt to the vascular crooked, thereby compliance is better when the tectorial membrane support is implanted main branch blood vessel, also more stable after the implantation.

The outer tectorial membrane of the first section 10 of the covered stent of this embodiment adopts the mode in tectorial membrane area to carry out the tectorial membrane completely for the equal activity in crest-trough hook department of first ripples circle, thereby the whole compliance of first section is better. In other embodiments, the movable portion may be partially suspended in the peak-to-valley, for example, only the peak-to-valley interconnection of the movable first loop may be provided near the distal end of the second segment, or the movable segment may be provided in segments along the length of the first segment.

It is understood that, as shown in fig. 12, in other embodiments, the plurality of coating bands 121 may be coated in a circumferentially surrounding manner, that is, the coating bands 121 cover the wave rod of the first wave ring, and are coated circumferentially around the first wave ring, and the width of the coating bands is smaller than the height of the first wave ring, so as to ensure that the coating bands 121 avoid the wave crest and the wave trough of the first wave ring when coating.

The first segment 10 of this embodiment is axially movable between adjacent first wave turns to better accommodate vessel morphology. Meanwhile, because the plurality of second wave rings of the second section 20 are fixedly connected, the whole covered stent is ensured not to be excessively shortened after the first wave rings move axially, and the anchoring capability of the covered stent is ensured.

EXAMPLE five

As shown in FIG. 13, the stent graft of the present embodiment has substantially the same structure as the stent graft of the fourth embodiment, except that the distal end portion of the first section 10 of the stent graft of the present embodiment further comprises a sealing structure 40. Specifically, the seal structure 40 is provided on the portion of the distal end of the first segment 10 that is connected to the second segment 20. The sealing structure 40 is a sealing membrane disposed circumferentially around the distal end of the first segment 10 such that the sealing structure 40 at least partially protrudes from the outer surface of the first segment 10.

It will be appreciated that in other embodiments, the sealing structure 40 may also be a suture sewn around the shank of the first wave ring at the distal most end of the first segment 10, i.e., the first wave ring and the edge of the first cover film are reinforced with the suture while serving to increase the outer diameter of the distal end portion of the first segment.

It should be understood that the sealing structure of the present embodiment is suitable for the stent graft of other embodiments of the present invention, and the detailed description thereof is omitted here.

The sealing structure 40 is arranged at the far end part of the first section, so that the sealing effect of the far end of the first section 10 can be further improved, and the internal leakage of blood after flowing out of the window of the second section 20 can be avoided.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A stent graft comprises a supporting structure of a net shape, and is characterized by further comprising a first section and a second section connected with the near end and/or the far end of the first section, wherein the first section comprises a plurality of first wave rings and a first coating film covering the surfaces of the first wave rings, the second section comprises a plurality of second wave rings, and every two adjacent second wave rings are fixedly connected; a plurality of windows are formed among the second wave rings, and the first wave rings and the second wave rings form the supporting structure.

2. The stent graft of claim 1, wherein the second section comprises a hollowed-out stent section comprising a plurality of hollowed-out structures, wherein edges of the hollowed-out structures coincide with the wavy edges of the second wave ring, and the hollowed-out structures form the window.

3. The stent graft of claim 2, wherein two adjacent second wave rings are fixedly connected by a connector.

4. The stent graft as recited in claim 3, wherein a protective film is wrapped on the surface of the second wave ring, the connecting member and the protective film both comprise polymer materials, and the connecting member and the protective film are fused.

5. The stent graft of claim 1, wherein the stent graft comprises a sealing structure disposed at the distal end of the first segment, and wherein the sealing structure at least partially protrudes from the outer surface of the first segment.

6. The stent-graft of claim 1, wherein the second section further comprises a second coating, the second coating covers the surfaces of the second plurality of wave rings, the second plurality of wave rings are fixedly connected by the coating, and the second coating is provided with a plurality of through holes, and the through holes form the window.

7. The stent graft of claim 6, wherein the second cover comprises an outer cover and an inner cover, the outer cover and the inner cover being fused together by heat treatment to secure the second wave ring between the outer cover and the inner cover.

8. The stent graft of any one of claims 1-7, wherein the stent graft further comprises a third section that is disposed about the exterior of the first section, wherein a distal end of the third section is coupled to an exterior surface of the first section, and wherein a proximal end of the third section defines a proximally-facing opening; the third section comprises a third wave ring and a third coating film covering the surface of the third wave ring.

9. The stent graft of claim 8, wherein the third wave ring has a wave ring diameter that is greater than the first wave ring diameter, and wherein the wave structure of the first wave ring is substantially the same as the wave structure of the third wave ring, and wherein the wave number of the first wave ring is less than the third wave ring.

10. The stent graft of claim 8, wherein the proximal wave loop of the third segment is off-peak with respect to a first wave loop on the first segment radially opposite the proximal wave loop.