CN113876467B

CN113876467B - Covered stent

Info

Publication number: CN113876467B
Application number: CN202111487656.7A
Authority: CN
Inventors: 朱清; 朱永锋; 徐健伟; 奚利峰; 王哲恺; 刘金宏
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: 2021-12-08
Filing date: 2021-12-08
Publication date: 2022-04-15
Anticipated expiration: 2041-12-08
Also published as: WO2023104001A1; CN113876467A; CN114432001A

Abstract

The invention provides a covered stent, which comprises a stent body and a covering film, wherein the covering film is arranged on the surface of the stent body, the stent body comprises a main stent part and two branch stent parts, the two branch stent parts and the main stent part are fixedly connected with the covering film and form a Y-shaped structure, the stent body comprises a plurality of annular stent sections which are sequentially arranged at intervals in the axial direction, and the main stent part comprises a near-end sealing area, a main body area and a transition area which are sequentially arranged from a near end to a far end; the outer diameter of the transition area is sequentially reduced from the near end to the far end; the body regions have the same outer diameter; the outer diameter of the proximal end of the transition region is the same as the outer diameter of the main body region; the proximal sealing zone comprises a proximal sealing stent section, the transition zone comprises a transition stent section, and the body zone comprises a body stent section; the maximum length of the wave rod of the near-end sealing support section is smaller than that of the wave rod of the main body support section; so configured, improve the compliance of tectorial membrane support to reduce interior hourglass and the risk of aversion.

Description

Covered stent

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a covered stent.

Background

Vascular intervention treatment is used as a micro-traumatic treatment mode, and survival probability is improved for vascular disease patients who cannot tolerate surgical operations. There are many vascular bifurcations in the human body, and the lesion area of some aneurysms or dissections may involve the vascular bifurcations and their branches. Taking the abdominal aorta as an example, the distal end of the abdominal aorta bifurcates into the two lateral iliac arteries. In case of abdominal aortic aneurysm or dissection, in a conventional vascular interventional therapy, a main stent (placed at an abdominal aortic lesion) and branch stents (placed at bilateral iliac artery lesions) are spliced in vivo in a lesion region to reconstruct a blood flow channel, and particularly when the lesion is affected to the iliac artery, the treatment method is more effective. The main body support mostly adopts a barb design, the barb punctures the blood vessel to anchor, but the treatment method needs 3 independently formed supports, the operation cost is increased, the splicing among the supports also increases the risk of internal leakage of the spliced part, and simultaneously, the operation time is prolonged, which is not favorable for patients. At present, a very small amount of integrated bracket products exist, but the products are integrally woven, so that the clamping size is large, the flexibility is poor, the inner leakage risk is high, and the defects of long-term displacement and the like exist.

Therefore, there is a need for a novel stent graft to overcome the problems of the prior art stents for treating diseased regions involving vessel bifurcations and branches.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention aims to provide a covered stent, which can improve the flexibility of the covered stent with branches, reduce the holding size of the covered stent and reduce the risks of internal leakage and long-term displacement.

In order to achieve the above and other related objects, the present invention provides a stent covered with a membrane, comprising a stent body and a membrane, wherein the membrane is arranged on the surface of the stent body, the stent body comprises a main stent part and branch stent parts, the two branch stent parts and one main stent part are both fixedly connected with the membrane and form a Y-shaped structure, and the stent body comprises a plurality of annular stent sections which are sequentially arranged at intervals in the axial direction;

the main body support part comprises a near end sealing area, a main body area and a transition area which are sequentially arranged from a near end to a far end; the body regions have the same outer diameter; the outer diameter of the transition area is sequentially reduced from the near end to the far end; the outer diameter of the proximal end of the transition region is the same as the outer diameter of the body region;

optionally, the stent section comprises a proximal sealing stent section, a transition stent section, a main body stent section and a branch stent section; the proximal sealing zone comprises the proximal sealing stent segment, the transition zone comprises the transition stent segment, and the body zone comprises the body stent segment;

the maximum length of the wave bars of the proximal seal carrier section is less than the length of the wave bars of the main body carrier section.

Optionally, the stent graft further comprises a reinforcing rib fixedly connected with the stent graft, and the reinforcing rib extends along the axial direction of the main stent section;

the near end of strengthening rib set up in on the main part district, the distal end of strengthening rib set up in the near end of transition district, the strengthening rib can restrict main part support portion is upwards retracted in the axial.

Optionally, the length of the reinforcing rib is 1% -80% of the axial length of the main body region.

Optionally, the distal ends of the reinforcing ribs are disposed on the peaks of the first of the transition leg segments at the proximal end of the transition zone, and/or the proximal ends of the reinforcing ribs are disposed on the first of the main leg segments at the proximal end of the main body zone.

Optionally, the proximal seal zone comprises at least one high proximal seal carrier segment and at least one high proximal seal carrier segment;

the at least one high-proximal end sealing support section and the at least one high-proximal end sealing support section are arranged at intervals in the axial direction of the main body support part and are arranged in an aligned mode in the circumferential direction of the main body support part;

said at least one heightened proximal seal holder section is disposed at a proximal-most end of said proximal seal zone;

at least one high wave trough is arranged between any two adjacent low wave troughs in the at least one high-proximal sealing bracket section.

Optionally, main part support portion still includes naked section, naked section includes an annular stent section, the distal end of naked section with tectorial membrane fixed connection, stretch out in the proximal end axial of naked section the tectorial membrane, naked section is configured to carry out the anchoring with the vascular wall laminating after expanding, be provided with back release structure on the naked section for release after with the conveyer cooperation in order to realize tectorial membrane support.

Optionally, a groove structure is arranged on the bare section, and a developing part is arranged in the groove structure.

Optionally, the groove structure includes a first groove structure and a second groove structure, the length of the first groove structure is greater than the length of the second groove structure, the first groove structure and the second groove structure are disposed on different wave bars of the bare section, and the lower edge of the first groove structure is flush with the lower edge of the second groove structure, so that the lower edge of the developing component coincides with the proximal edge of the coating film.

Optionally, the length of the first groove structure is 1.5-3 times that of the second groove structure.

Optionally, the proximal end sealing region includes a proximal end sealing support section and at least one proximal end sealing support section, the proximal end sealing support section and the proximal end sealing support section are arranged in an overlapping manner in the axial direction of the main body support portion and are arranged in a staggered manner in the circumferential direction of the main body support portion;

at least one high peak is arranged between any two adjacent low peaks in the at least one high-near-end sealed bracket section.

Optionally, the most proximal end of the one of the high peaks of the high-proximal sealing stent section protrudes axially from the stent graft to form a protruding section, the protruding section is configured to be anchored by being attached to a blood vessel wall after being expanded, and the protruding section is provided with a rear release structure for cooperating with a conveyor to realize rear release of the stent graft.

Optionally, the length of the extending section is 1.5 mm-5.0 mm.

Optionally, the cross-sectional shape of the main body region is circular, the cross-sectional shape of the proximal end of the transition region is circular, and the cross-sectional shape of the distal end of the transition region is elliptical.

Optionally, the covered stent further comprises a branch binding coil configured to bind each stent section of the branch stent parts on the same side, and each stent section of the branch stent parts on the same side is bound by at least two branch binding coils.

In above-mentioned covered stent, utilize the tectorial membrane to connect the annular support section and form the Y shape covered stent of integral type, this kind of covered stent greatly reduced the operation cost, reduced the risk of interior hourglass that the concatenation between traditional art formula support owned, also reduced the operation time simultaneously. In addition, the distal end of the main body stent part of the integrated covered stent is striden over the bifurcation point of the blood vessel after being released, the fixing mode accords with the natural trend of the blood vessel of a human body, and the bifurcation point of the stent can not be displaced. In addition, the annular support sections have smaller pressing and holding size and smaller introduction path, and the annular support sections are flexibly connected through the covering film, so that compared with a woven structure, the flexibility of the support is improved, and the support can be better matched with tortuous blood vessels of a human body. Furthermore, main part support portion still includes the transition district, the external diameter of transition district reduces from near-end to distal end gradually, makes it can with the better of tectorial membrane laminating, also more accords with the natural trend of change of human vascular diameter, further reduces the risk of interior hourglass. Thirdly, main part support portion still includes the near-end sealing area, the near-end sealing area includes at least one and becomes high near-end sealing support section, at least one becomes high near-end sealing support section and can makes the support possess better near-end circularity and bigger radial holding power, can prevent effectively that I type that is not tight by support near-end and vascular laminating causes leaks in, and the structural design that the first section of near-end becomes high simultaneously also can cooperate the back release to make the support release accurate, further promotes the release precision.

In above-mentioned covered stent, utilize the strengthening rib to restrict main part support portion and retract in the axial, under the condition that does not influence the support compliance, the effectual risk that has reduced the support near-end and shift, make the release position more accurate.

In the covered stent, the main stent part further comprises a naked section or an extending section, and a rear release structure is preferably arranged on the naked section or the extending section and can be matched with a conveyor to realize the function of rear release. The backward release can effectively reduce the forward jump and backward jump in the release process of the stent, so that the release position is more accurate. Meanwhile, the positioning effect is better by matching with the arrangement of the striding type positioning and the reinforcing ribs, and the naked section or the extending section does not need barbs, so that the stent can be anchored at the near end without damaging blood vessels.

In above-mentioned tectorial membrane support, usable branch constraint coil is like butterfly type coil, ligatures the branch support portion of homonymy, can effectively avoid the problem that the support that the line node is led to by card owner when releasing can't bounce open, has reduced the operation degree of difficulty, has further shortened operation time.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

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

Fig. 2 is a partial structural schematic diagram of a bare segment according to a first preferred embodiment of the present invention.

Fig. 3 is a schematic structural view of a reinforcing bar according to a first preferred embodiment of the present invention.

Fig. 4 is a schematic structural view of a bracket part of a dental floss binding main body according to the first preferred embodiment of the invention.

Fig. 5 is a schematic structural view of a branch stent portion on the same side as a branch bound coil in the first preferred embodiment of the present invention.

FIG. 6 is a schematic structural view of a stent graft according to a second preferred embodiment of the present invention.

Fig. 7a is a schematic view of a high proximal seal holder segment according to a second preferred embodiment of the invention.

Fig. 7b is a schematic representation of a contoured proximal seal carrier segment according to a second preferred embodiment of the present invention.

FIG. 7c is a schematic view of the axially overlapping and circumferentially staggered arrangement of the contoured proximal seal carrier segments and the tapered proximal seal carrier segments according to the second preferred embodiment of the present invention.

Detailed Description

In order to make the content of the present invention more comprehensible, the present invention is further described with reference to the accompanying drawings. The invention is of course not limited to this particular embodiment, and general alternatives known to those skilled in the art are also covered by the scope of the invention. In the following embodiments, features of the embodiments can be supplemented with each other or combined with each other without conflict.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be understood that the terms "a" or "an," and the like, also do not denote a limitation of quantity, but rather denote the presence of at least one; "plurality" means two or more than two. The word "comprising" or "comprises", and the like, means that the element or item listed as preceding "comprising" or "includes" covers the element or item listed as following "comprising" or "includes" and its equivalents, and does not exclude other elements or items. The present invention is described in detail with reference to the drawings, but these drawings are only for convenience of describing the present invention in detail and should not be construed as limiting the present invention. As used herein, "proximal" refers to the end near the heart; "distal" means the end closer to the operator, i.e., the end further from the heart; "axial" refers to a direction parallel to the axis; "radial" refers to a direction perpendicular to the axis; "circumferential" refers to a direction about an axis. As used herein, "wave bar" is the stent rib, and "wave bar length" refers to the dimension of the stent rib in the direction of extension thereof.

< example one >

As shown in FIG. 1, the present embodiment provides a stent graft 100, which is a one-piece stent structure, i.e., the stent graft 100 is not formed by splicing a plurality of independent stents in vivo, but is fabricated in vitro to form a branched stent structure. The stent graft 100 is suitable for the case where the diseased region of an aneurysm or dissection involves a vascular bifurcation and its branches, including but not limited to the abdominal aorta. In the following description, the affected area involving the abdominal aorta and its branches will be mainly used as an illustration, but the present invention is not limited thereto.

Specifically, the stent graft 100 comprises a stent body including a main stent section 110 and two branch stent sections 120, and the stent graft 100 further comprises a stent graft 130. Both the branch stent sections 120 and the main stent section 110 are fixedly connected to the stent graft 130, thereby integrally connecting the stent graft 100 in a Y-shape. It needs to be understood that the stent body and the covering membrane can be of an integrated structure or a split structure, and the stent body and the covering membrane can be fixedly connected in a split or integrated manner. Herein, the two branch stent portions 120 respectively constitute a branch stent on the same side and a branch stent on the opposite side, and for convenience of explanation, the two branch stent portions 120 are defined as a first branch stent portion 121 and a second branch stent portion 122, the first branch stent portion 121 constituting the branch stent on the same side, and the second branch stent portion 122 constituting the branch stent on the opposite side. The outer diameter of the branched stent section 120 may be small at the proximal end, large at the distal end, or the outer diameter of the branched stent section 120 may be constant.

The main body support part 110 and the branch support parts 120 are both hollow tubular structures, and the inner cavities of the main body support part 110 are communicated with the inner cavities of the two branch support parts 120. The main body support part 110 and the branch support part 120 both comprise a plurality of annular support sections (support sections for short) which are axially arranged at intervals in sequence, the annular support sections are of a wave-shaped structure, and the annular support sections are flexibly connected through the covering film 130, or the support sections are flexibly connected through the covering film 130 except for the reinforcing ribs 105. By "flexibly connected" it is herein understood that the annular stent segments are all fixedly connected only to the cover 130, without a rigid connection between any two adjacent annular stent segments in the axial direction. As shown in fig. 1, there is preferably no rigid connection between the ring stent segments except for the reinforcing ribs 105, that is, the ring stent segments are connected only by the coating 130, and the coating 130 is soft to achieve flexible connection. It is understood that "rigidly connected" means that when the stent graft is displaced or stressed, there is no relative displacement or deformation between the annular stent segments in the stent graft; the flexible connection means that when the covered stent generates displacement or stress, the annular stent sections in the covered stent can generate relative displacement or deformation, and at the moment, the flexibility is good.

The shape of the waveform on the ring-shaped stent segment is not limited by the present application and may be a sawtooth shape or an arc shape or other suitable shape. The metal material for making the stent body is not particularly limited, and can be any medical metal material with good biocompatibility, such as 316 stainless steel, cobalt-chromium alloy or nickel-titanium alloy. The coating 130 is a polymer soft material with good biocompatibility, so that the stent body can form a closed inner cavity in the axial direction, and the coating 130 can be arranged on the inner surface or the outer surface of the stent body.

Compared with the prior art, the covered stent 100 of the invention not only avoids the inner leakage risk caused by splicing a plurality of independent stents in vivo, but also shortens the operation time and greatly reduces the operation cost. Particularly, the far end of the main body support part 110 is positioned on the bifurcation point of the abdominal aorta in a riding mode, the fixing mode accords with the natural trend of the blood vessel of the human body, the bifurcation point of the covered stent 100 can not be displaced, and the risk of displacement of the covered stent can be effectively reduced. In addition, unlike the integrally braided stent structure, the undulating ring stent segments have a smaller crimped size, which means a smaller introduction path and less trauma to the patient. And the wavy annular support sections are not rigidly connected or are not rigidly connected except for reinforcing ribs, so that compared with an integral woven structure, the flexibility of the support is improved, the support can be better matched with tortuous blood vessels of a human body, and the treatment effect is better.

With continued reference to fig. 1, the main body stent section 110 preferably includes a bare section 101, a proximal sealing region 102 and a main body region 103 arranged in sequence from the proximal end to the distal end, all fixedly connected to the covering membrane 130, such as by sewing and/or heat-fusing with the covering membrane 130. Specifically, the annular stent segment comprises a bare segment 101, a proximal sealing stent segment a2, and a main body stent segment a 3; the bare segment 101 may also be understood to comprise one annular stent segment; the proximal sealing area 102 comprises a plurality of proximal sealing support segments a2, and the specific number is not limited; the body region 103 includes a plurality of body support segments a3, and the specific number is not limited. It should be understood that the bare section 101 is not covered with the coating 130, and that the coating 130 is disposed on both the proximal sealing region 102 and the body region 103. It will also be appreciated that the ring stent section further comprises branch stent sections, and each of the branch stent sections comprises a branch stent section.

As shown in fig. 2, the bare segment 101 may be manufactured by a cutting process, the bare segment 101 is a wavy annular stent segment, a distal end of the bare segment 101 is fixedly connected to the coating 130, and a proximal end of the bare segment 101 axially extends out of the coating 130. The bare section 101 is configured to expand and then anchor against the vessel wall, so that the anchoring zone at the proximal end of the main body stent section 110 can be extended, and the bare section 101 has no barb, so that the stent can be anchored at the proximal end without damaging the vessel. Preferably, the bare section 101 is provided with a rear release structure for cooperating with a conveyor to effect rear release of the stent graft. The back release can effectively reduce the front jump and the back jump in the release process of the stent, so that the release position is more accurate and the treatment effect is better. The application does not impose limitations on the manner of post-release. In one embodiment, as shown in FIG. 2, the rear release structure comprises a hole structure 1011, and at least a portion of the peaks of the bare section 101 are provided with the hole structure 1011, and the hole structure 1011 is adapted to mate with a conveyor to achieve rear release of the stent graft.

Preferably, the bare segment 101 is provided with a developing member (not shown) made of a metallic developing material to discriminate the position and form of the stent graft 100 based on the developability of the developing member under X-rays. Further, a groove structure for fixing the developing member is provided on the wave rod 1012 of the bare section 101. The groove structure may include a plurality of first groove structures 1013 and a plurality of second groove structures 1014, the first groove structures 1013 may fix the first developing part, and the second groove structures 1014 may fix the second developing part. First and

second groove structures

1013, 1014 are disposed on the surface of the wave bar 1012 of the bare section 101, and first and

second groove structures

1013, 1014 are disposed on different wave bars 1012 of the bare section 101. Preferably, the surface of the wave bar 1012 of the bare segment 101 is convex, so that a groove structure is formed between the protrusions, thereby securing the strength of the bare segment 101. The first groove structure 1013 has a length greater than that of the second groove structure 1014, and thus, the first developing part has a length greater than that of the second developing part. It should be understood that the length of the groove structure is the dimension along the extension direction of the wave bar 1012. Preferably, the lower edge of the first recess 1013 is flush with the lower edge of the second recess 1014 to ensure that the lower edge of the developer member coincides with the edge of the stent graft 130, which facilitates identification of the position and configuration of the stent graft proximal end. The lower edge of the groove structure refers to the distal edge of the groove structure. Optionally, the length of the second groove structure 1014 can be 1 mm to 3mm, and the length of the first groove structure 1013 can be 2 mm to 6 mm. Further, the length of the first groove structure 1013 is 1.5-3 times of the length of the second groove structure 1014, so as to ensure that the position and the shape of the proximal end of the stent covering membrane can be identified under the X-ray. In this embodiment, a first recess 1013 is provided on the opposite side of the frame to hold the first developing device, and a second recess 1014 is provided in another orientation as required to hold the second developing device for identifying the frame orientation and configuration under X-ray.

Referring to fig. 1, the proximal seal area 102 includes at least one raised proximal seal support section 1021 and at least one raised proximal seal support section 1022. The depth of the valleys in the heightened proximal end sealing stent section 1021 is not the same, and at least one high valley is provided between any two adjacent low valleys in at least one heightened proximal end sealing stent section 1021. The valleys in the contoured proximal seal stent segments 1022 are all of the same depth. "depth of a trough" refers to the vertical distance between adjacent peaks to troughs. At least one high proximal seal holder section 1021 is disposed at the proximal most end of the proximal seal region 102. The number of contoured seal carrier segments 1022 in the proximal seal zone 102 is not limited and can be one or more. Similarly, the number of the high proximal seal holder sections 1021 may be one or more. At least one high proximal seal carrier section 1021 and at least one high proximal seal carrier section 1022 are spaced axially of the main body carrier portion 110 and are aligned circumferentially of the main body carrier portion 110.

In the embodiment shown in fig. 1, the number of the high proximal seal holder sections 1021 is 1, the number of the high proximal seal holder sections 1022 is 3, one high proximal seal holder section 1021 and three high proximal seal holder sections 1022 are sequentially arranged from the proximal end to the distal end at intervals in the axial direction of the main body holder portion 110, and the high proximal seal holder sections 1021 and the high proximal seal holder sections 1022 are arranged in alignment in the circumferential direction of the main body holder portion 110. Here, "alignment" means that, as shown in fig. 1, on a projection plane parallel to the axis of the main body stent portion, a line connecting a projection of a peak of the heightened proximal seal stent section 1021 and a projection of a peak of the equal-height seal stent section 1022 is parallel to the axis of the main body stent portion, and similarly, a line connecting a projection of a valley of the heightened proximal seal stent section 1021 and a projection of a valley of the equal-height seal stent section 1022 is parallel to the axis of the main body stent portion. It should be appreciated that the combination of the stent segments having the two heights, high and equal height, may provide a tighter fit of the proximal end of the stent graft 100 to the vessel, thereby effectively preventing type Ia endoleaks resulting from an inadequate fit of the proximal end of the stent graft 100 to the vessel.

In addition, the maximum length of the wave rod of the proximal sealing bracket section a2 is less than the wave rod length in the main body bracket section a3, for example, the wave rod length of the proximal sealing bracket section a2 is 4 mm-14 mm, and the wave rod length in the main body bracket section a3 is 16 mm-24 mm. Thus, the proximal sealing region 102 is more densely packed in the waveform than the body region 103 and has a better fit with the blood vessel.

With continued reference to fig. 1, body region 103 includes a plurality of axially aligned body stent segments a3, the number of body stent segments a3 being set according to the length of the lesion. The heights of the peaks of body strut segments a3 that make up body region 103 are the same. The body region 103 serves to support the blood flow passageway and allow the stent graft 100 to adhere to the wall. The proximal seal region 102 and the body region 103 are both generally cylindrical in shape, with the same outer diameter.

The main body stent part 110 preferably further comprises a transition region 104, and the bare section 101, the proximal sealing region 102, the main body region 103 and the transition region 104 are arranged in sequence from the proximal end to the distal end, such that the transition region 104 is disposed between the main body region 103 and the branch stent part 120. The outer diameter of the transition region 104 decreases from the proximal end to the distal end, the outer diameter of the proximal end of the transition region 104 being the same as the outer diameter of the body region 103, the body region 103 having the same outer diameter. In addition, the ring-shaped stent segment further comprises a transition stent segment a4, and the transition zone 104 comprises a plurality of transition stent segments a 4. Preferably, the cross-sectional shape of the body region 103 is circular; preferably, the proximal end of the transition region 104 has a circular cross-sectional shape and the distal end of the transition region 104 has an elliptical cross-sectional shape, with the major and minor axes of the ellipse decreasing in order. The number of transition leg a4 making up transition region 104 is not limited and includes, but is not limited to, a transition leg a4, typically a transition leg a 4. Thus, in a preferred embodiment, the proximal cross-section of the main body frame portion 110 is circular and the distal cross-section is elliptical. The transition region 104 is used for making the main body support part 110 and the two branch support parts 120 transition smoothly to conform to the anatomical structure of the blood vessel of the human body, and the fitting effect is good. In addition, the transition area 104 adopts a reducing structure, can be better attached to the reducing section of the covering film 130, and better conforms to the natural variation trend of the diameter of the blood vessel of the human body. Compared with the traditional constant-diameter structure, the arrangement of the transition region 104 can ensure that the covered stent has better lumen retentivity, and effectively avoids the problem that the branch of the stent generates occlusion along with the tortuosity of the blood vessel.

The stent graft 100 preferably further comprises a rib 105 fixedly connected to the stent graft 130, wherein the rib 105 is configured to limit the axial retraction of the main stent section 110. After the reinforcing ribs 105 are used, on the basis of keeping the flexibility of the covered stent 100 as much as possible, the axial shortening of the covered stent 100 can be effectively prevented, and the risk of the proximal displacement of the covered stent 100 is effectively reduced. Preferably, the material of the reinforcing ribs 105 is a biocompatible metal material, including but not limited to nickel titanium, cobalt chromium alloy, or 316 stainless steel.

Referring to fig. 3 in conjunction with fig. 1, the reinforcing rib 105 is an elongated rod-shaped structure and extends along the axial direction of the main body support portion 110, and the proximal end and the distal end of the reinforcing rib 105 are fixedly connected to the covering film 130, such as by sewing and/or heat-melting. Wherein the proximal end of the ribs 105 are disposed on the body region 103 and the distal end is disposed proximal of the transition region 104 to limit axial shortening of the body region 103. Here, it should be understood that the stiffener 105 is actually fixedly attached to the cover 130, but the fixed position of the stiffener 105 to the cover 130 is required to ensure that the distal end of the stiffener 105 is proximal to the transition region 104 and the proximal end of the stiffener 105 is on the body region 103. Preferably, the proximal ends of the ribs 105 are disposed on the first body stent segment a3 at the proximal end of the body region 103, such as at the peaks, valleys or locations between peaks and valleys of the first body stent segment a3 at the proximal end of the body region 103.

The number of ribs 105 is preferably one to ensure compliance of the stent graft. Preferably, the distal ends of the ribs 105 are disposed on the first transition leg segment a4 at the proximal end of the transition region 104, and more preferably, the distal ends of the ribs 105 are disposed on the peaks of the first transition leg segment a4 at the proximal end of the transition region 104. The length of the bead 105 is not particularly limited in the present application, and the length of the bead 105 is specifically determined according to the specification of the main body frame portion 110. For example, in one particular embodiment, the ribs 105 have a length that is 1% to 80% of the axial length of the body region 103.

Further, as shown in fig. 3, fixing holes 1051 may be provided at both ends of the reinforcing ribs 105, and the reinforcing ribs 105 may be connected to the coating film 130 by sewing and/or heat-fusing through the fixing holes 1051 at both ends. The fixing holes 1051 can ensure that the two ends of the reinforcing ribs 105 are firmly fixed with the film 130 and are not easy to slip. The stent graft 100 is positioned in a manner that a stent bifurcation point straddles the abdominal aorta bifurcation point, and the stent graft is matched with the reinforcing ribs 105, so that the stent graft can be effectively prevented from being shortened in the tortuous abdominal aorta, and the positioning accuracy is ensured. It is also understood herein that the annular stent segments are convex proximally as "peaks" and conversely as "valleys".

Referring back to fig. 1, the stent graft 100 preferably further includes a dental floss 140 made of a soft polymer material with good biocompatibility, such as PTFE, PET, or ultra-high molecular polyethylene. The proximal end of the floss 140 is fixedly attached to the cover 130 and is used to ligate each loop stent segment of the main body stent section 110 to reduce the size of the stent and facilitate positional adjustment of the stent within the body.

Referring to fig. 1, the dental floss 140 is knotted to form a plurality of body-binding loops 141 at the knotted portions. The number and position of the main body binding coils 141 correspond to the number and position of the ring-shaped support sections on the main body support part 110 to be bound one by one. In the binding process, as shown in fig. 4, the main body binding coil 141 preferably passes through the binding coil 106 at the corresponding position on the bracket section, so that the diameter binding of the main body bracket part 110 can be minimum, and is about 10% -20% of the nominal diameter of the bracket. Wherein the binding coil 106 plays a role in limiting the binding coil 141 of the main body, and the binding is more reliable and firm. The number and location of the tie coils 106 can be set as desired. The binding structure is reliable and high in strength. The structure of the bound coil 106 is not limited, and the bound coil 106 may be formed by additionally sewing on the stent.

Referring to FIG. 1, the stent graft 100 may further include branch-bound coils 150 made of a soft polymer material with good biocompatibility, such as PTFE, PET, or ultra-high molecular polyethylene. Optionally, the branch-bounding coil 150 is a butterfly-type coil, i.e., a "figure-8" coil. Wherein, each ring-shaped stent section of the first branch stent part 121 is provided with at least 2 branch constrained coils 150, and the at least 2 branch constrained coils 150 of each ring-shaped stent section are preferably fixed on the same circumferential direction of the stent section, and the at least 2 branch constrained coils 150 encircle the stent section from two sides respectively. Due to the adoption of the mountain-turning operation mode, the second branch bracket part 122 at the opposite side does not need to be bound with the branch binding coil 150. The operation mode of the 'mountain turning' is a known technology in the field, namely, the abdominal aorta and the bilateral iliac arteries are in an inverted Y-shaped structure, and the mountain turning is a path for establishing the bilateral iliac arteries from one iliac artery by adopting consumables such as guide wire catheters and the like and is similar to the mountain turning.

Referring to fig. 5, the branch binding coil 150 is wrapped around the first branch supporting portion 121 at two sides, that is, 2 branch binding coils 150 from the same point "hold" the first branch supporting portion 121 from two sides, so as to achieve the binding effect. This simple structure, easy operation, the ligature effect is firm. By adopting the binding structure, the release of the first branch bracket part 121 can be realized by pulling the bound guide wire, and the problem that the bracket cannot be bounced off due to the fact that the wire joint is clamped during the release can be effectively avoided. Likewise, the branch tie coil 150 may be used in conjunction with the tie coil 106 (not shown in fig. 5) on the carrier section of the first branch carrier portion 121, the tie coil 106 serving to limit the branch tie coil 150, making the strapping more reliable.

The size and distribution characteristics of human blood vessels vary greatly from individual to individual, and for this reason, the size of the stent graft 100 may be selected according to the size of the blood vessel of the patient. In an exemplary embodiment, as shown in fig. 1, the length L1 of the main body bracket portion 110 is 30mm to 130mm, the diameter D1 of the main body bracket portion 110 is 16mm to 34mm, the length L2 of the first branch bracket portion 121 is 20mm to 80mm, the length L3 of the second branch bracket portion 122 is 20mm to 80mm, the diameter D2 of the first branch bracket portion 121 is 8mm to 24mm, and the diameter D3 of the second branch bracket portion 122 is 8mm to 24 mm. Different from the traditional covered stent, when the diameter of the blood vessel at the iliac artery lesion part of the patient is large, the size of the branch stent part 120 can be adjusted according to the special condition of the patient, and finally the integrated covered stent 100 is manufactured. That is, the sum of the diameters of the two leg portions 120 may be greater than the diameter of the main body leg portion 110, or may be smaller than or equal to the diameter of the main body leg portion 110.

< example two >

Referring to FIGS. 6, 7a, 7b, and 7c, in another embodiment of the present invention, a stent graft 100 ' is provided, in which a bare section of the stent graft 100 ' is eliminated, and a proximal sealing region 102 ' is directly disposed at the proximal end of a main body stent portion 110, that is, the main body stent portion 110 of the stent graft 100 ' of this embodiment includes a proximal sealing region 102 ', a main body region 103, and a transition region 104, which are sequentially arranged from the proximal end to the distal end. A further difference is that the relative positions of the high proximal seal carrier segments 121 and the high proximal seal carrier segments 122 in the proximal seal zone 102' are adjusted.

Specifically, in this embodiment, the proximal seal region 102' includes one raised proximal seal carrier section 1021 and at least one raised proximal seal carrier section 1022. A proximal seal support section 1021 of varying height and a proximal seal support section 1022 of varying height are arranged in an overlapping manner in the axial direction of the main body support portion 110 and are arranged in a staggered manner in the circumferential direction of the main body support portion 110, thereby forming a support section of varying height and varying height in an overlapping manner at the proximal end of the proximal seal region 102. At least one high peak is arranged between any two adjacent short peaks in the annular support section formed after overlapping. Wherein the lower vertices of the tall peaks are aligned with and on the same circumference as the lower vertices of the short peaks. Thus, the lower apices of the annular stent segments formed after the overlap are aligned and the upper apices exhibit a height variation. It should also be understood that "axially overlapping" means that one raised proximal seal carrier section 1021 and at least one raised proximal seal carrier section 1022 are in the same circumferential direction; by "circumferentially staggered" is meant that one raised proximal seal carrier section 1021 and at least one raised proximal seal carrier section 1022 are staggered in the same circumferential direction between the peaks without overlapping, as shown in fig. 7 c. In this embodiment, at least one high proximal seal holder section 1021 is disposed at the proximal end of the proximal seal region 102', and at least one high peak is disposed between any two adjacent low peaks in the at least one high proximal seal holder section 1021.

At this moment, the alternating structure design of the proximal end of the main body support part 110, such as the height and the height, can make the proximal end of the support tightly fit with the blood vessel, can effectively prevent the leakage in the Ia type caused by the loose fit of the proximal end of the support and the blood vessel, and can make the support have better roundness of the proximal end and larger radial supporting force, thereby effectively preventing the leakage in the I type caused by the loose fit of the proximal end of the support and the blood vessel, and simultaneously the structure design of the proximal end section height can also be matched with the back release to make the release of the support accurate.

As shown in fig. 6, the portion of the proximal end variable-height sealed stent section 1021 extending out of the coating 130 in the axial direction forms an extending section, at this time, the length of the extending section is preferably 1.5mm to 5mm, the number of the high peaks in the proximal end variable-height sealed stent section 1021 is about 3 to 6, and a hole structure can be arranged on the high peaks to cooperate with a conveyor to realize a back release function, so that the forward jump and the backward jump in the stent release process can be effectively reduced, and the release position is more accurate. Moreover, the structure is convenient to be matched with a cylindrical bracket (CUFF) for use. The length of the treatment area can be increased by using the CUFF. When used in combination with various open-cell CUFFs, the open-cell CUFFs can reconstruct the blood flow path of the branch vessels in the proximal visceral area. The use mode and the size are very flexible.

The remaining structure of the stent graft 100' shown in this embodiment is substantially the same as that of the stent graft 100 of the first embodiment, and for the same parts, detailed description is omitted, and specific reference may be made to the first embodiment.

It should be understood that after the stent graft of the present invention is released, the bifurcation point of the stent graft coincides with the human iliac bifurcation point, i.e. the distal end of the stent body stent part straddles the iliac bifurcation point. The fixing mode accords with the natural trend of human blood vessels, the bifurcation point of the stent can not shift, and particularly, when the fixing mode is matched with the reinforcing ribs, the far ends of the reinforcing ribs are arranged at the near ends of the transition areas, so that the risks of stent shortening and near-end shifting are effectively reduced. Meanwhile, the barb-free design of the bare section or the extended section avoids the damage of the barb to the blood vessel on one hand, and prolongs the anchoring area of the near end of the stent on the other hand, so that the application range of the stent can be widened, and the near end of the stent can be well anchored with the blood vessel. In addition, the special structural design of near-end sealing area and transition zone can make main part support portion and blood vessel closely laminate, has greatly reduced the risk of Ia type internal leakage. The distal end of the abdominal aorta of the human body is bifurcated into the iliac arteries on two sides, so the covered stent is particularly suitable for the abdominal aorta, and meanwhile, the risk of internal leakage and the risk of long-term displacement are low, and the defects of the existing covered stent are effectively overcome.

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 present invention.

Claims

1. A covered stent is characterized in that the covered stent is of an integrated stent structure and comprises a stent body, reinforcing ribs and a covered membrane; the covering film is arranged on the surface of the stent body; the bracket body comprises a main bracket part and a branch bracket part; the two branch support parts and the main body support part are fixedly connected with the film and integrally connected to form a Y-shaped structure; the length of the branch support part is 20 mm-80 mm, and the outer diameter of the branch support part is small at the near end and large at the far end; and the bifurcation point of the stent graft is used for adapting to the vessel bifurcation point so that the stent graft can straddle the vessel bifurcation point;

the bracket body comprises a plurality of annular bracket sections which are sequentially arranged at intervals in the axial direction;

the bracket section comprises a near-end sealing bracket section, a transition bracket section, a main bracket section and a branch bracket section; the proximal sealing zone comprises the proximal sealing stent segment, the transition zone comprises the transition stent segment, and the body zone comprises the body stent segment;

the maximum length of the wave bar of the proximal seal support section is less than the length of the wave bar of the main body support section;

the reinforcing ribs are arranged on the opposite side of the covered stent and fixedly connected with the covering membrane, and the reinforcing ribs extend along the axial direction of the main stent part;

the far end of the reinforcing rib is arranged on the wave crest of the first transition bracket section at the near end of the transition region, the near end of the reinforcing rib is arranged on the first main bracket section at the near end of the main body region, and the reinforcing rib can limit the main bracket part from retracting in the axial direction;

the proximal end sealing area comprises a variable-height proximal end sealing support section and at least one constant-height proximal end sealing support section, the variable-height proximal end sealing support section and the constant-height proximal end sealing support section at the most proximal end are arranged in an overlapped mode in the axial direction of the main body support part and are arranged in a staggered mode in the circumferential direction of the main body support part; said at least one heightened proximal seal holder section is disposed at a proximal-most end of said proximal seal zone; at least one high peak is arranged between any two adjacent low peaks in the at least one high-near-end sealed bracket section; most proximal end become the near-end axial of the high crest of near-end sealed support section of height stretch out in the tectorial membrane forms the section of stretching out, stretch out the section and be configured as after the expansion and laminate with the vascular wall and anchor, stretch out and be provided with back release structure on the section for release after with the conveyer cooperation in order to realize the tectorial membrane support.

2. The stent graft of claim 1, wherein the length of the ribs is from 1% to 80% of the axial length of the body region.

3. The stent graft of claim 1, wherein the length of the extension is from 1.5mm to 5.0 mm.

4. The stent graft of claim 1, wherein the cross-sectional shape of the body region is circular, the cross-sectional shape of the proximal end of the transition region is circular, and the cross-sectional shape of the distal end of the transition region is elliptical.

5. The stent-graft of claim 1, further comprising a branch tie coil configured for tying each stent segment of the branch stent portions on the same side, each stent segment of the branch stent portions on the same side being tied by at least two of the branch tie coils.