CN114569301A

CN114569301A - Covered stent

Info

Publication number: CN114569301A
Application number: CN202011391335.2A
Authority: CN
Inventors: 肖本好; 明廷伯
Original assignee: Lifetech Scientific Shenzhen Co Ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2020-12-02
Filing date: 2020-12-02
Publication date: 2022-06-03

Abstract

The invention provides a covered stent, which comprises a main body covered membrane, wherein a window is formed on the surface of the main body covered membrane, the covered stent also comprises an internal connection covered membrane, the edge of the internal connection covered membrane is connected with the main body covered membrane, the window comprises a first edge and a second edge which extend along the length extension direction of the covered stent, and the internal connection covered membrane and the main body covered membrane are spliced and connected after being formed separately. The internal connection tectorial membrane of the tectorial membrane stent is spliced and connected with the main tectorial membrane after being independently formed, thereby greatly reducing the manufacturing difficulty of the tectorial membrane stent.

Description

Covered stent

Technical Field

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

Background

Aortic aneurysms and aortic dissections are diseases that present serious risks to human life safety, and if not treated actively, the body of the aneurysm and dissections will continue to enlarge and eventually break, causing serious complications and death. With the increasing number of patients with hypertension, hyperlipidemia and hyperglycemia, the incidence rate of aortic aneurysm and aortic dissection is also remarkably increased at present.

The traditional open surgery for treating aortic aneurysm and aortic dissection has the characteristics of large trauma, high mortality, long operation time, high incidence rate of postoperative complications and high operation difficulty, while the intracavity therapy has the characteristics of small trauma, few postoperative complications, short operation time, low operation difficulty and the like, and gradually becomes the main mode for treating aortic aneurysm and aortic dissection at present. Through implanting the covered stent in the aorta, the vascular lesion is isolated outside the covered stent, and the blood flow is restricted to flow through the covered stent, so that the purpose of protecting the blood vessel is achieved. Because the stent graft needs to have an anchoring area with a certain length to ensure the fixation of the stent graft and prevent blood from flowing into the blood vessel through the near-far end of the stent graft, when aortic aneurysm or dissection affects the branch arterial blood vessel, the branch artery can be blocked to different degrees when the stent graft is implanted for treatment, and even the treatment can not be carried out by the intracavity technology.

For the intracavity treatment of aortic aneurysm or dissection affected branch artery, in order to realize blood circulation of branch artery, windowing stent technology and chimney stent technology are mostly adopted. The windowing stent technology is characterized in that a side hole is manufactured on a stent in an in-vitro or in-situ windowing mode, the position of the side hole corresponds to the opening position of a branch artery, the stent is implanted in the operation, the opening position is aligned with the branch artery, and then a bridging stent is implanted into the branch artery to be matched with the stent graft; the chimney stent technology is that after the covered stent is implanted, a bridging stent is implanted through a branch artery to be matched with the covered stent. Generally, the windowing bracket technology has high positioning difficulty, needs customization and long time, and cannot be used for emergency treatment; the chimney stent technology is easy to leak inwards, is limited by the anatomical form of blood vessels, and has high difficulty in reconstructing multi-branch arteries. Meanwhile, no matter the windowing stent or the chimney stent technology is adopted, before the branch artery is not reconstructed, the branch artery is always in an ischemic state, and the probability of postoperative complications is high.

Disclosure of Invention

In order to solve the problems, the invention provides a covered stent which comprises a main body covered membrane, wherein a window is formed on the surface of the main body covered membrane, the covered stent also comprises an internal connection covered membrane, the edge of the internal connection covered membrane is connected with the main body covered membrane, the window comprises a first edge and a second edge which extend along the length extension direction of the covered stent, and the internal connection covered membrane and the main body covered membrane are connected in a splicing mode after being formed separately.

In an embodiment, the inscribed coating film comprises a bottom located between the first edge and the second edge, and a support unit is arranged on the inscribed coating film, so that the bottom is at least partially convex outwards or partially concave inwards or parallel to a plane where the first edge and the second edge are located relative to the plane.

In one embodiment, the supporting unit comprises a suture, and the suture passes through the upper surface and the lower surface of the internal connection coating after passing around the first edge and the edge of the internal connection coating to reach the second edge, and then passes around the second edge and the other edge of the internal connection coating to connect the internal connection coating and the main body stent.

In one embodiment, the extension ratio of the internal connection coating film is greater than 0.01 and less than 0.1.

In one embodiment, the support unit comprises a corrugated support structure attached to the surface of the inner graft film.

In one embodiment, the stent graft includes a window support member, the window support member is disposed outside the inner graft film and protrudes outward from the surface of the inner graft film, and the wave-shaped support structure and the window support member are integrally formed.

In one embodiment, the inscribed coating film comprises a bottom, a near-end folded part and a far-end folded part, the near-end folded part and the far-end folded part are respectively arranged at two ends of the bottom, and at least one of the near-end folded part and the far-end folded part is arranged on the inner surface of the main body coating film; the supporting unit is arranged at the bottom, and the folding part is closer to the central axis of the covered stent than the bottom.

In one embodiment, the surface of the window support is formed with a sunken section, and the cross section of the stent graft where the sunken section is located has an area smaller than that of the cross section of the other part of the stent graft far away from the sunken section.

In one embodiment, the stent graft further comprises a main body support, the main body support is connected with the main body cover, the window support is a part of the main body support, and on the same cross section, the circumferential occupation ratio of the window support is smaller than that of the main body support.

In one embodiment, the window support comprises a mesh structure having mesh holes whose size is variable by an external force.

In one embodiment, the proximal and/or distal ends of the window support extend beyond the edge of the window in the lengthwise direction of the stent graft.

The covered stent provided by the invention can effectively isolate the aortic dissection and aortic aneurysm which are affected to the aortic branch artery, effectively rebuilds the blood circulation of the branch artery, avoids the long-time ischemia of the branch artery, has small operation difficulty, does not need to be customized, and can be used for emergency treatment.

Drawings

FIG. 1 is a schematic view of the overall structure of a stent graft according to an embodiment of the present invention, which includes a main stent graft, a branch stent graft and an inscribed stent graft;

FIG. 2 is a schematic structural view of a main stent in the stent graft shown in FIG. 1;

FIG. 3 is a schematic view of the stent graft shown in FIG. 1 after the interconnection of the inner graft and the branch stent;

FIG. 4 is a schematic view of an internal stent graft configuration of the stent graft shown in FIG. 1;

FIG. 5 is a side view of the inner graft shown in FIG. 4;

FIG. 6 illustrates a top view of the stent graft shown in FIG. 1 with portions of the structure omitted;

FIG. 7 is a schematic view of a portion of a stent graft according to another embodiment of the present invention;

FIG. 8 is a schematic view of a portion of a stent graft according to yet another embodiment of the present invention;

FIG. 9 is a schematic view of the stent graft of the present invention after implantation in an aneurysm vessel;

FIG. 10 is a schematic view of a stent graft according to an embodiment of the present invention, including a window support;

FIG. 11 is a schematic view of the window support of FIG. 10;

FIG. 12 is a schematic view of a portion of the window support of FIG. 11;

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

FIG. 14 is a simplified cross-sectional profile view of the stent graft shown in FIG. 13;

FIG. 15 is a schematic view of a window support of a stent graft according to an embodiment of the present invention;

FIG. 16 is an enlarged view of a portion of the window support of FIG. 15;

FIG. 17 is a schematic view of a window support of a stent graft according to another embodiment of the present invention;

FIG. 18 is a schematic structural view of a branch stent of a stent graft according to an embodiment of the present invention;

FIG. 19 is a side view of a stent graft incorporating the branched stent of FIG. 18;

FIG. 20 is a schematic view of a branched stent structure of a stent graft according to another embodiment of the present invention;

FIG. 21 is a side view of a stent graft incorporating the branched stent shown in FIG. 20;

FIG. 22 is a schematic structural view of a branched stent of a stent graft according to yet another embodiment of the present invention;

FIG. 23 is a side view of a stent graft incorporating the branched stent of FIG. 22;

FIG. 24 is a schematic view of a portion of a stent graft according to an embodiment of the present invention;

FIG. 25 is a partial schematic structural view of the stent graft shown in FIG. 24;

FIG. 26 is a schematic view showing the state before and after the extension of the inner coating film;

FIG. 27 is a schematic view of a portion of a stent graft according to an embodiment of the invention, including a reinforcement member;

fig. 28 shows several variations of the reinforcement member shown in fig. 27.

Detailed Description

For better understanding of the concept of the present invention, the following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings, which are included to illustrate and not to limit the present invention.

For the stent graft of the present invention, it is defined that the end into which blood flows is the "proximal end" and the end from which blood flows is the "distal end", i.e., in use, blood flows from the proximal end to the distal end of the stent graft.

Example one

As shown in fig. 1, the stent graft 10 of the present embodiment has an overall hollow tubular structure with openings at both ends, and includes a main stent 11, a branch stent 12, an inscribed stent graft 14, and a window support 15. Wherein, the surface of the main body bracket 11 is provided with a window 13, and the edge of the internal connection tectorial membrane 14 is connected with the main body bracket 1; the window support 15 is provided outside the inner cover film 14 and protrudes outward from the surface of the inner cover film 14. The internal connection tectorial membrane 14 is provided with a through hole which is communicated with the inner cavity of the tectorial membrane stent 10; as shown in FIG. 3, the branch stent 12 has a hollow cylindrical structure, is disposed inside the stent graft 10 and communicates with the through-hole of the inner graft 14, so that blood can flow into the branch vessel through the branch stent 12. In this embodiment, the stent graft 10 includes 3 branch stents 12, wherein two branch stents 12 are disposed near the proximal end of the window 13 and one branch stent 12 is disposed near the distal end of the window 13.

As shown in fig. 2, the main body stent 11 includes a main body support 111 and a main body cover 112, and the main body support 111 is disposed on the surface of the main body cover 112. It should be understood that the body support 111 may be disposed on the inner surface of the body cover 112, or may be disposed on the outer surface of the body cover, or that a portion of the body support may be disposed on the outer surface of the body cover and another portion of the body support may be disposed on the inner surface of the body cover.

The window 13 is opened on the body cover film 112 and is opened in the middle of the body cover film 112, that is, there are also a body support 111 and a body cover film 112 between the end of the window 13 and the end of the body holder 11. In the present embodiment, the edge of the window 13 formed on the main body cover film 112 is rectangular, that is, when the main body cover film 112 is spread along a bus line that does not pass through the window, the window 13 is rectangular; the window 13 has a first edge 131, a second edge 132, a third edge 133 and a fourth edge 134, the four edges enclosing the resulting window 13. Wherein the first edge 131 and the second edge 132 are opposed and aligned with the direction of longitudinal extension of the stent graft 10, and the third edge 133 and the fourth edge 134 are opposed and are closer to the ends of the stent graft 10 than the first edge 131 and the second edge 132. It will be appreciated that in other embodiments, the window can have other shapes, as long as the first edge and the second edge extend along the length of the stent graft, for example, at an angle to the length of the stent graft (e.g., the window has a trapezoidal shape), or the first edge and the second edge have an arcuate shape (e.g., the window has an elliptical shape), and the invention is not limited to the particular shape of the window. It is also understood that the window may be near the proximal end of the stent graft or near the distal end of the stent graft.

As shown in FIGS. 1 and 4, the stent graft 10 of the present embodiment includes an inner graft 14, and the edge of the inner graft 14 is connected to the edge of the window. Specifically, the inner cover film 14 includes a bottom 141 and a folded portion 142, and the folded portion 142 is provided at an end of the bottom 141. The folded portion 142 is disposed on the inner surface of the main body frame, and the folded portion 142 is recessed toward the inner cavity of the main body frame 11 to form a receiving cavity 144. The receiving cavity 144 has an upper edge 143, and the upper edge 143 is connected to the third edge 133 of the window 13. Specifically, the folding part 142 includes an upper folding unit 1421 and a lower unit 1422 connected to the bottom 141, and the side edges of the upper folding unit 1421 and the lower unit 1422 are connected and jointly enclose to form the receiving cavity 144.

It will be appreciated that in other embodiments, the edge of the inner graft membrane may be attached to the inner surface of the main body graft membrane.

As shown in FIG. 5, the internal stent graft 14 is further provided with a through hole 147 communicating with the lumen of the main stent graft, wherein the through hole 147 faces the opening of the stent graft 10 and also faces the opening of the receiving cavity 144. Because the folding part is provided with the accommodating cavity, when the implantation path of the bridging bracket is established, the guide wire or the catheter can extend into the branch bracket along the accommodating cavity, thereby quickly establishing the implantation path of the bridging bracket and shortening the operation time.

Referring to fig. 4 again, the internal connection covering film 14 of the present embodiment has two folded portions 142 (including a proximal folded portion and a distal folded portion respectively disposed at the proximal end and the distal end of the internal connection covering film), and the two folded portions 142 are both provided with through holes 147, wherein the proximal folded portion 142 is provided with two through holes, and the distal folded portion 142 is provided with one through hole. In the present embodiment, the folded-over portion is formed by folding back the end of the inner coating film 14, specifically, by folding back the end of the inner coating film 14 away from the bottom 141 and toward the inner surface of the main body frame 11. It is understood that the two fold-over structures of the present embodiment may be identical or slightly different.

When the stent graft of the present invention is used for bending a blood vessel, in order to reduce the tension applied to the inner graft due to adaptation to the bending of the blood vessel, the angle between the extension direction of the braided wire of the inner graft and the length extension direction of the stent graft may be set to be greater than 0 degree.

It is understood that in other embodiments, the inner coating film may be provided with the folded portion only at the proximal end, and the number of the through holes may be 1 to 3. In the present invention, the positions and the number of the branch stents 12 correspond to the positions and the number of the through holes, that is, when a plurality of through holes are provided at one end of the internal graft, the same number of branch stents 12 are provided at the same end of the internal graft, and the through holes may be arranged in a staggered manner or on the same cross section perpendicular to the central axis of the graft.

It will also be appreciated that in other embodiments, the flap having the receiving cavity may be separately formed as a pocket having the receiving cavity and then connected to the bottom and the window edge, respectively.

It will also be appreciated that in other embodiments, only one flap may define the receiving cavity and the other flap may merely be a ramp extending from the base to the inner surface of the body support, although a through hole may be provided in this ramp. It will also be appreciated that the through-holes may also be provided on the bottom.

In this embodiment, the inner graft film 14 is formed separately from the main body film 112 and then attached thereto by stitching, although in other embodiments, the two may be attached by adhesive or other means. Because the branch support is further arranged on the internal connection coating film, the internal connection coating film and the main body coating film are spliced after being formed independently, and the manufacturing difficulty can be greatly reduced. It will be appreciated that in other embodiments, the inner cover film may be integrally formed with the main body cover film when no folds and branch stents are provided on the inner cover film.

Returning again to fig. 4 and 5, the inner cavity (i.e., the size of the receiving cavity) of the folded part 142 of the present embodiment gradually decreases from the opening position toward the through hole 147 (i.e., gradually decreases toward the opening of the stent graft end), so that the guide wire can be more quickly selected into the branch stent along the receiving cavity of the stent graft 3 when the bridge stent is implanted.

Returning to fig. 1 and 2 again, the window 13 of the stent graft 10 is further provided with a window support 15, and the cross section of the window support 15 has an arch structure, is arranged above the inner graft 14, and protrudes outwards from the surface of the inner graft 14. In the present embodiment, the window supporting member 15 and a part of the main body supporting member 111 are integrally formed, that is, the window supporting member 15 is a part of the main body supporting member 111, and during the preparation, a window is firstly opened on the main body coating film, and then the main body supporting member 111 is connected with the main body coating film, wherein the main body supporting member with the exposed window portion constitutes the window supporting member. Preferably, the circumferential ratio of the window support member of the present embodiment is smaller than that of the main body support member, that is, on the same cross section, the ratio of the window support member to the circumference of the cross section is smaller than that of the main body support member to the circumference of the cross section, so that it can be ensured that the size of the inner cavity of the main body stent at the position where the inscribed coating film is provided is not too small, and thus the hemodynamics in the aorta is not affected. It will be appreciated that in other implementations, the circumferential aspect ratio of the window support may also be equal to or greater than the circumferential aspect ratio of the body support.

As shown in fig. 6, the window support 15 of the present embodiment includes a plurality of support sections 151, the plurality of support sections 151 are axially spaced, and the support sections 151 are circumferentially connected to the main body bracket 11 (fig. 6 only shows a partial structure of the main body bracket). In this embodiment, the support segment 151 includes a plurality of Z-shaped structures connected end to end, and the Z-shaped structures have a wave crest and a wave trough, and the axial distance between the wave crest and the wave trough is the wave height of the Z-shaped structures. In order to better fit the bridge stent into the branch stent and minimize interference and obstruction of the bridge stent by the window support, in the window support 15 of the present embodiment, the distance between the peak of the support segment 151 close to the third edge 133 of the window and the third edge 133 is preferably 10-20 mm, so that it is not necessary to choose the peak between the valley of the support segment 151 and the third edge 133 when implanting the bridge stent. Similarly, the distance between the wave trough of the supporting section close to the fourth edge of the window and the fourth edge can also be selected to be 10-20 mm. It will be appreciated that in other embodiments, the placement of the bridging stent between the trough and the third edge of the strut section may be precisely selected, and the distance between the peak and the third edge of the strut section near the third edge of the window may not be limited, and in such cases, it may be preferable that the height of the strut section is 6-12 mm. Wherein reference numeral 01 in fig. 6 shows a partially optional placement position of the bridging bracket. In other embodiments, the implantation position of the bridging stent may also be optimized by changing the wave height of the strut segments, for example, the strut segments near the third edge and/or the fourth edge may be set to have a higher wave height than the other strut segments, or the strut segments with a higher wave height may be set at the position where the bridging stent needs to be placed, without being limited to the strut segments near the third edge and the fourth edge.

It will be appreciated that in other embodiments, two adjacent strut sections adjacent to the through-hole of the inner graft membrane are of an inverted configuration, that is, the peaks of one strut section are opposite the troughs of the other strut section, so that when the position of implantation of the bridging stent is selected, the position between the opposite peaks and troughs can be selected.

As shown in fig. 6, in the present embodiment, the third edge 133 of the window 13 is located between the window support 15 and the body support 111, and the upper edge 143 of the folded portion 142 is connected to the third edge 133, in this case, in order to maintain the folded portion 142 in a good opening form, a reinforcement may be provided on the opening of the folded portion 142, and for example, stitches may be added or subtracted on the upper edge 143 to appropriately reduce the deformability of the upper edge 143. It will be appreciated that in other embodiments, the third edge may be partially coincident with the body support or the window support (i.e., the support section partially overlaps the third edge of the window), and in this case, the opening edge (i.e., the upper edge) of the receiving cavity is also partially coincident with the body support or the window support, that is, in a plane parallel to the bottom of the inscribed coating film, the projections of the third edge and the upper edge of the receiving cavity are coincident with the body support or the window support. At this time, the body support member or the window support member can also function as an opening of the housing chamber for supporting the folded portion, which is equivalent to a reinforcement member. It will also be appreciated that in other embodiments, the reinforcement may be provided separately, as will be described in more detail below.

In other embodiments, as shown in FIG. 7, the stent graft may further include a connector 252, the connector 252 being disposed over the window 23, and the plurality of support segments 251 being connected by the connector 252. In addition, the proximal and/or distal ends of the connecting member 252 may also extend onto the body support 211 to connect with the body support 211. The connecting members 252 are preferably connected to the peaks of adjacent support segments 251. More preferably, the connector is positioned just on the steep curve side of the stent graft when the stent graft is implanted in a curved vessel. In this embodiment, the connecting member 251 is a connecting rod, and the length extending direction of the connecting member 251 is the same as the extending direction of the covered stent. It will be appreciated that in other embodiments, the connector may only connect the support sections of the window support without extending to the body bracket. The material of the connecting piece can be selected from medical metal materials, such as super-elastic nickel-titanium wires, medical stainless steel wires and the like. The connecting piece and the support section can be connected by crimping or welding and the like. It will be appreciated that in other embodiments, the connectors may also be angled with respect to the length of the stent graft. Through setting up the connecting piece, can reduce the mutual interference between the support section, avoid the support to shorten simultaneously, improve window support piece's whole support performance, also can make when the covered stent is used for crooked blood vessel, because the restriction of connecting piece, the crest of support section 251 can not the perk, can adapt to vascular crooked form better.

In other embodiments, as shown in fig. 8, the connecting member 352 may include a plurality of segments 353, two adjacent segments 353 are arranged at an offset position, and two adjacent support segments are connected by one segment 353. At this time, the segments 353 may be attached at any position between two adjacent support segments, and preferably the extension direction of the segments 353 coincides with the extension direction of the stent graft. Of course, the segments may also be arranged without offset, i.e. corresponding to the connection shown in fig. 7 comprising a plurality of segments. When the connecting piece comprises a plurality of segments which are arranged in a staggered mode, the selected site of the bridging stent is more flexible, and the implanted bridging stent and the branch blood vessel have better matching forms.

As shown in FIG. 9, the stent graft 10 of the present invention may be used for the intraluminal treatment of aortic arch aneurysms as well as the treatment of thoraco-abdominal aortic aneurysms. Because the window support is arranged on the window of the stent graft 10, good radial support force can be provided, especially when the stent graft 10 is used for treating a dissected aneurysm, even if the true lumen is small, the stent graft 10 can provide good radial support force before the stent graft 100 is implanted, and especially when the stent graft 10 is used for bending a blood vessel, after the stent graft 10 adapts to the shape of the blood vessel, due to the existence of the window support, the space between the window and the blood vessel wall can not be excessively extruded, so that enough selected space is reserved for the implantation of the bridge stent 100. In addition, the blood flow supply of the branch blood vessel can be maintained before the bridging stent 100 is implanted, the probability of ischemic complications after the operation is greatly reduced, and simultaneously, the operation time is abundant for doctors.

Example two

As shown in FIG. 10, the stent graft 40 of the present embodiment has substantially the same structure as the stent graft 10 of the first embodiment, except for the window support 45. The window supporting member 45 of the present embodiment is formed separately, and the body supporting member 411 opposite to the window supporting member 45 has an open structure, that is, the supporting member of the other portion of the body frame has a closed ring structure, and the body supporting member 411 opposite to the window supporting member 45 has not a complete ring shape.

As shown in fig. 11 and 12, the window supporter 45 of the present embodiment includes a plurality of supporting sections 451, the plurality of supporting sections 451 are connected to the edge of the body frame window 43, and the plurality of supporting sections 451 are connected by hooking to each other, thereby forming a net structure having a mesh 456. The mesh structure includes a portion formed by knitting of knitting wires, the intersections of which form the vertices of the mesh 456. The apexes of the mesh openings 456 are formed by the woven filaments being pressed or hooked together so that the crossing points of the woven filaments are movable. Therefore, the size of the mesh may be changed by an external force. For example, when the bridging stent is implanted, the outer diameter of the sheath of the conveyor is larger than the mesh openings, and at this time, the size of the mesh openings can be increased under the extrusion of the sheath, or when the outer diameter of the implanted bridging stent is larger than the size of the mesh openings, the braided wires can not extrude the bridging stent, and can fix the position of the bridging stent to a certain extent, thereby increasing the stability of the bridging stent against the blood flow impact after the implantation.

As shown in FIG. 12, two adjacent support sections 451 are connected in a hanging manner, that is, the wave crests of one support section 451 are hooked with the wave troughs of the other adjacent support section 451. The height h of the single supporting section 451 ranges from 6 mm to 20 mm, and the distance L0 between adjacent peaks or between adjacent valleys of the single supporting section 451 ranges from 10 mm to 25 mm, so that the space is not too small when the bridging stent is implanted. There is certain distance h0 between the crest and the trough of two support sections 451 of hook each other, and this distance is between 0 ~ 5 millimeter, like this, can be so that leave certain tensile distance between the adjacent support section, when the covered stent of this embodiment is implanted to crooked blood vessel, window support piece is towards big curved side to, can also have certain tensile surplus between a plurality of support sections 451, covered stent can adapt to crooked blood vessel better.

Preferably, the same support section 451 comprises two support rings arranged in an overlapping manner in the circumferential direction, so that the mesh of the mesh structure is in a diamond shape, and the adherence and the support of the window support are also enhanced to some extent. It is understood that in other embodiments, the same support segment may include a plurality of support rings arranged in an overlapping manner, and the mesh size is smaller when the number of support rings is larger, so that it is preferable that the number of support rings arranged in an overlapping manner on the same support segment is 2-4.

In this embodiment, the window support 45 is partially overlapped with the main body coating of the main body stent, so that the window support can be sewn conveniently, and meanwhile, the window support close to the opening part of the accommodating cavity of the folded part can also play a role of a reinforcing part, so that the opening shape can be ensured to be good. It will be appreciated that in other embodiments, the window support may not have any overlapping portion with the body covering membrane, and in such cases, the window support may be sewn directly by stitching.

It will also be appreciated that in other embodiments, the sum of the perimeter of the cross-section of the window support and the perimeter of the cross-section of the opposing main stent is greater than the perimeter of the stent graft at that cross-section, i.e., there is a partial overlap of the window support and the main stent support in the circumferential direction, so that the adherence of the first and second edges of the window to the main stent and the support of that portion are suitably enhanced and the stent graft is less likely to collapse.

In this embodiment, the window support 45 naturally transitions with the surface of the main stent, that is, substantially the same for either cross-section of the stent graft 40.

In other embodiments, as shown in fig. 13 and 14, the surface of the window support 55 forms a sunken section 554, the sunken section 554 being closer to the inner graft than other portions of the window support 55, such that the sunken section 554 is in a cross-sectional area of the stent graft that is smaller than the cross-sectional area of other portions of the stent graft that are distal from the sunken section 554. Transition sections 555 and connecting sections 556 are further arranged at two ends connected with the sunken section 554, wherein the transition sections 555 are inclined planes and are arranged between the sunken section 554 and the connecting sections 556, and the connecting sections 556 are connected with the main body support and are in the same curved plane with the outer surface of the main body support. It is understood that in other embodiments, the connecting section may not be included, and in this case, the other end of the transition section is directly connected to the main body bracket; alternatively, in other embodiments, the transition section is a vertical plane. When the window support piece of the tectorial membrane support has a sinking section, after the tectorial membrane support piece is implanted into a bent blood vessel, the deformation amount of the window support piece is small, and the extrusion of the blood vessel wall at the large bending side of the blood vessel is relatively small, so that the reaction force of the window support piece to the blood vessel wall is also reduced, the long-term effect after the reconstruction of a diseased blood vessel is better, and the secondary laceration and the like are not easy to occur.

In other embodiments, the window support member and the opposite main body support member may be integrally woven, and at this time, the weaving density of the window support member may be controlled to be greater than that of the opposite main body support member, so that the compliance of the whole covered stent (especially, the position where the window is provided) may be improved, and the adherence of the positions where the first edge and the second edge of the window are located may also be improved. Of course, in other embodiments, the window support may be woven separately from the opposing body support, with the window support having a greater weave density than the opposing body support.

EXAMPLE III

The stent graft structure of this embodiment is substantially the same as the stent graft structure of the second embodiment, except for the window support 65. As shown in fig. 15 and 16, the window supporter 65 of the present embodiment is formed by interweaving the knitting yarns 657, and the meshes 656 have a diamond structure. When mesh 656 is formed, adjacent braided wires are mutually overlapped to form a movable intersection point, so that four vertexes of mesh 656 can move, the moving range is larger than that of the movable intersection point formed in an interlocking mode, and therefore the embodiment has no excessive limitation on the size of the mesh, can adapt to the implantation of a bridging stent and has a stabilizing effect on the bridging stent even if the mesh size is smaller. In addition, the window support of the present embodiment does not have a structure like a peak or a valley except for the end portion, and when the stent graft of the present embodiment is used to bend a blood vessel, irritation to the blood vessel is less.

As shown in fig. 17, in other embodiments, the window support 75 may include at least two support sections 751, the adjacent support sections 751 are connected to each other by hooking, and each support section may be formed by cross-weaving using woven filaments, i.e., a net-shaped woven structure as shown in fig. 15. At this time, because the adjacent support sections 751 are connected in a mutually hooking mode, a certain stretching allowance can be reserved between the adjacent support sections 751, and the covered stent can better adapt to a bent blood vessel.

Example four

In the first embodiment, the branch stent has a hollow cylindrical structure, and the branch stent of the stent graft of the present embodiment is shown in FIG. 18. Specifically, the branch stent 82 includes a first section 822 and a second section 821 connected to one end of the first section 822, wherein the first section 822 is a cylindrical structure, the second section 821 is a truncated cone structure, and both ends of the branch stent 82 have openings communicated with the inner cavity thereof. Wherein the opening of the first segment 822 is larger than the opening of the second segment 821, and the outer diameter of the second segment 821 is gradually reduced from the opening to the first segment 822 (i.e., the first segment 821 is a flared segment). As shown in FIG. 19, in a cross-section perpendicular to the central axis of the stent graft, the projection of the first segment 822 falls within the projection of the second segment 821. When the branch stent 82 of the present embodiment is disposed between the proximal end of the window and the proximal end of the stent graft (i.e., when the branch stent 82 is in communication with the proximal through hole of the inner stent graft), the end of the first segment 822 opposite the second segment 821 is connected to the folded portion of the inner stent graft, the end of the second segment 821 opposite the first segment 822 is a free end, that is, the first segment 822 is a proximal segment of the branch stent, and the second segment 821 is a distal segment of the branch stent. Conversely, when the branch stent 82 of the present embodiment is disposed between the distal end of the window and the distal end of the stent graft, the first segment 822 is the distal segment of the branch stent and the second segment 821 is the proximal segment of the branch stent.

The branch stent 82 of the embodiment has a first section in a circular truncated cone shape, and a second section with a larger opening is communicated with the through hole of the internal connection tectorial membrane, so that when a branch is selected, a guide wire or a conveyor can more easily enter the branch stent, and the bridging stent can be implanted more quickly.

It is understood that in other embodiments, the branch support 92 may be an open structure. As shown in fig. 20 and 21, the branch stent 92 has a sheet-like structure with an arc-shaped curved surface, and the cross-sectional profile of the branch stent is C-shaped. Wherein two sides between the proximal end and the distal end of the branch stent 92 are connected to the inner surface of the main stent, so that the space enclosed by the branch stent 92 and the inner surface of the main stent forms the lumen of the branch stent 92. Because other tectorial membranes do not exist between the inner cavity of the branch stent 92 and the inner surface of the main stent, the material of the part is reduced, the whole thickness of the part of the tectorial stent is also reduced, and the assembly difficulty of the tectorial stent is correspondingly reduced.

In other embodiments, when it is desired to place two bridging stents at one end of the graft, the branched stent may also take the configuration shown in FIG. 22, i.e., the branched stent has one opening at one end and two openings at the other end. Referring to fig. 22 and 23, the branch stent 102 has a hollow tubular structure including a first section 1021 and a second section 1022. The end of the first section 1021 far from the second section 1022 is provided with one opening, the end of the second section 1022 far from the first section 1021 is provided with two openings, the end of the first section 1021 far from the second section 1022 is connected with the internal connection coating, and the end of the second section 1022 far from the first section 1021 is a free end. Thus, only one branch stent corresponding to the connection with the internal stent graft can be implanted, but two bridge stents can be implanted, thereby avoiding internal leakage caused by suture between openings of the branch stents.

It is understood that in other embodiments, the extension direction of the branched stent disposed at the distal end of the inner graft may be at an angle with respect to the length extension direction of the stent graft, and the angle is greater than 0 degrees; or the branch stent connected with the distal end of the inscribed coating can extend towards the central axis of the coated stent, so that the branch vascular bridging stent on the arch is conveniently implanted, and the bending degree of the bridging stent is reduced.

EXAMPLE five

The stent graft structure of this embodiment is substantially the same as that of the first embodiment, except that the stent graft is inscribed with a membrane. As shown in fig. 24, the internal connection coating film 114 is provided with a supporting unit 116, and the supporting unit 116 makes the bottom of the internal connection coating film at least partially parallel to the plane where the first edge and the second edge of the window are located, or protrudes outwards from the plane, or is concaved inwards relative to the plane.

As shown in fig. 25, in the present embodiment, the supporting unit 116 includes a suture thread, which is fixed to the main body cover 1112 of the main body stent around the second edge after passing from a position on the main body cover adjacent to the first edge of the window as a starting point, through the upper and lower surfaces of the inner cover 114 to the second edge of the window, that is, the suture thread wraps the inner cover and the edges of the main body cover adjacent to the second edge and the first edge of the window. The suture material can be selected from high molecular materials or metal materials, and is preferably thin flexible wire materials, so that the compression loading of the covered stent can not be influenced.

During sewing, a suture thread is pulled out from the inner surface of the main body covering film to penetrate to the outer surface of the main body covering film, passes through the inner connecting covering film from the upper surface of the inner connecting covering film to the lower surface of the inner connecting covering film by bypassing the edge of the main body covering film, then passes through the needle on the inner connecting covering film back and forth, then passes through the inner surface of the inner connecting covering film to the outer surface close to the second edge, then passes through the main body covering film from the outer surface of the main body covering film to the inner surface of the main body covering film by bypassing the edges of the main body covering film and the inner connecting covering film, and finally completes a section of circumferential sewing.

When the thread is threaded back and forth on the upper and lower surfaces of the inner graft film, a plurality of stitching points are formed on the surface of the inner graft film. To reduce the effect of the suture on the guidewire approach before the bridge stent is implanted, the suture points should not be too sparse, and preferably, the distance L2 between two adjacent suture points is less than 2 mm, the distance L3 between the suture point on the internal coating film 114 closest to the first edge or the second edge of the window is also less than 2 mm, and the distance L4 between the suture point on the main body coating film 1112 and the first edge or the second edge of the window is also less than 2 mm.

In addition, the supporting unit 116 enhances the overall stability of the internal connection coating film 114 and reduces the deformation capability of the bottom of the internal connection coating film 114. As shown in fig. 26, the axial length of the internal stent graft 114 in the natural state is denoted by L5, the length of the internal stent graft 114 when it is stretched by a force (for example, when the stent graft is used for bending a blood vessel) is denoted by L6, and the elongation θ is the ratio of the change in length of the internal stent graft 114 before and after stretching to the natural state. Because the supporting unit 116 is arranged, the deformation degree of the internal connection covering film 114 is limited, and the extension rate of the internal connection covering film is less than 0.1 and more than 0.01 in the embodiment, so that the internal connection covering film can adapt to the bent blood vessel without tearing, and the internal connection covering film can be conveniently prevented from being deformed too much and collapsing.

It will be appreciated that in other embodiments, the support element of the inner graft membrane may also be a corrugated support structure similar to the support element of the main body, i.e. the support element is separately formed and attached to the surface of the inner graft membrane by stitching or heat treatment. Alternatively, the support unit may be integrally woven with the window support. Because the wave-shaped supporting structure has certain wave height (namely axial length), the supporting unit has better integrity and better supporting effect on the internal tectorial membrane and the effect of limiting deformation. It will be appreciated that the support unit may also be integrally formed with the body support, or a portion of the support unit may be integrally formed with the body support and a portion of the support unit may be integrally formed with the window support. Or, a part of the supporting unit and the main body supporting piece are integrally formed, and a part of the window supporting piece and the main body supporting piece are integrally formed.

Preferably, the bottom of the inner graft membrane is convex or flat, so that the size of the inner cavity of the main stent at the position where the inner graft membrane is arranged is not too small, and the hemodynamics in the aorta is not affected.

In this embodiment, the internal connection film and the main body film are also formed separately and then spliced, so that the internal connection film is more convenient to manufacture when the supporting unit is arranged on the internal connection film.

It can be understood that, in order to take account of the opening form of the inner-contact film folded portion, the opening of the folded portion may be slightly concave, that is, the folded portion is closer to the central axis of the stent graft than the bottom, and the supporting unit may be disposed only at the bottom of the inner-contact film. Because the axial length of the turnover part is obviously smaller than that of the bottom part, even if the turnover part is concave, the hemodynamics flowing through the inner cavity of the main body bracket can not be influenced.

EXAMPLE six

The stent graft structure of this embodiment is substantially the same as the stent graft structure of the second embodiment, except for the reinforcement of the flap portion. To better maintain the flap in a good open configuration, as shown in FIG. 27, the stent graft of this embodiment includes a reinforcement member 127, and the reinforcement member 127 is disposed at the upper edge 1243 of the flap. In this embodiment, the reinforcing member 127 is a separate closed structure, and is disposed around the opening of the folded portion to support the opening of the folded portion, thereby reducing the deformation capability of the opening. The reinforcing member 127 may be a wave-shaped structure similar to the body support, or a closed structure formed by surrounding a wire. As shown in FIG. 28, when the reinforcement member 127 is in the closed configuration, the portion connected to the upper edge 1243 of the flap portion is curved to conform to the shape of the main stent, and the opposite portion may be concave toward the central axis of the stent graft, may protrude outward from the central axis of the stent graft, or may be parallel to the central axis of the window and the stent graft.

It will be appreciated that in other embodiments, the reinforcing element may be a simple open structure, i.e., the reinforcing element has two circumferential free ends or edges, in which case the projection of the reinforcing element onto a cross-section taken perpendicular to the central axis of the stent graft may be curved or curvilinear, or may be planar or straight. In this case, the reinforcing member may be provided at any section of the opening of the folded portion, that is, may be provided on the upper surface of the folded portion where the upper edge is located (i.e., the upper folded unit), may be provided on the lower surface of the folded portion opposite to the upper edge (i.e., the lower bottom unit), or may span the upper surface and the lower surface.

It will also be appreciated that the reinforcing member may be formed separately, integrally with the window support, or integrally with the body support.

The above-mentioned specific embodiments are only some embodiments of the present invention, and do not limit the present invention, and this description may not exhaust all embodiments of the inventive concept, and some features of the above-mentioned different embodiments may be replaced or combined with each other, and those skilled in the art may also make simple replacement according to actual needs, and the inventive concept is subject to the protection scope claimed.

Claims

1. The covered stent comprises a main body covered membrane, wherein a window is formed in the surface of the main body covered membrane, and the covered stent is characterized by further comprising an internal connection covered membrane, the edge of the internal connection covered membrane is connected with the main body covered membrane, and the internal connection covered membrane is connected with the main body covered membrane through splicing after being formed independently.

2. The stent graft of claim 1, wherein the window comprises a first edge and a second edge extending along a length extension direction of the stent graft, the inner graft comprises a bottom portion between the first edge and the second edge, and a support unit is arranged on the inner graft and enables the bottom portion to be at least partially convex outwards or partially concave inwards or parallel to a plane in which the first edge and the second edge are located.

3. The stent graft of claim 2, wherein the supporting unit comprises a suture, and the suture passes through the upper and lower surfaces of the inner cover membrane to the second edge after passing around the first edge and the edge of the inner cover membrane, and then passes around the second edge and the other edge of the inner cover membrane to connect the inner cover membrane and the main body stent.

4. The stent graft as recited in claim 1, wherein the extension ratio of the inner graft is greater than 0.01 and less than 0.1.

5. The stent graft of claim 2, wherein the support unit comprises a corrugated support structure coupled to a surface of the inner graft.

6. The stent graft of claim 5, wherein the stent graft includes a window support member disposed outside the inner graft and protruding outwardly from a surface of the inner graft, and the undulating support structure is integrally formed with the window support member.

7. The stent graft of claim 2, wherein the inner graft membrane comprises a base, a proximal fold and a distal fold, the proximal fold and the distal fold being disposed at respective ends of the base, at least one of the proximal fold and the distal fold being disposed on an inner surface of the main body membrane; the supporting unit is arranged at the bottom, and the folding part is closer to the central axis of the covered stent than the bottom.

8. The stent graft of any one of claims 6 or 7, wherein the surface of the window support is formed with a sinker segment, the sinker segment being located in a cross-section of the stent graft that has a smaller area than the cross-section of other portions of the stent graft that are distal from the sinker segment.

9. The stent graft of any one of claims 6 or 7, further comprising a body support coupled to the body cover, wherein the window support is part of the body support and has a circumferential aspect ratio that is less than a circumferential aspect ratio of the body support in the same cross-section.

10. The stent graft of any one of claims 6 or 7, wherein the window support comprises a mesh structure having mesh openings, the size of the mesh openings being variable by an external force.

11. The stent graft of any one of claims 6 or 7, wherein the proximal end and/or the distal end of the window support extends beyond the edge of the window in the length direction of the stent graft.