Covered stent

Abstract

The present invention provides a covered stent, which includes a main stent. A window is formed on the surface of the main stent. The covered stent further includes an inner connecting film, the edge of the inner connecting film is connected to the main stent, and through holes communicating with the inner cavity of the covered stent are also formed on the inner connecting film; the covered stent further includes a window support member, the window support member is arranged outside the inner connecting film and protrudes outward from the surface of the inner connecting film, the window support member includes a mesh structure having mesh holes, and the size of the mesh holes can be changed by an external force. The covered stent provided by the present invention can adapt to the implantation of bridging stents of different sizes, and the braided wires will not squeeze the bridging stents. To a certain extent, the position of the bridging stents can also be fixed, enhancing the stability against blood flow impact after the implantation of the bridging stents.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and particularly to a covered stent. Background Art

[0002] Aortic aneurysm and aortic dissection are currently diseases that seriously endanger human life safety. If not actively treated, the aortic aneurysm and dissection will continue to expand and finally rupture, causing serious complications and death. With the continuous increase in the number of patients with hypertension, hyperlipidemia and hyperglycemia, the current incidence of aortic aneurysm and aortic dissection is also increasing significantly.

[0003] Traditional open surgery for treating aortic aneurysm and aortic dissection has the disadvantages of large trauma, high mortality, long operation time, high incidence of postoperative complications and high operation difficulty. Endovascular treatment has gradually become the main method for treating aortic aneurysm and aortic dissection at present due to its advantages of small trauma, few postoperative complications, short operation time and low operation difficulty. By implanting a covered stent in the aorta, the vascular lesion is isolated outside the covered stent, and the blood flow is restricted to flow through the inside of the covered stent, so as to achieve the purpose of protecting the blood vessel. Since it is necessary to ensure the fixation of the implanted covered stent and prevent the blood flow from flowing into the blood vessel through the proximal and distal ends of the stent, the covered stent requires an anchoring zone of a certain length. Therefore, when the aortic aneurysm or dissection involves the branch artery, the implantation of the covered stent for treatment will block the branch artery to varying degrees, and even the endovascular technique cannot be used for treatment.

[0004] For the endovascular treatment of aortic aneurysm or dissection involving branch arteries, in order to realize the blood supply of the branch arteries, the fenestrated stent technique and the chimney stent technique are mostly adopted. The fenestrated stent technique is to make side holes on the stent by means of external or in-situ fenestration of the covered stent. The position of the side hole corresponds to the opening position of the branch artery. During the operation, the stent is implanted, and the opening position is aligned with the branch artery, and then a bridging stent is implanted through the branch artery to cooperate with the covered stent; the chimney stent technique is to implant a bridging stent through the branch artery to cooperate with the covered stent after implanting the covered stent. Generally, the fenestrated stent technique has a high positioning difficulty, requires customization, takes a long time, and cannot be used for emergency treatment; the chimney stent technique is prone to endoleakage, and is limited by the vascular anatomical morphology, and the difficulty of reconstructing multiple branch arteries is high. At the same time, whether the fenestrated stent or the chimney stent technique is adopted, the branch artery is always in an ischemic state before the reconstruction of the branch artery, and the probability of postoperative complications is relatively high. Summary of the Invention

[0005] In view of the above problems, the present invention provides a covered stent, including a main stent, a window is formed on the surface of the main stent, the covered stent further includes an inner connecting film, the edge of the inner connecting film is connected to the main stent, and a through hole communicating with the inner cavity of the covered stent is further formed on the inner connecting film; the covered stent further includes a window support member, the window support member is arranged outside the inner connecting film and protrudes outward from the surface of the inner connecting film, the window support member includes a mesh structure having mesh holes, and the size of the mesh holes can be changed by an external force.

[0006] In one embodiment, the window support member includes a portion formed by cross-weaving of braided wires, and the intersection points of the braided wires are movable.

[0007] In one embodiment, the window support member includes at least two support segments, the support segments are formed by cross-weaving of braided wires, and the at least two support segments are movably connected by hooking each other.

[0008] In one embodiment, the portion of the support segment formed by cross-weaving of braided wires is located at the proximal end and / or the distal end of the window support member.

[0009] In one embodiment, in the mesh structure, the aperture of the mesh holes near the proximal end and / or the distal end of the window is larger than the aperture of the mesh holes in other parts.

[0010] In one embodiment, the main stent includes a main support member, a part of the main support member is located on the other side of the inner connecting film opposite to the window support member, and the weaving density of the window support member is greater than the weaving density of the main support member in the main support member opposite to the window support member.

[0011] In one embodiment, the inner connecting film includes a bottom, a proximal folding portion and a distal folding portion, the proximal folding portion and the distal folding portion are respectively arranged at both ends of the bottom, and at least one of the proximal folding portion and the distal folding portion is arranged on the inner surface of the main stent and is recessed towards the inner cavity of the main stent to form a receiving cavity.

[0012] In one embodiment, the proximal end and / or the distal end of the window support member extends beyond the edge of the window in the length direction of the covered stent.

[0013] In one embodiment, a sinking section is formed on the surface of the window support member, and the cross-sectional area of the covered stent where the sinking section is located is smaller than the cross-sectional area of other parts of the covered stent away from the sinking section.

[0014] In one embodiment, the main stent includes a main covering film, a window is formed on the surface of the main covering film, and the inner connecting film and the main covering film are separately formed and then spliced and connected.

[0015] The covered stent provided by the present invention can effectively isolate aortic dissection and aortic aneurysm involving aortic branch arteries, effectively reconstruct the blood supply of branch arteries, avoid long-term ischemia of branch arteries, has a small surgical difficulty, does not need to be customized, and can be used for emergency treatment. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the overall structure of the covered stent according to an embodiment of the present invention, including a main body stent, a branch stent, and an internal connecting film;

[0017] Figure 2 For Figure 1 It is a schematic diagram of the main body stent structure in the shown covered stent;

[0018] Figure 3 For Figure 1 It is a schematic diagram after the internal connecting film and the branch stent in the shown covered stent are connected;

[0019] Figure 4 For Figure 1 It is a schematic diagram of the internal connecting film structure in the shown covered stent;

[0020] Figure 5 For Figure 4 It is a side view of the internal connecting film shown;

[0021] Figure 6 It shows Figure 1 It is a top view of the shown covered stent, with some structures omitted in the figure;

[0022] Figure 7 It is a partial structure schematic diagram of the covered stent according to another embodiment of the present invention;

[0023] Figure 8 It is a partial structure schematic diagram of the covered stent according to still another embodiment of the present invention;

[0024] Figure 9 It is a schematic diagram after the covered stent of the present invention is implanted into the aneurysm blood vessel;

[0025] Figure 10 It is a schematic diagram of the structure of the covered stent according to an embodiment of the present invention, including a window support;

[0026] Figure 11 For Figure 10 It is a schematic diagram of the structure of the shown window support;

[0027] Figure 12 For Figure 11 It is a partial structure schematic diagram of the shown window support;

[0028] Figure 13Schematic diagram of the contour of the window support of the covered stent according to another embodiment of the present invention;

[0029] Figure 14 is Figure 13 Schematic diagram of the cross-sectional contour of the covered stent shown;

[0030] Figure 15 Schematic diagram of the structure of the window support of the covered stent according to an embodiment of the present invention;

[0031] Figure 16 is Figure 15 Enlarged schematic diagram of the partial structure of the window support shown;

[0032] Figure 17 Schematic diagram of the structure of the window support of the covered stent according to another embodiment of the present invention;

[0033] Figure 18 Schematic diagram of the branch stent structure of the covered stent according to an embodiment of the present invention;

[0034] Figure 19 is included Figure 18 Side view of the covered stent including the branch stent shown;

[0035] Figure 20 Schematic diagram of the branch stent structure of the covered stent according to another embodiment of the present invention;

[0036] Figure 21 is included Figure 20 Side view of the covered stent including the branch stent shown;

[0037] Figure 22 Schematic diagram of the branch stent structure of the covered stent according to yet another embodiment of the present invention;

[0038] Figure 23 is included Figure 22 Side view of the covered stent including the branch stent shown;

[0039] Figure 24 Schematic diagram of a partial structure of the covered stent according to an embodiment of the present invention;

[0040] Figure 25 Figure 24 Schematic diagram of the partial structure of the covered stent shown;

[0041] Figure 26 Schematic diagram of the states before and after stretching of the inner circumscribed covered film;

[0042] Figure 27 Schematic diagram of a partial structure of the covered stent according to an embodiment of the present invention, including a reinforcing member;

[0043] Figure 28 isFigure 27 Several deformation structures of the reinforcing member shown. Specific implementation mode

[0044] To better understand the concept of the present invention, the following specifically describes the implementation mode of the present invention with reference to the accompanying drawings. The following specific embodiments are only partial embodiments of the present invention and do not limit the present invention.

[0045] For the covered stent of the present invention, the end where blood flows in is defined as the "proximal end", and the end where blood flows out is defined as the "distal end". That is, during use, blood flows from the proximal end to the distal end of the covered stent.

[0046] Embodiment 1

[0047] As Figure 1 shown, the covered stent 10 of this embodiment is an overall hollow tubular structure with openings at both ends, including a main stent 11, a branch stent 12, an inner connecting film 14, and a window support member 15. Among them, a window 13 is provided on the surface of the main stent 11, and the edge of the inner connecting film 14 is connected to the main stent 1; the window support member 15 is arranged outside the inner connecting film 14 and protrudes outward from the surface of the inner connecting film 14. A through hole is opened on the inner connecting film 14, and the through hole communicates with the inner cavity of the covered stent 10; as Figure 3 shown, the branch stent 12 is a hollow cylindrical structure, arranged inside the covered stent 10 and communicating with the through hole on the inner connecting film 14, so that blood can flow into the branch blood vessel after passing through the branch stent 12. In this embodiment, the covered stent 10 includes 3 branch stents 12. Among them, two branch stents 12 are arranged near the proximal end of the window 13, and one branch stent 12 is arranged near the distal end of the window 13.

[0048] As Figure 2 shown, the main stent 11 includes a main support member 111 and a main film 112, and the main support member 111 is arranged on the surface of the main film 112. It should be understood that the main support member 111 can be arranged on the inner surface of the main film 112, or on the outer surface of the main film, or a part of the main support member is arranged on the outer surface of the main film, and another part of the main support member is arranged on the inner surface of the main film.

[0049] The window 13 is opened on the main body film 112 and in the middle of the main body film 112. That is to say, there are still the main body support member 111 and the main body film 112 between the end of the window 13 and the end of the main body bracket 11. In this embodiment, the edge formed by the window 13 on the main body film 112 is rectangular, that is, when the main body film 112 is unfolded along the generatrix not passing 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, and the four edges enclose the window 13. Among them, the first edge 131 and the second edge 132 are opposite and are in the same direction as the length extension direction of the film bracket 10, and the third edge 133 and the fourth edge 134 are opposite and are closer to the end of the film bracket 10 than the first edge 131 and the second edge 132. It can be understood that in other embodiments, the window can also be other shapes, as long as the first edge and the second edge extend along the length extension direction of the film bracket. For example, it can form a certain angle with the length extension direction of the film bracket (such as the window is trapezoidal), or the first edge and the second edge are arc-shaped (such as the window is similar to an ellipse). The present invention does not limit the specific shape of the window. It can also be understood that the window can be close to the proximal end of the film bracket or close to the distal end of the film bracket.

[0050] As Figure 1 and Figure 4 shown, the film bracket 10 of this embodiment includes an inner film 14, and the edge of the inner film 14 is connected to the edge of the window. Specifically, the inner film 14 includes a bottom 141 and a folding part 142, and the folding part 142 is arranged at the end of the bottom 141. Among them, the folding part 142 is arranged on the inner surface of the main body bracket, and the folding part 142 is recessed towards the inner cavity of the main body bracket 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 bottom unit 1422 connected to the bottom 141. The side edges of the upper folding unit 1421 and the lower bottom unit 1422 are connected and jointly enclose the receiving cavity 144.

[0051] It can be understood that in other embodiments, the edge of the inner film can also be connected to the inner surface of the main body film.

[0052] As Figure 5 shown, the inner film 14 is also provided with a through hole 147 communicating with the inner cavity of the main body bracket, and the through hole 147 is opposite to the opening of the film bracket 10 and also opposite to the opening of the receiving cavity 144. Since the folding part is provided with a receiving cavity, when establishing the implantation path of the bridging stent, the guide wire or catheter can extend into the branch stent along the receiving cavity, so that the implantation path of the bridging stent can be quickly established and the operation time can be shortened.

[0053] Refer to againFigure 4 In this embodiment, the inner coating 14 is provided with two folding parts 142 (including a proximal folding part and a distal folding part respectively provided at the proximal end and the distal end of the inner coating), and both folding parts 142 are provided with through holes 147, wherein the proximal folding part 142 is provided with two through holes, and the distal folding part 142 is provided with one through hole. In this embodiment, the folding part is formed by folding the end of the inner coating 14 back, specifically, by folding the end of the inner coating 14 away from the bottom 141 and toward the inner surface of the main support 11. It can be understood that the structures of the two folding parts of this embodiment can be completely the same or slightly different.

[0054] When the coated stent of the present invention is used for curved blood vessels, in order to reduce the tension of the internal coating due to adapting to the curvature of the blood vessel, the angle between the extension direction of the braided wire of the internal coating and the extension direction of the length of the coated stent can be set to be greater than 0 degrees.

[0055] It is understandable that in other embodiments, the inner coating may only be provided with a folded portion at the proximal end, and the number of through holes may be 1 to 3. In the present invention, the position and number of the branch stents 12 correspond to the position and number of the through holes, that is, when one end of the inner coating is provided with a plurality of through holes, correspondingly, the same number of branch stents 12 are also provided at this end of the inner coating, and the through holes may be staggered or provided on the same cross section perpendicular to the central axis of the coating stent.

[0056] It can also be understood that, in other embodiments, the folded portion with the receiving cavity can be separately manufactured into a pocket-shaped structure with the receiving cavity and then connected to the bottom and the edge of the window respectively.

[0057] It is also understandable that in other embodiments, only one folded portion may form the receiving cavity, and the other folded portion is merely an inclined surface transitioning from the bottom to the inner surface of the main support. Of course, a through hole may still be provided on this inclined surface. It is also understandable that the through hole may also be provided on the bottom.

[0058] In this embodiment, the inner coating 14 and the main body coating 112 are formed separately and then connected by sutures. In other embodiments, the two can also be connected by bonding or other methods. Since the inner coating is also provided with a branch bracket, the inner coating and the main body coating are formed separately and then spliced, which can greatly reduce the difficulty of production. It is understandable that in other embodiments, when the inner coating is not provided with a folding portion and a branch bracket, the inner coating can also be formed integrally with the main body coating.

[0059] Back again Figure 4 and Figure 5, the inner cavity of the folding part 142 of this embodiment (i.e., the size of the receiving cavity) gradually decreases from the opening position towards the through hole 147 (i.e., gradually decreases towards the direction of the opening of the end of the covered stent), so that when implanting the bridging stent, the guide wire can more quickly enter the branch stent along the receiving cavity of 3.

[0060] Returning again to Figure 1 and Figure 2 , a window support 15 is also provided on the window 13 of the covered stent 10. The cross-section of the window support 15 is in an arched structure and is arranged above the inner covered film 14, protruding outwards from the surface of the inner covered film 14. In this embodiment, the window support 15 is integrally formed with a part of the main body support 111. That is to say, the window support 15 is a part of the main body support 111. During preparation, a window is first opened on the main body covered film, and then the main body support 111 is connected to the main body covered film. Among them, the main body support exposed at the window part constitutes the window support. And preferably, the circumferential proportion of the window support in this embodiment is smaller than that of the main body support. That is to say, on the same cross-section, the proportion of the window support in the perimeter of the cross-section is smaller than the proportion of the main body support in the perimeter of the cross-section. In this way, it can be ensured that the inner cavity size of the main body stent at the position where the inner covered film is provided is not too small, so as not to affect the hemodynamics in the aorta. It can be understood that in other embodiments, the circumferential proportion of the window support can also be equal to or greater than that of the main body support.

[0061] As Figure 6 shown, the window support 15 of this embodiment includes a plurality of support segments 151, and the plurality of support segments 151 are axially spaced apart. The support segments 151 are connected to the main body stent 11 in the circumferential direction ( Figure 6 only a partial structure of the main body stent is shown). In this embodiment, the support segment 151 includes a plurality of Z-shaped structures connected end to end, and the Z-shaped structure has a wave crest and a wave trough. The axial distance between the wave crest and the wave trough is the wave height of the Z-shaped structure. In order to better implant the bridging stent into the branch stent for cooperation and minimize the interference and blockage of the window support to the bridging stent, in the window support 15 of this embodiment, the distance between the wave crest 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 can be ensured that when implanting the bridging stent, it is not necessary to specifically select between the wave trough of the support segment 151 and the third edge 133. Similarly, the distance between the wave trough of the support segment close to the fourth edge of the window and the fourth edge can also be selected as 10-20 mm. It can be understood that in other embodiments, when it is possible to accurately select to place the bridging stent between the wave trough of the support segment and the third edge, the distance between the wave crest of the support segment close to the third edge of the window and the third edge can also be not limited. At this time, the wave height of the support segment can be preferably 6-12 mm. Among them, Figure 6Reference numeral 01 in the figure shows the placement positions of some optional bridging brackets. In other embodiments, the implantation position of the bridging bracket can also be optimized by changing the wave height of the support section. For example, the wave height of the support section near the third edge and / or the fourth edge can be set higher than that of other support sections, or a support section with a higher wave height can be set at the position where the bridging bracket needs to be placed, not limited to the support sections near the third edge and the fourth edge.

[0062] It can be understood that in other embodiments, two adjacent support sections near the through hole of the inner lining film are in a reverse structure, that is to say, among the two adjacent support sections, the wave crest of one support section is opposite to the wave trough of the other support section. In this way, when selecting the implantation position of the bridging bracket, the position between the opposite wave crest and wave trough can be selected.

[0063] As Figure 6 shown, in this embodiment, the third edge 133 of the window 13 is located between the window support 15 and the main body support 111, and the upper edge 143 of the folding part 142 is connected to the third edge 133. At this time, in order to keep the folding part 142 in a good opening shape, a reinforcing member can be provided on the opening of the folding part 142. For example, stitches can be added or reduced on the upper edge 143 to appropriately reduce the deformation ability of the upper edge 143. It can be understood that in other embodiments, the third edge can also partially coincide with the main body support or the window support (that is, the support section partially covers the third edge of the window). At this time, the opening edge (that is, the upper edge) of the receiving cavity also partially coincides with the main body support or the window support. That is to say, in a plane parallel to the bottom of the inner lining film, the projections of the third edge and the upper edge of the receiving cavity coincide with the main body support or the window support. At this time, the main body support or the window support can also play the role of supporting the opening of the receiving cavity of the folding part, which is equivalent to the role of the reinforcing member. It can also be understood that in other embodiments, a reinforcing member can also be provided separately, which will be described in detail later.

[0064] In other embodiments, such as Figure 7As shown, the stent graft may also include a connector 252, which is arranged above the window 23, and a plurality of support segments 251 are connected by the connector 252. In addition, the proximal end and / or distal end of the connector 252 may also extend to the main support member 211 and be connected to the main support member 211. The connector 252 is preferably connected to the crest of the adjacent support segment 251. More preferably, when the stent graft is implanted into a curved blood vessel, the connector is located exactly on the large curved side of the stent graft. In this embodiment, the connector 252 is a connecting rod, and the length extension direction of the connector 252 is consistent with the extension direction of the stent graft. It is understood that in other embodiments, the connector may only connect the support segment of the window support member without extending to the main support. The material of the connector may be selected from medical metal materials, such as superelastic nickel titanium wire, medical stainless steel wire, etc. The connector and the support segment may be connected by crimping or welding. It is understood that in other embodiments, the connector may also have a certain angle with the length direction of the stent graft. By setting up a connector, mutual interference between support segments can be reduced, while avoiding shortening of the stent, improving the overall support performance of the window support, and also ensuring that when the coated stent is used in a curved blood vessel, due to the limitation of the connector, the crest of the support segment 251 will not rise, thereby better adapting to the curved shape of the blood vessel.

[0065] In other embodiments, Figure 8 As shown, the connector 352 may include a plurality of segments 353, two adjacent segments 353 are staggered, and two adjacent support segments are connected by a segment 353. In this case, the segment 353 may be connected to any position of the two adjacent support segments, and preferably the extension direction of the segment 353 is consistent with the extension direction of the stent graft. Of course, the plurality of segments may also be staggered, which is equivalent to Figure 7 The connector shown includes a plurality of segments. When the connector includes a plurality of segments arranged in a staggered manner, the selection of the insertion site of the bridging stent is more flexible, and the implanted bridging stent has a better matching morphology with the branch vessel.

[0066] like Figure 9As shown in the figure, the covered stent 10 of the present invention can be used for endovascular treatment of aortic arch aneurysms and treatment of thoracoabdominal aortic aneurysms. Since the window of the covered stent 10 of the present invention is provided with a window support member, it can provide good radial support force. Especially when used for treating dissecting aneurysms, even if the true lumen is small, the covered stent 10 can provide good radial support force before the bridging stent 100 is implanted. Especially when the covered stent 10 of the present invention is used in curved blood vessels, after the covered stent 10 adapts to the curvature of the blood vessel morphology, due to the existence of the window support member, the space between the window and the blood vessel wall will not be overly squeezed, thus reserving sufficient space for the implantation of the bridging stent 100. In addition, it can always maintain the blood flow supply of the branch blood vessels before the bridging stent 100 is implanted, greatly reducing the probability of ischemic complications after the operation, and at the same time providing the doctor with sufficient operation time.

[0067] Embodiment 2

[0068] As Figure 10 shown, the structure of the covered stent 40 in this embodiment is substantially the same as that of the covered stent 10 in Embodiment 1, the difference being the window support member 45. The window support member 45 in this embodiment is formed separately, and the main body support member 411 opposite to the window support member 45 has an open structure. That is to say, the support members of other parts of the main body stent are of a closed annular structure, while the main body support member 411 opposite to the window support member 45 is not a complete ring.

[0069] As Figure 11 and Figure 12 shown, the window support member 45 in this embodiment includes a plurality of support segments 451. The plurality of support segments 451 are connected to the edge of the window 43 of the main body stent, and the plurality of support segments 451 are connected to each other by hooking, thereby forming a mesh structure with mesh holes 456. This mesh structure includes a part formed by braiding braided wires, and the intersection points of the braided wires form the vertices of the mesh holes 456. The vertices of the mesh holes 456 are formed by the braided wires through mutual pressing or mutual hanging, so that the intersection points of the braided wires are movable. Therefore, the size of the mesh holes can change under external force. For example, when implanting a bridging stent, the outer diameter of the sheath of the delivery device is larger than the mesh holes. At this time, the size of the mesh holes can become larger under the extrusion of the sheath, or when the outer diameter of the implanted bridging stent is larger than the size of the mesh holes, the braided wires will not squeeze the bridging stent, and to a certain extent, it can also fix the position of the bridging stent, increasing the stability of the bridging stent against blood flow impact after implantation and being able to adapt to the implantation of bridging stents of different sizes.

[0070] As Figure 12As shown, two adjacent support segments 451 are connected by hooking each other. That is to say, the peak of one support segment 451 is hooked to the valley of an adjacent support segment 451. The height h of a single support segment 451 ranges from 6 to 20 millimeters, and the distance L0 between adjacent peaks or valleys of a single support segment 451 is between 10 and 25 millimeters, which can ensure that the space is not too small when the bridging stent is implanted. There is a certain distance h0 between the peak and valley of two support segments 451 that are hooked to each other, and this distance is between 0 and 5 millimeters. In this way, a certain stretching distance can be left between adjacent support segments. When the covered stent of this embodiment is implanted into a curved blood vessel, the window support member faces the major curvature side. Thus, there can also be a certain stretching margin between multiple support segments 451, and the covered stent can better adapt to the curved blood vessel.

[0071] Preferably, in the circumferential direction, two overlapping support rings are included on the same support segment 451, so that the mesh holes of the mesh structure are diamond-shaped, which also enhances the wall attachment and support of the window support member to a certain extent. It can be understood that in other embodiments, multiple overlapping support rings can be included on the same support segment. When there are more support rings, the size of the mesh holes is smaller. Therefore, it is preferred that the number of overlapping support rings on the same support segment is 2 to 4.

[0072] In this embodiment, the window support member 45 partially overlaps with the main film of the main stent to facilitate suturing the window support member. At the same time, the window support member at the opening part of the receiving cavity near the folding part can also act as a reinforcing member to ensure a good opening shape. It can be understood that in other embodiments, the window support member may not overlap with the main film at all. In this case, it can also be directly sutured with a suture.

[0073] It can also be understood that in other embodiments, the sum of the cross-sectional perimeters of the window support member and the cross-sectional perimeter of the relative main stent is greater than the perimeter of the film at this cross-section. That is to say, there is partial overlap between the window support member and the main support member in the circumferential direction. In this way, the wall attachment and the support force at the positions of the first and second edges of the window can be appropriately enhanced, and the covered stent is not easily collapsed.

[0074] In this embodiment, the window support member 45 has a natural transition with the surface of the main stent. That is to say, basically, the cross-sections of any cross-section of the covered stent 40 are substantially equal.

[0075] Such as Figure 13 and Figure 14As shown, in other embodiments, a sunken section 554 is formed on the surface of the window support 55. The sunken section 554 is closer to the inner-joined film than other parts of the window support 55. Thus, the cross-sectional area of the film stent where the sunken section 554 is located is smaller than the cross-sectional areas of other parts of the film stent away from the sunken section 554. Transition sections 555 and connection sections 556 are further provided at both ends connected to the sunken section 554. Among them, the transition section 555 is an inclined surface and is arranged between the sunken section 554 and the connection section 556. The connection section 556 is connected to the main stent and is in the same curved surface as the outer surface of the main stent. It can be understood that in other embodiments, the connection section may not be included. In this case, the other end of the transition section is directly connected to the main stent; or, in other embodiments, the transition section is a vertical surface. When there is a sunken section in the window support of the film stent, after the film stent is implanted into a curved blood vessel, the deformation amount of the window support is small, and the extrusion by the blood vessel wall on the large bend side of the blood vessel is relatively small. Thus, the reaction force of the window support on the blood vessel wall is also reduced, making the long-term effect better after the reconstruction of the diseased blood vessel, and problems such as secondary rupture are not likely to occur.

[0076] In other embodiments, the window support and the opposite main support can also be integrally braided. At this time, the braiding density of the window support can be controlled to be greater than that of the opposite main support. In this way, the compliance of the overall film stent (especially the position where the window is opened) can be improved, and at the same time, the wall attachment property of the positions where the first edge and the second edge of the window are located can also be improved. Of course, in other embodiments, the window support and the opposite main support can also be braided separately, and the braiding density of the window support is greater than that of the opposite main support.

[0077] Embodiment III

[0078] The film stent structure of this embodiment is generally the same as that of the film stent structure in Embodiment II, with the difference lying in the window support 65. As Figure 15 and Figure 16 shown, the window support 65 of this embodiment is formed by cross-braiding of braiding wires 657, and the mesh holes 656 are in a diamond structure. When forming the mesh holes 656, adjacent braiding wires overlap with each other to form movable intersection points. Thus, all four vertices of the mesh holes 656 can move, and the movement range is larger than that of the movable intersection points formed by the interlocking method. Thus, there are not many restrictions on the size of the mesh holes in this embodiment. Even if the mesh hole size is small, it can still adapt to the implantation of the bridging stent and play a stabilizing role on the bridging stent. In addition, there is no structure similar to wave peaks or wave valleys in the window support of this embodiment except at the ends. When the film stent of this embodiment is used for a curved blood vessel, the stimulation to the blood vessel is smaller.

[0079] As Figure 17As shown, in other embodiments, the window support 75 may include at least two support segments 751, which are connected to each other in a hooked manner. Each support segment may be formed by cross-weaving braided wires, that is, as Figure 15 shown in the mesh braided structure. At this time, since the adjacent support segments 751 are connected to each other in a hooked manner, there may be a certain stretching margin between the adjacent support segments 751, and the covered stent can better adapt to the curved blood vessel.

[0080] Embodiment Four

[0081] In Embodiment One, the branch stent has a hollow cylindrical structure. The branch stent of the covered stent in this embodiment is as Figure 18 shown. Specifically, the branch stent 82 includes a first segment 822 and a second segment 821 connected to one end of the first segment 822. The first segment 822 has a cylindrical structure, and the second segment 821 has a frustum-shaped structure. Both ends of the branch stent 82 have openings communicating with its inner cavity. The opening of the first segment 822 is larger than that of the second segment 821, and the outer diameter of the second segment 821 gradually decreases during the process of extending from the opening towards the first segment 822 (that is, the first segment 821 is a flared segment). As Figure 19 shown, in the cross-section perpendicular to the central axis of the covered stent, the projection of the first segment 822 falls within the projection of the second segment 821. When the branch stent 82 of this embodiment is arranged between the proximal end of the window and the proximal end of the covered stent (that is, when the branch stent 82 communicates with the proximal through-hole of the inner covered membrane), one end of the first segment 822 opposite to the second segment 821 is connected to the folded portion of the inner covered membrane, and one end of the second segment 821 opposite to the first segment 822 is a free end. That is, the first segment 822 is the proximal segment of the branch stent, and the second segment 821 is the distal segment of the branch stent. On the contrary, when the branch stent 82 of this embodiment is arranged between the distal end of the window and the distal end of the covered stent, 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.

[0082] The branch stent 82 of this embodiment has a first segment in the shape of a frustum, and the second segment with a larger opening communicates with the through-hole of the inner covered membrane. Thus, when selecting a branch, the guide wire or the delivery device can more easily enter the branch stent, and the bridging stent can be implanted more quickly.

[0083] It can be understood that in other embodiments, the branch stent 92 may also be an open structure. As Figure 20 and Figure 21As shown, the branch stent 92 is a sheet-like structure with an arc-shaped curved surface, and the cross-sectional profile of the branch stent is C-shaped. Among them, 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. Thus, the space enclosed by the branch stent 92 and the inner surface of the main stent forms the inner cavity of the branch stent 92. Since there is no other film between the inner cavity of the branch stent 92 and the inner surface of the main stent, the material of this part is reduced, and the overall thickness of this part of the covered stent is reduced, and the assembly difficulty of the covered stent is correspondingly reduced.

[0084] In other embodiments, when it is necessary to place two bridging stents at one end of the inner-inserted film, the branch stent can also be Figure 22 the structure shown, that is, one end of the branch stent has one opening and the other end has two openings. Combining Figure 22 and Figure 23 , the branch stent 102 is generally a hollow tubular structure, including a first section 1021 and a second section 1022. Among them, the end of the first section 1021 far from the second section 1022 has one opening, the end of the second section 1022 far from the first section 1021 has two openings, and the end of the first section 1021 far from the second section 1022 is connected to the inner-inserted film, and the end of the second section 1022 far from the first section 1021 is a free end. In this way, it is equivalent to that only one branch stent is connected to the inner-inserted film, but two bridging stents can still be implanted, thus avoiding internal leakage caused by suturing between the openings of the branch stent.

[0085] It can be understood that in other embodiments, the extending direction of the branch stent provided at the distal end of the inner-inserted film can form a certain angle with the length extending direction of the covered stent, and the included angle is greater than 0 degrees; or, the branch stent connected to the distal end of the inner-inserted film can extend towards the central axis of the covered stent, so as to facilitate the implantation of the bridging stent for the branch blood vessel above the arch and reduce the bending degree of the bridging stent.

[0086] Embodiment Five

[0087] The structure of the covered stent in this embodiment is substantially the same as that in Embodiment One, the difference being the inner-inserted film. As Figure 24 shown, a support unit 116 is provided on the inner-inserted film 114, and the support unit 116 makes at least part of the bottom of the inner-inserted film parallel to the plane where the first edge and the second edge of the window are located, or protrude outwards from this plane, or be concave with respect to this plane.

[0088] As Figure 25As shown, in this embodiment, the support unit 116 includes sutures. The sutures start from a position adjacent to the first edge of the window on the main body membrane, then pass through the upper and lower surfaces of the inner membrane 114 and reach the second edge of the window, and then bypass the second edge and are fixed to the main body membrane 1112 of the main body stent. That is to say, the sutures surround the inner membrane and the edges of the main body membrane adjacent to the second edge and the first edge of the window. The suture material can be selected from polymer materials or metal materials, preferably a thinner flexible wire material, so as not to affect the compression loading of the membrane stent.

[0089] During suturing, the suture starts from the inner surface of the main body membrane and passes through to the outer surface of the main body membrane, then bypasses the edge of the main body membrane and passes from the upper surface of the inner membrane through the inner membrane to the lower surface of the inner membrane, and then passes the needle back and forth on the inner membrane. Then, the suture passes from the inner surface of the inner membrane to the outer surface near the second edge, and then the suture bypasses the edges of the main body membrane and the inner membrane and passes through the main body membrane from the outer surface of the main body membrane to the inner surface of the main body membrane, thus completing one circumferential suture.

[0090] When the suture passes back and forth on the upper and lower surfaces of the inner membrane, a plurality of suture points are formed on the surface of the inner membrane. To reduce the influence of the suture on the guide wire access before the implantation of the bridging stent, the suture points should not be too sparse. Preferably, the distance L2 between two adjacent suture points is less than 2 mm, and the distance L3 between the suture point closest to the first edge or the second edge of the window on the inner membrane 114 is also less than 2 mm, and the distance L4 between the suture point on the main body membrane 1112 and the first edge or the second edge of the window is also less than 2 mm.

[0091] In addition, the support unit 116 enhances the overall stability of the inner membrane 114 and reduces the deformation ability of the bottom of the inner membrane 114. As Figure 26 shown, the axial length of the inner membrane 114 in the natural state is denoted as L5, and the length of the inner membrane 114 when it is stretched by force (for example, when the membrane stent is used for a curved blood vessel) is L6. The elongation rate θ is the ratio of the change in length of the inner membrane 114 before and after stretching to the natural state. Due to the presence of the support unit 116, the degree of deformation of the inner membrane 114 is limited. In this embodiment, the elongation rate of the inner membrane is less than 0.1 and greater than 0.01. In this way, on the one hand, the inner membrane can adapt to the curved blood vessel without tearing, and on the other hand, it can also ensure that it will not deform too much and collapse.

[0092] It can be understood that in other embodiments, the support unit of the inner lining film can also be a corrugated support structure similar to the main body support unit. That is to say, after the support unit is separately formed, it is connected to the surface of the inner lining film by stitching or heat treatment. Alternatively, the support unit can also be integrally woven with the window support member. Since the corrugated support structure has a certain wave height (i.e., axial length), the integrity of the support unit is better, and the support effect on the inner lining film and the effect of restricting deformation are better. It can be understood that the support unit can also be integrally formed with the main body support member, or a part of the support unit is integrally formed with the main body support member, and a part of the support unit is integrally formed with the window support member. Or, a part of the support unit is integrally formed with the main body support member, and a part of the window support member is integrally formed with the main body support member.

[0093] Preferably, the bottom of the inner lining film is convex or flat, so as to ensure that the inner cavity size of the main body stent at the position where the inner lining film is provided is not too small, so as not to affect the hemodynamics in the aorta.

[0094] In this embodiment, the inner lining film and the main body film are also separately formed and then spliced and connected. In this way, it is more convenient to manufacture when the support unit is arranged on the inner lining film.

[0095] It can be understood that in order to take into account the opening shape of the folding part of the inner lining film, the opening of the folding part can be slightly concave inward. That is to say, the folding part is closer to the central axis of the stent graft than the bottom, and the support unit can be arranged only at the bottom of the inner lining film. Since the axial length of the folding part is significantly smaller than that of the bottom, even if the folding part is concave inward, it will not affect the hemodynamics of the blood flowing through the inner cavity of the main body stent.

[0096] Embodiment Six

[0097] The stent graft structure of this embodiment is generally the same as that of Embodiment Two, the difference being the reinforcement of the folding part. To better keep the folding part in a good opening shape, as Figure 27 shown, the stent graft of this embodiment includes a reinforcement 127, and the reinforcement 127 is arranged at the upper edge 1243 of the folding part. In this embodiment, the reinforcement 127 is a separate closed structure, which surrounds the opening of the folding part, supports the opening of the folding part, and reduces the deformation ability of the opening. The reinforcement 127 can be a corrugated structure similar to the main body support member, or a closed structure formed by enclosing a metal wire. As Figure 28 shown, when the reinforcement 127 is a closed structure, the part connected to the upper edge 1243 of the folding part is adapted to the arc of the main body stent, and the opposite part can be concave toward the central axis of the stent graft, or convex outward from the central axis of the stent graft or parallel to the central axis of the window and the stent graft.

[0098] It can be understood that in other embodiments, the reinforcing member may be a simple open structure, that is, the reinforcing member has two circumferential free ends or free edges. At this time, the projection of the reinforcing member on the cross-section perpendicular to the central axis of the covered stent may be a curved surface or a curve, or may also be a plane or a straight line segment. At this time, the reinforcing member may be provided on any section of the opening of the folding portion, that is, it may be provided on the upper surface of the folding portion where the upper edge is located (i.e., the upper folding unit), or may be provided on the lower surface of the folding portion opposite to the upper edge (i.e., the lower bottom unit), or span the upper surface and the lower surface.

[0099] It can also be understood that the reinforcing member can be formed separately, or integrally formed with the window support member, or integrally formed with the main body support member.

[0100] The above specific embodiments are only partial embodiments of the present invention and do not limit the present invention. This specification cannot list all embodiments of the inventive concept of the present invention exhaustively, and some features of the above different embodiments can be mutually replaced or combined. Those skilled in the art can also make simple replacements according to actual needs. The inventive concept of the present invention shall be subject to the scope of protection required.

Claims

1. A covered stent, comprising a main stent, wherein a window is formed on the surface of the main stent, characterized in that, The covered stent further includes an inner covered film, the edge of the inner covered film is connected to the main stent, the inner covered film includes a bottom portion and a folding portion, the folding portion is provided at the end of the bottom portion, the folding portion is disposed on the inner surface of the main stent, and is recessed toward the inner cavity of the main stent to form a receiving cavity; a through hole communicating with the inner cavity of the covered stent is further formed on the inner covered film, and the through hole communicates with the receiving cavity; the covered stent further includes a window support member, the window support member is disposed outside the inner covered film and protrudes outward from the surface of the inner covered film, the window support member includes a mesh structure having mesh holes, and the size of the mesh holes can be changed by an external force; the window support member includes a portion formed by cross-weaving of braided wires, and the intersection points of the braided wires are movable.

2. The covered stent according to claim 1, characterized in that, The window support member includes at least two support segments, the support segments are formed by cross-weaving of braided wires, and the at least two support segments are movably connected by hooking each other.

3. The covered stent according to claim 2, characterized in that, The portion of the support segment formed by cross-weaving of braided wires is located at the proximal end and / or the distal end of the window support member.

4. The covered stent according to claim 1, wherein In the mesh structure, the aperture of the mesh holes near the proximal end and / or the distal end of the window is larger than the aperture of the mesh holes in other parts.

5. The covered stent according to claim 1, wherein The main stent includes a main support member, a part of the main support member is located on the other side of the inner covered film opposite to the window support member, and the weaving density of the window support member is greater than the weaving density of the main support member opposite to the window support member in the main support member.

6. The covered stent according to claim 1, wherein The folding portion includes a proximal folding portion and a distal folding portion, the proximal folding portion and the distal folding portion are respectively disposed at both ends of the bottom portion, and at least one of the proximal folding portion and the distal folding portion is disposed on the inner surface of the main stent.

7. The covered stent according to claim 1, characterized in that, The proximal end and / or the distal end of the window support member extends beyond the edge of the window in the length direction of the covered stent.

8. The covered stent according to claim 1, characterized in that, A sinking section is formed on the surface of the window support member, and the cross-sectional area of the covered stent where the sinking section is located is smaller than the cross-sectional area of other parts of the covered stent away from the sinking section.

9. The covered stent according to any one of claims 1 to 8, characterized in that, The main stent includes a main covered film, a window is formed on the surface of the main covered film, and the inner covered film and the main covered film are separately formed and then spliced and connected.

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