Covered stent

Abstract

The invention provides a covered stent which comprises a stent body and a covering film, and the covering film at least partially covers the surface of the stent body. The stent body comprises a far-end section and a near-end section in the axial direction, the far-end section is provided with a far-end opening, the near-end section is provided with a near-end opening, the far-end opening is provided with at least one saddle part protruding towards the far end, and the saddle parts are arranged to conform to the sinus part of the aortic blood vessel, so that the extending stent part is provided to support the sinus blood vessel while the coronary artery opening is avoided; the covering area of the stent on a diseased region is increased; the covering film further comprises a free section, the free section exceeds the near-end opening, the free section is used for being sutured with an artificial blood vessel or an autologous blood vessel, a complete and closed aorta blood vessel is formed after suturing, leakage is avoided, and meanwhile suturing is easy.

Description

Technical Field

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

[0002] Aortic dissection is divided into type A (accounting for 70% of dissections) and type B (accounting for 30% of dissections). The mortality rate of type A is very high, with a 24-hour mortality rate reaching 25%, and basically every hour, the mortality rate increases by 1%. The situation of type B dissection is relatively better, with a mortality rate of about 10% within one week. Aortic dissection is a very dangerous disease, and its cure rate is also called the surgical success rate.

[0003] In the prior art, the clinical treatment method for type A dissection is basically artificial blood vessel replacement. David surgery is often used to solve the blood vessel replacement of the ascending aorta and corresponding treatments, and then an intraoperative stent is used in the aortic arch descending part to solve the distal problem. The proximal end of this intraoperative stent is sutured and fixed to the distal end of the artificial blood vessel to ensure that there is no endoleakage at the distal end of the artificial blood vessel. The distal end of the intraoperative stent uses the principle of endovascular intervention to treat the distal problem of the aortic arch. Currently, there is no unified method for dealing with the proximal end of the artificial blood vessel. To solve the problem of the proximal end of the artificial blood vessel now, most of the "products" used are felt pieces 10 and bovine pericardium; among them, the felt pieces 10 are cut on-site manually. The whole current situation is as Figure 1 shown in the shape. The felt piece 10 includes a straight section and a protruding section. After curling, that is, the head and tail of the straight section are connected end to end, as Figure 2 shown. The end faces of the straight sections of the felt pieces 10 overlap each other, and the protruding sections also have a certain curvature. As Figure 3 shown, the proximal blood vessel 20 of the ascending aorta with dissection disease includes a true lumen, a false lumen, and the left and right coronary arteries. As Figure 4 shown, the felt piece 10 is supported on the inner surface true lumen of the proximal blood vessel 20 of the ascending aorta, and then another felt piece 10 is cut, curled in the same way, and placed on the outer surface of the blood vessel false lumen, and then they are sutured together to the proximal blood vessel. At this time, the protruding sections of the felt pieces 10 cannot cover the openings of the left and right coronary arteries. Suture along the edges of the felt piece 10 and the felt piece 10 to flatten the false lumen of the blood vessel and complete the blood vessel reconstruction. The disadvantage of this method is that the felt piece 10 is relatively thick, making the suture laborious, with insufficient supporting force and time-consuming operation. The bovine pericardium is also cut on-site manually, with a shape similar to Figure 1 and is sutured to the blood vessel by the same method and then sutured to the artificial blood vessel. The thickness dimension of the bovine pericardium is relatively good, but long-term follow-up shows that it is prone to calcification, which will also affect the subsequent use performance. Summary of the Invention

[0004] Based on this, it is necessary to provide a new covered stent that, while not affecting the covered stent at the proximal left and right coronary artery openings, does not affect the subsequent size of the blood vessel, can be used in the blood vessel for a long time, and does not require on-site cutting to avoid abnormal situations such as infection.

[0005] A covered stent includes a stent body and a covering film, and at least a part of the covering film covers the surface of the stent body; the stent body includes a distal segment and a proximal segment connected to each other, and at least one saddle protruding towards the distal end is provided on the distal segment; the covering film includes a free segment, and the free end of the free segment extends beyond the proximal end of the proximal segment.

[0006] In one embodiment, the distal segment is connected to the proximal segment by hooking.

[0007] In one embodiment, the saddle includes a first high wave and a second high wave, and the protruding height of the first high wave is greater than that of the second high wave; there are at least two second high waves, and the first high wave is arranged between two adjacent second high waves.

[0008] In one embodiment, the first high wave includes two connected first wave bars, and the second high wave is pressed on the outside of the first wave bars.

[0009] In one embodiment, the saddle further includes a third high wave, and the third high wave includes two connected second wave bars, and the two second wave bars are respectively pressed on the outside of the two second high waves.

[0010] In one embodiment, the protruding height of the third high wave is greater than or equal to that of the second high wave and less than that of the first high wave.

[0011] In one embodiment, the covering film does not cover or partially covers the saddle.

[0012] In one embodiment, the free segment includes a connected portion and a folded portion, the connected portion is close to the proximal segment, the folded portion is far from the proximal segment, and the axial length of the folded portion is greater than that of the connected portion.

[0013] In one embodiment, the diameter of the free segment gradually expands from the connected portion towards the folded portion to form a trumpet-shaped covering film.

[0014] In one embodiment, the covering film is a single-layer covering film covering the outer surface of the stent body; or the covering film is a double-layer covering film covering the inner surface and the outer surface of the stent body respectively.

[0015] The beneficial effects of the present invention are as follows: Compared with the prior art, the present invention provides a covered stent, which includes a stent body and a covering film, and the covering film at least partially covers the surface of the stent body; the stent body includes a distal section and a proximal section along the axial direction, the distal section is provided with a distal opening, the proximal section is provided with a proximal opening, and the distal opening is at least provided with a saddle portion protruding towards the distal end. By providing the saddle portion, it conforms to the structure of the sinus part of the aortic blood vessel, provides an extended stent part to support the sinus blood vessel while avoiding the coronary ostium, fits the blood vessel, and increases the coverage area of the stent on the diseased part; wherein the covering film further includes a free section, and the free section extends beyond the proximal opening and is used for suturing with an artificial blood vessel or an autologous blood vessel to form a complete and closed aortic blood vessel, avoiding leakage and being easy to suture. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. is a schematic structural view of a felt sheet in the prior art.

[0017] Figure 2 FIG. is a schematic structural view of the felt sheet after being curled in the prior art.

[0018] Figure 3 FIG. is a schematic view of the proximal blood vessel of the ascending aorta of a patient with dissection disease.

[0019] Figure 4 FIG. is a schematic structural view of supporting a felt sheet to the proximal blood vessel of the ascending aorta of a patient with dissection disease in the prior art.

[0020] Figure 5 FIG. is a schematic structural view of the covered stent in Embodiment 1 of the present invention.

[0021] Figure 6 FIG. is a schematic sectional view of the covered stent of the present invention.

[0022] Figure 7 FIG. is a schematic sectional view of the covered stent in Embodiment 2 of the present invention.

[0023] Figure 8 For the present invention Figure 5 Partial enlarged view of position A.

[0024] Figure 9 FIG. is a partial left view of the saddle portion in Embodiment 2 of the present invention.

[0025] Figure 10 FIG. is a schematic view of the opening structure of the hollowed-out portion in Embodiment 3 of the present invention.

[0026] Figure 11 FIG. is a schematic view of the structure of the saddle portion without a covering film in Embodiment 3 of the present invention.

[0027] Figure 12 FIG. is a schematic view of the structure of the free section being a trumpet-shaped covering film in Embodiment 4 of the present invention.

[0028] Figure 13 Schematic structural diagram of the covered stent of the present invention when it is provided with a saddle part.

[0029] Figure 14 Schematic structural diagram of the covered stent of the present invention when it is provided with two saddle parts.

[0030] Figure 15 Schematic diagram of the wave angle of the first high wave in the present invention.

[0031] Figure 16 Schematic connection diagram of the covered stent of the present invention and the aortic blood vessel. Detailed implementation manners

[0032] To better understand the concept of the present invention, the following specifically describes the implementation manners 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.

[0033] For ease of description, spatially relative relationship terms may be used in the text to describe the relationship of one element or feature shown in the figure relative to another element or feature. These relative relationship terms such as "inner", "outer", "inner side", "outer side", "below", "beneath", "above", "upper" etc. are intended to include different orientations of the device in use or operation other than the orientation depicted in the figures. For example, if the device in the figure is flipped, then an element described as "below" or "beneath" other elements or features will then be oriented as "above" or "upper" other elements or features. Thus, the exemplary term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatially relative relationship descriptors used in the text are interpreted accordingly.

[0034] Although terms such as first, second, third etc. may be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply an order or sequence when used in the text. Thus, the first element, component, region, layer or section discussed below may be referred to as the second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

[0035] To more clearly describe the structure of the present application, the terms "proximal end" and "distal end" are defined herein as commonly used terms in the field of interventional medicine. Specifically, the "distal end" refers to the end of the aortic blood vessel close to the heart, and the "proximal end" refers to the end of the aortic blood vessel far from the heart. For example, during the stent implantation process, the end inserted into the human body is the distal end, and the end held or operated by the operator is the proximal end; the "axial direction" refers to its length direction, and the "radial direction" refers to the direction perpendicular to the "axial direction".

[0036] Embodiment 1:

[0037] Please refer to Figure 5 , in this embodiment, a covered stent 100 is provided, which includes a stent body 2 with a tubular structure and a film 1 with a tubular structure, wherein the film 1 at least partially covers the surface of the stent body 2; in this embodiment, the stent body 2 is woven and formed by braided wires in the form of M-shaped waves, Z-shaped waves or N-shaped waves. The stent body 2 includes a distal section 22 and a proximal section 23 along the axial direction. The distal section 22 is provided with a distal opening 221, and the proximal section 23 is provided with a proximal opening 231. The distal opening 221 and the proximal opening 231 are for the passage of blood. The distal opening 221 is at least provided with a saddle 21 protruding towards the distal end. The saddle 21 includes a protrusion formed by connecting two inclined wave rods at the top; the stent body 2 is used to support the distal blood vessel of the ascending aorta with dissection disease, and the stent body 2 is placed on the inner surface true lumen of the distal blood vessel of the ascending aorta, so as to ensure the space of the inner surface true lumen and avoid the compression of the false lumen on the true lumen resulting in damage to the true lumen space; the purpose of setting the saddle 21 is to conform to the structure of the sinus part of the aortic blood vessel, provide a supporting extension of the stent part to the sinus blood vessel while avoiding the coronary ostium, fit the blood vessel, and increase the coverage area of the stent on the diseased part; wherein in addition to partially covering the surface of the stent body 2, the film 1 further includes a free section 11. The free section 11 does not cover the stent body 2, and the free end of the free section 11 extends beyond the proximal opening 231. The free section 11 is used for suturing with artificial blood vessels and / or autologous blood vessels. After suturing, a complete and closed aortic blood vessel is formed. At the same time, the setting of the free section 11 can ensure that when suturing with the blood vessel, a relatively soft suturing position is provided, avoiding damage to the blood vessel; both the distal section 22 and the proximal section 23 are grid structures woven by braided wires, and the distal section 22 and the proximal section 23 are connected together by hooking to form a complete lumen of the stent body 2; the woven stent body 2 can provide sufficient radial support force while also having a certain flexibility. There are movable gaps between the woven grids, which can provide a certain amount of deformation range when subjected to force impact, thus playing a buffering role.

[0038] Among them, the distal segment 22 and the proximal segment 23 are connected by hooking, so that there is a connection gap between the distal segment 22 and the proximal segment 23 at the hooking connection position, so as to have a certain buffering effect when the stent body 2 is stressed and resist stent displacement in the axial direction; it can be understood that the coronary ostium is located in the ascending aorta segment of the aortic blood vessel, close to the heart, and the blood vessel pulsation at this position is relatively strong. When the stent is long-term set at this position, displacement problems may occur due to blood vessel pulsation. The stent body 2 is set as multiple segments and connected by hooking, so that when the blood vessel pulsates, a certain amount of relative displacement can occur between different segments of the stent body 2 at the hooking position. Coupled with the flexibility of the braided stent itself, the covered stent 100 can resist and buffer the pulsation from the blood vessel through the subtle relative movement between its own braided wires in the axial direction and the axial direction, thereby reducing or even avoiding the displacement of the covered stent 100 in the blood vessel and ensuring the long-term and stable effectiveness of the covered stent 100.

[0039] Please refer to Figures 6 - 8 , in this embodiment, the proximal segment 23 and the distal segment 22 of the stent body 2 are continuously provided with a waveform structure at the positions of the proximal opening 231 and the distal opening 221. The wave heights of the waveform structures are equal. The saddle part 21 includes a first high wave 211 and a second high wave 212. The wave heights of the first high wave 211 and the second high wave 212 in the axial direction are both greater than those of the continuous waveform structure. Further, the convex height of the first high wave 211 is greater than that of the second high wave 212, forming the highest vertex of the saddle part 21. At least two second high waves 212 are provided and arranged adjacent to each other. The first high wave 211 is arranged between two adjacent second high waves 212; with such a setting, a gradually changing structure with a slow convexity is formed on both sides of the convex part of the saddle part 21. The second wave height is located at the waist position of the saddle part 21, and the first wave height is located at the top position of the saddle part 21. The structure with two-layer wave height convexity can, firstly, increase the convex height of the saddle part 21, so as to achieve a larger coverage range of the stent body 2 while not blocking the coronary ostium; secondly, it can make the saddle part 21 have better supportability. Compared with a single waveform directly protruding to form the saddle part 21, the two second high waves 212 at the waist can provide support force for the first high wave 211 at the top, thereby enhancing the overall support force of the saddle part 21; in this embodiment, by setting two second high waves 212 and arranging the first high wave 211 between the two second high waves 212 to form the saddle part 21, however, the present application does not limit that only two second high waves 212 are provided. There can be three, four or more second high waves 212 arranged side by side, nor is it limited to two-layer high waves to form the saddle part 21. On the premise of not blocking the coronary ostium, three layers, four layers or more can also be set, and it can be reasonably set according to the density of the stent mesh and the size of the waveform.

[0040] Please refer to Figure 13, in this embodiment, a single braided wire is braided to form the proximal segment 23 of the stent body. The head end and the tail end of the braided wire are both wound around the wave rods of the grid structure for support. The distal segment 22 is braided at the distal end of the proximal segment 23 by a single braided wire, and the distal segment 22 is hooked to the proximal segment 23. The head end and the tail end of the braided wire are both wound around the wave rods of the grid structure for support, and at the same time, the support force of the wound wave rods can be improved. Please refer to Figure 7 and 8 , preferably, the head end and the tail end of the braided wire are both wound around the wave rods extending into the distal segment 22 and the proximal segment 23 when the first high wave 211 and the second high wave 212 are formed. Such winding can make the bottom of the first high wave 211 and the second high wave 212 have better support, so that the support of the saddle 21 is more firm. When braiding the distal segment 22, the second high wave 212 is braided and formed at any position of the distal segment 22. After braiding, the first high wave 211 is braided between two adjacent second high waves 212, and the two first wave rods 2111 connected to the first high wave 211 penetrate into the mesh hole where the second high wave 212 is located from the outer side of the stent body 2, and penetrate out from the inner side and abut against the wave peak B or the wave rod of the second high wave 212, so that the wave peak or the wave rod of the second high wave 212 always presses on the outside of the first wave rod 2111. Such a setting can prevent the first high wave 211 from tilting or expanding outward from the stent body 2, and then prevent damage to the blood vessel wall when entering the blood vessel.

[0041] Please refer to Figure 15 , in this embodiment, the wave angles of the first high wave 211 and the second high wave 212 are β, where 30° ≤ β ≤ 60°. An angle design greater than 60° will make the width of the saddle 21 too large, which will cause the saddle 21 to block the coronary artery after being implanted into the blood vessel, and it is not convenient to set multiple saddles 21; while an angle design less than 30° will cause the top of the saddle 21 to be too sharp, which is easy to pierce the film 1 or even damage the blood vessel. Preferably, please refer to Figure 6 , at the top of the saddle 21, that is, the height difference between the protrusion of the waveform structure of the first high wave 211 relative to the distal segment 22 is △H, where 5mm ≤ △H ≤ 20mm. The height setting not greater than 20mm can prevent the saddle 21 from having too high a protrusion height, and too high a protrusion height is easy to pierce into the aortic sinus or the valve, causing blood vessel damage; at the same time, the height setting not less than 5mm can also make the saddle 21 press and extend to the blood vessel dissection in the sinus. A protrusion height less than 5mm will result in too low a height and thus cannot press on the blood vessel dissection located in the sinus.

[0042] Please refer to Figures 5 - 6, in this embodiment, the length of the free section 11 of the film covering 1 extending proximally satisfies that after the proximal end of the free section 11 is turned outward and extends distally and is sutured to the blood vessel supported by the stent body 2, the free section 11 still includes a part that overlaps and does not cover the stent body 2, and this part is used for suturing and sealing with the artificial blood vessel or the blood vessel.

[0043] In another embodiment, please refer to Figures 13 - 14 , the saddle part 21 can be provided with not only one, but two or even more. When there are two, it includes a first saddle part 2101 and a second saddle part 2102. The first saddle part 2101 and the second saddle part 2101 can be arranged symmetrically along the circumferential direction and need to avoid the coronary blood vessels.

[0044] Embodiment Two:

[0045] Please refer to Figures 7 - 9 , in this embodiment, the structure of the stent body 2 and the structure of the film covering 1 are substantially the same as those in Embodiment One. The difference is that: the saddle part 21 is further provided with a third high wave 213. The third high wave 213 is a transition wave or a support wave. The third high wave 213 includes two connected second wave rods 2131. The two second wave rods 2131 are respectively pressed on the outer sides of the two second high waves 212, so that the third high wave 213 is radially arranged outside the second high wave 212 and the first high wave 211, providing a pressing effect for the first high wave 211 and the second high wave 212 in the radial direction, enhancing the radial force while avoiding warping and protruding outward to stab the blood vessel; please further refer to Figure 13 , wherein, the third high wave 213 can be formed by a single braided wire winding around the wave rod of the grid structure of the proximal section 23 to form a reinforcing rib 2132, then extending to the saddle part 21 to form a waveform, and then winding back to the proximal section 23. In this way, the third high wave 213 can obtain stronger support by winding around the wave rod of the grid structure of the proximal section 23 to form a reinforcing rib 2132, avoiding eversion due to insufficient support force and losing the support function; in other embodiments, it can also be directly woven at the saddle part 21 by the braided wire forming the stent body 2.

[0046] Among them, as a preferred solution, please refer to Figure 9 , the convex height of the third high wave 213 is greater than or equal to the convex height of the second high wave 212 and less than the convex height of the first high wave 211; with such a setting, the third high wave 213 is located in the gap between the first high wave 211 and the second high wave 212 at the saddle part 21, providing further support force for the saddle part 21, thereby further improving the wall attachment and stability of the saddle part 21 when the stent body 2 extends deep into the aortic blood vessel, stably pressing the diseased dissection to prevent secondary reverse tearing; avoiding the stent from being unstable or displaced due to the impact of blood flow in the blood vessel.

[0047] In another embodiment, not shown in the figures, in order to enable the third highest wave 213 to have better pressing performance, the third highest wave 213 is at least bent towards the inner cavity of the membrane-covered stent 100 at the position where it presses on the second highest wave 212. In this way, a tendency and force for the third highest wave 213 to press towards the inner cavity of the membrane-covered stent 100 can be generated, so that the third highest wave 213 can still maintain the pressing effect on the second highest wave 212 even when subjected to an outward force; preferably, the bending angle can be 5° to 10°; in this way, the third highest wave 213 is provided with a bending structure of at least 5° at the position where it presses on the second highest wave 212, which can enable the third highest wave 213 to further enhance the pressing effect in addition to the pressing effect provided by its own elasticity. By controlling the bending angle within 10°, it can be ensured that the wave crest of the third highest wave 213 will not protrude too much from the plane where the membrane is located, causing the membrane to be punctured and the blood vessel to be injured.

[0048] Embodiment Three:

[0049] Please refer to Figures 10 - 12 , in this embodiment, the structure of the stent body 2 and the structure of the membrane 1 are substantially the same as those in Embodiment One and Embodiment Two. The difference is that: the membrane 1 of the membrane-covered stent 100 may not cover or partially cover the saddle part 21. It can be understood that the membrane 1 may include a hollow part 3 at the saddle part 21. Only a part of the saddle part 21 is provided with the membrane 1, and the part located in the hollow part 3 is not provided with the membrane 1. In this way, it can be achieved by opening holes in the membrane 1 of the hollow part 3 on the saddle part 21, or the hollow part 3 may not be provided with the membrane 1 at all, and the membrane-covered stent 100 is a bare stent at the saddle part 21; the saddle part 21 is the part that extends into the aortic sinus for support. Due to the pulsation of the blood vessel, the saddle part 21 may shift in position during long-term use in the blood vessel, or block the coronary ostium when placed inaccurately. The structure of opening through holes or not providing the membrane 1 enables the blood at the coronary ostium to still pass through the saddle part 21 even if the saddle part 21 blocks the coronary ostium, so that the stent will not completely block the blood flow at the coronary ostium during long-term use, ensuring that while the saddle part 21 provides support to press on the dissection, the patency of the coronary ostium is ensured; it can be understood that not providing the membrane 1 on the saddle part 21 means that the membrane 1 only covers the proximal segment 23 and the distal segment 22 of the stent body 2, and the membrane 1 below the saddle part 21 of the distal segment 22 is flush with the distal opening 221 and does not extend into the saddle part 21.

[0050] In another embodiment, not shown in the figure, the film 1 only covers the surface of the braided wires of the first high wave 211, the second high wave 212, and the third high wave 213 at the saddle portion 21, and does not cover the mesh holes formed thereby; in this way, the metal part of the stent body 2 can be hidden, and only the film 1 contacts the blood vessel surface, which can improve the flexibility of the braided wires at the saddle portion 21 to a certain extent and reduce the possibility of the rigidity of the metal itself piercing the blood vessel.

[0051] In this embodiment, the film 1 is a single-layer film covering the outer surface of the stent body 2. Laying the single-layer film on the outer surface of the stent body 2 can avoid excessive friction between the stent body 2 and the blood vessel and damage to the blood vessel; it can be understood that the single-layer film is connected to the stent body 2 by suture, and the single-layer film can be made of PET or ePTFE film, preferably PET film.

[0052] In another embodiment, please refer to Figure 6 , the film 1 is a double-layer film covering both the inner surface and the outer surface of the stent body 2 at the same time; it can be understood that the double-layer film is formed by an ePTFE film with a relatively thin thickness on the outer surface and the inner surface of the stent body 2 and is fixed on the stent body 2 by heat treatment or bonding; it can be understood that when using the double-layer film, the stent body 2 is completely accommodated between the two layers of films. The double-layer film can be a single-piece cylindrical film. After folding at the middle position, the distal end and the proximal end are aligned to form the total length of the film 1 of the covered stent 100. Then, the distal port of the stent body 2 and the raised shape of the saddle portion 21 are cut out at its position. The distal port of the stent body 2 is placed at the distal port position of the double-layer cylindrical film 1 and aligned, and then hot melting or bonding is performed to form the covered stent 100. In this way, the integrity of the film 1 can be ensured. Although it is a double-layer film, it is formed in a single piece, which simplifies the processing steps and avoids the risk of separation and leakage of the double-layer film during use.

[0053] Among them, regardless of whether the film 1 is a single-layer film or a double-layer film, its formed thickness is between 0.4 mm and 0.7 mm.

[0054] Embodiment 4:

[0055] Please refer to Figure 6 and Figure 12, in this embodiment, the structure of the stent body 2 and the structure of the membrane 1 are substantially the same as those in the first to third embodiments. The difference lies in that: the free section 11 of the membrane 1 axially includes a connecting section 112 and a folding section 111, where the connecting section 112 is close to the proximal section 23 of the stent body 2, the folding section 111 is far from the proximal section 23 of the stent body 2, and the folding section 111 and the connecting section 112 are continuously arranged; it can be understood that the axial length of the folding section 111 is greater than the axial length of the connecting section 112; there is a folding position between the folding section 111 and the connecting section 112 for the free section 11 of the membrane 1 to be folded outwards; after the folding section 111 is folded, it is pulled towards the stent body 2 until the folding position coincides with the folding position. At this time, the proximal part of the folding section 111 covers the blood vessel outside the stent body 2 for suturing and connecting with the blood vessel supported by the stent body 2; after connection, there is a suture part between the folding position and the stent body 2. The suture part has a double-layer membrane 1 structure and is sutured with the artificial blood vessel or the remaining ascending aorta blood vessel segment through the suture part to form a complete aortic blood vessel.

[0056] Preferably, please refer to Figure 6 , the free section 11 is provided with an indication mark 12 at the folding position. The indication mark 12 is used to provide an indication function for the doctor during the operation; the indication mark 12 satisfies that when the folding section 111 is folded to the position of the indication mark 12, the proximal part of the folding section 111 covers the proximal section 23 of the stent body 2; when the doctor folds the free section 11 outwards, it can be directly folded to the position of the indication mark 12 and stop. At this time, there is a partially overlapping position between the folding section 111 and the blood vessel, and suturing and fixing can be carried out; the indication mark 12 can be an indication line drawn on the inner wall of the cylindrical membrane 1 of the free section 11. The indication line is exposed when the free section 11 is folded to its position, and the doctor can directly visually identify it; it can be understood that this indication line can also be used as the suture position identification for the doctor, and the doctor can directly anastomose and suture the ascending aorta blood vessel or the artificial blood vessel directly at the position of the indication line.

[0057] In this embodiment, the axial length of the connecting section 112 is preferably between 10 mm and 20 mm. This length can meet the requirement that it is convenient for the doctor to suture and connect the ascending aorta blood vessel or the artificial blood vessel with the connecting section 112; a connecting length less than 10 mm will result in insufficient suture length for the doctor during suturing, and a length greater than 20 mm will form an overly long connecting section 112, resulting in the swing of the blood vessel and the membrane stent 100 at the connecting section 112 position after connection, affecting the long-term effect.

[0058] In another embodiment, the diameter of the free segment 11 gradually expands from the proximal opening 231 in the extending direction, forming a flared film covering 1101; the expansion structure of the flared film covering 1101 enables the free segment 11 to have better folding characteristics during the step of folding the film covering, and at the same time, the flared opening is also more conducive to the entry and suturing of the ascending aorta or the artificial blood vessel.

[0059] The following briefly introduces the implantation of the covered stent 100 of the present application during the operation with reference to the attached Figure 16 First, under surgical conditions, block the ascending aorta, perform extracorporeal circulation, and directly release the covered stent 100 into the blood vessel near the coronary artery under direct vision, and ensure that the saddle part 21 of the covered stent 100 does not interfere with the opening of the coronary artery, that is, the coronary artery orifice, and align the proximal side of the stent body with the proximal edge of the blood vessel 30 near the coronary artery;

[0060] First, under surgical conditions, block the ascending aorta, perform extracorporeal circulation, and directly release the covered stent 100 into the blood vessel near the coronary artery under direct vision, and ensure that the saddle part 21 of the covered stent 100 does not interfere with the opening of the coronary artery, that is, the coronary artery orifice, and align the proximal side of the stent body with the proximal edge of the blood vessel 30 near the coronary artery;

[0061] Then, perform the first suturing operation on the covered stent 100 and the blood vessel 30 near the coronary artery to fix the covered stent 100;

[0062] Next, curl the film covering 1 of the free segment 11 to the indicated line position so that the film covering 1 of the free segment 11 partially covers the outer surface of the blood vessel 30 near the coronary artery, and then perform the second suturing operation on the folded part 111 of the film covering 1 of the free segment 11 and the blood vessel 30 near the coronary artery to connect the covered stent 100 and the blood vessel 30 near the coronary artery, ensuring strength and reducing leakage.

[0063] Secondly, perform the third suturing operation on the proximal end of the film covering 1 and the connecting part 112 of the free segment 11 after the first suturing and the ascending aorta blood vessel 20 (or the artificial blood vessel 20). The length of the film covering 1 protruding after folding is about 1-2 cm, and the suture is kept with an appropriate width. The third suturing operation connects the covered stent 100 and the proximal aorta blood vessel 20 (or the artificial blood vessel 20), also ensuring strength and reducing leakage, thus forming an integral blood vessel; in the distal direction: the covered stent 100 is connected to the blood vessel 30 near the coronary artery; in the proximal direction: the covered stent 100 is connected to the ascending aorta blood vessel 20 (or the artificial blood vessel 20), and then start the in-vivo circulation to end the operation.

[0064] The above specific embodiments are only partial embodiments of the present invention and do not limit the present invention. This specification cannot list all the 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 is subject to the scope of protection required.

Claims

1. A covered stent, characterized in that, It includes a stent body and a membrane, and the membrane at least partially covers the surface of the stent body; the stent body includes a distal segment and a proximal segment connected to each other, and at least one saddle protruding distally is provided on the distal segment; the membrane includes a free segment, and the free end of the free segment extends beyond the proximal end of the proximal segment.

2. The covered stent according to claim 1, characterized in that, The distal segment is connected to the proximal segment by hooking.

3. The covered stent according to claim 2, wherein The saddle includes a first high wave and a second high wave, and the protruding height of the first high wave is greater than that of the second high wave; there are at least two second high waves, and the first high wave is provided between two adjacent second high waves.

4. The covered stent according to claim 3, wherein, The first high wave includes two connected first wave rods, and the second high wave is pressed on the outside of the first wave rod.

5. The covered stent according to claim 4, wherein The saddle further includes a third high wave, and the third high wave includes two connected second wave rods, and the two second wave rods are respectively pressed on the outside of the two second high waves.

6. The covered stent according to claim 5, characterized in that, The protruding height of the third high wave is greater than or equal to that of the second high wave and less than that of the first high wave.

7. The covered stent according to claim 1, characterized in that, The membrane does not cover or partially covers the saddle.

8. The covered stent according to claim 1, characterized in that, The free segment includes a connected connecting portion and a folding portion, the connecting portion is close to the proximal segment, the folding portion is far from the proximal segment, and the axial length of the folding portion is greater than the axial length of the connecting portion.

9. The covered stent according to claim 8, characterized in that, The diameter of the free segment gradually expands from the connecting portion towards the folding portion to form a trumpet-shaped membrane.

10. The covered stent according to claim 1, wherein, The membrane is a single-layer membrane covering the outer surface of the stent body; or the membrane is a double-layer membrane respectively covering the inner surface and the outer surface of the stent body.

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