Covered stent

Abstract

The invention provides a covered stent. The covered stent comprises a main stent body and a binding assembly. The body support sequentially comprises a near-end section, a middle section and a far-end section in the axial direction, the side face of the middle section sinks towards an inner cavity of the body support to form a groove, the middle section comprises at least one middle wave ring, and the middle wave ring comprises a plurality of first short waves and at least one first high wave. Wherein at least one first high wave crosses two sides of one edge of the groove in the width direction, the constraint assembly is arranged on the main body support and has a constraint state and a release state, when the constraint assembly is in the constraint state, the constraint assembly constrains at least one area of the middle section in the radial direction, and when the constraint assembly is in the release state, the constraint assembly relieves constraint on the middle section. According to the covered stent provided by the invention, the risk of blocking a branch opening can be reduced, and the shape of the edge of the groove can be better maintained.

Description

Technical Field

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

[0002] Aortic aneurysms and aortic dissections are currently diseases that seriously endanger human life safety. If not actively treated, the aortic aneurysm and dissection will continue to grow 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 aneurysms and aortic dissections is also increasing significantly.

[0003] Traditional open surgeries for treating aortic aneurysms and aortic dissections have the disadvantages of large trauma, high mortality, long operation time, high incidence of postoperative complications, and high operation difficulty. Endovascular treatment surgeries, on the other hand, have the characteristics of small trauma, few postoperative complications, short operation time, and low operation difficulty, and have gradually become the main method for treating aortic aneurysms and aortic dissections currently. In endovascular treatment surgeries, a stent is implanted into the aorta through a delivery device, isolating the vascular lesion outside the stent and restricting blood flow to pass through the inside of the stent, thereby achieving the purpose of protecting the blood vessel.

[0004] When an aneurysm or arterial dissection is located at a position on the aorta close to the branch vessel, the implanted stent may block the opening of the branch vessel, thereby causing blood flow in the branch vessel to be blocked. One of the current methods to solve this problem is to provide a groove on the stent, and the inner wall of the groove is provided with a branch opening communicating with the inner cavity of the stent. The groove corresponds to the branch vessel to ensure that blood in the aorta enters the branch vessel through the groove. However, after the stent is implanted into the blood vessel, if the blood vessel lumen is relatively narrow, it will squeeze the space of the groove, causing an obstacle for the guide wire or the external branch stent to enter the branch opening. Summary of the Invention

[0005] In view of the above-mentioned deficiencies, the present invention provides a covered stent.

[0006] An embodiment of the present invention provides a covered stent, including: a main body stent, the main body stent sequentially includes a proximal section, a middle section, and a distal section along the axis. The side surface of the middle section is recessed towards the inner cavity direction of the main body stent to form a groove. The middle section includes at least one middle wave ring, and the middle wave ring includes a plurality of first short waves and at least one first high wave, wherein at least one of the first high waves straddles both sides of the edge of one width direction of the groove;

[0007] A constraint assembly is provided on the main body stent, having a constrained state and a released state. When in the constrained state, the constraint assembly radially constrains at least one area of the middle section. When in the released state, the constraint assembly releases the constraint on the middle section.

[0008] An embodiment of the present invention provides a covered stent, comprising:

[0009] A main body stent, provided with a groove, and the bottom of the groove includes a bottom film;

[0010] A support structure, comprising a bottom support member for supporting the bottom film;

[0011] Wherein, the bottom support member includes two support portions arranged at intervals in the radial direction, the bottom film includes a blank bottom film section, and the bottom film section is located between the two support portions in the radial direction; the two support portions can move relative to each other so that the bottom film section can be deformed.

[0012] An embodiment of the present invention also provides a covered stent, comprising:

[0013] A main body stent, provided with a groove;

[0014] A limiting structure, comprising a limiting member and a constraining member, and the limiting member is detachably connected to the constraining member; when the covered stent is in the first state, the limiting member can be used to limit a target section of a sheath core in the radial direction under the constraint of the constraining member, the target section is an axial section of the sheath core, and the target section is located in the axial region between the proximal end and the distal end of the groove in the first state; when the covered stent is in the second state, the constraining member can be disengaged from the limiting member so that the limiting member releases the restriction on the target section.

[0015] An embodiment of the present invention also provides a covered stent, comprising:

[0016] A main body stent, provided with a groove;

[0017] Two inner branch stents, the two inner branch stents are arranged side by side in the radial direction inside the main body stent, the inner branch stents are provided with branch openings facing the groove, and the branch openings are communicated with the groove;

[0018] A limiting channel, formed between the two inner branch stents, for limiting the sheath core in the radial direction.

[0019] The coated stent provided by the embodiment of the present invention has a restraining component. During the implantation process, after the coated stent is released from the sheath, the restraining component remains in a restrained state, maintaining radial restraint on at least one area of ​​the middle section, so that a gap is formed between the blood vessel wall and at least part of the middle section, which can reduce the risk of blockage of the branch opening and allow the guide wire and the outer branch stent to smoothly enter the branch opening through the gap. In addition, since at least one first high wave spans both sides of one of the width-direction edges of the groove, it is beneficial to better maintain the shape of the edge in the width direction of the groove and both sides of the edge, and the both sides of the edge in the width direction of the groove are more uniform when subjected to force, and wrinkles are not easily formed after implantation to cause thrombosis.

[0020] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and are not restrictive of the disclosure of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of the implantation state of the covered stent provided by one embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of a stent graft provided by an embodiment of the present invention;

[0024] Figure 3 is a partial structural schematic diagram of a stent graft provided by an embodiment of the present invention;

[0025] Figure 4 is a partial structural schematic diagram of a stent graft provided by an embodiment of the present invention;

[0026] Figure 5 is a schematic structural diagram of a stent graft provided by an embodiment of the present invention;

[0027] Figure 6 is a partial structural schematic diagram of a stent graft provided by an embodiment of the present invention;

[0028] Figure 7 is a schematic structural diagram of a stent graft provided by an embodiment of the present invention;

[0029] Figure 8 is a schematic structural diagram of a stent graft provided by an embodiment of the present invention, wherein the sheath core is penetrated by the stent graft;

[0030] Figure 9 FIG. 1 is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention, which shows a bottom film and a support structure;

[0031] Figure 10 FIG. 2 is a cross-sectional schematic diagram of a covered stent provided by an embodiment of the present invention, which shows a limiting groove;

[0032] Figure 11 FIG. 3 is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention, which shows a bottom film and a support structure;

[0033] FIG. 12(A) is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0034] FIG. 12(B) is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0035] Figure 13 FIG. 13 is a partial structural schematic diagram of a support structure provided by an embodiment of the present invention;

[0036] Figure 14 FIG. 14 is a partial structural schematic diagram of a bottom support provided by an embodiment of the present invention;

[0037] Figure 15 FIG. 15 is a structural schematic diagram of a covered stent provided by an embodiment of the present invention, in which a sheath core penetrates through the covered stent;

[0038] Figure 16 is Figure 15 a partial structural schematic diagram in;

[0039] FIG. 17(A) is Figure 15 a partial structural schematic diagram in;

[0040] FIG. 17(B) is a connection schematic diagram of a limiting member and an outer sheath tube of a conveyor provided by an embodiment of the present invention;

[0041] Figure 18 FIG. 18 is a structural schematic diagram of a limiting member provided by an embodiment of the present invention;

[0042] Figure 19 FIG. 19 is a structural schematic diagram of a first limiting portion provided by an embodiment of the present invention;

[0043] FIG. 20(A) is a structural schematic diagram of a second limiting portion provided by an embodiment of the present invention;

[0044] FIG. 20(B) is a structural schematic diagram of a second limiting portion provided by an embodiment of the present invention;

[0045] Figure 21 FIG. 21 is a structural schematic diagram of a covered stent provided by an embodiment of the present invention, in which a sheath core penetrates through the covered stent;

[0046] Figure 22 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0047] Figure 23 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0048] Figure 24 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0049] Figure 25 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0050] Figure 26 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0051] Figure 27 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0052] Figure 28 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention, which shows a limiting channel and an end support;

[0053] Figure 29 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention, which shows a limiting channel and an end support;

[0054] Figure 30 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0055] Figure 31 It is a partial side view of the structure of a covered stent provided by an embodiment of the present invention;

[0056] Figure 32 It is a schematic diagram of the planar expansion of an intermediate corrugated ring provided by an embodiment of the present invention;

[0057] Figure 33 It is a schematic diagram of the planar expansion of a main corrugated ring provided by an embodiment of the present invention;

[0058] Figure 34 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention;

[0059] Figure 35 It is a schematic diagram of the planar expansion of a non-closed corrugated ring provided by an embodiment of the present invention;

[0060] Figure 36 It is a partial structural schematic diagram of a covered stent provided by an embodiment of the present invention when the restraint assembly is in a restrained state;

[0061] Figure 37 It is a schematic diagram of the radial limiting sheath core of the easy-to-collect part provided by an embodiment of the present invention;

[0062] Figure 38 It is a plane unfolding schematic diagram of the closed wave loop provided by an embodiment of the present invention. Detailed implementation manners

[0063] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0064] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0065] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0066] It should be further understood that the term " / and" as used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0067] Next, some embodiments of the present invention will be described in detail in conjunction with the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0068] For ease of description, 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 where blood flows out, and the "proximal end" refers to the end where blood flows in. For example, after a stent is implanted into a lumen, blood flows from the proximal end of the stent towards the distal end; the "axial direction" refers to its length direction, or the direction in which the interventional device is advanced and withdrawn; the "radial direction" refers to the direction perpendicular to the "axial direction".

[0069] Taking a blood vessel as an example to illustrate the lumen, the blood vessel may include at least one of the following: aortic arch, thoracic aorta, abdominal aorta, etc. Those of ordinary skill in the art should understand that using a blood vessel for illustration is only for example and not a limitation to the present invention. The solution of the present invention is applicable to various human lumens or other biological lumens. Human lumens may include, for example, digestive tract lumens or blood vessels, etc. All improvements and modifications based on the teachings of the present invention are within the protection scope of the present invention.

[0070] The "wave loop" in the embodiments of the present invention includes multiple waves, and the "waveform unit" includes at least one wave. Among them, the "wave loop" (which can also be called a waveform ring structure) is a closed or non-closed waveform ring structure. Both the wave loop and the waveform unit can be provided on the inner wall and / or outer wall of the membrane of the covered stent. The wave loop or the waveform unit can be connected to the membrane by at least one of the following connection methods: suture, bonding, hot melting, etc. The "wave loop" and the "waveform unit" are made by weaving or cutting a metal elastic material, a polymer material or other biocompatible elastic materials. The metal elastic material includes known materials implanted in medical devices or combinations of various biocompatible materials, such as alloys of two or more single metals among cobalt, chromium, nickel, titanium, magnesium, iron, and 316L stainless steel, nickel-titanium-tantalum alloy, etc., or other biocompatible metal elastic materials. The polymer material includes biocompatible materials such as polylactic acid. Both the "wave loop" and the "waveform unit" have the ability of radial expansion, can achieve radial contraction under external force, and self-expand or expand mechanically (for example, expand by balloon dilation) after the external force is withdrawn to restore to the initial shape and maintain the initial shape. Thus, after being implanted into the lumen, it can closely adhere to the inner wall of the lumen through its radial supporting force. The waveform of the waves in the "wave loop" and the "waveform unit" is not limited, including Z-shaped waves, M-shaped waves, V-shaped waves, sine waves, etc. Both the "wave loop" and the "waveform unit" include wave peaks, wave valleys, and wave rods connecting adjacent wave peaks and wave valleys. Among them, one vertex (wave peak or wave valley) and the two wave rods connected to the vertex form a wave.

[0071] The "support structure" in an embodiment of the present invention can be connected to the bottom film by at least one of the following connection methods: stitching, bonding, heat melting, etc. The support structure can be disposed on the inner wall and / or outer wall of the bottom film of the film stent. The support structure can include a corrugated unit and / or a mesh structure, etc. The support structure is woven or cut from a metal elastic material, a polymer material, or other biocompatible elastic materials. The metal elastic material includes known materials implanted in medical devices or combinations of various biocompatible materials, such as alloys of two or more single metals among cobalt, chromium, nickel, titanium, magnesium, iron, and 316L stainless steel, nickel-titanium-tantalum alloy, etc., or other biocompatible metal elastic materials. The polymer material includes biocompatible materials such as polylactic acid.

[0072] The "film" in an embodiment of the present invention can isolate liquid to a certain extent, and it can be made of at least one biocompatible polymer material such as polytetrafluoroethylene (abbreviated as PTFE), polyethylene terephthalate (abbreviated as PET), etc.

[0073] Please refer to Figure 1 , an embodiment of the present invention provides a film stent 100 for implanting into a target cavity. The above target cavity can be any cavity in a living body, and the present invention does not limit the type of the target cavity. For the convenience of understanding, the present invention takes the aortic arch 300 as an example of the target cavity for illustration. Referring to Figure 1 , three branch vessels 200 are connected to the aortic arch 300. The branch vessels 200 are connected to the large curvature side of the aortic arch 300. Blood flows from the aortic arch 300 to the branch vessels 200. An aneurysm 400 is formed on the small curvature side of the aortic arch 300 (only for illustration, in other embodiments, the aneurysm 400 may be distributed at other positions of the aortic arch 300). By implanting the film stent 100 into the aortic arch 300 to isolate the aneurysm 400, the blood flowing in the film stent 100 cannot contact the aneurysm 400, and finally the purpose of treating the aneurysm 400 is achieved. An outer branch stent 500 can also be implanted in the three branch vessels 200. The outer branch stent 500 can be connected to the film stent 100, and the blood in the film stent 100 enters the branch vessels 200 through the outer branch stent 500.

[0074] Please refer to Figure 1 and Figure 2, in some embodiments, the covered stent 100 is generally a hollow tubular structure with openings at both ends. The covered stent 100 includes a main stent 10. Exemplarily, the main stent 10 includes a main covering membrane 11 and a stent body 12. The stent body 12 can be disposed on the inner surface and / or outer surface of the main covering membrane 11. The main covering membrane 11 can completely cover the stent body 12 or partially cover the stent body 12. Exemplarily, the stent body 12 includes at least one support corrugated ring for supporting the main covering membrane 11.

[0075] Exemplarily, the main covering membrane 11 can be a single-layer structure or a multi-layer structure, which is not limited herein. The main covering membrane 11 can be made of at least one of the following materials: polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), other polymer materials with good biocompatibility, etc. The main covering membrane 11 can be fixed on the inner surface and / or outer surface of the stent body 12 by means of suture, adhesion, hot melting, etc., so as to play roles such as reconstructing a fluid channel and isolating a diseased area of a blood vessel.

[0076] Please refer to Figure 1 and Figure 2 , in some embodiments, the main stent 10 can be axially divided into a distal section 1, a proximal section 2, and an intermediate section 3. The intermediate section 3 is located between the proximal section 2 and the distal section 1. The proximal section 2 includes a tubular proximal stent 2a and a proximal main covering membrane 11a. The proximal main covering membrane 11a can be covered on the inner surface and / or outer surface of the proximal stent 2a by means of suture, adhesion, hot melting, etc. The proximal stent 2a includes a plurality of main corrugated rings 101 arranged at axial intervals. The distal section 1 includes a tubular distal stent 1a and a distal main covering membrane 11b. The distal stent 1a includes a plurality of main corrugated rings 101 arranged at axial intervals. The distal main covering membrane 11b can also be covered on the inner surface and / or outer surface of the distal stent 1a by means of suture, adhesion, hot melting, etc. The intermediate section 3 includes an intermediate main covering membrane 11c and an intermediate stent 3a. The intermediate stent 3a includes a plurality of arc-shaped corrugated units arranged at axial intervals. The intermediate main covering membrane 11c can be covered on the inner surface and / or outer surface of the intermediate stent 3a by means of suture, adhesion, hot melting, etc. The inner cavity formed by enclosing the intermediate main covering membrane 11c is communicated with the inner cavity formed by enclosing the proximal main covering membrane 11a and the inner cavity formed by enclosing the distal main covering membrane 11b.

[0077] Please also refer to Figure 2 and Figure 3, in some embodiments, the main body stent 10 is provided with a groove 5. Exemplarily, the main body stent 10 is recessed towards its inner cavity on the side of the middle section 3 to form the groove 5. The groove 5 includes a groove bottom 51 and a groove opening 52. Among them, the groove opening 52 and the groove bottom 51 are oppositely arranged in the radial direction of the covered stent 100, and the groove opening 52 faces the radial outside of the covered stent 100, while the groove bottom 51 is closer to the inner cavity of the main body stent 10 as a whole than the groove opening 52. In some embodiments, the edge of the groove 5 formed on the main body film 11 is substantially rectangular, that is, when the main body film 11 is unfolded along the generatrix not passing through the groove 5, the groove 5 is substantially rectangular. The groove 5 includes a first edge 531, a second edge 532, a third edge 533 and a fourth edge 534. Among them, the first edge 531 and the second edge 532 are oppositely arranged in the radial direction (or oppositely arranged in the width direction of the groove 5) and are consistent with the length extension direction of the covered stent 100. The third edge 533 and the fourth edge 534 are oppositely arranged in the axial direction and are closer to the end of the covered stent 100 than the first edge 531 and the second edge 532. It can be understood that in other embodiments, the groove 5 can also be other shapes, as long as the first edge 531 and the second edge 532 generally extend along the length extension direction of the covered stent 100. For example, they can form a certain angle with the length extension direction of the covered stent 100 (such as the groove 5 is trapezoidal), or the first edge 531 and the second edge 532 are arc-shaped (such as the groove 5 is similar to an ellipse). The present invention does not limit the specific shape of the groove 5. In other embodiments, the groove 5 can also be an annular recessed structure surrounding the main body stent 10. It can also be understood that the groove 5 is located between the proximal end and the distal end of the covered stent 100. The groove 5 can be closer to the proximal end of the covered stent 100, or closer to the distal end of the covered stent 100, or the distance from the proximal end of the covered stent 100 is equal to the distance from the distal end of the covered stent 100.

[0078] Please refer to Figure 2 and Figure 3, in some embodiments, the covered stent 100 is further provided with an inner branch stent 8, and the inner branch stent 8 includes a tubular branch covering 801. The number of the inner branch stents 8 can be designed according to actual needs, such as one, two, three or more. At least one inner branch stent 8 is disposed on one axial side of the groove 5. In some embodiments, a plurality of inner branch stents 8 are provided. The inner branch stents 8 are located in the inner cavity of the main stent 10 and are respectively disposed on the proximal side and the distal side of the groove 5. For example, the inner branch stent 8 is disposed in the main stent 10, the inner branch stent 8 is connected to the inner wall of the main stent 10, and the inner branch stent 8 extends along the length direction of the main stent 10. The inner cavity of the inner branch stent 8 communicates with the inner cavity of the main stent 10 and the groove 5. When an outer branch stent 500 needs to be implanted into the branch blood vessel 200, one end of the outer branch stent 500 can be sleeved with the inner branch stent 8, and the other end extends through the groove 5 to the corresponding branch blood vessel 200, so as to form a channel for blood to flow from the main stent 10 to the branch blood vessel 200. In this embodiment, branch support members can also be provided on the branch covering 801 of the inner branch stent 8 to better maintain the shape of the inner branch stent 8.

[0079] Please refer to Figure 2 , in some embodiments, a mesh cover 61 is further provided outside the groove 5. The two circumferential sides of the mesh cover 61 are respectively fixedly connected to the middle main body covering 11c by means of sewing, bonding, hot melting, etc., and at least a part of the mesh cover 61 forms a gap (or void, cavity, interval) with the bottom 51 of the groove 5 in the radial direction of the covered stent 100, and this gap can communicate with the inner cavity of the inner branch stent 8. Exemplarily, the mesh cover 61 is in an arc-shaped structure in the circumferential direction and is integrally woven into a mesh structure by knitting wires; the central angle corresponding to the projection of the mesh cover 61 on the radial plane is less than or equal to 120 degrees, so that the mesh cover 61 has good radial support force and ensures that there is enough space in the main stent 10 for blood flow to pass through. In other embodiments, the above-mentioned mesh cover 61 can be omitted.

[0080] Please refer to Figure 3 and Figure 4, exemplarily, the bottom of the groove 51 includes a bottom film 51a, through which the inner cavity of the main body stent 10 can be radially isolated from the groove 5. Exemplarily, the first edge 531 and the second edge 532 of the groove 5 are respectively connected to the two radial sides (also referred to as the two sides in the width direction, or the two transverse sides) of the bottom film 51a, and the third edge 533 and the fourth edge 534 of the groove 5 are respectively connected to the two axial ends of the bottom film 51a. Each inner branch stent 8 includes two branch openings, one of which is closer to the groove 5 than the other. The branch opening closer to the groove 5 is connected to the bottom of the groove 51. Among them, the branch opening closer to the groove 5 includes an upper edge and a lower edge, the upper edge of which is connected to the inner wall of the main body stent 10, and the lower edge of which can be sewn, bonded or integrally formed with the bottom film 51a.

[0081] Please refer to Figure 4 , exemplarily, two inner branch stents 8 are provided in the inner cavity of the proximal segment 2 of the main body stent 10, denoted as the first branch stent 81 and the second branch stent 82 respectively. The first branch stent 81 and the second branch stent 82 are arranged side by side in the radial direction on the proximal side of the groove 5. The first branch opening 811 is provided at the end of the first branch stent 81 closer to the groove 5 (i.e., the distal end of the first branch stent 81), and the second branch opening 821 is provided at the end of the second branch stent 82 closer to the groove 5 (i.e., the distal end of the second branch stent 82). Both the first branch opening 811 and the second branch opening 821 face the groove 5. Branch openings are also provided at the proximal ends of the first branch stent 81 and the second branch stent 82, and these branch openings all face the proximal end of the main body stent 10. One inner branch stent 8 is provided in the inner cavity of the distal segment 1 of the main body stent 10, denoted as the third branch stent 83. The third branch stent 83 is arranged on the distal side of the groove 5. The third branch opening 831 is provided at the end of the third branch stent 83 closer to the groove 5 (i.e., the proximal end of the third branch stent 83), and this third branch opening 831 faces the groove 5. A branch opening is also provided at the distal end of the third branch stent 83, and this branch opening faces the distal end of the main body stent 10.

[0082] Please refer to Figure 5, in some embodiments, the covered stent 100 includes a first branch stent 81 and a second branch stent 82. The first branch stent 81 is disposed within the main body stent 10 and communicates with the groove 5. The second branch stent 82 is connected to the main body stent 10. One end of the second branch stent 82 is fixedly connected to and communicates with the main body stent 10, and the other end is a free end and has a branch opening. The free end of the second branch stent 82 is disposed outside the main body stent 10 for implantation into the branch blood vessel 200 or connection to other stents. The length extension direction of the second branch stent 82 intersects the axial direction; both the second branch stent 82 and the first branch stent 81 communicate with the inner cavity of the main body stent 10. After the second branch stent 82 communicates with the corresponding branch blood vessel 200, the groove 5 of the covered stent 100 is aligned with the openings of other branch blood vessels 200, which can reduce the situation that it is difficult for the groove 5 to be aligned with the corresponding branch blood vessel 200 due to the deflection of the covered stent 100 after release; in addition, by disposing the free end of the second branch stent 82 outside the main body stent 10, the second branch stent 82 can be implanted into the branch blood vessel 200 without occupying the space of the inner cavity of the main body stent 10, thereby reducing the occupation of the inner cavity of the main body stent 10 by the branch stent and increasing the blood flow in the inner cavity of the main body stent 10; compared with the first branch stent 81 and the second branch stent 82 being arranged side by side in the radial direction within the main body stent 10, in this embodiment, disposing the free end of the second branch stent 82 outside the main body stent 10 can also enable the guide wire or the outer branch stent 500 to enter the corresponding branch stent more accurately and reduce the risk of the guide wire mistakenly entering another branch stent. Exemplarily, the length extension direction of the second branch stent 82 is perpendicular to the axial direction.

[0083] Please refer to Figure 5 and Figure 6 , in some embodiments, the first branch stent 81 is disposed within the main body stent 10, and the first branch stent 81 communicates with the groove 5; the second branch stent 82 and the first branch stent 81 are disposed on one side of the axial direction of the groove 5. Exemplarily, the second branch stent 82 and the first branch stent 81 are disposed on the side where the proximal end of the groove 5 is located, that is, both the second branch stent 82 and the first branch stent 81 are disposed in the proximal segment 2 of the main body stent 10. If the first branch stent 81 and the second branch stent 82 are arranged side by side in the radial direction on the side where the proximal end of the groove 5 is located, a triangular region is formed by enclosing the part of the first branch stent 81 adjacent to the second branch stent 82, the part of the second branch stent 82 adjacent to the first branch stent 81, and the inner wall of the main body stent 10. The triangular region is affected by the blood flow and will form a vortex, which will affect the blood flow direction in the inner cavity of the main body stent 10. In this embodiment, by disposing the second branch stent 82 outside the main body stent 10, the first branch stent 81 and the second branch stent 82 on one side of the axial direction of the groove 5 will not form a triangular region with the main body stent 10, so that the influence on the blood flow direction in the inner cavity of the main body stent 10 can be reduced.

[0084] Please refer to Figure 5 , in some embodiments, a guiding section 812 is formed at the distal end of the first branch stent 81, and the cross-sectional area of the guiding section 812 extends from the proximal end to the distal end in a gradually increasing manner. The distal end of the first branch stent 81 is designed as a flared guiding section 812, and the guiding section 812 can play a guiding role in the entry of the guide wire or the outer branch stent 500.

[0085] Please refer to Figure 7 , exemplarily, the proximal end of the covered stent 100 is upward and the distal end of the covered stent 100 is downward. The second branch stent 82 is arranged on the right side of the first branch stent 81 to better adapt to the three branch vessels 200 near the aortic arch 300. The second branch stent 82 is used for implanting Figure 1 into the leftmost one of the branch vessels 200. After the second branch stent 82 is implanted into the corresponding branch vessel 200, it can play a positioning role for the covered stent 100 to a certain extent, so that the groove 5 is aligned with the other two branch vessels 200; after the second branch stent 82 is implanted into the corresponding branch vessel 200, the second branch stent 82 does not interfere with the implantation of the other two branch vessels 200 into the corresponding outer branch stents 500, nor does it interfere with the connection between the outer branch stent 500 and the corresponding inner branch stent 8.

[0086] In some embodiments, the first branch stent 81 can also be arranged outside the main body stent 10. For example, one end of the first branch stent 81 is fixedly connected and communicated with the main body stent 10, the other end is a free end and has a branch opening, and the free end of the first branch stent 81 is arranged outside the main body stent 10. The length extension direction of the first branch stent 81 intersects the axial direction. The first branch stent 81 and the second branch stent 82 are arranged along the axial direction of the groove stent 100 and are arranged on the proximal section 2. That is, the first branch stent 81 and the second branch stent 82 are respectively used to communicate with the two branch vessels 200. After the first branch stent 81 and the second branch stent 82 communicate with the corresponding branch vessels 200, the groove 5 of the covered stent 100 is aligned with the openings of the other branch vessels 200, which can effectively reduce the situation that it is difficult for the groove 5 to be aligned with the corresponding branch vessels 200 due to the easy deflection of the covered stent 100 during release; in addition, by arranging the branch openings at the free ends of the first branch stent 81 and the second branch stent 82 outside the main body stent 10, the first branch stent 81 and the second branch stent 82 can be implanted into the branch vessels 200 without occupying the space of the inner cavity of the main body stent 10, thereby further reducing the occupation of the inner cavity of the main body stent 10 by the branch stents and further increasing the blood flow in the inner cavity of the main body stent 10. In other embodiments, the covered stent 100 further includes a third branch stent 83, and the third branch stent 83 is arranged on the distal side of the groove 5. The third branch stent 83 is arranged outside the main body stent 10; or, the third branch stent 83 is arranged in the inner cavity of the main body stent 10.

[0087] In other embodiments, the first branch stent 81 and the second branch stent 82 may also be disposed at the distal end of the groove 5, and the third branch stent 83 is disposed at the proximal end of the groove 5. In other embodiments, one or more of the first branch stent 81, the second branch stent 82, and the third branch stent 83 may be omitted.

[0088] Exemplarily, an annular support member (not shown in the figure) is provided at the edge of each branch stent to better maintain the shape of the branch opening, and the annular support member can be made of a radiopaque material, which can provide a support function and can be visualized during the operation to better indicate the position of the branch opening.

[0089] Please refer to Figure 8 , in some embodiments, the covered stent 100 includes a support structure 7, and the support structure 7 includes a bottom support member 71, and the bottom support member 71 is used to support the bottom 51 of the groove 5. Exemplarily, the bottom 51 of the groove includes a bottom film 51a, and the bottom support member 71 is used to support the bottom film 51a. The setting of the bottom support member 71 is beneficial to better maintain the shape of the inner cavity of the main stent 10 and / or the bottom 51 of the groove, and can reduce or avoid the excessive bulging of the bottom area of the groove where the bottom support member 71 is located toward the groove opening 52 direction, so as to occupy too much space of the groove 5, and thus can reduce the risk that the bottom 51 of the groove blocks the guide wire or the outer branch stent 500 from entering the inner branch stent 8; in addition, it can also maintain sufficient inner cavity space for the main stent 10.

[0090] Please refer to Figure 9 and Figure 10 , in some embodiments, the bottom support member 71 includes two support portions 711 spaced along the width direction of the bottom 51 of the groove (or the radial direction, the width direction of the groove 5), and the bottom film 51a includes a blank bottom film section 511. The blank bottom film section 511 means that this area only includes the film and does not include other support structures. In the width direction of the bottom 51 of the groove, the bottom film section 511 is located between the two support portions 711; the two support portions 711 can move relative to each other so that the bottom film section 511 can be deformed. Such a setting enables the bottom support member 71 to reduce or avoid the excessive bulging of the bottom area of the groove where the bottom support member 71 is located toward the groove opening 52 direction, so as to occupy too much space of the groove 5, thereby reducing the risk that the bottom 51 of the groove blocks the guide wire or the outer branch stent 500 from entering the inner branch stent 8; at the same time, it can also enable the bottom support member 71 to maintain good lateral bending performance (that is, the performance of bending toward the radial side of the groove 5), so that the covered stent 100 can well adapt to the curved shape of the blood vessel and better fit the blood vessel wall.

[0091] In some embodiments, the two support portions 711 can move relative to each other so that the bottom film-covered section 511 can deform to form a limiting groove 51 for radially limiting the sheath core 600. For the film-covered stent 100 of this embodiment, in actual application, the film-covered stent 100 can be first compressed and assembled in a conveyor (such as compressed into a delivery sheath). When the film-covered stent 100 is compressed in the conveyor, since the two support portions 711 of the film-covered stent 100 can move relative to each other, the blank bottom film-covered section 511 can deform to form a limiting groove 512, and at least a part of the sheath core 600 of the conveyor can be received in the limiting groove 512, so that the limiting groove 512 can hinder the displacement of the sheath core 600 in the radial direction to a certain extent. For example, the limiting groove 512 can radially limit the sheath core 600. If the above-mentioned limiting groove 512 is not provided, when the film-covered stent 100 is compressed and assembled into the conveyor, the sheath core 600 of the conveyor may be radially offset outside the area where the groove 5 is located; during the implantation process of the film-covered stent 100, after the conveyor (including the sheath core 600) enters the aortic arch 300, it will abut against the supra-arch region 301, so that during the release process of the film-covered stent 100, it can only expand in the direction away from the sheath core 600. If the sheath core is radially offset outside the area where the groove 5 is located during assembly, after the film-covered stent 100 is released, its groove 5 will also deviate from the supra-arch region 301 accordingly. The branch vessels 200 connected to the aortic arch 300 are usually located near the supra-arch region 301. If the release position of the groove 5 deviates far from the supra-arch region 301, it may cause the groove 5 to be difficult to align with the branch vessels 200, resulting in the film-covered stent 100 blocking the opening of the branch vessels 200, and further causing the blood flow of the branch vessels 200 to be blocked. Since the limiting groove 512 formed by the bottom film-covered section 511 of the film-covered stent 100 of this embodiment can hinder the displacement of the sheath core 600 in the radial direction to a certain extent before the film-covered stent 100 is released, during the process of withdrawing the sheath of the film-covered stent 100, the sheath core 600 can be manually placed at the position where the limiting groove 512 is located to reduce the probability of the sheath core 600 deviating relative to the groove 5. Thus, after the film-covered stent 100 is released, its groove 5 can more accurately align with the branch vessels 200, reducing the probability of the film-covered stent 100 blocking or clogging the branch vessels 200, and further ensuring that the blood flow of the branch vessels 200 can flow normally and smoothly, reducing complications caused by poor blood flow. After the film-covered stent 100 is implanted into the target cavity and released from the conveyor, the bottom film-covered section 511 naturally unfolds, and the bottom film-covered section 511 releases the radial limit on the sheath core 600, that is, the bottom film-covered section 511 does not form a limiting groove 512 for radially limiting the sheath core 600. Therefore, when the sheath core 600 is withdrawn from the target cavity, the sheath core 600 will not pull the bottom of the groove 51, resulting in damage or even breakage of the bottom film 51a.

[0092] Exemplarily, when the covered stent 100 is loaded in the delivery device, the sheath core 600 can pass through the inner cavity of the middle section 3. At this time, the bottom covered section 511 forms a limiting groove 512 that bulges toward the groove opening 52 to radially limit the sheath core 600; alternatively, the sheath core 600 can also be located outside the inner cavity of the middle section 3. The sheath core 600 enters the proximal section 2 through the groove 5. At this time, the bottom covered section 511 forms a limiting groove 512 that depresses toward the direction away from the groove opening 52 (i.e., bulges toward the inner cavity of the main stent 10) to radially limit the sheath core 600.

[0093] It can be understood that the regions corresponding to the two support portions 711 in the covered stent 100 are the first region 50a and the second region 50b respectively. The first region 50a, the bottom covered section 511, and the second region 50b are arranged along the width direction of the groove bottom 51. The two radial sides of the bottom covered section 511 (i.e., the sides in the width direction of the bottom covered section 511) are respectively connected to the first region 50a and the second region 50b. The blank bottom covered section 511 means that no support structures such as support coils, corrugated units, or support wires are provided on the bottom covered section 511. Therefore, the radial support force of the bottom covered section 511 is less than that of the first region 50a and the second region 50b on both sides. When being radially squeezed, the first region 50a and the second region 50b where the two support portions 711 are located can move relative to each other, such as approaching or separating from each other, so that the bottom covered section 511 can be deformed to form the limiting groove 512 for radially limiting the sheath core 600. Exemplarily, the two support portions 711 spaced apart in the radial direction (i.e., along the width direction of the groove bottom 51) are respectively denoted as the first support portion 711a and the second support portion 711b.

[0094] The number of the bottom support members 71 can be set according to actual needs, such as one, two, three, or more. Please refer to Figure 9, in some embodiments, the covered stent 100 includes three bottom supports 71 arranged axially in sequence, namely a first bottom support 71a, a second bottom support 71b, and a third bottom support 71c. In this embodiment, the first bottom support 71a is disposed in the proximal region of the bottom of the groove 51, the third bottom support 71c is disposed in the distal region of the bottom of the groove 51, and the second bottom support 71b is disposed between the proximal region and the distal region of the bottom of the groove 51. In other embodiments, the relative positions between the first bottom support 71a, the second bottom support 71b, and the third bottom support 71c can also be designed as other positional relationships according to actual needs. For example, the third bottom support 71c is disposed in the proximal region of the bottom of the groove 51, and the first bottom support 71a is disposed in the distal region of the bottom of the groove 51, etc. The number of the first bottom support 71a, the second bottom support 71b, and the third bottom support 71c can all be designed according to actual requirements. For example, they can all be one, two, three, or more. Exemplarily, the number of the first bottom support 71a is one, the number of the second bottom support 71b includes at least two, the number of the third bottom support 71c is one, and one first bottom support 71a, two second bottom supports 71b, and one third bottom support 71c are arranged axially.

[0095] It can be understood that the covered stent 100 includes a plurality of bottom supports 71 arranged axially, and adjacent bottom supports 71 can be connected or not. Exemplarily, the plurality of bottom supports 71 are sequentially arranged at intervals from the proximal end to the distal end, so that the bottom of the groove 51 can be bent in segments, enabling the bottom of the groove 51 to have good bending flexibility and lateral bending performance, which is beneficial for the bottom of the groove 51 to better conform to the lateral bending of the covered stent 100, enabling the bottom of the groove 51 and the covered stent 100 to better adapt to the lateral bending shape of the blood vessel, improving the wall attachment of the covered stent 100, and reducing the risk of blood leakage and thrombus formation.

[0096] In some embodiments, at least one of the first bottom support member 71a, the second bottom support member 71b, and the third bottom support member 71c respectively includes two support portions 711 and a bottom film covering section 511, so that the bottom film covering 51a can form a limiting groove 512, thereby radially limiting the sheath core 600. Exemplarily, at least two of the first bottom support member 71a, the second bottom support member 71b, and the third bottom support member 71c respectively include two support portions 711 and a bottom film covering section 511 to improve the radial limiting ability for the sheath core 600. For example, the first bottom support member 71a and the second bottom support member 71b respectively include two support portions 711 and a bottom film covering section 511, and the third bottom support member 71c is an integral structure. There is no blank bottom film covering section 511 in the radial area where the third bottom support member 71c is located, that is, there are no two parts spaced apart by the bottom film covering section 511 in the middle of the third bottom support member 71c along the width direction of the groove bottom 51. Another example is that the first bottom support member 71a and the third bottom support member 71c respectively include two support portions 711 and a bottom film covering section 511, and the second bottom support member 71b is an integral structure. There is no blank bottom film covering section 511 in the radial area where the second bottom support member 71b is located, that is, there are no two parts spaced apart by the bottom film covering section 511 in the middle of the second bottom support member 71b along the width direction of the groove bottom 51. Still another example is that the second bottom support member 71b and the third bottom support member 71c respectively include two support portions 711 and a bottom film covering section 511, and the first bottom support member 71a is an integral structure. There is no blank bottom film covering section 511 in the radial area where the first bottom support member 71a is located, that is, there are no two parts spaced apart by the bottom film covering section 511 in the middle of the first bottom support member 71a along the width direction of the groove bottom 51.

[0097] In other embodiments, the bottom film covering section 511 may be provided only on the second bottom support member 71b, and not on the first bottom support member 71a and the third bottom support member 71c located at the ends. The second bottom support member 71b located in the middle region can more flexibly respond to the action of the radial force to form the limiting groove 512.

[0098] Please refer to Figure 11, in some embodiments, the first bottom support member 71a, the second bottom support member 71b, and the third bottom support member 71c each include two support portions 711 spaced apart along the width direction of the groove bottom 51, and a bottom film segment 511 is provided between the two support portions 711. Exemplarily, the two support portions 711 of the first bottom support member 71a are spaced apart along the width direction of the groove bottom 51, and a bottom film segment 511 is provided between the two support portions 711 of the first bottom support member 71a, denoted as the first film segment 511a; the two support portions 711 of the first bottom support member 71a can move relative to each other so that the first film segment 511a can be deformed to form a limiting groove 512 for radially limiting the sheath core 600. The two support portions 711 of the second bottom support member 71b are spaced apart along the width direction of the groove bottom 51, and a bottom film segment 511 is provided between the two support portions 711 of the second bottom support member 71b, denoted as the second film segment 511b; the two support portions 711 of the second bottom support member 71b can move relative to each other so that the second film segment 511b can be deformed to form a limiting groove 512 for radially limiting the sheath core 600. The two support portions 711 of the third bottom support member 71c are spaced apart along the width direction of the groove bottom 51, and a bottom film segment 511 is provided between the two support portions 711 of the third bottom support member 71c, denoted as the third film segment 511c; the two support portions 711 of the third bottom support member 71c can move relative to each other so that the bottom film segment 511c can be deformed to form a limiting groove 512 for radially limiting the sheath core 600. The first film segment 511a, the second film segment 511b, and the third film segment 511c are arranged along the conveying direction of the sheath core 600. The first film segment 511a, the second film segment 511b, and the third film segment 511c can respectively form a limiting groove 512 for radially limiting the sheath core 600, thereby improving the radial limiting ability of the sheath core 600, effectively reducing the probability of the sheath core 600 deviating relative to the groove 5, and reducing the probability of the covered stent 100 blocking or occluding the branch blood vessel 200.

[0099] In some embodiments, the extension dimension (or width, radial extension dimension) of the bottom film covering section 511 in the width direction of the bottom of the groove 51 is greater than half of the circumference of the sheath core 600. The bottom film covering section 511 can wrap more than half of the circumference of the sheath core 600 in the radial direction, that is, the groove wall of the limiting groove 512 can wrap more than half of the circumference of the sheath core 600 in the radial direction to ensure better restraint of the sheath core 600. If the radial extension length of the bottom film covering section 511 is exactly equal to the circumference of the sheath core 600 and still wraps the sheath core 600 after the film covering stent 100 is implanted into the target lumen, under the action of the radial extrusion force of the target lumen on the film covering stent 100, if the two support portions 711 on both sides of the bottom film covering section 511 just abut against each other, it may be difficult to withdraw the sheath core 600 (not impossible to withdraw, but the limiting groove 512 has a strong radial restraint on the sheath core 600 and is difficult to withdraw radially, so it is recommended to withdraw along the axial direction). For this reason, exemplarily, the extension dimension of the bottom film covering section 511 in the width direction of the bottom of the groove 51 may be greater than half of the circumference of the sheath core 600, but not equal to the circumference of the sheath core 600. For example, the extension dimension of the bottom film covering section 511 in the width direction of the bottom of the groove 51 is greater than or less than the circumference of the sheath core 600, so that on the basis of ensuring a good restraint and limiting effect on the sheath core 600, the sheath core 600 can be more easily withdrawn from the limiting groove 512 when the film covering stent 100 is released. In other embodiments, the extension dimension of the bottom film covering section 511 in the width direction of the bottom of the groove 51 may also be equal to the circumference of the sheath core 600; or, the extension dimension of the bottom film covering section 511 in the width direction of the bottom of the groove 51 may also be less than half of the circumference of the sheath core 600.

[0100] In some embodiments, the inner branch stent 8 includes a branch opening facing the groove 5. The bottom film covering section 511 is axially opposite to the branch opening. The extension dimension of the bottom film covering section 511 in the width direction of the bottom of the groove 51 may be less than the diameter of the branch opening. Since the extension dimension of the bottom film covering section 511 in the width direction of the bottom of the groove 51 is less than the diameter of the branch opening, even if the bottom film covering section 511 is relatively close to the branch opening and the bottom film covering 51a and the support structure 7 are radially extruded to cause the bottom film covering section 511 to deform and form the limiting groove 512, the bottom film covering section 511 is not likely to bulge and completely block the branch opening or block the guide wire or the outer branch stent 500 from entering the branch opening, and can ensure that the guide wire or the outer branch stent 500 can smoothly enter the inner branch stent 8 on the premise that the bottom film covering section 511 forms the limiting groove 512 for radially limiting the sheath core 600.

[0101] Referring to FIG. 12(A), in some embodiments, the edges of the first branch port 811 and the second branch port 821 connected to the bottom of the groove 51 form a raised gap 54 that bulges upward. The bottom film covering section 511 is axially opposite to the raised gap 54. The edges of both the first branch port 811 and the second branch port 821 connected to the bottom of the groove 51 (e.g., connected to the bottom film 51a) form a shape similar to a slightly curved "W", and the pointed corner position of the middle bulge of the "W" shape forms the raised gap 54 that bulges upward (i.e., in the direction towards the upper edges of the first branch port 811 and the second branch port 821). When the bottom of the groove 51 is subjected to a radial squeezing force, the upwardly bulging raised gap 54 can cooperate with the bottom film covering section 511 to achieve a better limiting effect on the sheath core 600.

[0102] In addition, please also refer to Figure 9 , when the bottom film covering section 511 is provided on the first bottom support member 71a in the proximal region of the bottom of the groove 51, and the bottom film covering section 511 axially penetrates the first bottom support member 71a and is axially opposite to and connected to the raised gap 54. After the film covering stent 100 is implanted, under the action of the radial squeezing of the target lumen, the upwardly bulging raised gap 54 can guide the bottom film covering section 511 to bulge upward accordingly, playing a certain guiding role near the branch port. The bottom film covering sections 511 provided on the radial two sides of the bottom film covering section 511 can well maintain the shape of the bottom film 51a in the vicinity of the first branch port 811 and the second branch port 821. The bottom film 51a in the vicinity of the first branch port 811 and the second branch port 821 is not prone to bulging or irregular deformation after the film covering stent 100 is implanted into the target lumen, thus causing blockage of the branch port. The bottom support members 71 at the axial two ends of the bottom of the groove 51 can maintain a certain distance from the branch port, and the range value of this distance is 1 mm to 3 mm; such a setting is beneficial for the raised gap 54 to better guide the bottom film covering section 511 to bulge upward when the groove 5 is subjected to radial squeezing, and at the same time, it can also avoid the bottom support member 71 deforming axially and elongating to abut against the annular support member at the branch port during the radial compression process due to too small a distance, making it difficult to continue radial contraction deformation. It can be understood that in other embodiments, the annular support member can be omitted, and the distance between the bottom support members 71 at the axial two ends of the bottom of the groove 51 and the branch port can be less than 1 mm, or even the two are in contact with each other.

[0103] Please refer to FIGS. 12(A) and 12(B). In some embodiments, the bottom support 71 further includes a coupling portion 712. The coupling portion 712 is respectively connected to the first support portion 711a and the second support portion 711b. The first support portion 711a and the second support portion 711b are arranged along the width direction of the bottom of the groove 51 and form a spaced space 713. The area of the bottom film 51a corresponding to the spaced space 713 is the bottom film section 511, that is, the coupling portion 712 and the bottom film section 511 are arranged along the axial direction, and the coupling portion 712 is closer to the axial end of the bottom of the groove 51 relative to the bottom film section 511. The setting of the coupling portion 712 is beneficial to improving the radial support ability of the bottom support 71 near the branch opening, and can better maintain the shape of the connection between the bottom of the groove 51 and the branch opening of the inner branch stent 8. In addition, when subjected to radial extrusion, the bottom film section 511 can deform to form a limiting groove 512, so that the bottom of the groove 51 can limit the sheath core 600. Exemplarily, please refer to FIG. 12(B). The coupling portion 712 includes overlapping waveform units 712a and waveform units 712b. The radial two ends of the waveform unit 712a are respectively connected to the radial two ends of the waveform unit 712b, and the waveform unit 712a and the waveform unit 712b have opposite phases, so as to form a plurality of support sub-units arranged in sequence in the radial direction. For example, the first grid, and the first grid can be a quadrilateral mesh such as a rhombus or a quasi-rhombus, or any other suitable shape. The coupling portion 712 and the support portion 711 can be movably connected. For example, the waveform unit 712a, the waveform unit 712b are movably connected to the first support portion 711a and the second support portion 711b (for example, hooked connection with each other), so that a certain degree of relative movement can occur axially at the connection between the coupling portion 712 and the support portion 711. Such a setting enables the coupling portion 712 and the support portion 711 to deform relatively independently. Therefore, when the bottom support 71 is located at the axial end of the groove 5, even if a large extrusion force is applied between the support portions 711, they can deform relatively independently without directly causing a large deformation of the coupling portion 712, and the coupling portion 712 can still well maintain the shape of the bottom film 51a near the branch opening.

[0104] Please refer to FIG. 12(B). The first support portion 711a includes a plurality of support sub-units arranged in sequence in the radial direction. For example, the support sub-units of the first support portion 711a are the second grid. The second support portion 711b includes a plurality of support sub-units arranged in sequence in the radial direction. For example, the support sub-units of the second support portion 711b are the third grid. The support sub-unit of the first support portion 711a closest to the bottom film segment 511 and the support sub-unit of the second support portion 711b closest to the bottom film segment 511 are not directly connected to the joint portion 712. For example, they are not directly hooked and connected to the joint portion 712, but are only connected thereto through the blank film. Such an arrangement is beneficial for the bottom support member 71 when being pressed, and the support sub-units of the first support portion 711a and the second support portion 711b closest to the bottom film segment 511 can more flexibly cause the bottom film segment 511 to deform and form the limiting groove 512. It can be understood that in other embodiments, the grids in the joint portion 712 and / or the support portion 711 can be replaced by one or more waves protruding towards the axial end of the groove 5, or any other suitable structure can be used as the support sub-unit. In other embodiments, the joint portion 712 and the support portion 711 can also be movably connected in other ways. For example, the joint portion 712 and the support portion 711 are only connected through the blank bottom film segment, or are hinged, and can also be movably connected by means of elastic members (such as springs, elastic wires), etc. In other embodiments, the joint portion 712 can be movably connected to only one support portion 711, and the relative independent deformation between the two can also be achieved to a certain extent. In other embodiments, the joint portion 712 and the support portion 711 may not adopt a movable connection.

[0105] Please refer to Figure 13, in some embodiments, the support portion 711 includes a mesh structure 714 and support units 715. Exemplarily, the mesh structure 714 and the support units 715 may be integrally woven from support wires made of a metal or other medical material with shape memory function. In other embodiments, the mesh structure 714 and the support units 715 may also be integrally cut. The mesh structure 714 includes a first radially side edge and a second radially side edge that are spaced apart along the width direction of the bottom of the groove 51. The first radially side edge is closer to the bottom film section 511 than the second radially side edge; the width of the axially end of the mesh structure 714 closer to the branch opening is smaller than the maximum width of the mesh structure 714. In other embodiments, the width of the mesh structure 714 may remain consistent. The support units 715 extend axially, and the support units 715 are connected to the first radially side edge of the mesh structure 714. Exemplarily, the support units 715 include multiple axially support wires 7151 arranged in sequence axially. The adjacent two axially support wires 7151 overlap and / or are hooked at the intersection. When subjected to radial extrusion, the bottom film section 511 can form a limiting groove 512, and the support units 715 can support the notch of the limiting groove 512, so that the bottom film section 511 can better wrap at least part of the sheath core 600, and further enable the limiting groove 512 formed by the bottom film section 511 to effectively limit the sheath core 600.

[0106] Please refer to Figure 14 , in some embodiments, the bottom support 71 includes multiple columns of cross units and deformable mesh holes 7143 formed by the overlapping of multiple first-direction support wires 7141 arranged at intervals and multiple second-direction support wires 7142 arranged at intervals. Each axially support wire 7151 and the corresponding first-direction support wire 7141 and / or second-direction support wire 7142 in the mesh structure 714 are of an integral structure and form an edge bending angle at the first radially edge of the mesh structure 714. The edge bending angle is an acute angle, and the supplementary angle of the edge bending angle is greater than the inner angle of the deformable mesh hole 7143 in the mesh structure 714. Exemplarily, please refer to Figure 13 and Figure 14, the support unit 715 includes a first axially supporting wire 7151a and a second axially supporting wire 7151b. The first axially supporting wire 7151a and the second axially supporting wire 7151b extend substantially axially (substantially axially extending means that the angle with the axis of the covered stent 100 does not exceed 10°). The proximal end of the first axially supporting wire 7151a is connected to a first-direction supporting wire 7141 (denoted as the first wire 7141a), and the distal end of the first axially supporting wire 7151a is connected to a second-direction supporting wire 7142 (denoted as the second wire 7142a). Moreover, the first wire 7141a, the first axially supporting wire 7151a, and the second wire 7142a are of an integral structure. The first wire 7141a and the first axially supporting wire 7151a form a first edge bending angle α, and the second wire 7142a and the first axially supporting wire 7151a form a second edge bending angle β. Both the first edge bending angle α and the second edge bending angle β are acute angles. The supplementary angle of the first edge bending angle α is equal to 180° - α, and the supplementary angle of the second edge bending angle β is equal to 180° - β. The supplementary angles of the first edge bending angle α and the second edge bending angle β are both greater than the interior angle within the deformable mesh hole 7143 in the mesh structure 714. The relative relationship between the second axially supporting wire 7151b and the corresponding first-direction supporting wire 7141 and second-direction supporting wire 7142 is the same and will not be elaborated here. Without the axially supporting wire 7151, the radial edge of the mesh structure 714 close to the bottom covering section 511 or a row of deformable mesh holes 7143 directly faces the bottom covering section 511. After the covered stent 100 is implanted, it will conform to the blood vessel bending and be affected by the impact of blood and the pulsation of the blood vessel. The angle of the sharp corner of the radial edge of the mesh structure 714 or the deformable mesh hole 7143 facing the bottom covering section 511 is too small, which may wear or pierce the bottom covering section 511. The supplementary angle of the edge bending angle is greater than the interior angle of the deformable mesh hole 7143 in the mesh structure 714, which can reduce the risk of the sharp corner at the edge of the mesh structure 714 wearing and piercing the covering film.

[0107] Please refer to Figure 13 and Figure 14, in some embodiments, the bottom support 71 further includes a deformable buffer unit 716 at the radial edge, and the buffer unit 716 is connected to the mesh structure 714. For example, in this embodiment, both radial edges of the first bottom support 71a and the third bottom support 71c each include a buffer unit 716; in other embodiments, only one radial edge of the bottom support 71 includes a buffer unit 716, or two or more buffer units 716 can be provided on each radial edge of the bottom support 71. In other embodiments, the above buffer unit 716 can be omitted. Since the buffer unit 716 is radially close to the radial edge of the groove 5, when the groove 5 is subjected to radial pressure, the buffer unit 716 is first subjected to force and deforms and moves, rather than immediately transmitting the force to the mesh structure 714, thereby playing a certain buffering role, being able to better maintain the overall shape of the bottom support 71, preventing the blocking of the branch port, and being beneficial to maintaining the shape of the bottom of the groove 51. Exemplarily, the buffer unit 716 includes a buffer rod 7161 and a connecting rod 7162. One end of the connecting rod 7162 is connected to the mesh structure 714, and the other end of the connecting rod 7162 is connected to the buffer rod 7161. The buffer rod 7161 is located at the radial edge of the bottom support 71, and the buffer rod 7161 is closer to the radial edge of the bottom support 71 than the connecting rod 7162. A buffer vertex 7163 is formed at the connection between the buffer rod 7161 and the connecting rod 7162. An active gap is formed between the buffer vertex 7163 and the mesh structure 714, so that the buffer vertex 7163 can move relative to the mesh structure 714, which is beneficial to improving the buffering effect of the buffer unit 716. The above buffer rod 7161 can be used to connect to the bottom film 51a at this position, and can preferentially deform under radial force to buffer the radial force, and then conduct the force that cannot be buffered to the connecting rod 7162, and the connecting rod 7162 moves to further buffer the radial force. In this embodiment, the buffer rod 7161 is substantially parallel to the radial edge of the groove 5, which is beneficial to its uniform force in the radial direction and can play a buffering role more sensitively and efficiently. In other embodiments, the buffer rod 7161 can be arranged at an angle, for example, an acute angle with the radial edge of the groove 5. Figure 14 The number of buffer rods 7161 in the buffer unit 716 is one, and a triangle or a quasi-triangle is formed by enclosing between the buffer rod 7161 and the connecting rod 7162. In other embodiments, the number of buffer units 716 can be multiple, and a quadrilateral or other polygon is formed by enclosing between multiple buffer rods 7161 and the connecting rod 7162. And when there are multiple buffer rods 7161, buffer vertices 7163 can also be formed at the connections of the mutually connected buffer rods 7161. It can be understood that the bottom support 71 in FIG. 12(B) and Figure 13 , Figure 14Although the structures of the bottom support member 71 in [reference] are different, the bottom support member 71 in FIG. 12(B) may also include a buffer unit 716.

[0108] Please refer to Figure 13 , in some embodiments, the bottom support member 71 located at the axial end of the bottom of the groove 51 includes a width reduction section X, which is located at the bottom of the groove 51 and whose width becomes smaller along the direction close to the inner branch bracket 8, so that the area of the bottom support member 71 close to the branch opening forms a trapezoid-like structure. For example, at least one of the first bottom support member 71a and the third bottom support member 71c includes a width reduction section X. The maximum radial dimension D2 (or width) of the first bottom support member 71a is greater than the radial dimension D1 of the proximal end of the first bottom support member 71a, and the maximum radial dimension of the third bottom support member 71c may be greater than the radial dimension of the distal end of the third bottom support member 71c. The purpose of this structure is that when the covered stent 100 is implanted and the bottom of the groove 51 is radially squeezed by the target cavity, the area of the bottom of the groove 51 connected to the branch opening can form a trapezoid-like guiding structure following the width reduction section X, which can better guide the guide wire and the outer branch bracket 500 into the branch opening.

[0109] Exemplarily, the structures of the first bottom support member 71a, the second bottom support member 71b, and the third bottom support member 71c are different; in other embodiments, at least two of the first bottom support member 71a, the second bottom support member 71b, and the third bottom support member 71c may also have the same structure. For example, please refer to Figure 13 , in combination with Figure 9 , both the first bottom support member 71a and the third bottom support member 71c include a mesh structure 714. The mesh structure 714 of the first bottom support member 71a and the mesh structure 714 of the third bottom support member 71c may be the same or different. Another example, please refer to Figure 13 , the second bottom support member 71b includes a first corrugated unit 7101 and a second corrugated unit 7102, and the first corrugated unit 7101 and the second corrugated unit 7102 are arranged in an overlapping and / or hooked manner. Exemplarily, the peaks of the first corrugated unit 7101 and the valleys of the second corrugated unit 7102 are axially opposite to each other.

[0110] Please refer to Figures 15 to 17(A), in some embodiments, the covered stent 100 includes the main stent 10 of any of the above embodiments and a limiting structure 9. The limiting structure 9 includes a limiting member 91 and a constraint member 92 for restricting the position of the limiting member 91. The limiting member 91 is detachably connected to the constraint member 92. When the covered stent 100 is in the first state, the limiting member 91 can be used to radially limit the target segment 601 of the sheath core 600 under the constraint of the constraint member 92. The target segment 601 is an axial section of the sheath core 600, and this axial region is located within the axial region between the proximal end and the distal end of the groove 5 (i.e., within the axial region of the middle section 3) in the first state. When the covered stent 100 is in the second state, the constraint member 92 can be disengaged from the limiting member 91 so that the limiting member 91 releases the restriction on the target segment 601.

[0111] For the covered stent 100 of the above embodiments, when the covered stent 100 is in the first state (such as the compressed state when compressed and assembled in the sheath of the delivery device), the limiting member 91 of the limiting structure 9 can be used to radially limit the target segment 601 of the sheath core 600 under the constraint of the constraint member 92. When it is necessary to implant the covered stent 100 into the target cavity, the covered stent 100 is implanted into the target cavity through the delivery device. When the covered stent 100 located in the target cavity is released and expanded from the delivery device, the target segment 601 of the sheath core 600 of the delivery device abuts against the supra-aortic region 301 of the aortic arch 300, and the covered stent 100 expands in a direction away from the target segment 601 of the sheath core 600. Before the covered stent 100 is fully expanded, since the limiting member 91 can radially limit the sheath core 600 under the constraint of the constraint member 92, the probability of the sheath core 600 deviating from the bottom of the groove 5 (such as the bottom covering 51a) can be reduced. As a result, after the covered stent 100 is implanted, its groove 5 can more accurately align with the branch vessel, reducing the probability of the covered stent 100 blocking or occluding the branch vessel 200, and thus ensuring that the blood flow in the branch vessel 200 can flow normally and smoothly, reducing complications caused by poor blood flow. When the covered stent 100 is in the second state, the constraint member 92 can be disengaged from the limiting member 91 so that the limiting member 91 releases the restriction on the target segment 601, so that when the sheath core 600 is withdrawn from the target cavity, the sheath core 600 will not pull the bottom of the groove 5, resulting in damage or even breakage of the bottom covering.

[0112] Exemplarily, the first state is the compressed state corresponding to the covered stent 100 being compressed and assembled in the delivery device, and the second state is the fully expanded state corresponding to the covered stent 100 being implanted into the target cavity and released from the sheath of the delivery device. In other embodiments, the first state can also be a semi-expanded state between the compressed state and the fully expanded state, and the second state is the fully expanded state; or, the first state is the compressed state corresponding to the covered stent 100 being compressed and assembled in the delivery device, and the second state is a semi-expanded state between the compressed state and the fully expanded state.

[0113] In some embodiments, the restraint member 92 includes a restraint wire. When the covered stent 100 is in the first state, the restraint wire can pass through the limiting member 91 so that the limiting member 91 can be used to radially limit the target segment 601. When the covered stent 100 is in the second state, the restraint member 92 can move axially so that the restraint wire disengages from the limiting member 91, thereby enabling the limiting member 91 to release the restriction on the target segment 601. The diameter of the restraint wire is small, causing less trauma to the organism when implanting the covered stent 100 into the target cavity. Exemplarily, one end of the restraint wire is used to enter the target cavity together with the main body stent 10, and the other end of the restraint wire can extend out of the organism having the target cavity to facilitate withdrawing the restraint wire outward, so that the restraint wire disengages from the limiting member 91, thereby enabling the limiting member 91 to release the restriction on the target segment 601. In other embodiments, both ends of the restraint wire can enter the target cavity together with the main body stent 10. The restraint wire can be connected to the sheath core 600 or other components of the delivery device other than the sheath core 600. When the sheath core 600 or the delivery device is withdrawn, the restraint wire can be withdrawn together with the sheath core 600 or the delivery device.

[0114] The number of the limiting members 91 can be set according to actual needs, such as one, two, three or more. For example, the number of the limiting members 91 is two, and the two limiting members 91 are arranged at intervals along the axial direction to improve the radial limiting effect on the target segment 601.

[0115] Please refer to Figure 16 and FIG. 17(A). In some embodiments, the limiting member 91 includes a limiting wire 911, and the end of the limiting wire 911 can form a wire buckle portion 912. When the covered stent 100 is in the first state, the restraint member 92 can pass through the wire buckle portion 912 so that the limiting wire 911 can cooperate with the inner wall of the lumen of the main body stent to limit the target segment 601. When the covered stent 100 is in the second state, the restraint member 92 can be withdrawn from the wire buckle portion 912 so that the limiting wire 911 releases the restriction on the target segment 601. The limiting member 91 with this structure is simple in structure and light in weight. Exemplarily, both the limiting wire 911 and the restraint wire are made of materials with biocompatibility and little damage to the organism. Exemplarily, when the covered stent 100 is in the first state, one of the target segment 601 and the wire buckle portion 912 is located in the lumen of the main body stent 10, and the other is located in the groove 5. For example, when the covered stent 100 is in the first state, the target segment 601 is located in the lumen of the main body stent 10, and the wire buckle portion 912 is located in the groove 5.

[0116] Please refer to FIG. 17(A). In some embodiments, the wire buckle portion 912 includes a first wire buckle 9121 and a second wire buckle 9122. The first wire buckle 9121 can be formed at one end of the limiting wire 911; the second wire buckle 9122 can be formed at the other end of the limiting wire 911; when the covered stent 100 is in the first state, the restraint 92 can pass through the first wire buckle 9121 and the second wire buckle 9122, so that the limiting wire 911 can be engaged with the mating limiting target segment 601 of the main stent; when the covered stent 100 is in the second state, the restraint 92 can disengage from the first wire buckle 9121 and the second wire buckle 9122, so that the limiting wire 911 releases the restriction on the sheath core 600. When it is necessary to assemble the covered stent 100 onto the delivery device, the restraint 92 can be passed through the first wire buckle 9121 and the second wire buckle 9122, so that the limiting wire 911 can bind the target segment 601 to a preset area, thereby realizing the radial limitation of the sheath core 600; after the covered stent 100 is implanted into the target cavity and released from the delivery device, the restraint 92 can be moved along the withdrawal direction by means of an instrument such as a delivery device or directly operating the restraint 92, so that the restraint 92 disengages from the first wire buckle 9121 and the second wire buckle 9122. At this time, the two ends of the limiting wire 911 are no longer restricted by the restraint 92, and the binding of the limiting wire 911 to the target segment 601 is weakened or even released, providing a guarantee for the smooth removal of the sheath core 600 from the target cavity. The first wire buckle 9121 and the second wire buckle 9122 can restrain and limit the sheath core 600 at two different positions in the axial direction or the conveying direction of the sheath core 600, improving the reliability and stability of the radial limitation of the sheath core 600 when the covered stent 100 is in the first state. Exemplarily, when the covered stent 100 is in the first state, the limiting wire 911 penetrates through the bottom film 51a, so that the sheath core 600 passes through the inner cavity of the middle section 3 (please refer to Figure 2 ), and the wire buckle portion 912 is located in the other of the inner cavity of the middle section 3 and the groove 5. In other embodiments, one of the first wire buckle 9121 and the second wire buckle 9122 can also be omitted.

[0117] Please refer to FIG. 17 (B). Exemplarily, the limiting wire 911 can be connected to the sheath core 600. The sheath core 600 is inserted into one of the inner cavity and the groove 5 of the main support 10, and the wire buckle portion 912 is located in the other of the inner cavity and the groove 5 of the middle section 3. Exemplarily, the number of limiting wires 911 includes two, and each limiting wire 911 is fixedly connected to the sheath core 600. For example, the limiting wire 911 includes a connecting section 9123, one end of which is fixedly connected to the sheath core 600 by bonding or the like, and the other end can penetrate the bottom coating 51a and form a wire buckle portion 912 for the constraint 92 to pass through. In other embodiments, the connecting section 9123 can be detachably connected to the sheath core 600. For example, a connecting wire is provided on the sheath core 600, and the connecting wire and the limiting wire 911 are connected to each other by a slipknot. In other embodiments, the number of the limiting lines 911 can be designed to be other numbers according to actual needs, such as one, three or more.

[0118] See also Figure 18 In some embodiments, the limiting member 91 includes a first limiting portion 913 and a second limiting portion 914. When the stent graft 100 is in the first state, the constraint member 92 passes through the first limiting portion 913 and the second limiting portion 914 to constrain the first limiting portion 913 and the second limiting portion 914 to separate from each other, so that the first limiting portion 913 and the second limiting portion 914 can limit the target segment 601 in the radial direction, thereby achieving radial limiting of the target segment 601; when the stent graft 100 is in the second state, the constraint member 92 can be separated from the first limiting portion 913 and the second limiting portion 914, so that the first limiting portion 913 and the second limiting portion 914 release the restriction on the target segment 601, so as to ensure that the sheath core 600 can be smoothly evacuated from the target cavity. The limiting member 91 of this structure is simple in structure, and the radial limiting and releasing operations of the target segment 601 are easy and fast. In this embodiment, the stopper 91 is located in the groove 5, and the sheath core 600 is inserted into the inner cavity of the main stent 10. When in the first state, the stopper 91 limits the target segment 601 through the bottom coating 51a. When in the second state, the stopper 91 is still retained in the groove 5. Even if the stopper 91 is not connected to the groove bottom 51, the groove bottom 51 and the mesh cover 61 can well limit the stopper 91 in the groove 5 to prevent the stopper 91 from escaping from the coated stent 100. In other embodiments, the stopper 91 can be connected to the groove bottom 51, and it can be set in the groove 5 or in the inner cavity of the main stent 10. In other embodiments, the stopper 91 can be made of a degradable material such as polylactic acid, which can be degraded in the body and can promote the rapid thrombosis of the groove 5 to improve the endothelialization process of the coated stent 100.

[0119] See also Figures 18 to 20(A), in some embodiments, the first restricting portion 913 includes a first connecting sub-portion 9131 and a first restricting sub-portion 9132 connected to the first connecting sub-portion 9131, and the second restricting portion 914 includes a second connecting sub-portion 9141 and a second restricting sub-portion 9142 connected to the second connecting portion; when the covered stent 100 is in the first state, the restraining member 92 can pass through the first connecting sub-portion 9131 and the second connecting sub-portion 9141, so that the first restricting sub-portion 9132 and the second restricting sub-portion 9142 can radially restrict the target segment 601, thereby achieving radial restraint on the target segment 601; when the covered stent 100 is in the second state, the restraining member 92 can disengage from the first connecting sub-portion 9131 and the second connecting sub-portion 9141, so that the first connecting sub-portion 9131 and the second connecting sub-portion 9141 move away from each other, and further enabling the first restricting sub-portion 9132 and the second restricting sub-portion 9142 to release the restriction on the target segment 601 to ensure that the sheath core 600 can be smoothly withdrawn from the target cavity. Exemplarily, the first connecting sub-portion 9131 is provided with a first connecting hole 91311, and the second connecting sub-portion 9141 is provided with a second connecting hole 91411. When the covered stent 100 is in the first state, the restraining member 92 can pass through the first connecting hole 91311 and the second connecting hole 91411, thereby restraining the first restricting portion 913 and the second restricting portion 914, so that the first restricting sub-portion 9132 and the second restricting sub-portion 9142 can form a restricting space 915 for radially restricting the target segment 601, and the width of the opening 9151 of the restricting space 915 is smaller than the diameter of the sheath core 600. The first connecting hole 91311 and the second connecting hole 91411 are arranged along the axial direction of the groove 5 to form a channel for the restraining member 92 to pass through. The first connecting hole 91311 and the second connecting hole 91411 can be coaxially arranged or non-coaxially arranged, as long as the formed channel can allow the restraining member 92 to pass through, and when the restraining member 92 is passed through the channel, the width of the opening 9151 of the restricting space 915 can always be smaller than the diameter of the sheath core 600. It can be understood that the first restricting sub-portion 9132 and the second restricting sub-portion 9142 can be connected to the bottom film 51a or not connected to the bottom film 51a.

[0120] Please refer to Figure 18 , in some embodiments, the first restricting portion 913 and the second restricting portion 914 can be used to cooperate to form a restricting space 915, and at least one of the first restricting portion 913 and the second restricting portion 914 is provided with a limiting portion 916 for restricting the increase of the opening 9151 of the restricting space 915; or, at least one of the first restricting portion 913 and the second restricting portion 914 is provided with a limiting portion 916 for restricting the increase and decrease of the opening 9151 of the restricting space 915, so as to ensure that when the covered stent 100 is in the first state, the first restricting portion 913 and the second restricting portion 914 can achieve radial limiting on the target segment 601 under the restraint of the restraining member 92.

[0121] In some embodiments, the limiting portion 916 can also be used to limit the reduction of the opening 9151 of the limiting space 915, so that the first limiting portion 913 and the second limiting portion 914 cooperate to form a limiting space 915 adapted to the diameter of the target segment 601 of the sheath core 600, reducing the damage to the sheath core 600 caused by the first limiting portion 913 and / or the second limiting portion 914.

[0122] Please refer to Figures 18 to 20(B) , in some embodiments, the limiting portion 916 includes a first limiting mechanism 916a, and the first limiting mechanism 916a is used to limit the increase of the opening 9151 of the limiting space 915. Exemplarily, the first limiting mechanism 916a includes a first limiting wall 9162 (for example, extending transversely, that is, in the direction from the first limiting sub-portion 9132 to the second limiting sub-portion 9142, or in the direction from the second limiting sub-portion 9142 to the first limiting sub-portion 9132) and a second limiting wall 9161 (for example, extending longitudinally, that is, in the direction from the first connection hole 91311 or the second connection hole 91411 to the limiting space 915, or in the direction from the limiting space 915 to the first connection hole 91311 or the second connection hole 91411). The second limiting wall 9161 and the first limiting wall 9162 are provided on the first limiting portion 913. The second limiting portion 914 includes a first mating wall 9144 (for example, extending transversely) and a second mating wall 9143 (for example, extending longitudinally). The second limiting wall 9161 can abut against the second mating wall 9143 to limit the rotation of the second limiting portion 914 relative to the first limiting portion 913 in the first rotation direction, so as to limit the reduction of the opening 9151 of the limiting space 915. The first limiting wall 9162 can contact the first mating wall 9144 to limit the rotation of the second limiting portion 914 relative to the first limiting portion 913 in the second rotation direction opposite to the first rotation direction to limit the increase of the opening 9151 of the limiting space 915. Thus, when the covered stent 100 is in the first state, the restraint 92 can play a role in restraining the positions of the first limiting portion 913 and the second limiting portion 914, and the first limiting mechanism 916a can limit the rotation of the second limiting portion 914 between the second limiting wall 9161 and the first limiting wall 9162 in the direction opposite to the clamping direction, thereby playing a role in limiting the increase of the opening 9151 of the limiting space 915, so that the limiting structure 9 can perform reliable radial limiting on the sheath core 600. In other embodiments, the second limiting wall 9161 can be omitted.

[0123] Please refer to Figure 19, in some embodiments, the limiting portion 916 and the connecting sub-portion enclose an avoidance space 917 for avoiding the second limiting portion 914. When the constraining member 92 passes through the first limiting portion 913 and the second limiting portion 914, the avoidance space 917 can avoid a part of the second limiting portion 914, which is beneficial to reducing the sizes of the first limiting portion 913 and the second limiting portion 914.

[0124] Please refer to Figures 18 to 20(B) , in some embodiments, the limiting portion 916 includes a second limiting mechanism 916b, and the second limiting mechanism 916b is at least used to limit the movement of the first limiting portion 913 and the second limiting portion 914 along the length extension direction of the constraining member 92. Exemplarily, the second limiting mechanism 916b is also used to limit the increase of the opening 9151 of the limiting space 915. The second limiting mechanism 916b further includes a constraining groove 9163, and the constraining groove 9163 is provided in one of the first connecting sub-portion 9131 and the second connecting sub-portion 9141, and the other of the first connecting sub-portion 9131 and the second connecting sub-portion 9141 can be inserted into the constraining groove 9163 to at least limit the movement of the first limiting portion 913 and the second limiting portion 914 along the length extension direction of the constraining member 92. For example, the constraining groove 9163 is provided in the second connecting sub-portion 9141, and the first connecting sub-portion 9131 can be inserted into the constraining groove 9163, so that the two opposite groove walls of the constraining groove 9163 limit the first connecting sub-portion 9131 along the length direction of the constraining member 92, thereby realizing the limitation of the first limiting portion 913 and the second limiting portion 914 along the length extension direction of the constraining member 92. A third limiting wall 9164 (for example, extending transversely) and a fourth limiting wall 9165 (for example, extending longitudinally) are provided in the constraining groove 9163. The first limiting portion 913 includes a third mating wall 9145 (for example, extending transversely) and a fourth mating wall 9146 (for example, extending longitudinally). The fourth limiting wall 9165 can abut against the fourth mating wall 9146 to limit the second limiting portion 914 from rotating relative to the first limiting portion 913 in the first rotation direction, so as to limit the decrease of the opening 9151 of the limiting space 915. The third limiting wall 9164 can abut against the third mating wall 9145 to limit the second limiting portion 914 from rotating relative to the first limiting portion 913 in the second rotation direction opposite to the first rotation direction to limit the increase of the opening 9151 of the limiting space 915. In other embodiments, the fourth limiting wall 9165 can be omitted. In other embodiments, one of the first limiting mechanism 916a and the second limiting mechanism 916b can be omitted. In other embodiments, the number of the first limiting mechanism 916a and the second limiting mechanism 916b can be one or more.

[0125] Please refer to Figure 18 , in combination with Figure 15, in some embodiments, the edges of the first branch opening 811 of the first branch stent 81 and the second branch opening 821 of the second branch stent 82 connected to the bottom of the groove 51 form a raised clearance 54 that bulges upward, and the portion of the limiting structure 9 for connecting with the restraint 92 is axially opposite to the raised clearance 54. For example, the wire buckling portion 912 is axially opposite to the raised clearance 54. Another example is that the limiting space 915 is axially opposite to the raised clearance 54, which is beneficial to improving the radial limiting effect on the sheath core 600.

[0126] Please refer to Figure 21 and Figure 22 , in some embodiments, the covered stent 100 includes the main stent 10, the limiting channel 62, and two inner branch stents 8 of any one of the above embodiments, which are respectively denoted as the first branch stent 81 and the second branch stent 82. The first branch stent 81 and the second branch stent 82 are arranged side by side in the radial direction within the main stent 10. The first branch stent 81 is provided with a first branch opening 811 at the end closer to the groove 5, and the second branch stent 82 is provided with a second branch opening 821 at the end closer to the groove 5. The first branch opening 811 and the second branch opening 821 both face the groove 5, and the first branch opening 811 and the second branch opening 821 are both in communication with the groove 5; the limiting channel 62 is formed between the first branch stent 81 and the second branch stent 82, and the limiting channel 62 is used to limit the sheath core 600 in the radial direction.

[0127] For the covered stent 100 of the above embodiment, in actual application, the covered stent 100 can be first compressed and assembled on a conveyor (such as a delivery sheath). Before the covered stent 100 is released and detached from the conveyor, the sheath core 600 passes through the limiting channel 62, and the limiting channel 62 can radially limit the sheath core 600. When the covered stent 100 needs to be implanted into the target cavity, the covered stent 100 is implanted into the target cavity through the conveyor; when the covered stent 100 located in the target cavity is released and expanded from the conveyor, the sheath core 600 of the conveyor abuts against the supra-arch region 301 of the aortic arch 300, and the covered stent 100 expands in a direction away from the sheath core 600. Since the limiting channel 62 can radially limit the sheath core 600 before the covered stent 100 is fully expanded, the probability of the sheath core 600 deviating relative to the groove 5 can be reduced, so that the groove 5 of the covered stent 100 can be more accurately aligned with the branch vessel 200 after implantation, reducing the probability of the covered stent 100 blocking or occluding the branch vessel 200, and thus ensuring that the blood flow in the branch vessel 200 can flow normally and smoothly, reducing complications caused by poor blood flow. After the covered stent 100 is implanted into the target cavity and released from the conveyor, the sheath core 600 can be withdrawn axially from the target cavity.

[0128] Please refer to Figure 23, in some embodiments, the first branch stent 81 and the second branch stent 82 are arranged at a radial interval to form a limiting channel 62, and the limiting channel 62 is respectively communicated with the inner cavity of the main body stent 10 and the groove 5. In the covered stent 100 of this embodiment, a part of the first branch stent 81, a part of the second branch stent 82, and a part of the main body stent 10 jointly enclose to form the limiting channel 62. The structure of the limiting channel 62 for radially limiting the sheath core 600 is simple, reasonable and ingenious, and there is no need to additionally provide a limiting structure for radially limiting the sheath core 600, reducing the number of component settings.

[0129] Please refer to Figure 24 and Figure 25 , in some embodiments, the first branch stent 81 is provided with a blank film (denoted as the first blank film 813), the second branch stent 82 is provided with a blank film (denoted as the second blank film 822), and the first blank film 813 and the second blank film 822 are arranged side by side in the radial direction to form a limiting channel 62 between the first branch stent 81 and the second branch stent 82. The first blank film 813 and the second blank film 822 can move away from each other to make the limiting channel 62 in an open state, as Figure 24 shown; when a part of the outer branch stent 500 is implanted into the first branch stent 81 and / or the second branch stent 82 and the sheath core 600 does not pass through the limiting channel 62, the first blank film 813 and the second blank film 822 are attached to make the limiting channel 62 in a closed state, as Figure 25 shown. It can be understood that the first blank film 813 and the second blank film 822 refer to films without support structures such as corrugated rings or waveform units to support them. The radial support capabilities of the first blank film 813 and the second blank film 822 are small, including that the limiting channel 62 formed by the first blank film 813 and the second blank film 822 has good deformability. The limiting channel 62 can open when the sheath core 600 enters the limiting channel 62, and the limiting channel 62 can close when the sheath core 600 does not pass through the limiting channel 62 and a part of the outer branch stent 500 is implanted into the first branch stent 81 and / or the second branch stent 82, so as to prevent the blood in the inner cavity of the main body stent 10 from leaking out through the limiting channel 62. In other embodiments, waveform units can also be provided for support in the regions corresponding to the first blank film 813 and the second blank film 822.

[0130] Please refer to Figure 22 and Figure 24, in some embodiments, the first blank film 813 and the second blank film 822 respectively form the first channel wall and the second channel wall of the limiting channel 62. The first channel wall has a first wall edge 8131 and a second wall edge 8132 that are circumferentially spaced apart. The second channel wall has a third wall edge 8221 and a fourth wall edge 8222 that are circumferentially spaced apart. The first wall edge 8131 and the third wall edge 8221 are spaced apart and can form an open opening 63. The second wall edge 8132 is connected to the fourth wall edge 8222. The open opening 63 communicates with the limiting channel 62. The setting of the open opening 63 facilitates the insertion of the Tip head 610 (or called the end) of the sheath core 600 into the limiting channel 62 or the withdrawal of the sheath core 600 from the limiting channel 62. It can be understood that the channel wall of the limiting channel 62 can wrap the sheath core 600 with a circumference exceeding 1 / 5. For example, the channel wall of the limiting channel 62 can wrap the sheath core 600 with a circumference exceeding half, so that the limiting channel 62 can better limit the sheath core 600 in the radial direction. Another example is that the channel wall of the limiting channel 62 can wrap the sheath core 600 for one week to better radially limit the sheath core 600. Exemplarily, the main body bracket 10 includes an inner wall section 13 disposed opposite to the open opening 63. The inner wall section 13, the open opening 63, and the second wall edge 8132 are arranged in sequence. The inner wall section 13, the first channel wall, and the second channel wall cooperate to form the limiting channel 62. In this way, the requirements for the deformation ability of the first channel wall and the second channel wall can be reduced, so that both the first branch bracket 81 and the second branch bracket 82 can maintain a good shape, thereby having enough space for blood to flow through. In addition, the inner wall section 13, the first channel wall, and the second channel wall cooperate to form the limiting channel 62. Compared with the solution in which the first wall edge 8131 and the third wall edge 8221 are fixedly connected to each other without setting the open opening 63, when the sheath core 600 is withdrawn from the limiting channel 62, the sheath core 600 abuts against the inner wall section 13 and withdraws, so that the Tip head 610 of the sheath core 600 is not easily hooked on the edge of the opening at the axial end of the limiting channel 62 that is farther away from the groove 5, and further, the corresponding areas of the first branch bracket 81 and / or the second branch bracket 82 are not easily deformed or displaced.

[0131] Please refer to Figure 26 and 27, in some embodiments, the first blank film 813 and the second blank film 822 respectively form the first channel wall and the second channel wall of the limiting channel 62. The first channel wall has a first wall edge 8131 and a second wall edge 8132 that are spaced apart in the radial direction. The second channel wall has a third wall edge 8221 and a fourth wall edge 8222 that are spaced apart in the radial direction. The first wall edge 8131 is connected to the third wall edge 8221, and the second wall edge 8132 is connected to the fourth wall edge 8222, so that the channel wall of the limiting channel 62 forms a closed annular structure. The first blank film 813 and the second blank film 822 can move away from each other to open the limiting channel 62 for the sheath core 600 to enter the limiting channel 62, as Figure 26 shown; when the sheath core 600 is withdrawn from the limiting channel 62, the first blank film 813 and the second blank film 822 are attached to each other to close the limiting channel 62. When a part of the outer branch stent 500 is implanted into the first branch stent 81 and / or the second branch stent 82, the first blank film 813 and the second blank film 822 are attached more closely, as Figure 27 shown. When the limiting channel 62 is in a closed state, the attachment of the first blank film 813 and the second blank film 822 can effectively seal the limiting channel 62 to prevent blood from leaking out through the limiting channel 62.

[0132] Please refer to Figure 28 and Figure 29 , in some embodiments, an end support 64 is provided at the opening of the limiting channel 62 at the axial end farther from the groove 5. The end support 64 extends circumferentially along the limiting channel 62; when the inner branch stent 8 is in a natural state, the opening at the axial end of the limiting channel 62 farther from the groove 5 is open; when a part of the outer branch stent 500 is implanted into the inner branch stent 8, the opening at the axial end of the limiting channel 62 farther from the groove 5 is closed, which can prevent the blood flow in the main stent 10 from leaking out through the limiting channel 62. The setting of the end support 64 enables the opening at the axial end of the limiting channel 62 farther from the groove 5 to maintain a good shape and remain open when the inner branch stent 8 is in a natural state (i.e., the state when the outer branch stent 500 is not inserted into the inner branch stent 8 or the inner branch stent 8 is not squeezed and deformed), which is convenient for the sheath core 600 to be withdrawn, and can effectively reduce the risk of the sheath core 600 hooking the opening edge at the axial end of the inner branch stent 8 farther from the groove 5 during the withdrawal process. Exemplarily, the end support 64 includes a corrugated ring, a corrugated unit or other closed or non-closed annular support structures. Exemplarily, the radial support force of the end support 64 is less than the radial support force of the first branch stent 81 or the second branch stent 82. Exemplarily, the end support 64 extends circumferentially along the limiting channel 62 for at least one week, as Figure 28as shown; or, the length of the end support member 64 extending along the circumferential direction of the limiting channel 62 is less than the circumference of the limiting channel 62, as Figure 29 shown. Exemplarily, the shape of the end support member 64 can be designed into any suitable shape according to actual requirements, such as circular, C-shaped or crescent-shaped, etc. Exemplarily, the end support member 64 can be made of a radiopaque material, which can not only provide a supporting effect but also be radiopaque during the operation to better indicate the position of the opening at the axial end of the limiting channel 62 that is farther away from the groove 5.

[0133] In some embodiments, the channel wall at the opening at the axial end of the limiting channel 62 that is farther away from the groove 5 and / or at the distal opening at the axial end that is closer to the groove 5 is a blank end film. In this embodiment, an end support member is provided at the opening at the axial end of the limiting channel 62 that is farther away from the groove 5, and the channel wall at the opening at the axial end of the limiting channel 62 that is closer to the groove 5 is a blank end film, that is, no end support member is provided at the opening at the axial end of the limiting channel 62 that is closer to the groove 5, so as to prevent the guide wire or the outer branch stent 500 from accidentally entering the limiting channel 62 when the covered stent 100 is in the natural state.

[0134] In some embodiments, the sheath core 600 includes a Tip head 610 and a core rod 620 connected to the Tip. To make the sheath core 600 retract more smoothly and reduce the risk of the sheath core 600 hooking the opening at the axial end of the inner branch stent 8 that is farther away from the groove 5 during the retraction process of the sheath core 600, a transition portion 630 can be provided between the Tip head 610 and the core rod 620 of the sheath core 600. The maximum width of the transition portion 630 gradually decreases from the core rod 620 to the direction of the Tip head 610. Such a setting is beneficial for the smooth transition between the Tip head 610 and the core rod 620, and can make the sheath core 600 retract more smoothly from the limiting channel 62.

[0135] In some embodiments, the limiting channel 62 and the bottom film-covered section 511 are arranged at an axial interval, so that the limiting groove 512 formed by the limiting channel 62 and the bottom film-covered section 511 is arranged at an axial interval. In this way, both the limiting channel 62 and the limiting groove 512 can radially limit the sheath core 600, improving the radial limiting ability of the sheath core 600.

[0136] In some embodiments, the limiting channel 62 and the limiting structure 9 are arranged at an axial interval, so that the limiting channel 62 and the limiting structure 9 are arranged at an axial interval. In this way, both the limiting channel 62 and the limiting structure 9 can radially limit the sheath core 600, improving the radial limiting ability of the sheath core 600.

[0137] In some embodiments, the limiting structure 9 and the bottom film-covered section 511 can respectively radially limit the sheath core 600, improving the radial limiting ability of the sheath core 600.

[0138] In some embodiments, the limiting channel 62 and the bottom film covering section 511 are arranged at an axial interval, so that the limiting groove 512 formed by the limiting channel 62 and the bottom film covering section 511 is arranged at an axial interval; the limiting structure 9 and the bottom film covering section 511 can respectively perform radial limitation on the sheath core 600; thus, the limiting channel 62, the limiting groove 512 and the limiting structure 9 can all perform radial limitation on the sheath core 600, effectively improving the radial limiting ability for the sheath core 600.

[0139] It can be understood that any one of the above-mentioned bottom film covering section 511, limiting structure 9 and limiting channel 62 can be provided, or any two of the three can be provided, or all three can be provided at the same time.

[0140] Refer to Figure 30 , in some embodiments, the mesh cover 61 can be omitted. When the mesh cover 61 is omitted, after the film-covered stent 100 is implanted, since the middle section 3 where the groove 5 is located is not supported by the mesh cover 61, the narrow blood vessel lumen is likely to squeeze the middle section 3, causing the blood vessel inner wall to occupy the space of the groove 5 and resulting in blockage of the branch opening. To reduce the probability of this phenomenon occurring, a restraint assembly can be provided on the film-covered stent 100.

[0141] Exemplarily, the restraint assembly is arranged on the main body stent 10 and has a restraint state and a release state. When in the restraint state, the restraint assembly radially restrains at least one area of the middle section 3. When in the release state, the restraint assembly releases the restraint on the middle section 3. During the implantation process, after the film-covered stent 100 is released from the sheath tube, the restraint assembly is still in the restraint state, maintaining the radial restraint on at least one area of the middle section 3, so that a gap is formed between the blood vessel wall and at least part of the area of the middle section 3, which can reduce the risk of branch opening blockage and allow the guide wire and the outer branch stent 500 to smoothly enter the branch opening through this gap. After the outer branch stent 500 is implanted, the restraint on the middle section 3 is released to completely release the middle section 3.

[0142] In this embodiment, the middle main body film 11c includes a middle film 110 and a bottom film 51a. Among them, the middle film 110 is generally in the shape of an arc piece, its cross-sectional profile is generally arc-shaped, its two radial edges are respectively used as the two edges of the groove 5 in the width direction, and are respectively fixedly connected to the two edges of the bottom film 51a in the width direction. For example, the two edges of the bottom film 51a in the width direction are respectively fixedly connected to the two edges of the groove 5 in the width direction (the first edge 531 and the second edge 532 respectively) by means of sewing, gluing, etc.

[0143] The middle section 3 further includes at least one middle wave loop 310 arranged at intervals along the axis. The middle wave loop 310 is connected to the middle main body film 11c by means of stitching, bonding, etc. The middle wave loop 310 includes a plurality of waves arranged in sequence in the circumferential direction. At least a plurality of first short waves 311 and at least one first tall wave 312 (the wave height of the tall wave is greater than that of the short wave) are included in the plurality of waves. At least one first tall wave 312 straddles both sides of the edge of one width direction of the groove 5. Such a setting is beneficial to better maintaining the shape of the edge in the width direction of the groove 5 and the areas on both sides of the edge, making the stress on both sides of the edge in the width direction of the groove 5 more uniform, and not easily forming folds after implantation, thus avoiding thrombus formation. Especially when a plurality of first tall waves 312 are arranged in sequence along the axis at the edge in the width direction of the groove 5, the probability of shortening of the edge in the width direction of the groove 5 can be effectively reduced, and the risk of forming folds at this edge of the groove 5 can be further reduced. In this embodiment, the middle section 3 provides support only through a plurality of middle wave loops 310. In other embodiments, one or more of the middle wave loops 310 can be omitted and replaced by one or more arc-shaped waveform units arranged at intervals along the axis, such as Figure 1 , Figure 2 . One or more bottom supports 71 as shown in Figures 8 to 15 can be provided at the bottom 51 of the groove. For example, one or more of the first bottom support 71a, the second bottom support 71b, and the third bottom support 71c as shown in Figure 9 can be provided, or a bottom support 71 including a joint 712 as shown in FIGS. 12(A) and 12(B) can also be provided.

[0144] Referring to Figure 30 and Figure 32 , further, the middle wave loop 310 can include a short wave unit and a tall wave unit. Among them, the short wave unit includes a plurality of first short waves 311 arranged in sequence, and the tall wave unit includes a plurality of first tall waves 312 arranged in sequence. Among them, the tall wave unit extends from the first edge 531 of the groove 5 to the second edge 532, so that first tall waves 312 are provided at both edges in the width direction of the groove 5, and the first tall wave 312 straddles both sides of the edge of the groove 5 where it is located. Such a setting is beneficial to better maintaining the shape of the two edges in the width direction of the groove 5.

[0145] Referring to Figures 30 to 33, Exemplarily, the main wave loops 101 of the proximal segment 2 and the distal segment 1 include the second tallest wave 112 and the second shortest wave 111. Among them, the wave angle of the first tallest wave 312 is smaller than the wave angle of the second tallest wave 112 in the proximal segment 2 and the distal segment 1, and the first tallest wave 312 and the second tallest wave 112 are located on the same radial side of the covered stent 100. For example, they are both located on the greater curvature side (i.e., the outer side of the covered stent 100 when it bulges and bends towards the groove opening 52, the side that is stretched when bending), and the first shortest wave 311 and the second shortest wave 111 are located on the lesser curvature side (i.e., the inner side of the covered stent 100 when it bulges and bends towards the groove opening 52, the side that is compressed when bending). Since the wave angle of the first tallest wave 312 is smaller than the wave angle of the second tallest wave 112 in the proximal segment 2 and the distal segment 1, the intermediate segment 3 is more easily constrained by the constraining assembly, and the radial force after being constrained will not be too large to cause the constraining assembly to become loose, deformed, or difficult to withdraw, etc., improving the reliability of the constraint.

[0146] In some embodiments, referring to Figure 34 and Figure 36 , the covered stent 100 further includes an easily collapsible portion 320. The easily collapsible portion 320 is located at the bottom 51 of the groove. When in the constrained state, the constraining assembly constrains the easily collapsible portion 320 so that the easily collapsible portion 320 has a first dimension in the width direction of the groove 5. When in the released state, the constraining assembly releases the constraint on the easily collapsible portion 320 so that the easily collapsible portion 320 has a second dimension in the width direction of the groove 5, and the first dimension is smaller than the second dimension. In this embodiment, a plurality of easily collapsible portions 320 are arranged at intervals in the axial direction at the bottom 51 of the groove. In other embodiments, one or more easily collapsible portions 320 may be provided.

[0147] Referring to Figure 35 , exemplarily, along the width direction of the groove 5, support portions 711 are respectively provided on both sides of the easily collapsible portion 320. For example, please also refer to Figure 34, the easy-to-receive part 320 only includes a blank bottom film section 511. The middle corrugation 310 is a non-closed corrugation 310a. The non-closed corrugation 310a includes a bottom section located at the bottom of the groove 51. The bottom section is connected to the bottom film 51a by stitching, gluing or other means. The bottom section includes a corrugation opening and support parts 711 disposed on both sides of the corrugation opening. The area of the bottom of the groove 51 corresponding to the corrugation opening is provided with a blank bottom film section 511, which serves as the easy-to-receive part 320. Since the bottom film section 511 has no support structure, it can be more easily constrained when subjected to the constraining force of the constraining assembly, and the radial force after being constrained will not be too large to cause the constraining assembly to become loose, deformed or difficult to withdraw, etc., improving the reliability of the constraint. Among them, the non-closed corrugation 310a includes a first end and a second end. A corrugation opening 313 is formed between the first end and the second end. Support parts 711 are respectively disposed on both sides of the corrugation opening 313. The support part 711 includes one or more support corrugations 314 arranged in sequence and connected to each other. A support unit 715 is further disposed between the corrugation opening 313 and the support part 711 of the non-closed corrugation 310a in the figure. The support unit 715 includes a first edge corrugation 315a disposed at the first end of the non-closed corrugation 310a and a second edge corrugation 315b disposed at the second end of the non-closed corrugation 310a. The corrugation angles of the first edge corrugation 315a and the second edge corrugation 315b are smaller than the corrugation angle of the support corrugation 314 in the support part 711. With such a setting, the areas on both sides of the corrugation opening 313 can also be more easily constrained by the constraining assembly. Further, the wave rod closer to the corrugation opening 313 in the first edge corrugation 315a is denoted as the first axial support wire 7151a, and the wave rod closer to the corrugation opening 313 in the second edge corrugation 315b is denoted as the second axial support wire 7151b. The first axial support wire 7151a and the second axial support wire 7151b extend substantially along the axis (substantially extending along the axis means that the angle with the axis of the film support 100 does not exceed 10°). With such a setting, it is beneficial to reduce the risk of the first end and the second end of the non-closed corrugation 310a piercing the bottom film 51a.

[0148] Referring to Figures 34 to 36, Exemplarily, the binding assembly includes a plurality of coils 41 and binding wires 42; at least part of the coils 41 are arranged to be connected to at least one intermediate corrugation 310. When the binding wires 42 pass through the plurality of coils 41, the binding assembly is in a bound state. When the binding wires 42 are withdrawn from the plurality of coils 41, the binding assembly is in a released state. For example, at least part of the coils 41 are located at the bottom 51 of the groove and are connected to at least one non-closed corrugation 310a. For the same non-closed corrugation 310a, at least two coils 41 are provided thereon, and the at least two coils 41 are arranged in sequence along the circumferential direction of the non-closed corrugation 310a and are distributed on both sides of the easily contractible part 320 in the width direction of the groove 5. When the binding wires 42 pass through at least two coils 41 distributed on both sides of the easily contractible part 320 and the coils 41 on both sides of the easily contractible part 320 are brought closer to each other, the easily contractible part 320 is bound and its size in the width direction of the groove 5 becomes smaller. When the binding wires 42 are withdrawn from the coils 41, the binding assembly no longer binds the easily contractible part 320. The diameter of the above-mentioned coils 41 can be matched with the binding wires 42, and each coil 41 is formed by a single-strand wire or a multi-strand wire.

[0149] It can be understood that the easily contractible part 320 in this embodiment can also achieve the function of the radial limiting sheath core 600 described above. For example, referring to Figure 37 , in the bound state, the first end and the second end of the non-closed corrugation 310a bend towards the inner cavity direction of the main body bracket 10 and approach each other, and the bottom film-covered section 511 between the first end and the second end can form a limiting groove 512 that is recessed towards the direction away from the inner cavity of the main body bracket 10. The opening direction of the limiting groove 512 faces the inner cavity direction of the main body bracket 10. The sheath core 600 can be restricted radially within the limiting groove 512, and at the same time, the binding assembly makes the size of the easily contractible part 320 in the width direction of the groove 5 smaller. The size of the bottom film-covered section 511 in the width direction of the groove 5 can be set according to its specific function. For example, when the function of the seat limiting sheath core 500 is used, it can be set with reference to the above description.

[0150] In other embodiments, referring to Figure 38, the easy-to-receive part 320 includes an easy-to-receive unit, and the easy-to-receive unit may include one or more easy-to-receive waves 3211. Exemplarily, the middle wave loop 310 is a closed wave loop 310b. The closed wave loop 310b includes a bottom section located at the bottom 51 of the groove. The bottom section is connected to the bottom film 51a by stitching, gluing or other means. The bottom section includes an easy-to-receive unit and support parts 711 disposed on both sides of the easy-to-receive unit. The easy-to-receive unit includes a plurality of easy-to-receive waves 3211 arranged in sequence and connected to each other. The support parts 711 include a plurality of support waves 314 arranged in sequence and connected to each other. The wave angle of the easy-to-receive wave 3211 is smaller than the wave angle of the support wave 314, so that the easy-to-receive wave 3211 is more easily constrained by the constraining assembly. In other embodiments, the wave height of the easy-to-receive wave 3211 may also be higher than the wave height of the support wave 314, which is beneficial to better restricting the shortening of the bottom 51 of the groove. In other embodiments, the support part 711 may include only one support wave 314.

[0151] In the above embodiments, the easy-to-receive part 320 may also be any other suitable structure, and the above support part 711 may also adopt structures such as Figure 9 , Figure 11 , Figure 12(A), Figure 12(B), Figure 13 , Figure 14 the structure of the support part 711 in, or may adopt any suitable structure. As long as the bending strength of the easy-to-receive part 320 is less than the bending strength of the support part, the easy-to-receive part 320 can be more easily constrained by the constraining assembly than the support part. Among them, the bending strength can be measured by a three-point bending test. In other embodiments, the radial support force of the easy-to-receive part 320 may be less than the radial support force of the support part, that is, in the width direction of the groove 5, the support force of the easy-to-receive part 320 may be less than the support force of the support part.

[0152] The size of the above easy-to-receive part 320 in the width direction of the groove 5 may be 10% - 50% of the width of the groove 5. For example, 10%, 20%, 30%, 40%, 50%. Such a setting enables the middle wave loop 310 to provide a better support effect and is easily constrained by the constraining assembly.

[0153] It can be understood that the above easy-to-receive part 320, the limiting structure 9 and the limiting channel 62 may be provided with only any one of them, or any two of the three may be provided, or all three may be provided at the same time.

[0154] Figure 30 , Figure 31 , Figure 34 , Figure 36In this case, the first branch stent 81 is disposed within the main stent 10, and the first branch stent 81 communicates with the groove 5; the second branch stent 82 and the first branch stent 81 are disposed on one side of the axial direction of the groove 5, and the first branch stent 81 and the second branch stent 82 are spaced apart axially. Exemplarily, the second branch stent 82 and the first branch stent 81 are disposed on the side where the proximal end of the groove 5 is located, that is, both the second branch stent 82 and the first branch stent 81 are disposed on the proximal segment 2 of the main stent 10. In this embodiment, the second branch stent 82 is disposed outside the main stent 10, and the first branch stent 81 and the second branch stent 82 on one side of the axial direction of the groove 5 will not form a triangular area with the main stent 10, thus reducing the influence on the blood flow in the lumen of the main stent 10. In addition, once the second branch stent 82 is implanted into the branch vessel 200, it is beneficial for the groove 5 to be aligned with the branch vessel 200. Please refer to Figure 31 , in some embodiments, a guiding section 812 may also be formed at the distal end of the first branch stent 81, and the cross-sectional area of the guiding section 812 extends from the proximal end to the distal end in a gradually increasing manner. The distal end of the first branch stent 81 is designed as a flared guiding section 812, and the guiding section 812 can play a guiding role in the entry of the guide wire or the outer branch stent 500. It can be understood that, in other embodiments, the arrangement positions of the first branch stent 81 and the second branch stent 82 may be different from Figure 30 , Figure 31 , Figure 34 , Figure 36 as shown in.

[0155] In other embodiments, the covered stent 100 further includes a restraining assembly disposed on the proximal segment 2 and / or the distal segment 1. When the restraining assembly is in the restraining state, it can radially restrain at least one area of the proximal segment 2 and / or the distal segment 1, and when in the release state, the restraining assembly releases the restraint on the proximal segment 2 and / or the distal segment 1.

[0156] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection", "mechanical coupling", "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. The mechanical coupling or coupling of two components includes direct coupling and indirect coupling. For example, direct fixed connection, connection through a transmission mechanism, etc. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0157] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include the first and second features not being in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher level height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower level height than the second feature.

[0158] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A covered stent, characterized in that, Comprising: A main body stent, the main body stent sequentially includes a proximal segment, an intermediate segment, and a distal segment along the axial direction. A groove is formed by the side surface of the intermediate segment being recessed towards the inner cavity direction of the main body stent. The intermediate segment includes at least one intermediate wave loop, and the intermediate wave loop includes a plurality of first short waves and at least one first tall wave, wherein at least one of the first tall waves straddles both sides of the edge in one width direction of the groove. A constraint assembly is arranged on the main body stent and has a constrained state and a released state. When in the constrained state, the constraint assembly radially constrains at least one area of the intermediate segment. When in the released state, the constraint assembly releases the constraint on the intermediate segment.

2. The covered stent according to claim 1, characterized in that, The intermediate wave loop includes a short wave unit and a tall wave unit. Among them, the short wave unit includes a plurality of first short waves arranged in sequence, and the tall wave unit includes a plurality of first tall waves arranged in sequence. Among them, the tall wave unit extends from the first edge spaced in the width direction of the groove to the second edge, and there is a first tall wave in the tall wave unit that straddles both sides of the first edge, and there is also a first tall wave in the tall wave unit that straddles both sides of the second edge.

3. The covered stent according to claim 2, wherein One or more main body wave loops are provided in the proximal segment and the distal segment along the axial direction of the covered stent. The main body wave loop includes a second tall wave and a second short wave. The wave angle of the first tall wave is smaller than the wave angle of the second tall wave, and the first tall wave and the second tall wave are located on the same radial side of the covered stent.

4. The covered stent according to claim 1, wherein, The groove includes a groove bottom. An easy-to-receive portion and support portions are provided on both sides of the easy-to-receive portion along the width direction of the groove at the groove bottom. When in the constrained state, the constraint assembly constrains the easy-to-receive portion so that the easy-to-receive portion has a first dimension in the width direction of the groove. When in the released state, the constraint assembly releases the constraint on the easy-to-receive portion so that the easy-to-receive portion has a second dimension in the width direction of the groove, and the first dimension is smaller than the second dimension.

5. The covered stent according to claim 4, characterized in that, The groove bottom includes a bottom covering film. The bottom covering film includes a blank bottom covering film segment, and the bottom covering film segment is the easy-to-receive portion. The support portion is connected to the bottom covering film.

6. The covered stent according to claim 4, wherein, The intermediate wave loop is a non-closed wave loop. The non-closed wave loop includes a bottom section located at the groove bottom. The bottom section includes a wave loop opening and support portions provided on both sides of the wave loop opening. A blank bottom covering film segment is provided in the area of the groove bottom corresponding to the wave loop opening, and the bottom covering film segment is the easy-to-receive portion.

7. The covered stent according to claim 6, characterized in that, A support unit is further provided between the support portion and the wave loop opening. The support unit includes a first edge wave and a second edge wave provided on both sides of the wave loop opening. The support portion includes one or more support waves. The wave angles of the first edge wave and the second edge wave are both smaller than the wave angle of the support wave.

8. The covered stent according to claim 4, wherein The middle wave loop is a closed wave loop. The closed wave loop includes a bottom section located at the bottom of the groove. The bottom section includes an easy-to-receive unit and support parts disposed on both sides of the easy-to-receive unit. The easy-to-receive unit includes a plurality of easy-to-receive waves arranged in sequence and connected to each other. The support parts include a plurality of support waves arranged in sequence and connected to each other. The wave angle of the easy-to-receive wave is smaller than the wave angle of the support wave.

9. The covered stent according to any one of claims 4 to 8, characterized in that, The bending strength of the easy-to-receive part is less than the bending strength of the support part.

10. The covered stent according to any one of claims 1 to 8, characterized in that, The binding assembly includes a plurality of coils and binding wires; at least part of the coils are arranged to be connected to at least one of the middle wave loops. When the binding wires are threaded through the plurality of coils, the binding assembly is in a bound state. When the binding wires are withdrawn from the plurality of coils, the binding assembly is in a released state.

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