Covered stent

Abstract

This invention relates to a covered stent, comprising a main stent and an auxiliary stent. Along the axial direction of the covered stent, the main stent includes a distal covered segment, a bare stent segment, and a proximal covered segment connected sequentially. The auxiliary stent is detachably disposed within the main stent and includes a connected auxiliary body and at least one embedded branch. The distal end of the auxiliary body communicates with the distal covered segment, and the proximal end of the auxiliary body communicates with the proximal covered segment. The distal covered segment, the auxiliary body, and the proximal covered segment together define a main channel. Along the radial direction of the covered stent, a spacer is defined between the outer peripheral surface of the auxiliary body and the inner wall surface of the bare stent segment. Each embedded branch connects the main channel and the spacer. According to the covered stent of this invention, since the mesh at any position along the circumference of the bare stent segment allows blood flow, there is no problem of branch vessels being blocked due to circumferential positional deviation after the main stent is deployed.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more particularly to a covered stent. Background Technology

[0002] Aortic aneurysms and aortic dissections are serious diseases that threaten human life. Without prompt treatment, they will continue to grow, eventually rupture, causing severe complications and even death. With the increasing number of patients with hypertension, hyperlipidemia, and hyperglycemia, the incidence of aortic aneurysms and aortic dissections is also rising significantly.

[0003] Traditional open surgery for aortic aneurysms and aortic dissections is highly invasive, has a high mortality rate, long operation time, high postoperative complication rate, and high surgical difficulty. Endovascular treatment, on the other hand, is less invasive, has fewer postoperative complications, shorter operation time, and lower surgical difficulty, and has gradually become the main method for treating aortic aneurysms and aortic dissections. Endovascular treatment mainly involves implanting a covered stent in the aorta to isolate the diseased portion of the vessel outside the stent, restricting blood flow through the stent and thus protecting the vessel. Because the covered stent needs a certain length of anchorage zone for fixation to ensure proper fixation and prevent blood flow through the proximal and distal ends of the stent, when the aortic aneurysm or aortic dissection involves branch arteries, implanting a covered stent may block the branch arteries to varying degrees, or even prevent endovascular treatment, leading to surgical failure. To address this issue, a covered stent with grooves can be implanted. The grooves correspond to the branch vessels, ensuring that blood from the aorta can pass through the grooves into the branch vessels. This not only isolates the diseased part of the vessel from the covered stent but also maintains unobstructed blood flow in the branch vessels.

[0004] During stent placement, accurately locating the circumferential position of the groove is often challenging, especially with stents located at the aortic arch. Because the distal end of the sheath must traverse the curved aortic arch to reach the ascending aorta, the significant curvature of the sheath makes it difficult for the operator to transmit the rotational force applied proximally to the distal end. This makes it challenging to adjust the circumferential position of the groove by rotating the sheath. After stent deployment, if the groove is circumferentially misaligned with the branch vessels, it can obstruct blood flow to the branch vessels. Summary of the Invention

[0005] The purpose of this invention is to at least solve the problem of stent obstruction of branch vessels after deployment due to circumferential misalignment of the groove. To address the shortcomings of the prior art, a covered stent is provided.

[0006] The technical problem solved by this invention is achieved through the following technical solution:

[0007] This invention provides a covered stent, comprising a main stent and an auxiliary stent. Along the axial direction of the covered stent, the main stent includes a distal covered segment, a bare stent segment, and a proximal covered segment connected in sequence. The auxiliary stent is detachably disposed within the main stent and includes a connected auxiliary body and at least one embedded branch. The distal end of the auxiliary body communicates with the distal covered segment, and the distal end of the auxiliary body is closer to the proximal end of the covered stent than the distal end of the main stent. The proximal end of the auxiliary body communicates with the proximal covered segment. The distal covered segment, the auxiliary body, and the proximal covered segment together define a main channel. Along the radial direction of the covered stent, a space is defined between the outer peripheral surface of the auxiliary body and the inner wall surface of the bare stent segment. Each embedded branch connects the main channel and the space.

[0008] In some embodiments of the present invention, along the axial direction of the covered stent, the auxiliary body includes a distal skirt, an auxiliary covered segment, and a proximal skirt connected in sequence. The distal skirt is embedded within the distal covered segment, and the proximal skirt is embedded within the proximal covered segment. Along the radial direction of the covered stent, the space is defined between the outer peripheral surface of the auxiliary covered segment and the inner wall surface of the bare stent. The auxiliary stent includes a plurality of embedded branches, which are respectively connected to the distal skirt and / or the proximal skirt.

[0009] In some embodiments of the present invention, the auxiliary coating segment includes a top portion and a bottom portion. The proximal end of the bottom portion is connected to the proximal skirt, and the distal end of the bottom portion is connected to the distal skirt. Along the circumference of the coating support, the top portion and the bottom portion are connected end to end and enclose to form a lumen structure. Along the radial direction of the coating support, the maximum spacing between the top portion and the bare support segment is greater than the maximum spacing between the bottom portion and the bare support segment.

[0010] In some embodiments of the present invention, the proximal end of the top surface portion and the inner wall surface of the proximal skirt define a first branch opening communicating with the spacer; the auxiliary support further includes a first transition portion, the first transition portion having a trumpet-shaped structure with a gradually increasing diameter from the proximal end to the distal end, the distal end of the first transition portion being connected to the proximal end of the top surface portion and the inner wall of the proximal skirt respectively, and communicating with the first branch opening, the proximal end of the first transition portion being connected to and communicating with at least one of the embedded branches.

[0011] In some embodiments of the present invention, the distal end of the top surface portion and the inner wall surface of the distal skirt define a second branch opening communicating with the spacer; the auxiliary support further includes a second transition portion, the second transition portion having a trumpet-shaped structure with a gradually increasing diameter from the distal end to the proximal end, the proximal end of the second transition portion being connected to the distal end of the top surface portion and the inner wall of the distal skirt respectively, and communicating with the second branch opening, and the distal end of the second transition portion being connected to and communicating with at least one of the embedded branches.

[0012] In some embodiments of the present invention, at least one of the proximal skirt and the distal skirt includes a variable diameter section and a straight section whose diameter varies along the axial direction, and the outer peripheral surface of the straight section is used to fit against the inner peripheral surface of the main body support.

[0013] In some embodiments of the present invention, when the proximal skirt includes the variable diameter section; the covered support further includes a first inner skirt disposed within the proximal covered section, the first inner skirt being configured as a tapered structure with a gradually narrowing inner diameter from the distal end to the proximal end, the inner diameter of the proximal end of the first inner skirt being smaller than the outer diameter of the proximal end of the proximal skirt, and the proximal circumferential outer edge of the proximal skirt being able to abut against the inner wall surface of the first inner skirt; and / or, when the distal skirt includes the variable diameter section, the covered support further includes a second inner skirt disposed within the distal covered section, the second inner skirt being configured as a tapered structure with a gradually narrowing inner diameter from the proximal end to the distal end, the inner diameter of the distal end of the second inner skirt being smaller than the outer diameter of the distal end of the distal skirt, and the distal circumferential outer edge of the distal skirt being able to abut against the inner wall surface of the second inner skirt.

[0014] In some embodiments of the present invention, an inner wave ring is provided on the variable diameter section, and an outer wave ring is provided on the straight section. The outer wave ring is used to radially abut against the inner wall of the main support. The diameter of the outer wave ring is larger than the diameter of the inner wave ring, and the radial support force of the inner wave ring is greater than the radial support force of the outer wave ring.

[0015] In some embodiments of the present invention, the diameter of the bare stent segment is greater than the diameter of the distal covered segment and the proximal covered segment; and / or, the diameter of the auxiliary covered segment is smaller than the diameter of the distal skirt and the proximal skirt.

[0016] In some embodiments of the present invention, the bare support segment is a developing element made of developable metal wire;

[0017] And / or, at least one of the proximal skirt and the distal skirt is provided with a first developing element and a second developing element, the first developing element being located on the side of the top surface portion away from the central axis of the coating support along the radial direction of the coating support, and the second developing element being located on the side of the bottom surface portion away from the central axis of the coating support.

[0018] And / or, the proximal skirt is provided with a first developing wire, the first developing wire extends circumferentially along the proximal skirt and is located at the distal end of the proximal skirt. Along the radial direction of the coating support, the first developing wire is located on the side of the top surface portion opposite to the central axis of the coating support.

[0019] And / or, the proximal skirt is provided with a second developing filament, the second developing filament extending circumferentially along the distal skirt and located at the proximal end of the distal skirt. Along the radial direction of the coating support, the second developing filament is located on the side of the top surface portion opposite to the central axis of the coating support.

[0020] The covered stent proposed in this invention utilizes a bare stent segment to support the aortic arch and the corresponding regions of its branch vessels. A septum space for blood flow is defined between the inner wall of the bare stent segment and the outer peripheral surface of the auxiliary body. This allows blood in the septum space to flow through the mesh of the bare stent segment into the branch vessels. Since the mesh at any position along the circumference of the bare stent segment allows blood flow, there is no problem of branch vessels being obstructed due to circumferential positional deviation after the main stent is deployed. Furthermore, an embedded branch connects the main channel and the septum space, allowing blood pumped from the heart into the main channel to flow through the embedded branch into the septum space, and then through the mesh of the bare stent segment into the branch vessels, thus satisfying the need for blood distribution. Regarding blood supply to the branch vessels, since the distal end of the auxiliary stent is closer to the proximal end of the covered stent than the distal end of the main stent, the distal end of the sheath carrying the auxiliary stent does not need to reach the ascending aorta region, but only the aortic arch region. Therefore, the sheath carrying the auxiliary stent has less curvature, and the circumferential position of the auxiliary stent can be better adjusted by rotating the sheath. After the auxiliary stent is deployed, a septum space for blood flow is created between the auxiliary body and the bare stent segment. Furthermore, the embedded branches, due to their distribution connecting the main channel and the septum space, allow blood pumped by the heart to flow sequentially through the main channel, embedded branches, and septum space into the branch vessels, making it less likely to block blood flow to the branch vessels. In addition, after the main stent is implanted, it can also provide contrast enhancement, which can help to better position the internal auxiliary stent. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. Wherein:

[0022] Figure 1 This is a schematic diagram of the structure of a film-coated stent according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of a film-coated stent according to an embodiment of the present invention;

[0024] Figure 3 for Figure 2 A magnified view of part A in the middle;

[0025] Figure 4a This is a schematic diagram of the main support structure according to an embodiment of the present invention;

[0026] Figure 4b This is a schematic diagram of the main support structure according to another embodiment of the present invention;

[0027] Figure 4c This is a schematic diagram of the main support structure according to another embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the main support structure according to another embodiment of the present invention;

[0029] Figure 6a This is a schematic diagram of the structure of the auxiliary support according to the first embodiment of the present invention;

[0030] Figure 6b This is a schematic diagram of the auxiliary support structure according to the second embodiment of the present invention;

[0031] Figure 6c This is a schematic diagram of the auxiliary support structure according to the third embodiment of the present invention;

[0032] Figure 6d This is a schematic diagram of the auxiliary support structure according to the fourth embodiment of the present invention;

[0033] Figure 6e This is a schematic diagram of the auxiliary support structure according to the fifth embodiment of the present invention;

[0034] Figure 7 This is a partial structural schematic diagram of an auxiliary support according to an embodiment of the present invention;

[0035] Figure 8 This is a schematic diagram of the structure of a first bare stent, a third bare stent, and a fourth bare stent according to an embodiment of the present invention;

[0036] Figure 9 It shows Figure 8 A magnified view of part C in the middle;

[0037] Figure 10 It shows Figure 8 A magnified view of part B in the middle section;

[0038] Figure 11 This is a schematic diagram of the structure of the first bare support, the third bare support, and the fourth bare support according to another embodiment of the present invention;

[0039] Figure 12 This is a schematic diagram of the structure of the first bare stent, the third bare stent, and the fourth bare stent according to another embodiment of the present invention. Detailed Implementation

[0040] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0041] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0042] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0043] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure rotates, then an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations.

[0044] It should be noted that the terms "distal" and "proximal" are used as directional terms, which are commonly used in the field of interventional medical devices. "Distal" refers to the end furthest from the operator during the procedure, while "proximal" refers to the end closest to the operator. Axial direction refers to the direction parallel to the line connecting the center of the distal and proximal ends of the medical device; radial direction refers to the direction perpendicular to the aforementioned axial direction.

[0045] Please combine Figure 1 , Figure 2 and Figure 6a As shown, this invention proposes a covered stent, comprising a main stent 10 and an auxiliary stent 5. The main stent 10 is used to intervene in the diseased area of ​​the aorta, such as the location of the aortic arch, with the assistance of a delivery system. The auxiliary stent 5 is detachably embedded within the main stent 10. The main stent 10 and the auxiliary stent 5 together establish a channel for blood flow and isolate the vascular lesion (such as aortic aneurysm, aortic dissection, etc.) outside the covered stent, restricting blood flow from passing through the inside of the covered stent, thereby achieving the purpose of protecting the blood vessel. It should be noted that, since the auxiliary stent 5 is detachable from the main stent 10, unless otherwise specified, the shape and structure description of this invention refers to the auxiliary stent 5 being assembled within the main stent 10, and the covered stent being in a fully deployed, unrestrained state.

[0046] In detail, the main stent 10 includes a distal covered segment 11, a bare stent segment 12, and a proximal covered segment 13, which are connected sequentially along the axial direction of the covered stent. The auxiliary stent 5 includes an auxiliary body 50 and at least one embedded branch 510. The embedded branch 510 is connected to the auxiliary body 50. The distal end of the auxiliary body 50 is connected to the distal covered segment 11, and the proximal end of the auxiliary body 50 is connected to the proximal covered segment 13. The distal covered segment 11, the auxiliary body 50, and the proximal covered segment 13 are all covered lumen structures. The distal covered segment 11, the auxiliary body 50, and the proximal covered segment 13 together define the main channel. Blood pumped from the heart to the aorta enters the main channel from the distal covered segment 11 and flows out of the main channel from the proximal end of the proximal covered segment 13. The distal covered segment 11, the auxiliary body 50, and the proximal covered segment 13 together isolate the diseased area of ​​the aorta. Along the radial direction of the covered stent, a septum space is defined between the outer peripheral surface of the auxiliary body 50 and the inner wall surface of the bare stent segment 12. Each embedded branch 510 connects the main channel and the septum space. The bare stent segment 12 supports the aortic arch and the corresponding area of ​​the branch vessels on the arch. The septum space for blood flow is defined between the inner wall surface of the bare stent segment 12 and the outer peripheral surface of the auxiliary body 50, allowing blood in the septum space to flow into the branch vessels through the mesh of the bare stent segment 12. Since blood can flow through the mesh at any position along the circumference of the bare stent segment 12, there is no problem of the branch vessels being blocked due to circumferential position deviation after the main stent 10 is released. Furthermore, the embedded branch 510 connects the main channel and the septum space, allowing blood pumped into the main channel by the heart to flow into the septum space through the embedded branch 510 and then into the branch vessels through the mesh of the bare stent segment 12, thus satisfying the blood supply to the branch vessels.

[0047] When the lesion involves the aortic arch and its branch vessels in a complex situation, the embedded branch 510 is used to connect to the external stent. The branch vessels include the brachiocephalic trunk, the left common carotid artery and the left subclavian artery. After the main stent 10 and the auxiliary stent 5 are released, the external stent penetrates into the aorta through one of the three branch vessels above the aorta and enters the septal space from the outer peripheral surface of the bare stent segment 12. It is then inserted and fixed into the embedded branch 510 through the septal space and communicates with the embedded branch 510. Thus, the blood supply pathway connecting the aorta and the branch vessels is established by using the embedded branch 510 and the external stent.

[0048] Generally, to successfully insert the external stent into the embedded branch 510, it is necessary to ensure that after the auxiliary stent 5 is redeployed, the side with the embedded branch 510 faces the junction of the aorta and the branch vessels along the circumference of the aorta, i.e., the embedded branch 510 faces the greater curvature of the aortic arch. The procedure for implanting a covered stent into the aorta proposed in this invention is as follows: first, the main stent 10 is inserted into the diseased area of ​​the aortic arch, ensuring that the bare stent segment 12 of the main stent 10 covers the area where the three branch vessels of the aorta are located in the axial direction of the aorta; then, the main stent 10 is released to allow it to expand and be fixed inside the aorta. Since the bare stent segment 12 is not covered with a cladding, it has multiple pores distributed circumferentially, allowing blood from the aorta to flow into the branch vessels through these pores. Therefore, during the implantation of the main stent 10, the axial position of the bare stent segment 12 only needs to be adjusted by pushing or retracting the sheath in the axial direction to cover the area of ​​the three branch vessels above the aorta. There is no need to adjust the circumferential position of the main stent 10, thus eliminating the need to rotate the sheath. After the main stent 10 is implanted, the auxiliary stent 5 is delivered into the main stent 10 using the delivery system. The auxiliary stent 5 is aligned with the bare stent segment 12 in the radial direction of the covered stent, and then released. The auxiliary stent 5 expands within the main stent 10 and is fixed therein. Together with the distal covered segment 11, the auxiliary main body 50, and the proximal covered segment 13, a circumferentially closed lumen structure with proximal and distal openings is formed. The internal space of this lumen structure constitutes the main channel.

[0049] It should be noted that when the lesion involves branch vessels and requires the insertion of an external stent within the branch vessel, it is necessary to improve the circumferential positioning accuracy of the auxiliary stent 5 after deployment. Adjusting the circumferential position of the auxiliary stent 5 requires rotating the sheath carrying the auxiliary stent 5. Understandably, compared to the main stent 10, the axial length dimension of the auxiliary stent 5 is smaller (for example, the ratio of the axial distance between the proximal end of the auxiliary stent 5 and the proximal end of the main stent 10 to the total axial length of the proximal covered segment 13 ranges from 1 / 2 to 5 / 6, and the ratio of the axial distance between the distal end of the auxiliary stent 5 and the distal end of the main stent 10 to the total axial length of the distal covered segment 11 ranges from 1 / 3 to 2 / 3). Furthermore, the distal end of the sheath carrying the auxiliary stent 5 does not need to reach the area of ​​the ascending aorta, but only needs to reach the main aorta. The arterial arch region is suitable, therefore, the sheath carrying the auxiliary stent 5 has a smaller degree of curvature, allowing for better circumferential position adjustment of the auxiliary stent 5 by rotating the sheath. After the auxiliary stent 5 is released, a septum space for blood flow is created between the auxiliary body 50 and the bare stent segment 12. Furthermore, the embedded branches 510, due to their distribution connecting the main channel and the septum space, allow blood pumped by the heart to flow sequentially through the main channel, the embedded branches 510, and the septum space into the branch vessels, reducing the risk of obstructing blood flow to the branch vessels. In addition, after the main stent is implanted, it also provides contrast enhancement, aiding in better positioning of the internal auxiliary stent 5.

[0050] It should be noted that when the lesion involves branch vessels, the covered stent can completely isolate the aortic aneurysm area from the blood by connecting the external stent to the corresponding embedded branch 510. Furthermore, when the aortic lesion area only has stenosis and does not require blood isolation, the main stent 10 can be selectively placed without the auxiliary stent 5, thus making it suitable for various treatment scenarios.

[0051] The covered stent proposed in this invention, through the synergistic design of the embedded branch 510, the auxiliary body 50, and the bare stent segment 12, completely solves the problem of traditional covered stents blocking branch vessels due to circumferential positional deviations. Regardless of how the stent is fine-tuned during deployment, the mesh at any circumferential position of the bare stent segment 12 ensures blood flow into the branch vessels, providing stable support for blood supply to the head, neck, and upper limbs, greatly reducing the risk of serious complications such as cerebral infarction and upper limb dysfunction caused by postoperative branch vessel ischemia. The three-segment structure of the main stent 10 (distal covered segment 11, bare stent segment 12, and proximal covered segment 13), combined with the auxiliary stent 5, comprehensively and seamlessly encapsulates and isolates the aortic lesion from proximal to distal, preventing blood from impacting the lesion site and effectively preventing fatal risks such as aneurysm rupture and further tearing of aortic dissection. This creates a favorable healing environment for the diseased vessel and significantly improves the long-term survival rate of patients. Compared to traditional open surgery, it eliminates the need for thoracotomy and laparotomy, greatly reducing surgical trauma, shortening operation time, and lowering postoperative risks.

[0052] In some embodiments, such as Figure 4c As shown, the bare stent section 12 includes a plurality of bare wave coils arranged axially at intervals. The bare wave coils have an annular structure and extend along the circumferential direction of the covered stent. The bare stent section 12 also includes connecting wires that extend along the circumferential direction and are sequentially connected to each bare wave coil.

[0053] In other embodiments, such as Figure 4a As shown, the bare scaffold segment 12 includes multiple first braided filaments extending along a first direction and multiple second braided filaments extending along a second direction. The first and second braided filaments interweave to form a cylindrical structure with multiple grids. The grids are generally rhomboid, but can also be square, rectangular, or other shapes. Four intersection points are provided at the four corners of this deformable grid. Each intersection point includes an intersection formed by the overlapping of the first and second braided filaments. At this intersection point, the first and second braided filaments can move relative to each other to a certain extent (or slide), and can also be fixed together by stitching or gluing.

[0054] In other embodiments, such as Figure 4b As shown, the bare support segment 12 includes multiple bare wave rings arranged axially at intervals. Along the axial direction, any two adjacent bare wave rings form multiple connection points. Each connection point is where the peak of one bare wave ring is connected to the trough of another bare wave ring, so that the bare support segment 12 as a whole forms a cylindrical structure with multiple grids. The grids are roughly rhomboid, but can also be square, rectangular, or other shapes.

[0055] In some embodiments, please combine Figure 1 , Figure 2 as well as Figures 6a to 6eAs shown, along the axial direction of the covered stent, the auxiliary body 50 includes a distal skirt 501, an auxiliary covered segment 500, and a proximal skirt 502 connected in sequence. Specifically, the distal skirt 501 is located at the farthest end of the auxiliary body 50, has a skirt-like structure, and is embedded within the distal covered segment 11. On the one hand, the distal skirt 501 enhances the stability of the connection between the auxiliary body 50 and the distal covered segment 11, preventing them from becoming disengaged or displaced. On the other hand, the distal skirt 501 acts like a tight "seale," ensuring a smoother and more concentrated transition of blood from the distal covered segment 11 into the auxiliary body 50, improving the seal between the auxiliary body 50 and the distal covered segment 11, and reducing the probability of blood leakage at the connection between the auxiliary body 50 and the distal covered segment 11. The auxiliary covered segment 500 is located in the middle part of the auxiliary body 50, axially connecting the distal skirt 501 and the proximal skirt 502. In the radial direction, the outer peripheral surface of the auxiliary covered segment 500 is spaced from the inner wall surface of the bare stent, forming a gap space. This gap space not only creates conditions for subsequent implantation of an external stent to drain blood from branch vessels, but also isolates the lesion area and guides blood flow from the ascending aorta to the descending aorta. The proximal skirt 502 is located proximal to the auxiliary body 50 and is embedded within the proximal covered segment 13. It strengthens the connection between the auxiliary body 50 and the proximal covered segment 13, ensuring a smooth and stable flow of blood from the auxiliary body 50 to the proximal covered segment 13 and preventing problems such as blood leakage or backflow. Together with the distal skirt 501, it firmly "anchors" the auxiliary body 50 to the corresponding part of the main stent 10. Multiple embedded branches 510 are included, and their placement can be determined based on factors such as the actual distribution of branches on the aortic arch, blood supply requirements, and ease of surgical operation. For example, when aortic dissection involves the openings of branch vessels, requiring stents to be implanted in the brachiocephalic trunk, left common carotid artery, and left subclavian artery, two embedded branches 510 can be provided at the distal skirt 501, corresponding to the brachiocephalic trunk and left common carotid artery, and one embedded branch 510 can be provided at the proximal skirt 502 to correspond to the left subclavian artery. Alternatively, in some embodiments, when the aortic dissection tear and its extent do not affect the openings of branch vessels, and a covered stent can effectively isolate the lesion, restore normal blood flow channels, and ensure blood supply to branch vessels without the need for stent implantation, the number of embedded branches 510 can be set to two. One embedded branch 510 is connected to the proximal skirt 502 and used to connect the proximal end of the septal space to the main channel, and the other embedded branch 510 is connected to the distal skirt 501 and used to connect the distal end of the septal space to the main channel.

[0056] In this embodiment, the distal skirt 501 and the proximal skirt 502 are embedded in the distal covered segment 11 and the proximal covered segment 13, respectively, which greatly enhances the reliability and sealing of the connection between the auxiliary body 50 and the main stent 10. Under the influence of multiple factors such as blood flow impact, cardiac pulsation and mechanical stress generated by the patient's daily activities, it can effectively prevent the auxiliary stent 5 from shifting, deforming and leaking, ensure the long-term stable operation of the stent system and reduce the risk of stent-related complications.

[0057] In this regard, please combine Figure 1 , Figure 2 and Figure 6a As shown, the maximum diameter of the proximal skirt 502 is larger than the diameter of the auxiliary covered section 500, and the diameter of the distal skirt 501 is larger than the diameter of the auxiliary covered section 500. This arrangement increases the strength of the connection between the auxiliary body 50 and the main stent 10, while allowing the auxiliary covered section 500 to have a smaller diameter than the main stent 10. This increases the radial distance between the auxiliary covered section 500 and the bare stent section 12, which in turn increases the radial width of the septum, creating more favorable conditions for blood flow within the septum. A wider septum reduces resistance to blood flow, allowing blood to flow more smoothly through the embedded branch 510 into the septum and then through the mesh of the bare stent into the branch vessels. This reduces the probability of turbulent and eddy flow, helps maintain stable blood flow, and prevents excessive blood pooling or excessively rapid flow in local areas, thereby reducing the risk of thrombosis. Furthermore, when the auxiliary support 5 and the main support 10 are separated and in a fully extended state without constraints, the maximum outer diameter of the proximal skirt 502 can be greater than the maximum inner diameter of the proximal covered section 13, and the maximum outer diameter of the distal skirt 501 can be greater than the maximum inner diameter of the distal covered section 11, so that after the auxiliary support 5 is assembled into the main support 10, the proximal skirt 502 and the distal skirt 501 can be more firmly anchored to the main support 10.

[0058] In some embodiments, please combine Figure 1 and Figure 4aAs shown, the diameter of the bare stent segment 12 is larger than that of the distal covered segment 11 and the proximal covered segment 13. The larger diameter of the bare stent segment 12 allows it to better conform to the vessel wall of the aortic arch, enabling the main stent 10 to fit tightly against the vessel wall, providing more stable support and reducing the risk of displacement. Furthermore, since the bare stent segment 12 corresponds to the branch vessels on the aortic arch, its larger diameter helps create a larger space between the inner wall of the bare stent segment 12 and the outer peripheral surface of the auxiliary body 50, providing a wider flow channel for blood and further reducing the risk of eddies generated within the covered stent. It should also be noted that the larger diameter of the bare stent segment 12 can reduce the speed of blood flow through the space before external stent implantation, helping to reduce the impact force of blood flow on the vessel wall, especially in the diseased vessel area. Reducing blood flow shear force can prevent further damage to the vascular intima, which is beneficial in inhibiting further tearing of diseased structures such as aortic dissection or rupture of aortic aneurysms.

[0059] In some embodiments, please combine Figure 2 and Figure 6a As shown, the auxiliary covered segment 500 includes a top portion 51 and a bottom portion 52, which extend axially. The proximal end of the bottom portion 52 is connected to the proximal skirt 502, and the distal end of the bottom portion 52 is connected to the distal skirt 501. Along the circumference of the covered stent, the top portion 51 and the bottom portion 52 are connected end to end and enclose a lumen structure to ensure orderly blood flow within the auxiliary covered segment 500. After the auxiliary stent 5 is implanted into the main stent 10, the top portion 51 is positioned radially opposite the opening of the branch vessel in the aorta. Along the radial direction of the covered stent, the maximum gap between the top portion 51 and the bare stent segment 12 is greater than the maximum gap between the bottom portion 52 and the bare stent segment 12, creating a relatively spacious space between the top portion 51 and the bare stent segment 12, thus creating favorable conditions for subsequent blood flow distribution and guiding the insertion of the external stent into the embedded branch 510. From a radial perspective, the gap between the bottom portion 52 and the bare stent segment 12 is relatively small, allowing the bottom portion 52 to be closer to the bare stent segment 12. To a certain extent, this provides auxiliary support, enhances the anchoring force of the main stent 10 and the auxiliary stent 5, stabilizes the blood flow channel, and ensures that the main channel has sufficient space for blood flow.

[0060] Because there is a large gap between the top portion 51 and the bare stent segment 12, when blood flows into the gap space from the main channel, more blood will preferentially flow to the relatively spacious area around the top portion 51 to distribute blood flow more rationally. This allows blood to flow more smoothly through the area between the top portion 51 and the bare stent segment 12 into the branch vessels, ensuring sufficient blood supply to the branch vessels.

[0061] The differentiated septum design of the top portion 51 and the bottom portion 52 can better adapt to the tortuous characteristics of the aortic arch. On the lateral side of the aortic arch (greater curvature side), the larger septum of the top portion 51 can better accommodate blood flow, possibly due to factors such as vascular dilation; while on the medial side of the aortic arch (lesser curvature side), the relatively smaller septum of the bottom portion 52 helps to conform to the vessel wall and improve the adaptability of the covered stent to the vessel.

[0062] In this embodiment, please refer to Figure 2 , Figure 4a and Figure 6a As shown, the top portion 51 includes a first bare support 512 and a first covering film 51a, with the first covering film 51a covering the first bare support 512. The bottom portion 52 includes a second bare support 521 and a second covering film 522, with the second covering film 522 covering the second bare support 521. The first bare support 512 and the second bare support 521 are connected end-to-end in the circumferential direction and together form a cylindrical structure. The first covering film 51a and the second covering film 522 are connected end-to-end in the circumferential direction of the covering support, or the first covering film 51a and the second covering film 522 are an integral covering structure and are fitted over the cylindrical structure formed by the first bare support 512 and the second bare support 521. The bare support segment 12 is a cylindrical structure woven from metal wires. To achieve a maximum spacing between the top portion 51 and the bare support segment 12 in the radial direction that is greater than the maximum spacing between the bottom portion 52 and the bare support segment 12, the top portion 51 and the bottom portion 52 can be configured in various structural forms. For example, in some embodiments, both the top portion 51 and the bottom portion 52 are arc-shaped structures, and the curvature of the top portion 51 is smaller than that of the bottom portion 52. This makes the distance between the top portion 51 and the central axis of the covered support less than the distance between the bottom portion 52 and the central axis of the covered support. In other words, the outline of the top portion 51 is radially closer to the central axis of the covered support than the bottom portion 52. This makes the top portion 51 radially farther away from the inner wall of the bare support segment 12 than the bottom portion 52, thereby creating a larger gap between the top portion 51 and the bare support segment 12. In other embodiments, the bottom portion 52 is an arc-shaped structure and the top portion 51 is a planar structure, such that the outline of the top portion 51 is closer to the central axis of the covered support in the radial direction than the bottom portion 52. That is, the top portion 51 is further away from the inner wall of the bare support segment 12 in the radial direction than the bottom portion 52, thereby creating a larger gap between the top portion 51 and the bare support segment 12.

[0063] In some embodiments, such as Figure 6b As shown, the second bare support 521 includes a plurality of bare wave coils arranged axially at intervals. The bare wave coils have an annular structure and extend along the circumferential direction of the covered support. The second bare support 521 also includes connecting wires that extend along the circumferential direction and are sequentially connected to each bare wave coil.

[0064] In other embodiments, such as Figure 6a As shown, the second bare support 521 includes multiple bare wave rings arranged axially at intervals. Along the axial direction, any two adjacent bare wave rings form multiple connection points. Each connection point is where the crest of one bare wave ring is connected to the trough of another bare wave ring, so that the second bare support 521 as a whole forms a cylindrical structure with multiple grids. The grids are roughly rhomboid, but can also be square, rectangular, or other shapes.

[0065] In this embodiment, the first coating 51a and the second coating 522 can be applied to the inner and / or outer surfaces of the first bare support 512 and the second bare support 521 by methods such as sewing, bonding, or heat fusion.

[0066] Furthermore, please combine Figure 2 , Figure 6c and Figure 6e As shown, the proximal end of the top surface portion 51 and the inner wall of the proximal skirt 502 define a first branch opening (not shown in the figure) that communicates with the spacer. The plurality of embedded branches 510 include a first embedded branch 5101. The first embedded branch 5101 includes a first main body portion 51011 and a first transition portion 51012. The first transition portion 51012 has a trumpet-shaped structure with a diameter that gradually increases from the proximal end to the distal end. The first main body portion 51011 has a cylindrical structure. The distal end of the first transition portion 51012 is connected to the proximal end of the top surface portion 51 and the inner wall of the proximal skirt 502, respectively, and communicates with the first branch opening. The proximal end of the first transition portion 51012 is connected to and communicates with the distal end of the first main body portion 51011. The proximal end of the first main body portion 51011 communicates with the main channel.

[0067] After the heart pumps blood into the main channel of the covered stent, the blood flows through the first main body 51011 into the first transition section 51012. Because the first transition section 51012 is funnel-shaped, with its diameter gradually increasing from proximal to distal, the blood flow velocity is adjusted appropriately according to the change in diameter as the blood flows through it, facilitating smoother flow to the first branch orifice and then into the septal space. Then, the blood flows through the mesh of the bare stent segment 12 into the branch vessels, thus providing blood supply to the branch vessels. When the lesion involves the left subclavian artery, the structure of the first transition section 51012 also guides the insertion of an external stent from the left subclavian artery into the aorta, allowing for a smoother connection between the external stent and the first main body 51011.

[0068] In some embodiments, please combine Figure 2 , Figure 6a , Figure 6c and Figure 7As shown, the first embedded branch 5101 includes a third bare stent 511b and a third covering 511d. The third covering 511d covers the third bare stent 511b. The third bare stent 511b is connected to the proximal end of the first bare stent 512, and the third covering 511d is connected to the proximal end of the first covering 51a. This makes the first embedded branch 5101 and the auxiliary covering segment 500 an integral structure, which can effectively enhance the stability of the entire covered stent. Under the influence of factors such as blood flow impact, cardiac pulsation, and mechanical stress generated by the patient's daily activities, the connections between the first embedded branch 5101, the auxiliary covering segment 500, and the external stent embedded in the first embedded branch 5101 are tight, making displacement and deformation less likely. This ensures the long-term stable operation of the stent system and reduces the risk of related complications.

[0069] Furthermore, the distal end of the top surface portion 51 and the inner wall of the distal skirt 501 define a second branch opening (not shown in the figure) that communicates with the spacer space; the plurality of embedded branches 510 include a second embedded branch 5102, the second embedded branch 5102 includes a second main body portion 51021 and a second transition portion 51022, the second transition portion 51022 has a trumpet-shaped structure with a diameter that gradually increases from the distal end to the proximal end, the second main body portion 51021 has a cylindrical structure, the proximal end of the second transition portion 51022 is connected to the distal end of the top surface portion 51 and the inner wall of the distal skirt 501 respectively, and communicates with the second branch opening, the distal end of the second transition portion 51022 is connected to and communicates with the proximal end of the second main body portion 51021, and the distal end of the second main body portion 51021 communicates with the main channel.

[0070] After the heart pumps blood into the main channel of the covered stent, the blood flows through the second main body 51021 into the second transition section 51022. Because the second transition section 51022 is funnel-shaped, with its diameter gradually increasing from distal to proximal, the blood flow velocity is adjusted appropriately according to the change in tube diameter as the blood flows through it, facilitating smoother flow to the second branch orifice and into the septal space. Then, the blood flows through the mesh of the bare stent segment 12 into the branch vessels, thus providing blood supply to the branch vessels. When the lesion involves the brachiocephalic trunk or the left common carotid artery, the second main body 51021 is configured as a single-tube structure. The structure of the second transition section 51022 also guides the insertion of an external stent from the brachiocephalic trunk or left common carotid artery into the aorta, allowing for smoother connection between the external stent and the second main body 51021. When the lesion involves the brachiocephalic trunk and the left common carotid artery, the second main body 51021 is configured as a parallel double-tube structure, that is, the second main body 51021 includes a first lumen 510211 and a second lumen 510212 arranged in parallel (see...). Figure 6c and Figure 6eThe second transition section 51022 guides two external stents that were inserted from the brachiocephalic trunk and the left common carotid artery, so that each external stent can be smoothly inserted into a tube structure of the second main body 51021. That is, the external stent inserted from the brachiocephalic trunk is inserted and fixed into the first lumen 510211, and the external stent inserted from the left common carotid artery is inserted and fixed into the second lumen 510212.

[0071] In some embodiments, please combine Figure 2 and Figure 7 As shown, the second embedded branch 5102 includes a fourth bare stent 511a and a fourth covering 511c. The fourth covering 511c covers the fourth bare stent 511a. The fourth bare stent 511a is connected to the distal end of the first bare stent 512, and the fourth covering 511c is connected to the distal end of the first covering 51a. This makes the second embedded branch 5102 and the auxiliary covering segment 500 an integral structure, which can effectively enhance the stability of the entire covered stent. Under the influence of factors such as blood flow impact, cardiac pulsation, and mechanical stress generated by the patient's daily activities, the connections between the second embedded branch 5102, the auxiliary covering segment 500, and the external stent embedded in the second embedded branch 5102 are tight, making displacement and deformation less likely. This ensures the long-term stable operation of the stent system and reduces the risk of related complications.

[0072] In some embodiments, please combine Figure 2 and Figure 6a As shown, both the proximal skirt 502 and the distal skirt 501 are formed by a skirt covering circumferentially. At least one of the proximal skirt 502 and the distal skirt 501 includes a variable-diameter section whose diameter changes along the axial direction, and at least one of the proximal skirt 502 and the distal skirt 501 also includes a straight section. The variable-diameter section is connected to the auxiliary body 50 at one end, and the other end is connected to the straight section. The outer circumferential surface of the straight section is in contact with the inner circumferential surface of the main support 10, increasing the contact area between the proximal skirt 502 or the distal skirt 501 and the main support 10, making the contact between the proximal skirt 502 or the distal skirt 501 and the main support 10 tighter. During blood flow, the tight fit can effectively prevent blood leakage from the connection, thereby improving the sealing effect of the entire covered stent, ensuring that blood flows along the expected channel, and reducing the risk of blood leakage.

[0073] The variable-diameter section is equipped with an inner corrugated ring 5010, and the straight section is equipped with an outer corrugated ring 5020. The shape of the inner corrugated ring 5010 is adapted to the shape of the variable-diameter section, and the shape of the outer corrugated ring 5020 is adapted to the shape of the straight section. The outer corrugated ring 5020 abuts against the inner wall of the main support 10. The diameter of the outer corrugated ring 5020 is larger than that of the inner corrugated ring 5010, and the radial support force of the inner corrugated ring 5010 is greater than that of the outer corrugated ring 5020. When the inner corrugated ring 5010 and the outer corrugated ring 5020 are made of the same material, the wire diameter of the inner corrugated ring 5010 is larger than that of the outer corrugated ring 5020, that is, the wire diameter of the inner corrugated ring 5010 is thicker, giving it better radial support force. The wire diameter of the outer corrugated ring 5020 is thinner and more flexible, allowing it to better fit against the inner wall of the main support 10, thus improving the sealing effect. When the inner wave ring 5010 and the outer wave ring 5020 are made of different materials, the wire diameter of the inner wave ring 5010 can also be set to be equal to that of the outer wave ring 5020. That is, the rigidity of the inner wave ring 5010 material is better than that of the outer wave ring 5020 material, which makes the radial support force of the inner wave ring 5010 better. The outer wave ring 5020 is more flexible, which allows the outer wave ring 5020 to fit better against the inner wall of the main support 10 and improve the sealing effect.

[0074] In one exemplary embodiment, please refer to Figure 2 , Figure 6a and Figure 6b As shown, both the near-end skirt 502 and the far-end skirt 501 are provided with a variable diameter section and a straight section.

[0075] Specifically, the proximal skirt 502 includes a first variable diameter section 5021 and a first straight section 5022. Along the axial direction, from the proximal end to the distal end, the diameter of the first variable diameter section 5021 gradually decreases, and the first straight section 5022 is connected to the proximal end of the first variable diameter section 5021. The distal skirt 501 includes a second variable diameter section inner wave and a second straight section 5012. Along the axial direction, from the proximal end to the distal end, the diameter of the second variable diameter section 5011 gradually increases, and the second straight section 5012 is connected to the distal end of the second variable diameter section 5011. This configuration ensures that the opening of the proximal skirt 502 faces proximally, with its proximal edge suspended, while the opening of the distal skirt 501 faces distally, with its distal edge suspended. Since blood pumped from the heart to the main channel flows from distal to proximal, this blood flow allows the outer edges of the proximal and distal skirts 502 and 501 to better adhere to the vessel wall and resist blood flow impact, resulting in a better seal. This prevents blood from entering the space between the top surface 51 and the main stent 10 through the gap between the skirt and the main stent 10. Therefore, in cases of aortic dissection or aneurysm involving branch vessels, the seal between the proximal and distal skirts 502 and the main stent 10 isolates the lesion area. It should also be noted that the distal opening of the distal skirt 501 facing distally also effectively guides blood into the second embedded branch 5102, ensuring sufficient blood supply to the branch vessels and facilitating the retraction of the stent 5. In another exemplary embodiment, please refer to... Figure 2 and Figure 6c As shown, both the near-end skirt 502 and the far-end skirt 501 are provided with a variable diameter section and a straight section.

[0076] Specifically, the proximal skirt 502 includes a first variable-diameter section 5021 and a first straight section 5022. Along the axial direction, from the proximal end to the distal end, the diameter of the first variable-diameter section 5021 gradually increases, and the first straight section 5022 is connected to the distal end of the first variable-diameter section 5021. The distal skirt 501 includes a second variable-diameter section 5011 and a second straight section 5012. Along the axial direction, from the proximal end to the distal end, the diameter of the second variable-diameter section 5011 gradually decreases, and the second straight section 5012 is connected to the proximal end of the second variable-diameter section 5011. This configuration ensures that the opening of the proximal skirt 502 faces the distal end, and the distal edge of the proximal skirt 502 is suspended, allowing the guidewire to better pass through the opening of the proximal skirt 502 and enter the first embedded branch 5101, which is beneficial for the sheath retraction of the auxiliary stent 5 and guidewire selection. The distal skirt 501 opening faces the proximal end, and the proximal edge of the distal skirt 501 is suspended, which allows the guidewire to better pass through the opening of the distal skirt 501 into the second embedded branch 5102, which is beneficial for the sheath retraction of the auxiliary stent 5 and the selection of the guidewire, and also facilitates the sheath retraction of the auxiliary stent 5.

[0077] In another exemplary embodiment, it can be Figure 6a The far-end skirt 501 and Figure 6cThe proximal skirt 502 is used in combination, meaning the distal skirt 501 includes a second variable diameter section 5011 and a second straight section 5012. Along the axial direction, from the proximal end to the distal end, the diameter of the second variable diameter section 5011 gradually increases, and the second straight section 5012 is connected to the distal end of the second variable diameter section 5011. The opening of the distal skirt 501 faces the distal end, and the distal edge of the distal skirt 501 is suspended. The proximal skirt 502 includes a first variable diameter section 5021 and a first straight section 5022. Along the axial direction, from the proximal end to the distal end, the diameter of the first variable diameter section 5021 gradually increases, and the first straight section 5022 is connected to the distal end of the first variable diameter section 5021. The opening of the proximal skirt 502 faces the distal end, and the distal edge of the proximal skirt 502 is suspended. This configuration combines the advantages of both.

[0078] In another exemplary embodiment, please refer to Figure 2 and Figure 6d As shown, the auxiliary support 5 can also be provided with two proximal skirts 502 and two distal skirts 501.

[0079] Specifically, two proximal skirts 502 are connected sequentially along the axial direction, and the openings of the two proximal skirts 502 face opposite directions. The proximal skirt 502 located further distally has its opening facing distally, while the proximal skirt 502 located closer to the proximal end has its opening facing proximally. This design has several advantages: First, the two proximal skirts 502 increase the seal between the auxiliary stent 5 and the proximal covered segment 13 of the main stent 10, preventing blood leakage. Second, the proximal skirt 502 located closer to the proximal end has its opening facing proximally, which can better guide blood into the first embedded branch 5101, ensuring that the branch vessel receives sufficient blood supply. Third, the proximal skirt 502 located further distally has its opening facing distally, which facilitates the guidewire to pass better through the opening of the proximal skirt 502 into the first embedded branch 5101.

[0080] Two distal skirts 501 are connected sequentially along the axial direction, and the openings of the two distal skirts 501 face opposite directions. The distal skirt 501 located further distally has its opening facing distally, while the distal skirt 501 located closer to the main stent has its opening facing proximally. This design has several advantages: First, the two distal skirts 501 increase the seal between the auxiliary stent 5 and the proximal covered segment 13 of the main stent 10, preventing blood leakage. Second, the proximal opening of the distal skirt 501 located closer to the main stent facilitates better guidance of the guidewire through the opening of the distal skirt 501 into the second embedded branch 5102, which is beneficial for the sheathing of the auxiliary stent 5 and guidewire insertion. Third, the distal opening of the distal skirt 501 located further distally guides blood into the second embedded branch 5102, ensuring that the branch vessel receives sufficient blood supply.

[0081] In another exemplary embodiment, please refer to Figure 2 and Figure 6e As shown, both the near-end skirt 502 and the far-end skirt 501 are provided with a variable diameter section and a straight section.

[0082] Specifically, the proximal skirt 502 includes a first variable diameter section 5021 and a first straight section 5022. Along the axial direction, from the proximal end to the distal end, the diameter of the first variable diameter section 5021 gradually increases. The first straight section 5022 is fitted outside the first variable diameter section 5021, so that the outer periphery of the first variable diameter section 5021 is connected to the inner wall surface of the first straight section 5022. That is, the first variable diameter section 5021 is located inside the first straight section 5022, so that the proximal skirt 502 is located at the proximal and distal ends. The proximal skirt 502 has several advantages, including: firstly, it resists blood flow impact, allowing the outer edge of the proximal skirt 502 to better adhere to the wall, resulting in a better seal and preventing blood leakage through the gap between the skirt and the main stent; secondly, it can better guide blood into the first embedded branch 5101, ensuring that the branch vessels receive sufficient blood supply; and thirdly, it facilitates the guidance of the guidewire to pass better through the opening of the proximal skirt 502 into the first embedded branch 5101.

[0083] The distal skirt 501 includes a second variable diameter section 5011 and a second straight section 5012. Along the axial direction, from the distal end to the proximal end, the diameter of the second variable diameter section 5011 gradually increases. The second straight section 5012 is fitted over the second variable diameter section 5011, such that the outer periphery of the second variable diameter section 5011 is connected to the inner wall surface of the second straight section 5012. That is, the second variable diameter section 5011 is located inside the second straight section 5012, ensuring that the distal skirt 501 is present at both the proximal and distal ends. The opening creates several advantages for the distal skirt 501: First, it resists blood flow impact, allowing the outer edge of the distal skirt 501 to better adhere to the wall, resulting in a better seal and preventing blood leakage through the gap between the skirt and the main stent. Second, it can better guide blood into the second embedded branch 5102, ensuring that the branch vessels receive sufficient blood supply. Third, it facilitates the guidance of the guidewire to pass better through the opening of the proximal skirt 502 into the second embedded branch 5102.

[0084] In some embodiments, please combine Figure 2 , Figure 3 , Figure 5 and Figure 6aAs shown, when the proximal skirt 502 includes a variable diameter section, the covered stent also includes a first inner skirt 70 disposed within the proximal covered section 13. The first inner skirt 70 includes a tubular first connecting section 71 and a tubular first necked section 72. The outer peripheral surface of the first connecting section 71 is attached to and connected to the inner wall surface of the proximal covered section 13. The distal end of the first connecting section 71 is connected to the distal end of the first necked section 72, and the two can be an integral structure. The first necked section 72 is configured as a narrowing structure with a gradually decreasing inner diameter from the distal end to the proximal end, so that a gap is formed in the radial direction between the proximal end of the first necked section 72 and the inner wall of the proximal covered section 13 and the first connecting section 71, so that it can adaptably undergo a certain degree of deformation. The inner diameter of the proximal end of the first inner skirt 70 is smaller than the outer diameter of the proximal end of the proximal skirt 502. The outer edge of the proximal circumferential end of the proximal skirt 502 can abut against the inner wall surface of the first necking segment 72. This arrangement allows the first inner skirt 70 to block and seal the gap between the outer circumferential surface of the proximal skirt 502 and the inner wall surface of the proximal covered segment 13 in the circumferential direction. The first connecting segment 71 and the first necking segment 72 block blood flow, making it difficult for blood from the main stent to enter the gap between the inner wall surface of the proximal skirt 502 and the proximal covered segment 13, thereby improving the sealing effect.

[0085] Furthermore, when the distal skirt 501 includes a variable diameter section, the covered support also includes a second inner skirt 80 disposed within the distal covered section 11. The second inner skirt 80 includes a tubular second connecting section 81 and a tubular second necked section 82. The outer peripheral surface of the second connecting section 81 is attached to and connected to the inner wall surface of the distal covered section 11. The proximal end of the second connecting section 81 is connected to the proximal end of the second necked section 82, and the two can be an integral structure. The second necked section 82 is configured as a constricted structure with a gradually narrowing inner diameter from the proximal end to the distal end, so that a radial gap is formed between the distal end of the second necked section 82 and the inner wall of the distal covered section 11 and the second connecting section 81, allowing it to adaptably undergo a certain degree of deformation. The inner diameter of the distal end of the second inner skirt 80 is smaller than the outer diameter of the distal end of the distal skirt 501, and the circumferential outer edge of the distal end of the distal skirt 501 can abut against the inner wall surface of the second necked section 82. This configuration allows the second inner skirt 80 to block and seal the gap between the outer peripheral surface of the distal skirt 501 and the inner wall surface of the distal covered segment 11 in the circumferential direction. The second connecting segment 81 and the second necking segment 82 block blood flow, making it difficult for blood from the main stent to enter the gap between the distal skirt 501 and the inner wall surface of the distal covered segment 11, thereby improving the sealing effect.

[0086] It should also be noted that by setting the first inner skirt 70 and the second inner skirt 80 and abutting against the proximal and distal ends of the auxiliary support 5 respectively, the first inner skirt 70 and the second inner skirt 80 are also used to limit the relative position of the auxiliary support 5 with respect to the main support 10 in the axial direction and prevent the auxiliary support 5 from moving relative to the main support 10 in the axial direction.

[0087] In some embodiments, the small curved side of the main support 10 is provided with a structure (not shown in the figure) that protrudes toward the large curved side of the main support 10, so as to be embedded in the radial recess formed by the bottom portion 52 of the auxiliary support 5 together with the proximal skirt 502 and the distal skirt 501, thereby restricting the axial movement of the auxiliary support 5 relative to the main support 10.

[0088] In some embodiments, such as Figure 2 As shown, the bare stent segment 12 is a radiopaque element made of radiopaque metal wire. This metal wire has an inner core and an outer layer. The inner core is made of radiopaque material, while the outer layer is a shape memory metal such as nickel-titanium. This gives the bare stent segment 12 good elasticity and shape memory properties. During the implantation of the main stent 10, the bare stent segment 12 can adaptively adjust its shape according to the morphology of the blood vessel, ensuring that the bare stent segment 12 fits tightly against the vessel wall and maintains a stable support state post-operatively. Radiopaque imaging of the bare stent segment 12 of the main stent can preliminarily determine the location of branch vessels and identify the major and minor bends, thus assisting in the circumferential positioning of the auxiliary stent 5. In other embodiments, a ring of radiopaque elements can be provided at both ends of the bare stent segment 12. The radiopaque elements can present a discrete distribution, such as a series of spaced bright spots, which can accurately mark the positions of both ends of the bare stent segment 12 on the image; or they can be a ring of radiopaque wire, forming a complete and continuous halo, more prominently displaying the end contour of the bare stent segment 12.

[0089] In some embodiments, please combine Figure 2 and Figure 6a As shown, at least one of the proximal skirt 502 and the distal skirt 501 is provided with a first imaging element 91 and a second imaging element 92. Along the radial direction of the covered stent, the first imaging element 91 is located on the side of the top portion 51 opposite to the central axis of the covered stent, and is used to indicate the greater curvature side, i.e., the side facing the branch vessel. The second imaging element 92 is located on the side of the bottom portion 52 opposite to the central axis of the covered stent, and is used to indicate the lesser curvature side. The first imaging element 91 and the second imaging element 92 are used to assist in imaging to adjust the circumferential position of the auxiliary stent 5 during implantation. The first imaging element 91 and the second imaging element 92 have different shapes and structures to facilitate the operator in distinguishing the circumferential position of the auxiliary stent 5. For example, the first imaging element 91 can be set in a figure-eight shape, and the second imaging element 92 can be set in an O shape.

[0090] In some embodiments, the proximal skirt 502 is provided with a first developing wire 93, which extends circumferentially along the proximal skirt 502 and is located at the distal end of the proximal skirt 502. Along the radial direction of the coating support, the first developing wire 93 is located on the side of the top surface portion 51 opposite to the central axis of the coating support, thereby indicating the location of the opening of the first branch port. In other embodiments, the first developing wire 93 may also be located at other positions of the first branch port.

[0091] A second developing wire 94 is provided on the proximal skirt 502. The second developing wire 94 extends circumferentially along the distal skirt 501 and is located at the proximal end of the distal skirt 501. Along the radial direction of the coating support, the second developing wire 94 is located on the side of the top surface portion 51 opposite to the central axis of the coating support, thereby using the first developing wire 93 to indicate the location of the opening of the second branch port. In other embodiments, the second developing wire 94 may also be provided at other locations of the second branch port.

[0092] Understandably, in some embodiments, the auxiliary stent 5 may simultaneously be equipped with a first imaging element 91, a second imaging element 92, a first imaging wire 93, and a second imaging wire 94, thereby utilizing multiple imaging methods to comprehensively determine the axial position of the auxiliary stent 5. This allows the surgeon to obtain key positional information in real time and intuitively, precisely adjust the circumferential angle of the auxiliary stent 5, ensure that the embedded branch 510 accurately connects to the branch vessel, reduce the risk of surgical failure due to inaccurate positioning, and improve the success rate of the surgery. During the operation, the surgeon does not need to repeatedly probe or guess the stent position based on experience, reducing uncertainties during the surgery. Directly operating based on the clear information provided by the imaging of the bare stent segment 12 allows for rapid and accurate implantation of the auxiliary stent 5, shortening the operation time and reducing surgical trauma and anesthesia risks for the patient.

[0093] In some embodiments, please refer to Figure 7 , Figure 8 and Figure 9The embedded branch includes an end support piece and at least one buffer portion, which is located at one end of the end support piece 511 along the axial direction. For example, in this embodiment, the multiple embedded branches include a first embedded branch and a second embedded branch, a third bare bracket and a fourth bare bracket. The third bare bracket and the fourth bare bracket have the same structure. Both radial edges of the fourth bare bracket 511a and the third bare bracket 511b include a buffer portion 560. In other embodiments, one or more buffer portions 560 may be provided. Since the buffer portion 560 is close to the axial edges of the top surface portion 51 in the axial direction, when the top surface portion 51 is subjected to axial pressure, the buffer portion 560 is first subjected to the force and deforms and moves, instead of immediately transmitting the force to the waveform unit, thus playing a certain buffering role. This can better maintain the overall shape of the end support piece 511, prevent obstruction of the branch opening, and facilitate the formation of a trapezoidal structure near the branch opening area of ​​the end support piece 511. In other embodiments, the above-mentioned buffer portion 560 may be omitted.

[0094] For example, please refer to Figure 7 , Figure 8 and Figure 9 As shown, the end support piece 511 includes a support portion 540, and the support portion 540 includes waveform units. Both the proximal support piece 511a and the third bare support 511b include two waveform units. In other embodiments, the end support piece 511 may include one or more waveform units. Each waveform unit includes multiple waves, and each wave includes a vertex and a wave rod connected to the vertex. In this embodiment, the vertex connected to the proximal end of the wave rod in the proximal support piece 511a is designated as a wave crest, and the vertex connected to the distal end of the wave rod is designated as a wave trough; similarly, the vertex connected to the proximal end of the wave rod in the third bare support 511b is designated as a wave trough, and the vertex connected to the distal end of the wave rod is designated as a wave crest.

[0095] In this embodiment, the proximal support piece 511a includes overlapping first and second waveform units. The first waveform unit includes two high waves connected radially in sequence, denoted as first high wave 541 and second high wave 542, respectively. The second waveform unit includes two high waves and one low wave, denoted as third high wave 543, fourth high wave 544, and first low wave 551, respectively. The first high wave 541 and third high wave 543 extend from the top surface portion 51 to the first branch opening of the second embedded branch 5102, and then continue to extend towards the proximal end of the second embedded branch 5102, connecting with the first lumen 510211 (see [link to previous section]). Figure 6c and Figure 7The peaks of the first high wave 541 and the third high wave 543 are both located between the proximal and distal ends of the second embedded branch 5102. Furthermore, the first high wave 541 and the third high wave 543 partially overlap radially; for example, adjacent radially adjacent wave rods of the first high wave 541 and the third high wave 543 intersect to form an intersection point. The second high wave 542 and the fourth high wave 544 extend from the top surface portion 51 to the first branch opening of the second embedded branch 5102, and then continue towards the proximal end of the second embedded branch 5102, connecting with the second lumen 510212 (see [link to documentation]). Figure 6c and Figure 7 The peaks of the second high wave 542 and the fourth high wave 544 are both located between the proximal and distal ends of the second embedded branch 5102. The second high wave 542 and the fourth high wave 544 partially overlap in the radial direction; for example, adjacent wave rods of the second high wave 542 and the fourth high wave 544 intersect to form an intersection point.

[0096] The first low wave 551 is located on the top surface portion 51 and does not extend outward beyond the edge of the top surface portion 51. The first low wave 551 is radially connected to the third high wave 543 and the fourth high wave 544, respectively. The first low wave 551 also partially overlaps with the first high wave 541 and the second high wave 542, respectively. For example, the left wave rod of the first high wave 541 overlaps with the right wave rod of the third high wave 543 to form an intersection point; the right wave rod of the first high wave 541 overlaps with the left wave rod of the first low wave 551 to form an intersection point; the left wave rod of the second high wave 542 overlaps with the right wave rod of the first low wave 551 to form an intersection point; and the right wave rod of the second high wave 542 overlaps with the left wave rod of the fourth high wave 544 to form an intersection point. The crest of the first low wave 551 is located on the top surface portion 51, and the crests of the first high wave 541 and the third high wave 543 are located on one radial side of the crest of the first low wave 551, while the crests of the second high wave 542 and the fourth high wave 544 are located on the other radial side of the crest of the first low wave 551.

[0097] In this embodiment, please refer to Figure 7 , Figure 8 , Figure 9 and Figure 10As shown, the proximal support piece 511a includes overlapping third and fourth waveform units. The third waveform unit includes two radially connected high waves, designated as the fifth high wave 545 and the sixth high wave 546, respectively. The fourth waveform unit includes three low waves, designated as the second low wave 552, the third low wave 553, and the fourth low wave 554, respectively. The fifth high wave 545 and the sixth high wave 546 extend from the top surface portion 51 to the first branch opening of the first embedded branch 5101, and then continue towards the proximal end of the first embedded branch 5101, connecting with the first main body portion 51011. The crests of both the fifth high wave 545 and the sixth high wave 546 are located between the proximal and distal ends of the first embedded branch 5101. Furthermore, the fifth high wave 545 and the sixth high wave 546 partially overlap radially; for example, adjacent wave rods of the fifth high wave 545 and the sixth high wave 546 intersect to form an intersection point. The second low-profile wave 552, the third low-profile wave 553, and the fourth low-profile wave 554 are all located on the top surface portion 51, without extending outward beyond the edge of the top surface portion 51. The radial sides of the second low-profile wave 552 connect to the third low-profile wave 553 and the fourth low-profile wave 554, respectively, and the radial sides of the second low-profile wave 552 also partially overlap with the fifth high-profile wave 545 and the sixth high-profile wave 546, respectively. The crests of the second low-profile wave 552, the third low-profile wave 553, and the fourth low-profile wave 554 are all located on the top surface portion 51, with the crest of the second low-profile wave 552 located between the fifth high-profile wave 545 and the sixth high-profile wave 546. The crests of the third low-profile wave 553 and the fourth low-profile wave 554 are respectively located on the radial sides of the crests of the fifth high-profile wave 545 and the sixth high-profile wave 546. The arrangement of the fourth waveform unit is beneficial to further improve the radial support capacity of the third bare support 511b, and can better maintain the shape of the junction between the top surface portion 51 and the first branch opening of the first embedded branch 5101.

[0098] The aforementioned second low-profile wave 552 is positioned opposite to the first branch opening of the first embedded branch 5101. For example, the crest of the second low-profile wave 552 is axially opposite to the first branch opening, and the crest of the second low-profile wave 552 may be located approximately in the same radial region as the first branch opening. When the top surface portion 51 is subjected to radial compression, the portion of the first covering 51a connected to the second low-profile wave 552 will be concave downward to a certain extent following the lower edge of the first branch opening. This prevents excessive blank covering between the fifth high-profile wave 545 and the sixth high-profile wave 546 from causing the guidewire and external branch stent 300 to bulge and block their entry into the first branch opening under the impact of blood in the inner cavity of the main stent 10. In other embodiments, the aforementioned second low-profile wave 552 may be omitted, and the fourth waveform unit may also be omitted.

[0099] The buffer section 560 includes a buffer apex 561 and a buffer rod 562 and a connecting rod 563 connecting the buffer apex 561. The buffer rod 562 is connected to the axial end of one of the waveform units of the end support plate 511, and the connecting rod 563 is connected to the axial end of the other waveform unit of the end support plate 511. The buffer apex 561 is closer to the radial edge of the end support plate 511 than the crest of the support portion 540 of the end support plate 511 it is located at. The buffer rod 562 is located at the axial edge of the end support plate 511. The buffer rod 562 is closer to the axial edge of the end support plate 511 than the connecting rod 563 and the wave bar of the support portion 540 of the end support plate 511 it is located at. That is, the crest of the buffer section 560 is closer to the axial edge of the top surface portion 51 than the crest of the waveform unit of the end support plate 511 it is located at, and the buffer rod 562 is closer to the radial edge of the top surface portion 51 than the connecting rod 563 and the wave bar of the waveform unit of the end support plate 511 it is located at. The aforementioned buffer rod 562 can be used to connect with the first membrane 51a at this location, and can preferentially deform to buffer the radial force when subjected to radial force. The force that cannot be buffered is then transmitted to the connecting rod 563, whereby the connecting rod 563 moves to further buffer the radial force. In this embodiment, the buffer rod 562 is approximately parallel to the radial edge of the top surface portion 51, which facilitates uniform radial force distribution and enables more sensitive and efficient buffering. In other embodiments, the buffer rod 562 can be angled, for example, forming an acute angle with the radial edge of the top surface portion 51.

[0100] In the support portion 540 of the end support piece 511, the wave rod located at the radial edge of the support portion 540 is designated as edge wave rod 5401, and the wave trough connected to the edge wave rod 5401 is designated as edge wave trough 5402. One end of the buffer rod 562 is connected to the buffer apex 561, and the other end is connected to the edge wave trough 5402 of the support portion 540. One end of the connecting rod 563 is connected to the buffer apex 561, and the other end overlaps with the edge wave rod 5401 of the support portion 540 to form an intersection point. The connecting rod 563 and the edge wave rod 5401 can slide relative to each other to a certain extent at this intersection point to prevent radial force from being directly transmitted to the support portion 540 and affecting the overall shape. In this embodiment, a constraint unit can be provided at the intersection of the connecting rod 563 and the edge wave rod 5401. For example, the constraint unit can be formed by stitching the intersection of the connecting rod 563 and the edge wave rod 5401 with the first covering film 51a to limit the degree of relative slippage between the connecting rod 563 and the edge wave rod 5401, and avoid excessive relative movement that would cause the radial support force of the buffer part 560 to be too low.

[0101] In this embodiment, each buffer section 560 contains one buffer rod 562. The buffer rod 562, the connecting rod 563, and the edge wave rod 5401 form a triangle or a triangular-like shape. In other embodiments, the number of buffer rods 562 can be multiple. The multiple buffer rods 562, the connecting rod 563, and the edge wave rod 5401 form a quadrilateral or other polygon.

[0102] In this embodiment, at least one end support piece 511 is movably connected to the axial end of the first bare bracket 512. Exemplarily, the end support piece 511 is hooked to the axial end of the first bare bracket 512. (Refer to...) Figure 8 The fourth bare bracket 511a and the third bare bracket 511b are respectively hooked to the axial end of the first bare bracket 512.

[0103] Reference Figure 11 In other embodiments, the end support piece 511 and the first bare bracket 512 are spaced apart in the axial direction, and there is a blank first covering film 51a between each end support piece 511 and the axial end of the first bare bracket 512. No support structure is provided on the blank first covering film 51a. The end support piece 511 and the axial end of the first bare bracket 512 are connected only through the blank first covering film 51a. Therefore, the end support piece 511 and the first bare bracket 512 can move relative to each other.

[0104] Reference Figure 12 In other embodiments, the fourth bare stent 511a is connected to the first bare stent 512 only through a blank first covering 51a, and the third bare stent 511b is hooked to the first bare stent 512. In other embodiments, the end support piece 511 and the first bare stent 512 can also be movably connected by an elastic element (such as a spring or elastic wire). By movably connecting the axial ends of the end support piece 511 and the first bare stent 512, when the covered stent 100 is implanted and bends towards the top surface, the end support piece 511 and the first bare stent 512 can move relative to each other, thereby allowing the top surface 51 to bend in segments. This reduces the risk of the embedded branch 510's internal space being squeezed or its branch opening being blocked due to bending following the main stent 10.

[0105] Please refer to Figure 8In this embodiment, the first bare support 512 includes a mesh structure 5120. Exemplarily, the mesh structure 5120 is integrally woven from support wires; in other embodiments, the mesh structure 5120 may be integrally cut. In this embodiment, the mesh structure 5120 includes multiple rows of interlaced units 5124 formed by multiple spaced-apart first-direction support wires 5121 and multiple spaced-apart second-direction support wires 5122, and deformable mesh openings 5123. The first-direction support wires 5121 extend generally along a first direction, and the second-direction support wires 5122 extend generally along a second direction. The first-direction support wires 5121 and the second-direction support wires 5122 overlap (or interweave) to form multiple rows of deformable mesh openings 5123 and multiple rows of interlaced units 5124. Each row of deformable mesh openings 5123 includes multiple deformable mesh openings 5123 arranged generally along the axial direction. Each row of interlaced units 5124 includes multiple interlaced units 5124 arranged generally along the axial direction. The deformable mesh 5123 is generally rhomboid in shape, but can also be square, rectangular, or other shapes. Four intersecting units 5124 are positioned at the four corners of the deformable mesh 5123. Each intersecting unit 5124 includes an intersection point formed by the overlapping of a first-direction support wire 5121 and a second-direction support wire 5122. At this intersection point, the first-direction support wire 5121 and the second-direction support wire 5122 can move relative to each other to a certain extent (or slide), and can also be fixed together by stitching or gluing. In some intersecting units 5124, the first-direction support wire 5121 is located on one side of the second-direction support wire 5122 (e.g., closer to the top opening 503), and in other intersecting units 5124, the first-direction support wire 5121 is located on the other side of the second-direction support wire 5122 (e.g., further away from the top opening 503). In other embodiments, the first directional support wires 5121 are all located on the side of the second directional support wires 5122 closer to the top opening 503, or the first directional support wires 5121 are all located on the side of the second directional support wires 5122 further away from the top opening 503. In this embodiment, the first bare support 512 is a mesh structure 5120. Compared with the spaced waveform units, the mesh structure 5120 can not only avoid shortening, but also bend as a whole when the covered support 100 bulges and bends in the direction of the top portion, so that the top portion 51 is appropriately raised, maintaining sufficient internal cavity space for the main support 10, and avoiding excessive bulging of the area of ​​the top portion 51 in the direction of the top opening 503, which would excessively occupy the internal space of the top portion 51. Therefore, it can reduce the risk that the top portion 51 will block the guide wire or bridging support from entering the embedded branch 510.

[0106] The axial end of the mesh structure 5120 also includes a plurality of connecting waves 5125, which are movably connected to the end support piece 511. Exemplarily, the mesh structure 5120 includes a plurality of proximal connecting waves 5125a and a plurality of distal connecting waves 5125b, wherein the proximal connecting waves 5125a are located at the proximal end of the mesh structure 5120 and are arranged radially spaced, and the distal connecting waves 5125b are located at the distal end of the mesh structure 5120 and are arranged radially spaced. Each proximal connecting wave 5125a bulges towards the fourth bare support 511a and is hooked to a corresponding trough in the fourth bare support 511a, such as... Figure 8 There are three proximal connecting waves 5125a, each of which is positioned opposite and hooked to the corresponding trough in the first waveform unit of the fourth bare stent 511a. Each distal connecting wave 5125b bulges towards the third bare stent 511b and is hooked to the corresponding trough in the third bare stent 511b, such as... Figure 8 There are three distal connecting waves 5125b, each of which is positioned opposite and hooked to the corresponding trough in the third waveform unit of the third bare support 511b. The mesh structure 5120 of this embodiment is hooked to the trough of the end support piece 511. Therefore, the end support piece 511 can bend relative to the mesh structure 5120 at the hook connection point, and the end support piece 511 and the mesh structure 5120 can achieve their respective bending deformations relatively independently. Furthermore, the mutual hooking method allows for a certain axial movement space between the end support piece 511 and the mesh structure 5120, enabling the mesh structure 5120, which is prone to axial elongation due to radial pressure, to have a certain axial extension space. This avoids excessive compression and interference between the end support piece 511 and the first bare support 512 when the top surface portion 51 deforms, thus preventing problems such as coating damage. In this embodiment, the connecting wave 5125 is evenly distributed radially on the top surface portion 51, so that the corresponding hook connection is also evenly distributed radially. This arrangement helps to better maintain the shape of the top surface portion 51 area between the end support piece 511 and the first bare bracket 512. When the coated bracket 100 bends toward the radial side, it can reduce the risk of bulging or irregular deformation of the top surface portion 51 area between the end support piece 511 and the first bare bracket 512.

[0107] It should be noted that the present invention does not limit the number of connecting waves 5125 on the mesh structure 5120. In other embodiments, the number of connecting waves 5125 can be adjusted according to actual needs. For example, there can be one or more connecting waves 5125.

[0108] Further, please refer to Figure 8 , Figure 9The width of the axial end of the mesh structure 5120 is less than the maximum width of the mesh structure 5120. For example, referring to... Figure 8 The mesh structure 5120 also includes a main body region located between the proximal connecting wave 5125a and the distal connecting wave 5125b, and has a width D1, which is the maximum width of the mesh structure 5120. Both axial ends of the mesh structure 5120 have a width D2, and the width D1 is greater than the width D2, so that the radial side of at least one axial end of the mesh structure 5120 has more blank film-coated area, so that there is a larger lateral bending space between the first bare support 512 and the end support piece 511, which is conducive to the top surface portion 51 better conforming to the lateral bending of the film-coated support 100.

[0109] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A covered stent, characterized in that, The covered stent includes a main stent and an auxiliary stent. Along the axial direction of the covered stent, the main stent includes a distal covered segment, a bare stent segment, and a proximal covered segment connected in sequence. The auxiliary stent is detachably disposed within the main stent and includes a connected auxiliary body and at least one embedded branch. The distal end of the auxiliary body is connected to the distal covered segment, and the distal end of the auxiliary body is closer to the proximal end of the covered stent than the distal end of the main stent. The proximal end of the auxiliary body is connected to the proximal covered segment. The distal covered segment, the auxiliary body, and the proximal covered segment together define a main channel. Along the radial direction of the covered stent, a space is defined between the outer peripheral surface of the auxiliary body and the inner wall surface of the bare stent segment. Each embedded branch connects the main channel and the space.

2. The covered stent according to claim 1, characterized in that, Along the axial direction of the covered stent, the auxiliary body includes a distal skirt, an auxiliary covered segment, and a proximal skirt connected in sequence. The distal skirt is embedded in the distal covered segment, and the proximal skirt is embedded in the proximal covered segment. Along the radial direction of the covered stent, the space is defined between the outer peripheral surface of the auxiliary covered segment and the inner wall surface of the bare stent. The auxiliary support includes multiple embedded branches, which are respectively connected to the distal skirt and / or the proximal skirt.

3. The covered stent according to claim 2, characterized in that, The auxiliary coating section includes a top surface portion and a bottom surface portion. The proximal end of the bottom surface portion is connected to the proximal skirt, and the distal end of the bottom surface portion is connected to the distal skirt. Along the circumference of the coating support, the top surface portion and the bottom surface portion are connected end to end and enclose to form a tubular structure. Along the radial direction of the covered support, the maximum spacing between the top portion and the bare support segment is greater than the maximum spacing between the bottom portion and the bare support segment.

4. The covered stent according to claim 3, characterized in that, The proximal end of the top surface portion and the inner wall of the proximal skirt define a first branch opening that communicates with the spacer space; the plurality of embedded branches include a first embedded branch, the first embedded branch including a first main body portion and a first transition portion, the first transition portion having a trumpet-shaped structure with a diameter gradually increasing from the proximal end to the distal end, the distal end of the first transition portion being connected to the proximal end of the top surface portion and the inner wall of the proximal skirt respectively, and communicating with the first branch opening, the proximal end of the first transition portion being connected to and communicating with the distal end of the first main body portion, and the proximal end of the first main body portion communicating with the main channel.

5. The covered stent according to claim 3, characterized in that, The distal end of the top surface portion and the inner wall of the distal skirt define a second branch opening that communicates with the spacer. The plurality of embedded branches include a second embedded branch, which includes a second main body portion and a second transition portion. The second transition portion has a trumpet-shaped structure with a diameter that gradually increases from the distal end to the proximal end. The proximal end of the second transition portion is connected to the distal end of the top surface portion and the inner wall of the distal skirt, and communicates with the second branch opening. The distal end of the second transition portion is connected to and communicates with the proximal end of the second main body portion. The distal end of the second main body portion communicates with the main channel.

6. The covered stent according to claim 2, characterized in that, At least one of the proximal skirt and the distal skirt includes a variable diameter section and a straight section whose diameter varies along the axial direction, the outer peripheral surface of the straight section being used to fit against the inner peripheral surface of the main support.

7. The covered stent according to claim 6, characterized in that, When the proximal skirt includes the variable diameter section; the covered support also includes a first inner skirt disposed within the proximal covered section, the first inner skirt being configured as a tapered structure with a gradually narrowing inner diameter from the distal end to the proximal end, the inner diameter of the proximal end of the first inner skirt being smaller than the outer diameter of the proximal end of the proximal skirt, and the proximal circumferential outer edge of the proximal skirt being able to abut against the inner wall surface of the first inner skirt; And / or, when the distal skirt includes the variable diameter section, the covering bracket further includes a second inner skirt disposed within the distal covering section. The second inner skirt is configured as a tapered structure with a gradually decreasing inner diameter from the proximal end to the distal end. The inner diameter of the distal end of the second inner skirt is smaller than the outer diameter of the distal end of the distal skirt. The distal circumferential outer edge of the distal skirt can abut against the inner wall surface of the second inner skirt.

8. The covered stent according to claim 6, characterized in that, The variable diameter section is provided with an inner wave ring, and the straight section is provided with an outer wave ring. The outer wave ring is used to radially abut against the inner wall of the main support. The diameter of the outer wave ring is larger than the diameter of the inner wave ring, and the radial support force of the inner wave ring is greater than the radial support force of the outer wave ring.

9. The covered stent according to any one of claims 2 to 8, characterized in that, The diameter of the bare stent segment is greater than the diameter of the distal covered segment and the proximal covered segment; and / or, the diameter of the auxiliary covered segment is smaller than the diameter of the distal skirt and the proximal skirt.

10. The covered stent according to any one of claims 3 to 8, characterized in that, The bare support segment is a developing element made of developable metal wire; And / or, at least one of the proximal skirt and the distal skirt is provided with a first developing element and a second developing element, the first developing element being located on the side of the top surface portion away from the central axis of the coating support along the radial direction of the coating support, and the second developing element being located on the side of the bottom surface portion away from the central axis of the coating support. And / or, the proximal skirt is provided with a first developing wire, the first developing wire extends circumferentially along the proximal skirt and is located at the distal end of the proximal skirt. Along the radial direction of the coating support, the first developing wire is located on the side of the top surface portion opposite to the central axis of the coating support. And / or, the proximal skirt is provided with a second developing filament, the second developing filament extending circumferentially along the distal skirt and located at the proximal end of the distal skirt. Along the radial direction of the coating support, the second developing filament is located on the side of the top surface portion opposite to the central axis of the coating support.

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