Covered stent, delivery device and covered stent delivery system

Abstract

The application provides a covered stent, a delivery device and a covered stent delivery system, and relates to the field of medical devices. The covered stent comprises a stent body and a linear bending component. The linear bending component is connected to the proximal small bending side of the stent body and extends along the covering film of the stent body from the proximal end of the stent body to the distal end of the stent body. The linear bending component is configured to provide constraint to the covering film and / or the stent unit on the small bending side of the stent body along the extension direction of the linear bending component, so that at least one group of stent rings of the stent unit one and the stent unit two are close to each other on the small bending side of the stent body, thereby causing the covering film between the corresponding stent unit one and the stent unit two to be wrinkled. The delivery device is used for delivering the covered stent. The covered stent delivery system comprises the covered stent and the delivery device. The application solves the problem of the bird beak sign on the proximal small bending side of the covered stent after the covered stent is implanted and the problem of type Ia endoleak.

Description

Technical Field

[0001] This invention relates to the technical field of medical devices, and in particular to a covered stent, a delivery device, and a covered stent delivery system. Background Technology

[0002] Aortic diseases such as aortic dissection, true aortic aneurysm, pseudoaneurysm, and penetrating aortic ulcer pose a serious threat to human health, with rapid onset, rapid progression, and extremely high mortality.

[0003] Thoracic endovascular aortic repair (TEVAR) is an effective treatment for aortic disease, offering significant advantages over open-chest surgery, including less trauma and fewer complications. Through an incision in the distal aorta, such as the femoral artery, a delivery system loaded with a covered stent is advanced to the lesion site. The stent is then released and fixed to the vessel wall, isolating the diseased artery and reconstructing the blood supply, thus achieving the therapeutic goal.

[0004] Because the aortic arch is naturally curved, while aortic endovascular stent grafts are cylindrical, they often fail to adhere perfectly to the vessel wall after implantation. This is especially true in patients with steep aortic arches and sharp curves, where the stent graft struggles to conform to the vessel's natural shape, creating a wedge-shaped or acute-angled gap between the proximal stent and the aortic wall. This gap, resembling a bird's beak, is often referred to as the "bird's beak sign." Studies have shown that the presence of this sign significantly increases the risk of type Ia endoleaks. Blood can continuously enter the aneurysm lumen or dissection false lumen through this gap, preventing effective isolation of the lesion area and potentially leading to aneurysm rupture and dissection progression (the tear in the dissection continues to expand). Furthermore, the prolonged impact of blood flow on the poorly adhered proximal stent can cause stent displacement and deformation, further exacerbating the poor apposition. Studies show that when the angle of the bird's beak sign is <30° and the length is >10mm, the incidence of endoleak increases significantly (up to 30%-50%), requiring active intervention (such as balloon dilation, patch repair, or re-implantation of a stent).

[0005] Currently, some existing technologies use the mechanical structure of the delivery device to temporarily pull or press on the lesser curvature side of the intravascular stent during release, causing the lesser curvature side of the stent to adhere to the vessel wall and thus improving the "bird's beak sign." The delivery device is then withdrawn from the body. However, due to the stent's recoil force, the "bird's beak sign" can reappear after the lesser curvature side adheres to the vessel wall due to vascular pulsation and blood flow impact, potentially leading to endoleak. Simultaneously, the stent's recoil force can repeatedly irritate the vessel wall at the proximal and distal greater curvature sides of the stent, causing new ruptures, often referred to as stent-induced ruptures (SINE). Summary of the Invention

[0006] The purpose of this invention is to provide a covered stent, a conveyor, and a covered stent delivery system to alleviate the aforementioned technical problems existing in the prior art.

[0007] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0008] In a first aspect, embodiments of the present invention provide a covered stent, comprising a stent body, the stent body including a skeleton and a covering film connected to the surface of the skeleton, the skeleton including multiple stent rings spaced apart along the axial direction of the stent body; each stent ring having multiple V-shaped or arc-shaped stent units connected end to end along the circumference of the stent body; the radially opposite sides of the stent body are respectively the large bend side and the small bend side of the stent body in a bent state; each pair of adjacent stent rings along the axial direction of the stent body forms a group, and in each group of stent rings, at least one stent unit of the stent ring located on the proximal side is stent unit one, and at least one stent unit of the stent ring located on the distal side is stent unit two;

[0009] The film-coated support also includes a linear bending adjustment component;

[0010] The linear bending member is connected to the proximal small bend side of the stent body and extends along the film of the stent body from the proximal end to the distal end of the stent body. The linear bending member is configured to provide constraint on the film and / or stent unit on the small bend side of the stent body along its extension direction, so that stent unit one and stent unit two of at least one set of stent rings move closer to each other on the small bend side of the stent body, thereby creating wrinkles in the film between the corresponding stent unit one and stent unit two.

[0011] In an optional embodiment, the side of the covering film facing the interior of the support body is defined as the inner side of the covering film, and the side of the covering film facing the exterior of the support body is defined as the outer side of the covering film.

[0012] The linear bending component is a bending line. One end of the bending line facing the proximal end of the support body is fixedly connected to the support body, and the other end of the bending line facing the distal end of the support body is a free end for pulling. The bending line passes through the film and is in frictional engagement with the perforations on the film through which the bending line passes.

[0013] Alternatively, the linear bending component is a spring, with both ends of the spring fixedly connected to the support body. The spring is inserted inside and outside the membrane and is configured to release elastic potential energy in a free state, so as to pull the support unit one and support unit two, which are at least one set of support rings between the two ends of the spring, closer to each other.

[0014] In an optional embodiment, the linear bending component is a spring, which is located inside the support body, wherein:

[0015] Both ends of the spring are fixedly connected to the bracket body, and the portion of the spring located between the two ends is suspended from the bracket body;

[0016] Alternatively, the spring comprises multiple segments, with each segment having its two ends fixedly connected to the proximal end of the distal end of support unit one in a set of support rings and the distal end of the distal end of support unit one after support unit one and support unit two approach each other.

[0017] In an optional embodiment, along the axial direction of the covered support:

[0018] The points where the linear bending component is fixed or passes through the film are located on the proximal side of the distal end of the corresponding support unit, or are flush with the distal end of the corresponding support unit.

[0019] In an optional embodiment, the linear bending component passes through the membrane from the outside of the membrane to the inside of the membrane at the proximal end of the distal end of the support unit 1.

[0020] The linear bending component passes through the membrane from the inside to the outside of the membrane at the proximal end of the distal end of the second support unit.

[0021] In an optional embodiment, along the axial direction of the covered support: the axial distance between the support unit one and the support unit two is h1, and the axial distance between the point where the linear bending component passes through the covered film on the proximal side of the distal end of the support unit two and the proximal end of the support unit two is h2, satisfying: h2≥h1.

[0022] In an optional embodiment, along the axial direction of the covered stent, one end of the linear bending member facing the proximal side of the covered stent is fixed between the proximal end of the covered stent and the distal end of the corresponding stent unit of the nearest stent ring.

[0023] In a second aspect, embodiments of the present invention provide a conveyor for conveying a film-coated stent provided in any of the optional embodiments of the first aspect; the conveyor includes an outer sheath, a central tube, a guide head, and a rear release device;

[0024] The guide head is fixed to the distal end of the central tube, and the outer sheath is fitted onto the outside of the central tube;

[0025] The rear release device includes a push tube and a rear release claw;

[0026] The push tube passes through the outer sheath and is fitted onto the outside of the central tube;

[0027] The rear release claw includes a connecting part and a fork; the connecting part is fixedly connected to the distal end of the push tube and has a through hole extending through the axial direction of the push tube inside; the fork includes at least one long rod, the proximal end of the long rod is fixedly or integrally connected to the connecting part, and the distal end of the long rod extends to the distal end side of the connecting part; and the long rod is arranged radially along the push tube on one side of the connecting part.

[0028] In a further optional embodiment, the fork also includes at least two short bars;

[0029] The proximal ends of all the forks are fixedly connected to the connecting part at uniform intervals along the circumference of the push tube, and the distal ends of all the forks extend to the distal end side of the connecting part. The long rod and the short rod are respectively arranged on opposite sides of the connecting part along the radial direction of the push tube, and the distal end of the long rod is located on the distal end side of the distal end of the short rod.

[0030] in:

[0031] The distal surfaces of all the forks are on the same inclined plane that is inclined relative to the radial cross-section of the push tube; or, the distal surfaces of each fork are parallel to the radial cross-section of the push tube, the distal surfaces of all the long rods are on the same surface, and the distal surfaces of all the short rods are on the same surface.

[0032] And / or, the guide head has multiple axial limiting grooves on its circumferential surface that correspond one-to-one with the multiple forks, and the axial limiting grooves pass through the proximal end face of the guide head.

[0033] In an optional embodiment, the linear bending component is a bending wire, one end of which is fixedly connected to the support body near the proximal end, and the other end of which is a free end for pulling. The bending wire passes through the film and frictionally engages with perforations in the film through which it passes.

[0034] The free end of the bending line is integrally or fixedly connected with a pull ring;

[0035] The conveyor also includes a bending tube and a bending cable; the bending tube passes through the outer sheath tube, and in the conveying state, the bending cable passes through the pull ring and confines the pull ring inside the bending tube. By retracting the bending cable, the pull ring can be released from the bending cable.

[0036] Thirdly, embodiments of the present invention provide a covered stent delivery system, including a covered stent provided by any optional embodiment of the first aspect and a delivery device provided by any optional embodiment of the second aspect.

[0037] In particular, in the embodiments of the present invention, "and / or" means that the first feature before "and / or" and the second feature after "and / or" include the following specific settings: (1) only the first feature is set, and the second feature is not set; (2) only the second feature is set, and the first feature is not set; (3) the first feature and the second feature are set at the same time.

[0038] The embodiments of the present invention can achieve at least the following beneficial effects:

[0039] For the covered stent provided in the embodiments of the present invention, after it is implanted into a patient's tortuous blood vessel (including but not limited to the aortic arch blood vessel) by a delivery device, at least one set of stent rings of stent unit one and stent unit two are close to each other on the small bend side of the stent body at the proximal end and near the proximal region of the covered stent, thereby creating wrinkles in the covering between the corresponding stent unit one and stent unit two, ensuring that the covering on the small bend side of the proximal end of the covered stent adheres to the inner wall of the blood vessel, eliminating the "bird's beak sign" that exists on the small bend side of the covered stent after implantation in the prior art, and preventing type Ia endoleak (for other effects, please refer to the specific implementation section of the specification).

[0040] For the delivery device provided in the embodiments of the present invention, by setting a post-release device, when the proximal end of the covered stent is released into the blood vessel, the stent unit with the stent ring at the nearest end of the covered stent in the small bend is released first to adjust the wall apposition state of the covered stent on the small bend side, and then the stent unit with the stent ring at the nearest end of the covered stent in the large bend side is released. When adjusting the wall apposition state of the covered stent on the small bend side, the long rod radially constrains the stent unit on the large bend side of the proximal end of the covered stent and provides these stent units with support and positioning capability toward the proximal end of the covered stent. This provides flexibility for the adjustment of the small bend side of the covered stent while preventing the covered stent from shifting under the action of blood flow (for other effects, please refer to the detailed implementation section of the specification).

[0041] The functional effects that the covered stent delivery system provided in the embodiments of the present invention can achieve are the same as those described above for the covered stent and the delivery device. Attached Figure Description

[0042] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 A schematic diagram illustrating the "bird's beak sign" that appears proximally when a covered stent is implanted into a curved vessel (such as the aortic arch) in the prior art;

[0044] Figure 2 This is a schematic diagram illustrating the elimination of the "bird's beak sign" caused by the proximal stacking of the covered stent after implantation into a tortuous blood vessel, as provided in an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the shape of the covered stent before stacking in an optional embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the stacked shape of an optional embodiment of the covered stent provided in this invention.

[0047] Figure 5 This is a schematic diagram of the shape of the covered stent in optional embodiment two before stacking, as provided in this invention.

[0048] Figure 6 This is a schematic diagram of the stacked shape of the film-coated stent in an optional embodiment two of the present invention.

[0049] Figure 7 This is a schematic diagram of the shape of the covered stent in optional embodiment three before stacking, as provided in the present invention.

[0050] Figure 8 This is a schematic diagram of the stacked shape of the film-coated stent in an optional embodiment three of the present invention.

[0051] Figure 9 This is a schematic diagram of the shape of the covered stent in optional embodiment four before stacking, provided by the present invention.

[0052] Figure 10 This is a schematic diagram of the stacked shape of the film-coated stent in an optional embodiment four of the present invention.

[0053] Figure 11 This is a schematic diagram of the shape of the film-coated stent in optional embodiment five before stacking, as provided in the embodiments of the present invention;

[0054] Figure 12 This is a schematic diagram of the stacked shape of the film-coated stent in optional embodiment five of the present invention;

[0055] Figure 13 This is a schematic diagram of the structure of the distal side of an optional embodiment of the conveyor provided in this invention.

[0056] Figure 14 for Figure 13A schematic diagram of the overall structure of the rear release claw of the rear release device in the provided conveyor;

[0057] Figure 15 This is a schematic diagram of the structure of the distal side of an optional embodiment two of the conveyor provided in this invention.

[0058] Figure 16 for Figure 15 A schematic diagram of the overall structure of the rear release claw of the rear release device in the provided conveyor;

[0059] Figure 17 A schematic diagram illustrating the implantation method of a covered stent with the bending wire as a linear bending component when the delivery device provided in the embodiments of the present invention further includes a bending tube and a bending cable;

[0060] Figure 18 for Figure 17 In the implanted state, a schematic diagram of the assembly relationship between the bending tube, the bending cable, and the bending line of the covered stent is shown.

[0061] Figure 19 for Figure 17 In the implanted state, a schematic diagram of another assembly relationship between the bending tube, the bending cable, and the bending line of the covered stent;

[0062] Figure 20 For Figure 17 The diagram shows the state of the covered stent within the blood vessel after the implantation of the covered stent and the removal of the delivery device.

[0063] Icons: 100-Laminated support; 1-Support unit one; 2-Support unit two; 3-Linear bending component; 301-Proximal fixing point; 31-Pull ring;

[0064] 200-Conveyor; 4-Outer sheath; 5-Center tube; 6-Guide head; 61-Axial limiting groove; 7-Rear release device; 71-Push tube; 72-Rear release claw; 721-Connecting part; 722-Fork; 7221-Long rod; 7222-Short rod; 8-Adjusting tube; 9-Adjusting cable. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0066] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0067] It should be noted that similar labels and letters in the accompanying drawings indicate similar items. Therefore, once an item is defined in one accompanying drawing, it does not need to be further defined and explained in subsequent accompanying drawings.

[0068] In the description of this invention, it should be noted that:

[0069] Unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0070] The terms “proximal end,” “distal end,” “front end,” “rear end,” “axial,” “radial,” “circumferential,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0071] Specifically, in this application:

[0072] (1) For covered stents, when blood flows through the covered stent after it is implanted into the patient’s body, the inflow end of the blood flow is the proximal end of the covered stent, and the outflow end of the blood flow is the distal end of the covered stent.

[0073] (2) For the delivery device, its front end (i.e. the end closer to the patient) is its distal end, and its rear end (the end closer to the operator) is its proximal end.

[0074] In addition, in this application, the terms "first," "second," etc., are used only for distinguishing descriptions and do not indicate totality or relative position in time and / or space, and should not be construed as indicating or implying relative importance.

[0075] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings.

[0076] First aspect

[0077] Reference Figure 1 In existing technologies, when a covered stent is implanted into a patient's curved blood vessel (such as a vessel in the aortic arch), it is difficult to conform to the natural shape of the blood vessel. A "wedge-shaped" or "acute-angled" gap is formed between the proximal small curve of the covered stent and the inner wall of the blood vessel. Because it resembles a bird's beak, it is called the "bird's beak sign".

[0078] In this embodiment, a covered stent 100 is provided, referring to... Figures 1 to 12 Its basic structure includes a support body, which includes a skeleton and a membrane connected to the surface of the skeleton. The skeleton includes multiple support rings spaced apart along the axial direction of the support body. Each support ring has multiple V-shaped or arc-shaped support units connected end to end along the circumference of the support body. The radially opposite sides of the support body are the large bending side and the small bending side of the support body in a bent state. Each pair of adjacent support rings along the axial direction of the support body is a group. In each group of support rings, at least one support unit of the support ring located on the proximal side is support unit 1, and at least one support unit of the support ring located on the distal side is support unit 2.

[0079] Specifically, the covered stent 100 also includes a linear bending member 3; the linear bending member 3 is connected to the proximal small bend side of the stent body and extends along the covering from the proximal end of the stent body to the distal end of the stent body; the linear bending member 3 is configured to provide constraint on the covering and / or stent unit on the small bend side of the stent body along its extension direction, so that stent unit 1 and stent unit 2 of at least one set of stent rings move closer to each other on the small bend side of the stent body, thereby creating wrinkles in the covering between the corresponding stent unit 1 and stent unit 2.

[0080] In use, the covered stent 100 is implanted into the patient's tortuous blood vessels (including but not limited to the aortic arch vessels) using a delivery device. After implantation, refer to... Figure 2 At the proximal end and near the proximal region of the covered stent 100, at least one set of stent rings, stent unit 1 and stent unit 2, are close to each other on the small bend side of the stent body, thereby creating folds in the covering between the corresponding stent unit 1 and stent unit 2. This ensures that the covering on the proximal small bend side of the covered stent 100 adheres to the inner wall of the blood vessel, eliminating the "bird's beak sign" that exists on the proximal small bend side of the covered stent after implantation in the prior art, and preventing type Ia endoleak.

[0081] It should be noted that in this embodiment, when support unit 1 and support unit 2 are close to each other, the two support units may stack or simply be close without stacking.

[0082] The number, wave height, and wave width of the support units in each pair of adjacent support rings can be the same or different. Taking the proximal end of the support ring as the upper end and the distal end as the lower end, on the small bend side of the support ring, the axial arrangement of support unit 1 and support unit 2 in each group of support rings can be such that the peak of support unit 1 is directly opposite the peak of support unit 2, or the peak of support unit 1 is directly opposite the trough of support unit 2, or the peaks and troughs of the two are interleaved. In order to better achieve the function and avoid the excessive axial spacing between support unit 1 and support unit 2 to reduce the radial support force of the support body, preferably, each group of support rings is arranged so that the peak of support unit 1 is directly opposite the peak of support unit 2 in the axial direction, or, on the nearest end side, the peak of support unit 1 is directly opposite the trough of support unit 2, and the other groups of support rings are arranged so that the peak of support unit 1 is directly opposite the peak of support unit 2 in the axial direction.

[0083] Additionally, it should be noted that in this embodiment, "each set of support rings" refers to every two adjacent support rings along the axial direction of the support body. Along the axial direction of the support body, one support ring on the distal side of one set of support rings can serve as one support ring on the proximal side of another set of support rings; that is, two adjacent sets of support rings can share one support ring. In this embodiment, the linear bending component 3 is connected to the support body and includes a skeleton connected to the support body, a covering film connected to the support body, or both a skeleton and a covering film connected to the support body simultaneously.

[0084] More specifically, the covered stent 100 provided in this embodiment has at least the following specific optional implementation methods:

[0085] Optional Implementation Method 1:

[0086] Reference Figure 3 and Figure 4 The nearest set of support rings is arranged such that the crest of support unit 1 is directly opposite the trough of support unit 2, and the other sets of support rings are arranged such that the crest of support unit 1 is directly opposite the crest of support unit 2 in the axial direction; the linear bending component 3 is a bending line, with one end of the bending line facing the near end of the support body fixedly connected to the support body, and the other end of the bending line facing the far end of the support body being the free end for pulling; the side of the film facing the inside of the support body is the inner side of the film, and the side of the film facing the outside of the support body is the outer side of the film: the bending line passes through the film inward and outward and is in frictional engagement with the perforations on the film through which the bending line passes.

[0087] In this optional embodiment, the bending adjustment line can be a suture or a metal wire. After the covered stent 100 is implanted into the target blood vessel, the bending adjustment line is located on the minor bend side of the stent body. Pulling the bending adjustment line distally can bend the covered stent 100, achieving stacking between stent unit 1 and stent unit 2, and ensuring the minor bend side adheres to the vessel wall, thus avoiding endoleak and the "bird's beak sign". Because the bending adjustment line has friction with the covered stent at the repeated insertion and exit points, it can effectively overcome the straightening force of the stent body itself, allowing the covered stent 100 to stably maintain a curved structure equivalent to the curved blood vessel. This ensures the long-term stability of the minor bend side of the covered stent 100 adhering to the vessel wall, preventing the covered stent 100 from tending to straighten back under factors such as blood flow impact and cardiac pulsation, and avoiding the re-formation of the "bird's beak" or SINE in the long term.

[0088] It should be noted that the extension trajectory of the adjustment line along the covered surface is not necessarily a straight line extending along the generatrix of the stent body; it can also be an oblique line or a curve to allow the slightly curved side of the covered stent 100 to adapt to the tortuous structure of the blood vessel after implantation. Specifically, the adjustment line can be arranged in at least the following ways on the covered surface:

[0089] In the first optional arrangement, there is one bending line, which is as follows: Figures 3 to 6 As shown, it is located on the small bend side of the support body and extends along the generatrix direction of the support body on the film;

[0090] In the second optional arrangement, there is a bending line, and the extension trajectory of the bending line on the unfolded surface of the film is an oblique line inclined to the main body of the support.

[0091] In the third optional arrangement, there are at least two bending lines. These bending lines are located on the small bend side of the support body and on different sides of the circumference of the support body. The near ends of each pair of adjacent bending lines can be fixedly connected at the same or different axial distances as the near ends of the support body. Each bending line extends along the generatrix of the support body, or the extension trajectory on the unfolded surface of the film is an oblique line inclined to the generatrix of the support body.

[0092] Taking the aorta as the target vessel, when the aorta is tortuous, there may be other curvatures besides the arch. By arranging the bending line according to the second and third optional arrangement methods mentioned above, the bending of the small curvature side of the covered stent 100 is more flexible, and the small curvature side of the covered stent 100 can better adapt to the curvature of the tortuous vessel.

[0093] In an optional embodiment, the linear bending component 3 is fixed or passes through the film at various points located on the proximal side of the distal end of the corresponding support unit, or is flush with the distal end of the corresponding support unit, thereby ensuring that support unit 1 and support unit 2 can be stacked regularly and to a large extent when they are close to each other, ensuring maximum bending and thus ensuring the effect of preventing internal leakage.

[0094] In an optional embodiment, the bending line passes through the covering from the outer side to the inner side of the covering at the proximal side of the distal end of stent unit 1; the bending line passes through the covering from the inner side to the outer side of the covering at the proximal side of the distal end of stent unit 2. In this optional embodiment, this design allows the stacked stent units to be orderly stacked when they are close to each other after bending, so that the distal end of stent unit 1 is located inside the proximal end of stent unit 2. This not only has the shortest bending path, but also allows the covered stent 100 after bending to conform to the blood flow, without forming a "sail effect", avoiding obstruction of blood flow at the stacking point and the formation of thrombi.

[0095] In alternative implementations, such as Figure 3 As shown, along the axial direction of the film-coated support 100: the axial distance between support unit 1 and support unit 2 is h1, and the axial distance between the point where the bending line passes through the film on the proximal side of the distal end of support unit 2 and the proximal end of support unit 2 is h2, satisfying: h2≥h1. In this optional embodiment, due to the presence of the support ring, the bending line will not cause the film to shorten and wrinkle (solid line part) in the area outside the support body where the bending line is located, but will only cause the film wrinkles in the area inside the support body where the bending line is located to stack regularly. Therefore, the bending can be further ensured to the maximum extent.

[0096] Optional Implementation Method Two:

[0097] Reference Figure 5 and Figure 6 The linear bending component 3 is a bending line. Unlike the optional embodiment one, in this optional embodiment, each group of support rings is arranged so that the peak of the support unit 1 is directly opposite the peak of the support unit 2 in the axial direction. The other features are the same as those in optional embodiment one.

[0098] Optional Implementation Method 3:

[0099] Reference Figure 7 and Figure 8The linear bending component 3 is a spring (preferably a micro spring). Both ends of the spring are fixedly connected to the support body. The side of the film facing the inside of the support body is the inner side of the film, and the side of the film facing the outside of the support body is the outer side of the film. The spring is inserted into the film and is configured to release elastic potential energy in a free state to pull the support unit 1 and support unit 2 of at least one set of support rings between the two ends of the spring closer to each other.

[0100] In this embodiment, there may be friction between the spring and the perforation on the cover through which the spring passes, or there may be a movable gap. When there is a movable gap, the covered stent 100 bends better adapts to the curvature of the blood vessel, and the cover can fit more closely to the inner wall of the blood vessel.

[0101] In an optional implementation, the points where the spring is fixed or passes through the membrane are located on the proximal side of the distal end of the corresponding support unit, or are flush with the distal end of the corresponding support unit, so as to ensure that support unit 1 and support unit 2 can be stacked regularly and to a large extent when they are close to each other, so as to ensure that they can be bent to the maximum extent and thus ensure the effect of preventing internal leakage.

[0102] In an optional embodiment, the spring passes through the membrane from the outside to the inside of the membrane at the proximal end of the distal end of stent unit 1; the spring passes through the membrane from the inside to the outside of the membrane at the proximal end of the distal end of stent unit 2. In this optional embodiment, this design allows the stacked stent units after bending to be stacked in an orderly manner when they are close to each other, so that the distal end of stent unit 1 is located inside the proximal end of stent unit 2. This not only has the shortest bending path, but also allows the bent covered stent 100 to conform to blood flow, without forming a "sail effect", avoiding obstruction of blood flow at the stacking point and the formation of thrombi.

[0103] In an optional embodiment, along the axial direction of the film-coated support 100: (Refer to...) Figure 3 The axial distance between support unit 1 and support unit 2 is h1, and the axial distance between the point where the spring passes through the film on the proximal side of the distal end of support unit 2 and the proximal end of support unit 2 is h2, satisfying: h2≥h1. In this optional embodiment, due to the presence of the support ring, the spring will not cause the film on the outer side of the support body to shorten and wrinkle (solid line portion), but will only cause the film on the inner side of the support body to stack in a regular manner, thus further ensuring maximum bending adjustment.

[0104] In this optional embodiment, the spring is located on the small curved side of the support body and extends along the generatrix of the support body on the film; or, the extension trajectory of the spring on the unfolded surface of the film is an oblique line inclined to the generatrix of the support body.

[0105] Taking the aorta as the target vessel, when the aorta is tortuous, there may be other curvatures besides the arch. When the extension trajectory of the spring on the unfolded surface of the endovascular stent is an oblique line inclined to the generatrix of the stent body, the spring can bend the small curved side of the endovascular stent 100 more flexibly, which can make the small curved side of the endovascular stent 100 better adapt to the curvature of the tortuous vessel.

[0106] Optional Implementation Method Four:

[0107] The linear bending component 3 is a spring (preferably a micro-spring), located inside the support body. Both ends of the spring are fixedly connected to the support body, while the portion of the spring between the two ends is suspended above the support body. In this optional embodiment, compared to optional embodiment three, the spring does not penetrate the film, eliminating friction between it and the film perforations; friction only exists between it and the stacked films. This lower friction allows for a more uniform bending force on the bending section of the film-coated support 100.

[0108] Similarly, in this optional embodiment, the spring is located on the small curved side of the support body and extends along the generatrix of the support body on the film; or, the extension trajectory of the spring on the unfolded surface of the film is an oblique line inclined to the generatrix of the support body.

[0109] Taking the aorta as the target vessel, when the aorta is tortuous, there may be other curvatures besides the arch. When the extension trajectory of the spring on the unfolded surface of the endovascular stent is an oblique line inclined to the generatrix of the stent body, the spring can bend the small curved side of the endovascular stent 100 more flexibly, which can make the small curved side of the endovascular stent 100 better adapt to the curvature of the tortuous vessel.

[0110] Optional Implementation Method Five:

[0111] The linear bending component 3 is a spring (preferably a micro-spring) located inside the support body. The spring comprises multiple segments, each segment having its ends fixedly connected to the proximal end of the distal end of support unit 1 in a set of support rings and the distal end of the distal end of support unit 1 after it is stacked with support unit 2. This configuration allows support unit 1 to automatically stack onto support unit 2 after the spring contracts. Furthermore, each spring segment can be used to bend support unit 1 and support unit 2 in adjacent support rings, with the bending degree and force adjustable. This makes the bending force on the bent section of the covered support 100 more controllable and improves wall adhesion.

[0112] In this optional embodiment, the spring comprises at least two segments, and the specific arrangement of these segmented springs on the film includes at least the following:

[0113] In some arrangements, these segmented springs are arranged on the same side of the circumference of the support body along the generatrix direction of the support body.

[0114] In other arrangements, these segmented springs are located on the small bend side of the support body and on different sides of the circumference of the support body. Furthermore, the near ends of each pair of adjacent bending lines can be fixedly connected at the same or different axial distances as the near ends of the support body. Each spring extends along the generatrix of the support body, or its extension trajectory on the unfolded surface of the film is an oblique line inclined to the generatrix of the support body.

[0115] Taking the aorta as the target vessel, when the aorta is tortuous, there may be other curvatures besides the arch. When these segmented springs are placed on the small bend side of the stent body and located on different sides of the circumference of the stent body, the springs can bend the small bend side of the covered stent 100 more flexibly, so that the small bend side of the covered stent 100 can better adapt to the curvature of the tortuous vessel and improve the anti-leakage effect of the small bend side of the covered stent 100. In any of the above optional embodiments three to five, the spring is preferably made of superelastic nickel-titanium alloy wire, which is a tension spring with a tendency to shorten. The shortening tension is greater than the straightening force of the stent body. When the covered stent 100 is loaded into the delivery device 200, the spring is stretched, causing the covered stent 100 to elongate axially. There are no wrinkles on its small curved side. After the covered stent 100 is released from the delivery device 200 into the blood vessel lumen, it can automatically adjust its bend under the tension force of the spring. The elastic potential energy of the spring ensures the long-term effect and avoids the covered stent 100 straightening back and causing stent-induced rupture.

[0116] In addition, in any of the above optional embodiments of this example, it is further optional that, along the axial direction of the covered support 100, one end of the linear bending member 3 facing the proximal side of the covered support 100 is fixed between the proximal end of the covered support and the distal end of the corresponding support unit of the nearest support ring as the proximal fixing point 301 of the linear bending member 3. It should be noted that when the linear bending member 3 is a segmented structure, the end of the linear bending member 3 facing the proximal side of the covered support 100 refers to the end of the most recent segment of the linear bending member 3 facing the proximal side of the covered support 100.

[0117] Second aspect

[0118] This embodiment provides a conveyor 200 for conveying the film-coated support 100 provided in any optional embodiment of the first aspect described above; see reference Figures 13 to 16 The conveyor 200 includes an outer sheath 4, a central tube 5, a guide head 6, and a rear release device 7.

[0119] Specifically, the guide head 6 is fixed to the distal end of the central tube 5. The outer sheath 4 is fitted onto the outside of the central tube 5. The rear release device 7 includes a push tube 71 and a rear release claw 72; the push tube 71 passes through the outer sheath 4 and is fitted onto the outside of the central tube 5; the rear release claw 72 includes a connecting part 721 and a fork 722; the connecting part 721 is fixedly connected to the distal end of the push tube 71 and has a through hole extending axially along the push tube 71 inside; the fork 722 includes at least one long rod 7221, the proximal end of the long rod 7221 is fixed or integrally connected to the connecting part 721, and the distal end of the long rod 7221 extends to the distal end side of the connecting part 721; and the long rod 7221 is arranged radially along the push tube 71 on one side of the connecting part 721.

[0120] To avoid confusion between proximal and distal ends, the proximal end of the delivery device 200 is considered its front end, and the distal end of the delivery device 200 is considered its rear end. After implantation of the covered stent 100, the blood inflow end is considered its proximal end, and the blood outflow end is considered its distal end. The implantation method of the covered stent 100 using this delivery device 200 is described below:

[0121] When in use, the film-coated bracket 100 is fitted outside the central tube 5, and the far end of the film-coated bracket 100 is inserted into the front end of the push tube 71, so that the long rod 7221 of the fork 722 of the rear release claw 72 passes through the bracket unit with the nearest bracket ring on the large bend side of the film-coated bracket 100.

[0122] Then, the outer sheath tube 4 is pushed forward relative to the central tube 5 and the push tube 71 so that the entire covered stent 100 enters the front end of the outer sheath tube 4;

[0123] Insert a guidewire into the target blood vessel, and place the guide head 6 and central tube 5 over the outside of the guidewire. Under the guidance of the guidewire, insert the delivery device 200 into the blood vessel. After it is pushed into place, retract the outer sheath 4 relative to the delivery tube 71 and central tube 5 or push the delivery tube 71 and central tube 5 forward relative to the outer sheath 4 so that the proximal end of the covered stent 100 is released into the target blood vessel.

[0124] The stent unit with the most proximal segment of the covered stent 100 on the minor bend side adheres to the vessel wall. The wall-adhering state of the covered stent 100 on the minor bend side is adjusted to ensure that the stacking of the covered stent 100 on the proximal minor bend side avoids the "bird beak sign".

[0125] After the apposition of the covered stent 100 on the small bend side is adjusted, the push tube 71 is withdrawn so that the stent unit with the most proximal stent ring on the large bend side is released by the long rod 7221 and abuts against the blood vessel wall.

[0126] The implantation process is then completed by removing the delivery unit 200.

[0127] The delivery device 200 provided in this embodiment, by setting a post-release device 7, releases the stent unit with the stent ring at the proximal end of the covered stent 100 into the blood vessel first, and then releases the stent unit with the stent ring at the proximal end of the covered stent 100 on the small bend side to adjust the wall apposition state of the covered stent 100 on the small bend side. Then, it releases the stent unit with the stent ring at the proximal end of the covered stent 100 on the large bend side. When adjusting the wall apposition state of the covered stent 100 on the small bend side, the long rod 7221 radially constrains the stent unit on the large bend side of the proximal end of the covered stent 100 and provides these stent units with support and positioning capability toward the proximal end of the covered stent 100. This provides flexibility for the adjustment of the small bend side of the covered stent 100 while preventing the covered stent 100 from shifting under the action of blood flow.

[0128] Furthermore, in some optional embodiments, the fork 722 further includes at least two short rods 7222; the proximal ends of all fork rods 722 are uniformly spaced and fixedly connected to the connecting portion 721 along the circumference of the push tube 71, and the distal ends of all fork rods 722 extend to the distal end side of the connecting portion 721, with the long rod 7221 and the short rods 7222 respectively arranged on opposite sides of the connecting portion 721 along the radial direction of the push tube 71, and the distal end of the long rod 7221 located on the distal end side of the distal end of the short rod 7222. Wherein: Refer to Figure 13 and Figure 14 As an optional embodiment of the conveyor 200, in the rear release claw 72 of the rear release device 7, the distal (front) surfaces of each fork 722 are parallel to the radial cross-section of the push tube 71. The distal (front) surfaces of all long rods 7221 are on the same surface, and the distal (front) surfaces of all short rods 7222 are on the same surface; that is, the distal (front) surfaces of all long rods 7221 and the distal (front) surfaces of all short rods 7222 form a stepped surface. (Refer to...) Figure 15 and Figure 16 As an alternative embodiment of the conveyor 200, in the rear release claw 72 of the rear release device 7, the distal (front) surfaces of all the forks 722 are on the same inclined plane that is inclined relative to the radial cross-section of the push tube 71.

[0129] In this optional embodiment, during use, among the forks 722 of the rear release claw 72, the long rods 7221 pass through the support unit of the nearest support ring of the covered support 100 on the large bend side, and the short rods 7222 pass through the support unit of the nearest support ring of the covered support 100 on the small bend side, so as to radially constrain the nearest support ring of the covered support 100.

[0130] The post-release device 7 includes two post-releases. Before the post-release, after the covered stent 100 is released from the outer sheath 4, the stent ring at the nearest end of the covered stent 100 is still in a radially constrained state, which can be used to adjust the position of the covered stent 100 to make the alignment of the covered stent 100 more accurate. During the first release, the stent unit with the stent ring at the nearest end of the covered stent 100 on the small bend side is released and attached to the vessel wall by the short rod 7222, adjusting the wall attachment state of the covered stent 100 on the small bend side to ensure that the stacking of the covered stent 100 on the proximal small bend side avoids the "bird's beak sign". After the wall attachment state of the covered stent 100 on the small bend side is adjusted, the second release allows the stent unit with the stent ring at the nearest end of the covered stent 100 on the large bend side to be released and attached to the vessel wall by the long rod 7221.

[0131] In an optional embodiment of this invention, the guide head 6 is provided with multiple axial limiting grooves 61 corresponding to the multiple forks 722 on its circumferential surface. The axial limiting grooves 61 penetrate the proximal end face (rear end face) of the guide head 6 to prevent the push tube 71 from rotating inside the outer sheath tube 4, ensuring the alignment accuracy of the small bend side of the covered stent 100. At the same time, the axial limiting grooves 61 can be used to squeeze and constrain the stent unit constrained by each fork 722, preventing the stent unit from accidentally slipping off the fork 722 before reaching the release bar, thereby improving the success rate of the operation.

[0132] In some optional embodiments of this example, the linear bending component 3 is a bending line. One end of the bending line facing the proximal end of the support body is fixedly connected to the support body, and the other end facing the distal end of the support body is a free end for pulling. The bending line passes through the film and frictionally engages with the perforations on the film through which the bending line passes. At this time, refer to... Figures 17 to 20 A pull ring 31 is integrally or fixedly connected to the free end of the bending cable; the conveyor 200 also includes a bending tube 8 and a bending cable 9; the bending tube 8 passes through the outer sheath tube 4. In the conveying state, the bending cable 9 passes through the pull ring 31 and confines the pull ring 31 inside the bending tube 8. By retracting the bending cable 9, the pull ring 31 can be released from the bending cable 9. In this optional embodiment, the bending tube 8 is preferably a capillary tube with a small radial dimension to reduce the overall diameter of the conveyor 200, making it easier for the conveyor 200 tubing to pass through tortuous blood vessels and improving the smoothness of delivery.

[0133] In this optional implementation, further optionally, as follows: Figure 18 As shown, the bending cable 9 is a flexible wire. After passing through the pull ring 31, it is folded in half and passed through the bending tube 8. The two ends of the bent cable 9 are exposed near the end (rear end) of the bending tube 8. Pulling the bending cable 9 backward can release the pull ring 31. Or, as... Figure 19As shown, the bending cable 9 is made of metal wire or alloy wire with a certain hardness. It passes through the bending tube 8, with one end exposed near the end (rear end) of the bending tube 8, and the other end passing through the pull ring 31 and bending back to form a bending head structure. When the head structure is inside the bending tube 8, it can restrain the pull ring 31. When the bending tube 8 is pushed forward or pulled back, it can be pulled backward to release the pull ring 31 when it is exposed outside the bending tube 8.

[0134] Third aspect

[0135] This embodiment provides a covered stent delivery system, including a covered stent 100 provided by any optional embodiment of the first aspect and a delivery device 200 provided by any optional embodiment of the second aspect.

[0136] The specific structure, usage, and achievable effects of the film-coated support 100 and the conveyor 200 can be obtained by referring to the relevant descriptions in the first and second aspects.

[0137] Finally, it should be noted that:

[0138] 1. In the above embodiments of this specification, "and / or" means that the first feature before "and / or" and the second feature after "and / or" include the following specific setting methods: (1) only the first feature is set, and the second feature is not set; (2) only the second feature is set, and the first feature is not set; (3) the first feature and the second feature are set at the same time;

[0139] 2. The above embodiments and optional implementations in this specification are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing optional implementations, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. Furthermore, it is emphasized again that, in the absence of conflict, the features of the embodiments and optional implementations in the embodiments in this specification can be combined with each other.

Claims

1. A covered stent, comprising a stent body, the stent body comprising a skeleton and a covering film connected to the surface of the skeleton, the skeleton comprising multiple stent rings spaced apart along the axial direction of the stent body; each stent ring having multiple V-shaped or arc-shaped stent units connected end to end along the circumference of the stent body; the radially opposite sides of the stent body being the large bend side and the small bend side of the stent body in a bent state; each pair of adjacent stent rings along the axial direction of the stent body forming a group, wherein in each group of stent rings, at least one stent unit of a stent ring located on the proximal side is stent unit one (1), and at least one stent unit of a stent ring located on the distal side is stent unit two (2). Its features are, The film-coated support (100) also includes a linear bending component (3); The linear bending member (3) is connected to the proximal small bend side of the stent body and extends from the proximal end of the stent body to the distal end of the stent body along the film of the stent body. The linear bending member (3) is configured to provide constraint on the film and / or stent unit of the stent body on the small bend side along its extension direction, so that at least one set of stent unit one (1) and stent unit two (2) of the stent ring are close to each other on the small bend side of the stent body, thereby creating wrinkles in the film between the corresponding stent unit one (1) and stent unit two (2). The side of the covering film facing the interior of the support body is defined as the inner side of the covering film, and the side of the covering film facing the exterior of the support body is defined as the outer side of the covering film. The linear bending component (3) is a bending line. One end of the bending line facing the proximal side of the support body is fixedly connected to the support body, and the other end of the bending line facing the distal side of the support body is a free end for pulling. The bending line passes through the film inside and out and is in frictional engagement with the perforations on the film through which the bending line passes. Alternatively, the linear bending component (3) is a spring, both ends of which are fixedly connected to the support body. The spring is inserted inside and outside the film and is configured to release elastic potential energy in a free state, so as to pull the support unit one (1) and support unit two (2) of at least one set of support rings between the two ends of the spring closer to each other. The linear bending component (3) passes through the film from the outside to the inside of the film at the proximal end of the distal end of the support unit one (1), and the linear bending component (3) passes through the film from the inside to the outside of the film at the proximal end of the distal end of the support unit two (2), so that the stacked support units after bending are stacked in an orderly manner when they are close to each other.

2. The covered stent according to claim 1, characterized in that, The linear bending component (3) is fixed or passes through the film at points located on the proximal side of the distal end of the corresponding support unit, or flush with the distal end of the corresponding support unit.

3. The covered stent according to claim 1, characterized in that, Along the axial direction of the covered support (100): the axial distance between the support unit one (1) and the support unit two (2) is h1, and the axial distance between the point where the linear bending component (3) passes through the covered film on the proximal side of the distal end of the support unit two (2) and the proximal end of the support unit two (2) is h2, satisfying: h2≥h1.

4. A conveyor, characterized in that, For delivering the covered stent (100) according to any one of claims 1-3; the delivery device (200) includes an outer sheath (4), a central tube (5), a guide head (6) and a rear release device (7); The guide head (6) is fixed to the distal end of the central tube (5), and the outer sheath (4) is fitted onto the outside of the central tube (5); The rear release device (7) includes a push tube (71) and a rear release claw (72). The push tube (71) passes through the outer sheath tube (4) and is fitted onto the outside of the central tube (5); The rear release claw (72) includes a connecting part (721) and a fork (722). The connecting part (721) is fixedly connected to the distal end of the push tube (71) and has a through hole that extends through the push tube (71) axially. The fork (722) includes at least one long rod (7221), the proximal end of which is fixed or integrally connected to the connecting part (721), and the distal end of which extends to the distal side of the connecting part (721); and the long rod (7221) is arranged radially along the push tube (71) on one side of the connecting part (721); The fork (722) also includes at least two short bars (7222); The proximal ends of all the forks (722) are fixedly connected to the connecting part (721) at uniform intervals along the circumference of the push tube (71), and the distal ends of all the forks (722) extend to the distal end side of the connecting part (721). The long rod (7221) and the short rod (7222) are respectively arranged on the two sides of the connecting part (721) that are radially opposite to each other along the push tube (71). The distal end of the long rod (7221) is located on the distal end side of the distal end of the short rod (7222). in: The distal surfaces of all the forks (722) are on the same inclined plane that is inclined relative to the radial cross-section of the push tube (71); or, the distal surfaces of each of the forks (722) are parallel to the radial cross-section of the push tube (71), the distal surfaces of all the long rods (7221) are on the same surface, and the distal surfaces of all the short rods (7222) are on the same surface.

5. The conveyor according to claim 4, characterized in that, The guide head (6) has multiple axial limiting grooves (61) on its circumferential surface, which correspond one-to-one with the multiple forks (722). The axial limiting grooves (61) penetrate the near end face of the guide head (6).

6. The conveyor according to claim 4, characterized in that, The linear bending component (3) is a bending line. One end of the bending line facing the proximal side of the support body is fixedly connected to the support body, and the other end facing the distal side of the support body is a free end for pulling. The bending line passes through the film and frictionally engages with the perforations on the film through which the bending line passes. The free end of the bending line is integrally or fixedly connected with a pull ring (31). The conveyor (200) also includes a bend-adjusting tube (8) and a bend-adjusting cable (9); The bending tube (8) passes through the outer sheath tube (4); In the conveying state, the bending cable (9) passes through the pull ring (31) and confines the pull ring (31) inside the bending tube (8). By retracting the bending cable (9), the pull ring (31) can be released from the bending cable (9).

7. A film-coated stent delivery system, characterized in that, It includes the covered support (100) according to any one of claims 1-3 and the delivery device (200) according to any one of claims 4-6.

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