A stent capable of accurate positioning and anti-displacement used at the intersection of cavities

Abstract

This invention discloses a precisely positioned and displacement-resistant stent for use at the junction of cavities, comprising a support stent and a positioning frame. The support stent supports the diseased junctional lumen; the positioning frame includes multiple positioning strips made of shape-memory metal. These positioning strips are linear when confined by the delivery sheath and coiled when released. The outer edge of the coiled structure includes a first part, a second part, and a third part connected sequentially. The first part forms a bent structure with the support stent and abuts against the junctional lumen wall. The second part is an arc-shaped portion with its opening facing the longitudinal axis of the support stent, thus opening the junctional lumen wall. Through the cooperation of the positioning strips and the support stent, precise positioning of the support stent at the junction is achieved. Simultaneously, the positioning strips have a small overall curvature and short longitudinal length, avoiding interference with other junctional cavities, making it particularly suitable for left common iliac vein stents, effectively preventing problems caused by excessive stent insertion or displacement.

Description

Technical Field

[0001] This invention belongs to the field of stent technology, and particularly relates to stents that need to be positioned at the junction of human cavities (blood vessels, esophagus, bile ducts, etc.); specifically, it is a stent that can be precisely positioned and prevents displacement, and is used at the junction of cavities. Background Technology

[0002] Various types of stents exist for human body cavities, such as biliary stents, esophageal stents, and vascular stents. These cavities intersect or connect with other cavities, thus creating the concept of "junctions." For example, the points where the iliac vein drains into the inferior vena cava, the bile duct drains into the duodenum, and the esophagus drains into the stomach are "junctions." When these junctions become narrowed or blocked, stents are placed to maintain the patency of the cavity. Precise positioning and prevention of displacement are crucial when placing stents at junctions. This presents challenges for both stent design and the operator's skills.

[0003] Take the example of the left and right iliac veins draining into the inferior vena cava. The inferior vena cava and the two iliac veins converge at a certain angle. When the iliac veins (especially the left common iliac vein) experience severe stenosis / occlusion, leading to intractable lower extremity venous return obstruction, a stent needs to be precisely placed at the site of the iliac vein lesion. Excessive insertion of the iliac vein stent into the inferior vena cava can affect blood flow on the contralateral side and even lead to secondary thrombosis. If the iliac vein stent is placed distal to the stenotic segment, restenosis may occur.

[0004] Regarding the issue of iliac vein stent positioning, the existing technology CN115245412A - an anti-reflux venous stent with a fixed valve - uses an enlarged stent section at the intersection that is larger than the outer wall of the stent. However, this method of positioning at the junction of the iliac vein and the inferior vena cava requires a relatively long stent. When in use, the long stent is placed in the inferior vena cava to play a positioning role, but the long, enlarged stent section can easily interfere with the blood flow of the iliac vein on the other side. Moreover, it is particularly easy to cause interference when performing subsequent surgeries through the iliac vein or inferior vena cava.

[0005] The existing technology CN211156500U-positionable vascular stent is a petal-shaped stent. Although this stent can position itself, its edge contacts the blood vessel, which can easily damage the vessel wall. Moreover, the larger petal-shaped stent portion has a stronger obstruction force on the blood flow on the opposite side, which can significantly affect the blood flow of the contralateral iliac vein due to this design. Summary of the Invention

[0006] To address the aforementioned technical issues, existing stent positioning structures used in the junctional zone can easily affect blood flow in the main branch or other junctional lumens. The core reason for this impact is the excessive extension distance of the positioning structure. These structures are typically positioned around the outer wall of the stent in a 360-degree arc, and even when not, their angle of coverage over the main stent is significant. This inevitably affects blood flow in other junctional lumens. Therefore, a thinner positioning structure is needed. However, if this thinner structure is a strip with minimal curling, similar to the enlarged stent portion or the curled cross-section of a petal in existing technologies, it carries the risk of piercing the vessel wall and causing damage.

[0007] The specific technical solution is as follows: a stent that can be accurately positioned and prevents displacement, used at the junction of cavities, which includes a support bracket and a positioning bracket.

[0008] The support bracket is used to support one of the manifold cavities; The positioning frame is used to position the first end of the support bracket at the junction position and is set in the main branch cavity of the junction cavity during use; it includes multiple positioning strips arranged around the support bracket, the positioning strips are made of shape memory metal, and the positioning strips have two states: the first state is a linear state and the second state is a curled state; the positioning strips are in a linear state when confined within the delivery sheath; and in a curled state after the confinement of the delivery sheath is released.

[0009] The positioning strip includes a coiled structure, which achieves positioning by applying pressure and / or support to the vessel wall. The outer edge of the coiled structure includes a first part, a second part, and a third part connected in sequence. The first part forms a bent structure with the outer wall of the stent. When the bent structure is in function, the first part abuts against the bent lumen wall at the junction of the confluent lumens without damaging the lumen wall. The second part is further away from the longitudinal axis of the stent than the first and third parts, and the second part is an arc-shaped portion with its opening facing the longitudinal axis of the stent. When the second part is in function, it is used to open up the lumen wall at the junction of the confluent lumens. One part of the first part and one part of the second part of each coiled positioning strip are in function.

[0010] Furthermore, the number of positioning strips is 3-6; the overall width of all positioning strips is less than 1 / 18 of the circumference of the support stent; this arrangement can avoid interference of the positioning strips with blood flow in other confluent lumens.

[0011] Furthermore, the distance from the farthest point of the second part from the longitudinal axis of the support bracket to the longitudinal axis of the support bracket is L; the radius of the support bracket is R; L:R = 1.2-1.3:1.

[0012] Furthermore, the length of the coiled structure along the longitudinal axis of the support stent is less than one-third of the diameter of the smallest lumen among the multiple converging lumens; when the positioning stent is used for the iliac vein and the inferior vena cava, the height of the coiled structure along the longitudinal axis ranges from 3 to 5 mm.

[0013] Furthermore, a first elastic expansion ring is provided at the first end of the support bracket, and a second elastic expansion ring is provided at the second end of the positioning frame. The first and second elastic expansion rings are combined and connected, allowing the support bracket and the positioning frame to be assembled together. Positioning strips are evenly distributed on the second elastic expansion rings, used to deliver each positioning strip to the accurate position and maintain it in the required position by utilizing the elastic force of the second elastic expansion rings. Alternatively, the positioning strips include fixing strips, which are evenly fixed inside the support bracket; the fixing strips are welded to the inner wall of the support bracket. The diameter of the fixing strip is less than or equal to one-sixth of the diameter of the support bracket. This size setting ensures the fixing effect without affecting the pipe diameter of the support bracket.

[0014] Furthermore, the fixing strip is provided with an anchoring strip that is inclined towards the first end of the support bracket to prevent the support bracket from moving towards the intersection. It works in conjunction with the positioning frame to play a bidirectional positioning role, so that the support bracket is stably positioned and will not move in any direction.

[0015] Furthermore, the coiled structure is a non-closed coiled loop with its opening facing the longitudinal axis of the support bracket. The first part is connected to the support bracket, and the second and third parts are connected in sequence. The non-closed coiled loop can be a semi-circular loop or an elliptical loop, or other similar irregular coiled loops. This method is a relatively simple structure.

[0016] Alternatively, the coiled structure can be a spiral structure; the third part of the spiral structure is connected to the second elastic support ring or fixing strip, the first part is the lower part of the outermost ring of the spiral structure; the second part is the outer part of the outermost ring of the spiral structure. By setting the spirals, each part can be formed more perfectly, and by forming each part with circular parts, damage to the lumen can be avoided to the greatest extent.

[0017] Beneficial effects The first part of the positioning strip and the support stent form a bent structure that abuts against the bent cavity wall at the junction. Combined with the second part, it opens up the cavity wall at the junction of the confluence vessels. The two-way cooperation achieves precise fixation of the support stent at the junction, effectively preventing the support stent from moving into the deeper part of the lumen and eliminating problems such as support failure and restenosis in narrowed areas caused by displacement. It is especially suitable for scenarios requiring precise positioning, such as the junction of the iliac vein and the inferior vena cava.

[0018] The positioning strip is made of shape memory metal, and the outer edge of the coiled structure is smooth. The first part will not cause damage when it comes into contact with the vessel wall, and the free end of the third part is designed to avoid piercing the side wall of the blood vessel. At the same time, it abandons the design of the enlarged stent segment and petal-shaped structure in the existing technology, which reduces the contact area and contact pressure between the positioning structure and the blood vessel wall, fundamentally reducing the risk of blood vessel wall damage and improving the safety of stent implantation.

[0019] By controlling the number of positioning strips to 3-6, and ensuring the overall curvature is less than 20°, the positioning structure avoids 360° encirclement of the support stent, reducing obstruction of other converging vessels. At the same time, the length of the coiled structure along the longitudinal axis of the support stent is relatively short, not exceeding one-third of the smallest lumen diameter in the converging lumen (3mm-5mm when used in the iliac vein and inferior vena cava), which avoids excessive extension into other lumens. This effectively solves the problem of blood flow interference caused by the excessive extension distance and wide coverage angle of the positioning structure in existing positioning stents, ensuring unobstructed blood flow to the main branch and other converging vessels.

[0020] The positioning frame and the support stent are connected by a combination of first and second elastic support rings, which reduces the assembly difficulty of the two. The elastic support ring is ≤1mm wide and does not affect the overall structure of the stent. The curled structure of the positioning strip can adopt a non-closed curled ring or a vortex structure. The vortex structure has no gap between adjacent two turns, which can avoid the guide wire from entering the gap and interfering with the operation in subsequent surgery, thus improving the convenience of stent implantation and subsequent diagnosis and treatment operations.

[0021] By setting an anchoring strip inclined towards the first end inside the support bracket, bidirectional positioning can be achieved in conjunction with the positioning frame, preventing the support bracket from moving arbitrarily towards the junction or deep into the junction cavity, further improving positioning stability and ensuring that the bracket can effectively play its supporting role for a long time.

[0022] By controlling the ratio of the distance L between the farthest end of the second part and the longitudinal axis of the support stent to the diameter R of the support stent at 1.2-1.3:1, the positioning frame can be stably fixed at the junction. At the same time, it can be adapted to junction lumens of different diameters. It is not only suitable for the junction of the iliac vein and the inferior vena cava, but can also be extended to other junction lumens or human body cavity junction positioning scenarios. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an iliac vein stent positioned using an enlarged stent portion, based on existing technology. Figure 2 A schematic diagram of the overall structure of an embodiment where the curled structure is a vortex structure and the fixing strip is provided with an anchoring strip; Figure 3A is a schematic diagram of a positioning strip with a curled and vortex structure. A is a schematic diagram of a positioning strip without a fixing strip. B is a schematic diagram of a positioning strip with an anchoring strip. Figure 4 A schematic diagram of the overall structure of an embodiment where the coiled structure is a vortex structure and the support structure and positioning frame are combined by an elastically open ring; Figure 5 A schematic diagram of a positioning frame structure with a coiled, vortex-like structure and an elastic support ring; Figure 6 A schematic diagram showing the placement of a positioning stent at the iliac vein location; Figure 7 A schematic diagram of a positioning frame installed in a vertically intersecting human body cavity; Figure 8 A schematic diagram of the overall structure of an embodiment where the curled structure is a non-closed curled loop; Figure 9 A schematic diagram showing the structure in which the positioning bracket is confined within the delivery sheath; Figure 10 A schematic diagram of a positioning frame structure with a non-closed coiled ring and a fixing strip; Figure 11 A schematic diagram of a positioning strip structure, which is a non-closed coiled ring with a fixing strip and an anchoring strip on the fixing strip; Figure 12 A schematic diagram of the overall structure of an embodiment where the curled structure is a non-closed curled ring and the support bracket and positioning frame are combined by an elastically open ring; Figure 13 This is a partially enlarged structural diagram of the combination of the positioning frame and the support frame, where the curled structure is a non-closed curled ring and the support bracket and the positioning frame are combined by an elastically open ring. Figure 14 The diagram shows a partially enlarged view of the connecting hole and the connecting ring. A shows a partially enlarged view of the positions of the first and second elastic support rings with the connecting hole; B shows a partially enlarged view of the positions of the first and second elastic support rings with the connecting ring.

[0024] Explanation of main figure symbols 1. Support bracket; 11. First elastic expansion ring; 2. Positioning frame; 21. Positioning strip; 211. Coiled structure; 2111. First part; 2112. Second part; 2113. Third part; 212. Second elastic expansion ring; 213. Fixing strip; 31. Connecting hole; 32. Connecting ring; 4. Anchoring strip; 5. Iliac vein; 6. Inferior vena cava; 7. Expanded support portion; 8. Delivery sheath. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In this document, “illustrative” means “serving as an example, illustration or description”, and any illustration or implementation described herein as “illustrative” should not be construed as a more preferred or advantageous technical solution.

[0027] To keep the drawings concise, only the parts relevant to this application are shown schematically in each drawing, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, in some drawings, only one of the components with the same structure or function is shown schematically, or only one of them is labeled.

[0028] In this document, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or stated, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] refer to Figure 1 The existing technology for iliac vein stents in the iliac vein 5 uses a large, enlarged stent portion 7 to position the iliac vein stent; however, the enlarged stent portion 7 excessively enters the inferior vena cava 6, interfering with blood flow in the contralateral iliac vein 5 and hindering subsequent procedures. The following describes the implementation of the stent using the iliac vein stent as the main embodiment.

[0030] refer to Figures 2-13 A stent that can be precisely positioned and prevents displacement, used at the junction of cavities, comprising a support bracket 1 and a positioning bracket 2.

[0031] The support stent 1 is used to support the iliac vein 5. Its configuration is consistent with the support part of the traditional iliac vein stent. It is made of medical nickel-titanium shape memory alloy and has a mesh structure. It is used to implant into the lumen of the iliac vein 5. The diameter R of the support stent 1 is selected according to the clinical diameter of the iliac vein 5, usually 12-16 mm.

[0032] The positioning frame 2 is used to position the first end of the support stent 1 at the junction of the inferior vena cava 6 and the iliac vein 5, and is placed inside the inferior vena cava 6 during use; the positioning frame 2 is connected to the first end of the support stent 1; the positioning frame 2 includes four positioning strips 21 arranged around the support stent 1, the positioning strips 21 are made of shape memory metal, and the positioning strips 21 have two states, the first state being a linear state, i.e., the state before release, see reference. Figure 9 The second state is the curled state, which is the state after release. (See reference...) Figure 2 , Figure 4 and Figure 8 and Figure 12 The positioning strip 21 is linearly confined within the delivery sheath 8; after the confinement effect of the delivery sheath 8 is released, it curls up. In specific implementations, 3-6 positioning strips 21 can also be set.

[0033] The curled positioning strip 21 includes a curled structure 211, which achieves its positioning function by applying pressure and / or supporting force to the blood vessel wall; for details, please refer to... Figure 3 and Figure 11 The outer edge of the curled structure 211 includes a first part 2111, a second part 2112, and a third part 2113 connected in sequence. The first part 2111 forms a bent structure with the outer wall of the support bracket 1. When the bent structure is in function, the first part 2111 abuts against the bent cavity wall at the junction of the confluence of the tubes without damaging the cavity wall. The second part 2112 is farther away from the longitudinal axis of the support bracket 1 than the first part 2111 and the third part 2113. The second part 2112 is an arc-shaped part with its opening facing the longitudinal axis of the support bracket 1. When the second part 2112 is in function, it is used to open the cavity wall at the junction. One part of the first part 2111 and one part of the second part 2112 of each curled positioning strip 21 is in function.

[0034] refer to Figure 6 The bending structure formed by the combination of the first part 2111 of some of the positioning strips 21 and the support bracket 1 makes the first part 2111 abut against the bent cavity wall at the junction, while the second part 2112 of the other positioning strips 21 opens up the cavity wall at the junction.

[0035] In one specific implementation, for example Figure 7Then, the bending structure formed by the combination of the first part 2111 of all the positioning strips 21 and the support bracket 1 plays its role. Regardless of the method, the positioning strips 21 with different forces cooperate to effectively position the first end of the support bracket 1 at the junction, avoiding the risk of the support bracket 1 moving out of the narrow position at the junction due to movement towards one of the junction lumens where the bracket is placed. The overall width of all the positioning strips 21 is less than 1 / 18 of the circumference of the support bracket 1; this setting can avoid the positioning strips 21 interfering with the blood flow of other junction lumens. Of course, in specific implementation, the number of positioning strips 21 is limited to 3-6.

[0036] refer to Figure 3 and Figure 11 The second part 2112 is an arc-shaped portion facing the axis of the support bracket 1, which can effectively avoid damage to the side wall at the junction. The first part 2111 and the support bracket 1 form a hook-like structure with a curled structure. In use, the positioning frame 2 is first placed in the inferior vena cava 6 in front of the junction. The positioning frame 2 is released in the inferior vena cava 6. Then, the positioning frame 2 is pulled towards the deep part of the iliac vein 5. At this time, the first part 2111 is against the junction of the two side walls of the junction, so that the pulling action is terminated. The second part 2112 also has a certain opening force on the side wall of the iliac vein 5 at the junction, thereby generating a certain anchoring force. Together with the first part 2111, it fixes the position of the positioning frame 2, thereby finally achieving the positioning of the opened support bracket 1 by using the positioning frame 2.

[0037] refer to Figure 12 The distance from the farthest point of the second part 2112 to the longitudinal axis of the support 1 is L; the radius of the support 1 is R. In order to ensure that the second part 2112 is stably locked at the intersection position without causing too much interference to the blood flow of the iliac vein 5 on the opposite side, L:R is set to 1.2~1.3; for example, if R is 6mm, then the range of L is 7.2-7.8mm.

[0038] A more preferred embodiment is as follows: when the positioning stent is used for the iliac vein 5 and the inferior vena cava 6, the height range of the coiled structure 211 along the longitudinal axis is 3-5 mm; when implementing this method in other fields, the length of the coiled structure 211 along the longitudinal axis of the support stent 1 should be less than one-third of the smallest lumen diameter among the multiple converging lumens; this length setting can ensure that only a small section of the vessel wall is affected, and the coordination between the length of the coiled structure 211 and the length L can ensure the stable positioning of the coiled structure 211. Furthermore, because the length setting along the longitudinal axis can prevent the coiled structure 211 from excessively entering other lumens through the converging point and affecting the operation of other lumens.

[0039] A more preferred embodiment is that, since the positioning frame 2 and the support bracket 1 need to maintain an effective position and dimensional relationship after being opened, ensuring that the two structures maintain the required state after being opened is a key factor in ensuring that the device can function properly. (Refer to...) Figure 4 , Figure 5 and Figures 12-14 The first method involves providing supplementary opening force by setting up elastic support rings. Specifically, a first elastic support ring 11 is set at the first end of the support bracket 1, and a second elastic support ring 212 is set at the second end of the positioning frame 2. The first elastic support ring 11 and the second elastic support ring 212 are combined and connected, allowing the support bracket 1 and the positioning frame 2 to be assembled together. Positioning strips 21 are evenly arranged on the second elastic support ring 212, which are used to deliver each positioning strip 21 to the accurate position and maintain it in the required position with the elastic force of the second elastic support ring 212. The above-mentioned setting of two elastic support rings can reduce the difficulty of assembling the positioning frame 2 and the support bracket 1. In use, it is only necessary to connect the first elastic support ring 11 and the second elastic support ring 212 to achieve assembly. The ring width of the first elastic support ring 11 and the second elastic support ring 212 is less than or equal to 1mm, and this distance can effectively avoid the impact on the overall support structure. In specific assembly, welding or bio-adhesive can be used. A more preferred embodiment is that connecting holes 31 are provided at the same position on the side walls of both the first elastic support ring 11 and the second elastic support ring 212. The connecting ring 32 extends into the connecting hole 31 to connect the positioning frame 2 and the support bracket 1. This arrangement can effectively achieve the assembly of the positioning frame 2, and also allows for a certain gap between the positioning frame 2 and the support bracket 1, forming a certain buffer. Of course, in specific implementations, the first elastic support ring and the second elastic support ring 212 can also be integrally set.

[0040] Or, refer to Figure 2 , Figure 3 , Figure 8 , Figure 10 and Figure 11 The second method involves extending the positioning strip 21 inside the support bracket 1, allowing it to open with the force of the support bracket 1. Specifically, the positioning strip 21 includes a fixing strip 213, which is uniformly fixed inside the support bracket 1 and welded to the inner wall of the support bracket 1. The diameter of the fixing strip 213 is less than or equal to one-sixth of the diameter of the support bracket 1. This size ensures a secure fixation without affecting the diameter of the support bracket 1.

[0041] A more preferred embodiment is described in reference to... Figure 2 , Figure 3 and Figure 11Anchor bars 4, inclined towards the first end of the support bracket 1, are provided on the fixing strip 213 to prevent the support bracket 1 from moving towards the intersection. Working in conjunction with the positioning frame 2, they provide bidirectional positioning, ensuring the support bracket 1 is stably positioned and will not move in either direction. The anchor bars 4 extend from the side wall of the support bracket 1. It should be noted that when the support bracket 1 and the positioning frame 2 are combined via an elastic support ring, refer to... Figure 12 The anchoring strip 4 is directly attached to the side wall of the support stent 1. The end of the anchoring strip 4 is blunted, and the maximum distance between the anchoring strip 4 and the side wall in the released state is 3-5 mm. This distance can avoid damage to the blood vessel wall caused by the anchoring strip 4.

[0042] A more preferred embodiment is defined in the specific implementation of the curled structure. (See reference) Figures 1-7 The coiled structure is a vortex structure with spiraling loops. The third part 2113 of the vortex structure is connected to the second elastic support ring 212 or the fixing strip 213. The first part 2111 is the lower part of the outermost ring of the vortex structure; the second part 2112 is the outer part of the outermost ring of the vortex structure. The vortex arrangement allows for a more perfect formation of each part, and the circular shape of each part minimizes damage to the lumen. There are no gaps between adjacent loops of the vortex structure, resulting in a solid circular disc. This design aims to prevent the guidewire from entering the gaps in the vortex structure and interfering with the surgical procedure when re-entering this position for surgery.

[0043] refer to Figures 8-13 The coiled structure is a non-closed coiled ring with its opening facing the longitudinal axis of the support bracket 1. The first part 2111 is connected to the support bracket 1, and the second part 2112 and the third part 2113 are connected in sequence. The non-closed coiled ring is a semi-circular ring or an elliptical ring, or other similar irregular coiled rings. This is a relatively simple structure. The third part 2113 of the non-closed coiled ring is free, and the free end is perpendicular to the longitudinal axis of the support bracket 1 or coiled in a direction away from the longitudinal axis of the support bracket 1. This setting can ensure that the non-closed coiled ring formed after the restriction of the delivery sheath 8 is removed does not cause unnecessary damage to the lumen wall.

[0044] The method of use is as follows: First, construct the operating path using a guidewire. Then, insert the stent-equipped delivery sheath 8 along the operating path into the inferior vena cava 6. By retracting the delivery sheath 8, position the positioning frame 2 at the intersection of the iliac vein 5 and the inferior vena cava 6. Then, release the positioning frame 2 first, and then pull the entire assembly to make the first part 2111 of the positioning strip 21 abut against the inner wall of the intersection, while the second part 2112 of the other positioning strip 21 opens the wall at the intersection, thus positioning the positioning frame 2. Then release... When the support of the stent 1 is insufficient, a balloon can be used to expand it to ensure that the stent 1 can stably play a supporting role in the iliac vein 5. Of course, in the implementation method with anchor strip 4, the anchor strip 4 is also locked on the blood vessel wall as the stent 1 is released. After the stent is fully released, the positioning function of the positioning frame 2 can effectively prevent it from moving towards the deep part of the iliac vein 5, so that the narrow segment of the iliac vein 5 at the confluence is opened up, and the setting of anchor strip 4 can also prevent it from moving towards the inferior vena cava 6.

[0045] The above description is merely a specific embodiment of this application. Under the guidance of the above teachings, those skilled in the art can make other improvements or modifications based on the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of this application, and the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A stent that can be precisely positioned and prevents displacement, used at the junction of cavities, comprising: Support stents are used to support the confluence of diseased lumens; A positioning frame is used to position the first end of the support bracket at the junction, and is placed in the lesion section of the junction lumen during use to effectively support the lesion. It includes multiple positioning strips arranged around the support bracket. The positioning strips are made of shape memory metal and have two states: a first state is a linear state and a second state is a curled state. The positioning strips are in a linear state when confined within the delivery sheath and in a curled state after the confining effect of the delivery sheath is released. The positioning strip includes a coiled structure, which achieves positioning by applying pressure and / or support to the vessel wall. The outer edge of the coiled structure includes a first part, a second part, and a third part connected in sequence. The first part forms a coiled structure with the outer wall of the support stent. When the coiled structure is in function, the first part abuts against the lumen wall at the junction of the confluent lumens without damaging the lumen wall. The second part is further away from the longitudinal axis of the support stent than the first part and the third part, and the second part is an arc-shaped portion with its opening facing the longitudinal axis of the support stent. When the second part is in function, it is used to open up the lumen wall at the junction of the confluent lumens. Each coiled positioning strip has one portion of the first part or one portion of the second part in function.

2. The bracket according to claim 1, characterized in that, The number of positioning strips is 3-6; The overall width of all the positioning strips is less than 1 / 18 of the circumference of the support bracket 1.

3. The bracket according to claim 1, characterized in that, The distance from the farthest point of the second part from the longitudinal axis of the support bracket to the longitudinal axis of the support bracket is L; the radius of the support bracket is R; L:R = 1.2-1.3; Preferably, the length of the coiled structure along the longitudinal axis of the support bracket is less than one-third of the diameter of the smallest lumen among the multiple converging lumens; Preferably, when the positioning stent is used for the iliac vein and the inferior vena cava, the height of the coiled structure along the longitudinal axis ranges from 3mm to 5mm.

4. The bracket according to claim 1, characterized in that, The first end of the support bracket is provided with a first elastic expansion ring, and the second end of the positioning frame is provided with a second elastic expansion ring. The first elastic expansion ring and the second elastic expansion ring are combined and connected so that the support bracket and the positioning frame are assembled together. The positioning strips are evenly arranged on the second elastic expansion ring, and are used to deliver each positioning strip to the accurate position and maintain it in the required position by means of the elastic force of the second elastic expansion ring.

5. The bracket according to claim 4, characterized in that, It also includes a connecting ring; The ring widths of the first elastic expansion ring and the second elastic expansion ring are less than or equal to 1 mm; Preferably, the sidewalls of the first elastic support ring and the second elastic support ring are provided with connecting holes at the same position, and the connecting ring extends into the connecting hole to connect the positioning frame and the support bracket.

6. The bracket according to claim 1, characterized in that, The positioning strip includes a fixing strip, which is uniformly fixed inside the support bracket; the fixing strip is welded to the inner wall of the support bracket. Preferably, the diameter of the fixing strip is less than or equal to one-sixth of the diameter of the support bracket.

7. The stent according to claim 6, characterized in that, An anchoring bar inclined toward the first end of the support bracket is provided on the fixing bar to prevent the support bracket from moving toward the intersection and to cooperate with the positioning frame to play a bidirectional positioning role.

8. The bracket according to claim 1, characterized in that, The coiled structure has a non-closed coiled loop with an opening facing the longitudinal axis of the support bracket. The first part is connected to the support bracket, and the second part and the third part are connected in sequence. Preferably, the non-closed coiled loop is a semi-circular loop or an elliptical loop, or an irregular coiled loop.

9. The bracket according to claim 8, characterized in that, The third portion of the non-closed coiled ring is free, and the free end is either perpendicular to the longitudinal axis of the support bracket or coiled in a direction away from the longitudinal axis of the support bracket.

10. The stent according to claim 1, characterized in that, The coiled structure is a vortex structure with spiral winding; the third part of the vortex structure is connected to the second elastic support ring or the fixing strip; the first part is the lower part of the outermost ring of the vortex structure; the second part is the outer part of the outermost ring of the vortex structure. Preferably, there is no gap between adjacent turns of the vortex structure.

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