An extravascular stent

Abstract

The present invention discloses an extracorporeal vascular stent, belonging to the technical field of vascular stents, which includes a first fixing ring, a second fixing ring, a third fixing ring, a connecting rod assembly, a first telescopic rod and a second telescopic rod; the first fixing ring and the second fixing ring are respectively adapted to be sleeved on the outer periphery of the first blood vessel upstream and downstream of the anastomosis, and the third fixing ring is adapted to be sleeved on the outer periphery of the second blood vessel. The connecting rod assembly is rigidly connected between the first fixing ring and the second fixing ring; the first telescopic rod is connected between the first fixing ring and the third fixing ring; the second telescopic rod is connected between the second fixing ring and the third fixing ring; both the first telescopic rod and the second telescopic rod are elastic and axially telescopic telescopic rod bodies. For this extracorporeal vascular stent, the axially telescopic first telescopic rod and second telescopic rod are used to support the second blood vessel. When the fluid pressure in the second blood vessel is relatively high, the second blood vessel can swing relative to the predetermined angle, avoiding excessive blood flow pressure on the wall of the second blood vessel.

Description

Technical Field

[0001] The present invention relates to the technical field of vascular stents, and particularly to an external vascular stent. Background Art

[0002] Patients in the end stage of kidney disease generally need to undergo frequent hemodialysis to remove toxins from the blood and maintain an appropriate homeostasis. To effectively remove toxins, the blood must flow through the hemodialysis machine at a relatively large blood flow rate. This relatively large blood flow rate is optimally achieved by creating a permanent vascular access site that includes an arteriovenous (AV) anastomosis; among them, the vein is attached to the artery to form a large-flow shunt or fistula, which is usually referred to as an AV fistula. Due to the excellent patency of the AV fistula, low complication rate, lower cost of the healthcare system, and low risk of patient death, it is widely used for hemodialysis vascular access.

[0003] When forming an AV fistula, usually the vein is directly attached to the artery, which will cause blood flow disorders at the arteriovenous anastomosis, or a sharp change in the blood pressure and blood circulation conditions on the venous side. This will generate excessive stress in the blood vessel wall of the arteriovenous anastomosis and the downstream vein, leading to pathological intimal hyperplasia, and sometimes causing blockage, stenosis, etc.; to solve the above problems, an external vascular stent is proposed to be provided on the vascular anastomosis to alleviate the excessive blood flow change in the vein at the initial stage of anastomosis formation. However, the existing external vascular stent has a complex structure and is inconvenient to install, and cannot alleviate the pressure borne by the venous blood vessel during blood flow fluctuations. Summary of the Invention

[0004] In view of this, the present invention provides an external vascular stent to solve the problems of the existing external vascular stent having a complex structure, being inconvenient to install, and being unable to alleviate the pressure borne by the venous blood vessel during blood flow fluctuations.

[0005] To solve the above technical problems, the technical solution of the present invention is as follows:

[0006] An external vascular stent, comprising:

[0007] A fixed stent, comprising a first fixing ring, a second fixing ring, and a connecting rod assembly rigidly connected between the first fixing ring and the second fixing ring; wherein, the first fixing ring is adapted to be sleeved on the outer periphery of a first blood vessel upstream of the anastomosis, the second fixing ring is adapted to be sleeved on the outer periphery of the first blood vessel downstream of the anastomosis, and the anastomosis is the position where a second blood vessel is attached to the first blood vessel;

[0008] The movable bracket includes a third fixing ring, a first telescopic rod, and a second telescopic rod; the third fixing ring is adapted to be sleeved around the periphery of the second blood vessel; one end of the first telescopic rod is connected to the first fixing ring, and the other end is connected to the third fixing ring; one end of the second telescopic rod is connected to the second fixing ring, and the other end is connected to the third fixing ring;

[0009] The first telescopic rod and the second telescopic rod are both elastic and axially extendable telescopic rods; the second blood vessel is suitable for maintaining a predetermined angle with the first blood vessel under the combined force of the first telescopic rod and the second telescopic rod; when the second blood vessel is subjected to an external force other than the first telescopic rod and the second telescopic rod, the first telescopic rod and the second telescopic rod allow the second blood vessel to swing up and down relative to the predetermined angle.

[0010] Furthermore, the first fixing ring and the second fixing ring are both open rings with an opening at one end and arranged circumferentially.

[0011] Furthermore, the third fixing ring is a C-shaped ring having an opening at one end and being circumferentially arranged. The C-shaped ring itself is elastic and is suitable for clamping the second blood vessel located inside the C-shaped ring through its own elastic deformation.

[0012] Furthermore, the third fixing ring is made of stainless steel.

[0013] Furthermore, the connecting rod assembly includes a first rigid rod and a second rigid rod arranged opposite to each other, one end of the first rigid rod is rigidly connected to the first fixing ring, and the other end is rigidly connected to the second fixing ring, and one end of the second rigid rod is rigidly connected to the first fixing ring, and the other end is rigidly connected to the second fixing ring.

[0014] Furthermore, the first fixing ring and the second fixing ring are both provided with a card slot, and both ends of the first rigid rod and the second rigid rod are provided with a card block that can be embedded in the corresponding card slot; the part of the card block embedded in the card slot has the same shape as the card slot to achieve a rigid connection between the two.

[0015] Furthermore, the first telescopic rod includes a first outer tube, a first inner rod, and a first elastic member; one end of the first outer tube is hinged to the first fixing ring, one end of the first inner rod extends into the first outer tube and is telescopically arranged along the axial direction of the first outer tube, the other end of the first inner rod is hinged to the third fixing ring, and the first elastic member is arranged in the first outer tube, with one end elastically abutting against the first inner rod.

[0016] The second telescopic rod includes a second outer tube body, a second inner rod body, and a second elastic member; one end of the second outer tube body is hinged to the second fixing ring, one end of the second inner rod body extends into the second outer tube body and is telescopically arranged along the axial direction of the second outer tube body, the other end of the second inner rod body is hinged to the third fixing ring, and the second elastic member is arranged in the second outer tube body and elastically abuts against the second inner rod body at one end.

[0017] Further, when the second blood vessel and the first blood vessel are maintained at a predetermined angular position, the resultant force of the supporting force of the first telescopic rod on the second blood vessel and the supporting force of the second telescopic rod on the second blood vessel is balanced with the gravity of the part of the second blood vessel near the anastomosis.

[0018] Further, when the second blood vessel and the first blood vessel are maintained at a predetermined angular position, the supporting force of the first telescopic rod on the second blood vessel is less than the supporting force of the second telescopic rod on the second blood vessel.

[0019] Further, the shortest length of the first telescopic rod during the telescopic process is greater than the maximum length of the second telescopic rod during the telescopic process.

[0020] The technical solution of the present invention has the following advantages: This extracorporeal blood vessel stent is composed of a first fixing ring, a second fixing ring, a third fixing ring, a connecting rod assembly, a first telescopic rod, and a second telescopic rod. The overall structure is simple and can provide reliable external support for the first blood vessel and the second blood vessel. When installing the extracorporeal blood vessel stent, first clamp the third fixing ring on the outer periphery of the second blood vessel, then respectively sleeved the first fixing ring and the second fixing ring on the first blood vessel upstream and downstream of the anastomosis, and finally use the connecting rod assembly to rigidly connect the first fixing ring and the second fixing ring together, that is, complete the installation of the extracorporeal blood vessel stent on the outer periphery of the first blood vessel and the second blood vessel. The installation of the extracorporeal blood vessel stent is convenient and fast. Moreover, since both the first telescopic rod and the second telescopic rod are elastic and axially telescopic telescopic rod bodies, the second blood vessel is maintained at a predetermined angular position with the first blood vessel under the combined action of the first telescopic rod and the second telescopic rod. When the fluid pressure in the second blood vessel is relatively large, the second blood vessel can swing relative to the predetermined angular position, which can alleviate the excessive blood flow change of the second blood vessel in the initial stage of the formation of the anastomosis part and avoid lesions such as intimal thickening due to excessive blood flow pressure on the wall of the second blood vessel. Description of the Drawings

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 This is a schematic three-dimensional structure diagram of the extracorporeal blood vessel stent in the embodiment of the present invention. The arrow direction in the figure is the blood flow direction in the first blood vessel.

[0023] Figure 2 This is the front view of the extracorporeal blood vessel stent in the embodiment of the present invention.

[0024] Figure 3 This is the cross-sectional view of the extracorporeal blood vessel stent in the embodiment of the present invention.

[0025] Explanation of reference numerals: 100, the first blood vessel; 200, the second blood vessel; 300, anastomosis; 1, the first fixing ring; 2, the second fixing ring; 3, the third fixing ring; 4, the first rigid rod; 5, the second rigid rod; 6, the first telescopic rod; 61, the first outer tube body; 62, the first inner rod body; 63, the first elastic member; 7, the second telescopic rod; 71, the second outer tube body; 72, the second inner rod body; 73, the second elastic member. Detailed implementation manners

[0026] Next, the technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0028] As Figures 1 - 3 shown, an extracorporeal blood vessel stent is mainly used for external support of blood vessels, especially for external support at the anastomosis of arterial and venous blood vessels. The extracorporeal blood vessel stent mainly includes a fixed stent and a movable stent.

[0029] Figure 1 The arrow direction in Figure 1 is the blood flow direction in the first blood vessel 100. An incision is provided on the wall of the first blood vessel 100. The open end of the second blood vessel 200 is sutured to the first blood vessel 100 and covers the incision on the first blood vessel 100, so that the blood flow upstream of the first blood vessel 100 can flow into the second blood vessel 200. The position where the second blood vessel 200 is attached to the first blood vessel 100 is the anastomosis 300. The upstream and downstream of the anastomosis 300 are defined according to the blood flow direction in the first blood vessel 100.

[0030] As Figure 1 and Figure 2 shown, the fixed bracket includes a first fixing ring 1, a second fixing ring 2 and a connecting rod assembly, and the connecting rod assembly is rigidly connected between the first fixing ring 1 and the second fixing ring 2. Among them, the first fixing ring 1 is adapted to be sleeved on the outer periphery of the first blood vessel 100 upstream of the anastomosis 300, and the second fixing ring 2 is adapted to be sleeved on the outer periphery of the first blood vessel 100 downstream of the anastomosis 300. The movable bracket includes a third fixing ring 3, a first telescopic rod 6 and a second telescopic rod 7, and the third fixing ring 3 is adapted to be sleeved on the outer periphery of the second blood vessel 200. One end of the first telescopic rod 6 is hinged to the first fixing ring 1 and the other end is hinged to the third fixing ring 3, and one end of the second telescopic rod 7 is hinged to the second fixing ring 2 and the other end is hinged to the third fixing ring 3. Both the first telescopic rod 6 and the second telescopic rod 7 are elastic and axially telescopic telescopic rod bodies. The second blood vessel 200 is adapted to be kept at a predetermined angle with the first blood vessel 100 under the combined action of the first telescopic rod 6 and the second telescopic rod 7; when the second blood vessel 200 is subjected to an external force other than the first telescopic rod 6 and the second telescopic rod 7, the first telescopic rod 6 and the second telescopic rod 7 allow the second blood vessel 200 to swing up and down relative to the predetermined angle.

[0031] When installing this extracorporeal blood vessel stent, first clamp the third fixing ring 3 on the outer periphery of the second blood vessel 200, then respectively sleeve the first fixing ring 1 and the second fixing ring 2 on the first blood vessel 100 upstream and downstream of the anastomosis 300, and finally use the connecting rod assembly to rigidly connect the first fixing ring 1 and the second fixing ring 2 together, that is, complete the installation of the extracorporeal blood vessel stent on the outer peripheries of the first blood vessel 100 and the second blood vessel 200, and the installation of the extracorporeal blood vessel stent is convenient and fast.

[0032] As Figure 1 and Figure 2 shown, in some embodiments, both the first fixing ring 1 and the second fixing ring 2 are open rings with an opening at one end and circumferentially arranged. The third fixing ring 3 is made of stainless steel material, and the third fixing ring 3 is a C-shaped ring with an opening at one end and circumferentially arranged. The C-shaped ring has its own elasticity, and the C-shaped ring can clamp the second blood vessel 200 located inside the C-shaped ring through its own elastic deformation. In an alternative embodiment, the first fixing ring 1 and the second fixing ring 2 are not limited to the structural form of an integral open ring, and the first fixing ring 1 and the second fixing ring 2 can also adopt a combination form of a pair of semi-circular arc pieces and a pair of locking bolts, and use a pair of locking bolts to lock the two ends of a pair of semi-circular arc pieces, so that a pair of semi-circular arc pieces are sleeved on the outer periphery of the first blood vessel 100.

[0033] As Figure 1 and Figure 2As shown, in some embodiments, the link assembly includes a first rigid rod 4 and a second rigid rod 5 which are oppositely arranged. One end of the first rigid rod 4 is rigidly connected to the first fixing ring 1 and the other end is rigidly connected to the second fixing ring 2. One end of the second rigid rod 5 is rigidly connected to the first fixing ring 1 and the other end is rigidly connected to the second fixing ring 2. In an alternative embodiment, the link assembly may further include three or more rigid rods. The link assembly may also be replaced by a C-shaped cross-section tube with a C-shaped cross-section, as long as the link assembly can achieve the rigid connection between the first fixing ring 1 and the second fixing ring 2 and does not allow relative position movement between the first fixing ring 1 and the second fixing ring 2.

[0034] As Figure 1 and Figure 2 As shown, in some embodiments, the first fixing ring 1 and the second fixing ring 2 are both provided with clamping grooves, and both ends of the first rigid rod 4 and the second rigid rod 5 are provided with clamping blocks that can be embedded in the corresponding clamping grooves; the part of the clamping block embedded in the clamping groove has the same shape as the outer shape of the clamping groove to achieve their rigid connection. In an alternative embodiment, the positions of the clamping groove and the clamping block can be interchanged; the connection manner between the fixing ring and the rigid rod is not limited to the connection manner of the clamping block and the clamping groove engaging with each other. Any manner that can achieve detachable and rigid connection between the fixing ring and the rigid rod is within the scope of protection required by this application. This extracorporeal blood vessel stent composed of the first fixing ring 1, the second fixing ring 2, the third fixing ring 3, the first rigid rod 4, the second rigid rod 5, the first telescopic rod 6 and the second telescopic rod 7 has a simple overall structure. After installation, it can provide reliable external support for the first blood vessel 100 and the second blood vessel 200, and can prevent problems such as excessive stress in the second blood vessel 200.

[0035] As Figure 2 and Figure 3As shown, in some embodiments, the first telescopic rod 6 includes a first outer tube body 61, a first inner rod body 62, and a first elastic member 63. Among them, one end of the first outer tube body 61 is hinged to the first fixed ring 1, one end of the first inner rod body 62 extends into the first outer tube body 61 and is telescopically arranged along the axial direction of the first outer tube body 61, the other end of the first inner rod body 62 is hinged to the third fixed ring 3, and the first elastic member 63 is arranged in the first outer tube body 61 and elastically abuts against the first inner rod body 62 at one end. The second telescopic rod 7 includes a second outer tube body 71, a second inner rod body 72, and a second elastic member 73; one end of the second outer tube body 71 is hinged to the second fixed ring 2, one end of the second inner rod body 72 extends into the second outer tube body 71 and is telescopically arranged along the axial direction of the second outer tube body 71, the other end of the second inner rod body 72 is hinged to the third fixed ring 3, and the second elastic member 73 is arranged in the second outer tube body 71 and elastically abuts against the second inner rod body 72 at one end. Since both the first telescopic rod 6 and the second telescopic rod 7 are telescopic rod bodies with elasticity and axially telescopic, the second blood vessel 200 is kept at a predetermined angle with the first blood vessel 100 under the combined action of the first telescopic rod 6 and the second telescopic rod 7. When the fluid pressure in the second blood vessel 200 is relatively high, the second blood vessel 200 can swing relative to the predetermined angle, which can alleviate the excessive blood flow change of the second blood vessel 200 in the initial stage of the formation of the anastomosis part 300, and avoid lesions such as intimal thickening on the wall of the second blood vessel 200 due to excessive blood flow pressure.

[0036] As Figure 2 and Figure 3 shown, when the second blood vessel 200 and the first blood vessel 100 are kept at the predetermined angular position, the length of the first telescopic rod 6 is greater than the maximum length of the second telescopic rod 7 during the telescopic process, and when the second blood vessel 200 swings up and down relative to the predetermined angle, the length of the first telescopic rod 6 is always greater than the length of the second telescopic rod 7. When the second blood vessel 200 and the first blood vessel 100 are kept at the predetermined angular position, the supporting force of the first telescopic rod 6 on the second blood vessel 200 is less than the supporting force of the second telescopic rod 7 on the second blood vessel 200, and the resultant force of the supporting force of the first telescopic rod 6 on the second blood vessel 200 and the supporting force of the second telescopic rod 7 on the second blood vessel 200 is balanced with the gravity of the part of the second blood vessel 200 close to the anastomosis opening 300; so as to keep the second blood vessel 200 at a predetermined angle convenient for blood flow to smoothly flow from the upstream of the first blood vessel 100 through the anastomosis opening 300 into the second blood vessel 200.

[0037] During the arteriovenous (AV) anastomosis operation, the venous blood vessel is cut, an incision is made in the arterial blood vessel wall, and the open end of the venous blood vessel is sutured to the incision of the arterial blood vessel to form an arteriovenous fistula; the third fixing ring 3 of the above-mentioned blood vessel external stent is clamped and sleeved on the venous blood vessel near the anastomosis, then the first fixing ring 1 is sleeved on the outer periphery of the arterial blood vessel upstream of the anastomosis, the second fixing ring 2 is sleeved on the outer periphery of the arterial blood vessel downstream of the anastomosis, and finally the two ends of the first rigid rod 4 and the second rigid rod 5 are rigidly fixed to the first fixing ring 1 and the second fixing ring 2 respectively, thus completing the installation of the external blood vessel stent for the arteriovenous fistula. After installation, the blood vessel external stent can provide reliable external support for the arteriovenous fistula, preventing pathological changes such as intimal hyperplasia, blockage, and stenosis of the blood vessel wall of the venous blood vessel caused by excessive stress.

[0038] In summary, the blood vessel external stent provided by the embodiment of the present invention is composed of a first fixing ring 1, a second fixing ring 2, a third fixing ring 3, a first rigid rod 4, a second rigid rod 5, a first telescopic rod 6, and a second telescopic rod 7. The overall structure is simple and can provide reliable external support for the first blood vessel 100 and the second blood vessel 200. Moreover, since both the first telescopic rod 6 and the second telescopic rod 7 are elastic and axially telescopic telescopic rod bodies, the second blood vessel 200 is kept at a predetermined angle with the first blood vessel 100 under the combined action of the first telescopic rod 6 and the second telescopic rod 7. When the fluid pressure in the second blood vessel 200 is relatively high, the second blood vessel 200 can deflect relative to the predetermined angle, which can relieve the excessive blood flow change of the second blood vessel 200 in the initial stage of the formation of the anastomosis part 300, and avoid pathological changes such as intimal hyperplasia of the blood vessel wall of the second blood vessel 200 due to excessive blood flow pressure.

[0039] Obviously, the above embodiments are only examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An extravascular stent, characterized in that, Comprising: A fixed bracket, including a first fixing ring (1), a second fixing ring (2), and a connecting rod assembly rigidly connected between the first fixing ring (1) and the second fixing ring (2); wherein, the first fixing ring (1) is adapted to be sleeved on the outer periphery of a first blood vessel (100) upstream of an anastomosis (300), the second fixing ring (2) is adapted to be sleeved on the outer periphery of the first blood vessel (100) downstream of the anastomosis (300), and the anastomosis (300) is the position where a second blood vessel (200) is attached to the first blood vessel (100); A movable bracket, including a third fixing ring (3), a first telescopic rod (6), and a second telescopic rod (7); the third fixing ring (3) is adapted to be sleeved on the outer periphery of the second blood vessel (200); one end of the first telescopic rod (6) is connected to the first fixing ring (1), and the other end is connected to the third fixing ring (3); one end of the second telescopic rod (7) is connected to the second fixing ring (2), and the other end is connected to the third fixing ring (3); Both the first telescopic rod (6) and the second telescopic rod (7) are telescopic rod bodies with elasticity and capable of axial telescoping; the second blood vessel (200) is adapted to be maintained at a predetermined angle with the first blood vessel (100) under the combined action of the first telescopic rod (6) and the second telescopic rod (7); when the second blood vessel (200) is subjected to an external force other than the first telescopic rod (6) and the second telescopic rod (7), the first telescopic rod (6) and the second telescopic rod (7) allow the second blood vessel (200) to swing up and down relative to the predetermined angle.

2. The extracorporeal stent according to claim 1, characterized in that, Both the first fixing ring (1) and the second fixing ring (2) are open rings with an opening at one end and circumferentially arranged.

3. The extracorporeal stent according to claim 1, wherein, The third fixing ring (3) is a C-shaped ring with an opening at one end and circumferentially arranged. The C-shaped ring has its own elasticity and is adapted to clamp the second blood vessel (200) located within the C-shaped ring through its own elastic deformation.

4. The extravascular stent according to claim 3, characterized in that, The third fixing ring (3) is made of stainless steel material.

5. The extracorporeal stent according to claim 1, characterized in that, The connecting rod assembly includes a first rigid rod (4) and a second rigid rod (5) arranged oppositely. One end of the first rigid rod (4) is rigidly connected to the first fixing ring (1), and the other end is rigidly connected to the second fixing ring (2). One end of the second rigid rod (5) is rigidly connected to the first fixing ring (1), and the other end is rigidly connected to the second fixing ring (2).

6. The extracorporeal stent according to claim 5, wherein Both the first fixing ring (1) and the second fixing ring (2) are provided with card slots, and both ends of the first rigid rod (4) and the second rigid rod (5) are provided with blocks that can be embedded into the corresponding card slots; the part of the block embedded in the card slot has the same shape as the outer shape of the card slot to achieve rigid connection between the two.

7. The extravascular stent according to any one of claims 1-6, characterized in that, The first telescopic rod (6) includes a first outer tube body (61), a first inner rod body (62), and a first elastic member (63); one end of the first outer tube body (61) is hinged to the first fixing ring (1), one end of the first inner rod body (62) extends into the first outer tube body (61) and is telescopically arranged along the axial direction of the first outer tube body (61), the other end of the first inner rod body (62) is hinged to the third fixing ring (3), and the first elastic member (63) is arranged in the first outer tube body (61) and elastically abuts against the first inner rod body (62) at one end. The second telescopic rod (7) includes a second outer tube body (71), a second inner rod body (72), and a second elastic member (73); one end of the second outer tube body (71) is hinged to the second fixing ring (2), one end of the second inner rod body (72) extends into the second outer tube body (71) and is telescopically arranged along the axial direction of the second outer tube body (71), the other end of the second inner rod body (72) is hinged to the third fixing ring (3), and the second elastic member (73) is arranged in the second outer tube body (71) and elastically abuts against the second inner rod body (72) at one end.

8. The extravascular stent according to claim 7, wherein When the second blood vessel (200) and the first blood vessel (100) are maintained at a predetermined angular position, the resultant force of the supporting force of the first telescopic rod (6) on the second blood vessel (200) and the supporting force of the second telescopic rod (7) on the second blood vessel (200) is balanced with the gravity of the part of the second blood vessel (200) close to the anastomosis (300).

9. The extravascular stent according to claim 8, wherein, When the second blood vessel (200) and the first blood vessel (100) are maintained at a predetermined angular position, the supporting force of the first telescopic rod (6) on the second blood vessel (200) is less than the supporting force of the second telescopic rod (7) on the second blood vessel (200).

10. The extravascular stent according to claim 9, wherein The shortest length of the first telescopic rod (6) during the telescopic process is greater than the maximum length of the second telescopic rod (7) during the telescopic process.

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