Sleeve for supporting arteriovenous fistula blood vessel and supporting device

Abstract

The utility model discloses a cannula for supporting arteriovenous fistula blood vessels and a supporting device, the cannula is used for sleeving a vein anastomosis connection section, and the cannula is provided with a first end close to an artery anastomosis connection section and a second end far away from the artery anastomosis connection section; in the extending direction from the first end to the second end, the sleeve is bent towards one side, and the length of the sleeve is 10-15 mm. According to the cannula for supporting the arteriovenous fistula blood vessel, by designing the bending form of the cannula, the space angle of the vein anastomosis connecting section is optimized, so that the space angle of the vein anastomosis connecting section is limited within the range of 10-20 degrees; therefore, oscillation shear stress of blood on arteriovenous fistula blood vessels can be well reduced, negative effects of artery blood flow are avoided, and then the problem that the arteriovenous fistula blood vessels are narrow or blocked due to the fact that oscillation shear stress concentration areas exist in the arteriovenous fistula blood vessels is reliably solved.

Description

Technical Field

[0001] This application relates to the field of medical devices, and more specifically to a cannula for supporting arteriovenous fistula vessels, and also to a support device including the aforementioned cannula for supporting arteriovenous fistula vessels. Background Technology

[0002] To facilitate dialysis, an arteriovenous fistula (AGF) is typically created within the patient, forming a vascular access. The opening at the end of the venous anastomosis segment connects to the opening on the circumferential side of the arterial anastomosis segment, and the two openings are joined to form the AGF. The arterial and venous anastomosis segments together constitute the AGF vessel. Blood flows directly from the arterial anastomosis segment through the AGF to the venous anastomosis segment. However, due to the impact of blood flow on the venous anastomosis segment, the venous anastomosis segment struggles to adapt to the large blood flow impact, easily leading to remodeling and thickening of the venous anastomosis segment's vessel wall. This can cause stenosis or occlusion of the AGF vessel, affecting vessel maturation at the fistula site, thus reducing blood flow and impacting dialysis effectiveness.

[0003] The inventors, through analysis of existing clinical data, discovered that patients with higher fistula maturation rates and lower re-intervention rates typically exhibit vascular morphology with a certain angle between the venous and arterial segments. However, existing fistula creation methods struggle to shape the vessels into an angle conducive to fistula maturation. Therefore, there is an urgent need to develop an external support device at the arteriovenous fistula site to shape the vessel, minimizing the negative impact on blood flow at the arterial anastomosis segment and thus preventing stenosis, occlusion, or negative impacts on fistula maturation rates. Utility Model Content

[0004] In view of this, this application provides a cannula for supporting arteriovenous fistula vessels, and also provides a support device including the aforementioned cannula for supporting arteriovenous fistula vessels, which solves the problem of not being able to effectively reduce the negative impact caused by arterial blood flow, and the easy occurrence of arteriovenous fistula vessel stenosis, occlusion, or reduced fistula establishment maturity rate.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A cannula for supporting arteriovenous fistula vessels, the cannula being fitted onto a venous anastomosis segment, the cannula having a first end near the arterial anastomosis segment and a second end away from the arterial anastomosis segment;

[0007] Extending from the first end to the second end, the sleeve is bent to one side, and the length of the sleeve is 10mm-15mm.

[0008] Optionally, the cannula is bent to one side to form a spatial angle, the spatial angle of the cannula being 10°-20°, and the center lines of the arterial anastomosis segment and the venous anastomosis segment forming an anastomosis plane. The spatial angle of the cannula is the angle formed by the center line of the cannula relative to the anastomosis plane when the cannula is fitted onto the venous anastomosis segment.

[0009] Optionally, the cannula is curved in a section perpendicular to the centerline of the arterial anastomosis segment.

[0010] Optionally, the centerline of the sleeve is an arc, and the radius R of the arc is 12mm-18mm; and / or,

[0011] The centerline of the sleeve includes a first center point located at the first end and a second center point located at the second end; the straight-line distance L between the first center point and the second center point is 10mm-12mm.

[0012] Optionally, the cross-sectional dimensions of the sleeve gradually increase from the first end to the second end in the extending direction.

[0013] Optionally, the diameter D1 of the cross-section at the first end is 3mm-4mm; and / or,

[0014] The diameter D2 of the cross-section at the second end is 4mm-5.5mm.

[0015] Optionally, the sleeve is any one of a braided mesh sleeve, a film-coated support sleeve, a metal-cut sleeve, or a 3D-printed sleeve; and / or,

[0016] The sleeve is a biodegradable sleeve or a polymer sleeve.

[0017] A support device is also provided, including a connector and a cannula for supporting the arteriovenous fistula vessels, wherein the connector is used to be sleeved on the arterial anastomosis segment and the venous anastomosis segment, and the cannula is fixed to the connector.

[0018] Optionally, the connector forms an anastomosis angle at portions of the arterial anastomosis connection segment and the venous anastomosis connection segment, the anastomosis angle being 55°-75°.

[0019] Optionally, the coupling includes:

[0020] The first annular portion can be fitted onto the arterial anastomosis connection segment;

[0021] The second annular portion is connected to the first annular portion and can be fitted onto the venous anastomosis connection segment;

[0022] The sleeve is fixed to the second annular portion.

[0023] The cannula and support device for supporting arteriovenous fistula vessels provided in this application optimize the spatial angle of the venous anastomosis segment by designing the bending shape of the cannula. Furthermore, the appropriate length of the cannula ensures support for the fixed venous anastomosis segment. Combined with the bending shape of the cannula, for example, the spatial angle of the venous anastomosis segment is limited to the range of 10°-20°. As such, a better fistula establishment angle and good hemodynamics can be obtained, which is conducive to the maturation of the fistula. It also effectively reduces the oscillatory shear stress of blood on the arteriovenous fistula vessel, avoiding the negative impact of arterial blood flow. This reliably prevents the arteriovenous fistula vessel from narrowing or becoming occluded due to the presence of oscillatory shear stress concentration areas. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of an arteriovenous fistula.

[0026] Figure 2 This diagram represents the anastomosis plane, spatial angle, and anastomosis angle of an arteriovenous fistula.

[0027] Figure 3 This is a schematic diagram of the sleeve structure of this application.

[0028] Figure 4 This is a schematic diagram of the structure of the connector of this application disposed in an arteriovenous fistula vessel.

[0029] Figure 5 This is a schematic diagram of the support device of this application disposed in an arteriovenous fistula vessel.

[0030] Figure 6 for Figure 5 The main view.

[0031] Figure 7 for Figure 5 Side view.

[0032] Figure 8 This is a graph of the oscillating shear stress exponential curve.

[0033] Figures 1-8 middle:

[0034] 1. Connecting element; 2. Cannula; 3. Arterial anastomosis connection segment; 4. Venous anastomosis connection segment; 5. Anastomosis point;

[0035] 11. First annular portion; 12. Second annular portion;

[0036] 21. First end; 22. Second end;

[0037] 31. First center line; 32. First point; 33. Second point;

[0038] 41. Second center line; 42. Third point; 43. Fourth point. Detailed Implementation

[0039] This application provides a cannula for supporting arteriovenous fistula vessels, and also provides a support device including the aforementioned cannula for supporting arteriovenous fistula vessels.

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] For ease of illustration and understanding, the following embodiments are described within the scope of an exemplary cannula for arteriovenous fistulas prepared in a patient to facilitate hemodialysis. However, the embodiments described herein are not limited to the specific scenarios described, and may be adapted to different clinical applications without departing from the overall scope of this application; for example, in the vascular system or other organs, structures incorporating the concepts described herein may be used to prevent and / or treat intimal hyperplasia or to reconstruct other artificial anatomical junctions, including end-to-side opening, end-to-end opening, or side-to-side opening anastomoses. This embodiment illustrates a vascular reconstruction pathway from a venous end-to-side opening to an arterial side-to-side opening.

[0042] Please see the appendix Figure 1-7 This application provides a cannula 2 for supporting arteriovenous fistula vessels, which is used to fit over the venous anastomosis segment 4 at the arteriovenous fistula. The cannula 2 has a first end 21 close to the arterial anastomosis segment 3 and a second end 22 away from the arterial anastomosis segment 3. Extending from the first end 21 to the second end 22, the cannula 2 is bent to one side, and the length of the cannula 2 is 10mm-15mm, for example, any one of 10mm, 11mm, 12mm, 13mm, 14mm, and 15mm, or an intermediate value of the aforementioned values. The appropriate length allows the fixed venous anastomosis segment 4 to be supported, as well as a better fistula creation angle and good hemodynamics.

[0043] The sleeve 2 is bent to one side to form a spatial angle or non-planar angle, and the spatial angle of the sleeve 2 is 10°-20°; for example, the spatial angle of the sleeve 2 can be any one of 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20° or an intermediate value of the aforementioned values; preferably, the spatial angle of the sleeve 2 is 17°.

[0044] It should be noted that the "cannula 2 supporting the arteriovenous fistula vessel" will be referred to as "cannula 2" in the following text. The opening at the end of the venous anastomosis segment 4 connects to the opening on the circumferential side of the arterial anastomosis segment 3. The two openings are anastomosed to form an arteriovenous fistula, and blood flows directly from the arterial anastomosis segment 3 through the arteriovenous fistula to the venous anastomosis segment 4. The arterial anastomosis segment 3 and the venous anastomosis segment 4 are anastomosed to form the arteriovenous fistula vessel.

[0045] Please see the appendix Figure 1-2 It should be further explained that the arterial anastomosis segment 3 has a first central line 31, and the venous anastomosis segment 4 has a second central line 41. The intersection of the first central line 31 and the second central line 41 is the anastomosis point 5. Along the first central line 31, extending 1 cm from the anastomosis point 5 to both ends respectively, the first point 32 and the second point 33 are formed. Along the second central line 41, extending 1 cm from the anastomosis point 5 in a direction away from the arteriovenous fistula, the third point 42 is formed. The anastomosis plane is defined by a position 1 cm away from the anastomosis point 5, that is, the plane containing the first point 32, the second point 33, and the third point 42 forms the anastomosis plane.

[0046] The spatial angle of cannula 2 refers to the angle between the centerline of cannula 2 and the anastomosis plane when cannula 2 is fitted onto the venous anastomosis segment 4; the spatial angle of venous anastomosis segment 4 refers to the angle between the second centerline 41 of venous anastomosis segment 4 and the anastomosis plane.

[0047] The cannula 2 is spaced a certain distance from the arteriovenous fistula anastomosis site. The centerline of the cannula 2 includes an extension segment extending towards the anastomosis point 5, which coincides with the second centerline 41 of the venous anastomosis connection segment 4. Furthermore, the shape of the venous anastomosis connection segment 4 is constrained by the shape of the cannula 2 fitted around its periphery. Therefore, the second centerline 41 overlaps with the centerline of the cannula 2, and thus the spatial angle of the venous anastomosis connection segment 4 is consistent with the spatial angle of the cannula 2.

[0048] Please see the appendix Figure 2Specifically, along the second centerline 41 (that is, along the centerline of the cannula 2), a fourth point 43 is formed by extending 3 cm away from the anastomosis point 5 in a direction away from the arteriovenous fistula. The position of the fourth point 43 is defined considering the extreme position of the venous anastomosis segment 4 near the skin, that is, the distal end of the cannula 2 or its vicinity. The fourth point 43 is used as a reference point for spatial angle. The line segment from the anastomosis point 5 to the fourth point 43 is the first line segment. The angle between the first line segment and the anastomosis plane is defined as the spatial angle of the venous anastomosis segment 4, that is, the spatial angle of the cannula 2.

[0049] The cannula 2 can limit the diameter of the venous anastomosis segment 4 to constrain the shape of the venous anastomosis segment 4. It has the function of guiding the venous anastomosis segment 4, so that the venous anastomosis segment 4 maintains a certain spatial angle, thereby reducing the oscillatory shear stress generated by blood flow, which is conducive to the maturation of arteriovenous fistula.

[0050] This application limits the spatial angle of the cannula 2 to the range of 10°-20°, thereby limiting the spatial angle of the venous anastomosis connection segment 4 to the range of 10°-20° through the cannula 2; as above, it can effectively reduce the oscillatory shear stress of blood on the arteriovenous fistula vessel, avoid the negative impact of arterial blood flow, and thus reliably avoid the problem of stenosis or occlusion of the arteriovenous fistula vessel due to the presence of an oscillatory shear stress concentration area.

[0051] Please see the appendix Figure 7 In some embodiments of this application, in a cross section perpendicular to the first centerline 31 of the arterial anastomosis segment 3, the cannula 2 is curved in the direction of extension from the first end 21 to the second end 22.

[0052] As mentioned above, by limiting the shape of the cannula 2, the spatial angle formed by the cannula 2 can be guaranteed; and since the cannula 2 is curved, there is no stress concentration area on its outer periphery, which can reduce the compression and damage to the vessel wall of the venous anastomosis segment 4; at the same time, it can improve blood flow, reduce blood stagnation, and help reduce the oscillatory shear stress of blood on the venous anastomosis segment 4, avoid narrowing or blockage of the venous anastomosis segment 4, and thus avoid thrombosis, so as to maintain the smooth flow of blood.

[0053] Please see the appendix Figure 3 In some embodiments of this application, the centerline of the sleeve 2 is an arc, and the radius R of the arc is 12mm-18mm; for example, R can be any one of 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm or an intermediate value of the foregoing; preferably, R is 15mm.

[0054] Please see the appendix Figure 3In some embodiments, the centerline of the sleeve 2 includes a first center point located at the first end 21 and a second center point located at the second end 22. The straight-line distance L from the first center point to the second center point is 10mm-12mm; for example, L can be any one of 10mm, 10.5mm, 10.7mm, 11mm, 11.5mm, 11.7mm, 12mm or an intermediate value of the foregoing; preferably, L is 11.7mm.

[0055] By limiting the above parameters, the bending shape of sleeve 2 can be precisely defined, thereby ensuring that the spatial angle of sleeve 2 is within the optimal range of 10°-20°. The selection of the above parameters of sleeve 2 can be adjusted according to actual needs, and will not be elaborated on in detail here.

[0056] It should be noted that the arterial anastomosis segment of the arteriovenous fistula is fitted with a connector 1, which can be various connectors or devices used to fix the cannula 2 in the correct position. Of course, the cannula 2 of this application can also be used alone and directly fixed to the venous anastomosis segment 4 by adhesive or heat shrinking.

[0057] Please see the appendix Figure 4-7 Based on the aforementioned cannula 2 supporting the arteriovenous fistula vessel, this application embodiment also provides a support device, which includes a connector 1 and the aforementioned cannula 2 supporting the arteriovenous fistula vessel. The connector 1 is sleeved on the arterial anastomosis connection segment 3 and the venous anastomosis connection segment 4, and the cannula 2 is sleeved on the venous anastomosis connection segment 4 and fixed to the connector 1.

[0058] The connector 1 supports the arteriovenous fistula vessel, has high rigidity, can resist high blood flow impact and contract to form the anastomosis of the arteriovenous fistula.

[0059] Since the support device has the aforementioned cannula 2 that supports the arteriovenous fistula, the beneficial effects of the support device brought by the aforementioned cannula 2 can be found in the above description and will not be repeated here.

[0060] Please see the appendix Figure 5-6 In some embodiments of this application, the connector 1 forms an anastomosis angle at a portion of the arterial anastomosis connection segment 3 and the venous anastomosis connection segment 4, wherein the anastomosis angle is 55°-75°; for example, the anastomosis angle can be any one of 55°, 60°, 65°, 70°, and 75°; preferably, the anastomosis angle is 58°.

[0061] It should be noted that the anastomosis angle of the connector 1 refers to the angle between the center line of the first annular portion 11 of the connector 1 fitted onto the arterial anastomosis segment 3 and the center line of the second annular portion 12 fitted onto the venous anastomosis segment 4 when the support device is fitted onto the arteriovenous fistula vessel. The anastomosis angle between the arterial anastomosis segment 3 and the venous anastomosis segment 4 refers to the angle between the first center line 31 of the arterial anastomosis segment 3 and the second center line 41 of the venous anastomosis segment 4.

[0062] Furthermore, the shape of the arteriovenous fistula is constrained by the support device, so the center line 31 overlaps with the center line of the first annular portion 11, and the center line of the venous anastomosis connection segment 4 sleeved on the connector overlaps with the center line of the second annular portion 12. Therefore, the "anastomosis angle between the arterial anastomosis connection segment 3 and the venous anastomosis connection segment 4" is the same as the "anastomosis angle formed by the first annular portion 11 and the second annular portion 12 of the connector 1".

[0063] Please see the appendix Figure 2 Specifically, the line segment from the mating point 5 to the first point 32 is the second line segment, and the line segment from the mating point 5 to the third point 42 is the third line segment. The angle between the second and third line segments is the mating angle between the connector 1 and the sleeve 2.

[0064] By controlling the anastomosis angle between the connector 1 and the cannula 2, the anastomosis angle between the venous anastomosis segment 4 and the arterial anastomosis segment 3 is optimized, limiting the anastomosis angle to the range of 55°-75°. As such, the oscillatory shear stress of blood on the arteriovenous fistula can be further reduced, avoiding the negative impact of arterial blood flow, and thus reliably avoiding the problem of stenosis or occlusion of the arteriovenous fistula due to the presence of an oscillatory shear stress concentration area.

[0065] The combined action of connector 1 and cannula 2 achieves joint constraint on the spatial angle of the venous anastomosis connection segment 4 and the anastomosis angle between the venous anastomosis connection segment 4 and the arterial anastomosis connection segment 3, thereby minimizing the oscillatory shear stress of blood on the arteriovenous fistula vessels. Please refer to the appendix. Figure 8 It is a graph showing the oscillating shear stress index under varying coincidence angles and spatial angles in this application; from the attached... Figure 8 It can be seen that when the anastomosis angle of the venous anastomosis segment 4 is between 10° and 20°, and the anastomosis angle between the venous anastomosis segment 4 and the arterial anastomosis segment 3 is between 55° and 75°, the oscillating shear stress of blood on the arteriovenous fistula can be minimized.

[0066] Please see the appendix Figure 3 , 5 -7. In some embodiments of this application, the cross-sectional size of the sleeve 2 gradually increases from the first end 21 to the second end 22.

[0067] As described above, the cannula 2 constrains the venous anastomosis segment 4 to exhibit a shape in which the cross-sectional size gradually increases in the direction away from the arteriovenous fistula, i.e., it presents a funnel-shaped or diffused shape. At this time, when the blood from the arterial anastomosis segment 3 passes through the arteriovenous fistula to the venous anastomosis segment 4, the blood enters from the port with a smaller cross-sectional size and flows out from the port with a larger cross-sectional size. This helps to reduce the oscillatory shear stress of the blood on the venous anastomosis segment 4, prevent vascular damage, and at the same time help to prevent blood backflow, ensuring that the blood flows in a single direction within the venous anastomosis segment 4.

[0068] Please see the appendix Figure 3 In some embodiments of this application, the diameter D1 of the cross-section of the first end 21 is 3mm-4mm; for example, D1 can be any one of 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm or an intermediate value of the foregoing; preferably, D1 is 3.4mm.

[0069] Please see the appendix Figure 3 In some embodiments, the diameter D2 of the cross-section of the second end 22 is 4mm-5.5mm; for example, D1 can be any one of 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm or an intermediate value of the foregoing; preferably, D1 is 4.7mm.

[0070] As mentioned above, limiting the dimensions of D1 and D2 within the aforementioned range can effectively define the funnel-shaped or diffused shape of the cannula 2. This, in turn, constrains the shape of the venous anastomosis connection segment 4 through the cannula 2, ensuring that the blood has a sufficient flow velocity within the venous anastomosis connection segment 4 and maintaining the stability of blood flow.

[0071] Please see the appendix Figure 6 In some embodiments of this application, the connector 1 includes a first annular portion 11 and a second annular portion 12. The first annular portion 11 can be fitted onto the arterial anastomosis segment 3. The second annular portion 12 is connected to the first annular portion 11 and can be fitted onto the venous anastomosis segment 4. The cannula 2 is fixed to the second annular portion 12.

[0072] It should be noted that the coupling 1 can be various connectors or devices used to fix the sleeve 2 in the correct position. The sleeve 2 can be fitted inside or outside the second annular portion 12. The sleeve 2 can be bonded to the second annular portion 12 or welded to the second annular portion 12.

[0073] As shown above, the fixed setting of sleeve 2 is achieved. The setting method can be selected according to the actual scenario, making it highly flexible and applicable.

[0074] In some embodiments of this application, the sleeve 2 is any one of a braided mesh sleeve, a film-coated scaffold sleeve, a metal-cut sleeve, or a 3D-printed sleeve. Further, the sleeve 2 is a biodegradable sleeve or a polymer sleeve.

[0075] As shown above, the types of sleeve 2 have been enriched, and the setting type can be selected according to the actual scenario, making it highly flexible and applicable.

[0076] Those skilled in the art will recognize that these components and devices can be connected, arranged, and configured in any manner. Words such as “including,” “comprising,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The words “or” and “and” as used herein refer to the words “and / or,” and are used interchangeably with them unless the context explicitly indicates otherwise. The word “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0077] It should also be noted that in the apparatus of this application, the components can be disassembled and / or reassembled. These disassemblies and / or reassemblies should be considered as equivalent solutions of this application.

[0078] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be applied within the widest scope consistent with the principles and novel features disclosed herein.

[0079] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

[0080] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cannula for supporting a blood vessel of an arteriovenous fistula, characterized in that The sleeve (2) is used for sleeving the venous anastomosis connecting segment (4), the sleeve (2) has a first end (21) close to the arterial anastomosis connecting segment (3), a second end (22) away from the arterial anastomosis connecting segment (3); The sleeve is curved towards one side in the extension direction from the first end (21) to the second end (22), and the length of the sleeve is 10-15 mm; The sleeve (2) is curved towards one side to form a spatial angle, the spatial angle of the sleeve (2) is 10-20°, the arterial anastomosis connecting segment (3) and the center line of the venous anastomosis connecting segment (4) form an anastomosis plane, and the spatial angle of the sleeve (2) is the angle formed by the center line of the sleeve (2) relative to the anastomosis plane when the sleeve (2) is sleeved on the venous anastomosis connecting segment (4).

2. The cannula supporting an arteriovenous fistula blood vessel of claim 1, wherein, The sleeve is curved in a cross section perpendicular to the center line of the arterial anastomosis connecting segment (3).

3. The cannula supporting an arteriovenous fistula blood vessel of claim 2, wherein, The center line of the sleeve (2) is a circular arc line, and the radius R of the circular arc line is 12-18 mm; and / or, The center line of the sleeve (2) includes a first center point at the first end (21) and a second center point at the second end (22); the straight line distance L from the first center point to the second center point is 10-12 mm.

4. The cannula supporting an arteriovenous fistula blood vessel of claim 1, wherein, The cross-sectional size of the sleeve (2) gradually increases in the extension direction from the first end (21) to the second end (22).

5. The sleeve for supporting the blood vessel of arteriovenous fistula according to claim 4, wherein The diameter D1 of the cross section of the first end (21) is 3-4 mm; and / or The diameter D2 of the cross section of the second end (22) is 4-5.5 mm.

6. The sleeve for supporting the blood vessel of arteriovenous fistula according to any one of claims 1-5, wherein The sleeve (2) is any one of a woven mesh sleeve, a covered stent sleeve, a metal cutting sleeve, and a 3D printed sleeve; and / or The sleeve (2) is a biodegradable sleeve or a polymer sleeve.

7. A support device characterized by, The sleeve (2) for supporting the blood vessel of arteriovenous fistula according to any one of claims 1-6, and a coupling member (1) for sleeving the arterial anastomosis connecting segment (3) and the venous anastomosis connecting segment (4), the sleeve (2) being fixed to the coupling member.

8. The support device of claim 7, wherein, The coupling member (1) forms an anastomosis angle at the part of the arterial anastomosis connecting segment (3) and the venous anastomosis connecting segment (4), and the anastomosis angle is 55-75°.

9. The support apparatus of claim 7, wherein, The coupling member (1) comprises: A first annular part (11) capable of sleeving the arterial anastomosis connecting segment (3); A second annular part (12) connected to the first annular part (11) and capable of sleeving the venous anastomosis connecting segment (4); The sleeve (2) is fixed to the second annular part (12).

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