An arteriovenous fistula vascular lining stent and methods of use thereof

Abstract

The application discloses an arteriovenous fistula blood vessel lining support and a use method thereof, and the arteriovenous fistula blood vessel lining support has a three-way pipe structure; the axes of two passages in the three-way pipe structure are on a straight line to form a straight pipe, and the axis of the other passage has a variable included angle with the straight line formed by the axes of the first two passages to form a bifurcated pipe; the straight pipe and the bifurcated pipe jointly form a three-way shape of the support with an inner cavity and have optional additional structures near each port; the straight pipe is used for being implanted into an arterial blood vessel; and the bifurcated pipe is used for sleeving a venous blood vessel which needs to be connected. After the arteriovenous fistula blood vessel lining support is embedded, the occurrence of turbulent flow is effectively reduced, blood composition deposition is reduced, the probability of vascular hyperplasia and vascular stenosis is reduced, the arteriovenous fistula maturation time is shortened, and the use time of the fistula is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of medical devices, specifically relating to an arteriovenous fistula lining stent and its usage method. Background Technology

[0002] As part of the urinary system, the kidneys are among the most important organs in the human body. They are responsible for filtering impurities from the blood, maintaining fluid and electrolyte balance, and producing urine which is excreted through the ureters and bladder. The kidneys also have endocrine functions. Normal individuals have two kidneys, located on either side of the lower back, behind the peritoneum. Chronic kidney disease (CKD) refers to various structural and functional impairments of the kidneys. Clinically, CKD is classified into stages 1-5 based on the glomerular filtration rate (GFR), corresponding to GFRs of ≥90, 60-89, 30-59, 15-29, and <15 mL / min / 1.73 m³, respectively. Stage 5 is also known as end-stage renal disease (ESRD), commonly referred to as uremia.

[0003] ESRD patients have suffered irreversible kidney damage and must undergo renal replacement therapy, including hemodialysis, peritoneal dialysis, and kidney transplantation. Due to the limited number of kidney donors and the high cost of treatment, only a very small number of patients can undergo kidney transplantation, and the vast majority of patients must undergo lifelong dialysis. In 2013, approximately 2.52 million patients worldwide received dialysis treatment; by 2020, this number had reached approximately 3.8 million. In 2013, China had approximately 2 million ESRD patients, with about 330,000 receiving dialysis treatment. By 2020, the number of patients had reached 5.35 million, but only about 830,000 were receiving dialysis treatment, representing only about 16%.

[0004] Besides market factors such as price, the poor treatment experience associated with dialysis is also a significant reason for the low rate of hemodialysis treatment in China. In addition to the dialysis itself, the preparation process before dialysis is lengthy and relatively complex. To perform hemodialysis, a vascular access capable of supporting a large blood flow is usually established beforehand, and arteriovenous fistula (AVF) is the preferred clinical option. AVF uses vascular surgery techniques to artificially create a short circuit between an artery and a vein. The clinically recommended first-line surgery is autogenous arteriovenous fistula (AVF), which directly anastomoses the radial artery and cephalic vein in the distal forearm; it is also known as a "standard fistula" or "first-level vascular access." This surgery is widely used, but there are also cases of surgical failure and complications, including ① progressive stenosis and thrombosis of the venous outflow tract due to intimal hyperplasia and thrombosis, eventually leading to occlusion; ② infection; ③ aneurysms and pseudoaneurysms in the graft vessels, etc.

[0005] Chinese invention patent application CN115400278A discloses an external vascular stent for arteriovenous fistulas, comprising an arterial basal segment and a venous basal segment, which are respectively fitted over the artery and vein, including the aorta and vein, and fixed in place. This facilitates prolonged and proper encapsulation and tight compression at the arterial and venous connection, aiming to improve the fistula maturation rate and increase venous blood flow, thus benefiting dialysis. However, this stent differs fundamentally from the intravascular liner stent of this invention in both structure and usage. Chinese invention patent application CN114072185A discloses an implantable vascular access device that can be permanently implanted in patients with pre-existing arteriovenous fistulas to create a vascular connection between the artificial arteriovenous fistula and the dialysis system. Unlike the intravascular liner stent of this invention, this vascular access device is suitable for patients who have already formed arteriovenous fistulas, and its purpose, method, and content are fundamentally different from the arteriovenous fistula creation device provided by this invention.

[0006] To improve the overall success rate of AVF surgery and reduce complications, this invention provides an arteriovenous fistula lining stent solution. By using the stent proposed in this solution, AVF surgery can be completed more quickly and easily, and the occurrence of complications can be reduced. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to provide an arteriovenous fistula vascular liner stent, which is implanted into a blood vessel during arteriovenous fistula surgery and remains in the body, helping to complete arteriovenous fistula surgery more quickly, easily, and safely, improving the success rate of the surgery and reducing complications; another purpose of this invention is to provide a method for using the arteriovenous fistula vascular liner stent.

[0008] Technical Solution: The present invention provides an arteriovenous fistula vascular liner stent, which has a three-way tube structure. The three-way tube structure provides three branches, which are respectively connected to an artery and a vein. The outer diameter of the stent matches the diameter of the blood vessel lumen. In the three-way tube structure, the axes of two passages are aligned to form a straight tube, and the axis of the other passage has a variable angle with the straight line formed by the axes of the first two passages to form a bifurcated tube. The straight tube and the bifurcated tube together form the three-way shape of the hollow stent, and there are optional additional structures near each port. The straight tube is used for implantation into the arterial blood vessel; the bifurcated tube is used to fit the vein to be connected.

[0009] As a further improvement to the above solution, the arteriovenous fistula vascular liner stent meets one or more of the following conditions:

[0010] The straight tube length of the arteriovenous fistula lining stent is H1, the length of segment H2 is 0.1-0.9 times that of H1, and the outer diameters D1 and D2 of the straight tube are 0.01-0.2 times the length of H1.

[0011] D1 and D2 can be the same or different. If D1 and D2 are different, the straight tube section forms a cone shape with a smooth and gradual change in outer diameter.

[0012] The bifurcation tube is a section of arc tube with a radius of curvature R1, where R1 is 0.02-0.4 times H1, and the outer diameter D3 of the bifurcation tube is 0.01-0.2 times H1.

[0013] The lower part of the contact end between the branch pipe and the straight pipe is tangent to the straight pipe, and the upper part of the contact end is provided with a fillet with a radius of R2 between it and the straight pipe. The size of R2 is 0.01-0.2 times that of H1.

[0014] The axis perpendicular to the end face at the end of the bifurcated pipe forms an angle θ with the axis of the straight pipe. The angle θ ranges from 0 to π / 2 radians, with a preferred range of π / 6 to π / 3 radians. The end of the arc pipe is also connected to a straight pipe with an outer diameter of D3 and a length of H4. The length of H4 is 0 to 0.9 times that of H1.

[0015] As a further improvement to the above scheme, a number of grooves or protrusions are provided near each end face to facilitate the fixation of blood vessels. The distance H3 from the specific end face is 0.01-0.9 times that of H1. The number of grooves or protrusions is 1-5, preferably 1-3. The depth of the grooves or the height of the protrusions is 1 / 4-1 / 2 times the wall thickness.

[0016] As a further improvement to the above scheme, the wall thickness of the arteriovenous fistula lining stent is 0.05-3mm, preferably 0.1-1mm;

[0017] As a further improvement to the above solution, the arteriovenous fistula lining stent is completely closed or has a certain degree of hollow structure. The specific hollow structure can be a round hole or any other arbitrary shape. It still has sufficient support under the hollow structure. When the hollow structure is formed, the proportion of the blank surface area of ​​the stent after it is unfolded to the total surface area of ​​the stent is 10-90%.

[0018] As a further improvement to the above solution, the material of the arteriovenous fistula vascular liner stent is a biomedical material that has been approved for implantation into blood vessels; the material of the arteriovenous fistula vascular liner stent is selected from any of the following materials: stainless steel, cobalt-chromium alloy, nickel-titanium alloy, platinum-chromium alloy, magnesium alloy, pure iron, silicone rubber, polyethylene, polytetrafluoroethylene, polyethylene terephthalate, polyacrylate, polyamide, polyether block polyamide, polyurethane, polycaprolactone, polylactic acid and its copolymers.

[0019] As a further improvement to the above solution, the arteriovenous fistula lining stent can be either a drug-free stent made entirely of material or a drug-loaded stent.

[0020] As a further improvement to the above solution, the arteriovenous fistula vascular liner stent can be prepared by die casting, additive manufacturing or laser cutting methods.

[0021] On the other hand, the present invention provides a method of using the above-mentioned arteriovenous fistula vascular liner stent, wherein the arteriovenous fistula vascular liner stent is used in the process of arteriovenous fistula creation to assist in better formation of arteriovenous fistula and improve the success rate of fistula creation; the straight tube structure of the arteriovenous fistula vascular liner stent is implanted into the arterial blood vessel, and the vein to be connected is fitted on the bifurcation tube to form a short circuit connection between the arteriovenous blood vessels to form an arteriovenous fistula.

[0022] As a further improvement to the above scheme, after implantation into the blood vessel, the grooves or protrusions on the surface of the stent can be used to tie and fix it with surgical sutures; or an adhesive that can be used inside the blood vessel can be used for bonding and fixation.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0024] Currently, the clinical approach to autologous arteriovenous fistula surgery involves end-to-end / side anastomosis of arteriovenous vessels, followed by a 1-2 month maturation period. During the maturation period, vessel wall hyperplasia is more likely to occur at the fistula site, leading to fistula failure. When this type of arteriovenous fistula lining stent device is embedded during the fistula surgery, it can effectively reduce hyperplasia and continue to resist this hyperplasia after the fistula matures, thereby extending the service life of the fistula.

[0025] After the arteriovenous fistula surgery, the dialysis blood flow rate needs to reach 200-300 mL / min. However, due to the complex shape of the surgical anastomosis, turbulence is easily generated, which reduces the blood flow rate and fails to meet the requirements. After the arteriovenous fistula is linerged with an embedded stent, the tangential connection between the tubes and the smooth rounded corners at the connection point reduce the occurrence of turbulence, thereby reducing the deposition of blood components, lowering the probability of intravascular proliferation and vascular stenosis, shortening the maturation time of the arteriovenous fistula, and prolonging the service life of the fistula. Attached Figure Description

[0026] Figure 1 The basic structural morphology of the arteriovenous fistula lining stent;

[0027] Figure 2 Available sizes of stent linings for arteriovenous fistula vessels;

[0028] Figure 3 For arteriovenous fistula lining stents when H4=0 and H4>0;

[0029] Figure 4 An arteriovenous fistula liner stent with H4=0 and a perforated structure;

[0030] Figure 5 This is a polyacrylate arteriovenous fistula lining stent prepared by photopolymerization 3D printing. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, this embodiment of the invention provides an arteriovenous fistula lining stent with a three-way tube-like shape, providing three branches to connect to the artery and vein respectively. The outer diameter of the stent matches the diameter of the vessel lumen. The axes of two of the three-way tube-like passages are aligned to form a straight tube 1, and the axis of the other passage has a variable angle with the straight line formed by the axes of the first two passages to form a bifurcated tube 2. The straight tube and the bifurcated tube together form the three-way shape of the hollow stent, and there are optional additional structures 3 near each port.

[0033] like Figure 2-3As shown, the straight tube length of the arteriovenous fistula lining stent is H1, which is 10-200 mm, preferably 20-70 mm. The length of segment H2 is 0.1-0.9 times that of H1. The outer diameters D1 and D2 of the straight tube portion range from 0.01-0.2 times the length of H1. D1 and D2 can be the same or different. If D1 and D2 are different, the straight tube portion forms a cone shape with a smoothly gradually changing outer diameter. The bifurcation tube is an arc tube with a radius of curvature R1, where R1 is 0.02-0.02 times the length of H1. The outer diameter D3 of the bifurcation pipe is 0.01-0.2 times that of H1. The lower part of the contact end with the straight pipe is tangent to the straight pipe, and the upper part of the contact end is provided with a rounded corner with a radius of R2 between it and the straight pipe. The size of R2 is 0.01-0.2 times that of H1. The axis of the end of the bifurcation pipe perpendicular to the end face forms an angle θ with the axis of the straight pipe. The angle θ ranges from 0 to π / 2 radians, preferably from π / 6 to π / 3 radians. The tail end of the arc pipe is also connected to a straight pipe with an outer diameter of D3 and a length of H4. The length of H4 is 0 to 0.9 times that of H1.

[0034] In this embodiment of the invention, the arteriovenous fistula lining stent has a number of grooves or protrusions near each end face to facilitate fixation of the blood vessel. The distance H3 from the specific end face of the groove or protrusion is 0.01-0.9 times H1. The number of grooves or protrusions is 1-5, preferably 1-3. The depth of the groove or the height of the protrusion is 1 / 4-1 / 2 times the wall thickness.

[0035] In this embodiment of the invention, the wall thickness of the arteriovenous fistula lining stent is 0.05-3 mm, and the preferred wall thickness is 0.1-1 mm.

[0036] This invention provides an arteriovenous fistula lining stent that is either entirely closed or has a certain degree of perforation. The perforation can be a circular hole or any other arbitrary shape; for example... Figure 4 As shown, the hollow structure still has sufficient support. When the hollow structure is formed, the blank surface area of ​​the bracket after it is unfolded accounts for 10-90% of the total surface area of ​​the bracket.

[0037] In this embodiment of the invention, the material constituting the arteriovenous fistula vascular liner stent is a biomedical material that has been approved for implantation in blood vessels, including but not limited to metallic materials such as stainless steel, cobalt-chromium alloy, nickel-titanium alloy, platinum-chromium alloy, magnesium alloy, pure iron, etc., and organic polymer materials such as silicone rubber, polyethylene, polytetrafluoroethylene, polyethylene terephthalate, polyacrylate, polyamide, polyether block polyamide, polyurethane, polycaprolactone, polylactic acid and its copolymers, etc.

[0038] In this embodiment of the invention, the arteriovenous fistula lining stent can be either a drug-free stent made purely of material or a drug-loaded stent. When present as a drug-loaded stent, the drug can be loaded inside the stent's constituent materials or can exist on the surface of the stent as a coating; available drugs include, but are not limited to, heparin, paclitaxel and its derivatives, rapamycin and its derivatives, etc.

[0039] Among them, arteriovenous fistula vascular liner stents can be prepared by methods such as molding, additive manufacturing (3D printing), and laser cutting, with molding and 3D printing being the preferred methods.

[0040] When used, the stent is implanted into the blood vessel that needs to be connected to the fistula and anastomosed with the blood vessel. On the one hand, it forms a blood flow channel, and on the other hand, it also supports the blood vessel.

[0041] This invention provides a method for using an arteriovenous fistula vascular liner stent, wherein the straight tube structure is often implanted into an arterial vessel, and the vein to be connected is fitted onto the bifurcation tube, forming a short-circuit connection between the arteriovenous vessels to constitute an arteriovenous fistula.

[0042] After implantation into a blood vessel, the stent can be secured using surgical sutures by utilizing the grooves or protrusions on its surface; or it can be secured using an adhesive suitable for use within the blood vessel.

[0043] The following detailed description uses specific embodiments.

[0044] Example 1: As Figure 5 As shown, an arteriovenous fistula liner stent was prepared using acrylate as raw material and photopolymerization 3D printing method. The stent has H1 = 60 mm, H2 = 30 mm, H4 = 0 mm, no additional structures such as grooves or protrusions are provided near the end face, R1 = 7 mm, R2 = 1.5 mm, D1 = D2 = D3 = 2.5 mm, wall thickness 0.2 mm, and θ = π / 3 radians.

[0045] During the fistula surgery, a small incision is made on one side of the artery, and the straight tube of the arteriovenous fistula lining stent is embedded and fixed inside. Then, the venous sleeve is placed over the bifurcation tube and attached to the artery. It is then fixed with vascular adhesive to form a blood flow path. After the wound is sutured and healed, an arteriovenous fistula is formed. The 2mm inner diameter of the stent provides sufficient blood flow path and can be used for hemodialysis.

[0046] Example 2: Similar to Example 1, but using polylactic acid as the raw material and employing hot melt 3D printing, a support of the same size can be obtained.

[0047] Example 3: Similar to Example 1, but with H4 = 10 mm, an arteriovenous fistula vascular liner stent with an extended bifurcation tube is obtained, which can be cut as needed during the operation to meet individual needs.

[0048] Example 4: Similar to Example 1, but with rectangular cutouts on the support, resulting in a similar... Figure 4 The stent structure has a blank area that accounts for 50% of the total surface area in its unfolded diagram. The stent material is polylactic acid (PLA). Simultaneously, using PLA as a carrier, rapamycin is mixed at a weight ratio of 10% and dissolved in ethyl acetate to prepare a 3% concentration solution. This solution is ultrasonically sprayed onto the stent surface. After the solvent has completely evaporated, a drug-eluting arteriovenous fistula liner stent with a surface-loaded rapamycin is obtained. After implantation into the blood vessel, rapamycin is gradually released, inhibiting the proliferation of vascular endothelial cells and smooth muscle cells in contact with it, reducing the risk of intravascular restenosis, and prolonging the service life of the arteriovenous fistula. Simultaneously, the PLA stent body gradually degrades and is absorbed.

[0049] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stent liner for arteriovenous fistula vessels, characterized in that, The arteriovenous fistula lining stent has a three-way tube structure, which provides three branches to connect to the artery and vein respectively. The outer diameter of the stent matches the diameter of the vessel lumen. Two pathways in the three-way tube structure have their axes aligned to form a straight tube, while the axis of the third pathway forms a bifurcation tube with a variable angle to the straight line formed by the axes of the first two pathways. The straight tube and the bifurcation tube together form the three-way shape of the hollow stent, with optional additional structures near each port. The straight tube is used for implantation into the arterial vessel; the bifurcation tube is used to connect to the vein. The arteriovenous fistula lining stent meets the following conditions: The length of the straight tube in the arteriovenous fistula lining stent is H1. The length of the H2 segment is 0.1-0.9 times that of H1. The outer diameters D1 and D2 of the straight tube are 0.01-0.2 times the length of H1. D1 is the outer diameter of the straight tube end face away from the end of the bifurcation tube. D2 is the outer diameter of the straight tube end face near the end of the bifurcation tube. The H2 segment is the straight tube section between the end face of the bifurcation tube and the bottom of the contact end. If D1 and D2 are the same or different, and D1 and D2 are different, then the straight tube section forms a cone shape with a smooth and gradual change in outer diameter. The bifurcation tube is a section of arc tube with a radius of curvature R1, where R1 is 0.02-0.4 times H1, and the outer diameter D3 of the bifurcation tube is 0.01-0.2 times H1. The lower part of the contact end between the branch pipe and the straight pipe is tangent to the straight pipe, and the upper part of the contact end is provided with a fillet with a radius of R2 between it and the straight pipe. The size of R2 is 0.01-0.2 times that of H1. The axis perpendicular to the end face at the end of the bifurcated pipe forms an angle θ with the axis of the straight pipe. The angle θ ranges from 0 to π / 2 radians. The end of the arc pipe is also connected to a straight pipe with an outer diameter of D3 and a length of H4. The length of H4 is 0 to 0.9 times that of H1.

2. The arteriovenous fistula vascular liner stent according to claim 1, characterized in that, A number of grooves or protrusions are provided near each end face to facilitate the fixation of the blood vessel. The distance H3 from the specific end face to the location of the groove or protrusion is 0.01-0.9 times that of H1. The number of grooves or protrusions is 1-5. The depth of the groove or the height of the protrusion is 1 / 4-1 / 2 times the wall thickness.

3. The arteriovenous fistula vascular liner stent according to claim 2, characterized in that, The number of grooves or protrusions is 1-3.

4. The arteriovenous fistula vascular liner stent according to claim 1, characterized in that, The wall thickness of the arteriovenous fistula lining stent is 0.05-3 mm.

5. The arteriovenous fistula vascular liner stent according to claim 1, characterized in that, The arteriovenous fistula lining stent is either completely closed or has a certain degree of open structure. The specific open structure can be a round hole or any other arbitrary shape. It still has sufficient support under the open structure. When the open structure is formed, the proportion of the blank surface area of ​​the stent after it is unfolded to the total surface area of ​​the stent is 10-90%.

6. The arteriovenous fistula vascular liner stent according to claim 1, characterized in that, The material of the arteriovenous fistula vascular liner stent is a biomedical material that has been approved for implantation in blood vessels; the material of the arteriovenous fistula vascular liner stent is selected from any of the following materials: stainless steel, cobalt-chromium alloy, nickel-titanium alloy, platinum-chromium alloy, magnesium alloy, pure iron, silicone rubber, polyethylene, polytetrafluoroethylene, polyethylene terephthalate, polyacrylate, polyamide, polyether block polyamide, polyurethane, polycaprolactone, polylactic acid and its copolymers.

7. The arteriovenous fistula vascular liner stent according to claim 1, characterized in that, The arteriovenous fistula lining stent is either a drug-free stent made entirely of material or a drug-loaded stent.

8. The arteriovenous fistula vascular liner stent according to claim 1, characterized in that, The arteriovenous fistula lining stent is prepared by die casting, additive manufacturing or laser cutting methods.

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