The Solaris DE Sirolimus-Eluting Covered Stent for the Treatment of AV Access Stenosis or Occlusion

Inclusion Criteria: 1. Male or female, aged ≥ 18 years on the date of inclusion. 2. Has a mature AVF or AVG in the arm that was created ≥ 30 days before the initial procedure and is in use for dialysis therapy. 3. Subject has clinical and/or hemodynamic evidence of a venous flow obstruction or AV fistula or graft dysfunction. 4. Provides written informed consent prior to any study-specific procedures. 5. Is willing to submit to all follow-up evaluations accordingly with the specified schedule over 24 months. Angiographic Inclusion Criteria: 1. The target lesion is localized: 1. On an arm (including the cephalic arch) in an individual with AVF, and not on the cannulation segment (needling zone), OR 2. On anastomosis or juxta-anastomosis in an individual with VAS. The juxta-anastomosis is defined as a location such that the stent graft crosses the venous anastomosis. 2. The target lesion involves a de novo stenotic lesion or restenosis. 3. The target lesion is ≥ 5 cm from the arterial anastomosis. 4. The target lesion originates ≥ 3 cm of the cannulation segment (needling zone). 5. The target lesion has ≥ 50% stenosis by the operator's visual estimate. 6. The diameter of the distal reference vessel/graft is between 4.0 mm and 9.0 mm. 7. The target lesion should be ≤ 8 cm in total length by the operator's visual estimate. 8. Single or multiple target lesions may be covered by a single or two overlapping stents, provided that they are treated as a single lesion with a maximum length of 8 cm. 9. There was a successful predilation of the target lesion, defined as crossing the guidewire resulting in full expansion of the predilation balloon. 10. It presents up to 1 (one) non-target lesion in the access circuit requiring intervention in the initial procedure. The non-target lesion must be at least 10 cm away from the target lesion. The non-target lesion can only be treated with standard PTA. 11. The non-target lesion was successfully treated at the time of the initial procedure (success measured as ≤30% residual stenosis and no complications). 12. It does not have an endoprosthesis or has been in the access circuit for ≥ 30 days since placement and patent with ≤ 30% stenosis and is located ≥ 5 cm from the target lesion. Exclusion Criteria: 1. Pregnant, breastfeeding or intending to become pregnant in the next year. 2. Presents with any planned major endovascular or surgical procedure (including in the access loop) within 30 days of the initial procedure. 3. Planned surgical revision of the access site. 4. Known or suspected hemodialysis access site infection, systemic infection, and/or septicemia. 5. Patients on immunosuppressive therapy. 6. Known active coagulopathy or bleeding diathesis. 7. Known hypersensitivity to nickel titanium alloy, contrast or Sirolimus. 8. Contraindication to antiplatelet, anticoagulant, or thrombolytic therapies. 9. Known allergy to contrast agents or medications administered to perform endovascular intervention that cannot be adequately premedicated. 10. Life expectancy less than 12 months. 11. It is anticipated that the individual's hemodialysis access will be abandoned within 6 months. 12. The patient is participating in another research study involving an investigational product (pharmaceutical, biologic, or medical device). 13. The patient has a permanent central venous catheter (CVC) for dialysis access, except when the use is temporary, as a bridge to treatment through the access circuit and there is a plan for removal after a successful dialysis session after the initial procedure. Angiographic Exclusion Criteria: 1. Has a stent or stent graft located at any point in the AV access circuit that is not patent (\> 30% stenosis) or implanted \< 30 days. 2. The target lesion is \< 5 cm from the arterial anastomosis. 3. It was not possible to perform predilation of the target lesion to be treated with Solaris DE. 4. There was dissection/rupture of the treated vessel during the initial treatment that could not be controlled. 5. There is evidence of an aneurysm, pseudoaneurysm, or acute thrombus in the target lesion. (Note: The aneurysm or pseudoaneurysm present at the access but outside the target lesion can be treated during the initial procedure. Patients with acute thrombus can only be included after 15 days of thrombus treatment). 6. The target lesion is, and/or Solaris DE would be placed anywhere: 1. In the elbow region and joint 2. In a region that causes bending of the stent graft or bone protrusion over it 3. In the cannulation segment (needling zone) 4. Within any part of a pre-existing stent/stent graft (except for the arteriovenous graft of the access) 5. Lower End 6. Non-synthetic graft 7. Central thoracic veins located proximally to the arch of the cephalic vein. 7. The subject has more than one (1) non-target lesion (≥ 50% stenosis) that requires intervention in the initial procedure.