Endovascular Salvage of Native Arteriovenous Fistulas: Post-Intervention Primary and Cumulative Patency Outcomes in a Colombian Regional Referral Center

INTRODUCTION: Arteriovenous fistulas (AVFs) are the preferred vascular access for hemodialysis due to superior patency and lower complication rates. However, access dysfunction caused by stenosis and thrombosis remains frequent, requiring repeated interventions. Endovascular techniques have emerged as the first-line approach for AVF salvage, although real-world data from Latin America are limited. The objective of this study is to characterize clinical, anatomical, and procedural features of patients undergoing endovascular AVF salvage and to evaluate postintervention primary, assisted primary, and cumulative patency, as well as overall survival. METHODS: We conducted a retrospective observational study at a regional referral center in Colombia (January 2023-June 2025), including all adult patients undergoing endovascular salvage of arteriovenous fistulas (AVFs). Patients without salvage, with incomplete data, or under 18 years were excluded. Data were collected from electronic medical records and included demographic, clinical, anatomical, and procedural variables. Patency was assessed using a post-intervention approach, with time zero defined as the first endovascular procedure. Kaplan-Meier analysis was used to evaluate event-free survival (access loss or death) and overall survival, with follow-up censored at January 31, 2026. Descriptive and non-parametric statistical analyses were performed using RStudio (2024.12.1 + 563). The study was approved by the institutional ethics committee. RESULTS: Fifty-nine patients (mean age 59 ± 13 years; 42/59 [71.2%] male) underwent 95 interventions. Hypertension (56/59 [94.9%]) and diabetes (27/59 [45.8%]) were the most common comorbidities. Brachiocephalic fistulas (44/59 [72.9%]) and left-sided access (39/59 [66.1%]) predominated. Technical success was achieved in all patients at the index intervention (100%). The mean interval between subsequent interventions was 162 days (5.4 months). Postintervention primary patency was approximately 65-70% at 180 days and declined progressively over time. Postintervention cumulative patency remained higher, with 75% at 600 days, 65-70% at 1000 days, and 30% at 1400-1500 days. No significant differences were observed by sex or treatment technique. Overall survival remained above 80% at 600 days and decreased gradually thereafter. CONCLUSIONS: Endovascular salvage of native arteriovenous fistulas is a feasible and effective strategy for preserving access function in a real-world clinical setting. Cumulative patency outcomes support the role of repeated endovascular interventions as a sustainable approach to prolonging access usability over time. While endovascular salvage appears associated with maintained patency, this relationship is likely influenced by underlying disease complexity and confounding by indication. These findings underscore the need for ongoing surveillance programs, standardized post-procedural pharmacological management, and further prospective studies to optimize long-term AVF outcomes in resource-limited settings.