Long-term outcomes of extra-anatomical venous bypass for central venous occlusion in haemodialysis patients: A single-centre experience

Objective: Central venous occlusion is a recognised complication of haemodialysis vascular access that can render ipsilateral arteriovenous fistulas dysfunctional. When endovascular options have been exhausted, extra-anatomical vein-to-vein bypass offers a surgical strategy for access preservation. This study evaluated long-term patency outcomes, bypass thrombosis natural history and baseline predictors of primary patency loss. Methods: A retrospective review was performed of all patients undergoing extra-anatomical venous bypass to the external iliac vein (EIV) for central venous occlusion at a tertiary vascular centre between 2016 and 2025. Kaplan–Meier analysis estimated primary, assisted-primary and secondary patency and freedom from bypass graft thrombosis. Cox proportional hazards regression using baseline variables identified predictors of primary patency loss. Results: Forty-six patients were included; median follow-up was 75.4 months. Primary patency was 76.1%, 45.7% and 19.6% at 1, 2 and 5 years. Assisted-primary patency was 91.1%, 79.7% and 43.7% at the same time points. Secondary patency was 98.0%, 92.9% and 90.4% at 1, 2 and 5 years. Reintervention for AVF or graft-vein anastomotic stenosis was required in 39 patients (84.8%). Bypass graft thrombosis occurred in 23 patients (50.0%); all underwent thrombectomy, of which 16 (69.6%) were salvaged. Graft infection occurred in four patients (8.7%), all requiring explantation. Six patients (13.0%) required fistula ligation for recurrent cannulation site bleeding. Total permanent access loss occurred in 17 patients (37.0%). On multivariable Cox regression, longer dialysis vintage (adjusted HR 0.87 per year, 95% CI 0.77–0.97, p = 0.016) was independently associated with reduced primary patency loss. Pre-operative access flow did not predict outcomes. Conclusions: Extra-anatomical venous bypass provides durable long-term access preservation for haemodialysis patients with central venous occlusion refractory to endovascular intervention. Although primary patency declines over time and reintervention burden is expected, secondary patency remains above 90% at 5 years in carefully selected patients.