Background: This study aims to evaluate the safety and efficacy of a short-term, low dose, weight-based subcutaneous enoxaparin protocol (SEP) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis.
Methods: Prospective follow-up of 25 patients who presented to a tertiary institution with recurrent AV access thrombosis and treated with anticoagulation according to SEP following successful thrombectomy. Patency and safety outcomes of SEP were studied.
Results: The participants were 66.4 ± 10.2 years old and predominantly male (60%) and of Chinese ethnicity (72%). The AV accesses had a median age of 1.4 (0.6, 5.6) years with 60% being non-autogenous arteriovenous access while 40% were autogenous arteriovenous access. Thrombolytic agents (urokinase (72%) or alteplase (28%)) were used in all procedures while adjunct thrombectomy device was used in only four procedures. The mean dose of enoxaparin was 36.0 ± 8.2 mg or 0.64 ± 0.1 mg/kg/day for a mean duration 30.0 days (Interquartile range: 27.5, 31.0). One patient developed minor bleeding episode. Kaplan-Meier analysis demonstrated that the mean thrombosis-free survival pre- versus post-SEP adoption was 27.3 (95% CI 17.9-36.7) versus 183.5 (95% CI 100.1-266.9) days (p < 0.001). After adjusting for the type of thrombolytic agent, use of adjunct thrombectomy device, cutting balloon, drug-coated balloon, and stent graft, SEP remained a significant factor associated with longer thrombosis-free patency (HR 0.166: 95% CI 0.070-0.392, p < 0.001).
Discussion: SEP appears to be a feasible and safe thromboprophylaxis method to improve thrombosis-free patency for AV access with recurrent thrombosis.
Keywords: AV fistula; Recurrent arteriovenous access thrombosis; access patency; dialysis access; enoxaparin; lower molecular weight heparin; prosthetic grafts; thrombectomy and thrombolysis; thromboprophylaxis.