Factors associated with infrainguinal bypass graft patency at 1-year; a retrospective analysis of a single centre experience

Introduction: The aim of this study was to identify factors associated with primary graft patency 1 year following open lower limb revascularisation (LLR) at a tertiary referral vascular service. Methods: A retrospective analysis of patients undergoing infra-inguinal bypass surgery between January 2016 and May 2017 at a tertiary vascular centre (St Mary's Hospital, London) was performed. Data regarding patient demographics, comorbidities, type of operation and post-operative anti-thrombotic strategy were collected. Quality of run-off score was assessed from pre-operative imaging. Results: Seventy-seven cases were included in the analysis. Overall, the primary patency rate at 1-year was 63.6% (n = 49/77) and the secondary patency rate was 67.5% (n = 52/77). Independent variables with statistically significant inferior patency rates at 1-year were (1) bypasses with below knee targets (p = 0.0096), (2) chronic limb threatening ischaemia indication (p = 0.038), (3) previous ipsilateral revascularisation (p < 0.001) and (4) absence of hypertension history (p = 0.041). There was also a trend towards significance for American Society of Anesthesiologists (ASA) grade (p = 0.06). Independent variables with log-rank test p values of <0.1 were included in a Cox proportional hazards model. The only variable with a statistically significant impact on primary patency rates was previous open or endovascular ipsilateral revascularisation (HR 2.44 (1.04-5.7), p = 0.04). Conclusion: At 1-year follow-up, previous ipsilateral revascularisation was the most significant factor in affecting patency rates. Patients in this subgroup should therefore be deemed high-risk, which should be reflected in the informed consent and peri-operative management.