The fate of the contralateral limb after major lower limb amputation for peripheral arterial disease or diabetes mellitus.

BACKGROUND: The contralateral limb is at risk after major lower limb amputation (MLLA) for peripheral arterial disease or diabetes mellitus due to the systemic nature of these diseases, with a subsequent bilateral MLLA required in over 10% of patients. The present study aims to determine the natural history of the contralateral limb after MLLA for peripheral arterial disease or diabetes. METHODS: A single-centre retrospective cohort study of patients undergoing MLLA for peripheral arterial disease or diabetes between January 2013 and July 2023 was performed. The primary outcome was clinically relevant contralateral limb disease (CR-CLD), defined as symptomatic disease of the contralateral limb or asymptomatic disease requiring prophylactic intervention. Statistical analysis used both survival analysis and competing risk modelling techniques. RESULTS: A total of 531 patients were included, with 175 (33%) going on to develop CR-CLD. The leading aetiology was chronic limb-threatening ischaemia, with 79.7% of these patients presenting with tissue loss. A total of 67% of CR-CLD presented by 1 year and 81% by 2 years after index MLLA. A diagnosis of diabetes, chronic peripheral arterial disease, ischaemic heart disease, and previous contralateral vascular intervention were identified as independent risk factors for the development of CR-CLD on multivariable analysis. A total of 72.6% of patients with CR-CLD underwent intervention, 28.6% of these requiring contralateral MLLA. For those not undergoing intervention, 56.3% were turned down due to co-morbidity or frailty. CONCLUSION: CR-CLD after MLLA is common, and presents early after index MLLA but with late-stage clinical disease. High-risk groups are identifiable. Outcomes are poor, with many patients undergoing a contralateral MLLA or being palliated.