WHAT THIS PAPER ADDSThis large, population based linked data study demonstrates that the accumulation of multiple peri-operative complications, including stroke, acute renal failure, delirium, and cardiac events, are associated with a progressive increase in the combined outcome of amputation and death after open or endovascular surgery for peripheral artery disease. While the association between peri-operative complications and short term adverse events is well recognised, this study found increased risks up to two years after surgery. Furthermore, patients with multiple complications had almost double the long term risk compared with those with one complication.Objective: To determine, in a population based linked data study, the relationship between peri-operative multiple complications and longer term outcomes, specifically the combined outcome of two year amputation or death, after lower limb revascularisation for peripheral artery disease (PAD). Methods: State wide health administrative data and death records were probabilistically linked for all patients who had lower limb artery surgery between 2010 and 2012 in New South Wales, Australia. Multivariable Cox regression modelled the impact of medical and surgical complications on the combined outcome of amputation or death two years after discharge. Results: Open surgery was performed on 3004 patients (26.7%), and endovascular on 8263 (73.3%). Of the 10 971 patients discharged alive, 3747 (34.1%) experienced at least one complication, and 2113 (19.3%) had multiple complications. Older patients, those with high comorbidity scores, or those with chronic limb threatening ischaemia were at increased risk of multiple complications. After adjusting for procedure type, patients with multiple complications experienced more than three times the hazard ratio (HR) of amputation or death two years after the procedure than those without complications (adjusted HR 3.4, 95% confidence interval 3.1e3.7), and increasing complications progressively multiplied the risk. In particular, non-surgical complications such as stroke, acute renal failure, delirium, and cardiac events were associated with the highest rates of two year amputation or death. Conclusion: Multiple complications after surgery for lower limb PAD carried a compounding risk of reduced long term amputation free survival. Patients experiencing at least one complication form a high risk group that requires increased attention to prevent the potential development of further complications.