Background: Both surgical and endovascular treatment in elderly patients with critical limb ischemia are associated with high mortality rates. Patients with critical limb ischemia are at increased risk of adverse cardiovascular events and subsequent cardiovascular death. Little is known about the incidence and consequences of these adverse events. The aim of this study was to investigate the effect of adverse cardiac events on mortality in patients with critical limb ischemia undergoing surgical or endovascular treatment.Methods: A retrospective cohort study including all patients with critical limb ischemia aged >= 65 undergoing surgical or endovascular treatment for critical limb ischemia between January 2013 and June 2018 was conducted. Data on adverse cardiac events were collected from medical records. The effect of an adverse cardiac event on mortality during 6 months follow-up was analyzed with a multivariable cox proportional hazards model to adjust for confounders. Effects are displayed as hazard ratios (HR) with 95% confidence intervals (CI).Results: A total number of 449 patients were included. Median age was 76 years, 52.8% of patients were male. In total, 51 patients (11%) developed an adverse cardiac event, 31 patients (10%) in the surgical group and 20 patients (14%) in the endovascular group. After adjustment for confounders, adverse cardiac events were associated with an increased risk of mortality (HR 3.5 95% CI 2.1-5.9).Conclusions: This study showed that adverse cardiac events commonly occur in elderly patients with critical limb ischemia. Adverse cardiac events continue to occur even months after treatment and are associated with an increased mortality risk. These findings justify routine cardiac evaluation in both surgical and endovascular treatment. Additionally, frequent postdischarge cardiac follow-up in the outpatient clinic may be helpful in limiting the occurrence of adverse cardiac events.