Ankle brachial index as an independent predictor of mortality in anticoagulated atrial fibrillation

Background An abnormal ankle brachial index (ABI, the ratio of the ankle and the brachial systolic blood pressure) (= 0.90 or = 1.4) suggests the presence of peripheral arterial disease (PAD) and has proposed as a marker of cardiovascular risk. We hypothesised that the ABI would predict mortality and adverse events in anticoagulated chronic nonvalvular AF patients. Methods We recruited 287 consecutive anticoagulated outpatients with permanent or paroxysmal nonvalvular AF who were stabilised for 6 months on oral anticoagulation (Oral anticoagulation; INR 2.03.0). ABI was performed following a standard technique. Cox models were used to determine the association between ABI, and bleeding, cardiovascular events and mortality. Results Median ABI was 1.09 (0.931.23) and 78 (27%) had an abnormal ABI. Abnormal ABI was associated with diabetes, heart failure and ischaemic heart disease (P = 0.006, 0.019 and 0.009, respectively), and a CHADS2 score = 2 (P = 0.016). Median follow-up was 861 (7181016) days, during 21(7%) presented an adverse cardiovascular event, 23 (8%) major bleeding events and 18 (6%) died. ABI was an independent predictor for all-cause mortality, even after adjusting for CHADS2 score (Cox multivariable regression analysis, HR 2.76(1.087.06), P = 0.033). Abnormal ABI was significantly associated with major haemorrhagic events [HR: 2.47(1.016.04); P = 0.047], even after adjustment for HAS-BLED score. Conclusion Abnormal ABI is common in AF patients, and ABI was an independent predictor for all-cause mortality, even after adjusting for CHADS2 score. ABI was an independent predictor for major bleeding, even after adjusting for the HAS-BLED score. ABI could be a useful tool for improving risk stratification of anticoagulated AF patients.