Usefulness of ankle-brachial index calculated using diastolic blood pressure for prediction of mortality in patients with acute myocardial infarction

A low ankle-brachial index (ABI) calculated using systolic blood pressure (SBP) (ABIsbp) is associated with poor cardiovascular outcome in patients with acute myocardial infarction (AMI). ABI is always calculated using SBP clinically. However, there was no study investigating ABI calculated using mean artery pressure (MAP)(ABImap) and diastolic blood pressure (DBP)(ABIdbp) for mortality prediction in AMI patients. Therefore, our study was aimed to investigate the issue. 199 AMI patients were enrolled. Different ABIs were measured by an ABI-form device. The median follow-up to mortality was 64 months. There were 40 cardiovascular and 137 all-cause mortality. The best cutoff values of ABImbp and ABIdbp for mortality prediction were 0.91 and 0.78, respectively. After multivariate analysis, only ABIdbp and ABIdbp < 0.78 could predict cardiovascular mortality (P ≤ .047). However, all of six ABI parameters, including ABIsbp, ABImap, ABIdbp, ABIsbp < 0.90, ABImap < 0.91, and ABIdbp < 0.78, could predict all-cause mortality (P ≤ .048). In a direct comparison of six ABI models for prediction of all-cause mortality, basic model + ABIdbp <0.78 had the highest predictive value (P ≤ .025). In conclusion, only ABIdbp and ABIdbp < 0.78 could predict cardiovascular and all-cause mortality after multivariate analysis in our study. Furthermore, when adding into a basic model, ABIdbp < 0.78 had the highest additively predictive value for all-cause mortality in the six ABI parameters. Hence, calculation of ABI using DBP except SBP might provide an extra benefit in prediction of cardiovascular and all-cause mortality in AMI patients.