Upstroke Time Per Cardiac Cycle as A Novel Parameter for Mortality Prediction in Patients with Acute Myocardial Infarction

Background: Acute myocardial infarction (AMI) is one of the leading causes of death in the world. How to simply predict mortality for AMI patients is important because the appropriate treatment should be done for the patients with higher risk. Recently, a novel parameter of upstroke time per cardiac cycle (UTCC) in lower extremities was reported to be a good predictor of peripheral artery disease and mortality in elderly. However, there was no literature discussing the usefulness of UTCC for prediction of cardiovascular (CV) and overall mortality in AMI patients. Methods: 184 AMI patients admitted to the cardiac care unit were enrolled. Ankle-brachial index (ABI) and UTCC were measured by an ABI-form device in the same day of admission. Results: The median follow-up to mortality was 71 months. There were 36 CV and 124 overall mortality. Higher UTCC was associated with increased CV and overall mortality after multivariable analysis (P = 0.033 and P < 0.001, respectively). However, ABI was only associated with CV mortality and overall mortality in the univariable analysis but became insignificant after the multivariable analysis. In addition, after adding UTCC into a basic model including important clinical parameters, left ventricular ejection fraction, Charlson comorbidity index, and ABI, we found the basic model + UTCC had a better predictive value for overall mortality than the basic model itself (P < 0.001). Conclusions: Our study is the first one to evaluate the usefulness of UTCC in AMI patients for prediction of long-term mortality. Our study showed UTCC was an independent predictor of long-term CV and overall mortality and had an additive predictive value for overall mortality beyond conventional parameters. Therefore, screening AMI patients by UTCC might help physicians to identify the high-risk group with increased mortality.