Prediction of All-Cause Mortality and Cardiovascular Outcomes Using Ambulatory Arterial Stiffness and Ankle-Brachial Indices in Patients with Acute Myocardial Infarction: A Prospective Cohort Study

<b>Background/Objectives</b>: The ankle-brachial index (ABI) is a non-invasive diagnostic tool for peripheral artery disease (PAD) and a marker of systemic atherosclerosis, predictive of cardiovascular (CV) events. The ambulatory arterial stiffness index (AASI), derived from 24-h blood pressure monitoring, also predicts CV morbidity and mortality, particularly stroke. However, their combined prognostic utility in acute myocardial infarction (AMI) remains underexplored. This study aimed to assess the predictive value of ABI and AASI in patients with AMI. <b>Methods</b>: We conducted a single-center observational cohort study including 441 consecutive patients with AMI (79% male; mean age 62 years). ABI was measured using an automated device, with ≤0.9 defined as abnormal. AASI was calculated from 24-h blood pressure recordings. The primary endpoint was a composite of all-cause and CV death and major CV events, assessed in-hospital and over a 3-year follow-up. <b>Results</b>: Median ABI was 1.10 (IQR 1.00-1.18); 10.4% had abnormal ABI. Abnormal ABI was associated with a threefold higher risk of in-hospital adverse events (OR 2.93, 95% CI: 1.48-5.81, <i>p</i> = 0.002). In Cox regression, abnormal ABI predicted long-term all-cause mortality (HR 2.88, 95% CI: 1.53-5.42, <i>p</i> = 0.001), independent of traditional risk factors. Each 0.1 increase in AASI was linked to a 21% higher risk of the composite outcome (<i>p</i> = 0.001) and 25% increased risk of recurrent AMI or urgent revascularization (<i>p</i> = 0.001). <b>Conclusions</b>: In this prospective cohort of patients with AMI, ABI and AASI were associated with adverse outcomes, suggesting their potential role in risk stratification. These exploratory findings require validation in larger, multicenter cohorts to assess their incremental prognostic value and generalizability.