Ankle-Brachial Index in patients with acute myocardial infarction.

Background: Ankle-Brachial Index (ABI) has been validated for the diagnosis and risk stratification of vascular disease in the healthy population. The prognostic role and predictors of ABI in patients with established coronary artery disease still remain debated, and especially among patients with acute myocardial infarction (AMI) and represented therefore the aim of the present study.

Methods: We included patients undergoing coronary angiography and PCI for AMI in a single center from May 2022 to November 2024 and with no established history of peripheral arterial disease. ABI was measured before discharge in a phase of hemodynamic stability. Peripheral Arterial Disease (PAD) was defined for ABI ≤0.90.

Results: Overall, 130 patients with AMI were included, of whom 28 (21.5%) had impaired ABI values. No clinical or demographic difference was observed according to ABI, but for lower platelet count (216.7±52.9 vs. 264.8±86.9, P=0.006), that emerged as the only independent predictor of impaired ABI (OR=0.989 [95% CI: 0.982-0.997], P=0.007). Patients with higher platelet count (III tertile, >267.6×103/µL, N.=44) displayed significantly higher white blood cells count (P<0.001) and lower use of acetylsalicylic acid (P=0.06). At multivariable regression analysis, we confirmed the independent association between higher platelet tertiles values and impaired ABI (adjusted OR=0.147 [95% CI: 0.037-0.576], P=0.006).

Conclusions: Among patients with acute myocardial infarction, abnormal values of ABI are common, although similarly distributed across major established cardiovascular risk factors. In fact, platelet count emerged as the only independent predictor of impaired ABI and the inverse association between higher platelet count and ABI values was confirmed in different higher-risk subsets of patients. Future dedicated large-scale studies could provide the prognostic implications and more insightful understanding of our findings.