Ankle-brachial index as short term and long-term predictor of cardiovascular events after myocardial infarction: a 3-year follow-up study

Objective: The ankle-brachial index (ABI) is a non-invasive index originally proposed for the diagnosis of lower-extremity peripheral artery disease. It is also a marker of atherosclerosis in other vascular sites and may serve as a prognostic marker for cardiovascular events even in the absence of PAD symptoms. However, data on the prognostic value of this index in the setting of acute myocardial infarction (MI) are scarce. Design and method: We prospectively evaluated 441 patients [79.4% male; average age 62 years, 67.6% hypertensive, 29.7% diabetes mellitus (DM); 54.9% STEMI] hospitalized for acute MI. Basic demographic, echocardiographic, peri- and postoperative details were recorded and analyzed. The ABI threshold used to define abnormal levels was less than or equal to 0.90 and recorded according to established guidelines using a certified automated device (ABPI MD, MESI®). The primary endpoint was a composite of all-cause and cardiovascular death, as well as major cardiovascular events including decompensated heart failure, new ACS, cerebrovascular event, malignant arrhythmia, PAD event and new onset renal dysfunction. All events were assessed both in-hospital and within 3 years of follow-up. Results: The mean ABI of our study population was estimated to be 1.1 (IQR: 1.00 to 1.18). In reduced multivariate regression models ABI was a prognostic indicator for the in-hospital composite endpoint. Particularly, patients with abnormal ABI showed a threefold risk of in-hospital events [HR 2.93, 95% CI: 1.48-5.81, p=0.002]. Regarding all-cause mortality, after multivariate analysis, ABI [HR 2.88, 95% CI: 1.53 – 5.42, p=0.001] maintained its predictive power regardless of hypertension, DM, LDL levels and smoking status of the study population in 3 years follow-up. Conclusions: In the setting of an acute MI, lower ABI values expose these patients to a higher risk of in-hospital events and are independently associated with long-term all-cause mortality. Consequently, ABI monitoring in patients with MI may identify patients with a higher risk profile and contribute to early clinical decision making.