Ankle brachial index,a non invasive tool predicts cardiovascular events after acute myocardial infarction:a 3 year follow -up study

Abstract Background / Introduction The ankle-brachial index (ABI) is a non-invasive tool that was initially used for the diagnosis of lower-extremity peripheral artery disease (PAD). It has been proven that ABI is a marker of atherosclerosis in other vascular sites and can therefore be used to predict cardiovascular events regardless the presence or not of PAD symptoms. Purpose This study aims to examine the prognostic value of ABI in the setting of acute myocardial infarction (MI), as up till now there is not enough relevant evidence. Method We followed up 441 patients [79% male;mean age 62 years;67% hypertnesive; 30% with diabetes mellitus (DM); 52% current smokers] who were hospitalized because of MI for a period of three years. All patients underwent baseline estimation of clinical and laboratory parameters during theri hospitalization.The ABI was measured according to established methodology using a certified automated device and abnormal ABI defined as a value ≤ 0.9. The primary endpoint was a composite of all-cause and cardiovascular death, as well as major cardiovascular events including decompensated heart failure, new acute coronary syndrome, 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 Our study population had a mean ABI of 1.1 (IQR: 1.00 to 1.18). With the use of reduced multivariate regression models ABI was proven to be a prognostic indicator for the in-hospital composite endpoint. Patients with an abnormal ABI had a threefold risk of in-hospital events [HR 2.93, 95% CI: 1.48-5.81, p=0.002]. After conducting multivariate analysis ABI maintained its predictive power of all-cause mortality [HR 2.88, 95% CI: 1.53 – 5.42, p=0.001], regardless of hypertension DM, LDL levels and smoking status of the study population in 3 years follow-up. Conclusion An impaired ABI is associated with greater risk of in-hospital events in patients with acute MI. Moreover, ABI emerges as an independent predictor of long-term all-cause mortality in those patients.The findings of this study suggest that subclinical and clinical PAD are associated with poor outcomes among patients with acute MI; thus, routine ABI tests enhance risk stratification and might carry important prognostic significance in these patients regardless of PAD symptoms.