Impact of multivessel coronary artery disease on early ischemic injury, late clinical outcome, and remodeling in patients with acute myocardial infarction treated by primary coronary angioplasty.

OBJECTIVE: The mechanism through which multivessel coronary artery disease (MVD) adversely affects the outcome of patients with ST-elevation myocardial infarction (STEMI) is poorly characterized. We assessed whether the impact of MVD on outcome of STEMI patients is because of ischemic damage after primary percutaneous coronary intervention (PPCI) or to late ischemic events. METHODS: From August 2005 to 2007, 288 STEMI patients treated by (bare metal) stent-PPCI were prospectively enrolled. The ischemic injury early after PPCI (evaluated by multiparametric approach) and the incidence of late adverse cardiovascular events were compared between the two groups. RESULTS: Compared with single vessel coronary artery disease, MVD patients (n=134) were older, with higher prevalence of diabetes, prior MI, anterior MI and higher collateral score. Myocardial perfusion as assessed by myocardial blush and SigmaST-segment resolution was similar in the two groups as well as the infarct size and microvascular obstruction as assessed by Troponin I and by the delayed enhancement of cardiac magnetic resonance. At clinical (98% complete) and echocardiogaphic (94% complete) follow-up (median 32 months) MVD patients showed a higher incidence of re-MI (6.1 vs. 1.3%), and urgent revascularization (8.3 vs. 2.7%) and worse left ventricular remodeling than single vessel disease patients. At propensity adjusted analysis MVD was an independent predictor of re-MI (odds ratio: 5.7) and ventricular remodeling (odds ratio: 2.2). CONCLUSION: The impact of MVD on clinical outcome and remodeling of STEMI patients is not because of the extent of ischemic damage observed after PPCI, but to recurrent ischemic events during follow-up.