Successful restoration of patency of the infarct-related artery is important in management of acute ST-segment elevation myocardial infarction (STEMI); however, it does not necessarily translate into the restoration of perfusion at the tissue level. In this study, we evaluate the prognostic role of qualitative and quantitative myocardial contrast echocardiography (MCE) in predicting cardiac events (after adjustment for cardiovascular risk factors) in STEMI patients undergoing reperfusion. Bedside resting real-time MCE using continuous infusion of diluted contrast agent (Definity) was performed within a median of 21.4 h from revascularization in STEMI. Myocardial perfusion on qualitative MCE was graded 1 = homogenous; 2 = partial/patchy; and 3 = absent. Perfusion score index (PSI) was calculated by adding the perfusion score in all segments divided by the total number of evaluable segments. Quantitative perfusion parameters [A, dB; β, sec(-1); and Aβ] were analyzed using a 17-segment model. Patients were followed for cardiac events including death; nonfatal myocardial infarction (MI); hospitalization for cardiac symptoms; coronary revascularization; or heart failure. Thirty-seven reperfused STEMI patients with a mean age of 64 years (range, 40-86 years) were enrolled and followed for a median of 1.4 years. Cardiac events occurred in 22 patients. Patients with cardiac events had a higher perfusion score index (PSI), and lower A, β and Aβ parameters compared to patients without events [1.84 ± 0.36 vs 1.39 ± 0.17 for PSI, P <0.001; 0.57 ± 0.24 vs 0.85 ± 0.30 for A, P = 0.03; 0.34 ± 0.15 vs. 0.53 ± 0.17 for β, P = 0.002; and 0.21 ± 0.12 vs. 0.49 ± 0.32, for Aβ, P = 0.003; respectively]. A PSI value of 1.58 provided an area under the curve (AUC) of 0.873, while β of 0.423 and Aβ of 0.323 provided an AUC of 0.858 and 0.842, respectively. PSI and Aβ were independent predictors of cardiac events with an adjusted hazard ratio of 3.41 (1.19-12.27); and 4.19 (1.3-19.09), respectively. No contrast-related side effects were reported. Evaluation of perfusion in reperfused STEMI patients by qualitative and quantitative MCE (myocardial blood flow, Aβ) provides independent prediction of cardiac events.
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