Resting qualitative and quantitative myocardial contrast echocardiography to predict cardiac events in patients with acute myocardial infarction and percutaneous revascularization

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; beta, sec(-1); and A beta] 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, beta and A beta parameters compared to patients without events [1.84 +/- A 0.36 vs 1.39 +/- A 0.17 for PSI, P < 0.001; 0.57 +/- A 0.24 vs 0.85 +/- A 0.30 for A, P = 0.03; 0.34 +/- A 0.15 vs. 0.53 +/- A 0.17 for beta, P = 0.002; and 0.21 +/- A 0.12 vs. 0.49 +/- A 0.32, for A beta, P = 0.003; respectively]. A PSI value of 1.58 provided an area under the curve (AUC) of 0.873, while beta of 0.423 and A beta of 0.323 provided an AUC of 0.858 and 0.842, respectively. PSI and A beta 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, A beta) provides independent prediction of cardiac events.