Predicting Late Myocardial Recovery and Outcomes in the Early Hours of ST-Segment Elevation Myocardial Infarction: Traditional Measures Compared With Microvascular Obstruction, Salvaged Myocardium, and Necrosis Characteristics by Cardiovascular Magnetic Resonance

Abstract

The aim of this study was to determine whether a very early imaging strategy improves the prediction of late systolic dysfunction and poor outcomes in ST-segment elevation myocardial infarction (STEMI) compared with traditional predictors. Earlier prediction of poor outcomes after STEMI is desirable, because it will allow tailored therapy at the earliest possible time, when benefits might be greatest. One hundred and three patients with acute STEMI were studied by contrast-enhanced cardiovascular magnetic resonance within 12 h of primary angioplasty and at 6 months and followed >2 years. The primary end point was left ventricular (LV) dysfunction, whereas poor outcomes were a key secondary end point. Traditional risk factors were only modest predictors of late LV dysfunction. Late gadolinium enhancement (LGE) volume maintained a stronger association to LV ejection fraction change than infarct transmurality, microvascular obstruction, or myocardial salvage during STEMI (p = 0.02). Multivariable logistic regression identified LGE volume during STEMI as the best predictor of late LV dysfunction (odds ratio: 1.36, p = 0.03). An LGE >or=23% of LV during STEMI accurately predicted late LV dysfunction (sensitivity 89%, specificity 74%). The LGE volume provided important incremental benefit for predicting late dysfunction (area under the curve = 0.92, p <or= 0.03 vs. traditional risk factors). Twenty-three patients developed poor outcomes (1 death, 2 myocardial infarctions, 5 malignant arrhythmias, 4 severe LV dysfunction <35%, 11 hospital stays for heart failure) over 2.6 +/- 0.9 years; LGE volume remained a strong independent predictor of poor outcomes, whereas LGE >or=23% carried a hazard ratio of 6.1 for adverse events (p < 0.0001). During the hyperacute phase of STEMI, LGE volume provides the strongest association and incremental predictive value for late systolic dysfunction and discerns poor late outcomes.