Acute myocardial infarction early viability assessment by 64-slice computed tomography immediately after coronary angiography: comparison with low-dose dobutamine echocardiography.

OBJECTIVES: Early evaluation of myocardial viability in acute myocardial infarction is useful to guide therapy. Therefore, we assessed 64-slice computed tomography (CT) immediately after coronary angiography in this setting.
BACKGROUND: Recent preliminary studies have shown the promising usefulness of late hyperenhancement multislice computed tomography (MSCT) for non-viability assessment.
METHODS: Thirty-six patients admitted for a first acute myocardial infarction had a coronary angiogram early after admission followed by 64-slice CT without iodine reinjection. The 16 segments of the left ventricle depicted by the American Society of Echocardiography were graded: no, subendocardial, or transmural hyperenhancement. No or subendocardial hyperenhancement were expected to reflect viability. Two to 4 weeks later, the same segments' contractility was evaluated at rest. Low-dose dobutamine echocardiography was performed in case of akinetic segment at rest.
RESULTS: Mean delay between coronary angiography and MSCT was 24 +/- 11 min (range 7 to 51 min). We compared 576 segments evaluated by each method. Agreement was noted for 560 segments (97%) and disagreement for 16 segments (3%). Thus, 64-slice CT after coronary angiography for an acute myocardial infarction had 98% sensitivity, 94% specificity, 97% accuracy, and 99% positive and 79% negative predictive values for detecting viable myocardial segments at a very early stage of an acute myocardial infarction. On a per-patient analysis, sensitivity, specificity, accuracy, and positive and negative predictive values were 92%, 100%, 94%, and 100% and 85%, respectively.
CONCLUSIONS: A 64-slice CT after coronary angiography for an acute myocardial infarction is a promising method for early evaluation of viable myocardium.