Assessment of microvascular injury after acute myocardial infarction: importance of the area at risk.

Microvascular obstruction after acute myocardial infarction has been associated with adverse ventricular remodeling, arrhythmias, and poor clinical outcome. Hirsch et al. demonstrate a moderate concordance between abnormal intracoronary Doppler flow characteristics assessed in the cardiac catheterization laboratory and microvascular obstruction detected noninvasively by delayed-enhancement MRI. The results indicate, however, that coronary flow measurements might be insensitive to small amounts of microvascular obstruction, and suggest that considering the 'area at risk' is important in the evaluation of the severity and extent of myocardial damage.