[Limitations of myocardial blush grade in the evaluation of myocardial perfusion in patients with acute myocardial infarction and TIMI grade 3 flow].

INTRODUCTION AND OBJECTIVES An analysis was made of variability in the measurement of the angiographic index blush between a university hospital and an independent core laboratory, as well as its correlation with perfusion analyzed by intracoronary myocardial contrast echocardiography (MCE) and the ventricular function at the sixth month. METHODS The study comprised 40 patients with a first ST-segment elevation myocardial infarction, single-vessel disease and open infarct-related artery. Perfusion was quantified by angiography (median fifth day, range 3-7) with blush in our laboratory and in an independent core laboratory. MCE was performed. Ejection fraction at the sixth month was determined with magnetic resonance imaging. RESULTS We found a weak correlation (r=0.38) between both laboratories. In the comparison of blush measurements concordance was 80%, kappa=0.43 if normality was defined by blush 2-3; and concordance 55%, kappa=0.1 for blush 3. Neither perfusion analyzed by MCE (r= 0.23, P=.2) nor ejection fraction by resonance (r=0.20, P=.3) did correlate to blush. CONCLUSIONS After infarction in patients with TIMI 3, variability is observed in blush measurements between a university hospital and an independent core laboratory, therefore it seems advisable to centralize blush measures in highly specialized core laboratories. A weak correlation was detected with perfusion analyzed by MCE and with late systolic function.