Angiographic assessment of reperfusion in acute myocardial infarction by myocardial blush grade

Abstract

Background - Angiographic successful reperfusion in acute myocardial infarction has been defined as TIMI 3 flow. However, TIMI 3 flow does not always result in effective myocardial reperfusion. Myocardial blush grade (MBG) is an angiographic measure of myocardial perfusion. We hypothesized that optimal angiographic reperfusion is defined by TIMI 3 flow and MBG 2 or 3. Methods and Results - In 924 consecutive patients with TIMI 3 flow after angioplasty for acute myocardial infarction, we prospectively studied the value of MBG. End points were death, MACE, enzymatic infarct size, and residual left ventricular ejection fraction. Follow-up was 16±11 months. Of the 924 patients, 101 (11%) patients had MBG 0 or 1. Mortality was significantly higher in patients with MBG 0 or 1 compared with patients with MBG 2 or 3 (relative risk, 4.7; 95% CI, 2.3 to 9.5; P<0.001). The combined incidence of MACE was higher in patients with MBG 0 or 1 compared with patients with MBG 2 or 3 (relative risk, 1.8; 95% CI, 1.1 to 2.8; P=0.009). Enzymatic infarct size was larger (1437±2388 versus 809±1672, P=0.001) and left ventricular ejection fraction was lower (37.7±10.6 versus 43.8±11.1, P<0.001) in patients with MBG 0 or 1 compared with patients with MBG 2 or 3. Conclusions - MBG is a strong angiographic predictor of mortality in patients with TIMI 3 flow after primary angioplasty. Enzymatic infarct size is larger and residual left ventricular ejection fraction is lower in patients with MBG 0 or 1 compared with MBG 2 or 3. Angiographic definition of successful reperfusion should include both TIMI 3 flow as well as MBG 2 or 3.