Markers of myocardial reperfusion as predictors of left ventricular function recovery in acute myocardial infarction treated with primary angioplasty.

BACKGROUND: Myocardial blush grade (MBG), corrected TIMI frame count (cTFC), and ST-segment reduction are indices of myocardial reperfusion. HYPOTHESIS: We evaluated their predictive value for left ventricular (LV) function recovery by gated single-photon emission computed tomography (SPECT) after acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI).
METHODS: In 40 patients with AMI, gated SPECT was performed at admission and repeated 7 and 30 days after PCI. Left ventricular function recovery was defined as an increase > or = 10 points in SPECT LV ejection fraction from baseline to 1 month. The MBG, cTFC, and ST-segment elevation index 1 h after PCI were determined to evaluate reperfusion.
RESULTS: Twenty-four patients (Group 1) had LV function recovery and 16 (Group 2) did not. A significant correlation was found between LV function recovery and MBG (r = 0.66; p = 0.0001), and ST-segment elevation index at 1 h (r = -0.55; p = 0.0001), but not with cTFC. Univariate predictors of LV function recovery were MBG (p = 0.0003) and ST-segment elevation index 1 h after intervention (p = 0.0026), but not cTFC. In a multivariate analysis, MBG was the only predictor of LV function recovery. Myocardial blush grade > or = 2 and ST-segment elevation index reduction had the same accuracy (88%) for predicting LV function recovery. Lower accuracy (75%) was shown by fast cTFC (< 23 frames). Myocardial blush grade > or = 2 showed the better negative likelihood ratio, and ST-segment elevation index reduction had the higher positive likelihood ratio in predicting LV function recovery.
CONCLUSIONS: Myocardial blush grade was the best parameter for prediction of LV function recovery: MBG > or = 2 and ST-segment elevation index reduction showed good accuracy in predicting LV function recovery. The cTFC failed to be a significant predictor.