Usefulness of myocardial blush grade early and late after primary coronary angioplasty for acute myocardial infarction in predicting left ventricular function.

This study sought to analyze the evolution of myocardial perfusion during follow-up after primary angioplasty for acute myocardial infarction (AMI) and relate it to final left ventricular (LV) function. In 101 patients with a first AMI, angiographic myocardial blush grade (MBG) was analyzed immediately after intervention and at follow-up 7.5 +/- 5.6 months later. Cine ventriculography was performed at follow-up angiography to define LV function. Five patients had occluded stents or flow-limiting restenosis. In the remaining patients, myocardial perfusion at follow-up, as defined by MBG, was persistently abnormal in 19 patients (20%), had become normalized from previously abnormal MBG in 30 patients (31%), remained normal in 40 patients (42%), and deteriorated from normal to abnormal in 7 patients (7%). Patients with improvement of abnormal blush determined immediately after intervention to normal blush at follow-up (n = 30) compared with patients with persistently abnormal blush (n = 19) had a better LV ejection fraction at follow-up (53.7 +/- 11.1 vs. 37.4 +/- 9.7%, p <0.001). Evolution of MBG had a better predictive value for LV ejection fraction at follow-up than acute MBG only. Multivariate analysis proved evolution of MBG from AMI to follow-up to be an independent predictor of LV function (R(2) = 0.177, p <0.001) in addition to the initial size of jeopardized myocardium as defined by the sum of ST-segment elevation (R(2) = 0.138, p = 0.001) and infarct location (R(2) = 0.044, p = 0.033). In conclusion, tissue reperfusion after angioplasty for AMI is characterized by frequent improvement over time, as indicated by repeated MBG analysis. Patients with recovery of perfusion have better, final LV function.