Optimal time for predicting myocardial viability after successful primary angioplasty in acute myocardial infarction: A study using myocardial contrast echocardiography

This study sought to elucidate serial changes in microvascular integrity du ring papaverine-induced hyperemia in the risk area for myocardial infarctio n. In addition, we attempted to determine the optimal time for predicting m yocardial viability. Seventy-two patients who underwent serial myocardial c ontrast echocardiography (MCE) before and shortly after (day 1), 1 day [day 2), and 3 weeks (day 21) after recanalization were studied. In 18 of 72 pa tients, MCE was performed at baseline and during hyperemia using selective intracoronary infusion of papaverine. Both the peak gray-scale ratio (PGSR) within the risk area, and the no- and low-reflow ratio (LR ratio) were ana lyzed in each stage. Left ventricular regional wall motion (RWM) was determ ined 6 months after recanalization. The correlation coefficient between PGS R with papaverine on day 1 and that on day 2 was 0.54 (p = 0.02); it was 0. 50 (p = 0.04) between day 1 and day 21 and 0.82 (p = 0.001) between day 2 a nd day 21. On day 1, the correlation coefficient between the LR ratio with papaverine and RWM was 0.60 (p = 0.02), which changed to 0.72 (p = 0.003) o n day 2 and 0.54 (p = 0.04) on day 21, respectively. The best time to predi ct viable myocardium was established on day 2 by receiver operating charact eristics curves. ST-segment re-elevation, elapsed time from onset to recana lization, and antecedent angina pectoris were independent factors for PGSR on day 2 using stepwise and multiple linear regression analysis. This study suggests that the optimal time to estimate microvascular integrity for pre dicting myocardial viability might be 1 day after recanalization, which is neither shortly after recanalization nor during the convalescent stage. (C) 2001 by Excerpta Medico, Inc.