Demonstration of Recanalized Left Coronary Artery after Thrombolysis by Transthoracic Echocardiography

Abstract

Demonstration of recanalized coronary artery is mostly done by angiographic techniques. Early bedside demonstration of reperfusion after thrombolysis by transthoracic echocardiography (TTE) has important implications in the subsequent risk stratification and timing of coronary interventions. In this study, 12 patients with acute anterior myocardial infarction who received thrombolytic therapy were studied. Echocardiographic Doppler evaluation of left main coronary artery, proximal left anterior descending coronary artery (LAD), and proximal left circumflex coronary artery were studied before, during, and after thrombolytic therapy. Coronary flow in these arterial segments was assessed both by color flow and velocity measurements. These results were compared with coronary angiographic studies performed within 30 minutes to 48 hours of thrombolysis. Blood flow in left main coronary artery, LAD, and left circumflex coronary artery could be assessed in 9 patients. There was no demonstrable flow in LAD in 6 patients before thrombolysis. In 7 patients flow could be demonstrated in LAD after thrombolysis within 15 minutes to 6 hours. The peak flow velocity in LAD at a localized area of turbulence postthrombolysis varied from 1.8 to 4.5 m/s. One patient showed mosaic color flow in left main coronary artery with a peak velocity of 1.9 m/s before thrombolysis that improved to a laminar flow with a peak velocity of 1.0 m/s after thrombolysis. Two patients showed normal flow in proximal LAD, but no flow in mid-LAD. Two patients did not show any flow in LAD even after 12 hours of thrombolysis. There was good correlation of site of critical narrowing in LAD by TTE with coronary angiography in 6 patients. In 3 patients absent flow in mid-LAD by TTE correlated with total occlusion of either proximal (one patient) or mid-LAD (two patients). Demonstration of recanalized infarct-related left coronary artery soon after thrombolytic therapy is feasible. Locating the actual site of critical narrowing at bedside by TTE has important implications in the subsequent treatment of patients with acute anterior wall myocardial infarction.