INTRAVASCULAR ULTRASOUND IMAGING IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

Myocardial infarction is the result of acute thrombotic occlusion of a coronary artery secondary to rupture of an atherosclerotic plaque. In tracoronary ultrasonic examinations (ICUS) were performed in patients with acute, myocardial infarction in order to describe intraluminal ul trasonic findings at the sire of an acute coronary occlusion. Coronary angiography and ICUS studies were performed consecutively within 6 h after the onset of chest pain in 50 patients with acute myocardial inf arction (AMI) prior to percutaneous coronary angioplasty (PTCA). Follo wing angiographic documentation of a proximal occlusion, a 35 mechanic al ultrasound catheter (30 MHz) was advanced successfully through the lesion in 42 of 50 patients (84%). In 37 of the 42 patients (88.1%), I CUS differentiated between pulsatile, low echogenic, intraluminal mate rial suggesting thrombus, and mural more highly echogenic atherosclero tic plaque. A negative imprint of the ICUS catheter was documented wit hin the low echogenic material in 25 of 42 (60%) patients with AMI. Lo w echogenic intraluminal material was found in 31 of 42 (73.4%) segmen ts proximal to the highly echogenic plaque and in 28 of 42 (66.7%) seg ments distal to it, indicating pre- and post-stenotic thrombus in AM1. Thr plaque appeared eccentric in 32 of 42 patients (76.2%) with AMI. Cross-sectional area stenosis due to highly echogenic plaque averaged 48+/-14%. Calcification of plaque was evident in 35 of patients (83.3% ) and the surface of tile plaque was rough in 30 of 42(42.4%), Fissure s were found in 10(23.8%) and a dissection was detected in four (9.5%) cases