INTRAVASCULAR ULTRASOUND ASSESSMENT OF DIRECT PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

Background Acute myocardial infarction is caused by sudden thrombotic occlusion of the coronary artery due to a previous rupture of atherosc lerotic plaque. Objective To use intracoronary ultrasound measurements to evaluate lumen and plaque changes in patients with acute myocardia l infarction. Methods Patients (n = 103) with acute myocardial infarct ion who had been scheduled to undergo primary percutaneous translumina l coronary angioplasty (PTCA) were selected. Both before and after suc cessful coronary angioplasty, intracoronary 30 MHz ultrasound studies were performed using a 3.5F monorail catheter. The ultrasound catheter was successfully advanced into the occluded vessel segment without ma jor complications prior to PTCA in 79 of 103 (76.7%) patients and afte r PTCA in 88 of 103 (85.3%) patients. Results The plaques were eccentr ic in 66 patients (83.5%). The plaque morphology was purely low echoge nic in 14 (17.7%), highly echogenic in six (7.6%) and mixed in 59 (74. 7%) patients. Partial (59 of 79, 74.7%) or ring-like calcification (3 of 79, 3.8%) was observed in 62 patients (78.5%). Plaque fissuring or dissection was detected prior to PTCA in 25 patients (31.7%). Coronary angioplasty successfully enlarged the inner luminal area from 2.1 +/- 0.7 to 7.4 +/- 1.9 mm(2) (P < 0.01), whereas the plaque-thrombus area decreased significantly (13.8 +/- 1.7 mm(2) before and 9.0 +/- 1.9 mm (2) after PTCA; P < 0.01). The total vessel area remained virtually co nstant (15.9 +/- 1.9 mm(2) before and 16.4 +/- 2.5 mm(2) after PTCA, N S). PTCA-induced plaque rupture or dissection was observed in only 13 (16.5%) patients. Conclusion Intracoronary ultrasound imaging can be p erformed safely and successfully prior and subsequent to PTCA in selec ted patients with acute myocardial infarction. Early reperfusion via P TCA seems to be attributable to a significant reduction in the amount of low-echogenic plaque and thrombus material, whereas factors like ba lloon-induced dissection and stretching of vessels play only a minor r ole. (C) Rapid Science Publishers ISSN 0954-6928.