Lesion Characteristics in Patients with Acute Coronary Syndrome: A Comparison with Lesion in Patients with Stable Angina by Intravascular Ultrasound

Background and Objectives：The pathophysiology of acute coronary syndrome (ACS) is plaque rupture with thrombus formation, which is different from that of stable angina pectoris (SA). Intravascular ultrasound (IVUS) prior to percutaneous coronary intervention provides information on the plaques and vessel wall itself. The purpose of this study was to evaluate the lesion characteristics of ACS prior to coronary intervention compared to those of SA lesions by IVUS. Subjects and Methods：Pre-interventional IVUS was performed on 68 culprit lesions in 41 ACS and 25 SA patients. The plaque morphology, lumen and vessel sizes, and arterial remodeling pattern at the lesion segment were analyzed in both groups. A plaque rupture was defined as a plaque containing a cavity that communicated with the lumen, which was covered with a fibrous cap. Results：Positive remodeling was more frequent in patients with ACS than those with SA (42 vs. 11%), whereas negative remodeling was more frequent in patients with SA (22 vs. 41%) (p=0.023). Plaque rupture/dissection and thrombus was more frequent (51 vs. 19%, p=0.006 and 39 vs. 4%, p=0.001) in patients with ACS. Lesions with ACS had significantly larger EEM CSA, plaque CSA and plaque burden (p<0.05). There were no significant differences in the clinical parameters, angiographic parameters and plaque morphologies. Conclusion：Positive remodeling, plaque rupture/dissection and thrombus were more frequently observed in patients with ACS. In addition, lesions with ACS had a larger vessel size and a higher plaque burden. The type of remodeling, plaque rupture or dissection, thrombus and amount of plaques might have an impact on the clinical presentation. (Korean Circulation J 2004;34(6):548-557)