Lesion characteristics detected by intravascular ultrasound in patients with acute coronary syndrome and stable angina pectoris

Objective The purpose of the study was to investigate and compare the lesion characteristics in patients with acute coronary syndrome (ACS) and stable angina pectoris (SAP) using intravascular ultrasound (IVUS) imaging. Methods A total of 85 patients (male 59, mean age 59±10 yrs) who underwent IVUS (ClearView or Galaxy2, Boston Scientific, USA) examination of culprit lesions were enrolled in this study. Among them, 50 presented with ACS and 35 were diagnosed as SAP. IVUS analysis included qualitative assessment of culprit lesion and quantitative measurements of the vessel area (EEMcsa), the lumen area (Lcsa) and the plaque area (EEMcsa-Lcsa) of both the stenotic and reference segment. The remodeling index (RI) was defined as the ratio of lesion EEMcsa to mean reference EEMcsa. Positive remodeling was defined as RI1.0 and negative remodeling as RI1.0. The lesion characteristics in patients with ACS were compared with those in SAP. Results Culprit lesions of ACS patients were predominantly soft plaque (74% in ACS vs 31% in SAP, P =0.001). More plaque rupture (38% vs 8%, P =0.002) and thrombus formation (24% vs 0%, P =0.002) were observed in ACS patients compared with SAP patients. The EEMcsa (15.0±4.4 mm 2 vs 11.3±3.6 mm 2, P 0.001), plaque area (11.5±4.1 mm 2 vs 7.6±2.9 mm 2, P 0.001), plaque load (76.7%±10.4% vs 66.8%±12.6%, P 0.001) and the RI (1.05±0.11 vs 0.95±0.16, P =0.002) were significantly greater in lesions of ACS than those of SAP. Positive remodeling (67% vs 36%) was more frequent in ACS patients ( P =0.006). Most of the lesions were eccentric in both ACS and SAP patients (90% vs 83%, P =0.932). Conclusion The culprit lesions of ACS were mainly eccentric and soft plaque. More plaque rupture, thrombus formation, and positive remodeling were found in ACS patients compared with SAP patients.