Comparison of Coronary Plaque Components between Non-Culprit Lesions in Patients with Acute Coronary Syndrome and Target Lesions in Patients with Stable Angina: Virtual Histology-Intravascular Ultrasound Analysis

BACKGROUND AND OBJECTIVES: The differences in plaque characteristics between non-culprit lesions (NCL) in acute coronary syndrome (ACS) patients (ACS-NCL) and target lesions (TL) in stable angina (SA) patients (SA-TL) are not well understood. We used a virtual histology-intravascular ultrasound (VH-IVUS) to compare the plaque components between ACS-NCL and SA-TL. SUBJECTS AND METHODS: We compared VH-IVUS findings between 290 ACS-NCL and 276 SA-TL. VH-IVUS classified the color-coded tissue into four major components: green (fibrotic); yellow-green (fibro-fatty); white {dense calcium (DC)}; and red {necrotic core (NC)}. Thin-cap fibroatheroma (TCFA) was defined as a NC > or =10% of the plaque area in at least 3 consecutive frames without overlying fibrous tissue in the presence of > or =40% plaque burden. RESULTS: Although the plaque burden was significantly smaller (52+/-13% vs. 54+/-14%, p=0.044), ACS-NCL had a greater %NC area (17.9+/-11.6% vs. 14.3+/-8.7%, p<0.001) and %DC area (9.7+/-9.8% vs. 8.1+/-8.0%, p=0.032) compared with SA-TL at the minimum lumen site. By volumetric analysis, ACS-NCL had a greater %NC volume (15.8+/-9.2% vs. 13.9+/-7.4%, p=0.006) compared with SA-TL. TCFA was observed more frequently in ACS-NCL compared with SA-TL (27.6% vs. 18.1%, p=0.032). Independent predictors of TCFA by multivariate analysis were ACS {odds ratio (OR): 2.204, 95% CI: 1.321-3.434, p=0.021} and high-sensitivity C-reactive protein (OR: 1.101; 95% CI 1.058-1.204, p=0.035). CONCLUSION: Although the plaque burden was significantly smaller, ACL-NCL had more vulnerable plaque components compared with SA-TL, and ACS and high-sensitivity C-reactive protein were the independent predictors of TCFA.

Late Intravascular Ultrasound Findings of Patients Treated with Brachytherapy for Diffuse In-Stent Restenosis

BACKGROUND AND OBJECTIVE: The long-term effects of beta-irradiation on intimal hyperplasia (IH) within the stented segment and vessel, and the lumen dimensions of non-stented adjacent segments, have not been sufficiently evaluated in patients with ISR. The long-term (24 months) effects of beta-irradiation ((188)Re-MAG3-filled balloon) were evaluated using intravascular ultrasound (IVUS) in patients with in-stent restenosis (ISR). SUCJECTS AND METHODS: A two-year follow-up IVUS was performed in 30 patients with patent ISR segments at the 6-monthly follow-up angiography. Serial IVUS images were acquired at 5 equidistant intra-stent sites and 3 different reference segment sites (1, 2 and 4 mm from stent margin). RESULTS: The mean intra-stent IH area and IH burden significantly increased between 6 and 24 months-from 2.1+/-1.1 to 2.6+/-1.4 mm2 (p<0.001) and from 26+/-10 to 33+/-14% (p<0.001), respectively. There were significant decreases in the mean external elastic membrane (from 10.1+/-3.9 to 9.7+/-3.9 mm2, p=0.015) and lumen area (from 5.6+/-2.3 to 5.1+/-2.3mm2, p=0.021) within the distal reference segments between 6 and 24 months. Target lesion revascularization (TLR) was performed between 6 and 24 months in 6 patients (20%) following the beta-irradiation therapy. There were no significant differences between the TLR and non-TLR groups, with the exception of a smaller minimum lumen CSA at 24 months in the TLR group. CONCLUSION: Because of a small amount of late loss between 6 and 24 months, most irradiated ISR vessel segments remained stable for up to 2 years. However, quantitative evidence of late catch-up was evident in most patients and was significantly associated with 24-month TLR in some patients with a smaller minimum lumen area.