Influence of high-dose lipid lowering treatment compared to low-dose lipid lowering treatment on plaque composition assessed by intravascular ultrasound virtual histology in patients with ST-segment elevation acute myocardial infarction: the VIRHISTAMI trial.

AIMS: The aim of this study was to evaluate the effect of low-dose versus high-dose rosuvastatin therapy on the necrotic core (NC) content in coronary plaques of angiographic non-significant lesions as assessed by intravascular ultrasound - virtual histology. METHODS AND RESULTS: Eighty-seven statin-naive patients with ST-segment elevation myocardial infarction (STEMI) were randomised to 5 mg or 40 mg rosuvastatin. The volume of each plaque component (necrotic core, fibrous tissue, fibro-fatty, and dense calcium) was assessed at baseline and after 12 months of follow-up. Baseline low-density lipoprotein (LDL) cholesterol level was reduced by 31.8% in the low-dose group (from 3.1±0.7 mmol/l to 2.0±0.4 mmol/l, p<0.001) vs. 49.0% in the high-dose group (from 3.1±1.0 mmol/l to 1.6±0.7 mmol/l, p<0.001) (p=0.001 between groups). The plaque component necrotic core was reduced by 7.6% in the low-dose group (44.6±38.2 mm3 vs. 41.2±40.3 mm3, p=0.29) compared to 14.2% in the high-dose group (47.4±38.2 mm3 vs. 40.7±34.4 mm3, p=0.003) (p=0.38 between groups). CONCLUSIONS: In statin-naive patients with STEMI, rosuvastatin therapy for 12 months resulted in significant reduction in LDL-cholesterol; however, a significant decrease in necrotic core volume was only seen in the high-dose group.

Multicenter assessment of the reproducibility of volumetric radiofrequency-based intravascular ultrasound measurements in coronary lesions that were consecutively stented.

To assess in a multicenter design the between-center reproducibility of volumetric virtual histology intravascular ultrasound (VH-IVUS) measurements with a semi-automated, computer-assisted contour detection system in coronary lesions that were consecutively stented. To evaluate the reproducibility of volumetric VH-IVUS measurements, experienced analysts of 4 European IVUS centers performed independent analyses (in total 8,052 cross-sectional analyses) to obtain volumetric data of 40 coronary segments (length 20.0 ± 0.3 mm) from target lesions prior to percutaneous intervention that were performed in the setting of stable (65%) or unstable angina pectoris (35%). Geometric and compositional VH-IVUS measurements were highly correlated for the different comparisons. Overall intraclass correlation for vessel, lumen, plaque volume and plaque burden was 0.99, 0.92, 0.96, and 0.83, respectively; for fibrous, fibro-lipidic, necrotic core and calcified volumes overall intraclass correlation was 0.96, 0.94, 0.98, and 0.99, respectively. Nevertheless, significant differences for both geometrical and compositional measurements were seen. Of the plaque components, fibrous tissue and necrotic core showed on average the highest measurement reproducibility. A central analysis for VH-IVUS multicenter studies of lesions prior to PCI should be pursued. Moreover, it may be problematical to pool VH-IVUS data of individual trials analyzed by independent centers.

Effect of intensive lipid-lowering treatment compared to moderate lipid-lowering treatment with rosuvastatin on endothelial function in high risk patients.

BACKGROUND: The healthy endothelium plays a key roll in vascular regulation. This function can be examined non-invasively by use of B-mode ultrasound on the brachial artery. The aim of this study was to measure the effect of low-dose and high-dose lipid-lowering treatment with rosuvastatin on the endothelial function evaluated with endothelium-dependent and endothelium-independent flow-mediated dilatation (FMD). METHODS: 87 Statin-naive patients with ST-segment elevation myocardial infarction (STEMI) were randomized to 5mg or 40 mg rosuvastatin. The FMD was assessed at baseline, 6 months and after 12 months of follow-up by use of B-mode ultrasound of the brachial artery. RESULTS: Baseline low-density lipoprotein (LDL) cholesterol level was reduced by 31.8% in the low-dose group (from 3.1 ± 0.7 mmol/l to 2.0 ± 0.4 mmol/l, p<0.001) vs. 49.0% in the high-dose group (from 3.1 ± 1.0 mmol/l to 1.6 ± 0.7 mmol/l, p<0.001) (between groups p=0.001). Treatment with low-dose rosuvastatin did not change the endothelium-dependent FMD (-1.4 ± 8.2%, p=0.32) whereas the endothelium-dependent FMD increased significantly in the high-dose group (3.7 ± 11.0%, p=0.045) (between group p=0.029). No significant changes in endothelium-independent FMD were seen. CONCLUSION: In the present study treatment of statin-naive STEMI patients with high-dose rosuvastatin for 12 months resulted in a significant increase in endothelium-dependent FMD of the brachial artery whereas no significant change was seen in the low-dose rosuvastatin group (Clinicaltrials.gov Identifier: NCT01223625).

Between-centre reproducibility of volumetric intravascular ultrasound radiofrequency-based analyses in mild-to-moderate coronary atherosclerosis: an international multicentre study.

AIMS: To assess for the first time in a multicentre design the between-centre reproducibility of volumetric virtual histology intravascular ultrasound (VH-IVUS) measurements with a semi-automated, computerassisted contour detection system in mild-to-moderately diseased coronary segments. METHODS AND RESULTS: Analysts of four European IVUS centres performed independent IVUS analyses (in total 7,188 cross-sectional analyses) and obtained volumetric data to evaluate the reproducibility of volumetric VH-IVUS measurements in 36 coronary segments (length 20.0+/-0.4 mm) from patients with stable angina. Geometric and compositional VH-IVUS measurements were highly correlated for the different comparisons. Overall intraclass correlation for vessel, lumen, plaque volume and plaque burden were 0.98, 0.92 0.95, and 0.86, respectively; for fibrous, fibro-lipidic, necrotic core and calcified volumes overall intraclass correlations were 0.95, 0.93, 0.99, and 1.00, respectively. There were significant but small differences for vessel, lumen, fibrous and calcified volumes, and there was no significant difference for plaque volume. Of the plaque components necrotic core and calcified volume showed on average the highest reproducibility. CONCLUSIONS: These findings underline the necessity to centrally analyse IVUS data obtained in multicentre studies addressing mild-to-moderately diseased coronary arteries. In addition, pooling VH-IVUS data from different studies, analysed at different centres, may be problematical.

Comparison of intravascular ultrasound and angiographic assessment of coronary reference segment size in patients with type 2 diabetes mellitus.

During percutaneous coronary intervention, the reference segment is assessed angiographically. This report described the discrepancy between angiographic and intravascular ultrasound (IVUS) assessment of reference segment size in patients with type 2 diabetes mellitus. Preintervention IVUS was used to study 62 de novo lesions in 41 patients with type 2 diabetes mellitus. The lesion site was the image slice with the smallest lumen cross-sectional area (CSA). The proximal and distal reference segments were the most normal-looking segments within 5 mm proximal and distal to the lesion. Plaque burden was measured as plaque CSA/external elastic membrane (EEM) CSA. Using IVUS, the reference lumen diameter was 2.80 +/- 0.42 mm and the reference EEM diameter was 4.17 +/- 0.56 mm. The angiographic reference diameter was 2.63 +/- 0.36 mm. Mean difference between the IVUS EEM diameter and angiographic reference diameter was 1.56 +/- 0.55 mm. The mean difference between the IVUS reference lumen diameter and angiographic reference lumen diameter was 0.18 +/- 0.44 mm. Plaque burden in the reference segment correlated inversely with the difference between IVUS and quantitative coronary angiographic reference lumen diameter (slope = -0.12, 95% confidence interval -0.17 to -0.07, p <0.001), but it was not related to the absolute angiographic reference lumen diameter. Thus, reference segment diameters in type 2 diabetic patients were larger using IVUS than angiography, especially in the setting of larger plaque burden. In conclusion, these findings combined with inadequate remodeling may explain the angiographic appearance of small arteries in diabetic patients.