Virtual histology findings and effects of varying doses of atorvastatin on coronary plaque volume and composition in statin-naive patients: the VENUS study.

BACKGROUND: While statin induces plaque regression, its effects, particularly with different doses on plaque virtual histology composition, remain unknown. METHODS AND RESULTS: In this prospective, randomized, double-blinded study, 40 consecutive statin-naive patients with stable angina requiring percutaneous coronary intervention (PCI) were randomized to 2 arms (20 patients each) receiving 6 months of atorvastatin 10 mg or 40 mg daily. The primary end-point was (VH-IVUS) changes from baseline to 6 months, as assessed by a core laboratory. Fifty-four VH-IVUS lesions were analyzed from the 10 mg group and 57 from the 40 mg group. Overall, plaque volume was reduced by 4.28% (-5.10±14.93 mm(3), P<0.001), absolute VH-IVUS fibrous volume by 10.54% (-4.87±10.74 mm(3), P<0.001), and relative percentage fibrous component by 3.29±7.84% (P<0.001), while relative percentage dense calcium increased by 1.50±3.08% (P<0.001), and necrotic core by 3.19±7.82% (P<0.001). Beneficial changes were more substantial in the higher dose (40 mg) group, with significantly more percentage plaque volume regression (-1.50±3.85% vs. 0.38±4.05% increase in the 10 mg group, P=0.014), less relative percentage necrotic core expansion (1.68±7.57% vs. 4.78±7.82% in the 10 mg group, P=0.037), and without occurrence of major adverse cardiac events (vs. 6 patients in the 10 mg group, P=0.020). CONCLUSIONS: In statin-naive patients requiring PCI, 6 months of atorvastatin induced a significant percentage of plaque volume reduction and substantial modification of VH-IVUS composition. In addition, these effects appeared to vary with different doses of atorvastatin, showing significantly better limitation of relative percentage necrotic core expansion at a higher dose.

Virtual histology by intravascular ultrasound study on degenerative aortocoronary saphenous vein grafts.

Data of virtual histology (VH) acquired by intravascular ultrasound (IVUS) on saphenous vein graft (SVG) lesions is lacking. This study sought to report the VH IVUS findings in degenerative aortocoronary SVG lesions and correlate various types of plaque compositions (fibrous, fibro-fatty, dense calcium, and necrotic core) with different clinical and lesion characteristics. Virtual histology IVUS was performed on SVG in 38 symptomatic patients with a history of coronary artery bypass grafting, who underwent percutaneous coronary intervention on either native vessels or SVG. Measurements were made at the image slice with the smallest lumen. A total of 54 SVG lesions were analyzed; the mean graft age was 13.7 +/- 4.0 years. The mean vessel size was 5.0 +/- 1.0 mm; plaque area was 13.4 +/- 7.3 mm(2), and plaque burden was 63.0% +/- 15.0%. Fibrous tissue represented the major plaque component (62.1% +/- 17.1%). Lesions with a plaque burden of >or=70% were associated with positive remodeling, larger vessel size, higher percentage of fibro-fatty tissue, but lower percentage of dense calcium. Plaque burden was found to be positively correlated with remodeling index (r = 0.37, P = 0.01) and % fibro-fatty tissue (r = 0.49, P < 0.001) but negatively correlated with % dense calcium (r= -0.31, P = 0.03). The severity of SVG atherosclerosis paralleled with a proportional increase in fibro-fatty tissue. Unstable plaques in SVG were associated with positive remodeling, lipid-rich atheroma, and less calcium deposition, similar to the VH IVUS findings in native coronary arteries.