BALTIMORE – Computed tomographic angiography can accurately and noninvasively measure the changes in overall and composition-specific plaque volume as a result of statin therapy.
At 1.2 years’ follow-up, there was a significant 38% decrease in total plaque volume in individuals on statin therapy compared with patients not on statin therapy. This difference remained significant after adjustment for age, gender, and conventional risk factors. Significant changes in noncalcified volume (a 73% decrease) and mixed-plaque volume (a 10% decrease) also were seen in those on statins compared with the nonstatin group. In addition, calcified plaque remained relatively stable, decreasing by 3.5% in the statin therapy group compared with the nonstatin group.
"Statin therapy was associated with a significant decrease in plaque volume, especially in noncalcified plaque volumes, and it was more prominent in women," Dr. Vahid Nabavi said at the annual meeting of the Society of Cardiovascular Computed Tomography.
Several cardiovascular imaging studies revealed that progression of coronary plaque volume over time is an independent predictor of cardiovascular mortality. Intravascular ultrasound (IVUS) provides high-resolution images capable of revealing early preclinical coronary artery disease. However, it is a highly invasive and expensive technique, and will be used only in conjunction with complex coronary interventions, noted Dr. Nabavi, who is a research fellow at the Los Angeles Biomedical Research Institute at Harbor–University of California, Los Angeles, Medical Center.
Quantitative measurements of coronary plaque made with cardiovascular CT angiography (CTA) correlate well with plaque measurements made using IVUS. Low-density noncalcified plaque on CTA correlates with necrotic core plus fibrofatty tissue on IVUS. CTA could be a less expensive, noninvasive alternative to IVUS, particularly for measuring changes in plaque associated with therapy, Dr. Nabavi noted.
In this study, 107 patients underwent serial, clinically indicated CTAs. Their mean age was 67 years, and 81% were men. The median follow-up was 1.2 years. The researchers collected data on risk factors, statin therapy, and laboratory findings.
They quantitatively measured the change in indexed total and composition-specific plaque volume of the target segment with luminal stenosis less than 50% in patients on statin therapy (40 mg of atorvastatin daily) or those with lifestyle changes only.
At baseline, there were no significant differences between groups in age, gender, clinical demographics, risk factors, or total and composition-specific plaque volumes. After adjustment, decreases in overall, mixed, calcified, and noncalcified plaque volumes between those on statins and those not on statins were 56%, 12%, 43%, and 144%. "More robust changes were seen in women," Dr. Nabavi said.
Dr. Nabavi did not report whether he had any conflicts of interest.