Effects of statin therapy on non-calcified coronary plaque assessed by 64-slice computed tomography

Computed tomography angiography (CTA) enables characterization of non-calcified coronary atherosclerotic lesions (NCALs) and assessment of plaque vulnerability. We investigated whether the characteristics of NCALs detected by 64-slice CTA were influenced by preceding statin therapy and serum lipid profiles.

Among 493 consecutive patients who underwent coronary CTA, we enrolled 114 patients with NCALs. We divided the patients into three groups according to preceding statin therapy: intensive statins (IS, n=24), moderate statins (MS, n = 26), and no statin (NS, n = 64). The vulnerability of each NCAL was evaluated by density (low-density plaque defined as CT density ≤ 38 HU), positive remodeling (remodeling index > 1.05), and the presence of adjacent spotty calcification.

Percentages of patients in the IS, MS, and NS groups with low-density NCALs were 46%, 58%, and 80%, respectively (p = 0.009) and positive remodeling NCALs were 54%, 58%, and 75%, respectively (p = 0.10). We also found an inverse correlation between serum LDL-C level and the minimum plaque CT density. According to the regression equation, a CT density of 38 HU corresponded with LDL-C of 100 mg/dl. The number of low-density plaques was positively correlated with low-density to high-density lipoprotein cholesterol ratio (LDL-C/HDL-C). An LDL-C/HDL-C > 2.5 independently predicted multiple low-density plaques (OR 2.39 [95%CI: 1.28-4.86], p < 0.001).

Our CTA findings demonstrate that low-density NCALs occur less frequently in patients with intensive statin pre-treatment. A high LDL-C/HDL-C ratio is also associated with larger numbers of low-density NCALs.