Usefulness of Follow-Up Low-Density Lipoprotein Cholesterol Level as an Independent Predictor of Changes of Coronary Atherosclerotic Plaque Size as Determined by Intravascular Ultrasound Analysis After Statin (Atorvastatin or Simvastatin) Therapy

Using serial intravascular ultrasound (IVUS), we identified independent predictors of changes in coronary plaque size in relation to serum lipid levels. One hundred three patients with nonstenotic coronary plaques underwent baseline and 12-month follow-up IVUS studies; 54 patients (52%) were treated with statins. Standard IVUS analyses were performed. Baseline IVUS study showed no statistical differences in mean external elastic membrane, lumen, and plaque/media (P&M) area between statin-treated and nonstatin-treated patients. Although there was an increase in mean P&M cross-sectional area in nonstatin-treated patients, mean P&M cross-sectional area decreased in statin-treated patients (0.11 ± 0.24 vs −0.20 ± 0.30 mm2, p <0.001). There was a positive relation between changes in mean P&M area and follow-up low-density lipoprotein (LDL) cholesterol level (r = 0.430, p <0.001), follow-up total cholesterol level (r = 0.365, p <0.001), changes in LDL cholesterol level (r = 0.312, p = 0.002), and changes in total cholesterol level (r = 0.252, p = 0.012). In multivariate linear regression analysis, the only independent predictor of changes in mean P&M area was follow-up LDL cholesterol level (r = 0.469, p <0.001, 95% confidence interval 0.003 to 0.006). The cut-off value of follow-up LDL cholesterol for no change or a decrease in mean P&M area was <100 mg/dl at regression analysis. In conclusion, the present 12-month follow-up IVUS study showed that follow-up LDL cholesterol level was the only independent predictor of changes in coronary plaque size. When patients achieved a follow-up LDL cholesterol level <100 mg/dl, regression or no progression of coronary plaque was expected. Aggressive lipid-lowering treatments with statins to decrease the follow-up LDL cholesterol level to <100 mg/dl are recommended.