Background: The lipid component of coronary plaques is associated with their vulnerability. The aim of this study was to investigate which coronary risk factors were relevant in predicting serial changes in the lipid component of coronary plaques as evaluated by integrated backscatter intravascular ultrasound (IB-IVUS).Methods and Results:We enrolled 104 patients who underwent IB-IVUS-guided percutaneous coronary intervention (PCI) and were followed up with repeat IB-IVUS 6 months later. We investigated the serial changes in the plasma lipoprotein levels and the percentage of the lipid component of coronary plaques on IB-IVUS. In the multivariate linear regression analysis, the low-density lipoprotein-cholesterol/high-density lipoprotein-cholesterol (L/H) ratio independently had a significant fixed effect with the percentage of the lipid component of coronary plaques at the time of PCI. In addition, the change in the L/H ratio at the 6-month follow-up was significantly associated with that in the lipid component of coronary plaques (regression coefficient, 9.645; 95% CI: 5.814-13.475; P<0.0001); furthermore, this change was also observed in patients with an LDL-C <100 mg/dL.
Conclusions: The L/H ratio was the most relevant parameter in predicting the lipid component of coronary plaques. Furthermore, strict management of the L/H ratio may reduce this lipid component, even in patients with an LDL-C <100 mg/dL.
Keywords: Hypercholesterolemia; Intravascular ultrasound; Lipoproteins; Vulnerable plaque.