Remnant Lipoproteins Are Residual Risk Factor for Future Cardiovascular Events in Patients With Stable Coronary Artery Disease and On-Statin Low-Density Lipoprotein Cholesterol Levels <70 mg/dL

Background: This study examined the predictive value of remnant lipoprotein levels for cardiovascular events (CVEs) in patients with stable coronary artery disease (CAD) and low-density lipoprotein cholesterol (LDL-C) levels <70 mg/dL on statin treatment. Methods and Results: Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol: RLP-C) were measured by an immunoseparation method in 247 consecutive patients with CAD who had on-statin LDL-C levels <70 mg/dL. All the patients were followed prospectively for a period of <= 60 months or until the occurrence of the primary composite endpoint of cardiac death, nonfatal myocardial infarction, unstable angina requiring coronary revascularization, worsening heart failure, peripheral artery disease, aortic event, and ischemic stroke. During a mean follow-up period of 38 months, 33 CVEs occurred. Kaplan-Meier analysis demonstrated that higher RLP-C levels (>= 3.9 mg/dL, determined by ROC curve) resulted in a significantly higher probability for the primary endpoint than did lower RLP-C levels (<3.9 mg/dL) (P<0.01 by log-rank test). Stepwise multivariate Cox proportional hazard analysis showed that RLP-C was a significant predictor of the primary endpoint after adjustment for known risk factors and lipid variables including triglycerides, and total apolipoprotein B (hazard ratio 1.62, 95% confidence interval 1.26-2.07, P<0.01). Conclusions: RLP-C levels are a residual risk factor for future CVEs in patients with CAD and on-statin LDL-C <70 mg/dL.