Apolipoprotein B48 as a Marker of Residual Coronary Risk: Diagnostic Insights from a Comparative Analysis with Ankle-Brachial Index.

Apolipoprotein B48 (ApoB48) may be an indicator of residual cardiovascular risk beyond conventional lipid measures. However, its performance for detecting coronary artery disease (CAD), alone and in combination with the ankle-brachial index (ABI), remains to be investigated. This cross-sectional study (358 patients; 299 and 59 with and without CAD, respectively) assessed the value of ApoB48 (cutoff: ≥4.5 μg/mL) and ABI (cutoff: <0.9) in detecting CAD. Subgroup analyses were performed for patients with diabetes mellitus, hypertension, dyslipidemia, and low levels of low-density lipoprotein-cholesterol (LDL-C) (<100 mg/dL). Baseline characteristics, including lipid profiles and biomarker levels, were compared between patients with and without CAD. Patients with CAD exhibited significantly higher ApoB48 levels compared to those without (5.1 ± 3.2 vs. 4.0 ± 2.2 μg/mL, respectively, p = 0.001); there were no significant differences in ABI values. The sensitivity and specificity of ABI alone for CAD were 16.7% and 81.4%, respectively, while those for ApoB48 alone were 48.2% and 61.0%, respectively. Combining both markers improved sensitivity to 55.5%, though specificity declined to 47.5%. Subgroup analyses revealed that ApoB48 maintained superior sensitivity across groups with diabetes, hypertension, dyslipidemia, and low levels of LDL-C. Lipid parameters (LDL-C, non-high density lipoprotein-cholesterol, and triglycerides) showed minimal discriminatory power between patients with and without CAD. ApoB48 demonstrates superior sensitivity for CAD detection compared to ABI, particularly in high-risk patients. While combining ApoB48 and ABI enhances sensitivity, it compromises specificity, suggesting the need for balanced diagnostic strategies. ApoB48 may be a valuable marker of residual cardiovascular risk, particularly in patients with well-controlled LDL-C or comorbid metabolic conditions.