When apolipoprotein B speaks: early clues to coronary disease burden

Introduction Apolipoprotein B (ApoB) is a key marker of atherogenic lipoproteins and a strong predictor of cardiovascular risk. Recent data suggest that, although seldom measured in clinical practice, it outperforms low-density lipoprotein cholesterol in predicting atherosclerotic cardiovascular disease risk. Purpose The objective of our study is to assess whether baseline ApoB levels can predict cardiovascular disease severity in patients enrolled in a cardiac rehabilitation program. Methods This was a prospective observational single-center study including patients with ischemic coronary artery disease enrolled in a phase II cardiac rehabilitation program between 2023 and 2025. Patients were stratified into two groups based on baseline ApoB levels (≥80 mg/dL or <80 mg/dL). Clinical, echocardiographic, and cardiopulmonary exercise test (CPET), data were collected. A composite outcome of all-cause mortality, cardiovascular hospitalizations, and reinfarction was evaluated. Results A total of 151 patients (88% male; 61.1 ± 10.4 years) with ischemic cardiomyopathy enrolled in the phase II cardiac rehabilitation program. Common comorbidities included hypertension (63.3%), dyslipidemia (72.2%), smoking (31.1% current; 32.5% former), and diabetes (28.7%). At admission, mean ApoB levels were 71.68 ± 23.16 mg/dL, and 46 patients had levels of at least 80mg/dL. Patients with ApoB ≥80 mg/dL were younger at the start of cardiac rehabilitation (58.3 years [95% CI 55.2–61.5] vs 62.3 years [95% CI 60.3–64.3], p=0.031), and, were, therefore, younger at the time of the coronary event. ApoB levels of at least 80mg/dL were also associated with the severity of coronary artery disease. In fact, patients with higher levels of ApoB had twice the odds of having multivessel disease (OR 2.11 [CI 95% 1.03-4.32], p 0.039) and four times the odds of being submitted to coronary artery bypass grafting surgery (OR 4.28 [CI 95% 1.82-10.07], p <0.001). Other clinical variables including weight, body mass index, NYHA class, HbA1c, glomerular filtration rate and NT-proBNP levels, 6 minute walk test and CPET parameters were similar between both groups. During a mean follow-up of 1.28 ± 1.61 years, no statistically significant difference was found between the two groups regarding the composite outcome of all-cause mortality, cardiovascular hospitalizations, and reinfarction, with only three events in each group (p=0.474). Conclusion In our cohort, patients with ApoB ≥80 mg/dL were younger and had more severe ischemic coronary artery disease, underscoring the value of ApoB as a marker of cardiovascular risk and disease burden. These findings support the broader incorporation of ApoB measurement into routine clinical practice for risk stratification and early identification of high-risk patients.