Abstract 4365030: Excess Apolipoprotein B Improves Risk Assessment of All-Cause Mortality in Patients with Aortic Stenosis: Insights from the ARISTOTLE Study

Aims: Discordance analyses showed that apolipoprotein B (apoB) is better for assessing cardiovascular disease risk than low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C). However, its additional value beyond LDL-C or non-HDL-C in aortic stenosis (AS) remains underexplored. Methods: Moderate to severe AS patients (n=467) from ARISTOTLE study were included. Excess apoB was defined as the difference between the observed apoB and the expected apoB based on their given LDL-C or non-HDL-C level. Association of excess apoB with the risk of all-cause mortality was assessed by Cox proportional hazards regressions with 95% confidence intervals (CIs). Additionally, the incremental value incorporating excess apoB into standard models for predicting outcome was evaluated. Results: ApoB and LDL-C were highly correlated (r=0.92), with LDL-C account for 84% of the variability in apoB levels. A dose-dependent association was observed between excess apoB based on LDL-C and the risk of all-cause mortality in AS patients. For each one standard deviation (SD) increase in excess apoB, the multivariate-adjusted hazard ratio (HR) for all-cause mortality was 1.021 (95%CI, 1.004-1.038). The multivariable adjusted HR for excess apoB >12.71 mg/dL was 1.998 (95% CI: 1.233-3.237). When excess apoB was added to the standard risk model, the prediction accuracy significantly improved, as indicated by notable changes in the C-statistic, continuous NRI, and IDI (all P-values < 0.05). Similar improvements in prediction were observed when excess apoB was calculated based on non-HDL-C. Conclusions: Excess apoB was dose-dependently associated with an increased risk of all-cause mortality in moderate to severe AS. Key words: excess ApoB, aortic stenosis, all-cause mortality, LDL-C, non-HDL-C