Abstract 14223: Atrial Fibrillation, Clinical Outcomes, and Post-discharge Natriuretic Peptide Trajectory Among Patients Hospitalized for Heart Failure: Findings From the ASTRONAUT Trial

Introduction: Heart failure (HF) clinical trials have used change in NT-proBNP as a surrogate endpoint, but the influence of atrial fibrillation/ flutter (AFF) on this endpoint is unclear. We investigated the association of AFF with change in NT-proBNP and clinical outcomes following HF hospitalization. Methods: Characteristics and outcomes of 1,358 patients from the ASTRONAUT trial were compared by presence/ absence of AFF on baseline ECG. Patients with history of AFF but without AFF on ECG were excluded. Full factorial repeated measures design using AFF and study randomization was used to predict NT-proBNP changes from baseline to 1, 6, and 12 months. Survival analysis was used to examine the correlation between AFF and outcomes. Results: Patient characteristics and outcomes are displayed in the Table. Among placebo patients, AFF was associated with higher NT-proBNP level at all time points, but larger reductions from baseline levels (p for interaction <0.01). These differences became non-significant after accounting for other clinical characteristics. The ability of aliskiren to lower NT-proBNP over time differed by AFF status (p for interaction <0.01, Figure). After adjustment for patient characteristics, AFF was not associated with cardiovascular mortality/ HF hospitalization or all-cause death at 12 months (all p≥0.15). Conclusions: Absolute levels and change from baseline in NT-proBNP over time differ in HF patients with and without AFF. The ability of a study drug to lower NT-proBNP may depend on the AFF prevalence in the population. AFF was not independently associated with clinical outcomes in this cohort.