Moderate aortic stenosis (AS) in patients with heart failure (HF) is associated with a significantly worse prognosis compared to those without AS. This study analyzed 332 patients with elevated brain natriuretic peptide (BNP) levels, finding that those with moderate AS had higher rates of all-cause hospitalization and mortality. The primary outcome was a composite endpoint of all-cause hospitalizations and mortality, with moderate AS showing a hazard ratio (HR) of 1.50 (95% CI, 1.14–1.97) in univariate analysis and 1.45 (95% CI, 1.05–2.01) in adjusted analysis. Moderate AS was also significantly associated with higher hospitalization rates in both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). These findings suggest that moderate AS in the presence of elevated BNP levels warrants close monitoring. The study highlights the need for further research into the role of transcatheter aortic valve replacement (TAVR) in patients with moderate AS and HF. The study's limitations include its retrospective nature and single-center design, which may affect generalizability. Overall, the presence of moderate AS with evidence of elevated filling pressures indicates a worse prognosis and requires urgent attention in clinical practice.Moderate aortic stenosis (AS) in patients with heart failure (HF) is associated with a significantly worse prognosis compared to those without AS. This study analyzed 332 patients with elevated brain natriuretic peptide (BNP) levels, finding that those with moderate AS had higher rates of all-cause hospitalization and mortality. The primary outcome was a composite endpoint of all-cause hospitalizations and mortality, with moderate AS showing a hazard ratio (HR) of 1.50 (95% CI, 1.14–1.97) in univariate analysis and 1.45 (95% CI, 1.05–2.01) in adjusted analysis. Moderate AS was also significantly associated with higher hospitalization rates in both heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). These findings suggest that moderate AS in the presence of elevated BNP levels warrants close monitoring. The study highlights the need for further research into the role of transcatheter aortic valve replacement (TAVR) in patients with moderate AS and HF. The study's limitations include its retrospective nature and single-center design, which may affect generalizability. Overall, the presence of moderate AS with evidence of elevated filling pressures indicates a worse prognosis and requires urgent attention in clinical practice.