Abstract Background In Aortic stenosis (AS) cardiovascular comorbidities as well as left ventricular ejection fraction (LVEF) have an impact on postoperative outcome among patients undergoing aortic valve replacement (AVR). The prevalence of heart failure (HF) based on LVEF in patients with severe AS varies. Lately HF with preserved LVEF has gained more attention. The aim is to describe the prevalence and prognostic impact of cardiovascular comorbidities, including HF, in relation to LVEF before AVR in a national cohort of patients with AS. Methods Patients >18 years, undergoing AVR due to AS 2008–2014 were identified in the national register for heart diseases, SWEDEHEART. Preoperative LVEF and comorbidities were collected from the register and enriched with data from national patient registries. The outcome events were all cause mortality and hospitalization for HF as the main diagnosis. The cohort was separated by preoperative LVEF status; preserved (>50%) or reduced (≤50%). Outcome events were analysed by Cox regression. Results 10406 patients, median age 73 (18–96) years whereof 3817 (36.7%) women, were included with a median follow-up of 35 months. In the cohort 15.9%, 73.9% and 10.2% received a mechanical, surgical biological and trans-catheter biological valve prosthesis, respectively. Preserved LVEF was present in 7512 (72.2%). Comorbidities were more frequent in the group with reduced LVEF (p<0.001). Irrespective of LVEF HF influenced outcome negatively (see table). Conclusion In patients planned for AVR a history of HF irrespective of LVEF worsen postoperative prognosis and a history of HF seems at least as important as LVEF when predicting long-term outcome. When stratifying patients for AVR with preserved LVEF, comorbidities such as HF and atrial fibrillation should be highlighted, and further research to identify risk factors for a negative postoperative outcome in this group seems important in optimizing the follow-up after AVR. Funding Acknowledgement Type of funding source: None