Abstract Background Symptomatic severe aortic stenosis (AS) requires surgical (SAVR) or transcatheter aortic valve replacement (TAVR), and many patients are on the procedure waiting list. The diagnosis of severe AS is based on clinical and echocardiographic criteria, such as left ventricular ejection fraction (LVEF), aortic valve area (AVA), mean transvalvular gradient, and peak aortic jet velocity. However, there is a gap in knowledge regarding the influence of left ventricular mass on the prognosis of these patients, especially considering differences between women and men. Purpose To evaluate the influence of left ventricular mass index (LVMi) on the mortality of women and men with severe AS awaiting SAVR or TAVR. Methods A prospective study analysed the death rate in 531 outpatients with symptomatic severe AS with mean transvalvular gradient ≥40 mmHg, AVA ≤1.0 cm2, or peak aortic jet velocity ≥4.0m/s at echocardiography with the indication for TAVR or SAVR in the period from April 2020 to February 2024. Baseline data included analysis of clinical characteristics, echocardiographic variables, and the presence of coronary artery disease (CAD). Statistical analyses were performed using the Kaplan-Meier (K-M) and Cox proportional hazards methods to analyze mortality rates in women and men. Results The mean age was 74.7±11.6 years, with 283 (53.3%) men. Over a follow-up period of 2.67±1.22 years, death occurred in 165 (31.1%), 148 (86%) due to cardiovascular disease, and 152 (92%) had heart failure (HF) NYHA II to IV, 51 (9,6%) had angina, and syncope in 11 (2.1%) of the patients. Patients who died had lower LVEF (61.4%±8.9% vs. 58.8%±10.8%; p=0.008) and higher LVMi (125.3±32.5 g/m2 vs. 115.5±29.3 g/m2; p=0.001). Angina, syncope, hypertension, dyslipidemia, diabetes, smoking, atrial fibrillation, and CAD prevalence were similar in living patients and in those who died. Both groups had similar echocardiographic data, such as left atrial volume, mean transvalvular gradient, and peak jet velocity. TAVR and SAVR were done in 111 (20.9%) and 162 (30.5%) patients. Of these, 21 (18.9%) and 20 (12.4%) died during follow-up, respectively. Cumulative mortality of all patients was higher with LVMi >115 g/m2 compared to ≤115 g/m2 (p=0.008)(Figure). In women but not in men, cumulative mortality was higher with LVMi >115 g/m2 compared to ≤115 g/m2 (p=0.046). Cox multivariate analysis, adjusted for LVEF, LVMi, CAD, and age, showed LVMi as an independent variable for death [HR=1.50 (95%CI: 1.10-2.05); p=0.011]. LVEF [HR=0.97 (95%CI: 0.95-0.99); p=0.009] and LVMi [HR=1.75 (95%CI: 1.10-2.79); p=0.016] were independent variables for death in women, but not in men. Conclusion Women with higher LVMi and lower LVEF should have valve intervention prioritized.Figure