INTRODUCTION: Aortic stenosis (AS) is the most common valvular disease that affects 3% of the world's population over the age of 65 years and is one of the most significant valvular diseases in developed countries (1). Since the drugs still produce poor results in the treatment of AS (2) replacement of aortic valve is the most important step in the treatment of sympto-matic patients (3). RESEARCH OBJECTIVE: to assess the functional status of patients after administration of TAVI according to the NYHA classification, then investigate the influence of sex and age on the outcome of the procedure and the influence of procedure on echocardiography parameter (EF). METHODS: The study was retrospectively and was conducted on 67 patients who were hos-pitalized at the Hospital Rijeka in the period from 01.01.2016. to 01.01.2020, due to severe aortic stenosis for which the cardiology team assessed the need for TAVI procedure. In the study, the functional status of patients was processed using the functional status assessment scale- NYHA classification and echocardiographic finding before and after TAVI, and the influence of age and gender on the outcome of the procedure by analysing hospital documen-tation, through IBIS. RESULTS: out of the total number of patients 67 (100%), 35 women (52%) participated and 32 males (48%), mean men 77.9 ± 7.6 years and 80.57 ± 4.43 years for women. Subjects had a NYHA classification level of 3-4 prior to the procedure, while after the procedure, NYHA class level was 1. Subjects prior to the procedure, the median EF is 50%, and the same is the median EF of subjects after the procedure. The data was processed using descriptive and infe-rencing statistics. CONCLUSION: by testing the hypothesis in this study, it has come to the conclusion that patients with severe AS, after administration of the TAVI procedure, have improved functio-nal status according to the NYHA classification, that age and gender do not affect the outco-me of the procedure and that patients have the same degree of EF as before the procedure. This study, in addition to researching the positive effect of TAVI surgery on patients with severe AS, also presents the irreplaceable role of the nurse in the overall process.