Federica Serra

Background. Transaortic flow rate (FR) has been proposed as a flow-derived echocardiographic marker for risk stratification in severe aortic stenosis (AS). Its prognostic value in patients undergoing transcatheter aortic valve implantation (TAVI) and the influence of cardiac rhythm remain uncertain.Objectives. To assess the association between FR and all-cause mortality after TAVI and determine whether the association is modified by cardiac rhythm. Stroke volume index (SVi) was evaluated as a secondary parameter.Methods. We retrospectively studied 1,008 patients undergoing TAVI for severe AS. FR was analyzed per 50 mL/s increase and using a threshold of 210 mL/s. SVi was analyzed per 10 mL/m² increase and using a threshold of 35 mL/m². Associations with all-cause mortality were evaluated using Cox regression, including interaction terms between cardiac rhythm and FR or SVi in multivariable models.Results. Of 1,008 patients, 837 (83%) were in sinus rhythm (SR) and 171 (17%) had atrial fibrillation (AF). During a median follow-up of 29.7 months, higher FR was associated with lower mortality in SR (HR 0.853, 95% CI 0.745-0.977; p=0.021) but not in AF (HR 1.052, 95% CI 0.830-1.334; p=0.674). Similar findings were observed for SVi. No significant interaction was found between cardiac rhythm and FR (p=0.254) or SVi (p=0.415).Conclusions. Higher FR was associated with improved survival in SR but not in AF after TAVI. Cardiac rhythm did not modify the association between FR and mortality. Flow-derived parameters may be influenced by rhythm-related hemodynamic variability. Larger studies are needed to clarify their role in AF.