Objectives We examined loop diuretic treatment before and 1-year after transcatheter aortic valve implantation (TAVI), as a proxy for changes in symptom severity and secondly assessed how changes in loop diuretics related to mortality risk. Background Randomized clinical trials suggest that approximately one third of patients undergoing TAVI do not achieve symptom relief, but "all-comer"data are lacking. Methods Using Danish nationwide registries, we identified all citizens, who underwent TAVI from 2008 to 2019 and were alive at 1-year post-discharge. Loop diuretic treatment pre-TAVI and at 1-year post-TAVI were assessed and grouped as receiving 1) no-loop diuretics; 2) low: 1-40 mg of furosemide (or equivalent bumetanide) daily; 3) intermediate: 41-120 mg of furosemide daily; or 4) high: >120 mg furosemide daily. Results Among the 4431 patients undergoing TAVI, 2173 (49%) patients were not treated with loop diuretics at the time of TAVI, 918 (21%) had low-loop diuretics, 881 (20%) had intermediateloop diuretics, and 459 (10%) had high-loop diuretics. At 1-year post-TAVI, 893 (20%) patients had increased, 1010 (23%) had reduced, and 2528 (57%) had unchanged loop diuretic treatment. The cumulative 5-year risk of death in patients surviving one year, was 61% (95% CI: 56.4% to 65.3%) in patients with increased and 47% (95% CI: 44.9% to 49.9%) in patients with reduced/unchanged loop diuretic treatment, respectively. In multivariable Cox proportional hazard analysis, increased loop diuretic treatment was associated with a higher risk of death compared with reduced/unchanged loop diuretic treatment (Hazard ratio: 1.4; 95% CI: 1.22 to 1.52). Conclusions Among patients undergoing TAVI, surviving one year, one fifth of patients had increased loop diuretic treatment, and a little over one fifth had reduced loop diuretic treatment 1-year post-procedure. In patients with increased diuretic treatment, the risk of death was higher compared to those with reduced/unchanged loop diuretic treatment.