Background Dialysis is a rare but serious complication after transcatheter aortic valve replacement. We analyzed the large multicenter TRITAVI (transfusion requirements in transcatheter aortic valve implantation) registry in order to develop and validate a clinical score assessing this risk. Methods and Results A total of 10 071 consecutive patients were enrolled in 19 European centers. Patients were randomly assigned (2:1) to a derivation and validation cohort. Two scores were developed, 1 including only preprocedural variables (TRITAVIpre) and 1 also including procedural variables (TRITAVIpost). In the 6714 patients of the derivation cohort (age 82±6 years, 48% men), preprocedural factors independently associated with dialysis and included in the TRITAVIpre score were male sex, diabetes, prior coronary artery bypass graft, anemia, nonfemoral access, and creatinine clearance