BACKGROUND: Transcatheter aortic valve implantation (TAVI) is increasingly performed in younger and lower-risk patients. Since many of these patients will outlive their transcatheter heart valve (THV), redo-TAVI procedures are expected to rise in number. Yet, real-world evidence on the procedural safety and efficacy of redo-TAVI remains limited. AIMS: We aimed to evaluate the 30-day procedural and clinical outcomes of redo-TAVI using the balloon-expandable SAPIEN 3 platform. METHODS: The ReTAVI registry is a prospective, international study enrolling consecutive patients with a failed aortic THV undergoing redo-TAVI with a balloon-expandable SAPIEN 3 THV. Data were collected across 59 international centres. All imaging was centrally analysed, and major clinical events were adjudicated by an independent committee. RESULTS: â¨A total of 143 patients (median age 84 years; 40.6% female; median Society of Thoracic Surgeons risk score 7.0%) were enrolled. The predominant failing THVs were balloon-expandable SAPIEN 3 (30.1%), self-expanding CoreValve/Evolut (53.1%), and ACURATE (14.0%) platforms. The most common failure mode was isolated regurgitation (48.6%), followed by stenosis (35.2%) and a mixed pathology (16.2%). The replacement valve was successfully implanted in 95.1% of patients, with a 30-day mortality rate of 3.5%. The 30-day stroke and pacemaker implantation rates were 0.7% and 6.3%, respectively. Redo-TAVI significantly improved valve haemodynamics, with mean gradients decreasing overall (Δ=-12.0 mmHg), and a more pronounced reduction in stenotic failures (Δ=-29.0 mmHg). Coronary obstruction was observed in 1.4% of cases. CONCLUSIONS: Redo-TAVI with a balloon-expandable SAPIEN 3 THV platform is a safe and effective reintervention strategy across diverse failed THV types, when guided by the Heart Team, standardised procedural planning, and comprehensive imaging. CLINICALTRIALS: gov: NCT05601453.