Evolution of Untreated Moderate Mitral Regurgitation After Transcatheter Aortic Valve Implantation.

: Associated mitral regurgitation (MR) is frequently observed during transcatheter aortic valve implantation (TAVI). The progression of moderate MR remains undetermined, given uncertain clinical significance and natural history. This study aims to assess the evolution of moderate MR following TAVI. : Between 2018 and 2023, 1476 patients underwent TAVI. We excluded those with previous aortic or mitral valve interventions, endocarditis, concomitant percutaneous coronary intervention, or emergent procedures. Patients with severe aortic or tricuspid regurgitation or significant mitral stenosis were excluded. Ultimately, only patients with moderate MR were included, resulting in a final population of 154 patients. : Mean age was 81.4 ± 7.8 years, 48.1% (74/154) were female, and 48.1% (74/154) were functional MR. There was one surgical conversion due to annular rupture. Thirty-day mortality was 1.9% (3/154). Postoperative echocardiography showed 38 (24.7%) patients with none/trace MR, 91 (59.1%) with mild MR, 22 (14.3%) with moderate MR, and 3 (1.9%) with severe MR. Finally, according to the echocardiographic follow-up [median follow-up 1.0 (IQR: 0.1-1.2) years], 20.1% (31/154) had no/trace MR, 39.6% (61/154) had mild MR, 35.7% (55/154) had moderate MR, and 4.5% (7/154) had severe MR. Overall, 67 (43.5%) patients had any MR grade progression, 62 (40.3%) had stable disease, and 25 (16.2%) had any MR grade reduction at the last follow-up from the operation. No difference in MR evolution was seen between functional and primary MR. : Concomitant moderate MR during TAVI has a variable evolution over time. A more detailed characterization of patients with preoperative moderate MR undergoing TAVI is necessary to identify those with a disease progression risk.