CT based Annular Dimensions in Transcatheter Mitral Valve Replacement: A Multicenter Registry Study.

Background Transcatheter mitral valve replacement (TMVR) is a preferred interventional option for high-risk patients with severe mitral regurgitation who are ineligible for transcatheter edge-to-edge repair. However, the role of annular dimensions in risk stratification has been marginally explored in this distinct anatomical setting with preserved native leaflets in patients with varying degree of myocardial damage.Methods This subanalysis of the multicenter TENDER registry (NCT04898335) included 145 TMVR patients. Preprocedural 4D-CT-derived annular dimensions were evaluated for associations with cardiac and all-cause mortality.Results At one year, all-cause mortality was 24.8% (n=36/145) and cardiac mortality was 5.5% (n=8/145). Cardiac deaths were associated with significantly larger annular parameters, including systolic and diastolic anteroposterior diameter (32.8±2.3 mm vs. 29.9±3.5 mm, p = 0.023; 33.2±2.5 mm vs. 30.3±3.4 mm, p = 0.018), systolic and diastolic annular perimeter (126.1±9.5 mm vs. 115.8±10.5 mm, p = 0.008; 125.6±10.4 mm vs. 115.8±12.7 mm, p = 0.034), and annular area (1271.7±193.2 mm2 vs. 1076.2±193.6 mm2, p = 0.006; 1262.7±209.9 mm2 vs. 1087.2±194.7 mm2, p = 0.015). Annular Area Loss, calculated as the difference between native diastolic mitral annular area and the geometric EOA of the implanted valve, was significantly greater in patients who died for cardiac reasons (999.72±225.72 mm2) compared to survivors (826.68±189.45 mm2; p = 0.022; OR=1.005, p = 0.030).Conclusions Larger annular dimensions and greater Annular Area Loss may predict one-year cardiac death. Possible mechanisms include impaired LV filling, artificial inflow-related outflow tract obstruction, and limited reverse remodeling. Comprehensive annular assessment may also enhance patient selection for future transseptal TMVR systems.