Results:

A total of 91 patients underwent TMVI. The median age was 73 (57–81) years, and 70% of patients were women. Patients were at high risk for surgery with a median EuroSCORE II of 9.6 (4.0–14.6)%. The indications for TMVI were bioprosthesis failure (valve-in-valve) in 37.3%, annuloplasty failure (valve-in-ring) in 33.0%, and severe mitral annular calcification (MAC) in 29.7%. A transseptal approach was used in 92.3% of patients, and balloon-expandable valves were used in all patients. Technical success was achieved in 84.6% of patients. One patient died during the procedure and hemodynamically significant left ventricular outflow tract obstruction occurred in three patients (3.3%). At 30 days, 7.7% of patients had died; without significant differences between groups, a major stroke occurred in 2.2% of patients, and 8.8% of patients had valve thrombosis. The cumulative rates of all-cause mortality at 1-year and 2-year follow-up were 21.0% (95% confidence interval [CI], 9.9-38.8) and 35.7% (95% CI, 19.2-56.5), respectively, with a higher late mortality among patients in whom TMVI was seated in severe MAC. The 2-year rates of re-intervention and valve thrombosis were 8.8% and 14.4%, respectively. At 6 months to 1 year, 68.9% of patients were in New York Heart Association class I or II, and 90.7% of patients had mild or less mitral regurgitation. The mean transmitral gradient decreased from 9.3 ± 3.9 mm Hg at baseline to 6.0 ± 2.3 mm Hg at discharge (p < 0.001), without changes at 6-month to 1-year follow-up.