Transseptal vs Transapical Transcatheter Mitral Valve-in-Valve and Valve-in-Ring Implantation: A Systematic Review and Meta-Analysis.

Transcatheter mitral valve replacement has become a useful alternative for patients with failed mitral prosthesis or annuloplasty rings who are deemed high risk for redo surgery. We aimed to compare the clinical outcomes following transseptal (TS) and transapical (TA) approaches in transcatheter mitral valve-in-valve and valve-in-ring implantation (TMViV/R). Electronic databases PubMed, MEDLINE, and Embase were searched through November 2022. Both clinical trials and observational studies comparing patients undergoing TS and TA TMViV/R were eligible for inclusion. Primary outcomes were 30-day and 1-year mortality. Postoperative stroke, left ventricle outlet tract (LVOT) obstruction, mitral valve pressure gradient (MVPG), bleeding, and length of hospital stay were also evaluated. Seven observational studies were included comparing patients undergoing TS (n = 1875) and TA (n = 1120) TMViV/R. The TS group had significantly lower 30-day mortality (OR: 0.66; 95% confidence interval [CI] [0.47, 0.94]; P = 0.02, I² = 0%) and lower one-year mortality risk group (HR: 0.79; 95% CI [0.63, 0.99]; P = 0.04, I² = 0%) compared to the TA group. The TS group had consistent shorter in-hospital stay (MD = -3.79; 95% CI [-5.23, -2.34] days; P < 0.0001, I² = 75%). Postoperative stroke, bleeding and LVOT obstruction tended to be lower in the TS but the results did not reach statistical significance. Postoperative MVPG was similar between both groups. The TS approach has lower early mortality, lower 1-year death hazard, shorter in-hospital stay, and a trend toward lower complication rates when compared to TA TMViV/R. Further controlled trials may support the evidence and provide long-term outcomes.