Outcomes of Iatrogenic Atrial Septal Defect Closure After Transseptal Transcatheter Mitral Valve Replacement in the Mitral Implantation of Transcatheter Valves (MITRAL) Trial

Background

The long-term hemodynamic consequences of iatrogenic atrial septum defect (iASD) after transseptal (TS) transcatheter mitral valve replacement (TMVR) are unknown. The objective of this study was to compare the clinical outcomes of patients who underwent iASD closure after TS TMVR in the MITRAL (Mitral Implantation of TRAnscatheter vaLves) trial.

Methods

The MITRAL trial enrolled high-surgical-risk patients with severe mitral annular calcification treated with valve-in-mitral annular calcification (ViMAC), failed surgical repair with annuloplasty ring treated with mitral valve-in-ring (MViR), or failed surgical mitral bioprosthesis treated with mitral valve-in-valve (MViV).

Results

Ninety-one patients were prospectively enrolled between February 2015 and December 2017, at 13 US sites (MViV ​= ​30, MViR ​= ​30, ViMAC ​= ​31). Seventy-five of them were treated with TS access (MViV ​= ​30, MViR ​= ​30, and ViMAC ​= ​15), of which 16 patients underwent iASD closure during or after the index procedure (MViV ​= ​3, MViR ​= ​7, ViMAC ​= ​6). Closure of the iASDs was left to the operator's discretion, and the reason in most patients was the presence of large left-to-right shunt. Patients who underwent closure of iASD were a sicker population at baseline with more severe symptoms (87.5% with New York Heart Association functional class III-IV, compared to 81.4% in non-iASD closure group, p ​= ​0.02), higher rate of recent heart failure hospitalization (68.8% vs. 30.5%; p ​= ​0.01) and lower 6-minute walk test distance (110 m vs. 214 m; p ​= ​0.002). These patients also had longer length of stay after TMVR compared with patients who did not undergo iASD closure (8 vs. 4 days, p < ​0.001). Despite these differences at baseline and requiring longer hospital stays, there was no significant difference in mortality, New York Heart Association class, 6-minute walk test distance, or heart failure hospitalization at 5 years.

Conclusions

Patients who underwent iASD closure were more symptomatic at baseline, had decreased functional exercise capacity and required longer length of stay after TMVR. Despite these differences at baseline, 5-year outcomes were similar between groups.