Iatrogenic Atrial Septal Defects Following Transcatheter Mitral Valve Repair and Implications of Interventional Closure

Objectives: The authors investigated whether iatrogenic atrial septal defect (iASD) closure post-transcatheter mitral valve edge-to-edge repair (TMVR) is superior to conservative therapy (CT) and whether outcomes (death/heart failure [HF] hospitalization) differ between patients with and without an iASD post-TMVR.

Background: Transseptal access for TMVR can create an iASD, which is associated with impaired outcomes. Controversially, the creation of an iASD in HF has been linked to improved hemodynamics.

Methods: 80 patients with an iASD and relevant left-to-right shunting (Qp:Qs ≥1.3) 30 days following TMVR were randomized to CT or interventional closure of the iASD (MITHRAS [Closure of Iatrogenic Atrial Septal Defect Following Transcatheter Mitral Valve Repair] cohort), and 235 patients without an iASD served as a comparative cohort.

Results: All patients of the MITHRAS cohort (mean age 77 ± 9 years, 39% women) received their allocated treatment, and follow-up was completed for all MITHRAS and comparative cohort (mean age 77 ± 8 years, 47% women) patients. Twelve months post-TMVR, there was no significant difference in the combined endpoint of death or HF hospitalization within the MITHRAS cohort (iASD closure: 35% vs CT 50%; P = 0.26). The combined endpoint was more frequent among patients within the MITHRAS cohort as opposed to the comparative cohort (43% vs 17%; P < 0.0001), primarily driven by a higher rate of HF hospitalization (34% vs 8%; P = 0.004).

Conclusions: In this randomized controlled trial, interventional closure of a relevant iASD 1 month after TMVR did not result in improved clinical outcomes at 12 months post-TMVR. Patients with an iASD are at higher risk for HF hospitalization independent of iASD management and warrant close follow-up. (Closure of Iatrogenic Atrial Septal Defect Following Transcatheter Mitral Valve Repair [MITHRAS]; NCT03024268).