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

ObjectivesThe 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.BackgroundTransseptal 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.Methods80 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.ResultsAll 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).ConclusionsIn 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)