Identifying a Favorable Morphological Profile for Transcatheter Atrial Septal Defect Closure in Patients With Deficient Posteroinferior Rims

BACKGROUND: Transcatheter closure of secundum atrial septal defects (ASDs) with a deficient posteroinferior (PI) rim is challenging owing to an increased risk of technical failure. AIMS: This study aimed to explore morphological characteristics associated with a low-risk profile for procedural success in borderline candidates with PI rim deficiency. METHODS: In this retrospective study, we analyzed 34 patients with PI rim deficiency who underwent transcatheter closure attempts, excluding those initially triaged to surgery. Cut-off values for echocardiographic indices, including the defect-to-septal ratio (DSR) and the defect-to-left atrial volume ratio (DLAR), were determined using receiver operating characteristic (ROC) analysis. The diagnostic performance of single versus combined indices was evaluated. RESULTS: Procedural success was achieved in 29 patients (85%), and technical failure occurred in 5 (15%). Combining DSR and DLAR significantly improved risk stratification compared to DSR alone. Exploratory cut-offs for predicting technical failure were DSR ≥ 61.9% and DLAR ≥ 1.3 mm/mL. Fulfilling at least one low-risk criterion (DSR < 61.9% or DLAR < 1.3 mm/mL) effectively identified a highly favorable cohort, yielding a 100% (23/23) procedural success rate and improving overall diagnostic accuracy to 82%. CONCLUSIONS: Assessing spatial mismatch between the defect and left atrium provides a practical framework for risk stratification in PI rim deficiency. While combined DSR and DLAR criteria identify a potential low-risk profile, these exploratory cut-offs remain hypothesis-generating. This demanding procedure requires extreme caution and meticulous patient selection.