Management and Closure Strategies for Atrial Septal Defect with Bidirectional Shunt and Pulmonary Arterial Hypertension: A Comprehensive Review of the Paradigm Shift Toward Reverse Remodelling

Abstract

Atrial septal defect (ASD) complicated by severe pulmonary arterial hypertension (PAH) and bidirectional shunting represents a critical clinical challenge in adult congenital heart disease. Traditionally, these patients were often deemed inoperable due to the perceived irreversibility of pulmonary vascular disease and the high risk of acute right heart failure following defect closure. However, recent advances in pharmacological therapy and interventional techniques have catalysed a significant paradigm shift from "Treat and Repair" to "Repair and Treat," emphasizing the biological potential for reverse remodelling of the pulmonary vasculature. This comprehensive review examines the physiological mechanisms of reverse remodelling, diagnostic challenges including invasive hemodynamic assessment, and the strategic use of fenestrated closure devices. By synthesizing contemporary clinical data and longitudinal outcomes, we provide a robust framework for optimizing survival and functional outcomes in this high-risk population.