Atrial septal defect is a common CHD, and transcatheter closure is now the gold standard treatment. In an atrial septal defect, left-to-right shunting increases pulmonary blood flow. This study aimed to evaluate early changes in pulmonary artery, pulmonary vein, and inferior vena cava flow parameters following transcatheter closure of an atrial septal defect.

This retrospective study included 31 paediatric patients with haemodynamically significant atrial septal defect (Qp/Qs ≥ 1.5) who underwent transcatheter closure between January 2023 and June 2024. Comprehensive echocardiography was performed 24 hours before and after the procedure. Pulmonary artery and pulmonary vein maximum and mean pressure gradients, velocities, velocity–time integrals, inferior vena cava maximum and minimum diameters, and the inferior vena cava collapsibility index were analysed at both time points using standard transthoracic echocardiographic techniques.

When the data obtained were evaluated, it was observed that pulmonary artery maximum-mean pressure gradient (p < 0.001), pulmonary artery maximum-mean velocity (p < 0.001), pulmonary artery velocity–time integral (p < 0.001), pulmonary vein maximum pressure gradient (p < 0.001), pulmonary vein mean pressure gradient (p < 0.05), inferior vena cava maximum and minimum diameters (p < 0.001) and inferior vena cava collapsibility index (p < 0.05) decreased statistically significantly after transcatheter closure compared to before.

The duration of remodelling in both the right and left atrial structures following transcatheter atrial septal defect closure depends on the extent of early changes in flow parameters. Our findings suggest that the inferior vena cava collapsibility index may serve as a simple, non-invasive indicator for closure criteria in future studies.