[Clinical analysis and follow-up study of transcatheter closure of secundum atrial septal defect in infants].

<b>Objective:</b> To evaluate the clinical characteristics and prognosis of transcatheter closure of secundum atrial septal defect (ASD) in infants. <b>Methods:</b> A retrospective analysis was conducted on 83 cases with secundum ASD who underwent transcatheter closure at the Women and Children's Hospital of Qingdao University from January 2010 to December 2021. The clinical data included general information, pre- and post-operative echocardiography and electrocardiography, surgery records, and follow-up outcomes. The children who underwent successful occlusion were divided into two groups based on the presence or absence of pulmonary hypertension: the normal group and the pulmonary hypertension group. Differences between the two groups in terms of age, weight, right ventricular end-diastolic diameter, maximum ASD diameter, occluder size, and pulmonary-to-systemic flow ratio (Qp/Qs) were compared. Intergroup comparisons were performed using the Wilcoxon test. <b>Results:</b> Among the 83 infants with secundum ASD, 12 were males and 71 were females, with the age of (10.8±1.6) months. There were 29 cases (35%) with weight-for-age below the median level (less than the 25th percentile), 19 cases (23%) with recurrent or refractory pulmonary infections, and 40 cases (48%) with pulmonary hypertension. In this study, 81 cases (97%) successfully completed the procedure, while 2 cases failed due to soft defect margins. Postoperative arrhythmias occurred in 12 cases, of which 11 were transient arrhythmia; one case of atrioventricular block returned to normal rhythm after surgical removal of the occluder. The 81 infants who underwent successful occlusion were divided into normal group (41 cases) and pulmonary hypertension group (40 cases). The pulmonary artery systolic pressure, maximum diameter of ASD, the size of the occluder, and the cardiothoracic ratio were higher in the pulmonary hypertension group compared to those in the normal group, while the Qp/Qs value was lower (all <i>P</i><0.05). Follow-up results indicated that infants with ASD who underwent transcatheter closure had no new arrhythmias, residual shunts, or intervention-related mortality. Within one year postoperatively, all infants exhibited normalization of right ventricular dimensions and pulmonary artery pressure. During a 3-year follow-up, all 29 cases that originally had a weight-for-age below the median level exhibited catch-up growth, reaching above the median level. <b>Conclusions:</b> Transcatheter closure for secundum ASD in infants is safe and feasible. Follow-up indicates that early transcatheter closure may be necessary for larger ASD diameters combined with pulmonary hypertension, with significant clinical improvement postoperatively.