While diuretics are sometimes used in atrial septal defect (ASD) treatment, their effect on ASD size reduction remains unclear. We aimed to evaluate the efficacy of diuretics in ASD size reduction in pediatric patients.

We retrospectively reviewed the medical records ofpatients with secundum ASD (size ≥10 mm), between 2005 and 2019. Patients weredivided into two groups based on the diuretic administration.

Of the 73 enrolled patients, 40received diuretics. The initial age at ASD diagnosis (2.8±1.7 vs. 2.5±2.0 years, p=0.526) and follow-up duration (22.3±11.4 vs. 18.7±13.2 months, p=0.224) were not significantly different between the groups. Though not statistically significant, the ASD diameter at the initial diagnosis was larger in the diuretic group (13.7±2.0 vs. 13.5±3.4 mm, p=0.761) and the indexed ASD diameter was larger in the non-diuretic group (25.5±5.9 vs. 26.9±10.3 mm/m²,p=0.493). The ASD diameter significantly increased in the non-diuretic group during follow-up (0.0±2.9 vs. +2.6±2.0 mm, p<0.001). The indexed ASD diameter significantly decreased in the diuretic group during follow-up (−5.7±6.5 vs. +0.2±3.9 mm/m², p<0.001). In the multivariable analysis, diuretic use (odds ratio[OR] 0.120; p=0.001) was the only factor associated with ASD diameter decrease and the most powerful factor in indexed ASD diameter reduction (OR 0.078; p<0.001). Device closure was more frequently performed in the diuretic (75.0%) than in the non-diuretic group (39.4%).

Patients receiving diuretics are less likely to undergo surgery. Diuretics may enable the use of smaller ASD devices for transcatheter treatment through ASD size reduction.