Philips IEElite advanced cardiac color Doppler ultrasound and Philips IE33 advanced cardiac color Doppler ultrasound systems were used for VSD diagnosis. The frequency of the probe was 3-5 MHz, and they could display the location, size, and the base, width, depth of the perimembranous aneurysm, and the width of the breach in multiple sections, angles, and directions. If there were multiple breaches, it was calculated by the sum of all breach widths
Determination of inflammatory factors in aneurysmal perimembranous tissue: aneurysmal perimembranous tissue with a size of 3 mm × 3 mm was taken from the breaches from all children with APVSD during the operation. The tissue was minced and ground sufficiently, and the suspension was collected by centrifugation. The levels of IL-1β, IL-6, TGF-β, and TNF-α were determined by ELISA.