Perimembranous VSDs do not frequently close on their own, particularly if they are moderate to large in size. ASDs can get smaller, and even close. If the ASD is only 5mm at 5 months of age, it is possible it will close, or at least not require surgery (or even catheter based closure). The VSD is more difficult to predict. If the child continues to do well clinically, doesn’t require any medical therapy, is growing and thriving, he can wait. We do watch the aortic valve closely because flow through the defect can influence that valve and cause problems. If it does, surgery will be necessary. Sometimes the defect can be partially closed by valve tissue from the tricuspid valve (from the right ventricle). If that happens (or has already happened), sometimes we can close those defects in the catheterization laboratory, without surgery.
The short answer is the ASD may not need anything or could be closed with a device and without surgery. The VSD is more difficult to predict and hard for me to comment without more information. However, if he is doing well, there is time and surgery may not be necessary.
Thank you for this question.
Dr, John Breinholt