first of all its clear that hole has to be repaired either by device or operation. 11mm is a small size, its better if device closure can be done.
get a transesophageal echo(TEE) done at a very good centre by an experienced operator, three rims are important- IVC rim, SUPERIOR Rim, AV rim. Rest rims are not important, still device closure can be dine.
Next Steps
get a good TEE done.