How do you decide when to operate for a small supracrystal vsd?

Need echocardiogram!: A supracristal vsd is quite uncommon, making up only about 3% of all ventricular septal defects. A small defect may not cause any signs of congestive heart failure. The decision to surgically close rests on any interference of the function of the aortic valve by the shunting of blood through the hole. This can cause damage to the valve leaflets, and leakage of the valve itself.

Depends: On the amount of blood crossing from left heart to the right heart through the defect. This can be assessed with an echocardiogram. If closure us needed it will show an enlarged left heart.