Can an ultrasound replace a catheter for Kids' heart surgery planning?

This study looks at 115 children aged 6 months to 5 years who have a hole in the heart (VSD) and need surgery. Doctors want to see if an ultrasound probe placed in the food pipe (TEE) can measure heart pressure as accurately as the standard method using a thin tube (catheter) inserted into the heart. If TEE works well, it could reduce the need for more invasive procedures.