Approach to treatment in the intervention arm based on shunt volume and its clinical effects (SMART protocol)
| Clinical | Echocardiography | Management plan |
| Mild | Mild | Observe |
| Mild | Moderate | Observe |
| Moderate | Mild | Observe |
| Severe | Mild | Observe |
| Moderate | Moderate | Treat |
| Any clinical stage | Severe | Treat |