Clinical classification of congenital, systemic-to-pulmonary shunts associated with pulmonary arterial hypertension (PAH)
| A. Eisenmenger's syndrome |
| Eisenmenger's syndrome includes all systemic-to-pulmonary shunts due to large defects leading to a severe increase in PVR and resulting in a reversed (pulmonary-to-systemic) or bidirectional shunt. Cyanosis, erythrocytosis and multiple organ involvement are present. |
| B. PAH associated with systemic-to-pulmonary shunts |
| In these patients with moderate-to-large defects, the increase in PVR is mild to moderate, systemic-to-pulmonary shunt is still largely present, and no cyanosis is present at rest. |
| C. PAH with small# defects |
| In cases with small defects (usually ventricular septal defects <1 cm and atrial septal defects <2 cm of effective diameter assessed by echocardiography) the clinical picture is very similar to idiopathic PAH. |
| D. PAH after corrective cardiac surgery |
| In these cases, congenital heart disease has been corrected but PAH is either still present immediately after surgery or has recurred several months or years after surgery in the absence of significant post-operative residual congenital lesions or defects that originate as a sequela to previous surgery. |
PVR: pulmonary vascular resistance. #: the size applies to adult patients.