**4. Current status of Fontan operation**

As reviewed above, since the original description in the early 1970s, the Fontan procedure has undergone numerous modifications, and, at the present time it is best described as staged total cavopulmonary connection (TCPC) with an extra-cardiac conduit and fenestration. It is performed in three stages.

## **4.1 Stage I**

The majority, if not all, of patients who require Fontan operation (see Section 3. Indications for Fontan Operation) present during the neonatal and early infancy period, and the Fontan cannot be performed at that time because of naturally high PA pressure and high pulmonary vascular resistance (PVR). Therefore, Fontan, by necessity, becomes a multistage procedure. These babies should receive palliative intervention to allow them to reach the age and size to undergo successful Fontan surgery. The type of palliation is largely dependent upon the hemodynamic disturbance produced by multiple defects associated with a given congenital heart defect (CHD).
