Collete and Edward classification Collete and Edward classification Van Praagh classification Van Praagh classification
Type I Both PA arising from a short pulmonary trunk Type A1 Same as type I of Collet and Edward system
Type II Separate origin of the PA from the posterior aspect of the truncus Type A2 Same as type II of Collet and Edward system
Type III Separate origin of the PA from the lateral aspect of the truncus Type A3 Left or right PA atresia, with collateral flow to the ipsilateral lung
Type IV A pseudo truncus (now considered a form of PA atresia with VSD) Type A4 Truncus with associated aortic arch interruption, hypoplasia or coarctation