Persistent truncus arteriosus--an autopsy study of 16 cases.

Sixteen specimens of heart with persistent truncus arteriosus were studied to evaluate the anatomic features. Using the Collet and Edwards classification, type I truncus arteriosus was the most frequent (62.5%). Using Van Praagh's classification type A1 was the most common (43.7%). There were two cases which could not be classified according to the Collet and Edwards classification. The truncal valve was tricuspid in 75% of the cases and bicuspid in the remaining 25%. In all 6 cases with interruption of the aorta, the truncal valve was committed to the right ventricle. The ventricular septal defect was subtruncal in all except 1 case. There was variation in the thickness of the posterior limb of the septal band and the ventriculo-infundibular fold. Absence of the ventriculo-infundibular fold in 3 cases led to truncal tricuspid continuity. Right-sided aortic arch and interruption of the aorta were frequently associated arch anomalies.