Truncus arteriosus. An anatomical-angiographic study.

A series of 25 cases of truncus arteriosus communis examined post mortem was studied retrospectively. Fifteen of them had had angiographic studies, enabling anatomo-radiographic correlative analysis to be made. All cases had situs solitus of the atria and concordant connections between atria and ventricles. The three main components of the malformation, present in all 25 cases, were: (a) ventricular septal defect, (b) single semilunar valve, (c) anomalies of the aortopulmonary septum. The ventricular septal defect was always subarterial but its size and its relation to mitral and tricuspid valves were extremely variable. The truncal valve varied greatly also in the number of its cusps and its relation to right and left ventricles. Above valvular level the presence or absence of residual aortopulmonary septum was reflected by the presence or absence of a main pulmonary artery. Additional supratruncal malformations produced variations of the anatomy of the aorta and pulmonary arteries. The angiographic demonstration of all these components was obtained best by selective angiography using special projections. From this study it appears that there is a wide degree of variability in all of the three main components of truncus arteriosus. Such anatomical variations should be identified angiographically in each patient in order to provide enough information before corrective surgery, but they do not alter the basically homogeneous anatomy of the category of truncus arteriosus and therefore do not justify complex classifications.