Congenital avalvular pulmonary artery and infantile lobar emphysema. A diagnostic correlation.

Some cardiovascular lesions may result in tracheobronchial obstruction and many of these will commonly be associated with infantile lobar emphysema (ILE). By contrast a relatively smaller percentage of cases of ILE results from vascular compression. We offer a new term, "congenital avalvular pulmonary artery (CAPA)," to describe the complex of the absent pulmonary valve and the concomitant marked pulmonary artery dilatation because CAPA is more descriptively inclusive of the abnormality of the artery beyond the valve. The diagnostic correlation of CAPA and ILE is of considerable importance since the initial presentation of CAPA is usually as ILE and the recognition of a triangular or rounded hilar density should raise suspicion for CAPA even before clinical signs become evident. Differential diagnosis must include other causes of ILE including infantile lobar emphysema with bronchial atresia.