Syndromes associated with hypoplasia or aplasia of one pulmonary artery

An absent pulmonary artery can occur with a normal heart or with Fallot's tetrad. The affected lung is smaller because there is no erectile expansion of its alveoli. There is greatly increased bronchial circulation which may cause h˦moptysis, and result in an increased left ventricular output. Similar circulatory changes occur in gross bronchiectasis. A vascular abnormality may be simulated by a unilateral emphysema or bronchiectasis and the cardio-angiogram is not completely diagnostic. In all these syndromes the bronchographic appearances are specific, and bronchography therefore appears to be a more useful investigation. The appearances due to obstruction of a pulmonary artery may be the main radiological evidence of a bronchogenic carcinoma. A case of atrial septal defect in which there was difference in size of the primary branches of the pulmonary artery is described.