Unilateral pulmonary artery agenesis is a congenital abnormality.
It is an isolated defect seen in a proximally one and 200,000 individuals.
It is seen in conjunction with congenital heart defects including: coarctation of the aorta, all, tetrology of Fallot, or septal defects.
If its present as an isolated defect symptoms are often nonspecific in this diagnosis and considerable delay in diagnosis is likely.
Nonspecific symptoms include recurrent pulmonary infections, impaired exercise tolerance and dyspnea on exertion.
Hemoptysis occurs in 20% of patients and is attributed to systemic-pulmonary collateral arteries that are forced to develop early in life.
Collateral blood vessels typically derive from bronchial arteries, although they can come from intercoastal, subdiaphragmatic, subclavian and even coronary arteries.
Collateral blood flow is shunted to thin wall collaterals so that rupture of vessels can occur leading to hemoptysis.
Approximately 15% of patients may reach the seventh decade of life without symptoms.
Diagnosis is most often made on incidental findings on chest x-rays that lead to additional imaging studies.
Chest x-ray findings include decreased volume of the affected lung, a small hilum, hyperexpansion of the contralateral hemithorax with increased vascularity the lung, ipsilateral shift of the mediastinum and opacities or possible rib notching due to collateral vessels.
Usually pneumonectomy and embolization of collateral blood vessels are recommended for patients with recurrent primary infections, hemoptysis, or pulmonary hypertension.
Early in childhood surgical procedures may reestablish blood flow in occult pulmonary arteries.
In adults such revascularization procedures are prone to hemorrhage due to heavy pre-existing scarring.