Pulmonary Venous Atresia as a Mimicker of Chronic Thromboembolic Pulmonary Disease: Diagnostic Utility of Ventilation/Perfusion Scanning.

A man in his 60s was referred to our institution for evaluation of suspected chronic thromboembolic pulmonary disease in the context of progressive exertional dyspnea and a mismatched ventilation/perfusion defect on scintigraphy. The ventilation/perfusion scan revealed complete absence of perfusion to the left hemithorax with preserved ventilation. CT pulmonary angiography demonstrated unilateral pulmonary vein atresia, characterized by absent left pulmonary venous drainage, a hypoplastic pulmonary arterial tree on the affected side, and compensatory hyperinflation of the contralateral lung. This case highlights the distinctive scintigraphic pattern of unilateral pulmonary vein atresia, in which global absent perfusion in the affected hemithorax results from the reversal of pulmonary arterial flow due to elevated pulmonary venous pressures. Additionally, perfusion is further impaired by retrograde bronchial collateralization, compounding the hemodynamic compromise.