[Congenital hypoplasia of the left pulmonary artery and exertion hypoxemia].

The reported case concerns a 12-year-old boy with a congenital hypoplasia of the left pulmonary artery without associated cardiac malformation. At rest, pulmonary function tests were within the normal range, while the patient demonstrated an abnormal dyspnea and hypoxemia during exercise. These symptoms disappeared after left pneumonectomy. Unilateral pulmonary artery hypoplasia can be responsible for exercise hypoxemia due to an intermittent right-to-left shunt or a ventilation-to-perfusion mismatching.