Two adult cases of unilateral absence of the right pulmonary artery with markedly different clinical presentations.

Two adult cases of unilateral absence of the right pulmonary artery with markedly different clinical presentations are reported. One patient was a 21-year-old female without any known history of a coexisting congenital anomaly. An abnormal chest roentgenogram (small right hemithorax, deviation of the mediastinum toward the right side and a dilated left pulmonary artery) was noted and prompted further evaluation. No pulmonary hypertension was noted and the patient remained asymptomatic. The other patient was a 42-year-old male who had unilateral absence of the right pulmonary artery and a peripheral stenosis of the left pulmonary artery. The clinical course of this patient had been complicated by impaired exercise tolerance and occasional hemoptysis since adolescence. At the age of 29 years, a cardiac catheterization revealed pulmonary hypertension, but no left-to-right shunt. Progressive respiratory failure resulted in a premature death at the age of 42 years. The prognosis of patients with unilateral absence of the pulmonary artery largely depends on the coexisting cardiac anomaly (left-to-right shunt) and pulmonary hypertension. A combination of unilateral absence of the pulmonary artery and contralateral peripheral pulmonary arterial stenosis is very rare, but is an important cause of pulmonary hypertension and gives a worse prognosis for this entity.