High-pressure pulmonary artery aneurysm and unilateral pulmonary artery agenesis in an adult.

The presence of a pulmonary artery aneurysm, major aortopulmonary and coronary-pulmonary collateral vessels, and severe pulmonary hypertension in an adult with unilateral pulmonary artery agenesis and previous patent ductus arteriosus ligation is very rare. A 34-year-old man experienced these conditions. When he was 10 years old, catheterization and angiography revealed right pulmonary artery agenesis, dilation of the main pulmonary artery, multiple collateral vessels extending from the aorta to the right pulmonary system, and a patent ductus arteriosus (shunt ratio, 3.57) that was then ligated; the other conditions were not corrected. This adult patient was in New York Heart Association functional class II; mild central cyanosis was detected only during exercise. The right pulmonary arterial system was seen only at the right hilar area via collateral vessels from the subclavian, bronchial, internal mammary, and intercostal arteries. Angiography revealed collateral vessels from the right and circumflex coronary arteries to the right pulmonary system. The right intraparenchymal pulmonary arterial systems were patent but of small diameter (pulmonary artery pressure, 85 mmHg; ratio of peak right-to-left ventricular pressure, 0.94; peak pulmonary pressure unresponsive to 100% oxygen). Pulmonary vascular resistance was not estimated because of the risk of aneurysmal rupture. We concluded that irreversible pulmonary hypertension had developed (delayed by the patent ductus arteriosus ligation in childhood) and that the patient's only chance for survival was heart-lung transplantation. To sustain the patient until surgery, we administered sildenafil. Herein, we describe the vascular conditions that accompany unilateral absence of the pulmonary artery, and therapeutic methods.