Development of pulmonary arteriovenous malformations after modified Fontan operations.

Two patients with complex cyanotic congenital heart disease and without previous Glenn anastomosis underwent modified Fontan operations. Postoperatively, pulmonary arteriovenous malformations developed that resulted in cyanosis from significant intrapulmonary right-to-left shunting. These malformations were detected by pulmonary angiograms and contrast echocardiograms. Pulmonary arteriovenous malformations may be a major cause of late clinical deterioration in patients treated with modified Fontan operations.