Pulmonary arterial changes in patients dying after a modified Fontan procedure following pulmonary artery banding

Pulmonary arterial changes were histometrically analyzed in four cases of postoperative death following a modified Fontan procedure in which pulmonary artery banding had previously been performed because of pulmonary hypertension. Case 1 was a 3-year-old girl with corrected transposition of the great arteries (TGA), ventricular septal defect, and double-inlet left ventricle; case 2 was a 6-year-old girl with single ventricle (SV) and complete TGA; case 3 was a 25-month-old boy with SV and double-outlet right ventricle; and case 4 was a 21-year-old man with tricuspid atresia. The cause of death in cases 1, 2, and 3 was pulmonary hypertensive crisis due to postoperative vasoconstriction of the small pulmonary arteries. Medical hypertrophy remained in half of the preacinar small pulmonary arteries although it was not observed in all the intraacinar arteries in cases 1 and 2, even after banding. The postoperative course of case 4 was uneventful despite multiple thromboembolism in the small pulmonary arteries. However, the patient died due to a thrombosed artificial valve. The results suggest that residual medial hypertrophy of the small pulmonary arteries was a major risk factor in these cases. Lung biopsy is recommended to determine the indications for the Fontan procedure in these hemodynamically critical cases.