“…Reoperation includes valve repair or replacement for systemic AV valve regurgitation, resection of subaortic obstruction, closure of an unintended residual shunt, revision of Fontan pathway obstruction, or Fontan conversion for atrial tachyarrhythmias with or without anatomic abnormalities. 638 Venous collateral channels or arteriovenous malformations in the right lung in the presence of a classic Glenn shunt may be ameliorated by conversion to a modified Fontan procedure. This enables hepatic venous blood to perfuse the right-sided pulmonary vascular bed.…”