The performance of a bidirectional superior cavopulmonary (Glenn) anastomosis as the second stage in the reconstructive approach to hypoplastic left heart syndrome:

A. Provides early relief of volume load on the single right ventricle.

C. Permits concomitant repair of pulmonary artery or aortic arch stenoses.

D. Improves mortality and morbidity of subsequent Fontan procedure.

DISCUSSION: After the first-stage reconstructive (Norwood) procedure, the circulation is inherently inefficient because of the obligatory recirculation of a portion of both saturated and desaturated blood. Closure of the arterial shunt and creation of a bidirectional Glenn anastomosis eliminates this inefficient recirculation and significantly diminishes the volume load on the single right ventricle. Distorted and stenosed central pulmonary arteries or aortic arch obstructions should be repaired at the same time the bidirectional Glenn procedure is performed. In almost all series the mortality of the Fontan procedure has decreased since the adoption of the three-stage approach for hypoplastic left heart syndrome. Because systemic and pulmonary venous blood continue to mix in the right atrium after a bidirectional Glenn procedure, cyanosis persists with peripheral oxygen saturations between 75% and 85%.