Shunt choice in single right ventricle patients: an update

Hypoplastic left heart syndrome, the most common complex congenital heart malformation, is characterized by underdeveloped left-sided heart structures. The Norwood procedure followed by two-staged operations has permitted the extended survival of many of these patients. Survival, however, remains suboptimal with most of the morbidity and mortality occurring during the Norwood procedure hospitalization. The modified Blalock-Taussig shunt has been implicated in contributing to the mortality risk due to decreased systemic diastolic blood pressure and coronary perfusion. Therefore, the right ventricle-to-pulmonary artery shunt was recently reevaluated as a lower-risk source of pulmonary blood flow in the Norwood procedure. The Pediatric Heart Network Single Ventricle Reconstruction trial, sponsored by the NIH National Heart, Lung and Blood Institute, evaluated the two types of shunts during the Norwood procedure. This randomized clinical trial has yielded important insight into the effects of shunt selection on morbidity, mortality, hemodynamics and overall current outcomes for hypoplastic left heart syndrome.