Medico

UpdUpadattee
Applied Physiology to the Contemporary
Management of the Neonate with Hypoplastic Left
Heart Syndrome
Fernando Antibas Atik
Cleveland Clinic Foundation - Cleveland, Ohio - USA
Mailing Address:
Email: [e-mail]
The surgical treatment of hypoplastic left heart syndrome is still a challenge. Few selected large volume centers that adopted protocols focused on understanding of post-Norwood pathophysiology have reduced their mortality rates to around 15%. The inherent inefficacy of the parallel circulation in Norwood operation lends itself to problems related to postoperative management of these patients crucially revolving around keeping a balance between systemic blood flow (Qs) and pulmonary blood flow (Qp). This paper describes the physiology of the Norwood principle, the importance of an adequate hemodynamic assessment, to guide the different postoperative management options.
INTRODUCTION
Hypoplastic left heart syndrome (HLHS) constitutes a spectrum of cardiac anomalies that result in underdevelopment of left-sided heart structures. It is characterized by aortic atresia or severe stenosis with hypoplasia or absence of the left ventricle1. Coarctation of the aorta is usually the most frequent associated anomaly and it may impede retrograde blood flow to a diminutive ascending aorta. Postnatal survival is dependent on the ductus arteriosus patency and shunting at atrial level.
The natural history is almost universally lethal in the first month of life2.
The past decade experienced enormous improvements in the surgical treatment of HLHS. Several current available surgical alternatives have been extensively explored (Table 1). Although multi-institutional studies3 using intention to treat based analyses have demonstrated higher intermediate term survival for patients entered into heart transplantation4, the latter has become less or equally important than the staged palliative surgical