Abstract 18384: Hybrid Palliation of Hypoplastic Left Heart Syndrome Leads to Lower Systemic and Cerebral Oxygen Delivery than the Surgical Norwood Procedure-A Multiscale Computational Study
Background: The goal of first stage palliation for hypoplastic left heart syndrome (HLHS) is to maximize systemic and cerebral oxygen delivery prior to superior cavopulmonary connection. Whether the hybrid approach leads to equivalent or better oxygen delivery than the surgical Norwood procedures have not been examined.
Methods and Results: Three-dimensional computational models were constructed with finite volume method, using previously published patient-derived geometry. The hybrid stage 1 circulation was modeled with a 7 mm ductal stent, bilateral pulmonary artery banding diameter of 3 mm, and ascending and transverse aorta of 5 mm (Figure). Two surgical Norwood models were constructed with a 3.5mm modified Blalock Taussig shunt (BT Norwood), and a 5mm right ventricular-to-pulmonary artery shunt (RV-PA Norwood). Identical hydraulic networks using lumped resistances, inertances, and elastances to describe the entire human circulatory system were adopted for all models. A multi-scale numerical approach was used to couple the 3-dimensional models with the circulatory network. Computational results predict local pressures and flows, as well as global cardiac output, mixed venous oxygen saturation, and systemic and cerebral oxygen delivery. Hybrid palliation leads to higher pulmonary-to-systemic flow ratio (Qp:Qs), and lower cardiac output than either of the surgical Norwood circulations. Total systemic oxygen delivery was markedly reduced in the hybrid palliation than surgical Norwoods (hybrid: 400, BT Norwood: 591, RV-PA Norwood: 640; all units in ml/min m2). Cerebral oxygen delivery was similarly lower in the hybrid palliation.
Conclusions: These computational results demonstrate the hybrid approach to first stage palliation for HLHS provides poorer systemic and cerebral oxygen delivery than either of the two surgical Norwood procedures.
- © 2010 by American Heart Association, Inc.