Objective: The purpose of this study was to review the early postoperative course of stage 1 Norwood with Blalock-Taussig shunt (BTS) or right ventricle-to-pulmonary artery conduit (RVPA) and to identify early predictors of failure.
Material and methods: A retrospective analysis was conducted in 33 consecutive neonates who underwent BTS (n=19) or RVPA (n=14) stage 1 Norwood procedure between 2000 and 2005. Pre-, peri-, and postoperative data included: hourly hemodynamics and blood gases, pulmonary to systemic flow ratio, duration of mechanical ventilatory and inotrope support, intensive care and hospital stay. Failure was defined as death or transplantation.
Results: Thirteen patients failed the procedure (39.4%): 10 BTS (52.6%) and 3 RVPA (21.4%). Failure decreased from 61.1% in 2000-2002 to 13.3% in 2003-2005 and was associated with: low systolic, mean and diastolic blood pressure, urine output, pH, base excess, bicarbonates, and high pulmonary to systemic flow ratio within 24 h postoperatively. Arterial oxygen and CO2 pressure, and oxygen saturation did not differ with failure. RVPA had higher diastolic blood pressure and more stable hemodynamics despite similar pulmonary to systemic flow ratio. Duration of mechanical ventilation, inotrope support, intensive care stay were shorter in RVPA. Postoperative echographic ventricular dysfunction and tricuspid regurgitation grade were correlated with failure.
Conclusions: Excessive pulmonary to systemic flow ratio and low blood pressure are associated with failure. High diastolic blood pressure more than low pulmonary to systemic flow ratio seems to account for more favorable outcomes in RVPA compared to BTS procedure.