['Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality in neonates with complex single-ventricle anatomy undergoing stage I palliation. Hybrid approach is another option for initial single-ventricle palliation. The goal of this study was to determine if there were differences in echocardiographic indices between patients undergoing the hybrid procedure who developed NEC vs. those that did not develop NEC.', 'Retrospective chart review was performed on patients who underwent the hybrid procedure. Patients were included if an echocardiogram with adequate Doppler tracings through the patent ductus arteriosus stent was available. Echocardiographic indices measured included antegrade velocity-time integral (VTI), retrograde VTI, effective VTI, VTI regurgitant fraction, VTI retrograde/VTI antegrade ratio, calculated cardiac output, peak antegrade velocity through the ductal stent, retrograde/antegrade time ratio, and percent regurgitant time. Indices were compared in patients who developed NEC (NEC Group) and those who did not develop NEC (No NEC Group). NEC was defined as a Bell Stage ≥2.', 'Sixty-nine patients met inclusion criteria. Eight of the 69 patients developed NEC. There was no significant difference between the NEC and No NEC Group for antegrade VTI (10.4\u2009±\u20093.2\u2009cm vs. 12.7\u2009±\u20094.4\u2009cm), retrograde VTI (5.3\u2009±\u20091.5\u2009cm vs. 6.1\u2009±\u20092.2\u2009cm), effective VTI (5.1\u2009±\u20092.9\u2009cm vs. 6.6\u2009±\u20093.3\u2009cm), VTI regurgitant fraction (53.6\u2009±\u200914.7% vs. 49.7\u2009±\u200913.6%), and VTI retrograde/VTI antegrade ratio (0.54\u2009±\u20090.15 vs.0.50\u2009±\u20090.14). Cardiac output (4.2\u2009±\u20091.4\u2009L/min/m(2) vs. 4.8\u2009±\u20091.8\u2009L/min/m(2) ) and peak velocity (117.5\u2009±\u200928.9\u2009cm/s and 142.4\u2009±\u200942.6\u2009cm/s) were also not different between the NEC and No NEC Groups. Furthermore, retrograde/antegrade time ratios (1.6\u2009±\u20090.2 vs. 1.7\u2009±\u20090.3) and percent retrograde time (60.6\u2009±\u20093.0% vs. 62.0\u2009±\u20094.0%) were not different between the NEC and No NEC Groups.'] Are diastolic flow parameters sensitive in predicting necrotizing enterocolitis in patients undergoing hybrid procedure?