Impact of hypoxemia and re-interventions on clinical outcomes after bidirectional cavopulmonary shunt

OBJECTIVES: We sought to investigate the impact of early postoperative low arterial oxygen saturation on mortality and morbidity after bidirectional cavopulmonary shunt (BCPS). METHODS: The medical records of all patients who underwent BCPS between 2013 and 2018 were reviewed. RESULTS: A total of 164 patients were included in this study. Forty-seven patients underwent reintervention during hospital stay at median 7 days after BCPS. Before reintervention, 30 patients were intubated or had SpO2 of <75%. All re-interventions for Glenn pathway obstruction and 4 out of 5 venovenous coil embolization resulted in hospital discharge, while high mortality was observed after other re-interventions (atrioventricular valve surgery, thrombolysis, systemic ventricular outflow obstruction relief, extracorporeal membrane oxygenation implantation and diaphragmatic plication). Additional aortopulmonary shunt with pulmonary artery discontinuation was performed in 8 patients who showed severe cyanosis with median SpO2 of 59% under maximal ventilation support. In the univariable Cox regression analysis, the associated factors for mortality before total cavopulmonary connection were reduced ventricular function [hazard ratio (HR) 6.89, 95% confidence interval (CI) 1.76-26.9, P-value 0.006], greater than moderate atrioventricular valve regurgitation (HR 5.89, 95% CI 1.70-20.4, P-value 0.005), SpO2 1 h after extubation (HR 0.87, 95% CI 0.80-0.96, P-value 0.004) and mean pulmonary artery pressure 1 h after extubation (HR 1.14, 95% CI 1.02-1.26, P-value 0.016). CONCLUSIONS: After BCPS, unacceptable cyanosis persisted with various aetiologies. Low arterial oxygen saturation within 1 h after extubation is significantly associated with high mortality after BCPS.