Determinants of Adverse Outcomes After Systemic-To-Pulmonary Shunts in Biventricular Circulation

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Systemic-to-pulmonary shunts are useful palliative procedures, although many teams have been deterred by high mortality and morbidity. We aimed to identify predictors of adverse outcomes after shunts in biventricular lesions. From 2004 to 2014, 173 children had shunt procedures. Morphologies included: tetralogy of Fallot, pulmonary atresia with ventricular septal defect (VSD) with and without major aortopulmonary collaterals (MAPCAs), transposition of great arteries with pulmonary stenosis, and double outlet right ventricle. Median age was 22 days (range, 3 to 3,438 days) and median weight 3.2 kg (range, 1.7 to 20 kg). Shunt sizes ranged from 3 to 5 mm with median shunt size/weight ratio 1.03 mm/kg (range, 0.3 to 2.5 mm/kg). In-hospital mortality was 5.2% for the initial shunt procedure. Inter-stage mortality was 3.6%. Overall, 86% of patients progressed to corrective surgery. Acute events were observed in 41 patients, leading to 6 deaths. Events included 30 emergency chest openings, 16 shunt thrombosis, and 17 pulmonary overcirculation. Independent predictors of acute events or in-hospital mortality were genetic or extracardiac anomalies (hazard ratio [HR]= 1.9, p= 0.04), and preoperative shock/acidosis (HR= 2.73, p=0.003). Diagnosis of pulmonary atresia with VSD and MAPCAs was protective (HR= 0.23, p=0.042). Weight, shunt size, and size/weight ratios were not significant risk factors. Shunt thrombosis occurred at a median 3 hours (range, 0 to 46 hours) postoperatively, leading to 33% of in-hospital deaths. Low postoperative oxygen saturation and higher platelet counts in intensive care were independent predictors of thrombosis (p= 0.022, p=0.005 respectively). Early adverse events contribute to mortality and morbidity for the shunt procedure. Patients with lower oxygen saturation and higher platelet counts in the postoperative period are at higher risk of shunt thrombosis.