Shunt Failure—Risk Factors and Outcomes: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

Background: Systemic-to-pulmonary shunt failure is a potentially catastrophic complication. We analyzed a large multicenter clinical registry to describe the prevalence and evaluate risk factors. Methods: Infants (aged ≤365 days) undergoing shunt operations (systemic artery-to-pulmonary artery or systemic ventricle-to-pulmonary artery) in The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) from 2010 to 2015 were included. Multivariable logistic regression was used to evaluate risk factors for in-hospital shunt failure. Model covariates included patient characteristics, preoperative factors, procedural factors including shunt type, and center effects. Centers with more than 15% missing data for key covariates were excluded. Results: Shunt operations were performed in 9,172 infants (118 centers). In-hospital shunt failure occurred in 674 (7.3%). In multivariable analysis, risk factors for in-hospital shunt failure included lower weight at operation (odds ratio [OR], 1.35; p = 0.001), preoperative hypercoagulable state (OR, 2.47; p = 0.031), and the presence of any other STS-CHSD preoperative risk factors (OR, 1.24; p = 0.038). Shunt failure was less likely with a systemic ventricle-to-pulmonary artery shunt than a systemic artery-to-pulmonary artery shunt (OR, 0.65; p = 0.020). Neither cardiopulmonary bypass nor single-ventricle diagnosis was a risk factor for shunt failure. Patients with in-hospital shunt failure had significantly higher rates of operative mortality (31.9% vs 11.1%, p < 0.001) and major morbidity (84.4% vs 29.4%, p < 0.001), and longer median postoperative length of stay among survivors (45 vs 22 days, p < 0.001). Conclusions: In-hospital shunt failure is common, and associated mortality risk is high. These data highlight at-risk patients and procedural cohorts that warrant expectant surveillance and may benefit from enhanced antithrombotic prophylaxis or other management strategies to reduce shunt failure. These findings may inform planning of future clinical trials.