Cardiopulmonary Bypass Reduces Early Thrombosis of Systemic-to-Pulmonary Artery Shunts

Background: Shunt thrombosis is a significant cause of morbidity and mortality after systemic-to-pulmonary artery shunt (SPS) placement. Concurrent procedures with placement of SPS may require cardiopulmonary bypass (CPB). Cardiopulmonary bypass is known to cause bleeding and platelet dysfunction in infants, which may protect from early shunt thrombosis. We hypothesized that infants undergoing SPS placement on CPB have a lower incidence of early shunt thrombosis. Methods: Retrospective cohort study of infants undergoing SPS placement from January 2008 to December 2014 was performed. Patients with and without early shunt thrombosis and on or off CPB were compared using the Mann-Whitney U test or Fisher exact test. Multivariable regression analysis was performed to identify independent predictors of early shunt thrombosis and to assess effect of CPB independent of other factors. Results: Seventy-five infants underwent SPS placement during the study period (on CPB, n = 25; off CPB, n = 50). Operative mortality was 11% (8/75). Nine (12%) patients developed early shunt thrombosis, all of whom had shunt placement off CPB. Independent risk factors for early shunt thrombosis were identified to be SPS placement off CPB (P =.011), prematurity (P =.034), and competitive antegrade pulmonary blood flow (P =.038). Conclusion: Prematurity, competitive antegrade pulmonary blood flow, and shunt placement off CPB lead to higher risk of early shunt thrombosis. We speculate that the protection offered by use of CPB may be accounted for by the associated complex coagulopathy and platelet dysfunction associated with CPB.