Postoperative Packed Red Blood Cell Transfusions Are Associated with Thrombotic Events in the Pediatric Cardiac Intensive Care Unit

Objectives: Blood transfusions are common maneuvers after cardiac surgery in pediatric patients who are prone to bleeding. However, risk and benefit of blood transfusions are still debatable. We hypothesize that transfusion products are associated with a higher risk of thrombosis in this specific patient population.

Methods: The current study was designed as retrospective single-center study of 897 patients younger than 18 years in the cardiac intensive care unit (CICU) following cardiac surgery between November 2016 and March 2018. Thrombosis events during the CICU stay served as primary outcome. We confirmed thrombosis events by imaging or by clinical presentation together with necessary anticoagulation or surgical interventions. Packed red blood cells (PRBC), platelets, plasma, cryoprecipitate, and cell saver given postoperatively within the first day of surgery served as primary predictors. We used logistic regression modeling, adjusting for a propensity score (PS). For each blood product, a PS was constructed by age at admission, diagnosis, and pre-CICU history of thrombosis. In a second model, we investigated in the number of blood products using a logistic regression model adjusting for age at admission and history of pre-CICU thrombosis.

Results: The median age at admission to the CICU was 1.53 years, IQR = 0.29, 5.56. Out of the entire cohort, 46 (5.1%) experienced thrombosis. There was no association between cell saver transfusions and thrombotic events (OR = 4.88; 95% CI = 0.29, 83.32). PRBC, platelets, FFP, and cryoprecipitate were all associated with a significantly higher risk of thrombosis after adjusting for PS (p < 0.05). When adjusting for PS and other blood products, PRBC transfusion was the only blood product associated with thrombosis events (OR = 2.03; 95% CI = 1.06, 3.89). The results in our second model showed that there was nearly a twofold risk of thrombosis for every additional blood product used, independent of age and history of pre-CICU thrombosis (OR = 1.88; 95% CI = 1.40, 2.51).

Conclusion: Every additional blood product given to pediatric patients following cardiac surgery increases the risk of thrombosis in the CICU significantly. In particular, PRBC transfusions might expose these patients to a higher risk of thrombotic events. Despite clinical indications, administration of blood products should be re-evaluated to prevent complications from thrombotic events.