Evaluation of Thromboelastography 6s prognostication of fibrinogen supplementation in pediatric cardiac surgery

Background: Implementation of point-of-care tests is recommended to provide tailored substitution during cardiac surgery. The measurement and substitution of fibrinogen have gained particular interest since it is the first coagulation factor to become depleted during cardiac surgery. However, the prognostic ability of thromboelastography (TEG) 6s has not been evaluated in pediatric patients. The aim of the present study was to describe patient characteristics of infants receiving fibrinogen substitution during cardiac surgery and evaluate the prognostic ability of TEG6s after weaning off cardiopulmonary bypass (CPB). Methods: Infants undergoing congenital cardiac surgery with CPB were retrospectively included (n - 279) between January 2017 to July 2019. Patient and perioperative data were collected on the day of surgery until 6:00 AM the next morning. Hemostatic capacity was assessed with TEG6s. The efficacy of TEG-functional fibrinogen-maximal amplitude (TEG-FF-MA) measurements for the prediction of intraoperative bleeding, and thereby cryoprecipitate need, was evaluated by a sensitivity and specificity analysis. Results: Among 174 children with TEG-FF-MA data, 147 (84%) received cryoprecipitate intraoperatively. Cryoprecipitate administration was associated with younger age 66 (10-132) versus 98 (45-204) days (p = .044), higher RACHS-1 classification, and intraoperative bleeding 21 (11-47) versus 5 (3-13) ml/kg (p < .001, mean difference 29 ml/kg [CI: 8-50]). Median TEG-FF-MA values were lower in transfused children 7.6 (5.3-11.0) versus 10.5 (7.3-13.4) mm (p =.004, mean difference 2.4 mm [CI: 4.1 to 0.73]). The volume of cryoprecipitate was associated with bypass time, TEG-FF-MA values, and in particular intraoperative bleeding volumes. A TEG-FF-MA threshold of 10.0 mm, resulted in sensitivity: 74%, specificity: 56%, positive predictive value: 80%, and a negative predictive value of 47% for the prediction of intraoperative bleeding (>10 ml/kg) and consequently a need of cryoprecipitate transfusion. Conclusion: Fibrinogen substitution in infants was associated with younger age and higher RACHS-1 category. The prognostic value of TEG6s was evaluated, and cryoprecipitate transfusion was related to TEG-FF-MA values, but also CPB-time, surgical complexity, and in particular excessive intraoperative bleeding. A clear-cut threshold for TEG-FF-MA is difficult to establish in infants undertaken congenital heart surgery.