Evaluation of fibrinogen function by CFF-A10 in cardiac surgery

Fibrinogen function is evaluated as the maximum amplitude (MA) of the citrated functional fibrinogen (CFF) assay in TEG6s®, however, CFF-MA requires a long time to obtain results. CFF-A10 (10-minute value), allowing more rapid decisions, however, no studies have evaluated the correlation between CFF-A10 levels and fibrinogen concentration. This study aimed to assess the correlation between CFF-A10 and blood fibrinogen levels measured using the dry hematology method after cardiopulmonary bypass (CPB). This retrospective study was conducted in a single university hospital and enrolled 192 patients of all ages who underwent cardiovascular surgery with CPB between 01 March 2020, and 05 November 2021. CFF-A10 and CFF-MA levels were measured using the TEG6s® global hemostasis assay, and blood fibrinogen levels were measured using the Fibcare® DRIHEMATO Fib-HSII after CPB. Simple linear regression analysis was used to evaluate the relationship between TEG6s® parameters and fibrinogen concentration. Furthermore, the patients were classified into four groups based on the cut-off values of fibrinogen at 150 mg/dL and CFF-A10, and the background factors for each group were analyzed. CFF-A10 and blood fibrinogen levels were correlated by linear regression (p < 0.0001, R2 = 0.37), similar to CFF-MA and fibrinogen levels (p < 0.0001, R2 = 0.40). The optimal cut-off value, which maximizes the sensitivity and specificity, of CFF-A10 for predicting low fibrinogen levels below 150 mg/dL, was 8.4 mm, with a sensitivity of 80.7% and specificity of 67.9%; that of CFF-MA was 9.2 mm, with a sensitivity of 76.3% and specificity of 69.8%. Despite sufficient blood fibrinogen levels, patients with low CFF-A10 levels experienced more postoperative bleeding. CFF-A10 predicted fibrinogen loss faster and with the same accuracy as CFF-MA did. Low CFF-A10 levels, despite sufficient fibrinogen levels, may be associated with increased blood loss following CPB.