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 (R), 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 (R) global hemostasis assay, and blood fibrinogen levels were measured using the Fibcare (R) DRIHEMATO Fib-HSII after CPB. Simple linear regression analysis was used to evaluate the relationship between TEG6s (R) 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.