Fibrinogen Levels After Cardiac Surgical Procedures: Association With Postoperative Bleeding, Trigger Values, and Target Values

Abstract

Background: Low fibrinogen levels immediately after cardiac surgical procedures have been associated with postoperative bleeding and transfusions. However, no sound data on the adequate trigger values for fibrinogen supplementation and target values for fibrinogen concentration exist.

Methods: This retrospective study examined prospectively collected data, including data on 2,800 adult patients undergoing cardiac operations. Standard coagulation parameters at the arrival in the intensive care unit were retrieved, inclusive of fibrinogen levels. Postoperative bleeding was assessed based on the chest drain output (mL/12 h). Severe bleeding (SB) was defined as chest drain output greater than 1,000 mL/12 h.

Results: Postoperative blood loss was associated with low values of fibrinogen and platelet count, as well as with a prolonged activated partial thromboplastin time and international normalized ratio. At multivariable analysis, fibrinogen levels lower than 220 mg/dL remained independently associated with SB (odds ratio: 2.25; 95% confidence interval: 1.54 to 3.28). A cutoff value of 115 mg/dL yielded a positive predictive value for SB of 50% and may be proposed as a trigger value for fibrinogen supplementation, with a target value of 280 mg/dL (98% negative predictive value for SB). In actively bleeding patients, these values are increased to 215 and 375 mg/dL, respectively.

Conclusions: These data confirm the independent role of fibrinogen levels as determinants of SB after cardiac surgical procedures and suggest adequate cutoff values and fibrinogen concentrate doses to prevent or treat SB. However, the identified trigger and target values should be confirmed in prospective series of patients undergoing fibrinogen supplementation.