Factor XIII Substitution in Surgical Cancer Patients at High Risk for Intraoperative Bleeding

Background: Excessive intraoperative bleeding is associated with significant morbidity and mortality. The authors and others have shown that fibrin monomer allows preoperative risk stratification for intraoperative blood loss, likely due to an imbalance between available factor XIII and prothrombin conversion. The authors hypothesized that the use of factor XIII would delay the decrease of clot firmness in high-risk patients. Methods: The concept was tested in a prospective, randomized, double-blind, placebo-controlled trial in elective gastrointestinal cancer surgery. Patients were randomized to receive factor XIII (30 U/kg) or placebo in addition to controlled standard therapy. Results: Twenty-two patients were evaluable for a planned interim analysis. For the primary outcome parameter maximum clot firmness, patients receiving factor XIII showed a nonsignificant 8% decrease, and patients receiving placebo lost 38%, a highly significantly difference between the two groups (P ‫؍‬ 0.004). A reduction in the nonprimary outcome parameters fibrinogen consumption (-28%, P ‫؍‬ 0.01) and blood loss (-29%, P ‫؍‬ 0.041) was also observed in the factor XIII group. Three patients experienced adverse events that seemed unrelated to factor XIII substitution. The trial was stopped early after a planned interim analysis with the primary endpoint reached. Conclusions: This proof of concept study confirms the hypothesis that patients at high risk for intraoperative blood loss show reduced loss of clot firmness when factor XIII is administered early during surgery. Further clinical trials are needed t