Liver transplantation is the only treatment for end-stage liver disease. It is a high-risk surgery that can cause heavy intraoperative bleeding. Bleeding and transfusions of blood products are themselves associated with several postoperative complications. Few data have suggested beneficial interventions that can decrease this bleeding. Such interventions are necessary in order to improve these patients' outcomes. In order to better understand the potential therapeutic targets, a better comprehension of the variables associated with such bleeding is essential. Several previous studies have demonstrated a weak association between usual clotting times and bleeding in this population. However, few studies have evaluated the association between the concentration of fibrinogen and bleeding in this population.

The primary objective of this study is to assess the association between preoperative serum fibrinogen concentration and the volume of intraoperative bleeding. The secondary objective is to assess the association between preoperative serum fibrinogen concentration and the number of red blood cell units transfused during the intraoperative and immediate postoperative periods.

The hypothesis of the study is that a low concentration of preoperative fibrinogen will be associated with an increase in intraoperative bleeding and red blood cell transfusions.

All patients who received a liver transplant between July 2008 and January 2021 at the Centre Hospitalier de l'Université de Montréal (CHUM) will be included. The effect of fibrinogen concentration, intraoperative bleeding, intraoperative and postoperative transfusions, as well as postoperative bleeding-related complications and mortality up to 1 year will be assessed. The analysis will be adjusted for several confounding factors, including other coagulation parameters. The main association model will be a multivariable linear regression.

This study will be used to further explore the association between fibrinogen concentration and bleeding in liver transplantation. These results may help certain clinical decisions, without suggesting any potential effect of fibrinogen correction on clinical outcomes. If an association is found, the bases will be put in place to build a clinical trial evaluating the effects of a preemptive transfusion of blood products correcting this value on clinical outcomes.

Inclusion Criteria:

• Adult patients undergoing liver transplant.

Exclusion Criteria:

• Use of cryoprecipitate or fresh frozen plasma after measurement of serum fibrinogen concentration prior to arrival in the operating room.
• Amyloid neuropathy or liver cancer
• Fulminant hepatitis
• Retransplantation

All patients who underwent a liver transplant for a chronic liver disease during the reference period.