Thoracoabdominal aneurysm (TAAA) repair is a major elective vascular operation associated with a large blood loss and potentially life-threatening clotting abnormalities. Theses clotting abnormalities are principally treated using fresh frozen plasma (FFP) (derived from human blood donations), the administration of which carries a number of risks including virus transmission (human immunodeficiency virus (HIV), hepatitis B, hepatitis C) and infection with variant Creutzfeld-Jacob disease (vCJD). FFP is no longer administered to children or high-usage adults in the UK because of the infection risk, and recently it was decided by a UK advisory body that the use of UK-derived FFP should cease.

Fibrinogen concentrate is an alternative treatment option to FFP which is thought have less infection risk (purified, heat treated) and has been in licensed use for many years in other European countries. The investigators have been using fibrinogen concentrate recently in their department as an alternative to FFP with encouraging results.

20 patients undergoing elective TAAA repair at The Royal Infirmary of Edinburgh will be randomly allocated to receive standard treatment (FFP) or fibrinogen concentrate as treatment for clotting abnormalities during their surgery. The investigators will take a number of additional blood samples which will provide valuable information about the pattern of clotting abnormalities during this type of operation. The investigators will also record blood loss and the number of allogeneic (derived from human donors) blood components transfused to the patient (red cells, FFP and platelets). Our primary objective is to assess the pattern of coagulation abnormalities in both groups. We will also examine whether the use of fibrinogen concentrate during TAAA repair avoids the need to administer FFP.

Inclusion Criteria:

• Undergoing elective thoracoabdominal aneurysm repair.
• Over 18 years of age.
• Able to give written informed consent.

Exclusion Criteria:

• Previous aortic surgery (re-do surgery).
• Emergency surgery.
• Pregnancy.
• Females of child-bearing age (less than 45 years) not using medically approved method of contraception.
• Congenital or acquired coagulopathy.
• Known allergy to study drug.