title: Increased risk for postoperative hemorrhage after intracranial surgery in patients with decreased factor XIII activity: implications of a prospective study.
abstract: OBJECTIVE
  The functional integrity of the hemostatic system is a prerequisite for the safe performance of neurosurgical procedures. To monitor the individual coagulation capacity of each patient, standard tests are effective to detect deficiencies involving the generation of fibrin. However, fibrin clot strength depends primarily on coagulation factor XIII, which cross-links fibrin monomers and enhances clot resistance against fibrinolysis. Therefore, factor XIII is functionally involved in both the hemostatic and fibrinolytic systems. The objective of this prospective study was to determine the incidence and clinical relevance of perioperative decreased factor XIII with respect to standard coagulation parameters and the occurrence of postoperative hematoma.
  
  
  METHODS
  In 876 patients, 910 neurosurgical procedures were performed. Prothrombin time (PT), partial thromboplastin time (PTT), platelet count, fibrinogen, and factor XIII were tested in each patient preoperatively and postoperatively.
  
  
  RESULTS
  Postoperative intracranial hematoma (defined as requiring surgical evacuation) occurred after 39 (4.3%) of 910 surgical procedures. Patients with postoperative hematoma had significantly lower factor XIII and fibrinogen levels preoperatively and postoperatively than patients without hematoma. In patients with postoperative hematoma, PT and platelets differed significantly only postoperatively, whereas PTT was different neither preoperatively nor postoperatively. Of the 39 patients with a postoperative hematoma, 13 (33.3%) had a postoperative factor XIII <60% compared with 61 (7%) of 867 patients without hematoma (P<0.01, Fisher's exact test). The relative risk of developing a postoperative hematoma is therefore increased 6.4-fold in patients with postoperative factor XIII <60%. The risk is increased 12-fold in patients who additionally have postoperative decreased fibrinogen levels (<1.5 g/L) and 9-fold in patients with platelet count <150x10(9)/L and factor XIII <60%.
  
  
  CONCLUSIONS
  This is the first prospective study that demonstrates the association of decreased perioperative factor XIII with an increased risk of postoperative hematoma in neurosurgical patients. The risk is further increased in those patients with low factor XIII and additional abnormalities of fibrinogen, PT, platelets, and PTT. Factor XIII testing and specific replacement, as accepted for other clotting factors, may reduce the risk of postoperative hematoma.
authors.affiliation: Department of Neurosurgery, Johann Wolfgang Goethe University, Frankfurt/Main, Germany. r.gerlach@em.uni-frankfurt.de
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Gerlach
authors.forename: Fabian
authors.initials: F
authors.lastname: Tölle
authors.forename: Andreas
authors.initials: A
authors.lastname: Raabe
authors.forename: Michael
authors.initials: M
authors.lastname: Zimmermann
authors.forename: Annelie
authors.initials: A
authors.lastname: Siegemund
authors.forename: Volker
authors.initials: V
authors.lastname: Seifert
mesh_terms: D015897:Comorbidity; D005176:Factor XIII / Q000032:analysis; D005177:Factor XIII Deficiency / Q000453:epidemiology*; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D020300:Intracranial Hemorrhages / Q000453:epidemiology*; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects / Q000706:statistics & numerical data*; D010314:Partial Thromboplastin Time; D010976:Platelet Count; D019106:Postoperative Hemorrhage / Q000453:epidemiology*; D011184:Postoperative Period; D011446:Prospective Studies; D011517:Prothrombin Time; D018570:Risk Assessment
chemical_list: D005340:Fibrinogen; D005176:Factor XIII