title: Factor V Leiden protects against blood loss and transfusion after cardiac surgery.
abstract: BACKGROUND
  The outcome of cardiac surgery is influenced by several factors, but the impact of specific genetic variants has not been systematically explored. Because blood conservation is a pressing issue in cardiac surgery, we tested the hypothesis that factor V Leiden (FVL), a common coagulation factor polymorphism, may protect against blood loss and transfusion in patients undergoing cardiac surgery.
  
  
  RESULTS
  We enrolled 517 patients undergoing cardiac surgery, including 26 heterozygous FVL carriers, and evaluated the impact of FVL on chest tube output and transfusion by using univariate and multivariate techniques. For patients with FVL, blood loss at 6 (238+/-131 mL) and 24 hours (522+/-302 mL) was significantly lower than that for noncarriers (358+/-259 mL and 730+/-452 mL; P<0.001 and P=0.001, respectively). In a multivariate regression analysis, controlling for ethnicity and factors known to affect blood loss, FVL was a significant independent contributor at both time points. Using a similar regression approach, FVL did not have a significant effect on the number of units transfused. However, logistic regression of the risk of receiving any transfusion during hospitalization demonstrated a significant independent protective effect of FVL on overall transfusion risk.
  
  
  CONCLUSIONS
  FVL represents a common genetic trait that may protect against blood loss and transfusion in this population. This study demonstrates that genetic variability can affect the outcome of cardiac surgery.
authors.affiliation: Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tenn 37232, USA. brian.donahue@vanderbilt.edu
authors.forename: Brian S
authors.initials: BS
authors.lastname: Donahue
authors.forename: David
authors.initials: D
authors.lastname: Gailani
authors.forename: Michael S
authors.initials: MS
authors.lastname: Higgins
authors.forename: Davis C
authors.initials: DC
authors.lastname: Drinkwater
authors.forename: Alfred L
authors.initials: AL
authors.lastname: George
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D005165:Factor V / Q000235:genetics*; D005260:Female; D006488:Hemostasis, Surgical; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic
chemical_list: C095381:factor V Leiden; D005165:Factor V