title: The influence of VKORC1 and CYP2C9 mutations on warfarin response after total hip and knee arthroplasty.
abstract: OBJECTIVE
  This study characterizes the influence of genotype at two loci on warfarin response after arthroplasty.
  
  
  METHODS
  121 postarthroplasty patients given warfarin thromboprophylaxis were reviewed for international normalized ratio (INR) values on the first three days postoperatively. Significant differences among genotypes in INR values on each of the first three postoperative days were assessed.
  
  
  RESULTS
  Wild-type patients at both loci (∼23% of patients) had yet to reach therapeutic INR (1.5-2.0) by postoperative day three more frequently than those with a mutation conferring hyper-responsiveness (61% vs. 30%; P ≤ .01).
  
  
  CONCLUSIONS
  Wild-type patients are not anticoagulated in a sufficiently prompt manner after arthroplasty.
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232-2730, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Wise
authors.affiliation: Department of Surgery, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Gadomski
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232-2730, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: McMaster
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232-2730, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wilson
authors.affiliation: Department of Surgery, University of Maryland, Baltimore Washington Medical Center, Glen Burnie, MD 21061, USA.
authors.forename: Justin K
authors.initials: JK
authors.lastname: Nelms
authors.affiliation: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232-2730, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: Hocking
authors.affiliation: Department of Surgery, Tennessee Valley Veterans Administration, Nashville, TN 37212, USA; Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232-2730, USA.
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Brophy
keywords: Arthroplasty; Deep venous thrombosis; Genetics; Thromboprophylaxis; Warfarin