Background: A point mutation in coagulation factor V (A1691G) is associated with increased risk for venous thrombosis. However, limited information is available about the prospective risk for deep venous thrombosis in specific high-risk clinical settings.
Objective: To determine whether the factor V Leiden mutation is associated with an increased occurrence of deep venous thrombosis in patients undergoing hip or knee replacement surgery.
Design: Retrospective analysis of plasma samples obtained during six prospective clinical trials that compared different antithrombotic prophylaxis regimens in patients undergoing hip or knee replacement surgery.
Setting: Inpatients at the University of Rochester Medical Center, McMaster University Medical Center, Hamilton Civic Hospitals, and the Genesee Hospital.
Patients: 825 patients hospitalized for hip or knee replacement surgery.
Measurements: Venographically diagnosed postoperative deep venous thrombosis was correlated with factor V genotype.
Results: The factor V Leiden mutation was not associated with a significantly increased risk for venographically detected deep venous thrombosis. The absolute incidence of deep venous thrombosis was 31% (95% CI, 15% to 47%) in patients with the mutation and 26% (CI, 22% to 29%) in patients without the mutation (relative risk, 1.2 [CI, 0.6 to 2.9]). The factor V Leiden mutation was not significantly associated with deep venous thrombosis in subgroups of patients receiving warfarin or heparin. The incidence of clinical hemorrhage was similar in patients with (10%) and without (8%) the mutation.
Conclusions: The factor V Leiden mutation is not a significant risk factor for acute deep venous thrombosis in this group of patients. Current data do not justify routine preoperative screening for this mutation or intensified perioperative prophylaxis in patients with the factor V Leiden mutation who are undergoing hip or knee joint replacement surgery and are receiving effective antithrombotic prophylaxis.