Factor V Leiden: prevalence and thromboembolic complications after total hip replacement in Ireland

Background The Factor V Leiden (FVL) mutation is the commonest genetic abnormality associated with venous thromboembolism. Aims To determine the prevalence of the FVL mutation in Irish patients undergoing total hip replacement and whether it has an increased risk of deep venous thrombosis or pulmonary embolism (DVT/PE). Methods Prospective screening of 113 patients over 2 years. All had prophylaxis against thrombosis. Symptomatic DVT and PE were diagnosed with venography and ventilation-perfusion scans, respectively. Results The prevalence of the FVL mutation was 2%. Six patients (5.3%) developed a DVT/PE. Half of these had a history of venous thromboembolism (resulting in a higher risk of post operative DVT/PE (P = 0.04, Fischer's exact test) but none had the FVL mutation. Of the remaining 107 patients not developing DVT/PE, 2 had the FVL mutation (heterozygotes). Conclusions The prevalence of the FVL mutation was 2% but was not a risk factor for acute symptomatic DVT/PE.