THE RISK OF RECURRENT VENOUS THROMBOEMBOLISM IN PATIENTS WITH AND WITHOUT FACTOR-V-LEIDEN

Thromboprophylaxis with oral anticoagulants up to six months is establ ished in patients after a first venous thromboembolic event (VTE). The risk of recurrent VTE is still considerable thereafter, and it is unc ertain whether some patients might benefit from extended anticoagulati on. We performed a prospective, multicenter trial (4 thrombosis center s) and evaluated in 380 patients with a first or recurrent VTE (patien ts with a deficiency of antithrombin, protein C, protein S or plasmino gen; cancer or an antiphospholipid antibody syndrome were excluded) th e risk of recurrence after discontinuation of secondary thromboprophyl axis with oral anticoagulants. It was the aim of the study to evaluate whether patients with factor V Leiden are at an increased risk of rec urrent VTE. 112 (29.5%) patients were carriers of factor V Leiden (26. 9% heterozygous, 2.6% homozygous). After a median observation time of 19.3 months the overall recurrence rate of VTE was 9.9%. Recurrent dee p vein thrombosis and/or pulmonary embolism occurred in 26 of 268 pati ents without factor V Leiden (9.7%) and in 10 of 112 patients with fac tor V Leiden (8.9%). The probability of recurrent VTE two years after discontinuation of oral anticoagulants was 12.4% (95% CI 7.8-17) in pa tients without factor V Leiden and was 10.6% (95% CI 3.8-17.4) in carr iers of the mutation. This difference was statistically not significan t. Patients with factor V Leiden are not at a higher risk of recurrent VTE within two years after discontinuation of oral anticoagulants tha n patients without factor V Leiden. Balancing the risk of recurrent VT E and bleeding from oral anticoagulants, patients with factor V Leiden are not likely to benefit from oral anticoagulant therapy extended be yond six months.