Thrombophilic abnormalities in recurrence of venous thromboembolism (VTE) in patients treated with standardized anticoagulant treatment

Abstract

Conclusion: Patients with thrombophilic abnormalities and venous thromboembolism (VTE) have an increased risk of recurrence of VTE. Summary: The authors studied the recurrence of VTE in patients with and without thrombophilic abnormalities who were treated with a standardized anticoagulation program. The analysis was from a prospective, multicenter, randomized study evaluating clinical benefit of 1 year of oral anticoagulant treatment vs a 3-month period of oral anticoagulant treatment after a first episode of idiopathic proximal deep vein thrombosis. Patients were screened for protein C and protein S deficiencies, antithrombin, hyperhomocysteinemia, antiphospholipid antibodies, mutation 20210GA of the prothrombin gene, and resistance to activated protein C, Factor-5/R506Q mutation, or both. VTE recurrence was documented by objective testing with ultrasound imaging or catheter-based techniques. An independent committee unaware of the results of thrombophilia screening adjudicated all recurrences. Screening for thrombophilic abnormalities was done in 195 patients. Of 57 patients with detected thrombophilic abnormalities, 20 (35.1%) experienced VTE recurrence compared with 29 (21.0%) of 138 patients without thrombophilia (hazard ratio, 1.78; 95% confidence interval, 1.02 to 3.14; P = .046). Differences in VTE recurrence between patients with and without thrombophilia can be accounted for by patients who received only 3 months of oral anticoagulation (hazard ratio, 3.21; 95% confidence interval, 1.349 to 7.616; P = .008). Comment: Like others before it, this study suggests longer durations of treatment for patients with idiopathic VTE. This study has too few patients to allow precise recommendations for duration of therapy on the basis of the thrombophilic abnormality identified. Nevertheless, it is now quite clear that not all VTE is the same. Patients with thrombophilia should be considered at higher risk of recurrence and probably treated with warfarin for at least 1year after their initial VTE event.