The risk of early recurrent venous thromboembolism after oral anticoagulant therapy in patients with the G20210A transition in the prothrombin gene

A G20210A transition in the prothrombin gene is a common risk factor of ven ous thrombosis. The risk of recurrent venous thromboembolism in carriers of the 20210A allele is unknown and guidelines for secondary thromboprophylax is in these patients are not available. In a prospective multicenter trial, 492 patients with a history of objectiv ely documented venous thromboembolism were followed for a mean observation time of 24 +/- 16 months after discontinuation of oral anticoagulants. Fort y-two patients (8.5%) wen carriers of the 20210A allele, Three of the 42 pa tients with the G20210A mutation (7%) and 54 of 450 patients without the mu tation (12%) experienced recurrent venous thrombosis. At 24 months, the pro bability of recurrence was 8% (95% CI 0-16.7) in patients with the mutation and was 12.2% (95% CI 8.8- 15.6) in patients without the mutation. In conclusion, the risk of early recurrent venous thromboembolism is not hi gher in patients with the G10210A mutation than in those without the mutati on. Therefore, long-term secondary thromboprophylaxis with oral anticoagula nts in heterozygous carriers of the 20210A allele is not justified.