S. Eichinger et al., The risk of early recurrent venous thromboembolism after oral anticoagulant therapy in patients with the G20210A transition in the prothrombin gene, THROMB HAEM, 81(1), 1999, pp. 14-17
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.