Outcome of Patients with Venous Thromboembolism and Factor V Leiden or Prothrombin 20210 Carrier Mutations During the Course of Anticoagulation

Prothrombotic genotypes and risk of major bleeding in patients with incident venous thromboembolism

“…It is important to address that patients undergoing thrombophilia testing generally do not share the clinical characteristics of unselected VTE patients derived from a general population. For instance, in the above mentioned study, 16 the proportion of VTE patients with cancer was relatively low (6%-11% among carriers and noncarriers of the prothrombotic genotypes studied) as compared to the present study (24%). Therefore, the study from Tzoran et al is not necessarily comparable to our population-based cohort.…”

“…The association between prothrombotic genotypes and risk of MB has been scarcely investigated in a VTE population under anticoagulant treatment. 16,17 In a Dutch case-control study that used data from the FACTors in ORal anticoagulation Safety (FACTORS) study, 26 Garcia et al 17 found that the risk of MB during anticoagulation with VKAs in non-OO blood group carriers was 30% lower than in carriers of OO blood group. Even though risk estimates pointed towards a protective effect (odds ratios = 0.7, 95% CI 0.4-1.1), the 95% CIs were somehow wide and included unity in the aforementioned report.…”

“…In a study derived from the RIETE-registry comprising 10139 VTE patients tested for thrombophilia, Tzoran et al 16 investigated the impact of FVL on the risk of MB during anticoagulation. Compared to noncarriers, FVL carriers (n = 1384) had a 50% (HR 0.50, 95% 0.25-0.99) lower risk of MB.…”

“…For instance, FVL is associated with resistance to the natural anticoagulant protein C, 13 prothrombin G20210A with increased plasma levels of prothrombin, 14 and non-O blood type with increased plasma levels of von Willebrand factor and coagulation factor VIII. 15 The few studies addressing the impact of prothrombotic genotypes on the risk of MB during anticoagulant therapy have suggested a decreased risk of MB in carriers of FVL 16 and non-O blood types. 17 In the context of VTE, de Haan and colleagues developed a genetic risk score originally based on 31 VTE-associated SNPs that was shown to improve the risk prediction of first lifetime VTE.…”

Editor's Choice – European Society for Vascular Surgery (ESVS) 2021 Clinical Practice Guidelines on the Management of Venous Thrombosis

“…377,378 For patients with hereditary thrombophilia the prolongation of anticoagulant treatment should be considered after careful evaluation of the number of previous VTE episodes, the presence of provoking factors, the proximal extent of the thrombosis, symptom severity, type of thrombophilia, bleeding risk, and patient preferences. 379…”