Editor – I was surprised to find the authors of ‘Portal vein thrombosis – a primer for the general physician’ strongly advocated an extensive search for thrombophilic conditions.1 While these conditions undoubtedly increase the risk of portal vein thrombosis, the question is does knowledge of these mutations alter the subsequent management of the condition or the duration of treatment?
There may be a justification in testing for some thrombophilic conditions, eg identifying myeloproliferative disorders with the JAK2 mutation, and some thrombophilias convey a higher risk of recurrence than others,2 but there is certainly little justification in screening for factor V Leiden and prothrombin gene mutations.
The 2012 National Institute for Health and Care Excellence guidelines for venous thromboembolism (VTE), which are surprising supportive of thrombophilia screening, do not include factor V Leiden and the prothrombin mutation as they do not increase the risk of recurrence to a clinically significant extent.3
In contrast, the 2010 British Society of Haematology guidelines state ‘testing for heritable thrombophilia after a first episode of intra-abdominal vein thrombosis has uncertain predictive value for recurrence. Grade C evidence – as no studies have investigated how the finding of a heritable thrombophilia should influence management’.4
Analysis of the large multiple environmental and genetic assessment study showed that testing for inherited thrombophilia did not reduce recurrence of venous thrombosis.5
The American College of Chest Physicians guidelines on VTE, which recommend ongoing anticoagulation after an unprovoked VTE, list thrombophilias among factors that predict risk of recurrence, ‘but not strongly enough to influence recommendations on duration of therapy’.6 And US guidelines have an equally clear message of ‘do not perform thrombophilia testing in patients following an episode of unprovoked VTE’.2
In summary, thrombophilia is commonly evaluated in patients without a clear indication for testing and not only that, but frequently during times when the results may be unreliable.
Conflicts of interest
The author has no conflicts of interest to declare.
References
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