What should be the duration of anticoagulation treatment in a patient after an episode of venous thromboembolism (VTE) with confirmed hypercoagulability? Which patients need lifelong treatment? In whom can we consider discontinuation?
Mark Crowther, MD: That is a difficult question. The reason it is difficult is that we do very little hypercoagulability testing anymore. It really is unclear to many of us what the value of thrombophilia testing is. There are some thrombophilias that are clearly associated with a need for a long-term anticoagulation. I think that most of us would think that persistent positivity of the antiphospholipid antibody syndrome would be an indication for a long-duration anticoagulation.
Some of the more serious thrombophilias like protein C, protein S deficiency, particularly if it is severe, or severe antithrombin deficiency would be an indication for a long-term anticoagulation. But the common thrombophilias like factor V Leiden and the prothrombin gene mutation probably do not meaningfully influence our decisions about anticoagulants. In fact, to the extent that when I was the chief of laboratory medicine in our hospital, I banned thrombophilia testing. It cannot be performed by anybody except the thrombosis service because I think the ability to access thrombophilia testing actually causes harm. Because it leads patients who should not have their anticoagulants continued to have their anticoagulants continued, and it leads patients to avoid things like the use of birth control pills when in fact there is relatively little good-quality evidence whether or not a patient with an asymptomatic thrombophilia, for example, should avoid the birth control pill.
There are a small group of potent procoagulant states where I think a long-duration anticoagulation is indicated. The real decision point is not whether the person has a hypercoagulable state. It is what you think their risk of recurrent thrombosis is. Work done by Clive Kearon and many other suggested if your patient is male, has the first episode of deep vein thrombosis (DVT) or pulmonary embolism (PE), and has no contrary indications to ongoing anticoagulation, they should probably be left on anticoagulants irrespective of whether they have a thrombophilia. And the ability to use the very low doses of direct oral anticoagulants (DOACs), 10 mg of rivaroxaban or 2.5 mg twice a day of apixaban, really have made that a very simple and easy to administer treatment.
The question is a hard one. Many patients should be continued on a long-term anticoagulation, but based on the nature of their clot and their personal characteristics—not based on the presence or absence of a hypercoagulable state.