Many patients with a history of pulmonary embolism, especially young or middle-aged, ask about discontinuation of anticoagulant treatment. What would be your advice in such cases? Would you rather recommend long-term anticoagulation or only a short-term therapy lasting a few months? If you recommend the discontinuation of anticoagulation, what precautions would you advise? Would you recommend D-dimer monitoring?
Jeffrey Weitz: The duration of anticoagulation in patients with venous thromboembolism (VTE) is always a question. The first thing we have to determine is whether the VTE was provoked or unprovoked. If it was provoked, whether it was provoked by a major transient risk factor like surgery or trauma, or whether it was provoked by such things as estrogen therapy: either the birth control pill or hormone replacement therapy.
In patients with provoked VTE, a 3-month course of anticoagulation is usually sufficient provided that their risk factor has resolved. In patients with unprovoked VTE, it becomes more difficult because we know that if anticoagulation is stopped at 3 months or 6 months, the risk of recurrence is about 10% at 1 year and about 30% at 5 years. In those patients we really have to balance the risk of recurrence with the balanced risk of bleeding. If they are at high risk for bleeding, we probably would stop at 3 or 6 months and just follow them. But if they are not at high risk for bleeding, then we have to get the patients’ preference in there. Some patients would prefer to remain on anticoagulation knowing that their risk of recurrence is high and they want to prevent that. Others want to stop anticoagulation because they are worried about the risk of bleeding, particularly if they want to pursue high-risk activities.
I think that D-dimer testing is useful in some cases and not useful in all cases. For example, in a man with unprovoked VTE we know that if the D-dimer is positive 1 month after stopping anticoagulation, the risk of recurrence in the next year is about 18% to 20%. If the D-dimer is negative, the risk of recurrence is about 10%. I would say that even 10% is too high. I would prefer to keep these patients on extended anticoagulation and I would not bother doing the D-dimer because the risk is high whether it is positive or negative. In a woman with unprovoked VTE, if you stop anticoagulation for a month and then do the D-dimer testing, if the D-dimer test is positive, the risk of recurrence is about 10% after a year. If it is negative, it is about 5%, and at 5% you might be willing to stop. I think it could be helpful in a woman with unprovoked VTE but I do not think it is helpful in men.