Better Selection of Patients for Extended VTE Therapy: The most common and dif cult decision about whether to stop anticoagulants after a time- limited course or to use extended therapy is in patients with a rst unprovoked proximal DVT or PE without a high risk of bleeding. In this subgroup of patients, patient sex and D-dimer level measured about 1 month after stopping anticoagulant therapy can help to further stratify the risk of recurrent VTE.66-69 Men have about a 75% higher (1.75-fold) risk of recurrence compared with women, whereas patients with a positive D-dimer result have about double the risk of recurrence compared with those with a negative D-dimer, and the predictive value of these two factors appears to be additive. The risk of recurrence in women with a negative posttreatment D-dimer appears to be similar to the risk that we have estimated for patients with a proximal DVT or PE that was provoked by a minor transient risk factor (approximately 15% recurrence at 5 years); consequently, the argument for extended anticoagulation in these women is not strong, suggesting that D-dimer testing will often in uence a woman s decision. The risk of recurrence in men with a negative D-dimer is not much less than the overall risk of recurrence that we have estimated for patients with an unprovoked proximal DVT or PE (approximately 25% compared with approximately 30% recurrence at 5 years); consequently, the argument for extended anticoagulation in these men is still substantial, suggesting that D-dimer testing will often not in uence a male s decision. Because there is still uncertainty about how to use D-dimer testing and a patient s sex to make decisions about extended therapy in patients with a rst unprovoked VTE, we have not made recommendations based on these factors. 