Venous thromboembolism (VTE), which includes deep venous thrombosis (DVT) and pulmonary embolism (PE), continues to be a major cause of morbidity and mortality among hospitalized patients. Although it is well-known that anticoagulation therapy is effective in the prevention and treatment of VTE events, these agents are some of the highest-risk medications a hospitalist will prescribe given the danger of major bleeding. With the recent approval of several newer anticoagulants, it is important for the practicing hospitalist to be comfortable initiating, maintaining, and stopping these agents in a wide variety of patient populations.
In February 2016, an update to the ninth edition of the antithrombotic guideline from the American College of Chest Physician (ACCP) was published and included updated recommendations on 12 topics in addition to three new topics. This 10th-edition guideline update is referred to as AT10.1
One of the most notable changes in the updated guideline is the recommended choice of anticoagulant in patients with acute DVT or PE without cancer. Now, the direct oral anticoagulants (DOACs) dabigatran, rivaroxaban, apixaban, or edoxaban are recommended over warfarin. Although this is a weak recommendation based on moderate-quality evidence (grade 2B), this is the first time that warfarin is not considered first-line therapy. It should be emphasized that none of the four FDA-approved DOACs are preferred over another, and they should be avoided in patients who are pregnant or have severe renal disease. In patients with DVT or PE and cancer, low-molecular-weight heparin (LMWH) is still the preferred medication. If LMWH is not prescribed, AT10 does not have a preference for either a DOAC or warfarin for patients with cancer.
When it comes to duration of anticoagulation following a VTE event, the updated guideline continues to recommend three months for a provoked VTE event, with consideration for lifelong anticoagulation for an unprovoked event for patients at low or moderate bleeding risk. However, it now suggests that the recurrence risk factors of male sex and a positive D-dimer measured one month after stopping anticoagulant therapy should be taken into consideration when deciding whether extended anticoagulation is indicated.
AT10 also includes new recommendations concerning the role of aspirin for extended VTE treatment. Interestingly, the 2008 ACCP guideline gave a strong recommendation against the use of aspirin for VTE management in any patient population. In the 2012 guideline, the role of aspirin was not addressed for VTE treatment. Now, AT10 states that low-dose aspirin can be used in patients who stop anticoagulant therapy for treatment of an unprovoked proximal DVT or PE as an extended therapy (grade 2B). The significant change in this recommendation stems from two recent randomized trials that compared aspirin with placebo for the prevention of VTE recurrence in patients who have completed a course of anticoagulation for a first unprovoked proximal DVT or PE.2,3 Although the guideline doesn’t consider aspirin to be a reasonable alternative to anticoagulation for patients who require extended therapy and are agreeable to continue, for patients who have decided to stop anticoagulation, aspirin appears to reduce recurrent VTE by approximately one-third, with no significant increased risk of bleeding.
Another significant change in AT10 is the recommendation against the routine use of compression stockings to prevent postthrombotic syndrome (PTS). This change was influenced by a recent multicenter randomized trial showing that elastic compression stockings did not prevent PTS after an acute proximal DVT.4 The guideline authors remark that this recommendation focuses on the prevention of the chronic complications of PTS rather than treatment of the symptoms. Thus, for patients with acute or chronic leg pain or swelling from DVT, compression stockings may be justified.