Venous thromboembolism (VTE), consisting of deep venous thrombosis (DVT), pulmonary embolism (PE), or both, is a common disorder with an estimated 900,000 patients each year in the United States and more than 1 million each year in the European Union. Approximately one-third of these cases are fatal pulmonary emboli, and the remaining two-thirds are nonfatal episodes of symptomatic DVT or PE. The majority of fatal events occur as sudden death, underscoring the importance of prevention as the critical strategy for reducing death from PE. Of the nonfatal cases, approximately 60% present clinically as DVT, and 40% present as PE. Most clinically important pulmonary emboli arise from proximal DVT of the leg (popliteal, femoral, or iliac vein thrombosis). Upper-extremity DVT also may lead to clinically important PE. The clinical features of DVT and PE are nonspecific. Objective diagnostic testing is required to confirm or exclude the presence of VTE. A validated assay for plasma D-dimer, if available, provides a simple, rapid, and cost-effective first-line exclusion test in patients with low, unlikely, or intermediate clinical probability. Compression ultrasonography is highly sensitive and specific for clinically important DVT and is the primary imaging test for symptomatic patients. Compression ultrasonography of the proximal veins performed at presentation, and if normal, repeated once 5–7 days later can safely exclude clinically important DVT. In centers with the expertise, a single comprehensive evaluation of the proximal and calf veins with duplex ultrasonography is sufficient. In patients with suspected PE, computerized tomographic angiography, with or without additional testing using computed tomographic venography or compression ultrasonography of the legs, provides a definitive basis to give or withhold antithrombotic therapy in 90% of patients.
Anticoagulant therapy is the preferred treatment for most patients with acute VTE. Initial treatment with heparin or low-molecular-weight heparin (LMWH) followed by long-term treatment with an oral vitamin K antagonist (VKA) such as warfarin is highly effective for preventing recurrent VTE and has been the traditional standard of care. More recently, the direct oral anticoagulants (DOACs), including the thrombin inhibitor dabigatran and the factor Xa inhibitors rivaroxaban, apixaban, and edoxaban, have been established to be as effective as and safer than traditional standard anticoagulant therapy. Rivaroxaban and apixaban can be used as a single-drug approach. Dabigatran and edoxaban are preceded by at least 5 days of heparin or LMWH treatment. The DOACs are preferred over the VKAs in most new patients commencing anticoagulant therapy. In patients with cancer who have VTE, treatment with LMWH for at least 6 months has been the standard approach. Evidence-based practice guidelines now include the DOACs as an option for patients with cancer-associated VTE, with caution recommended for patients who have gastrointestinal cancer. Thrombolytic therapy is indicated for patients with PE who present with hypotension or shock and in selected patients who have impaired right ventricular function who are at high risk of hemodynamic collapse. Insertion of a vena cava filter is indicated for patients who have an absolute contraindication to ...