Thromboembolic Disease

In patients with established DVT and PE, the FDA approval of several direct oral anticoagulants has led to a significant expansion in the options available to clinicians and patients, both for the treatment of acute VTE and for the secondary prevention against recurrence. When multiple inherited and acquired risk factors are present in the same patient, a synergistic effect may occur. The rate of VTE recurrence in patients with untreated isolated calf DVT is approximately 20% to 30%. In contrast, the rate of recurrence in patients with untreated proximal DVT is more difficult to determine, since the majority of patients with proximal DVT receive therapeutic anticoagulation. Limited older data suggest that about 50% of patients with inadequately treated proximal DVT will develop symptomatic PE. There are no laboratory tests that independently confirm or exclude the presence of DVT or superficial venous thrombosis (SVT). The venous duplex scan is the most commonly performed test for the detection of infrainguinal DVT. Once the diagnosis of VTE has been made, antithrombotic therapy should be initiated promptly. Evidence-based protocols for dosing and duration of anticoagulation are summarized in the chapter.