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Pulmonary embolism (PE) is a potentially life-threatening condition, mandating urgent diagnosis and treatment. The symptoms of PE may be non-specific; diagnosis therefore relies on a clinical assessment and objective diagnostic testing. A clinical decision rule can determine the pre-test probability of PE. If PE is "unlikely", refer for a D-dimer test. If the D-dimer result is normal, PE can be excluded. If D-dimer levels are increased, refer for chest imaging. If PE is "likely", refer for chest imaging. Imaging with computed tomography pulmonary angiogram is accurate and preferred for diagnosing PE, but may detect asymptomatic PE of uncertain clinical significance. Imaging with ventilation-perfusion (VQ) scan is associated with lower radiation exposure than computed tomography pulmonary angiogram, and may be preferred in younger patients and pregnancy. A low probability or high probability VQ scan is helpful for ruling out or confirming PE, respectively; however, an intermediate probability VQ scan requires further investigation. The direct oral anticoagulants have expanded the anticoagulation options for PE. These are the preferred anticoagulant for most patients with PE because they are associated with a lower risk of bleeding, and have the practical advantages of fixed dosage, no need for routine monitoring, and fewer drug interactions compared with vitamin K antagonists. Initial parenteral treatment is required before dabigatran and edoxaban.

Diagnosis of deep vein thrombosis (DVT) requires a multifaceted approach that includes clinical assessment, evaluation of pre-test probability, and objective diagnostic testing. Common symptoms and signs of DVT are pain, swelling, erythema and dilated veins in the affected limb. The pre-test probability of DVT can be assessed using a clinical decision rule that stratifies DVT into "unlikely" or "likely". If DVT is "unlikely", refer for D-dimer test. If the D-dimer level is normal, DVT can be excluded; if the D-dimer level is increased, refer for compression ultrasound. If DVT is "likely", refer for compression ultrasound. When DVT is confirmed, anticoagulation is indicated to control symptoms, prevent progression and reduce the risk of post-thrombotic syndrome and pulmonary embolism. Anticoagulation may consist of a parenteral anticoagulant overlapped by warfarin or followed by a direct oral anticoagulant (DOAC) (dabigatran or edoxaban), or of a DOAC (apixaban or rivaroxaban) without initial parenteral therapy. DOACs are the preferred treatment for DVT because they are at least as effective, safer and more convenient than warfarin. DOACs may require dose reduction or avoidance in patients with renal dysfunction, and should be avoided in pregnancy. Recent evidence shows that DVT in patients with cancer may be treated with edoxaban (after discontinuation of 5 days of initial heparin or low molecular weight heparin [LMWH]) or rivaroxaban if patients prefer not to have daily injections of LMWH, but the risk of gastrointestinal bleeding is higher with DOACs than with LMWH in patients with gastrointestinal cancer.