We recommend parenteral anticoagulation in patients with confirmed acute pulmonary embolism (PE), rather than no anticoagulation (Grade 1A).
In situations in which acute PE is suspected but not confirmed
We recommend parenteral anticoagulation when there is a high clinical suspicion of acute PE, rather than no anticoagulation (Grade 1B).
We suggest parenteral anticoagulation when there is a moderate clinical suspicion for acute PE and the results of the diagnostic tests are expected to take longer than four hours, rather than no anticoagulation (Grade 2C).
We suggest parenteral anticoagulation when there is a low clinical suspicion for acute PE and the results of the diagnostic tests are expected to take longer than 24 hours, rather than no anticoagulation (Grade 2C).
The clinical suspicion for acute PE should be derived using a validated prediction rule, such as the Wells criteria．
Anticoagulant therapy should be continued during the diagnostic evaluation.
The following recommendations assume that the decision has been made to initiate parenteral anticoagulant therapy:
For hemodynamically stable patients with confirmed or suspected acute PE, we recommend initial treatment with low molecular weight heparin (LMWH) rather than intravenous unfractionated heparin (IV UFH) (Grade 1B). We also suggest LMWH rather than subcutaneous fondaparinux (Grade 2C). If LMWH is not chosen, we suggest subcutaneous fondaparinux rather than IV UFH (Grade 2B).
For patients with confirmed or suspected acute PE who have persistent hypotension due to the acute PE, an increased risk of bleeding, potential abnormal subcutaneous absorption (eg, morbid obesity), or in whom thrombolysis may be performed, we suggest IV UFH rather than an alternative anticoagulant (Grade 2B).
For patients with confirmed or suspected acute PE and severe renal failure (creatinine clearance ≤30 mL/min), we suggest UFH rather than LMWH or subcutaneous fondaparinux (Grade 2B). The UFH may be administered subcutaneously or intravenously.
These recommendations assume that the patient has a low risk (no risk factors) for bleeding. In patients who have a moderate risk (one risk factor) or high risk (two or more risk factors) for bleeding, the decision to initiate anticoagulant therapy must be made on a case-by-case basis after considering the patient’s individual values and preferences. Risk factors for bleeding include age >65 years, previous bleeding, thrombocytopenia, antiplatelet therapy, poor anticoagulant control, recent surgery, frequent falls, reduced functional capacity, previous stroke, diabetes, anemia, cancer, renal failure, liver failure, and alcohol abuse.
For patients in whom anticoagulant therapy is judged to be contraindicated, the diagnostic evaluation should be expedited and placement of an inferior vena cava filter considered once an acute PE has been confirmed.