Pulmonary Embolism Guidelines

Updated: Jun 27, 2017
  • Author: Daniel R Ouellette, MD, FCCP; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Guidelines

Guidelines Summary

Guidelines for the diagnosis and management of pulmonary embolism (PE) have been issued by the following organizations:

  • American Academy of Family Physicians (AAFP)/American College of Physicians (ACP) [4]
  • American College of Physicians (ACP) [107]
  • American College of Emergency Physicians (ACEP) [108]
  • American College of Radiology (ACR) [69]
  • American College of Chest Physicians [5, 109]
  • American Heart Association (AHA) [102]
  • American College of Obstetricians and Gynecologists (ACOG) [110]
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Clinical Scoring Guidelines

A 2007 clinical practice guideline from the American Academy of Family Physicians (AAFP) and the American College of Physicians (ACP) recommends that validated clinical prediction rules be used to estimate pretest probability of pulmonary embolism (PE) and to interpret test results. [4] The guideline, Current Diagnosis of Venous Thromboembolism in Primary Care, advocates use of the Wells prediction rule for this purpose but notes that the Wells rule performs better in younger patients without comorbidities or a history of venous thromboembolism (VTE) than in other patients.

In 2015, the ACP released guidelines for the evaluation of patients with suspected acute PE, which included the following recommendations [107] :

  • Plasma D-dimer tests are more appropriate for those at intermediate risk for a PE, and no testing may be necessary for some patients at low risk.
  • Use either the Wells or Geneva rules to choose tests based on a patient's risk for PE.
  • If the patient is at low risk, clinicians should use the eight Pulmonary Embolism Rule-Out Criteria (PERC); if a patient meets all eight criteria, the risks of testing are greater than the risk for embolism, and no testing is needed.
  • For patients at intermediate risk, or for those at low risk who do not meet all of the rule-out criteria, use a high-sensitivity plasma D-dimer test as the initial test.
  • In patients older than 50 years, use an age-adjusted threshold (age × 10 ng/mL, rather than a blanket 500 ng/mL), because normal D-dimer levels increase with age.
  • Patients with a D-dimer level below the age-adjusted cutoff should not receive any imaging studies.
  • Patients with elevated D-dimer levels should then receive imaging.
  • Patients at high risk should skip the D-dimer test and proceed to CT pulmonary angiography, because a negative D-dimer test does not eliminate the need for imaging in these patients.
  • Clinicians should only obtain ventilation-perfusion scans in patients with a contraindication to CT pulmonary angiography or if CT pulmonary angiography is unavailable.
  • Clinicians should use validated clinical prediction rules to estimate pretest probability in patients in whom acute PE is being considered.

In contrast, the 2011 guidelines of the American College of Emergency Physicians (ACEP) find that either objective criteria or gestalt clinical assessment can be used to risk-stratify patients with suspected PE. There is insufficient evidence to support the preferential use of one method over another (level B). For patients with a low pretest probability for suspected PE, PERC may be used to exclude the diagnosis based on historical and physical examination data alone (level B). Other key recommendations include the following [108] :

  • Negative quantitative D-dimer assay results can be used to exclude PE in patients with a low pretest probability for PE (level A).
  • Negative quantitative D-dimer assay results may be used to exclude PE in patients with an intermediate pretest probability for PE (level C).
  • For patients with a low or PE unlikely (Wells score 4) pretest probability for PE who require additional diagnostic testing (eg, positive D-dimer result, or highly sensitive D-dimer test not available), a negative, multidetector CT pulmonary angiogram alone can be used to exclude PE (level B).
  • For patients with an intermediate or high pretest probability for PE and a negative CT pulmonary angiogram result in whom a clinical concern for PE still exists and CT venogram has not already been performed, consider additional diagnostic testing (eg, D-dimer, lower extremity imaging, VQ scanning, traditional pulmonary arteriography) prior to exclusion of VTE disease (level C).
  • Venous ultrasound may be considered as initial imaging in patients with obvious signs of deep venous thrombosis (DVT) for whom venous ultrasound is readily available, patients with relative contraindications for CT scan (eg, borderline renal insufficiency, CT contrast agent allergy), and pregnant patients. A positive finding in a patient with symptoms consistent with PE can be considered evidence for diagnosis of VTE disease and may preclude the need for additional diagnostic imaging in the emergency department (level B).
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Imaging Guidelines

In its 2011 guidelines, the American College of Radiology (ACR) considers

multislice CT pulmonary angiography to be the standard of care for the detection of pulmonary embolism (PE). Additional recommendation include the following [69] :

  • A chest radiograph cannot exclude or confirm PE, but it is important (as a complementary study) as it can guide further investigations and suggest alternative diagnoses.
  • Any test that can confirm either deep venous thrombosis (DVT) (ie, lower-extremity venous duplex) or PE is sufficient. Only certain studies, however, have sufficient accuracy to exclude PE.
  • Ventilation/perfusion (V/Q) scanning appears to have high overall accuracy.
  • In pregnancy, with radiation a particular concern, the choice between perfusion scanning and CT pulmonary angiography depends on local equipment and expertise, as well as patient factors (normal chest radiograph, ability to breathhold).
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Antithrombotic and Thrombolytic Therapy Guidelines

In 2016, the American College of Chest Physicians (ACCP) updated recommendations on 12 topics that were in the 9th edition of their Antithrombotic Therapy for VTE Disease: Antithrombotic Therapy and Prevention of Thrombosis guidelines, and address three new topics. [109]

Key new or revised recommendations include the following:

  • Dabigatran, rivaroxaban, apixaban, or edoxaban are preferred over vitamin K antagonist (VKA) therapy as long-term (first 3 months) anticoagulant therapy for noncancer patients (all grade 2B).
  • Low-molecular-weight heparin (LMWH) is recommended over VKA therapy, dabigatran, rivaroxaban, apixaban, or edoxaban as long-term (first 3 months) anticoagulant therapy for patients with cancer-associated thrombosis (all grade 2C).
  • Aspirin is recommended over no aspirin to prevent recurrent venous thromboembolism (VTE) in patients who are stopping anticoagulant therapy and do not have a contraindication to aspirin (grade 2B).
  • In most patients with acute pulmonary embolism (PE) not associated with hypotension, systemically administered thrombolytic therapy is recommended against (grade 1B).
  • In selected patients with acute PE who deteriorate after starting anticoagulant therapy but have yet to develop hypotension and who have a low bleeding risk, systemically administered thrombolytic therapy is preferred over no such therapy (grade 2C).

According to ACCP 9th edition guidelines, immediate therapeutic anticoagulation should be initiated for patients in whom deep venous thrombosis (DVT) or PE (grade 1B) is suspected. [5] Anticoagulation therapy reduces mortality rates from 30% to less than 10%. Diagnostic investigations should not delay empirical anticoagulant therapy in patients with high or intermediate risk of PE (grade 2C).

For acute PE, the ACCP guidelines recommend starting LMWH or fondaparinux, preferred over unfractionated heparin (UFH) (grade 2C for LMWH; grade 2B for fondaparinux) or subcutaneous heparin (grade 2B for LMWH; grade 2C for fondaparinux). [5] If patients are to be treated with LMWH, once-daily treatment is preferred to twice-daily treatment (grade 2C).

Patients who are considered to be low risk should be discharged early from hospital (grade 2B).

Patients should have an oral anticoagulant (warfarin) initiated at the time of diagnosis, and they should have UFH, LMWH, or fondaparinux discontinued only after the international normalized ratio (INR) is 2.0 for at least 24 hours but no sooner than 5 days after warfarin therapy has been started (grade 1B). The recommended duration of UFH, LMWH, and fondaparinux is based on evidence suggesting that the relatively long half-life of factor II, along with the short half-lives of protein C and protein S, may provoke a paradoxical hypercoagulable state if these agents are discontinued prematurely.

The ACCP guidelines for antithrombotic and thrombolytic therapy are summarized as follows [5] :

  • Thrombolytic therapy should be used in patients with acute PE associated with hypotension (systolic BP <90 mm Hg), who do not have a high bleeding risk (grade 2C).
  • Thrombolytic therapy is suggested in select patients with acute PE not associated with hypotension and with a low bleeding risk whose initial clinical presentation or clinical course after starting anticoagulation suggests a high risk of developing hypotension (grade 2C).
  • Assessment of PE severity, prognosis, and risk of bleeding dictates whether thrombolytic therapy should be started. Thrombolytic therapy is not recommended for most patients with acute PE not associated with hypotension (grade 1C).
  • All patients with unprovoked PE receive 3 months of treatment with anticoagulation rather than a shorter duration of treatment, and they have an assessment of the risk-to-benefit ratio of extended therapy at the end of 3 months (grade 1B).
  • Patients with a first episode of VTE and with a low or moderate risk of bleeding should have extended anticoagulant therapy (grade 2B). Patients with a first episode of VTE who have a high bleeding risk should have therapy limited to 3 months (grade 1B). In patients with a second unprovoked episode of VTE and low or moderate risk of bleeding, extended anticoagulant therapy is recommended (grades 1B and 2B, respectively). In patients with a second episode of VTE and a high risk of bleeding, 3 months of anticoagulation is preferred rather than extended anticoagulation (grade 2B).
  • Patients who have PE and preexisting irreversible risk factors, such as deficiency of antithrombin III, proteins S and C, factor V Leiden mutation, or the presence of antiphospholipid antibodies, should be placed on long-term anticoagulation.
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Guidelines on Advanced Therapies for Acute VTE

In 2011, guidelines to help emergency department and other physicians determine which patients with venous thromboembolism (VTE) should receive advanced therapies rather than simple anticoagulation were issued by the American Heart Association (AHA). [102] Recommendations for management of acute pulmonary embolism (PE) are as follows:

  • Therapeutic anticoagulation with subcutaneous low-molecular-weight heparin (LMWH), intravenous or subcutaneous unfractionated heparin (UFH) with monitoring, unmonitored weight-based subcutaneous UFH, or subcutaneous fondaparinux should be given to patients with objectively confirmed PE and no contraindications to anticoagulation (class I).
  • Therapeutic anticoagulation during the diagnostic workup should be given to patients with intermediate or high clinical probability of PE and no contraindications to anticoagulation (class I).
  • Fibrinolysis is reasonable for patients with massive acute PE and acceptable risk of bleeding complications (class IIa).
  • Fibrinolysis may be considered for patients with submassive acute PE judged to have clinical evidence of adverse prognosis (new hemodynamic instability, worsening respiratory insufficiency, severe right ventricular dysfunction, or major myocardial necrosis) and low risk of bleeding complications (class IIb).
  • Fibrinolysis is not recommended for the following patients(class III): (1) Low-risk PE; (2) Submassive acute PE with minor right ventricular dysfunction, minor myocardial necrosis, and no clinical worsening; and (3) With undifferentiated cardiac arrest.

Recommendations for catheter-based interventions include the following:

  • For patients with massive PE and contraindications to fibrinolysis, catheter embolectomy and fragmentation or surgical embolectomy is reasonable, depending on the expertise available (class IIa).
  • For patients with massive PE who remain unstable after receiving fibrinolysis, catheter embolectomy and fragmentation or surgical embolectomy is reasonable (class IIa).
  • For patients with massive PE who cannot receive fibrinolysis or who remain unstable after fibrinolysis, consider transfer to an institution experienced in either catheter embolectomy or surgical embolectomy if these procedures are not available and safe transfer can be achieved (class IIa).
  • Either catheter embolectomy or surgical embolectomy may be considered for patients with submassive acute PE judged to have clinical evidence of adverse prognosis (new hemodynamic instability, worsening respiratory failure, severe right ventricular dysfunction, or major myocardial necrosis) (class IIb).
  • Catheter embolectomy and surgical thrombectomy are not recommended for patients with low-risk PE or submassive acute PE with minor right ventricular dysfunction, minor myocardial necrosis, and no clinical worsening (class III).

Recommendations for use of vena cava filters include the following:

  • Patients with confirmed acute PE (or proximal deep venous thrombosis [DVT]) with contraindications to anticoagulation or with active bleeding complications should receive an inferior vena cava (IVC) filter (class I).
  • Anticoagulation should be resumed in patients with an IVC filter once contraindications to anticoagulation or active bleeding complications have resolved (class I).
  • Patients who receive retrievable IVC filters should be evaluated periodically for filter retrieval within the specific filter’s retrieval window (class I).
  • Placement of an IVC filter is reasonable for patients with recurrent acute PE despite therapeutic anticoagulation (class IIa).
  • A permanent IVC filter device is reasonable for patients with a long-term contraindication to anticoagulation (class IIa).
  • A retrievable IVC filter device is reasonable for patients with a short-term contraindication to anticoagulation therapy (class IIa).
  • Placement of an IVC filter may be considered for patients with acute PE and very poor cardiopulmonary reserve, including those with massive PE (class IIb).
  • An IVC filter should not be used routinely as an adjuvant to anticoagulation and systemic fibrinolysis in the treatment of acute PE (class III).
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Pregnancy and Gynecological Surgery Guidelines

In 2011, the American College of Obstetricians and Gynecologists (ACOG) published a practice bulletin on the diagnosis, management, and prevention of thromboembolism during pregnancy. The key recommendations included the following [110] :

  • Compression ultrasonography of the proximal veins is the recommended initial diagnostic test when signs or symptoms suggest new-onset deep veinous thrombosis (DVT) (level A).
  • Women with a history of thrombosis who have not been thoroughly evaluated for possible underlying causes should receive testing for antiphospholipid antibodies, as well as for inherited thrombophilias (level C).
  • Heparin compounds are preferred for anticoagulation (level B).
  • Anticoagulation is recommended for women with acute thromboembolism during the current pregnancy or those at high risk of venous thromboembolism (VTE), such as women with mechanical heart valves (level C).
  • In the last month of pregnancy, or sooner if delivery appears imminent, women receiving either therapeutic or prophylactic anticoagulation may be converted from low-molecular-weight heparin (LMWH) to unfractionated heparin (UFH), which has a shorter half-life (level C).
  • Neuraxial blockade should be withheld for 10-12 hours after the last prophylactic dose of LMWH or 24 hours after the last therapeutic dose of LMWH (level C).
  • For all women not already receiving thromboprophylaxis, placement of pneumatic compression devices before cesarean delivery is recommended. However, an emergency cesarean delivery should not be delayed for the placement of compression devices (level C).
  • To minimize postpartum bleeding complications, a reasonable strategy is to resume anticoagulation therapy no sooner than 4-6 hours after vaginal delivery or 6-12 hours after cesarean delivery (level B).
  • For women in whom restarting anticoagulation is planned after delivery, pneumatic compression devices should be left in place until the woman is ambulatory and anticoagulation therapy is resumed (level C).
  • Warfarin, LMWH, and UFH are compatible with breastfeeding because they do not accumulate in breast milk and do not lead to anticoagulation in the infant (level B).
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