Treatment of Pulmonary Embolism
The treatment of pulmonary embolism should begin with risk stratification based on hemodynamic stability, followed by appropriate anticoagulation therapy, with direct oral anticoagulants (DOACs) being the preferred first-line treatment for eligible patients with non-massive PE. 1, 2
Initial Risk Stratification
Patients with PE should be immediately classified based on hemodynamic stability to guide treatment approach 1, 2:
- High-risk (massive) PE: Hemodynamic instability (systolic BP <90 mmHg)
- Intermediate-risk PE: Hemodynamically stable with right ventricular dysfunction
- Low-risk PE: Hemodynamically stable without right ventricular dysfunction
Assessment of right ventricular function using imaging (echocardiography or CT) or laboratory biomarkers should be performed even in patients with low clinical risk scores 1, 2
Treatment Approach Based on Risk Category
High-Risk (Massive) PE
Systemic thrombolytic therapy is the first-line treatment for patients with high-risk PE presenting with hemodynamic instability 1
Consider surgical embolectomy or catheter-directed treatment as alternatives when thrombolysis fails or is contraindicated 1
Extracorporeal membrane oxygenation (ECMO) may be considered in combination with surgical embolectomy or catheter-directed treatment for patients with refractory circulatory collapse or cardiac arrest 1, 3
Initiate intravenous unfractionated heparin without delay, including a weight-adjusted bolus 2
Intermediate and Low-Risk PE
For non-high-risk PE patients, direct oral anticoagulants (DOACs) are the preferred treatment option when eligible 1, 2:
If parenteral anticoagulation is initiated, low-molecular-weight heparin (LMWH) is preferred over unfractionated heparin for patients without hemodynamic instability 2
Thrombolysis is not recommended as first-line treatment for non-massive PE 1
Duration of Anticoagulation
All patients with PE should receive therapeutic anticoagulation for at least 3 months 2
Consider extended anticoagulation in the following scenarios 1, 2:
- Indefinite treatment with vitamin K antagonist for patients with antiphospholipid antibody syndrome
- Extended treatment for patients with no identifiable risk factor for the index PE event
- Extended treatment for patients with a persistent risk factor other than antiphospholipid syndrome
- Extended treatment for patients with a minor transient/reversible risk factor
For extended treatment beyond 6 months, consider reduced doses of apixaban or rivaroxaban 1
Discontinue therapeutic anticoagulation after 3 months in patients with a first PE episode secondary to a major transient/reversible risk factor 2
Special Populations
Cancer Patients
- Edoxaban or rivaroxaban should be considered as alternatives to LMWH, except in patients with gastrointestinal cancer 1, 2
Pregnant Women
- NOACs are contraindicated during pregnancy and lactation 1, 2
- Use fixed therapeutic doses of LMWH based on early pregnancy weight 2
- Consider thrombolysis or surgical embolectomy for pregnant women with high-risk PE 1
Follow-up Care
Routine clinical evaluation is recommended 3-6 months after acute PE 1, 2
An integrated model of care is recommended to ensure optimal transition from hospital to ambulatory care 1, 2
Refer symptomatic patients with mismatched perfusion defects on V/Q scan >3 months after acute PE to a pulmonary hypertension/CTEPH expert center 1, 2
Common Pitfalls and Caveats
Avoid delaying anticoagulation while awaiting diagnostic confirmation in patients with intermediate or high clinical probability of PE 1
Do not routinely use inferior vena cava filters; they should be reserved for patients with absolute contraindications to anticoagulation or recurrent PE despite adequate anticoagulation 3
Be aware that subsegmental PE on CT may represent false positives; consider discussing with a radiologist or seeking a second opinion before initiating potentially harmful anticoagulation 1
Remember that PE in patients with cancer may require special consideration for anticoagulant choice 1, 2