What is the treatment for pulmonary embolism?

Treatment of Pulmonary Embolism

For patients with pulmonary embolism, non-vitamin K antagonist oral anticoagulants (NOACs) such as apixaban, dabigatran, edoxaban, or rivaroxaban are the preferred first-line treatment over traditional heparin-vitamin K antagonist regimens, unless contraindicated. 1

Diagnosis and Risk Stratification

Initial Assessment

• Stratify patients based on hemodynamic stability to identify those at high risk of early mortality
• For suspected PE with hemodynamic instability, perform bedside echocardiography as an immediate step
• For stable patients, use validated diagnostic algorithms including:
  • Clinical probability assessment
  • D-dimer testing (in low/intermediate probability cases)
  • Appropriate imaging

Imaging Recommendations

• CTPA is the recommended initial lung imaging for non-massive PE 1
• Normal perfusion lung scan reliably excludes PE
• Accept PE diagnosis if CTPA shows segmental or more proximal filling defect in patients with intermediate/high clinical probability

Treatment Algorithm

1. High-Risk PE (with hemodynamic instability - systolic BP <90 mmHg)

• Initiate intravenous unfractionated heparin (UFH) immediately, including weight-adjusted bolus 1
• Administer systemic thrombolytic therapy (Class I recommendation) 1
  • 50 mg bolus of alteplase for cardiac arrest or imminent collapse 1
  • For confirmed massive PE with stability for imaging, 100 mg alteplase over 90 minutes 1
• Consider surgical pulmonary embolectomy when thrombolysis is contraindicated or has failed 1

2. Non-High-Risk PE (hemodynamically stable)

• Initiate anticoagulation promptly if clinical probability is intermediate or high, while diagnostic workup progresses 1
• For initial anticoagulation:
  • Prefer LMWH or fondaparinux over UFH in stable patients 1
  • When oral anticoagulation is initiated, prefer a NOAC (apixaban, dabigatran, edoxaban, or rivaroxaban) if eligible 1
  • If using vitamin K antagonist (VKA), overlap with parenteral anticoagulation until INR of 2.0-3.0 is reached 1

Duration of Anticoagulation

• All patients should receive therapeutic anticoagulation for >3 months 1
• After initial 3-6 months, assess for extended therapy:
  • Discontinue after 3 months for first PE secondary to a major transient/reversible risk factor 1
  • Continue indefinitely for recurrent VTE not related to a major transient/reversible risk factor 1
  • Continue indefinitely with VKA for patients with antiphospholipid antibody syndrome 1

Special Considerations

Pregnancy

• Use therapeutic, fixed doses of LMWH based on early pregnancy weight 1
• Do not use NOACs during pregnancy or lactation 1
• Do not insert spinal/epidural needle within 24h of last LMWH dose 1

Contraindications to NOACs

• Severe renal impairment
• Antiphospholipid antibody syndrome 1

Follow-up Care

• Routinely re-evaluate patients 3-6 months after acute PE 1
• For extended anticoagulation, regularly reassess drug tolerance, adherence, hepatic and renal function, and bleeding risk 1
• Refer symptomatic patients with mismatched perfusion defects beyond 3 months to a pulmonary hypertension/CTEPH expert center 1

Common Pitfalls to Avoid

• Do not measure D-dimers in patients with high clinical probability, as a normal result does not safely exclude PE 1
• Do not routinely administer systemic thrombolysis for intermediate or low-risk PE 1
• Do not routinely use inferior vena cava filters 1
• Do not use NOACs in patients with severe renal impairment or antiphospholipid antibody syndrome 1
• Do not lose patients to follow-up after acute PE - implement an integrated model of care for transition from hospital to ambulatory care 1

Resolution Timeline

• Clinical improvement often occurs within 24-72 hours for symptoms like dyspnea and chest pain
• Significant reduction in respiratory symptoms typically occurs within 1-2 weeks
• Most clinical symptoms resolve within 1-3 months 2
• Pulmonary emboli gradually dissolve over weeks to months, with complete resolution in 50-80% of patients 2