What is the treatment for pulmonary embolism?

Treatment of Pulmonary Embolism

For patients with pulmonary embolism, initiate anticoagulation immediately with risk stratification guiding the intensity of treatment: high-risk PE requires systemic thrombolysis, intermediate-risk PE requires anticoagulation with consideration for escalation, and low-risk PE requires anticoagulation alone with potential for early discharge. 1, 2

Risk Stratification Framework

Risk stratification must be performed immediately to determine treatment intensity 1, 2:

• High-risk PE: Presence of shock or sustained hypotension (systolic BP <90 mmHg for ≥15 minutes or requiring vasopressor support) 2
• Intermediate-risk PE: Hemodynamically stable but with evidence of right ventricular dysfunction on imaging or elevated cardiac biomarkers 2
• Low-risk PE: Hemodynamically stable without right ventricular dysfunction 2

Assessment of right ventricular function by imaging or laboratory biomarkers should be performed even in patients with low PESI or sPESI of 0 1

Acute Management by Risk Category

High-Risk PE (Hemodynamically Unstable)

Immediate interventions required 2:

• Anticoagulation: Administer unfractionated heparin (UFH) immediately with weight-adjusted bolus of 80 U/kg or 5,000-10,000 units, followed by continuous infusion of 18 U/kg/h, adjusted to maintain aPTT 1.5-2.5 times control 2
• Systemic thrombolytic therapy: Administer unless contraindicated—this is now a Class I recommendation (upgraded from Class IIa in 2014) 1, 2
• Rescue thrombolysis: For patients who deteriorate hemodynamically despite initial treatment 1
• Surgical embolectomy or catheter-directed treatment: Consider as alternatives to rescue thrombolytic therapy if thrombolysis is contraindicated or fails (upgraded to Class IIa recommendation) 1, 2
• ECMO: May be considered in combination with surgical embolectomy or catheter-directed treatment in refractory circulatory collapse or cardiac arrest 1

Hemodynamic support 3, 2:

• Administer supplemental oxygen for SaO2 <90%, escalating delivery methods as needed 3
• Use vasopressors (norepinephrine and/or dobutamine) to correct hypotension 3, 2
• Avoid aggressive fluid challenges—this may worsen right ventricular failure 3

Common pitfall: Positive pressure ventilation from invasive mechanical ventilation may worsen right ventricular failure; reserve intubation for extreme instability only 3

Intermediate-Risk PE (Hemodynamically Stable with RV Dysfunction)

• Initiate anticoagulation with low molecular weight heparin (LMWH) or fondaparinux, which is preferred over UFH 2
• Set up multidisciplinary teams for management of selected intermediate-risk cases depending on available resources 1
• Thrombolysis may be considered in patients with clinical deterioration 4
• Monitor closely for hemodynamic deterioration that would warrant escalation to thrombolytic therapy 3

Low-Risk PE (Hemodynamically Stable without RV Dysfunction)

• Initiate anticoagulation with LMWH or fondaparinux preferred over UFH 2
• Consider early discharge and home treatment for carefully selected patients with proper outpatient care arrangements 2

Anticoagulation Protocol

Initial Anticoagulation Selection

When oral anticoagulation is initiated in a patient with PE who is eligible for a NOAC (apixaban, dabigatran, edoxaban, or rivaroxaban), a NOAC is the recommended form of anticoagulant treatment (Class I recommendation) 1:

• Rivaroxaban: FDA-approved for treatment of PE 5
• Apixaban: FDA-approved for treatment of PE 6

NOACs are contraindicated in 2:

• Severe renal impairment
• Pregnancy and lactation
• Antiphospholipid antibody syndrome

Duration of Anticoagulation

Extended anticoagulation strategy 1:

• Indefinite treatment with vitamin K antagonist: Required for patients with antiphospholipid antibody syndrome (Class I recommendation) 1
• Extended anticoagulation should be considered for: 1
  • Patients with no identifiable risk factor (unprovoked PE)
  • Patients with persistent risk factors other than antiphospholipid antibody syndrome
  • Patients with minor transient/reversible risk factors
• Reduced dose: After the first 6 months, a reduced dose of apixaban or rivaroxaban should be considered 1

Discontinue anticoagulation: After initial 3-6 months in patients whose first episode was associated with temporary risk factors 7

Special Populations

Cancer-Associated PE

Edoxaban or rivaroxaban should be considered as an alternative to LMWH, except in patients with gastrointestinal cancer 1

Pregnancy

• NOACs are not recommended during pregnancy or lactation 1, 2
• Thrombolysis or surgical embolectomy should be considered for pregnant women with high-risk PE 1
• D-dimer measurement and clinical prediction rules should be considered to rule out PE during pregnancy or post-partum period 1

Management of Refractory Hypoxemia

Escalation pathway for oxygen delivery 3:

1. Conventional supplemental oxygen for SaO2 <90%
2. High-flow oxygen via nasal cannula if conventional oxygen insufficient
3. Non-invasive ventilation if high-flow oxygen insufficient
4. Invasive mechanical ventilation only for extreme instability

If intubation necessary 3:

• Use tidal volumes approximately 6 mL/kg lean body weight
• Keep end-inspiratory plateau pressure <30 cm H2O
• Apply positive end-expiratory pressure cautiously
• Avoid anesthetic drugs causing hypotension

Common pitfall: Overlooking right-to-left shunting through patent foramen ovale as a cause of refractory hypoxemia 3

Inferior Vena Cava Filters

Consider IVC filters only in patients with absolute contraindications to anticoagulation or PE recurrence despite therapeutic anticoagulation 2

Post-PE Care and Long-Term Follow-Up

Mandatory follow-up protocol 1:

• Routine clinical evaluation at 3-6 months after acute PE (Class I recommendation) 1
• Implement integrated model of care to ensure optimal transition from hospital to ambulatory care (Class I recommendation) 1
• Refer symptomatic patients with mismatched perfusion defects on V/Q scan >3 months after acute PE to pulmonary hypertension/CTEPH expert center, considering echocardiography, natriuretic peptide, and/or cardiopulmonary exercise testing results (Class I recommendation) 1