What is the guideline for treating pulmonary embolism?

Guideline for Treating Pulmonary Embolism

Initiate anticoagulation immediately without delay in all patients with suspected pulmonary embolism while diagnostic workup is in progress, unless absolute contraindications exist. 1

Risk Stratification Determines Treatment Intensity

Risk stratification based on hemodynamic stability is the critical first step that determines treatment intensity 1:

• High-risk PE: Systolic blood pressure <90 mmHg, need for vasopressors, or shock 1
• Intermediate-risk PE: Hemodynamically stable but with right ventricular dysfunction or myocardial injury 1
• Low-risk PE: Hemodynamically stable without right ventricular dysfunction 1

Treatment Algorithm by Risk Category

High-Risk PE (Hemodynamically Unstable)

Systemic thrombolytic therapy is the first-line treatment for high-risk PE (Class I, Level B recommendation). 1

Immediate management includes:

• Unfractionated heparin with weight-adjusted bolus (80 U/kg bolus, then 18 U/kg/h infusion) initiated immediately 2, 1
• Norepinephrine and/or dobutamine for hemodynamic support (avoid aggressive fluid challenges as they worsen right ventricular failure) 1, 3
• Surgical pulmonary embolectomy if thrombolysis is contraindicated or fails (Class I, Level C recommendation) 1
• Percutaneous catheter-directed treatment as an alternative (Class IIa, Level C recommendation) 1

UFH dosing adjustments based on aPTT: 2

• aPTT <35 seconds: 80 U/kg bolus; increase infusion by 4 U/kg/h
• aPTT 35-45 seconds: 40 U/kg bolus; increase infusion by 2 U/kg/h
• aPTT 46-70 seconds: No change
• aPTT 71-90 seconds: Reduce infusion by 2 U/kg/h
• aPTT >90 seconds: Stop infusion for 1 hour, then reduce by 3 U/kg/h

Intermediate-Risk and Low-Risk PE (Hemodynamically Stable)

For hemodynamically stable patients, direct oral anticoagulants (DOACs) are recommended over vitamin K antagonists (Class I, Level A recommendation). 1

Parenteral anticoagulation options (Class I, Level A recommendation): 1

• Low molecular weight heparin (LMWH) or fondaparinux is preferred over unfractionated heparin 1
• Enoxaparin 1.0 mg/kg every 12 hours OR 1.5 mg/kg once daily 2
• Tinzaparin 175 U/kg once daily 2
• Fondaparinux: 5 mg (weight <50 kg), 7.5 mg (50-100 kg), or 10 mg (>100 kg) once daily 2

Oral anticoagulation options: 1, 4

• Rivaroxaban 15 mg twice daily with food for 21 days, then 20 mg once daily with food 4
• Dabigatran or edoxaban (after 5-10 days of parenteral anticoagulation) 1
• If VKA is used, overlap with parenteral anticoagulation until INR reaches 2.5 (range 2.0-3.0) for at least 4-5 days 2, 1

Duration of Anticoagulation

All patients require therapeutic anticoagulation for a minimum of 3 months. 1

Duration decisions: 2, 1

• Discontinue after 3 months if first PE was provoked by a major transient/reversible risk factor
• Continue indefinitely if recurrent venous thromboembolism (at least one previous episode) not related to a major transient risk factor
• Continue indefinitely with VKA (not DOACs) in patients with antiphospholipid antibody syndrome 2, 1

Special Populations and Contraindications

DOACs are contraindicated in: 1

• Severe renal impairment (CrCl <15 mL/min for rivaroxaban) 4
• Pregnancy and lactation 2
• Antiphospholipid syndrome 1

For pregnant patients: 2

• Use therapeutic fixed doses of LMWH based on early pregnancy weight
• Do not insert spinal/epidural needle within 24 hours of last LMWH dose
• Do not administer LMWH within 4 hours of epidural catheter removal

Inferior Vena Cava Filters

IVC filters should be considered only in acute PE with absolute contraindications to anticoagulation (Class IIa, Level C recommendation). 1

Routine use of IVC filters is not recommended (Class III, Level A recommendation). 1

Critical Pitfalls to Avoid

• Never delay anticoagulation while awaiting diagnostic confirmation in patients with high clinical suspicion 2, 1
• Avoid aggressive fluid challenges in hemodynamically unstable PE as positive pressure worsens right ventricular failure 3
• Monitor platelet count during unfractionated or low molecular weight heparin therapy due to risk of heparin-induced thrombocytopenia 2
• Do not use positive pressure ventilation prematurely as it may worsen right ventricular failure; reserve invasive mechanical ventilation for extreme instability 3

Follow-Up Care

Routinely re-evaluate all patients 3-6 months after acute PE to assess for chronic thromboembolic pulmonary hypertension and persistent symptoms. 2, 1

Refer symptomatic patients with mismatched perfusion defects on V/Q scan beyond 3 months to a pulmonary hypertension/CTEPH expert center. 2