Treatment of Bilateral Pulmonary Embolism
For bilateral pulmonary embolism, immediate anticoagulation therapy is the cornerstone of treatment, with the specific regimen determined by risk stratification, and NOACs are preferred over vitamin K antagonists for non-high-risk patients without contraindications. 1
Risk Stratification
Risk stratification is the first critical step in managing bilateral PE and determines the treatment approach:
High-risk PE (hemodynamically unstable):
- Systolic BP <90 mmHg or drop ≥40 mmHg for >15 minutes
- Signs of shock: tachycardia, altered mental status, cool extremities
Intermediate-risk PE (hemodynamically stable with RV dysfunction/myocardial injury)
Low-risk PE (hemodynamically stable without RV dysfunction/myocardial injury)
Treatment Algorithm Based on Risk
High-Risk PE (Hemodynamically Unstable)
- Immediate anticoagulation: Unfractionated heparin (UFH) IV bolus (80 units/kg) followed by continuous infusion (18 units/kg/hour) 2
- Systemic thrombolytic therapy (Class I recommendation) unless contraindicated 2
- Vasopressors (norepinephrine and/or dobutamine) for hemodynamic support 2
- Oxygen therapy for hypoxemia 2
- Surgical pulmonary embolectomy if thrombolysis is absolutely contraindicated or has failed 2
- Catheter embolectomy or fragmentation may be considered as an alternative when thrombolysis is contraindicated or has failed 2
Non-High-Risk PE (Hemodynamically Stable)
- Immediate anticoagulation without delay 2
- Preferred initial treatment: LMWH or fondaparinux over UFH 2
- Oral anticoagulation: NOACs (apixaban, dabigatran, edoxaban, or rivaroxaban) preferred over VKA 2
- If using VKA: Overlap with parenteral anticoagulation until INR 2.0-3.0 is reached for at least 2 consecutive days 2
Specific Anticoagulation Regimens
Initial Parenteral Anticoagulation
LMWH (preferred for most patients):
- Weight-adjusted dosing (e.g., enoxaparin 1 mg/kg twice daily)
- Continue for at least 5 days and until adequate oral anticoagulation is established 2
UFH (preferred in severe renal dysfunction or if thrombolysis is being considered):
- IV bolus of 80 U/kg followed by infusion at 18 U/kg/hour
- Adjust dose to maintain aPTT at 1.5-2.5 times control 2
Oral Anticoagulation
NOACs (preferred option):
VKA (alternative if NOACs contraindicated):
- Overlap with parenteral anticoagulation
- Target INR 2.0-3.0
- Continue parenteral anticoagulation until INR ≥2.0 for at least 2 consecutive days 2
Duration of Anticoagulation
- First episode with major transient/reversible risk factor: 3 months 2
- Unprovoked PE or ongoing risk factors: Extended anticoagulation (>3 months) 2
- Recurrent VTE: Indefinite anticoagulation 2
Special Considerations
Renal Dysfunction
- Severe renal impairment (CrCl <30 ml/min):
- Use UFH followed by VKA
- Avoid NOACs 1
Cancer-Associated PE
- LMWH preferred over VKA or NOACs for at least 6 months
- Continue treatment as long as cancer is active 2
Pregnancy
- LMWH is the treatment of choice
- Fixed doses based on early pregnancy weight
- Do not use NOACs during pregnancy or lactation 2
Follow-up Care
- Routinely re-evaluate patients 3-6 months after acute PE 2
- Assess for signs of post-thrombotic syndrome or chronic thromboembolic pulmonary hypertension
- For extended anticoagulation, regularly reassess drug tolerance, adherence, renal/hepatic function, and bleeding risk 2
Common Pitfalls to Avoid
- Delaying anticoagulation when clinical suspicion is high
- Aggressive fluid administration (can worsen RV failure)
- Routine use of IVC filters (not recommended unless specific indications exist)
- Failing to assess renal function before selecting anticoagulant
- Not monitoring for heparin-induced thrombocytopenia 1