How should pulmonary embolism be managed?

Management of Pulmonary Embolism

Immediate Risk Stratification

The first critical step is determining hemodynamic stability: patients with shock or sustained hypotension (systolic blood pressure <90 mmHg) require immediate aggressive treatment, while hemodynamically stable patients receive standard anticoagulation. 1, 2

High-Risk PE (Hemodynamically Unstable)

Massive PE is highly likely when you observe the combination of:

• Collapse or sustained hypotension
• Unexplained hypoxia
• Engorged neck veins
• Right ventricular gallop 1, 3

For hemodynamically unstable patients, initiate unfractionated heparin immediately (80 units/kg IV bolus or 5,000-10,000 units bolus) without waiting for imaging confirmation. 1, 3, 2

Thrombolysis Protocols

Administer systemic thrombolysis immediately to all hemodynamically unstable PE patients who lack high bleeding risk—this is life-saving and should not be delayed. 3, 2

Specific thrombolysis regimens:

• Cardiac arrest: Begin CPR and give alteplase 50 mg IV bolus during resuscitation 1, 3
• Deteriorating patients: Contact senior consultant immediately and give alteplase 50 mg IV bolus 1, 3
• Stable patients with confirmed massive PE: Alteplase 100 mg IV over 90 minutes 1, 3, 2

Critical caveat: Contraindications to thrombolysis should be ignored in life-threatening PE, as mortality benefit outweighs bleeding risks. 1, 3

After thrombolysis, start weight-adjusted unfractionated heparin infusion 3 hours after completion, targeting aPTT 1.5-2.5 times control. 1, 3, 2

Alternative Reperfusion Strategies

If thrombolysis is absolutely contraindicated or fails, surgical pulmonary embolectomy is the preferred alternative. 3, 2

Catheter-directed treatment or ECMO may be considered for refractory cases, though evidence is limited. 1, 3, 2

Intermediate-Risk PE (Hemodynamically Stable)

For stable patients, use validated risk scores (PESI class I/II, sPESI 0, or Hestia criteria) to identify low-risk patients suitable for outpatient management. 1

Exclusion criteria for outpatient management include:

• Heart rate >110 bpm or SBP <100 mmHg
• Oxygen saturation <90% on room air
• Active bleeding or high bleeding risk
• Severe pain requiring opiates
• CKD stage 4-5 (eGFR <30 mL/min) or severe liver disease
• Social factors preventing safe home care 1

Anticoagulation Strategy

When initiating oral anticoagulation in PE patients eligible for a NOAC (apixaban, dabigatran, edoxaban, or rivaroxaban), a NOAC is the recommended form of treatment over warfarin. 1, 4

Rivaroxaban dosing for PE treatment: 15 mg twice daily with food for 21 days, then 20 mg once daily with food. 4

Duration of Anticoagulation

Minimum duration is 3 months for all PE cases. 1, 2

Extended anticoagulation (beyond 3 months) should be considered for:

• Unprovoked PE with low-to-moderate bleeding risk 1, 2
• Persistent risk factors other than antiphospholipid syndrome 1
• Minor transient/reversible risk factors 1

After 6 months, consider reduced-dose apixaban or rivaroxaban for extended treatment. 1

Indefinite anticoagulation is mandatory for:

• Antiphospholipid antibody syndrome (use VKA, not NOAC) 1
• Recurrent VTE (≥1 previous episode) unrelated to major transient risk factors 2

Post-PE Care

Routine clinical evaluation is mandatory at 3-6 months after acute PE to assess for chronic thromboembolic pulmonary hypertension (CTEPH). 1, 2

Refer symptomatic patients with mismatched perfusion defects on V/Q scan >3 months post-PE to a pulmonary hypertension expert center. 1, 2

Common Pitfalls

Avoid aggressive fluid resuscitation in massive PE—this worsens right ventricular failure. 2

Do not delay thrombolysis to obtain imaging in unstable patients; bedside echocardiography showing RV overload is sufficient to justify treatment. 5, 2

Premature discontinuation of anticoagulation increases thrombotic event risk—if stopping for reasons other than bleeding, provide bridging with alternative anticoagulation. 4