What is the initial management of pulmonary embolism (PE)?

Initial Management of Pulmonary Embolism (PE)

The initial management of pulmonary embolism should begin with risk stratification using validated clinical risk scores (PESI, sPESI, or Hestia criteria) followed by prompt anticoagulation with either low molecular weight heparin (LMWH), unfractionated heparin (UFH), or direct oral anticoagulants (DOACs) based on the patient's hemodynamic stability and risk factors. 1, 2

Risk Stratification

Risk stratification is essential to determine the appropriate treatment setting and intensity:

• Low-risk patients: PESI class I/II, sPESI 0, or meeting Hestia criteria

  • Consider for outpatient management if exclusion criteria are not present 1

• Intermediate-risk patients: Evidence of right ventricular dysfunction without hemodynamic instability

  • Typically require inpatient management and close monitoring 2

• High-risk patients: Hemodynamically unstable (systolic BP <100 mmHg, HR >110 bpm)

  • Require immediate hospitalization and consideration for thrombolysis 2

Exclusion Criteria for Outpatient Management 1

• Hemodynamic instability (HR >110 bpm, SBP <100 mmHg, need for inotropes)
• Oxygen saturation <90% on room air
• Active bleeding or high risk of major bleeding
• Already on full-dose anticoagulation at time of PE
• Severe pain requiring opiates
• Medical comorbidities requiring hospitalization
• Severe renal impairment (CKD stages 4-5, eGFR <30 mL/min)
• History of heparin-induced thrombocytopenia within past year
• Social factors affecting compliance or follow-up

Initial Anticoagulation

For Hemodynamically Stable Patients:

1. Direct Oral Anticoagulants (DOACs) - First-line therapy for most patients 2

   • Apixaban: 10 mg twice daily for 7 days, then 5 mg twice daily
   • Rivaroxaban: 15 mg twice daily for 21 days, then 20 mg daily

2. Low Molecular Weight Heparin (LMWH)

   • Enoxaparin: 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg once daily 3
   • Particularly useful for patients with active cancer, pregnancy, or when rapid reversal might be needed

3. Unfractionated Heparin (UFH)

   • Initial bolus of 80 U/kg followed by continuous infusion at 18 U/kg/hour
   • Target aPTT 1.5-2.3× control (46-70 seconds) 2
   • Preferred for patients with severe renal dysfunction (CrCl <30 mL/min) or when thrombolysis may be considered

For Hemodynamically Unstable Patients (High-Risk PE):

1. Systemic Thrombolysis

   • Alteplase 100 mg over 2 hours via peripheral vein 2
   • Consider for patients with cardiogenic shock and/or persistent arterial hypotension

2. Surgical Embolectomy or Catheter-Directed Intervention

   • Consider when thrombolysis is contraindicated or has failed 2

Special Considerations

Renal Impairment

• For severe renal dysfunction (CrCl <30 mL/min), use UFH rather than LMWH 2
• Avoid rivaroxaban if CrCl <15 mL/min 2

Cancer Patients

• LMWH is recommended for at least 6 months, followed by continued anticoagulation with either LMWH or vitamin K antagonists as long as cancer is active 2

Duration of Treatment

• For PE secondary to transient/reversible risk factors: 3 months
• For unprovoked PE or persistent risk factors: Extended (>3 months)
• For recurrent PE: Indefinite 2

Monitoring and Follow-up

• Regular clinical follow-up at 3-6 months to assess for:

  • Signs of chronic thromboembolic pulmonary hypertension (CTEPH)
  • Need for extended anticoagulation
  • Medication adherence and bleeding complications 2

• For patients on UFH, monitor aPTT regularly and adjust dosing according to protocol

• For patients on DOACs, routine laboratory monitoring is not required 2

Common Pitfalls to Avoid

1. Delaying anticoagulation while awaiting confirmatory imaging in patients with intermediate or high clinical probability of PE

   • Start anticoagulation before imaging if no contraindications exist 2

2. Failing to risk-stratify patients appropriately

   • This can lead to inappropriate treatment settings (inpatient vs. outpatient)

3. Overlooking right ventricular dysfunction in seemingly stable patients

   • Consider measuring cardiac biomarkers (BNP, NT-proBNP, hsTnI or hsTnT) in patients with RV dilatation on CT or echocardiography 1

4. Inappropriate use of thrombolysis in non-high-risk patients

   • Reserve systemic thrombolysis for hemodynamically unstable patients 2