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

Initial Management of Pulmonary Embolism (PE)

For initial management of pulmonary embolism, low-molecular-weight heparin (LMWH) is recommended over unfractionated heparin (UFH) for most patients, while intravenous UFH is preferred for hemodynamically unstable patients with massive PE, and thrombolysis is the first-line treatment for massive PE with hemodynamic instability. 1

Risk Stratification

First, determine the severity of PE:

1. High-risk (massive) PE:

   • Characterized by hemodynamic instability, hypotension, shock, or cardiac arrest
   • Signs include collapse, hypoxia, engorged neck veins, and right ventricular gallop 1

2. Intermediate to low-risk (submassive or non-massive) PE:

   • Hemodynamically stable patients

Diagnostic Approach

• For unstable patients: Echocardiography is the most useful initial test 1
• For stable patients: CT pulmonary angiography (CTPA) is the recommended initial imaging modality 2
• If CTPA unavailable: Isotope lung scanning may be considered if chest radiograph is normal and there's no significant concurrent cardiopulmonary disease 2
• For patients with coexisting DVT: Leg ultrasound as the initial imaging test may be sufficient 2

Treatment Algorithm

For High-Risk (Massive) PE:

1. Immediate thrombolysis is the first-line treatment 2, 1

   • A 50 mg bolus of alteplase is recommended 2, 1
   • Thrombolysis may be instituted on clinical grounds alone if cardiac arrest is imminent 2
   • Contraindications to thrombolysis should be ignored in life-threatening PE 1

2. If thrombolysis is contraindicated or fails:

   • Consider surgical embolectomy
   • Catheter embolectomy or thrombus fragmentation may be considered when surgical options aren't immediately available 1

For Non-Massive PE:

1. Anticoagulation:

   • LMWH is preferable to UFH for most patients due to equal efficacy, safety, and easier use 2, 1
   • UFH should be considered in situations where rapid reversal may be needed 2
   • Direct oral anticoagulants (DOACs) are first-line for low to intermediate-risk PE 1

2. DOAC options:

   • Apixaban: 10 mg twice daily for 7 days, followed by 5 mg twice daily
   • Rivaroxaban: 15 mg twice daily for 21 days, followed by 20 mg once daily
   • Dabigatran: 150 mg twice daily after initial LMWH
   • Edoxaban: 60 mg once daily (30 mg once daily if CrCl 30-50 mL/min or body weight <60 kg) 1

3. If DOACs are contraindicated: LMWH or fondaparinux is preferred over UFH 1

Duration of Treatment

• Secondary PE due to transient/reversible risk factors: 3 months
• Unprovoked PE or persistent risk factors: Extended (>3 months)
• Recurrent PE: Indefinite 1

Outpatient Management Considerations

Outpatient treatment is possible if the patient:

• Is hemodynamically stable
• Has no need for thrombolysis
• Has oxygen saturation >90% on room air
• Has no severe pain requiring IV analgesia
• Has no high bleeding risk
• Has no severe renal/liver disease
• Has adequate social support and follow-up 1

Common Pitfalls and Caveats

1. Delay in treatment: Heparin should be given to patients with intermediate or high clinical probability before imaging 2

2. Inappropriate use of D-dimer:

   • Should only be considered following assessment of clinical probability
   • Should not be performed in those with high clinical probability of PE
   • A negative D-dimer test reliably excludes PE in patients with low or intermediate clinical probability 2

3. Failure to consider alternative diagnoses: An alternative clinical explanation should always be considered at presentation and sought when PE is excluded 2

4. Inappropriate thrombolysis: Should not be used as first-line treatment in non-massive PE 2

5. Premature discontinuation of anticoagulation: Oral anticoagulation should only be commenced once VTE has been reliably confirmed, with heparin discontinued only when target INR of 2.0-3.0 is achieved 2