18th February 2025

Management of PE

PE management is usually guided by scoring systems like the PESI (pulmonary embolism severity index) or sPESI (simplified PESI). These have categories of high, intermediate-high, intermediate-low and low risk PEs. High risk PEs (haemodynamically unstable patients) are usually thrombolysed and non-high risk PEs (haemodynamically stable) are usually treated with anticoagulation but with different durations of hospitalisation for monitoring.

Haemodynamically unstable patients

High risk, or “massive” PE is defined as acute PE with haemodynamic instability. There are three main categories for haemodynamic instability. Any single one of the following will count for the definition:

• Cardiac arrest
• Systolic BP <90 mmHg with end-organ hypoperfusion (confusion, skin clamminess, diaphoresis, mottling, oliguria, anuria, raised lactate)
• Systolic BP <90 mmHg for more than 15 minutes, with no additional contributory cause, such as sepsis, hypovolaemia or arrhythmia

For those without contraindications, urgent systemic thrombolysis is given, usually with IV alteplase (bolus then infusion). After thrombolysis, APTTR (APTT ratio) is monitored, and unfractionated heparin started when APTTR is <2.0 (normal: 0.8-1.2). This is continued until the patient is haemodynamically stable, at which point they can be switched to LMWH. If a patient is particularly frail or has relative contraindications to thrombolysis then senior input is needed, with IV UFH infusion being started until a decision about thrombolysis is made.

If there is continued deterioration despite thrombolysis, or if thrombolysis is contraindicated, surgical embolectomy or percutaneous catheter-directed therapy are options.

Haemodynamically stable patients

Anticoagulation is required for haemodynamically stable patients with PE:

• First line: rivaroxaban or apixaban
• Second line: LMWH for at least 5 days followed by dabigatran or edoxaban or warfarin with at least 5 days of LMWH bridging therapy

Mechanical interventions, e.g. IVC (inferior vena cava) filter, can be considered in patients who cannot have anticoagulation or who develop recurrent PE despite adequate anticoagulation. Thrombolytic therapy (systemic or catheter-directed) and open pulmonary embolectomy are alternatives.

Ongoing management of PE

The duration of anticoagulation therapy depends on whether or not the PE was provoked by a transient risk factor:

• Provoked: standard duration of anticoagulation is 3 months
• Unprovoked: longer-term, from 6 months to indefinite anticoagulation may be needed

A full history and examination should be performed, as well as standard blood tests. If no relevant signs or symptoms are found, no further investigations for malignancy screening are required.

If there is a plan to stop anticoagulation treatment in unprovoked PE, it is advised to consider testing for antiphospholipid antibodies and to test for hereditary thrombophilia in those with first-degree relatives who have had DVT or PE. There is no need to test for hereditary thrombophilia in those who are continuing anticoagulation.