Severity of pulmonary embolism (PE)

The task force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology suggest that the severity of PE should be understood according to the PE-related early mortality risk rather than the anatomical burden and the shape and distribution of intrapulmonary emboli (1).

Hence the task force suggests that the currently used terms such as 'massive', 'sub-massive' and 'non-massive' be replaced with the estimated level of the risk of PE-related early death (during the acute phase in the hospital or within 30 days ) (1).

Initially the patients can be divided according to the haemodynamic stability to:

• high-risk PE
  • the patient is unstable haemodynamically and may present with
    • shock or
    • persistent hypotension - systolic blood pressure <90 mmHg or a drop of >40 mmHg for more than 15 minutes that was not triggered by new onset arrhythmia, hypovolemia or sepsis
  • is a life threatening condition
    • requires specific diagnostic and therapeutic strategies
    • short term mortality is >15%
      
      
• non-high-risk PE
  • the patient is haemodynamically stable
  • can be further divided according to presence of markers of RV dysfunction and/or myocardial injury into
    • intermediate risk PE - at least one RV dysfunction or one myocardial injury marker is positive
    • low risk PE - all checked RV dysfunction and myocardial injury markers are found negative, short term PE related mortality is <1% (1)

Note:

• principal markers used in risk stratification of non-high-risk PE are:
  • right ventricular dysfunction
    • RV dilatation, hypokinesis or pressure overload on echocardiography
    • RV dilatation on spiral computed tomography
    • BNP or NT-pro BNP elevation
    • Elevated right heart pressure at RHC
  • myocardial injury
    • cardiac troponin T or I positive
    • human fatty acid binding protein (H-FABP) elevation

Note

The assessment of clinical probability is a key step in the diagnostic approach to PE. Assess the clinical probability of PE in haemodynamically stable patients using a combination of the Pulmonary Embolism Rule-Out Criteria (the PERC rule), the Wells (or Geneva) score, plus D-dimer testing if indicated (2, 3)

References:

1. Torbicki A et al. Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Eur Heart J. 2008;29(18):2276-315.
2. Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J. 2020 Jan 21;41(4):543-603.
3. National Institute for Health and Care Excellence. Venous thromboembolic diseases: diagnosis, management and thrombophilia testing. Aug 2023 [internet publication].