Table 2 Methods and tools for risk stratification of pulmonary embolism (PE)
Parameter(s)AdvantagesLimitations
Transthoracic echocardiography

  • RV hypokinesis

  • Non-invasive

  • Caution: not a diagnostic test! A normal echocardiogram does not exclude PE in normotensive patients

  • RV dilatation

  • Method established for over 20 years

  • Not all studies could confirm prognostic implications

  • Leftward septal shift

  • Can be performed at the bedside, no need for patient transportation

  • Echocardiographic parameters still not standardised, differed between studies

  • Pulmonary hypertension (estimated)

  • Particularly useful for confirmation of PE or differential diagnosis in unstable, high risk patients

  • Sensitivity probably lower than that of biomarkers

  • Exact specificity unclear; up to 50% of patients had “RV dysfunction” in some studies

  • Limited availability on a round-the-clock basis in some hospitals

Multidetector CT scan (MDCT)

  • Increased RV/LV diameter (or area) ratio

  • Non-invasive, fast method

  • Only retrospective data available to date

  • Pulmonary artery obstruction index (clot burden)

  • MDCT increasingly available in hospitals

  • Not all studies could show prognostic implications, particularly for PA clot burden

  • Diagnosis and risk assessment of PE with one single method

  • Studies included patients with hypotension and/or shock; independent prognostic value of CT unclear

  • Cutoff value for defining “abnormal” RV/LV ratio not standardised

  • Specificity of RV/LV ratio probably low; >50% of patients had “abnormal” ratio in some studies

  • Exposure to radiation, contrast medium

Biomarkers

  • Cardiac troponins I and T

  • Troponin and BNP/NT-proBNP assays widely available

  • Low specificity and positive prognostic value; unsuitable for ruling in high risk PE

  • Natriuretic peptides (BNP, NT-proBNP)

  • High prognostic sensitivity and negative predictive value; suitable for ruling out high risk PE

  • Troponin values may not rise until several hours after symptom onset; repeated measurements necessary

  • New biomarkers (H-FABP, GDF-15)

  • New biomarkers appear to possess favourable kinetics (H-FABP), higher specificity and incremental value (GDF-15)

  • Optimal cutoff values of BNP not prospectively tested

  • Further validation of new biomarkers necessary, focus on normotensive patients

  • BNP, brain natriuretic peptide; GDF-15, growth differentiation factor 15; H-FABP, heart-type fatty acid-binding protein; LV, left ventricle; NT-proBNP, N-terminal proBNP; PA, pulmonary artery; RV, right ventricle.