Emergency Medicine
PESI (PE Severity Index)
30-day mortality risk in pulmonary embolism.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The Pulmonary Embolism Severity Index (PESI) predicts 30-day mortality in patients with confirmed pulmonary embolism (PE) and helps identify those at low enough risk to be considered for outpatient treatment. It combines eleven weighted variables: age (one point per year), male sex, cancer, heart failure, chronic lung disease, and the acute findings of tachycardia, hypotension, tachypnoea, hypothermia, altered mental status and hypoxaemia. The points sum to a total that is grouped into five risk classes. A simplified version (sPESI) collapses these into fewer dichotomous variables.
Interpreting the result
Classes I (≤65) and II (66–85) are low risk, class III (86–105) intermediate, and classes IV (106–125) and V (>125) high risk, with 30-day mortality rising sharply across the classes. Low-risk patients (classes I–II, or sPESI of zero) have a low expected mortality and may be suitable for early discharge or outpatient management with appropriate support. Higher classes indicate the need for inpatient monitoring and, in some cases, escalation. The score informs disposition but must be combined with right-ventricular assessment and clinical judgement.
Advice
Classes I–II (≤85 points) are low risk and may be suitable for outpatient treatment with appropriate support. Use with clinical judgement and local pathways.
Worked example
A 72-year-old man with chronic lung disease and a heart rate of 115/min, but normal blood pressure, oxygenation and mental status, scores 72 (age) + 10 (male) + 10 (lung disease) + 20 (tachycardia) = 112 points — class IV, high risk — favouring inpatient management rather than early discharge.
Pearls / pitfalls
- Even low-risk PESI patients need haemodynamic stability and adequate home/social support before outpatient management is considered.
- PESI does not include imaging or biomarkers — combine it with right-ventricular function (echo or CT) and troponin to refine intermediate-risk patients.
- Age dominates the score, so very elderly patients with otherwise benign features can still fall into a higher class.
- A high-risk PE with shock or hypotension is a medical emergency and overrides any reassurance the score might suggest.
Evidence & validation
Derived and validated by Aujesky et al. (2005) and reproduced widely, including for the simplified sPESI; it is referenced in ESC guidance on PE for risk stratification and selection of patients for home treatment.
Frequently asked questions
What does the PESI score predict?
It estimates the risk of death within 30 days of a confirmed pulmonary embolism. It is mainly used to identify low-risk patients who might be suitable for outpatient treatment.
Which patients are low risk?
Classes I and II (a total of 85 points or fewer), or a simplified PESI of zero, indicate low risk. Such patients may be considered for early discharge if they are haemodynamically stable and have adequate support.
How does PESI differ from sPESI?
The simplified PESI (sPESI) uses fewer, dichotomous variables and classifies patients simply as low risk (score 0) or higher risk. It is easier to calculate while retaining good ability to identify low-risk patients.
Does a low score mean home treatment is safe?
A low score supports it but is not sufficient on its own — haemodynamic stability, right-ventricular function, bleeding risk and social circumstances must also be assessed. Local pathways and clinical judgement guide the final decision.
Why does age carry so much weight?
Age contributes one point per year, so it strongly influences the total and can push otherwise well patients into a higher class. This reflects the strong effect of age on PE mortality but means the score should be read alongside the clinical picture.
References
- Aujesky D, Obrosky DS, Stone RA, et al. Derivation and validation of a prognostic model for pulmonary embolism. Am J Respir Crit Care Med. 2005;172(8):1041–1046.
- Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2020;41(4):543–603.
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