Pulmonary Embolism Severity Index (PESI) Score

Stratifies pulmonary embolism (PE) mortality risk based on clinical data.

In the text below the calculator there is more information about the score and its result interpretation and about the original study.

The pulmonary embolism severity index (PESI) score predicts 30-day mortality risk in patients diagnosed with PE based on clinical data such as systolic blood pressure or oxygen saturation and on presence or absence of altered mental status or malignancy.

The following table introduces the prognosis classification from the pulmonary embolism severity index and the 30-day mortality risk and associated probability:

PESI Score Class Mortality Risk Probability
0 - 65 I Very low up to 1.6%
66 - 85 II Low 1.7 - 3.5%
86 - 105 III Moderate 3.2 - 7.1%
106 - 125 IV High 4 - 11.4%
> 126 V Very high 10 - 24.5%


Age (1 point per year)


Patient gender


Temperature <36°C / 96.8°F


Systolic blood pressure <100 mmHg


Heart rate >110 bpm


Respiratory rate >30 bpm


Oxygen saturation less than 90%


History of chronic pulmonary disease


History of heart failure


Altered mental status



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PESI explained

The pulmonary embolism severity index (PESI score) stratifies mortality risk in PE (can also be used for morbidity prediction) in 5 severity classes and offers a probability of adverse outcome.

This risk stratification assessment is based on 11 clinical variables that refer to patient status and were found by the original study to be independent predictors of PE mortality.

These are weighted differently depending on the contribution of the variable in the prediction rule.

The following table introduces the 11 variables and the number of points awarded to them.

PESI variable Points awarded Description
1. Age of the patient 1 per year The higher the age, the greater the mortality risk.
2. Gender Male (20)
Female (0)
Men pose a higher risk of PE mortality and morbidity.
3. Temperature <36°C / 96.8°F 20 Low body temperature is associated with impaired body heat regulation.
4. Systolic blood pressure <100 mmHg 30 Decreased blood pressure as risk factor.
5. Heart rate >110 bpm 20 Pulse higher than 110 beats per minute even at rest.
6. Respiratory rate >30 breaths per minute 20 Increased respiratory rate even at rest.
7. Arterial oxygen saturation below 90% 20 With or without supplemented oxygen.
8. History of chronic lung disease 10 Previous diagnosed pulmonary condition.
9. History of heart failure 10 Previous diagnosed heart condition.
10. Alteration of mental status 60 Refers to loss of consciousness.
11. Malignancy 30 History of malignancy, in treatment or palliative.

Result interpretation

The prognosis classification in five severity classes and their associated 30-day mortality risk and probability, can be found in the table below:

PESI Score Class Mortality Risk Probability
0 - 65 I Very low up to 1.6%
66 - 85 II Low 1.7 - 3.5%
86 - 105 III Moderate 3.2 - 7.1%
106 - 125 IV High 4 - 11.4%
>126 V Very high 10 - 24.5%

Low risk classes, I and II may be considered for outpatient treatment. High risk cases however, classes III, IV and V require higher levels of care, usually in the ICU.


About the study

The PESI was created in 2005 by Aujesky et al. following a study on 15,531 patients diagnosed with PE and treated in 186 Pennsylvania hospitals. 67% of the sample was used in derivation of the index and 33% in validation. The PESI was also externally validated in 221 patients.

The prediction model was derived using logistic regression with 30-day mortality as the primary outcome and with several patient data as potential predictor variables.

11 variables were independently associated with mortality from PE and helped classify patients in five severity classes (described above in result interpretation).

The index was found to be reliable in classifying patients in terms of 30-day mortality risk and can contribute to initial treatment guidance.


Prognosis in PE

PE is a potentially fatal disorder but mortality rates for untreated PE have decreased in time. Prognosis in pulmonary embolism is highly dependent on:

■ The pulmonary area affected;

■ The size and placement of the clot;

■ The existence of other medical conditions;

■ The existence of associated risk factors.

In terms of clot blockage, the bigger the clot and the more important the blood vessel blocked is, the greater the risk of adverse outcome. If the blood clot breaks and enters the lung, death is rapid because the lung cannot provide oxygen to the blood anymore and pressure collapses.

In less severe cases, in hospital treatment with blood thinners is required. Medication is also prescribed for at least 6 months after the episode. For some patients, urgent surgery to apply a clot preventing filter, may be necessary.


Original source

Aujesky D, Obrosky DS, Stone RA, Auble TE, Perrier A, Cornuz J, Roy PM, Fine MJ. Derivation and validation of a prognostic model for pulmonary embolism. Am J Respir Crit Care Med. 2005; 172(8):1041-6.


Donzé J, Le Gal G, Fine MJ, Roy PM, Sanchez O, Verschuren F, Cornuz J, Meyer G, Perrier A, Righini M, Aujesky D. Prospective validation of the Pulmonary Embolism Severity Index. A clinical prognostic model for pulmonary embolism. Thromb Haemost. 2008; 100(5):943-8.

Other references

1. Aujesky D, Roy PM, Verschuren F, Righini M, Osterwalder J, Egloff M, Renaud B, Verhamme P, Stone RA, Legall C, Sanchez O, Pugh NA, N'gako A, Cornuz J, Hugli O, Beer HJ, Perrier A, Fine MJ, Yealy DM. Outpatient versus inpatient treatment for patients with acute pulmonary embolism: an international, open-label, randomised, non-inferiority trial. Lancet. 2011; 378(9785):41-8.

2. Wicki JPerrier APerneger TVBounameaux HJunod AF. Predicting adverse outcome in patients with acute pulmonary embolism: a risk score. Thromb Haemost 2000; 84 (4) 548 - 552.

Specialty: Pulmonology

System: Respiratory

Objective: Mortality Prediction

Type: Score

No. Of Items: 11

Year Of Study: 2005

Abbreviation: PESI

Article By: Denise Nedea

Published On: June 10, 2017

Last Checked: June 10, 2017

Next Review: June 10, 2023