Pulmonology

PESI (Pulmonary Embolism Severity Index) Calculator

Q: When should PESI be used instead of sPESI?

sPESI is faster and simpler, with comparable accuracy for distinguishing low from high risk. PESI provides finer separation into 5 classes and is preferred in research. In routine clinical practice, sPESI is usually sufficient.

Q: Can a patient with PESI class I be sent home?

In class I, without complicating factors (decompensated heart failure, pregnancy, severe CKD) and under favorable social circumstances, yes — on a DOAC with mandatory follow-up at 48-72 hours.

Q: What should be done for PESI class III-IV?

Hospitalization with anticoagulant therapy. Additionally assess echocardiography (right ventricular dysfunction) and troponin — if these are elevated, the effective risk becomes 'intermediate-high,' and the patient should be observed on a monitored ward.

Q: Is PESI used to decide on thrombolysis?

Indirectly. Thrombolysis is indicated for high-risk PE (hemodynamic instability). In class IV-V with right ventricular dysfunction and elevated troponin, thrombolysis or systemic alternatives are discussed.

Risk stratification in confirmed PE (30-day mortality)

Primary source: Aujesky D et al. Am J Respir Crit Care Med 2005; 172(8): 1041-1046

Aleksandr A. Aulov, MD, internal medicine Last clinical review: April 28, 2026

Online calculation

Age

The score equals the number of completed years

years

Male sex

Active malignancy

History of heart failure

Chronic lung disease

Heart rate ≥ 110/min

SBP < 100 mm Hg

Respiratory rate ≥ 30/min

Body temperature < 36°C

Altered mental status / disorientation

O₂ saturation < 90%

Elevated blood urea nitrogen (BUN > 43 mg/dL or urea > 14 mmol/L)

About this score

PESI (Pulmonary Embolism Severity Index) is a prognostic score for estimating 30-day mortality in patients with confirmed pulmonary embolism (PE). It was developed by D. Aujesky et al. (Am J Respir Crit Care Med, 2005) in a cohort of 15,531 patients. It includes 11 clinical parameters: age, sex, active cancer, history of heart failure, chronic lung disease, heart rate, SBP, respiratory rate, temperature, altered mental status, and SaO₂.

The total score divides patients into 5 risk classes: I (≤ 65 points, mortality 0-1.6%), II (66-85, 1.7-3.5%), III (86-105, 3.2-7.1%), IV (106-125, 4.0-11.4%), V (>125, 10-24.5%). Classes I-II are considered low risk — these patients may be candidates for outpatient treatment with direct oral anticoagulants, supported by data from the OTPE trial and endorsed by the 2019 ESC guidelines.

PESI is used after PE has been confirmed (CT pulmonary angiography or scintigraphy), not for pretest probability assessment. For the decision between hospitalization and outpatient management, the simplified sPESI (only 6 items) is often used instead, as it is clinically comparable in accuracy and faster to calculate.

When to use

Confirmed PE — to guide the intensity and setting of care (outpatient vs inpatient vs ICU).
Risk stratification before discharge from the emergency department — class I-II may allow early management on DOACs at home under favorable social circumstances.
Predicting 30-day mortality to plan follow-up and inform discussions with family.
Documenting severity in the medical record and guiding choice of anticoagulant therapy.

Clinical example

Case

78-year-old woman with confirmed PE (CT-PA showing bilateral segmental filling defects). History of breast cancer, NYHA class II heart failure. Heart rate 112/min, SBP 102 mm Hg, respiratory rate 26/min, temperature 36.7°C, alert and oriented, SaO₂ 89% on room air.

Calculation

Age 78 (+78) + female sex (+10) + cancer (+30) + heart failure (+10) + heart rate > 110 (+20) + respiratory rate > 30 — no, 26 (0) + temperature < 36 — no (0) + SaO₂ < 90 (+20) = 168 points.

Interpretation and management

Class V (very high risk, 30-day mortality 10-24.5%). Hospitalization is indicated, preferably in the ICU. Further work-up should include echocardiography, troponin, and BNP. Therapy consists of full-dose anticoagulation; if hemodynamic instability develops, consider thrombolysis or thrombectomy.

Limitations and cautions

Applicable only after PE has been confirmed — not intended for pretest probability assessment (use Wells or Geneva for that).
Does not account for right ventricular dysfunction on echocardiography or biomarkers (troponin, BNP) — for full risk stratification, the ESC recommends combining PESI with echocardiography in class III-IV.
In cancer patients, malignancy alone contributes a large number of points (+30), which may overestimate the class — clinical assessment of stability remains primary.
Not validated in pregnancy.

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Frequently asked questions

When should PESI be used instead of sPESI?

sPESI is faster and simpler, with comparable accuracy for distinguishing low from high risk. PESI provides finer separation into 5 classes and is preferred in research. In routine clinical practice, sPESI is usually sufficient.

Can a patient with PESI class I be sent home?

In class I, without complicating factors (decompensated heart failure, pregnancy, severe CKD) and under favorable social circumstances, yes — on a DOAC with mandatory follow-up at 48-72 hours.

What should be done for PESI class III-IV?

Hospitalization with anticoagulant therapy. Additionally assess echocardiography (right ventricular dysfunction) and troponin — if these are elevated, the effective risk becomes 'intermediate-high,' and the patient should be observed on a monitored ward.

Is PESI used to decide on thrombolysis?

Indirectly. Thrombolysis is indicated for high-risk PE (hemodynamic instability). In class IV-V with right ventricular dysfunction and elevated troponin, thrombolysis or systemic alternatives are discussed.

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Aleksandr A. Aulov Physician, internal medicine, Sechenov School — independent medical education platform. Calculators are compiled from the original publications and current clinical guidelines. Interpretation thresholds follow the source study unless stated otherwise.

This calculator is intended for healthcare professionals. Do not use it for self-diagnosis or self-treatment. Management decisions are made by the treating clinician based on the full clinical picture of the individual patient.