Pulmonary Embolism Severity Index (PESI)
Risk stratify patients with PE to guide disposition. Low-risk PE may avoid admission in resource-limited settings.
The Pulmonary Embolism Severity Index (PESI) stratifies 30-day mortality risk in patients with confirmed acute pulmonary embolism using readily available clinical variables. It helps identify low-risk patients who may be candidates for outpatient management or early discharge, and higher-risk patients needing closer monitoring. PESI is endorsed in major guidelines as a validated prognostic tool for disposition decisions.
🧮 Interactive Calculator
📐 Formula
Points: Age + Male(10) + Cancer(30) + CHF(10) + Chronic lung(10) + HR≥110(20) + SBP<100(30) + RR≥30(20) + Temp<36(20) + SpO2<90%(20). Class I-II: low risk
Reference: Aujesky et al., 2005
When to Use
- Risk stratification of a patient with newly confirmed acute pulmonary embolism
- Selecting low-risk PE candidates for outpatient treatment or early discharge, especially in resource-limited settings
- Supporting decisions on level of care (ward vs monitored/high-dependency bed)
- Complementing imaging (RV strain on CT/echo) and biomarkers in prognostic assessment
- As part of protocolised PE pathways in the emergency department
How It Works
- PESI sums points across 11 weighted variables to produce a total score that maps to five risk classes.
- Age contributes its value in years; being male adds 10 points.
- Comorbidities: history of cancer +30, heart failure +10, chronic lung disease +10.
- Vital-sign derangements: pulse >=110/min +20, systolic BP <100 mmHg +30, respiratory rate >=30/min +20, temperature <36 C +20, oxygen saturation <90% +20, and altered mental status +60.
- The points are added to give a raw score; a Simplified PESI (sPESI) alternative uses six equally weighted binary variables where any positive point denotes higher risk.
- The tool assumes PE is already confirmed; it is a prognostic, not a diagnostic, instrument.
Interpreting the Result
- Class I (<=65 points): very low 30-day mortality, approximately 0-1.6%.
- Class II (66-85): low risk, approximately 1.7-3.5% mortality.
- Class III (86-105): intermediate risk, approximately 3.2-7.1% mortality.
- Class IV (106-125): high risk, approximately 4.0-11.4% mortality.
- Class V (>125): very high risk, approximately 10-24.5% mortality.
- Classes I-II are considered low risk and may be suitable for outpatient management if no other contraindication (e.g. haemodynamic instability, RV dysfunction, bleeding risk, poor social support).
- For sPESI, a score of 0 defines low risk (~1% mortality) and >=1 higher risk (~10.9%).
Limitations & Pitfalls
- Prognostic only; it neither diagnoses PE nor guides thrombolysis in isolation.
- Low-risk classification does not override haemodynamic instability, right-ventricular dysfunction, or elevated troponin, which mandate higher acuity care.
- Does not incorporate imaging findings, biomarkers, or comorbidities such as renal failure that affect outcome.
- Age heavily influences the score, so young patients with severe PE may be under-classified.
- Suitability for outpatient care also depends on social factors, adherence, and follow-up access not captured by the score.
- Derived largely in general PE populations; performance may differ in cancer-associated or incidentally diagnosed PE.
References
- Aujesky D et al. Derivation and validation of a prognostic model for pulmonary embolism (PESI). Am J Respir Crit Care Med. 2005.
- Jimenez D et al. Simplification of the Pulmonary Embolism Severity Index (sPESI). Arch Intern Med. 2010.
- Konstantinides SV et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2020.
- Aujesky D et al. Outpatient versus inpatient treatment for low-risk pulmonary embolism (randomised trial). Lancet. 2011.
⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.