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    Pulmonary Embolism Severity Index (PESI)

    Predicts 30-day outcome of patients with pulmonary embolism using 11 clinical criteria.
    When to Use
    Why Use

    In the setting of a patient diagnosed with PE, the PESI can be utilized to determine mortality and long term morbidity. For those determined to be very low risk (score ≤ 65), all studies showed a 30-day mortality <2%. In the validation, low risk (Class I and II) had a 90-day mortality of 1.1%. The non-inferiority trial demonstrated Class I and II could have been treated as outpatients assuming no other issues.

    The Pulmonary Embolism Severity Index (PESI) is a risk stratification tool that has been externally validated to determine the mortality and outcome of patients with newly diagnosed pulmonary embolism (PE).

    In the setting of a patient with renal failure or severe comorbidities, clinical judgement should be used over the PESI, as these patients were excluded in the validation study.

    • The PESI score determines risk of mortality and severity of complications.
    • The score does not require laboratory variables.
    • It is meant to aid in decision making, not replace it. Clinical judgement should always take precedence.
    • The PESI score determines clinical severity and can influence treatment setting for management of PE.
      • Class I and II patients may possibly be safely treated as outpatients in the right clinical setting.

    The PESI is designed to risk stratify patients who have been diagnosed with a PE in order to determine the severity of their disease. This can help physicians make decisions on the management of those patients who could potentially be treated as out-patient, as well as raise concern for those who are determined to be high-risk and could benefit from higher levels of care.



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    • Social situation should also be taken into account before considering outpatient management (including the appropriate administration of anticoagulants).
    • Given low mortality of low risk PE, outpatient management would save significant funds over hospitalization (cited as $4,500 per avoided admission).
    • The non-inferiority trial showed successful and safe outpatient management of Class I and II patients.


    • If the patient is considered very low (≤ 65) or low risk (66-85) by the PESI score.
      • Patient has an overall low risk of mortality or severe morbidity.
      • Consider outpatient management of PE if clinically appropriate and social factors allow for it.
    • If the patient is considered intermediate (86-105), high risk (106-125) or very high risk (>125) by the PESI.
      • Patient has an overall high risk of mortality and severe morbidity.
      • Consider higher levels of care (e.g., ICU) for those with higher scores.

    Critical Actions

    • The PESI is only meant for risk stratification of pulmonary embolism after the diagnosis has been made.
    • Findings which could point toward clinically significant PE should not be overlooked in the setting of a low PESI score.
    • Additional pathology which could lead to morbidity or mortality should not be overlooked in the setting of a low PESI score.
    • All results for the validation of the PESI were made with patients who were treated for PE initially with enoxaparin, and then encouraged to transition to vitamin K antagonists.


    Addition of the assigned points.

    Facts & Figures

    Score interpretation:

    PESI ScoreClassRisk 30 day Mortality

    Evidence Appraisal

    Derivation/Validation (Aujesky D, 2005)

    • The primary evaluation was designed to develop a prediction rule which classifies patients already diagnosed with pulmonary embolism on risk of mortality and morbidity.
    • Short-term mortality is cited to range from 2-95% based on severity of PE (submassive vs. cardiorespiratory arrest).
    • Patients were retrospectively identified from a healthcare database of inpatients >18 years old with a primary or secondary diagnosis of PE (plus a diagnosis of PE related complication, i.e., arrest, shock, pulmonary hypertension) from 2000-2002.
    • 15,531 patients from 186 hospitals were identified, with 10,354 (67%) randomly selected for derivation and 5,177 (33%) held for internal validation. The authors derived 11 criteria with regression analysis based on a main outcome of 30-day mortality.
    • Criteria: male sex, cancer, CHF, lung disease, pulse ≥110, SBP <100, RR ≥30, temp <36°C, ams, and O2 SAT < 90 mmHg.
    • Created 5 classes:
      1. Class I - Scores ≤ 65 indicate very low risk.
      2. Class II - Scores of 66-85 indicate low risk.
      3. Class III - Scores of 86-105 indicate intermediate risk.
      4. Class IV - Scores of 106-125 indicate high risk.
      5. Class V - Scores >125 indicate very high risk.
    • Externally validated in 221 ED patients in Switzerland and France, confirmed with CT scan and followed up for mortality and complications.
    • 30-day mortality rate for the derivation was 9.2% and for the internal validation was 9.5%. The external validation has a 30-day mortality rate of 2.7% but is complicated by a lower prevalence  of comorbidities.
      • Derivation mortality risk for level: I) 1.1%, II) 3.1%, III) 6.5%, IV) 10.4%, V) 24.5%.
      • Internal validation mortality risk for level: I) 1.6%, II) 3.5%, III) 7.1%, IV) 11.4%, V) 23.9%.
      • External validation mortality risk for level: I) 0%, II) 1.7%, III) 3.2%, IV) 4%, V) 10.0%.
    • Nonfatal cardiogenic shock or cardiorespiratory arrest occurred in less than 1.3% (derivation) of Class II, and less than 1.0% (internal validation) of Class I.

    Prospective Validation (Donzé J, 2008)

    • Prospectively enrolled patients during a clinical trial for a PE diagnostic algorithm.
    • Enrolled patients from 6 ED’s in Switzerland, France and Belgium between 2005 and 2006. ED patients with clinical suspicion of PE were included. Exclusion was contraindication to spiral CT or terminal illness, as well as prior diagnosis of PE.
    • Diagnosis included positive CT, angiography, V/Q scan or DVT with US.
    • 357 patients had confirmed PE. 186 (52%) were classified as Class I or II. 91 (25%) were Class III, 41 (11%) were Class IV and 39 (11%) were Class V.
    • No patients were lost to follow up. 8 (2%) received thrombolytics. 21 (5.9%) died - 9 (43%) of these with likely or definite PE.
    • No patients from risk Class I died. 2 (2%) from Class II died and both were from likely or definite PE. 7 (7.7%) from Class III, 5 (12.2%) from Class IV and 7 (17.9%) from Class V died.
    • When comparing low risk to high risk patients, PESI had a negative predictive value of 99% with a negative likelihood ratio of 0.2 for mortality.
    • Overall mortality for low risk (Class I and II) at 7 days was 0.5% and at 90 days was 1.1%. However, this study excluded high risk patients such as those with terminal illness or renal failure.

    Outpatient Management Trial (Aujesky D, 2011)

    • Open-label non-inferiority trial in 19 EDs in Switzerland, France, Belgium and USA.
    • Randomly assigned patients who had been diagnosed with symptomatic PE and low risk PESI scores (Class I or II) to inpatient or outpatient groups between 2007 and 2010. Excluded those in shock, hypoxia or bleeding risk.
    • Everyone got subcutaneous LMWH and then oral anticoagulation.
    • 334 patients enrolled. 171 were treated as outpatients, and 168 were treated as in-patients. 1 patient (0.6%) in each group died within 90 days. 1 (0.6%) outpatient and 0 inpatients had a recurrent PE. 3 (1.8%) outpatients and 0 inpatients had major bleeding events in 90 days.
    • Demonstrated non-inferiority of outpatient management for recurrent PE and death. Outpatient management was also effective for major bleeding up to 14 days, but an additional bleeding event (1 patient) 50 days after treatment did not allow the authors to show non-inferiority of out-patient management for bleeding to 90 days.


    Dr. Drahomir Aujesky

    About the Creator

    Drahomir Aujesky, MD, MS, is an active clinician-investigator who predominantly researches venous thromboembolism. He was previously a full-time clinician at the University of Lausanne in Switzerland and completed the intensive Clinical Research Training Program (CRTP) under the direction of Dr. Michael Fine at the University of Pittsburgh.

    To view Dr. Drahomir Aujesky's publications, visit PubMed

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