Pulmonary Embolism Severity Index (PESI)
Why Use
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.
When to 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.
Formula
Pearls / Pitfalls
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.
Management
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.
Advice
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.
More Information
Interpretation: PESI Score Class Risk 30 day mortality 0-65 I 0.0-1.6% 66-85 II 1.7-3.5% 86-105 III 3.2-7.1% 106-125 IV 4.0-11.4% ≥125 V 10-24.5%