Modification of Simplified Pulmonary Embolism Severity Index and its Prognostic Value in Patients with Acute Pulmonary Embolism

Background Various risk stratification systems have been used to predict the clinical outcome of patients with pulmonary embolism (PE). In this study we present a modification of the simplified Pulmonary Embolism Severity Index (S-PESI) score and evaluate its accuracy in predicting the outcome of these patients. Materials and Methods Patients older than 18 years with documented PE were enrolled in this study. S-PESI was calculated in all patients. We added electrocardiographic evidence of right ventricular strain as a new criteria and replaced the O2 saturation of <90% in S-PESI score with PaO2 /PaCO2 ratio obtained from the arterial blood gas analysis as two newly modified criteria to define a modified form of S-PESI system (modified s-PESI). Patients were followed for about one year in outpatient clinics. Any deaths attributable to PE or for unknown reasons were considered as PE related. We defined Major Adverse Cardio-Pulmonary Events (MACPE) as sum of one-year mortality, need for thrombolysis and mechanical ventilation during index hospitalisation. Results Among 300 enrolled patients, in-hospital mortality occurred in 38 (12.7%) and one-year mortality in 73 (24.3%) patients. Considering a cut-off point of 3, modified s-PESI score had a lower sensitivity (49.3% vs. 89%) and higher specificity (79.4% vs. 37.7%) than S-PESI to predict one-year mortality. Area Under Curve (AUC) to predict MACPE was significantly higher for modified s-PESI (0.692 vs 0.730, P=0.012). Conclusion The modified s-PESI is superior to S-PESI in predicting one-year outcome in patients with PE and can be used for more accurate risk stratification of these patients.