The validation and reproducibility of the pulmonary embolism severity index

Background: Rapid, accurate risk stratification is paramount in managing patients with acute pulmonary embolism (PE). The PE Severity Index (PESI) is a simple tool that risk stratifies patients with acute PE. Objectives: We sought to validate the PESI as a predictor of short- and intermediate-term mortality and to determine the inter-rater variability. Patients/Methods: We retrospectively identified all patients with acute PE between October 2007 and February 2009. Two clinicians reviewed charts and independently scored PESI blinded to each other and to patient outcomes. Thirty- and 90-day mortality served as study endpoints and vital status was assessed via the Social Security Death Index. To facilitate analyses, raw PESI score was converted into risk class groups (I-V) and further dichotomized into low risk (I-II) vs. high risk (III-V) groups. Intraclass correlation and the kappa statistic were used to determine inter-rater variability. Results: The cohort included 302 subjects (mean age, 59.7 +/- 17.2 years; 44% male). All-cause 30- and 90-day mortalities were 3.0% and 4.0%, respectively. The mortality rate increased as raw PESI score increased. Risk of death correlated with risk class (P < 0.001). There were no deaths in risk classes I-III, but 30- and 90-day mortality for class V were 9.2% and 10.5%, respectively. Overall, mean PESI scores were similar between observers: 103.3 +/- 39.3 and 96.5 +/- 37.6 (P = NS). The inter-rater variability was good (kappa = 0.69; P < 0.0001). Conclusions: The PESI correlates with 30- and 90-day mortality. It represents a reproducible scoring tool to risk stratify patients with acute PE.