An exploratory model for short-term risk stratification in intermediate-high-risk pulmonary embolism running head:...

Intermediate-high-risk pulmonary embolism (PE) patients are at increased risk of sudden clinical deterioration within the first hours after symptom onset.

We aimed to develop and validate a practical prediction model and scoring system for identifying intermediate-high-risk PE patients at elevated risk of 48-hour clinical deterioration after symptom onset.

The STAMP score was developed using data from 450 intermediate-high-risk PE patients enrolled in the Italian Pulmonary Embolism Registry (ClinicalTrials.gov: NCT01604538), incorporating demographic, clinical, and imaging variables identified through multivariable analyses.

A derivation cohort of 270 patients was used to create the score, which was subsequently validated in 180 patients. In the derivation cohort, multivariate analysis identified five independent predictors of 48-hour clinical deterioration: age ≥65 years (1 point), chest pain (1 point), syncope (2 points), TAPSE/PASP ≤0.33 (2 points), and mean arterial pressure (MAP) ≤81.5 mmHg (2 points). Based on the total score, patients were stratified into low (0-2 points), intermediate (3-5 points), and high (6-8 points) probability groups, with event rates significantly increasing across categories (p<0.001) in both derivation and validation cohorts. The STAMP score demonstrated good diagnostic performance, with areas under the curve of 0.86 and 0.85, C-statistics of 0.81 and 0.80, and Hosmer-Lemeshow p-values of 0.47 and 0.45, respectively.

The STAMP score is a novel, simple, and accurate tool that enhances early risk stratification in intermediate-high-risk PE patients, improving the identification of those at greatest risk of 48-hour clinical deterioration.