Optimizing sPESI with heart rate threshold adjustments for risk stratification in acute pulmonary embolism: A retrospective cohort study

INTRODUCTION: The simplified Pulmonary Embolism Severity Index (sPESI) is a validated tool for risk stratification in acute pulmonary embolism (PE). It incorporates heart rate (HR) ⩾ 110 beats per minute (bpm) as a prognostic factor; however, recent evidence suggests that lower HR thresholds may also be clinically relevant. This study evaluated the prognostic performance of sPESI-based models using varying HR cut-offs and assessed the incremental value of adding right ventricular dysfunction (RVD). METHODS: We conducted a retrospective cohort study of 696 outpatients with objectively confirmed PE between 2014 and 2019 in a Canadian health region. sPESI models were recalculated using HR thresholds of ⩾ 80, ⩾ 90, ⩾ 100, and ⩾ 110 bpm. The addition of imaging-confirmed RVD was also examined. Outcomes included 30- and 90-day all-cause mortality. Model performance was assessed using logistic regression, area under the curve (AUC), Youden's Index and net reclassification index (NRI). RESULTS: Lowering the HR threshold improved event detection and reclassification. HR ⩾ 100 bpm provided the most balanced performance for 30-day mortality (AUC 74.7%, Youden Index 0.414), and HR ⩾ 90 bpm offered greater sensitivity. Adding RVD modestly improved model discrimination, with sPESI + RVD at HR ⩾ 80 bpm achieving the highest sensitivity (92.9%) and negative predictive value (> 99%) for 30-day mortality. The strongest association with mortality was observed for sPESI alone HR ⩾ 100 bpm (OR 2.06; 95% CI: 1.47-2.92). Findings remained consistent in a hospitalized-only sensitivity analysis. CONCLUSION: Modifying HR thresholds within the sPESI model, particularly at ⩾ 100 bpm, and incorporating RVD meaningfully improves short-term mortality prediction in acute PE. These refinements may enhance clinical decision-making, especially in selecting patients for safe outpatient management.