Background: Pulmonary embolism severity index, its simplified version, and shock index have been used for risk stratification in acute pulmonary embolism. In this study, we proposed a modification in severity index and evaluated the correlates and prognostic value of modification in severity index in this setting.

Methods: The study group comprised retrospectively evaluated 181 patients with acute pulmonary embolism. Systematic workup including pulmonary embolism severity index, its simplified version, shock index, biomarkers, and echocardiographic and multidetector computed tomography assessments was performed in all patients. Moreover, we calculated modification in severity index by multiplying original shock index (heart rate/systolic blood pressure ratio) and a third component, 1/pulse oxymetric saturation (pSat O2%) ratio. The primary endpoint was defined as all-cause mortality and hemodynamic collapse during the hospital stay.

Results: On the basis of initial risk stratification, ultrasound-assisted thrombolysis, systemic tissue-type plasminogen activator, and unfractionated heparin therapies were utilized in 83 (45.9%), 37 (20.4%), and 61 (33.7%) patients, respectively. The primary end-point occurred in 13 (7.2%) patients. Receiver-operating curve analysis revealed that modification in severity index had the highest area under the curve of 0.739 (0.588-0.890, P =.002) compared with shock index, pulmonary embolism severity index, or its simplified version. The modification in severity index > 0.989 predicted primary endpoint with 73% sensitivity and 54% specificity.

Conclusions: The modification in severity index seems to be a simple, quick, and compre-hensive risk assessment tool for bedside evaluation at initial stratification, in monitoring the clinical benefit from therapies, and decision-making for escalation to other reperfusion strategies in patients with acute pulmonary embolism. However, the prognostic value of modification in severity index needs to be validated with further studies.