Abstract / Summary
Abstract Background The Simplified Geneva Score (SGS) incorporates two heart-rate thresholds. Multiple heart-rate measurements are commonly recorded during emergency department (ED) assessment. While the original SGS specifies use of mean heart rate, real-world implementation is unlikely to reflect this, and the effect of alternative heart-rate selection methods on score performance is unknown. Methods SCORES was a retrospective within-subject study of consecutive ED patients at a single urban hospital undergoing computed tomography pulmonary angiography (CTPA) for suspected pulmonary embolism (PE). Four SGS variants were calculated using the first, highest, mean, and lowest recorded pre-CTPA heart rate. Outcomes included score output, risk classification, diagnostic performance, reclassification flow, and downstream imaging utilisation. Precision estimates and comparisons were derived using empirical resampling techniques. Results 590 episodes were reviewed with 581 included for analysis. PE was confirmed in 50 cases (8.6%). Mean SGS differed significantly across all heart-rate implementations (p<0.0001). The proportion classified as high risk varied from 15% using the lowest heart rate to 40% using the highest heart rate. Reclassification across the SGS threshold was common, with 25% of episodes changing risk category unidirectionally between lowest and highest heart rate implementations. SGS(lowest HR) compared with SGS(mean HR) and SGS(highest HR) demonstrated higher specificity (87.6% vs 73.4% vs 62.1%), improved AUROC (0.744 vs 0.704 vs 0.659), and reduced downstream CTPA utilisation (818 vs 876 vs 920 scans per 100 PEs diagnosed), with no additional pulmonary emboli missed within the complete diagnostic pathway. Conclusions Heart-rate selection materially influences SGS output, risk classification, diagnostic performance, and imaging utilisation. In this retrospective cohort, use of the lowest recorded heart rate produced the most favourable overall balance of discrimination and diagnostic efficiency, supporting prospective validation.