Assessment of the Diagnostic Accuracy and Reliability of the HEART Score Calculated by Ambulance Nurses Versus Emergency Physicians

Abstract

Chest pain is a common complaint for consultation of emergency medical services worldwide. Currently, ambulance nurses (AN) base their decision to transport a patient to the hospital on their own professional experience. The HEART score could improve prehospital risk stratification and patient treatment. The aim of this study is to investigate the interrater reliability and predictive accuracy of the HEART score between AN and emergency physicians (EP). A retrospective analysis on data of 569 patients 18 years and older included in two prehospital HEART score studies. The endpoints are interrater reliability (intraclass correlation [ICC]) and predictive accuracy for major adverse cardiac events within 30 days of the HEART score calculated by AN versus EP. Predictive accuracy is sensitivity, specificity, positive predicted value (PPV) and negative predicted value (NPV). Interrater reliability was good for total HEART score (ICC 0.78; 95% CI 0.75–0.81). However, focusing on the decision to transport a patient, the ICC dropped to 0.62 (95% CI 0.62–0.70). History and Risk factors caused the most variability. Predictive accuracy of HEART differed between AN and EP. The HEART score calculated by AN was sensitivity 91%, specificity 38%, PPV 26%, and NPV 95%. The HEART score calculated by EP was sensitivity 98%, specificity 32%, PPV −26%, and NPV 99%. With a cut-off value of 0–2 for a low HEART score, predictive accuracy significantly improved for the HEART score calculated by AN: sensitivity 98%, specificity 18%, PPV 22%, and NPV 98%. Our study shows a moderate interrater reliability and lower predictive accuracy of a HEART score calculated by AN versus EP. AN underestimate the risk of patients with acute chest pain, with the largest discrepancies in the elements History and Risk factors. Reconsidering the cut-off values of the low-risk HEART category, as well as a carefully developed training program, will possibly lead to a higher interrater reliability of the HEART score and higher predictive accuracy used by AN.