Identifying low-risk chest pain in out-of-hours primary care: the diagnostic performance of preHEAR and preHEART scores based on two European cohorts

Abstract Background Distinguishing cardiac from non-cardiac acute chest pain presents a diagnostic challenge. Risk stratification tools, such as the HEART score, have been developed for decision support for hospital-based settings. For prehospital settings, the preHEART score was developed as an alternative to the HEART score, with refinements made to meet prehospital conditions, as illustrated in Figure 1. While promising for use by emergency medical services, the diagnostic performance in primary care is unknown. Purpose In this study, we aim to evaluate the preHEART score (with and without high-sensitivity cardiac troponin (hs-cTn)) as a risk stratification tool to rule out acute myocardial infarction (MI) in patients evaluated in out-of-hours primary care. Methods We relied on retrospective data from two cohorts, namely, the OUT-ACS study involving 1,711 consecutive patients (47.7% female, median age: 56 (25th-75th percentiles: 45-68)) evaluated at a Norwegian primary care emergency centre from 2016-2018; and the TRACE study involving 664 consecutive patients (56.9% female, median age: 48 (25th-75th percentiles: 32-67) from a Dutch primary care emergency centre in 2017. We evaluated the preHEAR (OUT-ACS & TRACE without hs-cTn) and preHEART scores (OUT-ACS). The threshold of ≤3 points was considered low-risk and previously determined as optimal for rule-out purposes. The primary outcome was the diagnostic performance for ruling out MI at the index episode, and the secondary outcome was the composite of 90-day all-cause death or MI. Results In the OUT-ACS cohort, 61 (3.6%) patients were diagnosed with an MI; for the TRACE study, MI was diagnosed in 20 (3.0%) patients. The percentage of patients deemed at low risk by preHEAR was 49.3% (n=843) and 82.7% (n=549) for OUT-ACS and TRACE, respectively. For preHEART, only 33.6% (n=575) of OUT-ACS patients were deemed low-risk. As shown in Figure 2, the corresponding sensitivity/specificity indices for index MI were 63.9%/49.8% (OUT-ACS) and 65.0%/84.2% (TRACE) for preHEAR and 93.4%/34.6% for preHEART. Positive predictive values were low (preHEAR 5.0-11.3%, preHEART 5.0%), whereas negative predictive values were high (preHEAR 97.4-98.7%, preHEART 99.3%). For the secondary outcome, similar diagnostic performance metrics were found. All missed MI cases (n=4) in the low-risk preHEART group were female. Conclusion The preHEAR and preHEART scores did not result in adequate rule-out safety for an emergency primary care setting despite a low a priori MI risk. Moreover, the score appears to underestimate the risk for MI in females.preHEAR(T) risk scoresPerformance of the risk scores