Pre-hospital versus hospital acquired HEART score for risk classification of suspected non ST-elevation acute coronary syndrome

Abstract

Introduction: Although increasing evidence shows that in patients with suspected non-ST-elevation acute coronary syndrome (NSTE-ACS) both hospital and pre-hospital acquired HEART (History, ECG, Age, Risk factors, Troponin) scores have strong predictive value, pre-hospital and hospital acquired HEART scores have never been compared directly.

Methods: In patients with suspected NSTE-ACS, the HEART score was independently prospectively assessed in the pre-hospital setting by ambulance paramedics and in the hospital by physicians. The hospital HEART score was considered the gold standard. Low-risk (HEART score ≤3) was considered a negative test. Endpoint was occurrence of major adverse events within 45 days.

Results: A total of 699 patients were included in the analyses. In 516 (74%) patients pre-hospital and hospital risk classification was similar, in 50 (7%) pre-hospital risk classification was false negative (45 days mortality 0%) and in 133 (19%) false positive (45 days mortality 1.5%). False negative risk classifications were caused by differences in history (100%), risk factor assessment (66%) and troponin (18%) and were more common in older patients. Occurrence of major adverse events was comparable in pre-hospital and hospital low-risk patients (2.9% vs. 2.7%, p = 0.9). Incidence of major adverse events was 0% in the true negative group, 26% in the true positive group, 10% in the false negative group and 5% in the false positive group. Predictive value of both pre-hospital and hospital acquired HEART scores was high, although the 'area under the curve' of hospital acquired HEART score was higher (0.84 vs. 0.74, p < 0.001).

Conclusion: In approximately 25% of patients hospital and pre-hospital HEART score risk classifications disagree, mainly by risk overestimation in the pre-hospital group. Since disagreement is primarily caused by different scoring of history and risk factors, additional training may improve pre-hospital scoring.

Keywords: HEART score; NSTE-ACS; Paramedics.