Risk stratifying chest pain patients in the emergency department using HEART, GRACE and TIMI scores, with a single contemporary troponin result, to predict major adverse cardiac events

Abstract

Background: The majority of patients presenting to the ED with cardiac sounding chest pain have a non-diagnostic ECG and the problem of differentiating those suffering an acute coronary syndrome from those without is familiar to all ED clinical staff. To stratify risk in these patients, specific scores have been developed. Recent work has focused on incorporating newer high-sensitivity cardiac troponin (hs-cTn) assays; however, issues regarding performance and availability of these assays remain.

Aim: Prospectively compare HEART, Global Registry of Acute Coronary Events (GRACE) and Thrombolysis in Myocardial Infarction (TIMI) scores, using a single contemporary cTn at admission, to predict a major adverse cardiac event (MACE) at 30 days.

Method: Prospective observational cohort study performed in a UK tertiary hospital in patients with suspected cardiac chest pain and no significant ST elevation on initial ECG. Data collection took place 2 December 2014 to 8 February 2016. The treating clinician recorded risk score data real time and a single contemporary cTn taken at presentation was used in score calculation. The primary endpoint was 30-day MACE. C-statistic was determined for each score and diagnostic characteristics of high-risk and low-risk cut-offs were calculated.

Results: 189/1000 patients in the study developed a 30-day MACE. The c-statistic of HEART for 30-day MACE (0.87 (95% CI 0.84 to 0.90)) was higher than TIMI (0.78 (95% CI 0.74 to 0.81)) and GRACE (0.74 (95% CI 0.70 to 0.78)).HEART score ≤3 identified low-risk patients with sensitivity 99.5% (95% CI 97.1% to 99.9%) and negative predictive value (NPV) 99.6% (95% CI 97.3% to 99.9%) exceeding TIMI 0 (sensitivity 97.4% (95% CI 93.9% to 99.1%) and NPV 97.8% (95% CI 94.8% to 99.1%)) and GRACE score 0-55 (sensitivity 95.2% (95% CI 91.1% to 97.8%) and NPV 95.8% (95% CI 92.2% to 97.7%)).

Conclusion: HEART outperformed both TIMI and GRACE in overall discriminative capacity for 30-day MACE. Using a single contemporary cTn at presentation, a HEART score of ≤3 demonstrated sensitivity and NPV of ≥99.5% for 30-day MACE. These results reach the threshold for a safe discharge strategy but should be interpreted thoughtfully in light of other work.

Keywords: acute coronary syndrome; acute myocardial infarct; cardiac care, diagnosis; emergency department; risk management.