Multicenter analysis to assess risk of major adverse cardiac events in patients undergoing high-sensitivity troponin testing in the emergency department.

Study Hypothesis: Our objective was to evaluate 30-day major adverse cardiac events (MACE) in emergency department (ED) patients with normal high-sensitivity troponins (hs-trop). We hypothesized that MACE rates would be <1% in patients with (1) two normal troponins regardless of change in troponin (delta) and (2) index hs-trop below the limit of quantitation (LOQ) regardless of the institution modified HEART score.

Methods: This was a multicenter, retrospective, cohort study of adult patients who presented to 1 of 18 EDs between July 2020 and April 2021 with acute coronary syndrome as defined by an institutional-modified HEART score completed by their treating physician or midlevel, no evidence of ST-elevation myocardial infarction, and an index or serial gender-adjusted hs-trop within normal limits. The primary outcome was MACE within 30 days of index ED encounter. A detailed case review was then performed for those patients experiencing a MACE.

Results: Of the 9084 patients who had single or serial normal troponins, 31 (0.34%; confidence interval [CI] 0.23%-0.48%) experienced MACE. Of the 6140 patients with 2 normal hs-trop and a delta (change in troponin) <4, 27 patients (0.44%; CI 0.29%-0.64%) experienced MACE. Only 1 of the 69 patients with 2 normal hs-trop results but delta (change in troponin) ≥ 4 (1.45%; CI 0.04%-7.81%) suffered MACE. This patient was classified as non-low risk by our institutional HEART score. Of 7498 patients with an index hs-trop 
Conclusion: Patients with 2 normal hs-trop values in the ED are unlikely to suffer 30-day MACE. Although it remains unclear whether patients with delta (change in troponin) ≥4 despite normal troponins will have a 30-day MACE, this situation is rare. Additionally, a single index hs-trop <6 ng/L demonstrated a low risk for 30-day MACE independent of the institutional HEART score.