Use of historical high-sensitivity cardiac troponin T levels to rule out myocardial infarction

OBJECTIVE: Several high-sensitivity cardiac troponin (hs-cTn)-based strategies exist for rule-out of myocardial infarction (MI). It is unknown whether historical hs-cTnT concentrations can be used. This study aim to evaluate the performance of a rule-out strategy based on the European Society of Cardiology (ESC) 0/1-hour algorithm, using historical hs-cTnT concentrations. METHODS: All visits among patients with chest pain in the emergency department at nine different hospitals in Sweden from 2012 to 2016 were eligible (221 490 visits). We enrolled patients with a 0-hour hs-cTnT of <12 ng/L, a second hs-cTnT measured within 3.5 hours, and ≥1 historical hs-cTnT available. We calculated the risks of MI and all-cause mortality using two rule-out strategies: (1) a delta hs-cTnT of <3 ng/L between the 0-hour hs-cTnT and the second hs-cTnT (modified ESC algorithm) and (2) a historical hs-cTnT <12 ng/L and a delta hs-cTnT of <3 ng/L in relation to the 0-hour hs-cTnT (historical-hs-cTnT algorithm). RESULTS: A total of 8432 patients were included, of whom 84 (1.0%) had an MI. The modified ESC algorithm triaged 8100 (96%) patients toward ruled-out, for whom 30-day MI risk and negative predictive value (NPV) for MI (95% CI) were 0.4% (0.3% to 0.6%) and 99.6% (99.4% to 99.7%), respectively. The historical-hs-cTnT algorithm ruled out 6700 (80%) patients, with a 30-day MI risk of 0.5% (0.4% to 0.8%) and NPV of 99.5% (99.2% to 99.6%). CONCLUSIONS: The application of algorithm resulted in similar MI risk and NPV to an established algorithm. The usefulness of historical hs-cTnT concentrations should merit further attention.