Validation of presentation and 3 h high-sensitivity troponin to rule-in and rule-out acute myocardial infarction

OBJECTIVE: International guidelines to rule-in acute myocardial infarction (AMI) in patients presenting with chest pain to the emergency department (ED) recommend an algorithm using high-sensitivity cardiac troponin (hs-cTn) sampling on presentation and 3 h following presentation. We tested the diagnostic accuracy of this algorithm by pooling data from five distinct cohorts from three countries of prospectively recruited patients with independently adjudicated outcomes. METHOD: We measured high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) on presentation (0 h) and 3 h post-presentation samples in adult patients attending an ED with possible AMI to validate the European Society of Cardiology (ESC) Working Group on Acute Cardiac Care rule-in algorithm (ESC-rule-in). Specifically, (i) in patients with a 0 h hs-cTn concentration ≤99th percentile and a 3 h hs-cTn >99th percentile, positive patients are those with an absolute change in troponin ≥50% of the 99th percentile, and (ii) in patients with a 0 and 3 h hs-cTn >99th percentile, positive patients are those with a relative change in troponin of ≥20%. We concurrently assessed the efficacy of the 0 and 3 h hs-cTn <99th percentile to rule-out AMI. RESULTS: 1061 patients with hs-cTnI and 985 with hs-cTnT were included. The ESC-rule-in positive predictive value (PPV) was 83.5% (95% CI 74.9% to 90.1%) for hs-cTnI and 72.0% (95% CI 62.1% to 80.5%) for hs-cTnT. Forty-six AMIs (34.9%) were not ruled in using hs-cTnI and 62 (46.2%) using hs-cTnT. The sensitivity of the 99th percentile to rule-out AMI was 93.2% (95% CI 87.5% to 96.8%) for hs-cTnI and 94.8% (95% CI 89.5% to 97.9%) for hs-cTnT. CONCLUSIONS: The ESC-rule-in algorithm has good PPV with hs-cTnI and reasonable with hs-cTnT and can rule-in over 50% of AMIs. However, the sensitivity of the 99th percentile to rule-out AMI is too low for clinical use.