Abstract
Background: A limitation of diagnostic algorithms in suspected myocardial infarction (MI) is the requirement for assay-specific high-sensitivity cardiac troponin (hs-cTn) cut-off concentrations and change criteria. We sought to evaluate a common change criteria algorithm (3C) for hs-cTn and compared it to established algorithms for the rule-out and rule-in of MI.
Methods: We applied the 3C algorithm in two prospective cohort studies (with 3 different hs-cTn assays) of patients presenting to the emergency department with suspected MI who had serial hs-cTn results available. Diagnostic performance measures (sensitivity, specificity, predictive values, likelihood ratios) for MI were obtained for both 3C (change criteria >|3| for under 10 ng/L, >|30|% between 10-100 ng/L and >|15|% for above 100 ng/L) and the ESC algorithms for rule-in and rule-out. Confusion matrices, net reclassification improvement (NRI), and effectiveness (percentage rule-in and rule-out) analyses were also performed.
Results: In 5011 patients, the MI prevalence was 16.12% (n=811) . Comparable diagnostic accuracy in terms of sensitivity, specificity, and predictive values were observed between the 3C and ESC algorithms. Direct comparison of the algorithms via NRI showed no decisive advantage for either algorithm. Confusion matrices for all three assays for both 0/1h and 0/2h sampling identified that the 3C ruled-in more patients with a MI who were ruled-out with the ESC. Effectiveness was higher for 3C (83.2-88.8%) versus ESC (64.4-74.5%) for hs-cTnI but not for hs-cTnT (64.5-71.8% versus 72.4-80.6%, respectively).
Conclusions: The 3C algorithm offers a uniform, assay agnostic alternative to established algorithms, independent of timing of serial sampling.
Trial registrations: NCT02355457; ACTRN12611001069943; ANZCTR12610000766011; ANZCTR12613000745741