Two- vs three-hour hs-cTnI algorithms for ruling out acute myocardial infarction using the Beckman access high-sensitivity cardiac troponin I: a systematic review

Background: Patients with symptoms of acute coronary syndrome make up a significant proportion of emergency department (EDs) presentations. High-sensitivity troponin testing is a standard component of evaluating patients with suspected symptomatic coronary disease. We sought to synthesize the evidence of the accuracy of 0/2-h and 0/3-h algorithms using the Beckman Access high-sensitivity cardiac troponin I (hs-cTnI) assay. Methods: We developed an electronic search strategy retrieving research from three electronic databases (Medline, Embase, and Wiley Cochrane Library). Relevant research studies were screened and data extracted by a team of reviewers. Study quality and risk assessment were appraised using the QUADAS-2 tool. Findings were reported according to PRISMA guidelines. Results: Five studies met inclusion criteria. No studies directly compared the 0 h/2 h and 0 h/3 h algorithms using the Beckman Coulter Access hs-cTnI assay, and heterogeneity in study design precluded meta-analysis. Included studies variably used 2-h, 3-h, or intermediate timepoints for serial troponin measurement. All studies reported consistently high sensitivity (> 97.7%) and NPV (> 98.9%) for ruling out acute myocardial infarction, supporting the reliability of both 0/2 h and 0/3 h hs-cTnI algorithms in the ED. Conclusions: Of the five studies included, two studies suggest that a two-hour hs-TnI algorithm can effectively rule out myocardial infarction with similar accuracy to a longer three-hour protocol. Use of a 2-h hs-cTnI algorithm may lead to operational gains compared to a 3-h serial testing algorithm.