Validation of an accelerated high‐sensitivity troponin T assay protocol in an Australian cohort with chest pain

Objectives: To validate an accelerated biomarker strategy using a high‐sensitivity cardiac troponin T (hs‐cTnT) assay for diagnosing acute myocardial infarction (AMI) in patients presenting to the emergency department with chest pain; and to validate this strategy in combination with the National Heart Foundation of Australia/Cardiac Society of Australia and New Zealand risk stratification model. Design, setting and patients: Single‐centre, prospective, observational cohort study of 764 adults presenting to a tertiary hospital with symptoms of possible acute coronary syndrome between November 2008 and February 2011. Main outcome measures: AMI or cardiac death within 24 hours of presentation (primary), and major adverse cardiac events within 30 days (secondary). Results: An elevated hs‐cTnT assay result above the 99th percentile at either the 0 h or 2 h time points had sensitivity of 96.4% (95% CI, 87.9%–99.0%), specificity of 82.6% (95% CI, 79.7%–85.2%), negative predictive value of 99.7% (95% CI, 98.8%–99.9%) and positive predictive value of 30.5% (95% CI, 24.2%–37.6%) for diagnosing AMI. Compared with a traditional 6 h cardiac troponin testing strategy, the accelerated strategy led to reclassification of risk in only two patients with adverse cardiac outcomes, with no net effect on appropriate management. Conclusions: In patients presenting with chest pain, an accelerated biomarker strategy using the hs‐cTnT assay performed well in the initial diagnosis of AMI. The accelerated strategy was also effective when incorporated into a comprehensive strategy of risk stratification that included clinical and demographic factors. The time saved by this approach could have a major impact on health service delivery. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN126153022.