Chest pain with less than 20% change in high sensitivity troponin T - a low risk cohort?

Background: Patients with chest pain are risk-stratified using serial high-sensitivity troponin (T) assays (hsTnT). Those with change in (Δ)hsTnT <20% are often categorised as low-risk and are less likely to be managed as acute coronary syndromes (ACS). We sought to characterise such a population of 'low-risk' chest pain presenters.Methods: We performed a retrospective cohort analysis of sequential patients admitted to our centre over a 1-year period with chest pain, absence of ST-elevation, with elevated hsTnT concentrations, and compared demographic, clinical and outcome data according to ΔhsTnT.Results: Three hundred and eleven patients were subdivided by ΔhsTnT [<20% (n = 80), 20-100% (n = 78), >100% (n = 153)]. Baseline demographic data were well-matched across the three subgroups; atrial fibrillation was more common in the two lower magnitude ΔhsTnT groups. Obstructive coronary artery disease (CAD) - while less common in those with ΔhsTnT <20% (66.2%) compared to the 20-100% (73.1%) and >100% (75.9%) groups (p = 0.03) - remained high in this lower risk group, and indeed revascularisation occurred in >60% of patients, equally frequently in all three groups. Using absolute ΔhsTnT ≥9ng/L within the ΔhsTnT <20% group provided incremental value in ruling in ACS, with a positive predictive value of 74.1%. ΔhsTnT was a univariate but not a multivariate predictor of obstructive CAD.Conclusions: Obstructive CAD and need for revascularisation are frequent in chest pain presenters with ΔhsTnT <20%. The increasing focus on hsTnT algorithms to exclude ACS and promote early discharge without adequate clinical risk stratification modelling risks misdiagnosis of patients presenting with acute myocardial ischaemia with a low-level hsTnT rise.