Background Troponin assays have evolved and become increasingly sensitive. The prognostic value of identifying small elevations of plasma troponin concentrations in patients with suspected acute coronary syndrome remains uncertain.

Methods We performed a retrospective observational study of 1038 consecutive patients admitted with suspected acute coronary syndrome during the validation of a sensitive troponin I assay. Patients were stratified into three groups based on plasma troponin concentrations: <0.05, 0.05–0.19 and ≥0.20 ng/ml. During this validation phase, only concentrations above the previous diagnostic threshold of ≥0.20 ng/ml were reported to clinicians.

Results Plasma troponin concentrations were <0.05 ng/ml in 657 (63%), 0.05–0.19 ng/ml in 90 (9%) and ≥0.20 ng/ml in 291 (28%) patients. In comparison to patients with a troponin concentration ≥0.20 ng/ml, those with a concentration of 0.05–0.19 ng/ml were less likely to be referred to a cardiologist (44 vs 93%), to receive dual anti-platelet therapy (27 vs 80%), or to undergo coronary revascularisation (17 vs 59%) (p<0.001 for all). At 1 year, patients with troponin concentrations of 0.05–0.19 ng/ml had worse clinical outcomes than patients with troponin concentration of <0.05 ng/ml or ≥0.20 ng/ml (Abstract 47 Figure 1; p<0.001).

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Abstract 47 Figure 1

Conclusions In patients with suspected acute coronary syndrome, use of a sensitive troponin assay markedly increases the incidence of myocardial infarction and identifies those at high-risk of reinfarction and death. Its use will lead to major changes in practice with the potential for reduced morbidity and mortality.