Noise versus signal: the clinical implications of an increasingly sensitive troponin assay for patients with suspected acute coronary syndrome.

OBJECTIVES: To evaluate the clinical impact of a troponin assay switch in suspected acute coronary syndromes (ACS). METHODS: Retrospective analysis of ACS cases in the 3 months before and after changing to a contemporary, higher sensitivity troponin assay. Admitting diagnosis, proportion with a positive result, initial treatment and testing, coronary artery intervention, inhospital events, and final discharge diagnosis were compared by assay group. RESULTS: Seven hundred seventy patients were included: 319 (41.4%) preassay and 451 (58.6%) postassay. Preassay change, non-ST segment elevation myocardial infarction at admission (43.0% vs. 70.5%; diff [95% confidence interval (CI)] = -27.5 [-34.2, -20.6]) was diagnosed less often, and a positive troponin was less common (33.2% vs. 72.3%; diff [95% CI] = -39.1 [-45.4, -32.2]). However, anticoagulation (53.3% vs. 42.4%; diff [95% CI] = 10.9 [3.8, 18.0]) and cardiac catheterization use were more frequent (53.9% vs. 41.9%; diff [95% CI] = 12.0 [19.0, 48.5]). There was no difference in coronary intervention (41.9% vs. 40.7%; diff [95% CI] = 1.2 [-9.0, 11.2]) by assay period. Inhospital event were rare (unstable ventricular arrhythmia = 1.2%, cardiac arrest = 3.4%, death = 4.4%) with no difference between groups. A non-ACS diagnosis at discharge was more common in the postassay group (31.6% vs. 46.5%; diff [95% CI] = 14.9 [7.9, 21.6]). CONCLUSIONS: Although non-ST segment elevation myocardial infarction diagnosis at admission and a positive troponin were more frequent postassay change, rates of anticoagulation and cardiac catheterization were lower and a non-ACS diagnosis at discharge was more common. These data suggest an evolving understanding and clinical impact of contemporary troponin assays when used in real-world settings.

Duke Scholars

Author John David Purakal Emergency Medicine