Trends in Use of Biomarker Protocols for the Evaluation of Possible Myocardial Infarction

BACKGROUND: Various combinations of creatine kinase‐MB, myoglobin, and cardiac troponin I or T (cTnI/cTnT) have been used to evaluate patients with suspected acute coronary syndromes. The current recommendation is to use the 99th percentile of cTnI/cTnT as the sole marker for diagnosis of acute myocardial infarction. METHODS AND RESULTS: We retrospectively analyzed cardiac marker protocols collected from 824 US hospitals undergoing Chest Pain Center Accreditation through the Society of Cardiovascular Patient Care from 2009 to 2014. Data were obtained by a self‐reported survey that addressed cardiac marker(s), sampling time periods, and cut points used for evaluation of suspected acute myocardial infarction. The combination of cTnI or cTnT with creatine kinase‐MB was the most commonly used biomarker strategy. Use of cTnI or cTnT as the sole marker increased over time (14–37%; P<0.0001), as did use of the 99th percentile cut point for cTnI/cTnT (30–60%; P<0.0001). CONCLUSION: There is considerable variation in cardiac marker testing strategies used in US hospitals for evaluation of suspected acute myocardial infarction. Although increasing, 24% of hospitals used a cTn alone strategy, and only 49% used cTn at the recommended 99th percentile cut point. This has important implications for the diagnosis and treatment of patients with acute myocardial infarction.