Investigation of the Biomarker Copeptin in Patients With Acute Myocardial Infarction (CHOPIN)

In patients with symptoms suggestive of acute coronary syndrome (ACS) such as chest pain or pressure, shortness of breath, diaphoresis, and nausea, detection of a rise and/or fall of troponin with at least one value above the 99th percentile of the upper reference limit is essential to the diagnosis of acute myocardial infarction (AMI). However, current troponin testing has limitations, including antibody specificity, assay imprecision, lack of standardization and a relatively late increase in the circulating troponin level after the onset of ischemia. Studies have shown a low diagnostic sensitivity of troponins when measured early (<6 hours) after symptom onset. Although there are some more sensitive troponin assays with a coefficient of variation (CV)10% at the 99th percentile of a normal reference population, most troponin assays have an imprecision CV of around 20% at the 99th percentile of the reference population. The early insensitivity of troponin results in an unmet need in the clinical evaluation of patients presenting with suspected ACS and AMI.

Copeptin may improve early AMI diagnostic sensitivity because of a number of unique characteristics.

• Copeptin levels are elevated at presentation in patients with AMI compared to patients with other presentations.
• Copeptin levels are elevated in patients with AMI even when troponin levels were not elevated at the time of initial presentation.
• Thus, a combination of troponin and copeptin levels at presentation may result in a more accurate diagnosis of acute AMI than troponin alone.
• Copeptin levels drop 1 day after an AMI.