Early diagnosis of acute myocardial infarction in patients with mild elevations of cardiac troponin

Background The early diagnosis of acute myocardial infarction (AMI) in patients with mild elevations of high-sensitivity cardiac troponin (hs-cTn) is a challenge. It is unclear whether copeptin, a marker of endogenous stress, or 1h-hs-cTn changes are better suited to address this important unmet clinical need. Methods We prospectively enrolled patients presenting with symptoms suggestive of AMI to the emergency department (ED). Two independent cardiologists adjudicated the final diagnosis. Mild hs-cTn elevations were defined as 26.2 ng/L (99th percentile) to 75 ng/L for hs-cTnI, and 14 ng/L (99th percentile) to 50 ng/L (biological-equivalent to 75 ng/L for hs-cTnI) for hs-cTnT. Results Among 1356 patients, 80 (6%) had mild hs-cTnI elevations at presentation. Within this group, AMI was the final diagnosis in 39 patients (49%). The diagnostic accuracy for the diagnosis of AMI as quantified by the area under the receiver operating characteristic curve (AUC) was 0.51 (95% CI 0.39–0.64) for hs-cTnI at presentation, 0.58 (95% CI 0.45–0.71) for copeptin at presentation, and 0.78 (95% CI 0.68–0.88) for 1h-hs-cTnI changes, which was significantly higher as compared to copeptin ( p = 0.02) or hs-cTnI alone ( p