Optimizing early rule-out strategies for acute myocardial infarction

BACKGROUND: Combined testing of high-sensitivity cardiac troponin T (hs-cTnT) and copeptin at presentation provides a very high - although still imperfect - negative predictive value (NPV) for the early rule-out of acute myocardial infarction (AMI). We hypothesized that a second copeptin measurement at 1 h might further increase the NPV. METHODS: In a prospective diagnostic multicenter study, we measured hs-cTnT and copeptin concentrations at presentation and at 1 h in 1439 unselected patients presenting to the emergency department with suspected AMI. The final diagnosis was adjudicated by 2 independent cardiologists blinded to copeptin concentrations. We investigated the incremental value of 1-h copeptin in the rule-out setting (0-h hs-cTnT negative and 0-h copeptin negative) and the intermediate-risk setting (0-h hs-cTnT negative and 0-h copeptin positive). RESULTS: The adjudicated diagnosis was AMI in 267 patients (18.6%). For measurements obtained at presentation, the NPV in the rule-out setting was 98.6% (95% CI, 97.4%-99.3%). Whereas 1-h copeptin did not increase the NPV significantly, 1-h hs-cTnT did, to 99.6% (95% CI, 98.7%-99.9%, P = 0.008). Similarly, in the intermediate-risk setting (NPV 92.8%, 95% CI, 88.7%-95.8%), 1-h copeptin did not significantly increase the NPV (P = 0.751), but 1-h hs-cTnT did, to 98.6 (95% CI, 96%-99.7%, P < 0.001). CONCLUSIONS: One-hour copeptin increased neither the safety of the rule-out process nor the NPV in the intermediate-risk setting. In contrast, the incremental value of 1-h hs-cTnT was substantial in both settings.