Hogan, Christopher

Background Cardiac troponin (cTn) can be elevated in many patients presenting to the emergency department (ED) with chest pain but without a diagnosis of acute coronary syndrome (ACS). We compared the prognostic significance of cTn in these different populations. Methods We retrospectively analyzed the CHOPIN study, which enrolled patients who presented to the ED with chest pain. Patients were grouped as ACS, non-ACS cardiovascular disease, noncardiac chest pain and chest pain not otherwise specified (NOS). We examined the prognostic ability of cTnI for the clinical endpoints of mortality and major adverse cardiovascular event (MACE; a composite of acute myocardial infarction, unstable angina, revascularization, reinfarction, and congestive heart failure and stroke) at 180-day follow-up. Results Among 1982 patients analyzed, 14% had ACS, 21% had non-ACS cardiovascular disease, 31% had a noncardiac diagnosis and 34% had chest pain NOS. cTnI elevation above the 99th percentile was observed in 52, 18, 6 and 7% in these groups, respectively. cTnI elevation was associated with mortality and MACE, and their relationships were more prominent in noncardiac diagnosis and chest pain NOS than in ACS and non-ACS cardiovascular diagnoses for mortality, and in non-ACS patients than in ACS patients for MACE (hazard ratio for doubling of cTnI 1.85, 2.05, 8.26 and 4.14, respectively; P for interaction 0.011 for mortality; 1.04, 1.23, 1.54 and 1.42, respectively; P for interaction <0.001 for MACE). Conclusion In patients presenting to the ED with chest pain, cTnI elevation was associated with a worse prognosis in non-ACS patients than in ACS patients.

Introduction: Copeptin has demonstrated a role in early rule out for acute myocardial infarction in combination with a negative troponin. However, the value of copeptin in patients with a positive troponin is not established. Hypothesis: The addition of a baseline copeptin at chest pain presentation will improve risk stratification in patients with mild troponin elevation. Methods: The multi-center CHOPIN trial enrolled 2071 acute chest pain patients. All subjects with ST segment elevations were excluded from this analysis. Of the remaining patients, 124 had a mildly elevated troponin (defined by < 2x URL) and were included in the study cohort. Baseline cTnI and copeptin levels were drawn on presentation, and another cTnI at 2 hours. Copeptin ≤14 pmol/l and troponin deltas ≤10% from baseline were considered positive. Two independent blinded cardiologists adjudicated AMI diagnosis. The value of a baseline copeptin in this cohort was assessed using AMI incidence, odds ratio, sensitivity, and negative predictive value (NPV). Results: Of the 124 patients in the study cohort, 73 (59%) had an elevated copeptin and an associated AMI incidence of 25% (18 AMIs). The remaining 51 patients (41%) were copeptin negative and diagnosed with 3 AMIs, an incidence of 5.9% (p = 0.006, figure 1). A positive copeptin increased the likelihood of AMI diagnosis with an odds ratio of 5.3 (95% CI: 1.5-19.2). The sensitivity and NPV for AMI were 86% and 94%, both of which were higher than the delta troponin (table 1). When an initial copeptin was combined with the delta troponin the sensitivity and NPV for AMI improved to 100%. Conclusion: Use of copeptin in chest pain patients with mild troponin elevation provides further risk stratification. The combination of copeptin with a delta troponin may aid in earlier AMI rule out in this subset of patients. This approach could be especially relevant as the increasing use of high sensitivity troponin assays leads to greater rates of mild troponin elevations.