Usefulness of a single measurement of high-sensitivity troponin T to rule out acute myocardial infarction, acute coronary syndrome or death by any cause in patients admitted to the thoracic pain unit

Abstract

Background: High-sensitivity troponin has represented a breakthrough in the evaluation of patients with suspected acute myocardial infarction. Recent single-center and retrospective studies suggest that acute myocardial infarction (AMI) could be immediately excluded in patients with initial low levels of high-sensitivity troponin T (hs-cTnT) and nonischemic ECG, with no need of serial sampling. Objective: The aim of this study was to evaluate the sensitivity and specificity of different cut-off points of an initial value of hs-cTnT for predicting AMI, acute coronary syndrome and cardiovascular death within 30 days of the consultation. Methods: We performed a prospective study including patients with chest pain and nonischemic ECG. Blood drawn on arrival was tested for hs-cTnT (Roche, 99th percentile 14ng/L, Limit of detection 5ng/L) and 3 hours later. The primary outcome was AMI, acute coronary syndrome and death during the first 30 days. Results: We included 811 patients with a median age of 58.9 ± 14.2 years. 16.2% of patients were diabetic, and 20.8% had previous history of infarction. 20.4% of patients were hospitalized after the first consultations, while the rest of them were discharged. Follow-up was achieved for 99% of patients, having a 7.8% rate of AMI, 14.6% of acute coronary syndrome and 1.5% of deaths. The ROC curve was 0.919 for AMI, 0.724 for acute coronary syndrome and 0.904 for death. The highest cutoff point to avoid an event was ≤ 5 for infarction (negative predictive value, NPV:100 %), < 3 for acute coronary syndrome (NPV:96 %) and ≤ 14 for death (NPV:100%). Results: In the absence of signs of ischemia on an electrocardiogram, different cutoff points are needed to exclude AMI, acute coronary syndrome or cardiovascular death.