Abstract 981: High-Sensitivity Troponin Reliably Excludes Acute Coronary Syndrome in Patients with Acute Chest Pain: Results from the Rule Out Myocardial Infarction by Computed Tomography (ROMICAT) Study
Objective: To evaluate a new high sensitivity (hs) troponin T assay in patients with acute chest pain and low to intermediate risk for acute coronary syndrome (ACS).
Methods: We included consecutive patients who presented with acute chest pain to the emergency department (ED) and had a negative initial troponin T test (Elecsys, 4th Generation, detection limit 0.01 ng/ml, 10% imprecision) and a normal or nondiagnostic ECG on admission. In all patients hs troponin T (Roche GmbH, cut-off 13 pg/ml, 99th percentile taken from 1500 apparently healthy subjects [unpublished results]; imprecision 10%) and further serial standard troponin T measurements were performed. The occurrence of ACS was adjudicated by experienced clinicians using standard AHA/ACC criteria. Univariate and multivariable regression analyses (adjusted for age, gender, smoking, history of diabetes, HDL and LDL cholesterol, statin intake, and TIMI score) were carried out to assess the predictive value of hs troponin for ACS.
Results: Among 377 patients (mean age 53 ± 11.8 yrs; female 135, 35.8%), ACS occurred in 37 patients (10%: 27 unstable angina, 10 NSTEMI). Hs troponin T concentrations were significantly higher in patients with ACS compared to those without (median, interquartile range: 28.0, 8.6 – 68.7 pg/ml vs 5.0, 2.6 – 8.1 pg/ml, p<0.0001). In age- and gender- adjusted analysis, patients in the highest tertile of hs toponin T had an almost 5-fold increased odds for ACS when compared to the lowest tertile (Odds Ratio [OR] 4.9; 95% confidence interval [CI], 2.1–11.4). This association was only moderately attenuated in multivariable adjusted analysis (3.8; 95%CI, 1.6–9.2). Using the 99th percentile of the hs troponin T distribution as a cutpoint, ORs were 9.3 (95% CI, 4.2–20.5) and 8.4 (95% CI, 3.5–20.0), respectively. For this cut-off, sensitivity, specificity, PPV and NPV were 62.2%, 88.9%, 37.7% and 95.6%, respectively.
Conclusions: Hs troponin T is an independent predictor for ACS in patients with acute chest pain. A 99th percentile cutoff provides excellent NPV with acceptable PPV for ACS, including unstable angina. Further studies performing serial testing are needed to confirm the clinical utility of hs troponin assays.