Abstract 10337: Adding Natriuretic Peptides to Either Conventional or High-Sensitivity Troponin-T Improves Reclassification of Acute Coronary Syndrome Diagnosis in Emergency Department Patients with Chest Pain: From the ROMICAT Trial
Objective: To evaluate the value of adding natriuretic peptides (myocyte stress markers) to troponins (myocardial injury markers) for diagnosing acute coronary syndrome (ACS) in ED patients with chest pain.
Methods: In 328 patients (53±12 years, 63% men, EF 68±10%) with initially negative conventional troponin-T (cTnT) concentrations and nonischemic ECG, we measured cTnT, high-sensitivity troponin-T (hsTnT), amino-terminal pro-B type natriuretic peptide (NT-proBNP), and mid-regional pro-atrial natriuretic peptide (MR-proANP) at time of 64-slice CT. ACS (n=29, 9%) was defined as either myocardial infarction or unstable angina.
Results: Patients with ACS had higher levels of all 4 biomarkers as compared to those without (cTnT: 0.05 vs 0.0006 ng/mL, hsTnT: 30.5 vs 4.9 pg/mL, NT-proBNP: 100 vs 45 ng/L, MR-proBNP: 83 vs 57 pmol/L; all p<0.01). Adding the natriuretic peptides, especially NT-proBNP, to troponins improved the C-statistics (AUC) and net reclassification index (NRI) for ACS, largely driven by correctly reclassifying events (Table 1). A dual-negative marker result improved sensitivity (cTnT 38% to 83-86%, hsTnt 59% to 86-90%; all p<0.01) and NPV (cTnT 94% to 97-98%, hsTnt 96% to 97-98%) for ACS. Patients with dual-negative markers had the lowest percentage of CT coronary plaque, stenosis (>50% luminal narrowing), and regional wall motion abnormalities (RWMA) (Figure 1, all p-trend<0.001).
Conclusions: Among ED chest pain patients, a dual marker strategy of combining natriuretic peptides to troponins improved discriminatory capacity and allowed for better reclassification of ACS, findings supported by structural and functional cardiac CT results.
- © 2011 by American Heart Association, Inc.