Abstract 13387: Highly Sensitive Troponin I and Coronary Computed Tomography Angiography Assessment of Stenosis and High-risk Plaque Permit Rapid Classification of Acute Coronary Syndrome Risk in Chest Pain Patients: Results from the ROMICAT II Trial

Abstract

Introduction: Highly sensitive troponin (hsTn) and coronary computed tomography angiography (CCTA) are promising diagnostic tools for triage of acute chest pain patients in the emergency department (ED). We determined whether a diagnostic strategy of initial hsTn I followed by early CCTA improves classification of ACS risk. Methods: We included ED patients with acute chest pain, negative electrocardiogram and conventional troponin who were enrolled in the ROMICAT II trial, randomized to CCTA and had hsTn I (hsVista, Siemens Diagnostics) measured at the time of presentation. The patients were categorized as having hsTn I < the limit of detection (<0.5 pg/mL), > 99th percentile (>49 pg/mL), or intermediate. Core lab readers assessed CCTA for the presence of ≥50% stenosis and high-risk plaque features (positive remodeling, low CT attenuation <30 HU, napkin ring sign, spotty calcium). Results: Overall, 160 patients met inclusion criteria (mean age 53±8 years, 40% women, ACS during index hospitalization 10.6%, n=19). The ACS rate was 0% (n=0/9) for patients with HsTn I < the limit of detection 8.6% (n=12/139) for patients with intermediate HsTn I and 53.8% (n=7/12) for patients with hsTnI > 99th percentile. No coronary plaque was present in 68 (42.5%), non-obstructive CAD in 70 (43.8%), ≥50% stenosis in 22 (13.8%), and high-risk plaque in 61 (38.1%) patients. The figure shows ACS risk stratification based on hsTn I followed by CCTA. The addition of CCTA increased the number of patients categorized as low risk from 9 to 96 and high risk from 12 to 25 and re-classified 63% of patients (n=100). The net gain in reclassification proportion was 0.47 (95%CI 0.16-0.78; p=0.003) for patients with ACS and 0.59 (95%CI 0.46-0.72; p <0.001) for patients without ACS, and net reclassification index was 1.06 (95%CI 0.73-1.40; p <0.001). Conclusions: A strategy of initial hsTn I at the time of ED presentation followed by early CCTA improved classification of ACS risk in patients with acute chest pain.