hs-Troponin I Followed by CT Angiography Improves Acute Coronary Syndrome Risk Stratification Accuracy and Work-Up in Acute Chest Pain Patients: Results From ROMICAT II Trial

Abstract

Objectives: This study compared diagnostic accuracy of conventional troponin/traditional coronary artery disease (CAD) assessment and highly sensitive troponin (hsTn) I/advanced CAD assessment for acute coronary syndrome (ACS) during the index hospitalization.

Background: hsTnI and advanced assessment of CAD using coronary computed tomography angiography (CTA) are promising candidates to improve the accuracy of emergency department evaluation of patients with suspected ACS.

Methods: We performed an observational cohort study in patients with suspected ACS enrolled in the ROMICAT II (Rule Out Myocardial Infarction/Ischemia using Computer Assisted Tomography) trial and randomized to coronary CTA who also had hsTnI measurement at the time of the emergency department presentation. We assessed coronary CTA for traditional (no CAD, nonobstructive CAD, ≥50% stenosis) and advanced features of CAD (≥50% stenosis, high-risk plaque features: positive remodeling, low <30-Hounsfield units plaque, napkin-ring sign, spotty calcium).

Results: Of 160 patients (mean age: 53 ± 8 years, 40% women) 10.6% were diagnosed with ACS. The ACS rate in patients with hsTnI below the limit of detection (n = 9, 5.6%), intermediate (n = 139, 86.9%), and above the 99th percentile (n = 12, 7.5%) was 0%, 8.6%, and 58.3%, respectively. Absence of ≥50% stenosis and high-risk plaque ruled out ACS in patients with intermediate hsTnI (n = 87, 54.4%; ACS rate 0%), whereas patients with both ≥50% stenosis and high-risk plaque were at high risk (n = 13, 8.1%; ACS rate 69.2%) and patients with either ≥50% stenosis or high-risk plaque were at intermediate risk for ACS (n = 39, 24.4%; ACS rate 7.7%). hsTnI/advanced coronary CTA assessment significantly improved the diagnostic accuracy for ACS as compared to conventional troponin/traditional coronary CTA (area under the curve 0.84, 95% confidence interval [CI]: 0.80 to .88 vs. 0.74, 95% CI: 0.70 to 0.78; p < 0.001).

Conclusions: hsTnI at the time of presentation followed by early advanced coronary CTA assessment improves the risk stratification and diagnostic accuracy for ACS as compared to conventional troponin and traditional coronary CTA assessment. (Multicenter Study to Rule Out Myocardial Infarction/Ischemia by Cardiac Computed Tomography [ROMICAT-II]; NCT01084239).

Keywords: acute coronary syndrome; coronary computed tomography angiography; coronary plaque; emergency department; highly sensitive troponin; risk stratification.

Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Study population enrollment, exclusion and inclusion

CONSORT diagram shows the inclusion and exclusion of patients resulting in the final study population of 160 patients.

Figure 2. High-risk plaque features as detected by coronary CTA

Panel A – low CT attenuation

Figure 3. Traditional coronary CTA assessment and ACS in the ROMICAT II trial

Flow diagram depicts the risk stratification based on the conventional troponin followed by the traditional assessment of coronary CTA for the presence of coronary atherosclerotic plaque and ≥50% stenosis.

Figure 4. Combined HsTn I and advanced coronary CTA assessment and ACS in the ROMICAT II trial

Flow diagram depicts the improvement of ACS risk stratification using hsTn I at the time of ED presentation. Further improvement of the risk stratification can be achieved with advanced assessment of coronary CTA for high-risk plaque.