THE INCIDENCE OF UNSTABLE ANGINA IN PATIENTS WITH LOW HIGH-SENSITIVITY TROPONIN I VALUES: A SUBGROUP ANALYSIS OF THE RACE-IT TRIAL

Document Type

Conference Proceeding

Publication Date

4-1-2024

Publication Title

J Am Coll Cardiol

Keywords

troponin, troponin I, acute coronary syndrome, cardiologist, cohort analysis, conference abstract, coronary angiography, diagnosis, drug therapy, electrocardiogram, electrocardiography, emergency ward, female, heart infarction, human, incidence, major clinical study, male, revascularization, secondary analysis, therapy, unstable angina pectoris

Abstract

Background We sought to identify the incidence of unstable angina in patients with low high-sensitivity cardiac troponin I (hs-cTnI) in Emergency Departments (EDs). Methods This was a preplanned secondary analysis of the Rapid Acute Coronary Syndrome Exclusion using high-sensitivity I cardiac Troponin (RACE-IT) stepped-wedge randomized trial, which compared two rule-out protocols (0/1-hour and 0/3-hour) for myocardial infarction (MI) in 9 EDs from 7/2020-3/2021. A hs-cTnI assay from Beckman Coulter was used (99th percentile 18 ng/L). In the accelerated protocol (AP), MI was excluded if hs-cTnI was <4 ng/L at presentation, or =4 ng/L at presentation with a 1-hour value <8 ng/L. Those that did not rule-out within 1 hour required a 3-hour hs-cTnI ≤18 ng/L to rule-out. In the standard care (SC), MI was excluded if hs-cTnI values were ≤18 ng/L at 0 and 3 hours. Patients were excluded if hs-cTnI was >18 ng/L within 3 hours of presentation. Unstable angina was adjudicated based on the ISCHEMIA trial definition, which required electrocardiographic changes or findings at coronary angiography (ruptured/ulcerated plaque or thrombus). Adjudication was performed by interventional cardiologists for patients undergoing coronary angiography, and by cardiology fellows in patients with hs-cTnI >18 ng/L >3 hours after presentation. Results Of the 32,608 patients in the trial, 58 patients (0.18%) met the definition of unstable angina (35 in the AP and 23 in the SC protocol). In the AP 12/35 (34.3%) patients with unstable angina had a presenting hs-cTnI <4 ng/L. In the AP, among patients who ruledout for MI within 1 hour, 13/10444 (0.12%) had unstable angina vs. 22/8659 (0.25%) among those who did not meet early rule-out criteria (adjusted odds ratio 0.73, 95% CI 0.33 - 1.60, p=0.43). Within 30 days there were 113 (0.35%) patients in the entire cohort who had a revascularization procedure and in the unstable angina group there were 38 (65.5%). Conclusion Unstable angina is rare in patients with a low hs-cTnI values at presentation to the ED and few receive revascularization procedures. However, of those ultimately diagnosed with unstable angina in the AP, a substantial portion had an extremely low hs-cTnI at presentation.

Volume

83

Issue

13

First Page

1268

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