Incidence and Outcomes of Unstable Angina in Patients with Low High-Sensitivity Cardiac Troponin I Values-A Substudy of the RACE-IT Trial

Authors

• Raef Fadel, Henry Ford HealthFollow
• Joseph B. Miller, Henry Ford HealthFollow
• Bernard Cook, Henry Ford HealthFollow
• Felix Nguyen, Henry Ford HealthFollow
• Mohammad Alqarqaz, Henry Ford HealthFollow
• Brittany S. Fuller, Henry Ford HealthFollow
• Mir B. Basir, Henry Ford HealthFollow
• Tiberio M. Frisoli, Henry Ford HealthFollow
• Pedro Villablanca, Henry Ford HealthFollow
• Ahmad Jabri, Henry Ford HealthFollow
• Khaldoon Alaswad, Henry Ford HealthFollow
• Akshay KhandelwalFollow
• Natesh Lingam, Henry Ford HealthFollow
• Brian O’Neill, Henry Ford HealthFollow
• Henry Kim, Henry Ford HealthFollow
• Pedro Engel Gonzalez, Henry Ford HealthFollow
• Elizabeth Pielsticker, Henry Ford HealthFollow
• Gerald C. Koenig, Henry Ford HealthFollow
• Seth Krupp, Henry Ford HealthFollow
• Nicholas L Mills
• Simon Mahler
• Phillip Levy, Henry Ford Health
• Benjamin Brennan, Henry Ford HealthFollow
• Shane P. Bole, Henry Ford HealthFollow
• Sachin Parikh, Henry Ford HealthFollow
• Khaled Abdul-Nour, Henry Ford HealthFollow
• Michael Hudson, Henry Ford HealthFollow
• Bryan Zweig, Henry Ford HealthFollow
• Omr Abuzahrieh, Henry Ford HealthFollow
• Chaun Gondolfo, Henry Ford Health
• James McCord, Henry Ford HealthFollow

Recommended Citation

Fadel R, Miller J, Cook B, Nguyen F, Alqarqaz M, Fuller B, Basir MB, Frisoli T, Villablanca P, Jabri A, Alaswad K, Khandelwal A, Lingam N, O’Neill B, Kim H, Gonzalez PE, Pielsticker E, Koenig G, Krupp S, Mills NL, Mahler S, Levy P, Brennan B, Bole S, Parikh S, Nour K, Hudson M, Zweig B, Abuzahrieh O, Gondolfo C, McCord J. Incidence and Outcomes of Unstable Angina in Patients with Low High-Sensitivity Cardiac Troponin I Values-A Substudy of the RACE-IT Trial. J Clin Med. 2026;15(9).

Document Type

Article

Publication Date

4-23-2026

Publication Title

J Clin Med

Abstract

Background: Unstable angina has become an exceedingly rare diagnosis in the era of high-sensitivity cardiac troponin (hs-cTn). Objectives: We sought to identify the incidence of unstable angina and characterize patients with low hs-cTn in emergency departments (EDs). Methods: A prespecified secondary analysis of the Rapid Acute Coronary Syndrome Exclusion using high-sensitivity cardiac Troponin I (RACE-IT) trial was conducted. RACE-IT was a stepped-wedge randomized trial comparing two rule-out protocols (0/1- and 0/3 h) for myocardial infarction (MI) in nine EDs from July 2020 to April 2021. All patients had hs-cTnI (Beckman Coulter) concentrations below or equal to the 99^th percentile upper reference limit of 18 ng/L. The primary outcome was unstable angina, based on the ISCHEMIA trial definition, which required electrocardiographic changes or findings at coronary angiography (angiographic evidence of plaque rupture or thrombus). Results: Of the 32,608 patients in the trial, 60 patients (0.2%) met the definition of unstable angina, of whom 46 (77%) had obstructive disease at coronary angiography and 17 (28%) had an ischemic electrocardiogram. Coronary revascularization was performed in 45 (75%) patients and seven (12%) had left main or 3-vessel coronary artery disease. There were seven (12%) patients with non-obstructive coronary artery disease, and seven (12%) who had angiographically unremarkable coronary arteries. Patients with unstable angina were older (p = 0.015), more likely to be male (p = 0.005), with a higher prevalence of hypertension (p < 0.001), known coronary artery disease (p < 0.001), peripheral vascular disease (p = 0.035), and a higher serum creatinine (p = 0.018). At 30 days, two patients had a type 1 MI and there were no deaths. Conclusions: Unstable angina was diagnosed in 1 in 500 patients with a low hs-cTnI value at presentation to the ED and these patients had an excellent prognosis at 30 days. These patients tend not to have high-risk anatomy and one in four had non-obstructive coronary artery disease or angiographically unremarkable coronary arteries.

PubMed ID

42122941

Volume

15

Issue

9