Observational Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Dec 26, 2021; 13(12): 745-757
Published online Dec 26, 2021. doi: 10.4330/wjc.v13.i12.745
Highly sensitive troponin I assay in the diagnosis of coronary artery disease in patients with suspected stable angina
Indra Ramasamy
Indra Ramasamy, Department of Biochemistry, Worcester Royal Hospital, Worcester WR5 1DD, United Kingdom
Author contributions: Ramasamy I was responsible for the conception, design and analysis and presentation of the data and writing the manuscript.
Institutional review board statement: The study was carried out according to the Declaration of Helsinki and the NHS Data Protection Act. The study was approved by the Research and Ethics Committee of the Worcester Acute Hospitals NHS Trust.
Conflict-of-interest statement: The author has no competing interest to declare.
Data sharing statement: The raw data is stored in the Laboratory Quality Management System of The Worcester Royal Hospital, and is available following anonymization of patient identifiable information. The full data set can be requested from the corresponding author upon approval of the paper proposal using the data.
STROBE statement: The authors have read the STROBE Statement, and the manuscript was prepared and revised according to the STROBE Statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Indra Ramasamy, MSc, PhD, Senior Researcher, Department of Biochemistry, Worcester Royal Hospital, Charles Hastings Way Worcester WR5 1DD, Worcester WR5 1DD, United Kingdom. indrar@ozemail.com.au
Received: August 20, 2021
Peer-review started: August 26, 2021
First decision: October 17, 2021
Revised: October 23, 2021
Accepted: December 3, 2021
Article in press: December 3, 2021
Published online: December 26, 2021
Processing time: 124 Days and 15.9 Hours
Abstract
BACKGROUND

Evaluation of suspected stable angina patients with probable coronary artery disease (CAD) in the community is challenging. In the United Kingdom, patients with suspected stable angina are referred by community physicians to be assessed by specialists within the hospital system in rapid access chest pain clinics (RACPC). The role of a highly sensitive troponin I (uscTnI) assay in the diagnosis of suspected CAD in a RACPC in a “real-life” setting in a non-academic hospital has not been explored.

AIM

To examine the diagnostic value of uscTnI (detection limit 0.12 ng/L, upper reference range 8.15 ng/L, and detected uscTnI in 96.8% of the reference population), in the evaluation of stable CAD in a non-selected patient group, with several co-morbidities, who presented to the RACPC.

METHODS

One hundred and seventy two RACPC patients were assigned to either functional or anatomical testing according to the hospital protocol.

RESULTS

The investigations offered to patients were exercise tolerance test 7.6%, 24 h ECG 1.2%, Echocardiogram 14.5%, stress echocardiogram 8.1%, coronary computed tomography angiography (CCTA) 12.8%, coronary angiogram 13.4%, 17.4% were diagnosed with non-cardiac chest pain, 3.5% treated as stable angina, 8.2% reviewed by cardiologists, electronic medical records were not available in 10.4%. Receiver operating characteristic curves for CAD used uscTnI values measured in patients who underwent functional testing, angiogram or CCTA. Values > 0.52 ng/L showed 100% sensitivity and at > 11.6 ng/L showed 100% specificity. In the range > 0.52-11.6 ng/L, uscTnI may not have the same diagnostic potential. In patients assigned to coronary angiogram higher concentrations of uscTnI was associated with severe CAD. Low levels of uscTnI and low pre-test probability of CAD (QRISK3) may decrease patient numbers assigned to CCTA.

CONCLUSION

The uscTnI diagnostic cut-off values in a RACPC will depend on patient population and their presenting co-morbidity. In the presence of clinical comorbidities and previous CAD the uscTnI needs to be used in conjunction with clinical assessment.

Keywords: Rapid access chest pain clinic; Suspected stable angina; Troponin I; Coronary artery disease; Coronary angiogram; Coronary computed tomography angiography

Core Tip: In the United Kingdom, patients with suspected stable angina are referred to rapid access chest pain clinic (RACPC) by community physicians for assessment by hospital specialist medical practitioners. We evaluated the value of a new highly sensitive cardiac troponin I assay in the management of patients with suspected coronary artery disease (CAD) in a RACPC. Patients admitted for further assessment and preselected for either coronary computed tomography angiography or coronary angiogram the assay may indicate the severity of CAD. The diagnostic cut-off values of the assay is determined by the patient population and existing co-morbidities.