Research studies discover enhancements in clinical methods to better diagnose coronary artery disease in Asian population

Singapore, 25 August 2022 – Coronary Artery Disease (CAD) is the most common form of heart disease, accounting for about 20% of local deaths¹. Two research studies by NHCS looked into data that are unique to the Asian population and discovered two distinct methods which can potentially improve the prediction of CAD in our local community. The findings of these studies were recently published in leading peer-reviewed scientific journals.

Multi-centre study develops patented novel analytical method for local community

Generally, patients suspected to have CAD will undergo several diagnostic tests to accurately diagnose the disease, including an invasive coronary angiogram (ICA) which is the current gold standard in assessing and diagnosing CAD. ICA involves injecting dye (contrast material) into the patient and then using x-rays to see how blood flows through the coronary arteries. During ICA, fractional flow reserve (FFR) is used to measure blood pressure within a coronary artery, which can determine the functional significance of coronary artery stenosis (i.e. the degree of narrowing of the coronary artery influences blood flow and can lead to a heart attack).

Over 100 patients who had undergone non-invasive CT coronary angiogram (CTCA), ICA and invasive FFR were recruited in this multi-centre research study.² Led by Associate Professor Zhong Liang, Principal Investigator, National Heart Research Institute Singapore (NHRIS), NHCS, the team experimented a novel analytical method of measuring blood pressure within a coronary artery – using 3-dimensional (3-D) models reconstructed from these patients’ CTCA images, and analysed the data of both the invasive and non-invasive tests. Refer to Annex 1 for illustration.

“Through the study, we demonstrated that this novel analytic method from non-invasive CTCA images and computational method, delivers comparable accuracy of determining the blood pressure within the coronary arteries, to current invasive diagnostic tests. This could potentially reduce invasive angiography, enhance patient safety and management as patients can opt for this non-invasive method instead,” said Assoc Prof Zhong Liang.

This novel method has been granted a patent³ by the United States Patent and Trademark Office and is currently undergoing further trial for potential clinical application in the near future.

Improved pre-test probability model tailored to mixed Asian population

Chest pain is a common symptom presented in patients with stable CAD. A guideline-recommended pre-test probability (PTP) score is a tool used by doctors to assess stable chest pain and guide their decisions on the next appropriate test and further management of the patient. The US and European guidelines recommend the use of various models and a variety of PTP scores such as the CAD Consortium 2 (CAD2) model.

Computerised Tomography (CT)-based coronary artery calcium scores measure the amount of calcium in the arteries (built-up plaque) and is a well-established predictor of the likelihood of CAD and risk of future heart attacks. It is included in recent PTP scores validated for the Western population.

 “As the guidelines are validated for the Western population, the performance of these tools may vary when applied to the local Asian population due to differing ethnic group compositions and geographical locations,” shared Dr Lohendran Baskaran, Senior Consultant, NHCS. “Some studies have shown these scores tend to overestimate the prediction of CAD in Asians leading to unnecessary investigations and treatments.”

Therefore, the research study⁴ led by Dr Baskaran aimed to evaluate the effectiveness of the PTP score, specifically the CAD2 model as well as the inclusion of CT-based coronary artery calcium scores in predicting obstructive CAD in patients with stable chest pain in a mixed ethnic cohort in Singapore. The study which analysed over 500 patients’ scores for CAD showed that the incorporation of CT-based coronary artery calcium scores in the CAD2 model significantly improved the prediction of CAD. Tailored calibration to the local population further enhanced the model’s performance.

“The findings affirmed the role of CT-based coronary artery calcium scoring in CAD2 model in assessing CAD in Asian population and the need to customise these tools in our local context.  This could aid in guiding further downstream investigations to determine if further tests are indeed required,” said Dr Baskaran, “thus enhancing patient care and management, and potentially saving costs and resources.”

References:

1. Ministry of Health: https://www.moh.gov.sg/resources-statistics/singapore-health-facts/principal-causes-of-death
2. Zhang JM, Han H, Tan RS, et al. Diagnostic performance of fractional flow reserve from CT coronary angiography with analytical method. Front Cardiovasc Med 2021;8:739633. Doi:10.3389/cvm.2021.739633.
3. Zhong L, et al. US patent number 10,636,146. Medical image processing methods and systems. 
4. Baskaran L., Neo YP., Lee JK., et al. Evaluating the Coronary Artery Disease Consortium Model and the Coronary Artery Calcium Score in Predicting Obstructive Coronary Artery Disease in a Symptomatic Mixed Asian Cohort. J Am Heart Assoc 2022;11(8):e022697. Doi: 10.1161/JAHA.121.022697.

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About the National Heart Centre Singapore

The National Heart Centre Singapore (NHCS) is a 185-bed national and regional referral centre for cardiovascular diseases. NHCS provides a one-stop comprehensive cardiac care ranging from preventive, diagnostic, therapeutic to rehabilitative services. It is also the only heart and lung transplantation centre in Singapore.

Each year, NHCS handles over 120,000 outpatient consultations, 9,000 interventional and surgical procedures and 10,000 inpatients. Its clinical outcomes for heart attack treatment, balloon angioplasty with stenting and coronary bypass surgery have been shown to be equivalent to international benchmarks.

Established in 1998, NHCS is the pioneer in cardiovascular care in Singapore.

For more information, please visit www.nhcs.com.sg.