NEW ORLEANS – Coronary artery calcium (CaC) scoring was less reliable as a screen for atherosclerotic plaque for people of certain races and countries, according to the large international study GPS-CAD.
From a real-world imaging database covering more than 32,000 individuals and 15 countries on six continents, it was clear that race/ethnicity and country – considered together as a single surrogate measure for ancestry and environment – was the strongest single predictor of CAC findings, including true positivity, where CAC >0 and coronary CT angiogram (CCTA) no plaque (AUC 0.62) and was positive for false negative, where CAC = 0 but CCTA was positive (AUC 0.64).
According to Lohendran Baskaran, MBBS, of the National Heart Center Singapore, false-negative CAC=0 can be predicted based on country (particularly prevalent in Egypt, Peru, Canada, Pakistan, Japan, India), race/ethnicity (Middle Eastern, Asian, and black groups), and age (individuals <55 years).
“In patients with suspected atherosclerotic CAD, race/ethnicity, country, and age should be considered in decision making regarding the use of CAC or CCTA and in the interpretation of CAC (score) = 0 findings,” they said at the annual meeting of the American College of Cardiology (ACC).
Indeed, CAC scans measure the amount of calcified plaque in coronary arteries, and have previously been shown to disappear early non-calcified atherosclerotic lesions that are evident on CCTA.
The GPS-CAD investigators had a large group of people for their study who had undergone CCTA and CAC scans to rule out atherosclerotic coronary artery disease (CAD). There were 55% who had CAC >0 and 60% who had any stenosis detected on CCTA.
The majority of patients were true positive (53.1%, CAC+, CCTA+) or true negative (38.2%, CAC-, CCTA-). A minority had false negatives (7.0%, CAC-, CCTA+) and, to an even lesser extent, false positives (1.4%, CAC+, CCTA-).
“I was struck by the fact that only 7% of patients with a score of zero had any non-calcified plaque,” commented ACC session panelist Matthew Budoff, MD, of UCLA Medical Center in Los Angeles, although this “obviously varied significantly by race and ethnicity.”
Budoff cited the support of CAC scoring in the recent US lipid guideline update as part of decision making when initiating lipid-lowering therapy in adults at intermediate risk and selecting adults at borderline risk without prior atherosclerotic cardiovascular disease (Class I).
“Now that we have these new cholesterol guidelines from just a week ago … I think this very low prevalence of calcified plaque volume of these patients with zero (CAC) scores across all different races and ethnicities really helps solidify the potential use of that tool,” Budoff said.
“I think anytime we can look at a population spanning so many countries and so many patients, over 32,000 patients, it really helps us understand the epidemiology of many of these diseases. I think (GPSCAD) strongly reinforces what we would consider the power of (CAC=0),” he emphasized.
GPSCAD relies on an aggregated dataset composed of data obtained from clinical registries, databases, randomized control trials, and observational studies.
The overall mean age of participants was 59 years, 45% were women, and 73% were symptomatic. By race and ethnicity, this group was 39% non-Hispanic/Latino White, 29% Hispanic/Latino White, 5% Black, 20% Asian, and 4% Middle Eastern.
CAD with at least 50% stenosis was ultimately detected on CCTA in 18%.
Bhaskaran said gender, symptomatic status and diabetes status had no apparent effect on the likelihood of a false negative CAC scan.
The design and rationale paper of the GPS-CAD study was published simultaneously JACC:Asia.
Bhaskaran told the ACC room that the study is still welcoming more contributors and group collaborators in its quest to inform pre-trial prospects for CAC in specific ethnic groups (for example, South Asians and Southeast Asians versus East Asians).
“This comprehensive and representative dataset provides an essential foundation for developing robust, generalizable (prior probability) models that take into account global ethnic and geographic variations. The geographic distribution of study sites achieves broad global coverage, with increased representation of historically underrepresented regions,” according to Junjie Yang, MD, and Ran Xin, MD, of the Chinese PLA General Hospital in Beijing.
“The era of globalization in health care has begun, and its pace is irreversible,” the two wrote. an accompanying editorial. “It is expected that GPSCAD studies will make significant contributions to global CAD risk assessment in the (artificial intelligence) era.”
