Low Prevalence of Epicardial CAD Observed in Black Patients Despite Higher CV Risk

Michael T. Lu, MD, MPH

Although race and ethnicity are often studied as risk factors in cardiovascular disease, there are unknowns regarding differences between Black and White individuals undergoing noninvasive testing for coronary artery disease (CAD).

A recent study assessed the differences between self-reported Black and White patients in cardiovascular risk burden, major adverse cardiac events (MACE), and in individuals assigned to receive coronary computed tomography angiography (CCTA) or functional testing for stable chest pain.

Led by Michael T. Lu, MD, MPH, Cardiovascular Imaging Research Center, Massachusetts General Hospital, Harvard Medical School, study investigators observed lower rates of coronary artery calcium, stenosis, and high-risk plaque observed via CCTA in Black patients, despite a greater cardiovascular risk burden.

The Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE) trial randomized 10,003 outpatients with suspected obstructive CAD to either functional testing or antoma testing via CCTA in 193 North American outpatient community and academic health centers.

Enrollment for PROMISE occurred between July 2020 - September 2013, while the analysis was conducted from February 2015 - November 2021.

Data on demographic characteristics, symptoms, cardiovascular risk factors, Framingham Risk Score, and 2013 atherosclerotic cardiovascular disease risk score were collected at enrollment. Additionally, socioeconomic status on education level, health insurance coverage, and income were obtained from the US Census Bureau and matched with each patient’s PROMISE site from 2015 - 2019.

Primary outcomes were considered MACE and defined as the composite end point of death, myocardial infarction, or hospitalization for unstable angina, over a median follow-up of 24.4 months.

A total of 1071 Black (60.3% women; mean age, 59 years), and 7693 White participants (52.4% women; mean age, 61.1 years) were included in the analysis. Data show Black participants had significantly higher body mass index (32.3 versus 30.4, P <.001), more hypertension (82.6% versus 62.6%, P <.001), and diabetes (32.2% versus 18.4%, P <.001).

The mean number of reported cardiovascular risk factors per patient was overall higher in Black patients (2.47 versus 2.35, P <.001).

However, there was no significant difference observed in the rate of MACE during a median follow-up of 24.4 months (32, 3.0% versus 243, 3.2%; P = .84). Following adjustment for age, sex, BMI, and risk factors, there was no statistically significant higher rate of MACE observed in Black patients (HR, 1.00; 95% CI, 0.69 = 1.46, P = .51).

Further, the sensitivity analyses was restricted to the majority of participants with normal or mildly abnormal anatomic or functional testing (79.8%, 6993 of 8764), with an observed lower MACE rate (2.2%, 156 of 6993) over a median follow-up of 24.4 months compared to the overall population. The results were similar in a population not receiving statin therapy (54.3%, 4559 of 8396).

In the CCTA arm of the PROMISE study (n = 3323), significant coronary stenosis (HR, 7.21; 95% CI, 1.94 - 26.76 versus HR, 4.30; 95% CI, 2.62 - 7.04) and high-risk plaque (HR, 3.47; 95% CI, 1.00 - 12.06 versus HR, 2.21; 95% CI, 1.37 - 3.57) showed associations with MACE in both Black and White patients.

But, investigators noted Black patients had a less-prevalent coronary artery calcium score >0 (45.1% versus 63.2%, P <.001), coronary stenosis ≥50% (32, 9.7% versus 430, 14.6%, P = .001) and high-risk plaque (139, 37.6% versus 1547, 52.4, P <.001).

“In a contemporary population of outpatients having noninvasive testing for suspected CAD, we found that Black participants had a higher cardiovascular risk burden but less-prevalent epicardial CAD on CCTA compared with White participants,” investigators wrote.

The study, “Differences in Cardiovascular Risk, Coronary Artery Disease, and Cardiac Events Between Black and White Individuals Enrolled in the PROMISE Trial,” was published in JAMA Cardiology.