Discrete non-calcified plaque is associated with increased major adverse cardiovascular events in a high cardiovascular risk population with low coronary artery calcium scores (0-100).

Background: Patients with coronary artery calcium (CAC) scores of 0-100 and non-calcified plaque (NCP) on coronary computed tomography angiography (CCTA) have traditionally been considered low risk for obstructive coronary artery disease (CAD) and future adverse cardiovascular events (CVEs). In regions with high pre-test probability for CAD and negative social determinants of health, rates of adverse CVEs remain higher than in lower-risk populations.

Methods: A retrospective review from January 2019 to May 2022 of 1050 symptomatic patients without known CAD and a CAC score of 0-100 identified 385 patients (37 ​%) with discrete NCP and 665 patients (63 ​%) without NCP on CCTA. The study's primary endpoint was to identify predictors of discrete NCP presence and future adverse CVEs (death, non-ST and ST-elevation myocardial infarction, or cerebrovascular accident) within two years.

Results: A logistic regression analysis showed the presence of discrete NCP in patients with a CAC score of 0-100 was significantly associated with hyperlipidemia (OR 1.556, 95 ​% CI [1.145-2.115], p ​< ​0.005), diabetes mellitus (OR 1.475, 95 ​% CI [1.043-2.085], p ​< ​0.028), tobacco use disorder (OR 1.372, 95 ​% CI [1.028-1.830], p ​< ​0.032), older age (OR 1.035, 95 ​% CI [1.022-1.048], p ​< ​0.001), elevated systolic blood pressure (OR 1.020, 95 ​% CI [1.011-1.028], p ​< ​0.001), and higher total CAC score (OR 1.013 95 ​% CI [1.007-1.020], p ​< ​0.001). Patients with NCP had higher cardiac risk scores (ASCVD and Morise score) and were more likely to live in rural communities (0-5000 people) (p ​< ​0.005). They also had higher rates of coronary angiography, non-ST and ST-elevation myocardial infarctions, and coronary artery bypass grafting at two years (p ​< ​0.001). The presence of discrete NCP remained an independent predictor for future adverse CVEs after adjusting for diabetes mellitus, systolic blood pressure, hyperlipidemia, total CAC score, age, female sex, body mass index, and community population size (aOR 1.882, 95 ​% CI [1.048-3.380], p ​< ​0.034). Patients with discrete NCP had a 5.70 ​% adverse CVE rate.

Conclusion: High rates of discrete NCP (37 ​%) and subsequent adverse CVEs were observed in our symptomatic, high cardiovascular risk population with CAC scores of 0-100. The presence of discrete NCP on CCTA was an independent risk factor for future adverse CVEs. Our findings emphasize the need for a more comprehensive approach to cardiovascular risk assessment in these vulnerable groups.