Interplay of Risk Factors and Coronary Artery Calcium for CHD Risk in Young Patients

Objectives: The aim of this study was to examine prevalence, predictors, and impact of coronary artery calcium (CAC) across different risk factor burdens on the prevalence of obstructive coronary artery disease (CAD) and future coronary heart disease (CHD) risk in young patients.

Background: The interplay of risk factors and CAC for predicting CHD in young patients aged ≤45 years is not clear.

Methods: The study included 3,691 symptomatic patients (18-45 years of age) from the WDHR (Western Denmark Heart Registry) undergoing coronary computed tomographic angiography. CHD events were myocardial infarction and late revascularization.

Results: During a median of 4.1 years of follow-up, 57 first-time CHD events occurred. In total, 3,180 patients (86.1%) had CAC = 0 and 511 patients (13.9%) had CAC >0. Presence of CAC increased with number of risk factors (odds ratio: 4.5 [95% CI: 2.7-7.3] in patients with >3 vs 0 risk factors). The prevalence of obstructive CAD at baseline and the rate of future CHD events increased in a stepwise manner with both higher CAC and number of risk factors. The CHD event rate was lowest at 0.5 (95% CI: 0.1-3.6) per 1,000 person-years in patients with 0 risk factors and CAC = 0. Among patients with >3 risk factors, the event rate was 3.1 (95% CI: 1.0-9.7) in patients with CAC = 0 compared with 36.3 (95% CI: 17.3-76.1) in patients with CAC >10.

Conclusions: In young patients, there is a strong interplay between CAC and risk factors for predicting the presence of obstructive CAD and for future CHD risk. In the presence of risk factors, even a low CAC score is a high-risk marker. These results demonstrate the importance of assessing risk factors and CAC simultaneously when assessing risk in young patients.