Combined Mammographic Breast Density and Breast Arterial Calcification as an Incremental Predictor of Coronary Artery Disease

<b><i>Background:</i></b> Contemporary risk calculators underestimate coronary artery disease (CAD) risk in women. Breast arterial calcification (BAC) associates with CAD. Low breast density (BD) (greater breast adipose tissue) associates with cardiometabolic disease. Both are readily identifiable on screening mammography. We sought to evaluate the association between the combined features of BD, BAC, and CAD. <b><i>Methods:</i></b> We retrospectively studied women with clinically indicated mammography and contemporaneous coronary computed tomography angiography. CAD risk was estimated by CAD Consortium Scoring (CCS;>15% high risk). BD was visually assessed by four-level Breast Imaging-Reporting and Data System (BI-RADS) (low:BI-RADS A-B, high:BI-RADS C-D). BAC was visually assessed as present/absent. CAD was categorized as presence/absence of coronary artery plaque. Results are presented with odds ratio (OR) and [95% confidence intervals], and area under the curve (AUC). <b><i>Results:</i></b> In 153 patients (age 62 ± 10), low BD (67%) and BAC presence (24%) were both associated with CAD, respectively: OR: 3.21 [1.58-6.60], <i>p</i> = 0.001, and OR: 4.36 [1.58-12.00], <i>p</i> = 0.004. CAD proportion in low BD (68.9%) and BAC (42.9%) was lower than with combined low BD+BAC positive (89.7%). Compared with (high BD+BAC negative), the presence of (low BD+BAC positive) associated with CAD independent of modifiable (OR: 9.12 [2.44-45.83], <i>p</i> = 0.002) and nonmodifiable (OR: 4.87 [1.22-25.02], <i>p</i> = 0.035) risk factors. CCS >15% was seen in 33%. Significant incremental value was seen with the addition of BD/BAC status to CCS (AUC 0.64 versus 0.73, <i>p</i> = 0.004). <b><i>Conclusions:</i></b> Mammographic BAC and low BD, both alone and combined, associate with CAD, and improve risk prediction beyond standard coronary risk estimation. Standardized reporting of these features may provide benefit and should be tested in prospective screening studies.