Abstract 12535: Associations Between Apolipoprotein (b) and Lipoprotein (a) With Coronary Calcium Scoring

Introduction: Apolipoprotein B (ApoB) and Lipoprotein a (Lpa) are emerging as important markers of coronary artery disease (CAD). In subjects without documented CAD, we assessed the association between ApoB and Lpa with coronary artery calcium scoring (CACS). Methods: We included 5324 subjects (age 57±8 years ,76% male & 87% white) referred for CACS in a primary prevention clinic between 3/2016 and 10/2021. 10-year multiethnic study on subclinical atherosclerosis CACS (MESA-CACS) risk score was calculated as 0, 1-4.99, 5-9.99 and >10%. ApoB (mg/dl) was divided into <104, 104-127 and >127, while Lpa (mg/dl) was divided into≤40 and >40. Additionally, Lpa was divided based on 60, 70 and 90 mg/dl cutoffs. Results: ApoB was significantly associated with MESA-CAC risk score (p<0.001); while Lpa had a borderline association (Table) (p=0.09). A significantly higher proportion of subjects with normal ApoB were in 0 MESA-CACS risk category (87%), with no difference in other risk categories (Figure 1A). Almost 25% patients with 0 MESA-CACS had Lpa of >40, with no significant difference between normal vs. elevated Lpa across MESA-CACS categories (Figure 1B). No significant difference was noted among the MESA-CACS categories with p-values of 0.284, 0.672 and 0.392 for Lpa cutoffs of 60, 70 and 90 mg/dl respectively. Despite a CACS of 0, 793 (15%) subjects had Lpa>40, while 690 (13%) had a CACS >75th percentile despite Lpa≤40. Conclusions: ApoB was significantly associated with MESA-CACS score, while Lpa only showed a weak association. Hence the addition of Lpa could add synergistic value to CACS in atherogenic risk. stratification Fig1 Distribution of ApoB (A) and Lpa(B) across MESA-CACS groups