Abstract 264: High Serum Lp(a) Levels Are Associated With Subclinical 3-Vessel and Left Main Coronary Disease, Severe Stenoses and Plaque Volume in Apparently Healthy African Americans

Abstract

Background: Serum Lp(a) is a CAD risk factor in European Americans (EA). Levels are 2-3 fold higher in African Americans (AA) but associations with CAD are inconsistent, including coronary calcium. The relationship of race-specific levels of Lp(a) with the extent and severity of subclinical total coronary plaque (TCP) has not been described. Methods: We screened 418 apparently healthy individuals for risk factors and coronary plaque using advanced CTA. TCP volumes (mm3) were quantified using a validated automated method. Lp(a) was measured by ELISA. The association of Lp(a) with plaque was investigated by race. Multivariable modeling was performed with adjustment for traditional CAD risk factors, including LDL-C, and intrafamilial correlations. Results: Mean age was 51±11 years; 57% female; 34% AA. Lp(a) was higher in AA than in EA (median 38 [18,65] vs 17 [10,33], p<0.0001). Plaque was present in 45% of AA and 47% of EA. In those with plaque continuous Lp(a) levels were associated with plaque volume in AA (β=8.83, p<0.0001) but not EA (β=1.49, p=0.45). Lp(a) was strongly associated with plaque extent and severity (Table), and with TCP volume in AA (adjusted p=0.01) but not in EA (p=0.10). In AA, Lp(a)≥60 mg/dL (top quintile) was independently associated with a 3.7 times greater risk of 3-vessel and/or LM disease (95% CI:1.4-10.3), a 6.6 times greater risk of having a stenosis ≥50% (95% CI:1.4-38.4, p=0.02), and higher TCP (median 438 [203,1247] vs 142 [73,262], p=0.001). Conclusion: High Lp(a) is strongly associated with coronary plaque extent, severity, and volume in apparently healthy AA. High levels of Lp(a) may be particularly important in the pathogenesis of CAD in AA.