Lipoprotein (a) and risk for calcification of the coronary arteries, mitral valve, and thoracic aorta: The Multi-Ethnic Study of Atherosclerosis

Background: Lipoprotein (a) [Lp(a)] is a risk factor for coronary heart disease and calcific aortic valve disease. We determined the relationships of Lp(a) with prevalence and progression of coronary artery calcification (CAC), mitral annular calcification (MAC), and thoracic aortic calcification (TAC) in a multi-ethnic cohort of middle to older-aged adults. Methods: This analysis included 6705 Multi-Ethnic Study of Atherosclerosis participants. Lp(a) was measured with a turbidimetric immunoassay. CAC, MAC, and TAC were assessed by cardiac computed tomography both at baseline and once during follow-up. Results: In adjusted relative risk regression cross-sectional analysis, a Lp(a) level ≥50 ​mg/dL was associated with a 22% higher prevalence of MAC (relative risk (RR) ​= ​1.22, 95% confidence interval (CI) 1.00, 1.49). No significant associations were observed for prevalent CAC or TAC. In adjusted prospective analyses, participants with Lp(a) ≥50 ​mg/dL were at significantly higher risk for rapid CAC progression (median follow-up ​= ​8.9 years), defined as ≥100 units/year, compared to those with lower Lp(a) levels (RR ​= ​1.67, 95% CI ​= ​1.23, 2.27). The association between higher Lp(a) levels and incident CHD was no longer significant after adjusting for CAC progression. No significant associations were observed for MAC or TAC progression (median follow-up ​= ​2.6 years). Conclusions: Higher Lp(a) levels are associated with more rapid CAC progression. Additional study is needed to better understand how this relationship can further improve the ability of Lp(a) to enhance cardiovascular disease risk prediction.