Study on Elevated Lipoprotein(a) and Coronary Artery Calcium Score

Elevated lipoprotein(a) [Lp(a)] and coronary artery calcium (CAC) score are individually associated with increased atherosclerotic cardiovascular disease (ASCVD) risk. A recent study suggests that a combination of Lp(a) and CAC is also independently associated with ASCVD risk. The study findings were published in the Journal of the American College of Cardiology on February 21, 2022.

While CAC has become a more-routine clinical test, the medical community has not yet embraced Lp(a) in the same way because the question of what to do about an elevated measure remains unanswered. Also, the relationship of Lp(a) to coronary artery calcium (CAC) scores are understudied. Therefore, Dr. Anurag Mehta and his team conducted a study to investigate the independent and joint association of Lp(a) and CAC with ASCVD risk.

In this study, the researchers included 4,512 asymptomatic participants of the MESA study and 2,078 patients from the DHS (Dallas Heart Study). The researchers measured plasma Lp(a) and CAC at enrollment and observed 476 incident atherosclerotic cardiovascular disease (ASCVD) events over 13.2 years follow-up. They determined elevated Lp(a) was defined as the highest race-specific quintile, and 3 CAC score categories were studied (0, 1-99, and ≥100). They evaluated the associations of Lp(a) and CAC with ASCVD risk using risk factor–adjusted Cox regression models.

Key Findings of the Study:

• Upon analysis, the researchers found that elevated Lp(a) and CAC scores (1-99 and ≥100) were independently associated with ASCVD risk (HR: 1.29; HR: 1.68 and HR: 2.66, respectively). However, they observed no interaction of Lp(a)-by-CAC.
• Compared with participants with non-elevated Lp(a) and CAC = 0, they found that those with elevated Lp(a) and CAC ≥100 were at the highest risk (HR: 4.71), and those with elevated Lp(a) and CAC = 0 were at a similar risk (HR: 1.31).
• They observed similar findings when guideline-recommended Lp(a) and CAC thresholds were considered and noted that the findings were replicated in the DHS.

The authors concluded, "Lp(a) and CAC are independently associated with ASCVD risk and may be useful concurrently for guiding primary prevention therapy decisions."

In an accompanying editorial, Dr. Sotirios Tsimikas wrote that this study provides important insights into Lp(a) pathophysiology with CAC, implications for clinical care, and the ability to identify the patients most likely to benefit from Lp(a) lowering. Both Lp(a) and CAC should be more broadly applied in clinical care settings in patients without prior ASCVD to identify those that most likely will benefit from more aggressive therapy and, in the future, from Lp(a)-lowering therapies.

For Further Information:

Mehta A, Vasquez N, et al. Independent association of lipoprotein(a) and coronary artery calcification with atherosclerotic cardiovascular risk. J Am Coll Cardiol. 2022;79:757-768.