This study tracked elevated levels of Lipoprotein(a) over the course of 16 years, and the findings suggest that current cholesterol-lowering medications may not be effective at reducing the risk of recurrent CHD due to elevated levels of Lp(a) in older adults.
“This finding adds to growing evidence of a relationship between increased Lp(a) and the risk of recurrent CHD,” says lead author Associate Professor Leon Simons, from the School of Clinical Medicine, at the University of New South Wales Sydney. “It is well-established that people who have already experienced CHD are at very high risk of another event. Our new results indicate that new therapeutics in development that aim to reduce elevated Lp(a) might help prevent recurrent disease. However, the potential clinical benefit of therapy to reduce elevated Lp(a) is yet to be confirmed.”
Cholesterol travels through the blood on lipoproteins (LDL, Lp(a), and HDL) which are made of fat and protein. Low-density lipoprotein (LDL) is often called bad cholesterol because it tends to collect in blood vessel walls increasing the risk for developing cardiovascular diseases. A person may be able to maintain levels within a healthy range with lifestyle changes and/or modifications, or with medications such as statins.
Previous research indicates that high levels of Lp(a) are a risk factor in the development of CHD, but most of this work looks at these levels and the risk of the first CHD event. This study was designed to investigate whether elevated Lp(a) levels are predictive of recurrent CHD events.
This study involved 607 participants over the age of 60 years old, who all had prevalent CHD, and were followed for 16 years as part of the Dubbo study. During the study period, there were 399 reported incident CHD cases.
The researchers reported that the median Lp(a) in those who had a recurrent CHD event was 130 mg/L, compared to 105 mg/L in those who did not; 26% of those who had a recurrent CHD event, and 19% of those who did not, had Lp(a) levels greater than 300 mg/L; and 18% of those who had a recurrent CHD event, and 8% of those who did not, had Lp(a) levels of greater than 500 mg/L. In those with prior CHD, elevated levels in the top 20% (>355 mg/L)predicted a 53% increased risk of a recurrent CHD event compared to those in the lowest 20% (<50 mg/L) over the 16-year follow-up, and this prediction was independent of other risk factors.
“We conclude that elevated Lp(a) is an important predictor of recurrent CHD in older people. Upper reference Lp(a) levels of 500 mg/L or 300 mg/L both appear to be appropriate for identifying those at higher risk who may benefit from more intensive risk reduction interventions,” says Associate Professor Simons. “While current medications, such as statins, are often prescribed to lower ‘bad cholesterol’ in patients at higher risk of cardiovascular disease, these do not have any major or proven impact on elevated Lp(a). But there is hope for the future – as some novel therapeutics that are designed to lower the levels of Lp(a) are currently in the advanced stages of clinical development.”
