A study published in a recent issue of the New England Journal of Medicine (NEJM) provides new evidence that lipoprotein (a) – or Lp(a) – could be a useful predictor of risk of stroke among older men. Lp(a) has been known to be associated with heart disease although the actual role it plays is still not clear. The association with stroke adds a new dimension to the nature of risk associated with Lp(a) and its role in vascular diseases.

Lp(a) is a modification of the low-density lipoprotein (LDL) molecule that contributes to atherosclerosis, in which plaques of cholesterol and lipids collect on the interior walls of arteries, restricting blood flow. Although still not commonly ordered, tests to measure blood levels of Lp(a) are used, along with lipid profiles, to screen for risk factors for coronary artery disease and cerebral vascular disease. Since about 50% of people who suffer heart attacks have normal cholesterol levels, medical professionals are starting to look at other factors, like elevated Lp(a), that may influence the processes behind these conditions.

In the NEJM study by the Cardiovascular Health Study Investigators (led by Dr. Abraham Ariyo of the Center for Cardiovascular Disease Prevention and Intervention, HeartMasters, in Dallas and the Division of Cardiology at Johns Hopkins Hospital in Baltimore), high levels of Lp(a) were associated with increased risk of stroke among male patients. The study followed 5,888 men and women aged 65 and older for 7 years. The results indicated that the men with the highest levels of Lp(a) in the study sample had three times the risk of stroke, nearly three times the risk of death from cardiovascular disease, and almost twice the risk of death from all causes compared to those men with lower baseline Lp(a) levels. However, no such findings were observed for the women in the study.

These results led the investigators to conclude that among older men in the U.S., elevated Lp(a) is an independent predictor of stroke as well as death from vascular disease and that this supports the use of Lp(a) to predict risk of these events. There remains concern that the role of Lp(a) is still not fully understood. Further study is needed before widespread testing of Lp(a) levels will be recommended for older patients.

Nevertheless, with this new study, the use of Lp(a) for predicting heart disease and stroke in high risk patients is likely to increase in cases where other predictors are inconclusive.