It’s not a popular type of cholesterol like the “good” and “bad” kinds we test for. But it may be linked to the third leading cause of heart disease in the country. Lp(a) is a protein that sits on the LDL particle, the one that carries so-called “bad” cholesterol. It appears that Lp(a) is causally linked to aortic stenosis, a valve disease affecting 1.5 million Americans.
The link between Lp(a) and aortic stenosis
Patients are typically not screened for Lp(a) levels, but those with a common genetic variant for Lp(a) have a 60 percent greater risk of developing aortic calcifications than others, according to a new study in published in the New England Journal of Medicine.
Study results support
the need to intensify
lipid management in
patients with elevated
“It is interesting that Lp(a), a lipoprotein known to be associated with increased risk for premature cardiac risks like heart attacks, is now linked to an increased risk for development of aortic valve stenosis,” says Stanley Hazen, MD, PhD, Section Head of Preventive Cardiology and Rehabilitation at Cleveland Clinic.
Aortic stenosis is when the main valve regulating blood flow between the heart and the rest of the body is critically narrowed. Symptoms include fainting, heart attack or early death. Surgery can correct the disease.
Additional research on Lp(a)
An increase in cardiac risk in patients with high Lp(a) levels also was observed in a study published in 2010, where Dr. Hazen and other Cleveland Clinic investigators reported on the results of more than 2,700 patients followed over time. When the LDL (“bad”) cholesterol level was treated aggressively, an increase in cardiovascular risk associated with elevated Lp(a) levels was not observed.
The results “support the need to intensify lipid management in patients with elevated Lp(a) levels,” Dr. Hazen says.
What does it all mean?
The jury’s still out on who should be tested for Lp(a) cholesterol, and how it should be managed. The discovery doesn’t support widespread screening for Lp(a), but it raises a critical red flag.
According to a study published in the Journal of the American College of Cardiology, learning which patients have extremely high Lp(a) can help predict risk for heart attack in some individuals. European guidelines suggest treating patients with Lp(a) levels in the top 20 percent with niacin, though Cleveland Clinic’s Steven Nissen, MD, Chairman of the Robert and Suzanne Tomsich Department of Cardiovascular Medicine, says there is no outcome data suggesting that niacin will work to lower cardiac risks associated with Lp(a).
Dr. Hazen’s advice
The best prevention always includes the old-fashioned approaches: There’s no substitute for a healthy diet and exercise. But with this new information, patients with a strong family history of premature cardiac disease who show elevated Lp(a) could be candidates for aggressive LDL therapy, Dr. Hazen says.
“We don’t chase after lowering Lp(a) itself since, frankly, we have virtually no tools in our belt to do so,” Dr. Hazen says. “Rather, when Lp(a) is elevated, we become more aggressive at LDL lowering, with intensification of statin therapy.”