Heart Valve Disease Tied to Genetic Variants

Genetic variants that promote raised low density lipoprotein cholesterol levels tied to aortic valve calcium buildup and stenosis

(RxWiki News) LDL cholesterol is called "bad" cholesterol because it may contribute to heart and blood vessel disease. New research has shown that some people with genetic variations that cause raised levels of LDL cholesterol may be at increased risk for a type of heart valve disease.

Some people have genetic variations that cause increased levels of low-density lipoprotein cholesterol (LDL-C) in their blood.

A recent study found that people with these variations had an increased risk for calcium buildup in their heart valves and narrowing of their aortic valve, called aortic stenosis.

"While this study specifically looked at genetically high cholesterol, it is likely that elevation in cholesterol due to lifestyle and dietary choices would have a similar harmful effect on the aortic valve," said Sarah Samaan, MD, cardiologist and physician partner at the Baylor Heart Hospital in Plano, Texas.

"Aortic stenosis is more common in people in their 70s and older, but valve thickening and calcification develops earlier and progresses slowly over time," said Dr. Samaan, who was not involved in this study.

"Left untreated, aortic stenosis can cause heart failure and heart rhythm disorders, and severely impact quality of life," Dr. Samaan said. "The only treatment is surgery, which makes it even more important that we do everything we can to prevent the problem. Although this study does not address the question of  whether lowering cholesterol will prevent aortic stenosis, there is good reason to suspect that in fact it might.

This study was led by George Thanassoulis, MD, of McGill University Health Center in Montreal, Canada, and J. Gustav Smith, MD, of Lund University in Sweden.

"Our work provides confirmation that cholesterol is an important factor in the early stages of aortic valve disease and suggests that lowering cholesterol early in the disease process may provide protection from the development of aortic valve disease," Dr. Smith said in a press release.

The researchers used data from past studies on two large groups of patients — one group of 6,942 and another of 28,461. Researchers had taken images of these patients' blood vessels to look for calcium deposits and narrowing of the aortic valve. The aorta is the main artery in the heart.

The patients' blood cholesterol levels were also measured. Researchers analyzed the patients' genetic information and noted any mutations associated with genes tied to cholesterol.

In a study published in 2012 in JACC Cardiovascular Imaging, David S. Owens, MD, of the University of Washington in Seattle, and colleagues reported that aortic valve calcium increased the risk of heart and blood vessel problems like heart attack and stroke.

Dr. Thanassoulis and colleagues found calcium in the aortic valves of 32 percent of the group of 6,942 patients. Aortic stenosis — narrowing of the aortic valve — was found in 1.7 percent of the group of 28,461 patients over about 16 years.

Patients with higher levels of LDL-C were more likely to have aortic stenosis, Dr. Thanassoulis and team found.

People with genetic mutations tied to increased LDL-C had higher aortic valve calcium levels (38 percent higher) and a higher risk for aortic stenosis (three to four times higher) than people without the mutations.

According to authors of the current study, aortic valve disease cannot be slowed or stopped with current medical treatments. They said their study indicated that LDL-C may play a role in aortic valve disease and could be used as a target for treatment of valve disease.

"Whether earlier intervention to reduce LDL-C could prevent aortic valve disease merits further investigation," the authors noted.

The authors noted that their study only included data from people of European heritage.

This study was published online Oct. 26 in JAMA.

Several foundations in Sweden and grants from the National Institutes of Health and the National Heart, Lung, and Blood Institute funded the study. The authors disclosed no conflicts of interest.

Review Date: 
October 27, 2014