University of Virginia Health System

Heredity and Coronary Fatty Deposits Linked

Heredity sometimes influences where fatty deposits develop in a coronary artery, researchers report in Circulation: Journal of the American Heart Association.

“Different locations of disease show different degrees of inheritance,” says Dr. Ulrich Broeckel, a study author. “The most hazardous ones have a high heritability.”

The new findings, if confirmed, could affect heart disease screening strategies for close relatives of coronary heart patients.

Taking Genetic Knowledge a Step Further

Coronary heart disease involves a complex combination of genetic and environmental factors. Physicians have long known that a family history of the disease is a major risk factor for a heart attack.

But, researchers have devoted scant attention to whether genes might partially govern where the fatty deposits develop within the heart’s arteries.

“As far as we can determine, we are the first to do a large study of the genetic contribution to the location and pattern of coronary lesions,” comments Dr. Broeckel, assistant professor of medicine at the Medical College of Wisconsin in Milwaukee.

He and his colleagues conducted their study as part of a 10-year collaboration that includes the Medical College of Wisconsin, the University of Regensburg in Germany, and the University of Luebeck, also in Germany.

The researchers studied angiograms of 882 siblings with coronary artery disease from 401 families. One person from each family had had a heart attack before age 60 and at least one sibling had had a heart attack or coronary revascularization (angioplasty, stenting, or coronary artery bypass surgery).

The team compared the angiograms of the 401 persons who experienced a heart attack before age 60 (one from each family) to that of a sibling who had had a heart attack or revascularization procedure.

They found that a large number of sibling groups had shared disease patterns, indicating a genetic influence.

After considering several factors that affect the risk of coronary disease, such as age, gender, hypertension, and diabetes, an analysis showed a statistically significant association between inheritance and:

• coronary heart disease at the point where the coronary arteries branch off from the aortic artery, as well as in the upper parts of the left and right coronary arteries. A blockage there shuts off blood flow to a greater proportion of the heart than one lower down.
• the degree of artery ectasia - abnormally widened portions of the vessels, which are associated with coronary heart disease.
• the amount of calcified artery deposits.

The researchers found a lesser degree of statistically significant influence, or none at all, between heredity and:

• coronary disease in the lower parts of the heart’s left and right arteries.
• diffuse disease - heart disease spread throughout at least two-thirds of an artery. When the right and left coronary arteries were compared separately, there was a higher heritability in the left artery.
• the pattern of blood supply, as determined by whether the right or left artery dominated the flow of blood.
• whether a person had disease in one, two, or three arteries.

More Study Needed To Help Identify Risks

The researchers did not design the study to reveal the actual genes that might influence disease development at different artery sites. “That is our next step,” Dr. Broeckel notes.

The study findings may help improve screening for relatives of people with coronary heart disease, he says. For example, the genetic link to disease in the left main artery may offer a more precise way to predict a relative’s risk of having or developing the same problem.

The researchers note several limitations of the study that could affect its results. All the participants were Caucasian and of northern European origin, which means the genetic findings might not apply to other ethic groups.

Moreover, the study did not consider to what degree the siblings shared the same living environment, which could mean an overestimation of the genetic role in disease at specific sites.

Always consult your physician for more information.