Mammography May Detect Heart Disease
Study Shows Calcium in Breast Arteries Increases Risk for Heart Attacks
Dec. 4, 2002 (Chicago) -- Heart disease kills more than 365,000 women each year, which is makes it eight times more deadly than breast cancer, yet women pay more attention to breast cancer screening with mammography than they do to regular checks of cholesterol and blood pressure. But new research suggests that mammograms may also help in determining a woman's risk for heart disease, thus greatly increasing the lifesaving potential of mammograms.
Kirk Doerger, MD, a radiology resident at the Mayo Clinic in Rochester, Minn., tells WebMD that he became intrigued by the possible mammogram-heart disease link after "one of my patients came in with a magazine article that said calcium in breast arteries was a better predictor of heart disease risk than either blood pressure or cholesterol levels."
Doerger says the woman was not quite right: Calcium in breast arteries is associated with a 20% increase in risk for heart disease, while high blood pressure, diabetes, and high cholesterol carry higher risks. But "a 20% increase in risk can be important for a 40-year-old woman with no symptoms," says Doerger.
He identified the risk by analyzing data from more than 1,800 women who had both mammograms and angiograms, which are X-ray studies of arteries in the heart.
Doerger worked out a formula to determine a breast artery calcium index or BAC. There are three major arteries in each breast, so he totals the number of calcified arteries and divides that number by two to account for both breasts. Thus the highest possible "BAC" index is 3.0, he said.
He then determined how the BAC related to heart disease, which he defined as a blockage of at least 50% in at least one artery in the heart. He said that breast artery calcification becomes "a significant risk factor when the BAC score is 1.5 or higher, but risk doesn't increase with higher scores." Moreover, he said that scores of 1.5 or higher were most common among older women "who are already at increased risk for cardiovascular disease."
That increase is significant enough for the Mayo Clinic to now require radiologists to include information about breast artery calcium in their mammography reports, he said. "We just think this is part of good patient care."
Moreover, checking the mammograms for breast artery calcification has almost no downside: It doesn't require more tests, has no additional charge for women, and doesn't require any more time from women. In fact, calcified breast arteries are so obvious on a mammogram that even an untrained observer can spot them, says Doerger. "It is actually easier to identify arterial calcification than it is to identify small tumors," he says.
Hedvig Hricak, MD, PhD, chairwoman of the department of radiology at Memorial Sloan-Kettering Cancer Center in New York, says, however, that the calcifications are most common in older women and Doerger's study shows that there is a clear association with age. So she says that calcifications in a "70-year-old are probably not that clinically relevant."
"But if these calcifications occur in a 40-year-old then it would be something that her primary care physician should know about because it could indicate early heart disease," Hricak says. Women are more careful about showing up for annual mammograms then they are "about getting regular checkups with their internists, so they could have other risk factors that are undetected, in which case this would be more important."