Men and women have different risk profiles when it comes to coronary artery disease. Women often develop symptoms later than men. They are more likely to have high blood pressure and dyslipidemia, a condition characterized by abnormal levels of lipids, or fats, in the blood stream.
Women are also more likely to be diagnosed with non-obstructive coronary artery disease, a condition that leads to a higher number of adverse events than obstructive disease.
Women tend to have less arterial plaque. That may sound like a good thing, but unfortunately, a recent study shows that it is not. Even with less plaque, a woman's risk of a heart attack or other cardiovascular event due to plaque deposits is higher than that of a man, an international team led by researchers at Harvard University and Massachusetts General Hospital found.
Researchers measured the plaque in the arteries of more than 4,200 men and women who had an average age of 60 years old and had enrolled in the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE).Women have smaller coronary arteries, so a smaller amount of plaque can have a bigger effect on cardiac risk.
The team used a procedure that significantly improves risk prediction for coronary events — coronary computed tomography angiography, an X-ray of the heart and blood vessels that measures total plaque volume relative to total blood vessel volume.
People in the study were followed for about two years. The researchers found that fewer women had arterial plaque: 55 percent of women had plaque compared to 75 percent of men. They also had roughly half the volume of plaque compared to men.
Despite having less plaque, however, women were just as likely as men to be hospitalized for chest pain, have a non-fatal heart attack or die from any cause because their risk of heart attack started at lower levels of plaque than men.Women's heart attack risk rose more sharply than men's as plaque levels increased, particularly after they went through menopause.
Women's serious heart risk began to increase at a plaque burden of 20 percent; men's risk began to increase at 28 percent. Their heart attack risk as plaque levels increased also rose more sharply than men's, particularly after they went through menopause.
“Women are not ‘protected' from coronary events despite having lower plaque volumes,” Borek Foldyna, senior author on the study and an assistant professor of radiology at Harvard Medical School, said in a statement. Women have smaller coronary arteries, he explained, so a smaller amount of plaque can have a bigger effect on their risk of a heart attack or stroke.
Standard definitions of high cardiac risk, based as they have been on men, are therefore likely to underestimate the risk in women.
The researchers were surprised at how subtle these differences were. “Rather than reveal a dramatic biological divide, the study findings showed that the relationship between plaque and cardiovascular risk may differ in degree rather than in kind,” Jan Brendel, first author on the study and a postdoctoral fellow at Harvard Medical School and Massachusetts General Hospital, told TheDoctor in an email.
Going forward, the researchers are interested in looking at age-specific and gender-specific plaque burden in relation to coronary risk. “Ultimately, the goal is to move toward more individualized cardiovascular risk assessment, where imaging tests are interpreted in context, not uniformly across populations,” said Brendel.
The study and a related editorial are published in Circulation: Cardiovascular Imaging.
