Gender Disparities Persist with CAD

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Coronary artery disease (CAD) is the leading cause of death in women in the U.S., according to the Centers for Disease Control and Prevention. It takes the life of more than 300,000 women annually, nearly 10 times that of breast cancer. Yet, imaging—often the bedrock for first diagnosis and then treating cardiac disease in women—remains inconsistent from the treatment of their male counterparts. Understanding gender differences in the physiology, symptoms and risk factors may help to reduce the gender gap and improve care.

The conundrum

Previously thought of as a "man's disease," there's been more acknowledgment in recent years of the serious risks of heart disease in women. CAD is more prevalent in men—8.3 percent of adult men live with the condition compared with 6.1 percent of adult women, according to the American Heart Association (AHA) 2011 Statistical Update. But women are more likely to die from a first MI and also experience more long-term disability.

Certain populations of women are at a higher risk. Risk increases for obese women and doubles for post-menopausal women. Estimated 10-year CAD risk is twice as high in diabetic women as non-diabetic women, and more than three times as high in diabetic women who smoke, according to the AHA. Also, women are less likely to undergo PCI and CABG than men.

Differences in treatment may be due to gaps in knowledge about symptom presentation and risk factors, with some physicians unaware of gender-specific care. Physicians often rely on long-standing beliefs that have proven to be effective ways of practicing medicine, says Leslee J. Shaw, PhD, co-director of the Emory Clinical Cardiovascular Research Institute at Emory University School of Medicine in Atlanta. "When you have populations that are changing and the risk is different from what you would have perceived in another era, that's tough for medical practice to keep up with," she adds.

Shaw says another issue could be the differences in symptom presentation such as shortness of breath, angina that is stress-triggered as opposed to exertion-related and atypical symptoms such as indigestion, nausea and discomfort in the elbow or jaw. "We don't have a female-specific description of anginal symptoms," Shaw says. "Many of the women who present with angina symptoms are classified as more atypical because they are not exertionally related … and don't present with those typical heart attack stories, such as shoveling snow or mowing the lawn."

Underused and unnecessary?

Over the last few decades, the use of myocardial perfusion imaging (MPI) to diagnose CAD has increased threefold, with a rate of utilization among Medicare beneficiaries of 8,467 per 100,000 in 2008 (AJR 2011;196:862-867). After examining these data on nuclear imaging exams, researchers have come across a new disparity: a higher percentage of women receive tests that don't meet appropriate use criteria. Aarti Gupta, MD, a cardiology fellow at Miriam Hospital in Providence, R.I., and colleagues conducted a study of 314 consecutive MPIs and found women accounted for 68 percent of the inappropriate tests and 82 percent of the uncertain tests.

This presents a fine line for physicians. On the one hand, women are under-tested, but on the other, a higher percentage of unnecessary tests occur in women referred for MPI.

"It's not always clear," says Gupta. "Our study shows that we are testing more women with nuclear stress tests than perhaps need the test, but, at the same time, we don't want to miss women with heart attacks as again, women can present with atypical symptoms."

Another finding of Gupta et al was that cardiologists were more likely than primary care physicians to order tests classified as appropriate at rates of 86 percent to 71 percent, respectively. She says uniformly applying the guidelines of the American College of Cardiology for appropriate use of nuclear stress testing would help, because