Just months earlier an angiogram had failed to detect signs of coronary artery disease. How could this be?
Research is finding that women and men are different, right down to the cellular level. And when it comes to cardiovascular disease, those differences are proving more fatal to women. But Women's Heart Health at Stanford, a new clinic that opened last year, is working to change those numbers. The clinic offers advanced cardiovascular clinical care and is conducting research on sex differences in heart and vessel disease.
Women do not need a doctor's referral to come to the clinic, which assesses a woman's risk for heart disease, does diagnostic evaluations, risk management and treatment of cardiovascular disease. The clinic also has a referral network that includes a dietician, a cardiothoracic surgeon, a psychiatrist, vascular surgeon, endocrinologist and gynecologist who provide sex-specific care. Women's Heart Health offers online risk assessment, a newsletter with access to the latest research and lectures by top cardiologists on gender-specific heart disease.
Women's cardiovascular disease is called "the silent epidemic," Dr. Hannah Valantine, senior associate dean of Stanford School of Medicine and clinic co-director, told a packed room at Stanford's Arrillaga Center on Feb. 7. An estimated 32 million American women per year — one in five — have cardiovascular disease.
Women have traditionally been treated based on research that has been done on men, according to Valantine. While death rates from heart attacks and strokes have steadily gone down for men, the numbers haven't dropped significantly for women, she said. "Cardiovascular disease is the leading cause of death, with 500,000 deaths annually. Fifty percent of those deaths are from coronary artery disease," she said.
Deaths for men decreased dramatically in the last 20 years, but women's deaths increased and have only begun to come down recently with the advent of gender-specific care, according to Valantine.
The reasons for the discrepancy are myriad. Obesity spiked in the United States in the 1990s, especially among women, and obesity and diabetes rose in African-American women and Latinas. Sex differences occur throughout cardiovascular disease and its diagnosis and treatment, Valantine said.
Women have delayed referrals when they complain of chest pain, are treated less aggressively and receive less diagnostic testing than men, she said.
Part of the problem is that diagnostic testing doesn't always show the damage inside the body. Clinical Director Dr. Jennifer Tremmel, an interventional cardiologist and researcher, has found that women with normal angiograms can have microvascular disease that consists of blocked smaller arteries and veins not picked up through conventional testing. And women also can have vascular functional abnormalities, such as endothelial dysfunction, when cells in arteries constrict when they are supposed to dilate, she said. It is not known if these same abnormalities affect men, she added.
Valantine said 50 percent of women who have coronary-artery disease show minimal or no blockage in angiograms compared to only 17 percent of men.
And younger women fare the worst, with those under 50 having a mortality rate double that for men in the same age group. Women with diabetes, hyperlipidemia (low HDL, high triglycerides and abdominal body fat), or those who smoke also fare worse than their male counterparts, she said.
Diabetes markedly increases the risk of heart disease in women over men. The risk factor is five to seven times greater in women compared with an increase of two to three times in men, Valantine said. And researchers have found that risks for women with pre-diabetes is almost as bad as for those with full-blown diabetes — but not so in men.
The classic symptom of a heart attack — major crushing pain in the chest — is not the same for women, Valantine said. Women frequently experience pain in the jaw or shoulder (58 percent), sweating (38 percent), nausea (29 percent), shortness of breath (29 percent), indigestion (21 percent) and weakness and fatigue (8 percent).
But there is some good news. Although women have increased mortality from stent implantation to open clogged arteries, new technologies that put medications on stents that keep plaque from reforming are helping to lower the risks.
Cardiologists are beginning to explore the role of depression and inflammatory response in cardiovascular disease, Valantine said.
The best way to prevent a heart attack is through measures such as managing diet, exercise and lifestyle changes, and to start early in life, Valantine said. The clinic offers an online Cardiovascular Sex Differences Monthly Journal Club, an electronic newsletter of research on sex differences in cardiovascular disease. And women can take an online risk assessment through the program or click on the link "Ten questions a woman should ask her healthcare provider" to access the American Heart Association's heart-attack risk assessment.
Women must be proactive in addressing heart disease, Valantine said. To run-of-the-mill treadmill tests, Valantine said just "say no." Women should push their doctors to do treadmill tests that are enhanced by imaging techniques, she added.
But if symptoms of a heart attack come, women should not waste time getting emergency help, according to Valantine. Studies show that as many as 90 percent of women delayed going to the hospital when they had symptoms of heart attack, increasing their risk of death. Self-doubt, embarrassment and denial were among reasons for the delay.