Coronary Microvascular Syndrome (CMS):
The Hidden Heart Attack Risk They STILL Aren't Checking For
© 2017 Health Realizations, Inc. Update
As many as 3 million U.S. women may be unknowingly at risk of heart disease because they suffer from coronary microvascular syndrome (CMS), according to the National Heart, Lung, and Blood Institute's (NHLBI) Women's Ischemia Syndrome Evaluation (WISE) study.
Women who have chest pain yet an angiogram comes out clear may still be at high risk of a heart attack if they have coronary microvascular syndrome.
Women with CMS may have shortness of breath or chest pain, but, upon visiting their doctor, be told nothing is wrong and sent home. That's because CMS is not detected by an angiogram, which is widely accepted as the best test for diagnosing heart disease.
Unlike typical heart disease cases, in which accumulated plaque in the large arteries shows up as bulky clogs, in CMS plaque "evenly coats" the very small arteries of the heart. The arteries are too small to appear on the angiogram, much like "seeing a pine tree's branches but not its needles," said Dr. George Sopko, a heart specialist at the National Institutes of Health.
When these small arteries become narrowed, less oxygen is able to flow to the heart, resulting in chest pain and a high risk of heart attack. Further, coronary microvascular syndrome also appears to affect the lining of the inner wall of the artery, making the blood vessels not dilate correctly, according to Dr. C. Noel Bairey Merz of Cedars-Sinai Medical in Los Angeles, who led the WISE study.
According to WISE findings, about two-thirds of women with chest pain receive a "clear" angiogram, yet half of them actually have CMS.
CMS Mostly Affects Women
About 80 percent of patients with coronary microvascular syndrome are women. "It appears to be primarily a woman's problem, which is probably why we've missed it all these years (that) we didn't bother to study women," said Bairey Merz.
Heart disease, which is responsible for 480,000 deaths a year, kills more women than men, and researchers are just beginning to scratch the surface on how gender affects this disease.
The WISE study, which began in 1996 and is ongoing, is one such study aimed to help clear up this issue. It follows about 1,000 women with the goal of improving diagnosis and understanding of heart disease in women. The women in the study had experienced chest pain or other heart disease symptoms, yet showed no evidence of clogged arteries after receiving an angiogram.
The WISE study found that about 15 percent of all coronary artery disease in women is coronary microvascular syndrome. Other findings, according to Carl Pepine, chief of cardiovascular medicine at the University of Florida and a WISE researcher, include:
Only one-third of participants had obvious artery blockages. Comparatively, in a similar group of men three-quarters would have obvious blockages.
Of those without obvious blockages, over 50 percent had abnormalities that could cause ischemic heart disease.
The rate of death or heart attack after four years among those without obvious blockages was 10 percent, which Pepine said was "much too high for somebody with a normal coronary angiogram."
Women, Ask Your Doctor About CMS
"This study and the high prevalence of coronary microvascular dysfunction demonstrate that we must think out of the box when it comes to the evaluation and diagnosis of heart disease in women," said NHLBI Director Elizabeth G. Nabel, M.D.
If you've had chest pain or shortness of breath, and a clear angiogram, ask your doctor to rule out CMS.
If you are a woman and have experienced chest pain, shortness of breath, fatigue or other symptoms of heart attack or heart disease, yet an angiogram comes out clear, you should be prepared to ask your doctor about CMS.
"It is no longer adequate to simply demonstrate open arteries," Bairey Merz explained.
"The No. 1 message for women is, 'Pay attention to your symptoms,"' said Sopko. "If you don't have visible blockages, that doesn't mean you're not at risk."
However, many physicians may simply give you a clean bill of health and send you home. "There are women who have chest pain and we do all this testing and there's nothing wrong -- and that's good," Bairey Merz said. "[But] we need to stop falsely reassuring women unless we're willing to do this additional work."
The additional work he's referring to includes more complicated tests than an angiogram. One way to detect coronary microvascular syndrome is to measure whether a person's arteries dilate properly when injected with certain medications. Another is to perform an MRI scan of the heart.
The researchers also recommended the following guidelines for women who have chest pain, yet an angiogram does not show any blockages:
Take a "functional capacity test." This is a questionnaire, which cardiologists are well aware of, that measures your difficulty level in performing everyday activities. Those who pass an angiogram, yet get a low score on this test, have an increased risk of heart attack, according to WISE researchers.
Your doctor should avoid treadmill tests, as these do not detect 40 percent of women with ischemic heart disease.
If you are a premenopausal woman with high blood pressure, or an overweight woman of any age, you should be considered at high risk of heart problems.
CBS News: Heart Disease Undetected in Many Women
What Is Coronary Microvascular Disease? - NHLBI, NIH
Second Opinion - Coronary Microvascular Disease