A Wake-up Call
Section titled “A Wake-up Call”This month I want to tell you some things you may not know about women and heart disease. Too often I find women in my practice focusing their health concerns on breast cancer. They religiously perform their monthly breast exams but completely ignore the possibility of a heart attack. That’s unfortunate, because heart disease is the biggest killer of women. While women fail to take preventive measures, the medical profession does too.
Most heart disease research has been done by men, on men, for men. Because we still rely on risk assessments based on male physiology, women’s heart disease goes unsuspected and undetected. More women arrive at their first heart attack with no warning. There are real gender differences in symptoms and outcomes, and failure to understand these issues can be fatal.
Young Women at a Disadvantage
Women under the age of 50 are twice as likely to die during hospitalization for a heart attack as are men1. We’re not sure why. Lack of awareness of their condition and lack of medical management may explain part of it. More research needs to be done to help us understand why relatively young women suffer more severe and deadly heart attacks than do their male counterparts. We do know that the difference in mortality rates evens out with age, becoming identical after the age of 742.
Further, if a woman survives her heart attack, she is more likely than her male counterpart to die in the following year. She is twice as likely to have suffered a second heart attack within six years.
Diagnosing Women’s Heart Disease
We diagnose incipient heart disease by performing an angiogram to look at a person’s arteries and see if they are lined with plaque. Whereas a simple-minded male artery will show irregularity and narrowing, the more subtle “put your best foot forward” female artery maintains a smooth interior contour. The plaque in her arteries expands outward in such a way that it doesn’t show up on of the X-ray image. The major arteries in a female may appear normal on an angiogram when they actually suffer from problems in the endothelial lining.
The Important Endothelium
The endothelium lines all our blood vessels, and prevents our blood from clotting. If we are injured, blood has to be ready to clot at any moment or else we bleed to death. However, we don’t want it to clot in the blood vessels. The Teflon-like lining, the endothelium, is too slick for blood cells to stick to and therefore prevents clotting in the normal situation. However, should that endothelial lining be damaged, the blood will clot, which could cause a stroke or a heart attack. While women tend to develop heart disease much later in life than men, on average, when they do develop it they are more likely to have endothelial damage. In addition, their smaller arteries are more likely to be diseased than a man’s are. Such microscopic disease does not lend itself to surgical repair. You can find more information about the endothelium in our June 2006 newsletter and at Wikipedia.
What’s Happening to that Woman?
Emergency diagnosis during a heart attack is also a problem. Whereas every medical student learns that a heavy feeling in the mid-chest, perhaps with pain in the jaw or arm, may signal a heart attack in men, women often do not give us such easy clues. The symptoms of impending heart attack are much more subtle in women. They include fatigue, disturbed sleep, and occasionally, shortness of breath. Only 10 percent have chest pain ahead of the attack, rising to half with chest pain during the attack. Moreover, the pain may not be the typical mid-chest pressure; it can occur anywhere in the torso or back.
Know Your Risk
Over fifty years ago, investigators enlisted the good people of Framingham, Massachusetts in a long-term health study, measuring cholesterol, blood pressure, and many other physiologic variables, then watched to see who got sick with what, or died from what. Using the information they recorded, they developed risk assessment tools, such as the Medical College of Wisconsin’s Coronary Heart Disease Risk Calculator. As it turns out, this popular predictive tool can falsely reassure us that a woman is not at risk, when she is. That’s because there are shortcomings in the risk models. Elevated triglyceride levels are more dangerous in women than in men. A better predictor for women is the Reynolds Risk Score.
Smoking, diabetes and C-reactive protein levels are also stronger risk indicators in women than in men. The C-reactive protein test measures the general level of inflammation in the body, by testing for a specific indicator protein in the blood. This test is not as well known or widely used as a cholesterol panel, but studies show that inflammation level has proven to be a better indicator of heart attack risk than cholesterol. This is a simple blood test with no fasting or special preparation needed. For more information, see our November 2002 newsletter.
The coronary artery calcium score is much more predictive of heart disease in women than in men, as is the stress echocardiogram. The coronary artery calcium score tells us how much calcium is in the blood vessels of your heart. For this test, you lie supine in a CT scanner and hold your breath for ten seconds. The scanner synchronizes itself with your heartbeat, making an image only when the heart is resting between beats. If there is calcium in your coronary arteries, it shows up on the image of the heart, telling the radiologist which arteries are involved and how severely. While special MRI scans can pick up plaque before calcium is present, such scans are technically challenging and cost upwards of $2000. The coronary artery calcium test costs $99.
Preventing Heart Attacks
Some medications are touted to help prevent heart disease. While estrogen replacement therapy makes a woman’s blood tests look better, it elevates the actual incidence of heart attacks. Aspirin is helpful to reduce stroke but does not reduce heart attack as it does in men. Statins stabilize the endothelium, so they do much more towards preventing a heart attack than merely lowering cholesterol.
Your best strategy for preventing a heart attack does not come in a pill. These lifestyle choices reduce your risk of heart disease3.
- Keep your weight in check. Women who have a body-mass index under 25 have fewer strokes and heart attacks.
- Don’t smoke. This is a no-brainer.
- Drink a bit of wine with dinner. Half a glass of alcohol lends protection.
- Exercise. An active life is a healthy life. Those who engage in moderate to vigorous physical activity such as a brisk walk or a bike ride at least half an hour a day grow a healthier heart.
- Eat foods that are high in fiber and low in saturated fat and low on the glycemic index. Fish oil and folic acid also protect the heart.
Be Your Own Advocate
Remember that you as a woman are not immune to a heart attack. If you are over 50 and your doctor doesn’t mention cardiac health, bring it up yourself. Get your C-reactive protein levels checked along with your triglycerides. Consider a coronary artery calcium score.
Be alert. If you have some “funny symptoms in your chest,” or if you have unusual fatigue and shortness of breath, see your physician right away.
For more on the heart, see our June, 2008 newsletter article, "The Heart Detective at Work".
Footnotes
1: ABSTRACT Background There is conflicting information about whether short-term mortality after myocardial infarction is higher among women than among men after adjustment for age and other prognostic factors. We hypothesized that younger, but not older, women have higher mortality rates during hospitalization than their male peers. Methods we analyzed data on 384,878 patients (155,565 women and 229,313 men) who were 30 to 89 years of age and who had been enrolled in the National Registry of Myocardial Infarction 2 between June 1994 and January 1998. Patients who had been transferred from or to other hospitals were excluded. Results the overall mortality rate during hospitalization was 16.7 percent among the women and 11.5 percent among the men. Sex-based differences in the rates varied according to age. Among patients less than 50 years of age, the mortality rate for the women was more than twice that for the men. The difference in the rates decreased with increasing age and was no longer significant after the age of 74 (P< 0.001 for the interaction between sex and age). Logistic-regression analysis showed that the odds of death were 11.1 percent greater for women than for men with every five-year decrease in age (95 percent confidence interval, 10.1 to 12.1 percent). Differences in medical history, the clinical severity of the infarction, and early management accounted for only about one third of the difference in the risk. After adjustment for these factors, women still had a higher risk of death for every five years of decreasing age (increase in the odds of death, 7.0 percent; 95 percent confidence interval, 5.9 to 8.1 percent). Conclusions After myocardial infarction, younger women, but not older women, have higher rates of death during hospitalization than men of the same age. The younger the age of the patients, the higher the risk of death among women relative to men. Younger women with myocardial infarction represent a high-risk group deserving of special study. (N Engl J Med 1999;341:217-25.)
2: N Engl J Med 341:275, July 22, 1999 Editorial
3: N Engl J Med 2000;343:16-22