Study finds Women at Greater Risk from Serious Angina than Men
Posted by on September 10, 2010 - 11:25am

Women with the most serious type of angina are three times as likely as men with the same condition to develop severe coronary artery disease (CAD), researchers have found.

In the study, Canadian researchers analyzed the medical records of 23,771 patients referred for a first diagnostic angiography. They found that women over age 60 with the most serious type of angina (Class IV) had a 21 percent higher absolute risk of developing CAD than did men. Women younger than 60 had an 11 percent greater risk of CAD than men in the same age group.

When the researchers factored in other variables commonly associated with CAD -- such as diabetes, high blood pressure, high cholesterol, smoking and age -- they found that Class IV angina increased the risk of CAD by 82 percent in women and 28 percent in men.

The study also found that men were more likely to have severe CAD than women (37 percent versus 22 percent) and that women with severe CAD tended to be significantly older than men with severe CAD (70 years versus 66 years).

The study findings are published in the July issue of the Journal of Internal Medicine.

"CAD is the leading cause of ill health and death in men and women in the western world, accounting for over a third of deaths. In fact, more women die from CAD than breast disease every year. Despite this, there is still a persistent perception that CAD is a man's disease," lead author Catherine Kreatsoulas, of the department of clinical epidemiology and biostatistics at McMaster University in Hamilton, Ontario, said in a news release from the journal's publisher.

However, the university's research found that women who have what the Canadian Cardiovascular Society defines as Class IV angina -- which means they are unable to perform any activity without symptoms and even suffer angina at rest -- "are significantly more likely to develop severe CAD than men with the same condition," Kreatsoulas added.

The findings are crucial for doctors deciding which patients should be referred for coronary angiography, Kreatsoulas said.

SOURCE: Journal of Internal Medicine, news release, July 8, 2010.

Copyright (c) 2010 HealthDay. All rights reserved.

Chocolate May Lower Risk of Heart Failure
Posted by on August 20, 2010 - 10:04am

Benefits shown in middle-aged and elderly women

Middle-aged and elderly Swedish women who regularly ate a small amount of chocolate had lower risks of heart failure risks, in a study reported in Circulation: Heart Failure, a journal of the American Heart Association.  The nine-year study, conducted among 31,823 middle-aged and elderly Swedish women, looked at the relationship of the amount of high-quality chocolate the women ate, compared to their risk for heart failure. The quality of chocolate consumed by the women had a higher density cocoa content somewhat like dark chocolate by American standards. In this study, researchers found:

  • Women who ate an average of one to two servings of the high-quality chocolate per week had a 32 percent lower risk of developing heart failure.
  • Those who had one to three servings per month had a 26 percent lower risk.
  • Those who consumed at least one serving daily or more didn’t appear to benefit from a protective effect against heart failure.

The lack of a protective effect among women eating chocolate every day is probably due to the additional calories gained from eating chocolate instead of more nutritious foods, said Murrray Mittleman, M.D., Dr.P.H., lead researcher of the study.  “You can’t ignore that chocolate is a relatively calorie-dense food and large amounts of habitual consumption is going to raise your risks for weight gain,” said Mittleman, director of the Cardiovascular Epidemiology Research Unit at Harvard Medical School’s Beth Israel Deaconess Medical Center in Boston. “But if you’re going to have a treat, dark chocolate is probably a good choice, as long as it’s in moderation.”

High concentration of compounds called “flavonoids” in chocolate may lower blood pressure, among other benefits, according to mostly short-term studies. However, this is the first study to show long-term outcomes related specifically to heart failure, which can result from ongoing untreated high blood pressure.   In the observational study, researchers analyzed self-reported food-frequency questionnaire responses from participants 48-to-83-years-old in the Swedish Mammography Cohort. Combining the results with data from national Swedish hospitalization and death registries between 1998 through 2006, the researchers used multiple forms of statistical modeling to reach their conclusions on heart failure and chocolate consumption.

Mittleman said differences in chocolate quality affect the study’s implications for Americans. Higher cocoa content is associated with greater heart benefits. In Sweden, even milk chocolate has a higher cocoa concentration than dark chocolate sold in the United States.    Although 90 percent of all chocolate eaten across Sweden during the study period was milk chocolate, it contained about 30 percent cocoa solids. U.S. standards only require 15 percent cocoa solids to qualify as dark chocolate. So, by comparison, American chocolate may have fewer heart benefits and more calories and fat per equivalent amounts of cocoa content compared to the chocolate eaten by the Swedish women in the study.   Also, the average serving size for Swedish women in the study ranged from 19 grams among those 62 and older, to 30 grams among those 61 and younger. In contrast, the standard American portion size is 20 grams.

“Those tempted to use these data as their rationale for eating large amounts of chocolate or engaging in more frequent chocolate consumption are not interpreting this study appropriately,” said Linda Van Horn, Ph.D., R.D., immediate past chair of the American Heart Association Nutrition Committee and professor in the Department of Preventive Medicine at Northwestern University’s Feinberg School of Medicine in Chicago. “This is not an ‘eat all you want’ take-home message, rather it’s that eating a little dark chocolate can be healthful, as long as other adverse behaviors do not occur, such as weight gain or excessive intake of non-nutrient dense ‘empty’ calories.”

Heart failure occurs among about 1 percent of Americans over age 65. A condition in which the heart can’t pump enough blood to the rest of the body, heart failure rates are increasing as our aging population grows.“Anything that helps to decrease heart failure is an important issue worth examining,” Mittleman said.

Co-authors are Elizabeth Mostofsky, M.P.H.; Emily Levitan, Sc.D.; and Alicja Wolk, Dr.Med.Sci. Author disclosures and funding support are on the manuscript.

Source: Press release prepared by the American Heart Association

Hypertension in Women
Posted by on August 13, 2010 - 9:49am

Postmenopausal women have an increased risk of hypertension (high blood pressure), and among older adults, more women than men have hypertension.   As with many other health issues, hypertension research has been conducted predominately in males, and little is known about how women's bodies manage blood flow.   Research conducted by Heidi A. Kluess at the University of Arkansas is focusing on a  better understanding of hypertension in women by using a new technique to examine the release of a neurotransmitter in small blood vessels.

Kluess, an exercise scientist, believes the answer seems to be in the "synapse".  The synapse is the space between the nerve and the vascular smooth muscle, the place where the nerve and blood vessel interact.   A neurotransmitter crosses the "synapse" to activate a receptor, which then causes the artery to constrict.   "There's been a little evidence to say that some of the neurotransmitter breakdown is different in women.   It suggests that when we've been looking at receptors on the smooth muscle, we may have been missing a big part of the story, particularly in women," Kluess said.

The team measured the neurotransmitter adenosine triphosphate (ATP) coming from the small blood vessels (arterioles).  ATP plays a key role in controlling blood flow and blood pressure by causing the diameter of blood vessels to change.   Thus, the constriction of veins associated with hypertension could be related to relatively high levels of ATP in arterioles. So this raises the questions:   Where is the ATP coming from, what tissues are releasing it and how does this change with aging?

To study this,the researchers had to overcome the difficulty of working with very small blood vessels that produced minute amounts of ATP.   A biosensor that was only previously used in brain researcher was utilized that uses a set of enzymes to indirectly measure ATP as it is released.

The research findings suggest that ATP from small arterioles can be measured and that the arteriole wall plays an important role in release and management of ATP. The researchers found that ATP is released mostly from the sympathetic nerves in the arteriole wall and that only a small part comes from the smooth muscle. Considerable research suggests that having a lot of ATP floating around in the blood vessels is not a good thing. The upside of this finding is that the nerve releases ATP in response to nerve signals. However, the mechanisms involved in the release of ATP by smooth muscles are less well understood, Kluess explained, and may result in chronically high ATP release.

The researchers found that the ATP overflow varied considerably with age. Because ATP is associated with vascular growth, it is important during early development when blood vessels are growing, but levels generally decline when people reach their twenties. Elevated levels can be a bad sign during aging when the body is no longer growing and may be a predictor of vascular changes that can be detected years before hypertension is a problem.

Some previous research had suggested that the endothelium – the outer layer of the smooth muscle – produced ATP. However, Kluess’ research showed that the endothelial tissue did not produce ATP. Rather, it decreased levels of ATP and potentially plays a positive role in controlling ATP levels.

“That’s an interesting finding because we know that as people age or develop disease that their endothelium doesn’t work as well,” Kluess said. “That may be a way that ATP increases during aging because the endothelium doesn’t function as well and so can’t buffer ATP quite as well.”

More research is needed to investigate the factors that control ATP overflow and metabolism to reveal the mechanisms associated with age-related change. “We are very much at the beginning of this story,” Kluess said.

Source:   University of Arkansas

Kluess HA, Stone AJ, Evanson KW. ATP overflow in skeletal muscle 1A arterioles. J Physiol.

Cholesterol and the Menstrual Cycle
Posted by on August 10, 2010 - 3:36pm

Women's cholesterol levels vary with phase of menstrual cycle
NIH findings suggest a need to consider phase of cycle when measuring cholesterol

National Institutes of Health researchers have shown that women's cholesterol levels correspond with monthly changes in estrogen levels. This natural variation, they suggest, might indicate a need to take into account the phases of a woman's monthly cycle before evaluating her cholesterol measures. On average, the total cholesterol level of the women in the study varied 19 percent over the course of the menstrual cycle.

In a typical cycle, estrogen levels steadily increase as the egg cell matures, peaking just before ovulation. Previous studies have shown that taking formulations which contain estrogen — oral contraceptives or menopausal hormone therapy — can affect cholesterol levels. However, the results of studies examining the effects of naturally occurring hormone levels on cholesterol have not been conclusive. According to the NIH’s National Heart, Lung and Blood Institute, high blood cholesterol levels raise the risk for heart disease.

The researchers found that as the level of estrogen rises, high-density lipoprotein (HDL) cholesterol also rises, peaking at the time of ovulation. HDL cholesterol is believed to be protective against heart disease.

In contrast, total cholesterol and low-density lipoprotein (LDL) cholesterol levels — as well as another form of blood fat known as triglycerides — declined as estrogen levels rose. The decline was not immediate, beginning a couple of days after the estrogen peak at ovulation. Total cholesterol, LDL cholesterol and triglyceride levels reached their lowest just before menstruation began.

The findings were published online in The Journal of Clinical Endocrinology and Metabolism.  To read the full NIH Press Release click here.

Measuring Peak Heart Rate in Women
Posted by on July 1, 2010 - 10:35am

Women who measure their peak heart rates for exercise will need to do some new math, as will physicians giving stress tests to patients.  A new formula based on a large study from Northwestern Medicine provides a more accurate estimate of the peak heart rate a healthy woman should attain during exercise. It also will more accurately predict the risk of heart-related death during a stress test.

“Now we know for the first time what is normal for women, and it’s a lower peak heart rate than for men,” said Martha Gulati, MD, assistant professor of medicine and preventive medicine and a cardiologist at Northwestern Medicine. “Using the standard formula, we were more likely to tell women they had a worse prognosis than they actually did.”   Gulati is the lead author of a study published June 28 in the journal Circulation.

“Women are not small men,” Gulati added. “There is a gender difference in exercise capacity a woman can achieve. Different physiologic responses can occur. ”   Gulati was the first to define the normal exercise capacity or fitness level for women in a 2005 study.

The old formula -- 220 minus age -- used for almost four decades, is based on studies of men. The new formula for women, based on the new research, is 206 minus 88 percent of age.   At age 50, the original formula gives a peak rate of 170 beats per minute for men and women. The new women’s formula gives a maximum heart rate of 162 beats for women.  Many men and women use their peak heart rate multiplied by 65 to 85 percent to determine their upper heart rate when exercising.

“Before, many women couldn’t meet their target heart rate,” Gulati said. “Now, with the new formula, they are actually meeting their age-defined heart rate.”    The new formula is trickier to calculate, Gulati acknowledged, but is easily determined with a calculator. She currently is working on an iPhone application for a quick calculation.

The new formula is based on a study of 5,437 healthy women ages 35 and older who participated in the St. James Women Take Heart Project, which began in the Chicago area in 1992.    With the new formula, physicians will more accurately determine if women are having a normal or abnormal response to exercise.    “If it’s abnormal, that’s a marker for a higher risk of death,” Gulati said. “Maybe we need to talk about whether you exercise enough and what we need to do to get it into the normal range.

“We need to keep studying women to get data applicable to women,” Gulati said. “It’s important to not get complacent that we have data on men and assume women must be the same. They’re not.”

Gulati’s senior author on the study was the late Morton Arnsdorf, MD, professor emeritus and associate vice chairman of medicine and former section chief of cardiology at the University of Chicago.

Reducing Salt as a Public Health Intervention
Posted by on May 5, 2010 - 4:55pm

A recent article by Appel and Anderson in the New England Journal of Medicine, reaffirms previous studies that have suggested that salt intake reduction can be a highly effective, inexpensive way to reduce deaths due to heart disease and stroke.  Table salt is 40% sodium and 60% chloride and the maximum recommended levels of sodium is 2300 mg per day (about 1 teaspoon of salt).   The mean intake of salt (reported as sodium on food labels)  in the United States is very high and far above the recommended levels.   Unfortunately, American men average a consumption of between 3100-4700 mg. of sodium per day; women range 2300-3100 mg.

It is well known that sodium plays a role in developing high blood pressure (hypertension) and that high salt at an early age may enhance our propensity to high blood pressure in certain populations as we age. It is the sodium part of table salt that is significant.   In an earlier blog on sugar, we mentioned that sugar occurs naturally in certain foods. The same is true for sodium.   One of the ways we can lower salt intake is to simply cook with less salt and not salt the food once it gets put on our plates.  However, about 75% of our dietary salt comes from processed foods that contain the mineral before we even prepare it.   A good example is the tomato.    A fresh tomato naturally has 14 mg. of sodium; a cup of canned tomato soup has 932 mg. of sodium per cup (depending on manufacturer).   Another example:  3 ounces of fresh tuna has 50 mg. sodium and the same amount of canned tuna has 384 mg. sodium.   Part of the challenge is to convince policy makers and the public at large that prevention in the long run is much cheaper than the treatment of heart diseases and stroke.

According to the authors cited above, a national effort to reduce daily sodium intake by 1200 mg. could annually reduce the number of new cases of coronary heart disease by 60,000-120,000 and there also would be significant reductions in new cases of stroke and heart attack.    Sound like a simple fix?  This would involve major changes in the food industry, our lifestyles and our cooking patterns.   While people already impacted by these chronic health conditions may adapt, would people who are currently healthy be inclined to pass up a piece of grandma's apple pie for a fresh picked apple?

HRT and Heart Disease--An Update
Posted by on February 17, 2010 - 2:22pm

On February 15, 2010 the NIH issued a news release about a new analysis reported in the Annals of Internal Medicine on data from the Women's Health Initiative (WHI).  The study reevaluated whether or not combination hormone therapy (estrogen+progestin) increases the risk of heart disease in healthy postmenopausal women. Researchers from the National Heart, Lung, and Blood Institute (NHLBI) and the Harvard School of Public Health reanalyzed data from the WHI, comparing the effects of hormone therapy (HT) on heart disease risk among women who began hormone therapy within 10 years of menopause to women who began therapy more that 10 years after menopause. Recently, there has been a lot of debate among clinicians and researchers whether or not the time between the start of menopause and the initiation of hormone treatment affects the cardiovascular risk.  Some believed that the risk may not be present in women who start HT shortly after they go into menopause.  In this new study,  the researchers compared women who started combination hormone (estrogen+progestin) treatment within 10 years of menopause to women who began therapy more than 10 years after menopause and examined the impact on heart disease over time (up to eight years). The new study did not include women who took estrogen only.

The researchers reported a trend toward a possible increased risk of heart disease in the first two years among the women who started hormone therapy within 10 years after menopause and the increased risk persisted in this group an average of 6 years, after which those in the treatment group appeared to have a lower risk of heart disease compared to similar women who were not on combination hormone therapy.  In contrast, women who started hormone therapy 10 years or more after menopause were nearly 3 times more likely to develop heart disease within the first two years of treatment compared to women on placebo.   These women continued to be at increase risk of health disease throughout the 8 years of follow-up.

Jacques E. Rossouw, MD, chief of the NHLBI Women's Health Initiative Branch and a coauthor of the paper, added,  "Although the number of recently menopausal women who would be expected to suffer a heart attack during the first years of combination HT is small, the risk is likely to be real." In the NHLBI press release, acting director, Susan B. Shurin, MD, said, "Today, most women who take hormone therapy for menopausal symptoms begin therapy shortly after menopause.  Based on today's study, even these women appear to be at increased risk of heart disease for several years after starting combination hormone therapy."  This new data reinforces the need for women to  discuss their potential risk for cardiovascular disease and for other conditions like stroke and  breast cancer with their doctors when considering combination HT.

So what have we learned from this study?    Women who start combination HT to treat the symptoms of menopause within 10 years of menopause, should not expect the treatment to protect them from heart attacks, and may even have a possible slight increase in risk.   As with many studies, the statistical significance of the women in the study may not be sufficient to make this the final word on the topic but it is unlikely that additional information on the scale of this study will be available in the near future.

February is American Heart Month!
Posted by on February 1, 2010 - 10:21am

What is Heart Disease?

Heart Disease is a general term used to describe various diseases and syndromes of the heart and blood vessels.  Included in the definition are diseases such as coronary artery disease, heart arrhythmia, heart valve disease, heart failure, and congenital heart defects, among others.

Heart disease is the number one killer of both men and women worldwide, but may be prevented or treated with healthy lifestyle choices.  The symptoms of heart disease vary dependent on the specific condition but include chest pain, shortness of breath, fluttering in the chest, swelling in the lower limbs, and fatigue.  Symptoms of a myocardial infarction (or heart attack) tend to be different between men and women, with women experiencing more subtle symptoms such as fatigue, shortness of breath and nausea.  Consequently, it may be more difficult for health professionals to diagnose and respond to a heart attack in a woman.  In addition, recent research has shown that women suffer disproportionately than men from coronary artery disease in the small vessels (arterioles) as opposed to the larger arteries.  This may further complicate diagnosis and treatment of heart disease in women.

Causes of heart and cardiovascular disease include poor diet, little exercise, obesity, smoking, and high blood pressure, but may also be caused by congenital defects.  A healthy diet and exercise along with maintenance of blood pressure, cholesterol, and stress may help reduce the risk of heart disease.  Treatments for heart disease include lifestyle changes, medication, and in some cases surgery, and it is best treated when diagnosed early.

Resources at Northwestern for Heart Disease:

The Bluhm Cardiovascular Institute at Northwestern Memorial Hospital offers state-of-the-art treatment in all areas of cardiovascular care.  Patients receive a comprehensive, multidisciplinary approach to treatment and prevention from physicians, nurses and other healthcare providers specializing in cardiology, cardiac surgery, vascular medicine and surgery, cardiovascular anesthesiology, cardiac behavioral medicine and radiology, among others.  The Institute is comprised of six heart health centers for atrial fibrulation, coronary disease, heart failure, heart valve disease, vascular disease, and women’s cardiovascular health.  The Women’s Cardiovascular Health Center offers treatment specifically designed for women, tailoring treatment plans to optimize their specific cardiovascular needs.  The Center is also committed to promoting women’s awareness of cardiovascular health, highlighting the differences in symptoms and risk factors for women.

For more information call: (866) 662-8467 (toll free)

Northwestern Physicians/Researchers specializing in Heart Disease:

Researchers at the Feinberg Cardiovascular Research Institute are committed to exploring complex problems in cardiovascular research including molecular, cellular, stem cell and imaging technology research.   Investigators at the Institute work in areas of basic science and clinical research.  The innovative program in Cardiovascular Regenerative Medicine seeks out new ways of growing new cardiac tissue as opposed to improving function of damaged tissues.  The program provides researchers with the means to bring basic science research into use in clinical trials.  Led by Dr. Douglas Losordo, MD, clinical trials are being conducted for treatment in the areas of coronary artery disease, heart failure, and vascular disease.

For more information visit: http://www.fcvri.northwestern.edu/index.html

IWHR Highlighted Researcher

Dr. Mercedes Carnethon is an Assistant Professor of Preventative Medicine at Northwestern University’s Feinberg School of Medicine.  She earned her PhD in Epidemiology from the University of North Carolina in 2000 and joined the faculty of Northwestern in 2002.  Her research interests include the role of the nervous system on cardiovascular disease (CVD), the relationship between fitness and cardiovascular health and the effects of sleep on the risk for CVD.  She is a member of several professional societies including the American College of Epidemiology and the American Heart Association.  Most recently, Dr. Carnethon has initiated a study to evaluate how sleep duration might affect a patient’s risk for cardiovascular disease.  Previous studies have evaluated patients with major sleep disturbances, such as sleep apnea, or have used sleep deprivation to evaluate the relationship.   Dr. Carnethon’s study will more closely mirror how women and men sleep during a normal week, and compare their sleep duration to indicators of their cardiovascular health.  The study hopes to justify the recommendations for total amount of sleep that an adult might need to maintain his or her heart health.

Photo: The Heart Truth Campaign

Photo: The Heart Truth Campaign

Upcoming Public Events:

NMH Annual Cardiovascular Symposium:  Heart Health – What Smart Women Need to Know, February 24, 2010, Prentice Women’s Hospital

Don't Forget - National Wear Red Day® is February 5th!

How a Little can Lead to a Lot
Posted by on January 20, 2010 - 1:56pm
Melina Kibbe honored at White House

Melina Kibbe honored at White House

Melina Kibbe, M.D., associate professor at Northwestern's Feinberg School of Medicine, vascular surgeon at Northwestern Memorial Hospital and co-chief of the vascular surgery service and director of the Vascular Laboratory at the Jesse Brown VA Medical Center recently received the Presidential Early Career Award for Scientists and Engineers (PECASE) at the White House.   This is the highest honor given by the U.S. government to outstanding scientists and engineers who are in the early stages of their research careers.

Her current research portfolio was primed, in part, by two Pioneer Awards the Institute for Women's Health Research (IWHR) awarded Dr. Kibbe and her postdoctoral fellow in 2008 and 2009, respectively.  Her research focuses on preventing vascular injury and scarring in blood vessels following stent surgery.   It wasn't until Dr. Kibbe  ran into Dr. Teresa Woodruff,  IWHR Director, a few years ago, who asked Kibbe if she was including female animals in her research, that she gave it much consideration. After that meeting, Kibbe searched publications in her field that included sex as a variable and she found there was very little.   With her Pioneer Awards, she proposed to include male and female animal models to study the benefits of nitric oxide (NO)-based therapies following stent surgery and found that the effect was totally different between the sexes!

The Pioneer Awards were developed by the IWHR to encourage researchers to include sex and gender analyses in their studies, and the work done in the Kibbe lab demonstrates how a small amount of funding targeted to sex-based research can produce startling results and change a whole field of study.   The immeasurable aspect of the PECASE award that Dr. Kibbe received is the invaluable  publicity it will give her research.  This may help focus on the importance of including sex variables in future vascular research and open doors to new collaborations and larger funding.

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