The Heart of the Matter: Cardiology News Tips
THE HEART OF THE MATTER: CARDIOLOGY NEWS TIPS
Exercise is Good, But Why?
Note to editors: The photograph below of Dr. William Kraus and a
study participant working out at Duke's Center for Living is available
on the web at ftp://184.108.40.206/pub/ slugged "tips0199."
Exercise is good for one's health. Of that there is little
dispute. But how often should you exercise, and how hard, is another,
and more difficult, question to answer. Scant data exist on the optimum
exercise regimen to improve cardiovascular health, as well as what
actually happens within the body as a result of exercise.
Duke cardiologist Dr. William Kraus believes that answers to
these questions will come from a new trial beginning this month at Duke
University Medical Center.
"For more than two decades, the party line has been exercise is
good," Kraus said. "But in reality, there is no good scientific data on
how often one should exercise and at what intensity. The current
recommendations are basically to do something, anything. I think we can
do better than that."
With a $4.3 million grant from the National Heart Lung and
Blood Institute (NHLBI), Kraus and colleagues will put 360 overweight
people with high lipid levels through various levels of exercise.
Throughout the study, researchers will measure levels of lipids in the
blood, document the changes in muscle through needle biopsies and use a
new method for measuring biochemical signaling between cells.
"We know that physical activity can improve the way the body
metabolizes carbohydrates, glucose and fats, which in turn reduces the
risk of heart disease," Kraus said. "This trial should provide us with
clues about what actually happens on the cellular level as these
benefits accrue. Our hypothesis is that exercise causes changes in
peripheral muscle and the capillaries supplying blood to that muscle
that lead to better metabolism of lipids in the blood. "By the
conclusion of the trial, we should be able to design optimal training
routines to improve the cardiovascular health of our patients," he
Grow a Vessel, Ease a Heart
It's a simple idea, really. If a vessel in a heart is blocked,
then grow a new one around it or from the other side. The heart already
has the ability to do this. When muscle cells are deprived of oxygen,
they display receptors designed to latch on to circulating growth
factors - a natural attempt to provide new channels for blood flow. But
there isn't enough growth factor protein generally available to
accomplish this desperate attempt by a dying heart.
Now, cardiology researchers are testing ways to give the heart
what it wants. They are injecting growth factor directly into the
hearts of ailing patients through the use of a thin catheter at the
time of cardiac catheterization. "We want to let the body do what we
know it has the capability of doing," says Dr. Brian Annex. "It's an
entirely novel approach."
Annex and Dr. Kevin Landolfo are part of a Duke team of
cardiologists and surgeons who are exploring the use of a protein
called vascular endothelial growth factor (VegF) to help restore blood
flow to the heart. They are involved in several randomized, blinded
national trials, and Duke and its sister hospital, the Durham VA, are
the second leading enroller of patients in the largest of these trials.
Although the results of that study won't be available until
March, Annex says he can't help but "feel excited" about the potential
of this therapy. "I've seen some very dramatic responses in our trial,
including one patient who went from popping 10 nitroglycerin pills
daily to giving them up entirely. If it works, angiogenesis therapy
will be an enormous new tool for medicine, not only to help the heart
but many organ systems."
Medicate Menopause - or Not?
For years, women have taken medications for menopause because
they, and their physicians, relied on preliminary studies that
suggested hormone replacement therapy (HRT) is good for the bones,
heart, and hot flashes. But new research is casting doubt on the
ability of supplemental hormones to prevent heart disease, especially
in women who already have cardiac problems.
A study released last summer found that women with diagnosed
heart problems who took HRT were more likely to develop clots in their
veins as well as gallbladder disease, and that there was no benefit in
preventing death or heart attacks after more than four years of
treatment. The surprising finding raises a question that both
physicians and women are still wrestling with: Are the possible
long-term benefits of HRT worth the risks?
It's a tricky issue because it depends on the age and health of
the patient, as well as the expected benefit, says Duke cardiologist
Dr. Kristin Newby, who participated in the research. "Based on what we
know about the study, we don't have the data to recommend hormone
therapy to prevent coronary events.
"But there are a lot of other reasons to consider HRT, such as
to help with perimenopausal symptoms, with bone loss, and, potentially,
to help prevent such cognitive deficits as Alzheimer's disease," Newby
says. "It really is an individual decision, at this point."
A definitive examination of HRT's long-term effect in women who
do not have heart disease when they start therapy isn't expected until
2005, with completion of a study of more than 160,000 menopausal women.
Globally, Women Heart Patients Don't Fare as Well
Women in Latin America, and to a lesser extent, those in Eastern
Europe, receive aggressive treatments for potential heart attacks less
frequently than men, and when they do receive this care, it tends to be
administered later. In these regions, the incidence of death from heart
disease is higher in women.
But in the more industrialized areas of the world, like North
America and Western Europe, women and men receive practically the same
treatment and have similar outcomes. These findings are a result of an
analysis of data collected during a recent 27-nation heart drug trial
involving more than 10,000 patients coming into emergency rooms with
symptoms of a heart attack. In the process of gathering data about the
drug, researchers also collected information on whether or not patients
received aggressive diagnostic or treatment procedures such as cardiac
catheterizations, angioplasties, or coronary artery bypass procedures,
and how well they did.
"These data give us a snapshot of the state of heart care,"
said Lisa Berdan, a researcher at the Duke Clinical Research Institute
(DCRI). "The disparity in the treatment of women may not be solely a
resource issue, but may involve cultural factors as well."
Previous international trials have shown that compared with
men, women who present with acute coronary syndromes (symptoms that may
lead to a heart attack) tend to be older, have more concurrent medical
problems, and have more risk factors for heart disease.
"This explains why women are worse off when they arrive at
hospital, but it doesn't explain the differences in treatment," Berdan
said. "In North America and Western Europe, for example, women seemed
to do as well as men after aggressive treatment."
When the researchers then looked at when women received these
aggressive diagnostic and treatment procedures, they found that in
Latin America and Eastern Europe, these procedures were performed