Women
With Chest Pain Gain Insight With New Test
A new, noninvasive
test shows potential for helping women with unexplained chest
pain, according to a study published in the medical journal
Circulation: Journal of the American Heart Association.
The test points out
those women whose hearts are deprived of oxygen -even when standard
tests show no coronary artery disease.
Women often seek medical
help for chest pain, sometimes undergoing coronary angiography.
But in almost half of all such women, there is no coronary artery
disease found.
Tests
Open New Avenues
Now scientists suggest
that blockages in the smaller, slender arteries that feed the
heart muscle - blockages that cannot be spotted on standard
tests - might be at fault.
"We have seen that
many of these women are admitted to the hospital for chest pain,
and undergo angiography to look for coronary artery disease
[CAD] behind the angina, yet no such disease is found,"
says Dr. Gerald M. Pohost, at the Keck School of Medicine of
the University of Southern California.
"Our results indicate
that in many of these women, something is keeping the heart
from getting the oxygen it needs," says Dr. Pohost, senior
author on the study. "We suspect microvascular dysfunction
or disease."
Prompted by symptoms
such as chest pain, or angina, more than a half million US women
underwent coronary angiography to look for CAD in 2001.
Yet nearly half of
women with chest pain who undergo coronary angiography are found
to have no significant CAD, posing a puzzle for physicians.
CAD is a disease of
the arteries that supply blood to the heart muscle. Over time,
as fatty materials collect in the vessels that supply the heart,
the artery walls thicken and narrow the space where blood can
flow, depriving heart tissue of oxygen.
The study was a part
of the Women's Ischemia Syndrome Evaluation,
or WISE, study. WISE is a four-center study of women undergoing
coronary angiography for chest pain or suspected myocardial
ischemia.
The researchers compared
352 women with CAD to 74 other women without it. The CAD-free
women underwent an imaging scan called phosphorus-31 nuclear
magnetic resonance spectroscopy, which is done completely from
outside the body.
The technique simply
required that women squeeze a handgrip while lying inside an
MRI unit. Nuclear magnetic resonance spectroscopy technology
enabled scientists to measure levels of two phosphates found
in heart tissue.
This was done once
while women were at rest and again while they were squeezing
the handgrip (experiencing physical stress).
Investigators then
compared the before-and-after levels of the two phosphates.
Researchers saw that
the ratio of the two phosphates (phosphocreatine and ATP) declined
significantly in 14 of the 74 CAD-free women when they squeezed
the handgrip. A big drop in the ratio is abnormal and a sign
that heart tissue is not getting enough blood, Dr. Pohost explains.
Investigators wanted
to see whether the abnormal results were linked to women's cardiovascular
health.
Researchers
Follow Women's Experiences
Over the next three
years, they tracked how many of the women experienced a cardiovascular
event such as a heart attack, stroke, or hospitalization for
a blood clot or unstable angina.
They found that 87
percent of the CAD-free women with normal magnetic resonance
spectroscopy results stayed free of cardiovascular events.
But 57 percent of
the CAD-free women with abnormal magnetic resonance spectroscopy
results had no events. That is not much better than the women
who had been diagnosed with CAD: 52 percent of them avoided
cardiovascular events during that time period.
Most of the events
were hospitalizations due to unstable angina, and many of the
women with abnormal magnetic resonance spectroscopy results
experienced repeated, fruitless angiography procedures to find
the cause of the angina during the three-year follow-up.
In the clinic, Dr.
Pohost and fellow cardiologists use standard angina therapies
to treat chest pain in these CAD-free women, he says.
The study suggests
that magnetic resonance spectroscopy could be widely used to
evaluate women complaining of chest pain, and even may reduce
the number of women undergoing repeated coronary angiography
procedures.
Always consult your
physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
American
Heart Association
Centers
for Disease Control and Prevention (CDC)
Everyday
Choices, AHA, ADA, and ACS
Go
Red for Women Campaign, AHA
HealthierUS.Gov
National
Heart, Lung, and Blood Institute (NHLBI)
National
Institutes of Health (NIH)
National
Library of Medicine
US
Health and Human Services |
October
2004
Women
With Chest Pain Gain Insight With New Test
Tests
Open New Avenues
Researchers
Follow Women's Experiences
Heart
News Round-Up
Online
Resources
Heart
News Round-Up
Mechanical
Pump Aids Heart
The most seriously ill congestive heart failure patients live
longer and have a better quality of life if implanted with a
heart pump, researchers report in Circulation: Journal
of the American Heart Association.
End-stage heart failure
occurs when the heart is so weak, it can no longer pump enough
blood and nutrients to the body’s organs.
Standard treatment
includes lifestyle modification, and medications that strengthen
the heart’s pumping ability, ease the heart’s work
by relaxing blood vessels, and help the body eliminate excess
fluid.
If symptoms are life-threatening
despite optimal drug treatment, a heart transplant is considered.
However, there are fewer than 2,500 hearts transplanted each
year in the US, and 500,000 to 800,000 patients have advanced
heart failure, according to the American Heart Association.
The left ventricular
assist device (LVAD) is a newer treatment option. This mechanical
pump helps maintain the pumping ability of a heart that cannot
work effectively on its own.
LVADs were originally
conceived as a “bridge to transplant” - a temporary
device to use while patients waited for a heart transplant. Now
they are now being investigated as permanent “destination
therapy” for patients ineligible for transplant instead
of as a temporary measure.
“The benefit
of LVAD was most dramatic in the sickest people, those who will
have the worst outcome without the device," says Dr. Lynne W.
Stevenson, co-director of the cardiomyopathy and heart failure
program at the Brigham and Women’s Hospital in Boston.
Lab Study
Heralds the Future
Researchers are on track one day to hand cardiologists
the first means ever to pinpoint plaque deposits in the arteries
of patients that appear poised to cause heart attack or stroke
- and without surgery, biopsy, or other invasive procedure.
Biochemist Dr. Alexei
A. Bogdanov Jr. and colleagues at Massachusetts General
Hospital and Harvard Medical School are using a cellular model
in the lab and magnetic resonance imaging (MRI) to develop their
non-invasive method.
They aim to detect
and trace elevated levels of an enzyme that other research groups
have linked to plaque instability and cardiac risk.
Dr. Bogdanov emphasizes
much work remains before the technique could reach the clinic.
However, the results were so encouraging that he presented
them at the American Chemical Society meeting.
If physicians have
early warning that a particular plaque is unstable, they may
be able to prioritize or target their patient’s treatment
to that artery, perhaps averting an attack or at least minimizing
its damage.
Drug-Coated
Stents Studied
The new drug-coated stents, flexible tubes designed to keep
arteries open, reduce the risk of heart attacks but do
not provide greater life expectancy in the months
after they are implanted than traditional stents, according
to a study reported in the medical journal Lancet.
Analyzing data on
11 trials that compared results in 5,000 patients who got either
the traditional bare-metal stents or the drug-eluting
stents, researchers at McGill University in Montreal say the
newer devices reduce the risk that arteries will close up again
and the occurrence of "major adverse cardiac events," such as
the need to perform bypass surgery.
But the overall death
rate and the incidence of heart attacks were almost identical
for patients who got the coated or bare stents, the analysis
found.
A stent is implanted
after balloon angioplasty, a procedure that widens arteries
in which blood flow is impeded by fatty deposits. Coated stents,
which release drugs that help keep arteries open, were introduced
about five years ago and are now widely used.
It is not surprising
that the analysis found no effect on the risk of death because
"major events frequently are associated with disease in other
arteries that do not receive stents," said Dr. Sidney Smith,
chief of cardiology at the University of North Carolina and
a spokesman for the American Heart Association.
It is a "very helpful
study because it demonstrates the benefits of drug-eluting stents
over the short term," Dr. Smith says. "If you have a drug-eluting
stent, you are less likely to go back to the hospital because
of restenosis [artery blockage] or an adverse cardiac event."
Always consult your
physician for more information. |
