This is very good news for heart patients and particularly everyone
else over twenty. We can expect to see a
simple diagnostic test which establishes the presence of lesions putting the
patient at risk. Since 90% of all men by
the age of sixty have circulatory disease established and are at risk sooner or
later, it is also pretty apparent that it all started much sooner.
Thus an annual check up, usually conducted by most men every few years
anyway is the ideal point to run this potential test. Since women develop the same problems with a
lag of a decade, they should begin with the onset of menopause.
The good news is that this is information we need to know sooner than
later and it is critical to avoid the first heart attack. The death rate there is fifty percent and it
catches men with at least a decade left of productive working life ahead of
them. A warning test effectively ends
that problem and also allows superior protocols to be developed to fight the
disease.
Researchers closer to a test to predict heart attacks
Using a blood sample to detect circulating endothelial cells that
sloughed off damaged vessel walls could help save at-risk patients who had
normal stress tests.
Normal, healthy circulating endothelial cells, left, are smaller and more
uniform than CECs from heart attack patients, right.(Scripps Translational
Science Institute / March 19, 2012)
By Eryn Brown, Los Angeles Times
March 21, 2012, 5:29 p.m.
Doctors are one step closer to a simple test that could predict whether
a patient is about to have a heart
attack — by using a blood sample
to detect cells that have sloughed off of damaged blood vessel walls.
The finding, published Wednesday in the journal Science Translational
Medicine, could potentially address "the greatest unmet need" facing
cardiologists, said lead author Dr. Eric Topol, a cardiologist at the Scripps
Translational Science Institute in San Diego. Though physicians can easily
detect a heart attack that's already underway, every year tens of thousands of
patients walk away from the doctor's office after having passed a stress test,
only to suffer a devastating heart attack within a few weeks.
Topol called the phenomenon the "Tim
Russert syndrome,"
referring to the newsman who died of a heart attack in 2008, weeks after
undergoing a stress test with apparently normal results.
"When someone is having the real deal, we know that," Topol
said. "The real question is, is something percolating in their artery?
We'd like to prevent the heart attack from happening," or mitigate its
effects with drugs.
The new technique involves tracking a type of cell in the blood called
a circulating endothelial cell.
Endothelial cells create a wrapper that lines the inside of blood
vessels. When the vessel is damaged, endothelial cells break away and enter
the bloodstream.
Healthy people have very few of these circulating cells. But a person
with mild cholesterol buildup can develop a crack in an artery wall that
disrupts the lining and sends them into the blood.
A heart attack occurs when an area of plaque ruptures in an artery,
forming a blood clot that blocks blood flow to the heart, resulting in heart
tissue damage.
Ruptures resulting from mild cholesterol buildups can lead to
particularly deadly heart attacks, said Dr. Douglas Zipes, a cardiologist at
the Indiana
University School of Medicine in
Indianapolis, because patients with such blockages are often asymptomatic, and
— unlike people with larger blockages — are unlikely to have developed new
blood vessels that can help bypass the obstruction.
Knowing that the endothelial lining has been damaged before a blood
clot grows might allow physicians to predict onset of a heart attack or stroke,
said Zipes, who was not involved in the study.
Scientists reported the detection of circulating endothelial cells in
heart attack patients in 1999 but didn't have the technology at that time to
isolate the cells and properly study them. Newer tools allowed the Scripps
team, working with a variety of institutions in the San Diego area, to examine the
cells more closely.
The team studied blood samples from 50 patients with confirmed heart
attacks and 44 healthy control patients. First they established that the heart
attack patients had more circulating endothelial cells in their blood — 19
cells per milliliter, on average, versus four in healthy individuals.
The researchers next explored whether there were differences between
the circulating endothelial cells of healthy people and those of heart attack
patients. There were: Cells from the heart attack group were clustered together
and large, and had multiple nuclei (organelles in the cell that hold the DNA).
Topol attributed the bizarre appearance of the cells to the effects of
profound inflammation in the damaged arteries.
"These cells shouldn't be in the blood. If you have them, you have
trouble lurking," he said.
Cardiologists not involved in the study said they were excited by the
findings.
"We do prostate tests, we do cholesterol tests," said Zipes.
"Perhaps we should have [circulating endothelial cell] tests too, in
people at risk."
Dr. Robert Harrington, a professor of medicine at Duke
University, added that the research
is helping scientists understand the biology of heart attacks. But he cautioned
that more study was needed to flesh out and confirm the results, and to prepare
a test for patients. The methods presented in the Scripps research may be too
complicated for use in a doctor's office or an emergency room, he said.
One key detail yet unknown is how long before a heart attack the
circulating endothelial cells appear.
"Is it a day before? A week before? That would be good to
understand," Harrington said.
Topol said research into the abnormal cells had allowed his team to
obtain a genetic signature for them. That should help
development of a simple blood test, he added, perhaps within a couple of years.
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