CT scans rule out heart attacks faster

Study: CT scans rule out heart attacks faster

By MARILYNN MARCHIONE, AP Medical Writer Marilynn Marchione, Ap Medical Writer

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Wed Nov 18, 1:51 pm ET

ORLANDO, Fla. – A CT scan — a kind of super X-ray — provides a
faster, cheaper way to diagnose a heart attack when someone goes to the
emergency room with chest pains, a new study suggests.
About 6 million people each year go to hospitals with chest pain,
but only a small fraction are truly having a heart attack. CT scans are
increasingly used to diagnose problems because they give a deep,
detailed view inside the body. But they put out a lot of radiation,
which may raise a person's chances of developing cancer.
Whether these scans are worth that risk is unknown. The new study suggests that for ruling out heart attacks in the emergency room, they just might be.
The research involved 749 chest pain sufferers at 16 big medical centers around the country. These were people who did not have clear signs of a heart attack from blood tests or EKGs, but doctors are afraid to send them home without more tests.
Between
4 percent and 13 percent of such patients will have a missed diagnosis
of a heart attack, and up to one quarter of that group will die, said
the new study's leader, Dr. Kavitha Chinnaiyan, a cardiologist at William Beaumont Hospital in suburban Detroit.
"One
of the most common reasons for an emergency room physician to be sued
is that they send a patient out and then they come back with a heart
attack," said Dr. Sidney Smith, a former American Heart Association president from the University of North Carolina at Chapel Hill. "It is a big problem."
In
the study, half of the patients were given CT scans and the rest,
standard imaging tests with a radioactive dye. Of the CT patients, 82
percent were found to have clear arteries and were discharged
immediately. In the other group, 89 percent were determined to have
normal arteries and sent home.
The portion of
patients who needed a definitive but invasive test — angiography — to
see whether they should have an artery-opening balloon angioplasty procedure or bypass operation was the same — 6 to 7 percent of each group.
The big difference was in cost and time.
CT
scan patients were diagnosed in about three hours versus more than six
for the others. Their testing also cost less — $2,137 on average versus
$3,458 for standard screening.
"It's equally
safe, it's faster and it's cheaper," said Chinnaiyan, who has no
financial ties to imaging companies. She reported results Wednesday at
a heart association conference in Florida.
The
study had partial support from Bayer Pharmaceuticals, which makes
products used in heart imaging. A few doctors involved in the study
have had research grants from Bayer or a firm that makes imaging
equipment.
"These are promising results" for CT scanning, said Smith, who had no role in the work. "They were able to identify a certain group that did not need to be admitted."
Radiation
remains a concern, though. A CT scan of the chest involves 10 to 15
millisieverts (a measure of dose) versus 0.01 to 0.15 for a regular chest X-ray, 3 for a mammogram and a mere 0.005 for a dental X-ray.
On the other hand, people with chest pain
often are admitted to a hospital and then given repeated tests over a
number of days that can add up to a high cumulative radiation dose.
"If you had a CT scan and it showed you were fine, you would not get any of that radiation," said Dr. Mariell Jessup of the University of Pennsylvania, who led the conference's scientific panel.
A more definitive picture of risks and benefits will come from a big study just getting under way, headed by Duke University's Dr. Pamela Douglas.
The
$32.5 million federally funded study is the largest ever for heart
imaging and the only one to look at how various imaging tests
ultimately affect the rates of death, heart attack, stroke,
hospitalization and other factors. It will enroll 10,000 people in the
United States and Canada.
A big question, Douglas said, is: "As people get more and more radiation medically, are we adding up some new cases of cancer?"


Heart conference: http://www.americanheart.org
http://news.yahoo.com/s/ap/20091118/ap_on_he_me/us_med_heart_scans