Weak Evidence Backs Most Heart Guidelines, Report FindsExperts agree that
field needs more rigorous trials to aid doctors

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http://www.nlm.nih.gov/medlineplus/news/fullstory_80997.html (*this news
item will not be available after 05/26/2009)

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HealthDay*Wednesday*, February 25, 2009

[image: HealthDay news image]TUESDAY, Feb. 24 (HealthDay News) -- A majority
of the guidelines for cardiac care issued by the American Heart Association
and the American College of Cardiology are not supported by the kind of
gold-standard evidence that doctors respect most, a new study finds.

That conclusion does not come from heretics crying in the wilderness. One
author of the report, published in the *Journal of the American Medical
Association,* is Dr. Sidney Smith, a professor of medicine at the University
of North Carolina, a past president of the heart association and former
chairman of the AHA/ACC Guidelines Task Force.

The findings were quickly endorsed by Dr. Timothy J. Gardner, current AHA
president.

"There are many situations we encounter where we don't have as strong
evidence for the guidelines as we would like to have," said Gardner, who is
medical director of the Center for Heart & Vascular Health at the Christiana
Care Health System in Delaware. "There haven't been enough randomized
trials."

And too many of the carefully controlled trials now being done are financed
by pharmaceutical companies, said Dr. Pierluigi Tricoci, a cardiologist at
the Duke Heart Center and another member of the team that did the study.

"Most major clinical trials are sponsored by the pharmaceutical industry,
because they want to bring products to market," Tricoci said. "We don't have
a source of funding for those situations that the pharmaceutical industry
might not be interested in. We should not be surprised that the
pharmaceutical industry is not interested in trials from which they might
not make money."

Tricoci was an originator of the project that looked at the evidence
supporting cardiac care guidelines, which have multiplied in number in
recent years. The project investigators examined 53 guidelines on 22 topics,
with a total of 7,196 recommendations.

The evidence for those recommendations was graded A to C. A recommendation
got an A if its evidence came from multiple controlled trials, a B if
evidence came from one randomized trial or non-randomized trials, and a C if
the recommendation was based on clinical judgment, with little or no
scientific evidence.

Just 12 percent of the current recommendations got a grade of A, and 45
percent earned a C.

Those grades have been dropping in recent years, the study found. Though the
number of recommendations increased by 48 percent over the 24 years covered
by the study, there has been a steady shift toward lower levels of
supporting evidence.

The lack of evidence is greatest in treating disorders of the heart valves,
Tricoci said. "This is the area with the highest number of level C
recommendations," he said.

The findings do not mean that cardiologists should ignore the guidelines,
Tricoci said. "What the paper says is that cardiologists in daily practice
face several situations where there is not scientific evidence and not a
consensus about the best approach," he said. "This quantifies the gap in
knowledge that I'm sure every cardiologist is familiar with every day."

One example of the uncertainty they face is the recommendation for
prescribing the clot-preventing drug Plavix for someone who has had a stent
implanted after an artery-opening procedure such as angioplasty, Tricoci
said.

"That is uncertain even in the guideline," he said. "It says, 'for at least
a year,' but there is no trial that shows how long Plavix should be given."

"There are lots of issues raised by this discussion," Gardner said. "To us,
it is a validation of the usefulness of guidelines, plus pointing out that
we don't have as many multi-center randomized trials as we would like to
have."

But existing guidelines, Gardner said, are basically the best that can be
set at this time. "As we get into more areas of medical science and patient
care, sometimes we get into areas where there are not primary clinical
trials," he said. "When guidelines are based on clinical trials, which is as
good evidence as can be obtained, they can be trusted quite
enthusiastically. When we are forced to rely on expert opinion, we need to
respect the fact that future trials may provide further information."

The report carries a plea for more government support of clinical research,
Tricoci said, a view supported in a statement from Dr. W. Douglas Weaver,
head of cardiovascular medicine at Henry Ford Hospital in Detroit and
president of the American College of Cardiology.

"We must continue to diligently apply the best evidence available, but we
need more research," Weaver said. "This paper is a valuable and important
message to the new administration, Congress and the nation about the need to
invest more in science, medical evidence and clinical comparative
effectiveness."


HealthDay Copyright (c) 2009 ScoutNews, LLC <http://www.healthday.com/>. All
rights reserved.

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