|Study Findings Challenge Current Clinical Practice
Clinical Trial Results Find Late Angioplasty after Heart Attack
Offers No Advantage Over Standard Drug Therapy
Chicago — About one-third of heart attack
patients do not receive treatment to open blocked arteries within
the recommended 12-hour timeframe after a heart attack. Treatment
such as angioplasty or clot-busting drugs may not be given because
patients arrive at the hospital too late. For years it has been
thought that late balloon angioplasty of these patients' arteries,
if they are totally blocked, is still beneficial and might prevent
future heart failure, another heart attack, or death. However,
according to the results of a large international multi-center
clinical trial, stable patients who had angioplasty plus stenting
three to 28 days after a heart attack did no better than patients
on medical therapy (primarily drug treatment) alone.
The Occluded Artery Trial (OAT) was funded by the National Heart,
Lung, and Blood Institute (NHLBI) of the National Institutes of
Health and is being presented today at a late-breaking clinical
trial session of the American Heart Association's Scientific Sessions
2006. The study is also published online on November 14 in the
New England Journal of Medicine and in the journal's December 7
"These results challenge the long standing belief that opening
a blocked artery is always good. Instead, the study suggests that
late angioplasty is unnecessary in this circumstance. The good
news is there have been tremendous advances in drug therapy for
heart attack patients. Drug thereapy is an important treatment
option," said NHLBI Director Elizabeth G. Nabel, M.D.
"Our findings indicate that routine late opening of the heart
attack related coronary artery is not appropriate and should be
reserved only for certain patients such as those who are unstable
or continue to have chest pain following a heart attack. These
results should lead to lower rates of unnecessary coronary interventions
in this specific group of stable patients," said Judith Hochman,
M.D., OAT study chair and Harold Snyder Family Professor of Cardiology,
Clinical Chief of Cardiology and Director of the Cardiovascular
Clinical Research Center, New York University School of Medicine
in New York City.
"In general, there is considerable individual variation in the
need for angioplasty or bypass surgery in patients who have coronary
Hochman expressed concern about a trend in the OAT study toward
more heart attacks in the angioplasty group. Although the trend
was not statistically significant, she said, it needs to be studied
and the patients followed for a longer time to determine if the
trend continues or whether other trends emerge. According to Hochman,
it is not known whether the increase in heart attacks will lead
to an excess risk of heart failure or death or reduced quality
The OAT trial sought to determine whether performing balloon angioplasty
in a totally blocked coronary artery related to a heart attack
three to 28 days after the heart attack would benefit stable patients
and reduce the risk of future cardiovascular complications. In
angioplasty, a thin tube with a balloon or other device on the
end is first threaded through a blood vessel in the arm or groin
(upper thigh) up to the site of a narrowing or blockage in a coronary
artery. Once in place, the balloon is then inflated to push the
plaque outward against the wall of the artery, widening the artery
and restoring the flow of blood through it.
In OAT, a total of 2,166 patients in 27 countries were randomly
assigned to routine angioplasty with stenting combined with drug
therapy or to drug therapy alone. Most patients had blockages in
one coronary artery only.
Drug therapy for both groups included aspirin, blood-pressure
lowering ACE inhibitors, beta blockers, cholesterol-lowering therapy,
and clopidogrel, a drug given to patients with stents to prevent
blood clots. Patients assigned to undergo angioplasty were given
the procedure within 24 hours of treatment assignment. Stenting,
placing a metal mesh tube in the artery to keep it open, was recommended
for the patients given angioplasty. The primary endpoint or measured
result of the 5-year study was a composite of death from any cause,
another heart attack, or hospitalization for severe (Class IV)
The OAT results found no statistically significant difference
in major cardiovascular events between the two groups over an average
of three years and up to five years. At four years, the rate of
death, heart attack, or serious heart failure was 17.2 percent
in the angioplasty group compared to 15.6 percent of the medical
therapy group. The results were consistent across study sites located
in the United States and in other countries.
The OAT investigators offer a possible explanation for the trend
toward more heart attacks in the angioplasty group. According to
Hochman, when someone has a 100 percent blocked artery, the heart
muscle may still be somewhat protected by small vessels that provide
blood flow from the other coronary arteries. "These vessels are
so small that if an easier blood flow path is reestablished via
angioplasty, they close down, either temporarily or permanently.
If the artery that had the angioplasty re-closes, these small vessels
would not be rapidly available to supply blood to your heart muscle
at the time of your next heart attack," she said. In addition,
Hochman said that it is possible that some heart muscle damage
due to dislodging of clots and plaque at the time of the angioplasty
procedure counteracts other potential long-term benefits.
Each year, about one million people in the United States have
a heart attack and half of them (515,000) die. About one-half of
those who die do so within 1 hour of the start of symptoms and
before reaching the hospital. About one million angioplasty procedures
are performed in the US each year.
"There's an important public health lesson to be learned from
the OAT trial results: seek care very early after heart attack
symptoms begin because that's when there is a great deal of benefit
from angioplasty," said Alice Mascette, M.D., chief of NHLBI's
Heart Failure and Arrhythmias Branch and member of the OAT study
"And we should not forget that controlling the risk factors for
heart disease — such as high cholesterol and high blood pressure — can
go a long way toward preventing heart attack in the first place."
To interview Dr. Nabel, or study co-authors Dr. Mascette or Dr.
George Sopko of NHLBI, contact the NHLBI Communications Office
at 301-496-4236; to interview Dr. Hochman, contact Pamela McDonnell,
Office of Public Affairs, NYU School of Medicine at 212-404-3555.
Part of the National Institutes of Health, the National Heart,
Lung, and Blood Institute (NHLBI) plans, conducts, and supports
research related to the causes, prevention, diagnosis, and treatment
of heart, blood vessel, lung, and blood diseases; and sleep disorders.
The Institute also administers national health education campaigns
on women and heart disease, healthy weight for children, and
other topics. NHLBI press releases and other materials are available
online at: www.nhlbi.nih.gov.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov.