Study finds arteries remain
clear 6 months after radiation
Coronary arteries remain open six months after mild irradiation in 90
percent of postangioplasty patients, reported Emory's Spencer King, principal
investigator for "Beta Radiation for Restenosis Trial" (BERT-1),
at the American Heart Association Scientific Sessions Nov. 10.
These findings suggest radiation treatment blocks restenosis-the process
by which coronary arteries widened by balloon angioplasty eventually renarrow.
BERT-1 is the first human trial to test the use of low doses of locally
delivered beta radiation for preventing restenosis, which occurs in about
one-third of patients who undergo angioplasty. A phase III clinical trial
based on BERT-1 preliminary data is now evaluating the technique in 1,100
patients at 26 medical centers in North America and Europe.
During the study, specially fitted catheters delivered minute amounts
of radiation to angioplasty sites in the coronary arteries of 35 patients.
The researchers measured the diameter of vessel openings before angioplasty,
just after angioplasty and at six months' followup. Subjects' vessels were,
on average, 73 percent closed before angioplasty, 25 percent closed just
after angioplasty and 25 percent closed at the six-month followup.
The increase noted in the diameter of the vessel's opening several months
after angioplasty when compared to the opening just after angioplasty is
referred to as "late loss." The team found radiation reduced the
late loss and late-loss index by 85-90 percent.
"Using this system, intracoronary beta radiation was feasible without
disrupting the normal [cardiac catheterization] lab routine or producing
complications," King and his colleagues reported. "As illustrated,
the usual late loss was eliminated in most patients."
During angioplasty, a balloon-tipped catheter is threaded through arteries.
As the balloon expands, it pushes plaque against vessel walls and frees
blood flow. Unfortunately, that same lifesaving procedure (as well as the
use of tiny metal stents to prop open vessels) triggers an inflammatory
response in about one-third of patients, putting them at risk for restenosis
and further cardiac complications.
About 500,000 coronary angioplasties are performed domestically each
year, and another 500,000 are performed annually outside the United States;
so roughly 300,000 persons are at risk each year for restenosis after angioplasty.
In the United States, repeat angioplasties cost billions of dollars.
King directs the Gruentzig Cardiovascular Disease Research Center and
is professor of medicine at the School of Medicine. Other Emory researchers
included Larry Klein, Ron Waxman, Keith Robinson, Kris Anderberg, Judy Scruby
and Ian Crocker, all of the School of Medicine. BERT-1 was funded by the
National Institutes of Health.
Analyses show better recovery at lower costs
Sicker heart patients are more likely to survive coronary intervention,
are spending less time in the hospital recovering and are doing better once
at home-all this at about one-third the cost of similar care in the 1980s,
according to cost benefit analyses presented by William Weintraub, associate
professor of Medicine, at the American Heart Association Scientific Sessions,
Weintraub and his Emory colleagues profiled all 12,265 patients who underwent
coronary artery bypass graft surgery at Emory and Crawford Long hospitals
from 1988-96 as well as all 12,978 patients who received balloon angioplasty
at Emory from 1991-96. While the numbers of the two analyses differ, the
trends uncovered do not.
The researchers report that hospital costs in 1996 dollars fell 30 percent
in the coronary bypass surgery analysis (from mean per-procedure costs of
$22,689 in 1988 to $15,987 in 1996). Other statistically significant changes
noted during that time period indicate that patients were older and more
likely to have high blood pressure, to have had a heart attack, to have
diabetes and to have had congestive heart failure (6.5 to 7.9 percent).
Death rates in the study population decreased from 4.7 to 2.7 percent.
"Over the last several years the patients have become sicker and
by several measures outcome has improved," Weintraub reported. "These
changes have been accomplished while at the same time resource use has decreased
as measured by length of stay (down from 2.8 days in 1991 to 1.9 days in
1996) and cost. The decrease in cost was 26 percent, almost entirely in
the last two years while stent utilization increased. Whether these favorable
trends can continue or if care is already optimal remains to be seen."
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