Radiation Therapy Keeps Arteries Unclogged

	November 1, 1999 - About a million people each year in the USA have
a procedure called angioplasty, in which plaque is cleared from clogged heart
arteries using a balloon-like device. But in 1/4 - 1/3 of these patients, the
arteries become clogged again later, requiring additional surgery.
	A new study suggests that if these patients were to spend an extra 30-
45 minutes on the operating table to receive low-dose radiation therapy, they
might fare much better.
	The study was done with 252 patients at 12 medical centers in the USA.
Researchers studied repeat angioplasty patients because they are at higher
risk for relapse. Results showed that low-dose radiation therapy reduces by
41% the chances that such patients will need angioplasty a third time.
	After a patient had a standard angioplasty, a radiologist - with the
aid of a cardiologist - inserted a catheter into the cleared-out artery.
Inside the catheter was nylon ribbon with radioactive seeds attached to it.
"Because the seeds are attached to a ribbon, they're not floating around in
the patient," said lead researcher Tripuraneni. "We know how many there are,
what the distance is between them and the activity of the radiation seeds. So
based on that, I can accurately calculate the dose I want to give."
	The seeds were removed after 20 minutes. The procedure took a total of
30-45 additional minutes. In the study, 131 of the patients had the
radioactive seeds while the rest had non-radioactive seeds inserted into
their cleared arteries. After 9 months, the coronary arteries of 1/3 of the
patients getting radioactive seeds had re-clogged, while more than 1/2 of
those getting fake seeds re-clogged.
	"The initial results are very encouraging," said Dr. Robert Schwartz,
from the Mayo Clinic at Rochester. But he cautioned that the issue of adequate
clotting control must be dealt with and that radiation must be proven to keep
arteries open over the long-term.
	Clots did appear in about 6% of patients getting radiation who
received a stent to keep the artery open. Such patients would require blood
thinners to prevent a clot. No clots formed in patients who did not require a
stent.