Stent Research at Emory: First Results of SIRIUS Trial Bolster Evidence
New Treatment Keeps Arteries Open
Stents are tiny
wire mesh tubes used to prop arteries open after angioplasty clears
them of potentially heart attack causing plaque. Unfortunately, in many
cases, stented arteries eventually close back up with fatty deposits,
a process called restenosis. Now there's hope restenosis can be eliminated
or greatly reduced in the not-too-distant future, thanks to stents coated
with pharmaceutical agents that prevent excess tissue growth.
The first preliminary findings
of the landmark SIRIUS study, just released at the Paris Course on Revascularization
(PCR), reveal a remarkably decreased rate of restenosis in patients
who received drug coated stents, according to Emory interventional cardiologist
John Douglas Jr., M.D., Primary Clinical Investigator for the study
Sponsored by Johnson & Johnson's
Cordis Corporation, the Sirius research is an ongoing study at the Emory
Heart Center and 52 other U.S. medical centers. The randomized, double
blind clinical trial involves about 1,000 patients who have received
either a plain metal stent or one coated with the pharmaceutical agent
rapamycin. In data released on 400 patients participating in the Sirius
trial, researchers concluded that only two percent who received the
CYPHER(TM) drug-eluting stents experienced restenosis within arteries.
In approximately nine percent of study participants, there was restenosis
found near the stent edges. However, with non-drug coated metal stents,
reclogging occurs in approximately 25 to 30 percent of patients.
The drug coating does not
kill cells, but allows the endothelium (layer of cells lining vessel
walls and the heart) to cover the stent. "This is important because
the stent becomes coated with cells and incorporated into the heart,"
says Dr. Douglas, who implanted the first coronary artery stent in the
U.S. at Emory Hospital in l987.
He points out that without
this cell covering, a stent may promote blood clot formation when the
body "reads" the device as foreign material. "In fact, that's one of
the limitations of radiation treatment for preventing the renarrowing
process in arteries. Radiation prevents the growth of tissue over the
stent and that can up the risk for blood clot formation there later
and lead to heart attack. The drug coated stent may be a solution to
this problem," he notes.
" We are very excited about
the results of the Sirius trial, so far. We believe the rapamycin coated
stent may prove to be a major breakthrough in defeating restenosis after
stenting and could possibly FDA approved and ready for interventional
cardiologists to use by 2003," Dr. Douglas says.