The U.S. Food and Drug Administration recently
approved a new type of drug-eluting coronary stent, developed in
part through research at the Emory Heart Center, that has been shown
to greatly reduce restenosis (reclogging of arteries) following
Called “Cypher” stents and produced by the Cordis Corp.,
the stents release a drug called sirolimus as they prop open arteries;
they are the first U.S.-approved combination drug and stenting device
intended to help reduce restenosis of a treated coronary artery.
Angioplasty is the most common procedure in the United States to
treat potentially life-threatening coronary blockages. During angioplasty,
a balloon-tipped catheter is used to push aside atherosclerotic
plaques in arteries. Once the vessel has been widened, adequate
blood flow returns and stents (tiny mesh wire tubes) are frequently
used to keep arteries open.
However, restenosis has proven to be a frequent problem, and patients
who suffer from it may require additional medical procedures. For
many people, the new drug-eluting stents could offer a potential
solution to restenosis, which has been called the “Achilles
heel” of angioplasty.
The stents were tested in a study at the Emory Heart Center and
52 other U.S. medical centers. In the randomized, double-blind clinical
trial involving 1,058 patients, the Cypher stents were found to
greatly reduce restenosis compared to conventional stents.
“We believe these drug-eluting stents will be a major breakthrough
in defeating restenosis after stenting,” said John Douglas,
professor of cardiology and primary clinical investigator for the
In the trial, patients received either a plain metal stent or a
Cypher stent coated with sirolimus. “At eight-month angiographic
follow-up, patients treated with the Cypher stent had an overall
75 percent reduction in restenosis when compared to the control
group,” said Ziyad Ghazzal, associate professor of cardiology
and study co-investigator.
“In the particular subset of arteries tests, the success rate
of the drug-eluting stents was even more dramatic, with a success
rate of more than 90 percent over conventional, bare metal stents,”
said Douglas Morris, director of the Emory Heart Center. “We
are proud that Emory was one of the sites in the United States for
this extremely important multicenter study. I see the drug-eluting
stent as a major advance in the treatment of coronary artery disease.
It should lead to a profound reduction in restenosis, which is the
primary deterrent to the even more widespread applicability of coronary
The stent’s sirolimus coating does not kill cells but allows
the endothelium (the 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,”
said Douglas, who along with Emory colleagues implanted the country’s
first coronary artery stent at Emory Hospital in 1987. Today, three-fourths
of all patients undergoing angioplasties receive stents.
Without this cell covering, Douglas added, 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,”
he said. “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-eluting stent appears to be a
solution to this problem.”
“We hope the approval of the Cypher stents will expand the
horizon of percutaneous coronary interventions to include more patients
that we can help,” Ghazzal said.