Drug-Coated
Stents Help Diabetics with Heart Repair
Diabetic patients who received drug-eluting stents
had significantly less renarrowing of their treated arteries and fewer
serious cardiac problems than those treated with standard stents, which
do not release a drug, according to a report in the medical journal Circulation.
Stents are small mesh tubes that help keep arteries
open after angioplasty.
Drug-eluting stents are coated with medication to
prevent the formation of scar tissue inside the stent. These drug-eluting
stents release medication within the blood vessel itself. This medication
inhibits the overgrowth of tissue that can occur within the stent.
The effect of this medication is to deter the narrowing of the newly
stented blood vessel.
According to the study, diabetes afflicts more than
150 million people worldwide and is a major risk factor for heart disease
and stroke, which progresses faster in diabetic patients than in nondiabetics.
Among patients with diabetes, cardiovascular disease
is responsible for 75 percent of all hospital admissions and at least
80 percent of deaths, researchers say.
The finding is no great surprise, since a number
of studies in the US and other countries have shown the advantage of
drug-eluting stents.
But
the result is important because "overall, the
outcomes of diabetic patients after angioplasty are poorer than those
of nondiabetics," says study author Dr. Manel Sabate, a consultant
in cardiology at San Carlos University Hospital in Madrid.
The study included 160 people with diabetes, half
of whom had bare metal stents inserted after angioplasty. The other
half got stents coated with the drug sirolimus. Sirolimus prevents
further narrowing by inhibiting scar tissue formation.
In the nine months following the procedure, arteries
of patients given drug-coated stents narrowed by an average of only
0.06 millimeters, compared to 0.47 millimeters for the arteries of
those given bare-metal stents, the researchers report.
That difference had a very practical benefit.
While 29 of the 80 patients who got the bare metal
stents died or had adverse cardiac events such as heart attacks, only
eight of the 80 who got coated stents had such outcomes.
Only five of those who got coated stents needed
repeat angioplasty, compared to 25 of those getting the bare metal
stents.
During hospitalization, three standard-stent patients
suffered heart attacks, and one died of a cardiac rupture. There were
no major cardiac events in the drug-stent group.
"Conventional stent implantation still exhibits
a high incidence of major cardiac events in the diabetic population,
especially in those requiring insulin," Sabate said. "With the use
of conventional stents, the expected re-narrowing rate may vary from
30 percent to 60 percent in diabetic patients vs. 15 percent to 30
percent in nondiabetic patients."
The researchers said they will continue to monitor
the patients for the next two years to evaluate the long-term value
of drug-eluting stents.
Sirolimus, the drug used in the Spanish study, is
one of two medications available to coat stents.
Two European studies recently found an advantage
of sirolimus over the other drug, paclitaxel. The benefit in terms
of keeping arteries open, preventing heart attacks, and keeping patients
alive was greatest for people at highest risk - a group that includes
diabetics.
"It's an important study because it was specifically
designed to look at stents in patients with diabetes, rather than drawing
on a subgroup in a larger trial," says Dr. Sidney Smith, a professor
of medicine at the University of North Carolina and a spokesman for
the American Heart Association.
The
study is "good news for patients with diabetes," Dr.
Smith explains. "It shows that sirolimus-coated stents improve treatment
in both insulin-treated and noninsulin-treated diabetics."
The only flaw of the clinical trial was that it
began before the latest generation of stents became available, he notes.
"The trial did not compare the newer cobalt chromium
stents," Dr. Smith says. "It will be important to evaluate them."
Always consult your physician for more information.
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