drug-eleuting stents: short-term success and long-term complications
outrider
I
Coronary Artery Stents That Release Medication Appear More Effective
than Traditional Stents For Patients With Heart Attack
II
Drug-Releasing Stents Showing Higher Complication Rate Than Clinical
Trials Indicated
III
Editorial: Drug-Eluting Stents in Acute Myocardial Infarction
CHICAGO - A type of coronary artery stent that releases a medication
appears to result in better outcomes than traditional stents for heart
attack patients, according to a study in the May 4 issue of JAMA.
Sirolimus, a substance that is thought to help prevent reclosure of
coronary arteries, can be released from certain types of stents (metal
devices inserted to keep a coronary artery open after angioplasty) to
greatly reduce the need for target-vessel revascularization (TVR)
compared with bare-metal stents (i.e., stents without medication),
according to background information in the article. These drug-eluting
stents have the potential to further improve long-term clinical outcome
after primary percutaneous coronary intervention (PCI), such as
angioplasty. However, the lack of randomized trials to assess the
safety and long-term efficacy of sirolimus-eluting stent implantation
in patients with acute ST-segment elevation (a certain measurement on
an electrocardiogram) myocardial infarction (STEMI), in conjunction
with the expected financial consequences, currently limit use of
sirolimus-eluting stents in this setting. Current clinical guidelines
specifically recommend the drug abciximab during primary PCI. At
current European list prices, the use of the drug tirofiban instead of
abciximab would absorb the difference in cost between stenting with
sirolimus-eluting vs. bare-metal stents.
Marco Valgimigli, M.D., of the University of Ferrara, Italy and
colleagues compared angiographic and clinical outcomes for the
treatments of high-dose tirofiban plus sirolimus-eluting stenting vs. a
current preferred strategy for STEMI treatment, pretreatment with
abciximab plus bare-metal stenting. The STRATEGY trial included 175
patients presenting to a single referral center in Italy with STEMI or
presumed new left bundle-branch block between March 6, 2003 and April
23, 2004. Patients received either tirofiban regimen plus
sirolimus-eluting stenting (n = 87) or abciximab plus bare-metal
stenting (n = 88).
The researchers found that 14 of 74 patients (19 percent) in the
tirofiban plus sirolimus-eluting stent group and 37 of 74 patients (50
percent) in the abciximab plus bare-metal stent group reached the
primary end point (death, nonfatal heart attack, stroke, or binary
restenosis [narrowing of artery] at 8 months). The cumulative incidence
of death, reinfarction, stroke, or TVR was significantly lower in the
tirofiban plus sirolimus-eluting stent group (18 percent) vs. the
abciximab plus bare-metal stent group (32 percent), predominantly
reflecting a reduction in the need for TVR. Binary restenosis was
present in 6 of 67 (9 percent) and 24 of 66 (36 percent) patients in
the tirofiban plus sirolimus-eluting stent and abciximab plus
bare-metal stent groups, respectively.
"In conclusion, our study provides proof of concept for a new treatment
strategy in STEMI that incorporates unrestricted use of
sirolimus-eluting stenting but results in no (European market) or only
a modest (U.S. market) increase in medical expenditure," the authors
write.
(JAMA. 2005;293:2109-2117.}
Drug-Releasing Stents Showing Higher Complication Rate Than Clinical
Trials Indicated
In a related report in this week's JAMA, "real-world" use of
drug-releasing coronary artery stents reveals higher rates of stent
thrombosis (narrowing due to blood clots) 9 months after stent
implantation than were indicated in clinical trials.
Physicians are now using drug-eluting stents for a wide variety of
clinical and anatomic situations, many of which have not been evaluated
in randomized studies, according to background information in the
article. Data have been limited regarding the risks of thrombosis
(blood clots) beyond 30 days outside of clinical trials.
Ioannis Iakovou, M.D., of the Centro Cuore Columbus and San Raffaele
Hospital, Milan, Italy and colleagues analyzed the incidence,
predictors, and clinical outcome of stent thrombosis at 9-month
follow-up in an observational study.
The study was conducted at 3 hospitals in Germany and Italy. A total of
2,229 patients underwent successful implantation of sirolimus-eluting
(1,062 patients, 2,272 stents) or the drug paclitaxel-eluting (1,167
patients, 2,223 stents) stents between April 2002 and January 2004.
At 9-month follow-up, 29 patients (1.3 percent) had stent thrombosis (9
[0.8 percent] with sirolimus and 20 [1.7 percent] with paclitaxel,
substantially higher than rates reported in major clinical trials (0.4
percent at 1 year for sirolimus and 0.6 percent at 9 months for
paclitaxel). Among these 29 patients, 13 died (case fatality rate, 45
percent) and the majority of others experienced nonfatal heart attack).
Independent predictors of stent thrombosis included premature
antiplatelet therapy discontinuation (thrombosis occurred in 29 percent
of these patients), kidney failure, and diabetes (27 percent of the
patients had diabetes).
(JAMA. 2005;293:2126-2130.}
Editorial: Drug-Eluting Stents in Acute Myocardial Infarction
In an accompanying editorial, Mauricio G. Cohen, M.D., and E. Magnus
Ohman, M.D., of the University of North Carolina, Chapel Hill, discuss
the findings of the STRATEGY trial.
"...the STRATEGY trial is an important step in exploring the use of
drug-eluting stents in the setting of AMI. The data suggesting that the
use of drug-eluting stents in AMI may be superior to the traditional
bare-metal stent approach are encouraging. However, the focus should
now shift to the long-term prevention of thrombotic complications
through appropriate long-term antiplatelet therapies. It is remarkable
to see how STEMI management has evolved over the last decade. With use
of increasingly sophisticated stent technology, patients with STEMI are
now enjoying substantial benefit by virtue of improved reperfusion with
primary PCI, fewer ischemic complications, and lower rates of long-term
restenosis. A goal that seemed very distant only a decade ago appears
now to have been achieved," the authors write.
(JAMA. 2005;293:2154-2156.}