Newswise — 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. Available post-embargo at http://JAMA.com)
Editor's Note: For funding/support and financial disclosure information, please see the JAMA article.
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. Available post-embargo at http://JAMA.com)
Editorial: Drug-Eluting Stents in Acute Myocardial InfarctionIn 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. Available post-embargo at http://JAMA.com)
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