EES Show Long-term Safety Advantage over SES

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Coronary artery disease patients who receive everolimus-eluting stents (EES) are less likely to experience myocardial infarction (MI) or need repeat revascularization over the next few years than those implanted with sirolimus-eluting stents (SES), according to observational data published in the May 24, 2011, issue of the Journal of the American College of Cardiology. The study suggests that the reduced MI rate is driven in part by a lower risk of stent thrombosis.

For the study, Stephan Windecker, MD, of Bern University Hospital (Bern, Switzerland), and colleagues compared the outcomes of the unrestricted use of EES (Xience V, Abbott Vascular, Santa Clara, CA, and Promus, Boston Scientific, Natick, MA) and SES (Cypher, Cordis, Miami Lakes, FL) in 1,342 propensity score-matched pairs of patients for up to 3 years. Patients who received SES were treated between May 2004 and January 2006, whereas patients who received EES were treated between November 2006 and March 2009.

Lower Rates of MI, TVR with EES

Overall, use of EES was associated with a trend toward a lower risk of the primary endpoint, a composite of death, MI, and TVR, compared with SES. The trend was driven by significantly lower rates of MI and TVR. Rates of all-cause and cardiac mortality were similar, whereas Q-wave MI and the composite of cardiac death or MI were less frequent with EES (table 1).

Table 1. Outcomes up to 3 Years

A sensitivity analysis of the primary outcome adjusted for procedural characteristics yielded similar results (HR 0.78; 95% CI 0.63-0.97; P = 0.029).

Importantly, rates of Academic Research Consortium-defined definite stent thrombosis and definite or probable stent thrombosis were lower with EES than SES (table 2).

Table 2. Stent Thrombosis up to 3 Years

 
In addition, clinical outcomes associated with definite stent thrombosis, including MI (HR 0.25; 95% CI 0.08-0.75; P = 0.013) and TVR (HR 0.33; 95% CI 0.12- 0.92; P = 0.033), were less frequent with EES. The differences were less pronounced, however, for MI and TVR occurring in the absence of stent thrombosis. The authors say this suggests “that differences in revascularization in favor of EES were related in part to a lower predisposition for [stent thrombosis] rather than restenosis.”

The authors also note that data comparing EES with SES are limited and say their long-term data “provide novel evidence that [stent thrombosis] beyond 1 year is less frequent with EES compared with SES (P = 0.007), circumventing an important shortcoming of early generation DES.”

While the mechanisms underlying the lower risk of stent thrombosis are unknown, they suggest that it could be related to:

• Lower strut thickness with less arterial injury and more rapid and complete endothelialization
• A biocompatible polymer less prone to hypersensitivity reactions
• Lower dose of the antiproliferative drug

Larger Studies Needed to Confirm EES Advantage

Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), told TCTMD in an e-mail communication that the study, although not randomized, suggests that EES have significant safety advantages over SES.

“The reduction in stent thrombosis was evident in the early, late, and very late periods after stenting, and is consistent with the findings from 4 randomized trials of SES vs. EES,” Dr. Stone wrote. “Larger studies will need to be done to determine whether EES have greater or similar antirestenotic efficacy than SES, and whether there is any difference in late restenosis catchup independent of late stent thrombosis.”

He added that the studies taken together also suggest that patients treated with SES may benefit from longer dual antiplatelet therapy, while such therapy may be able to be abbreviated in those implanted with EES, although randomized trials are necessary to confirm that strategy.

Study Details

All patients received a loading dose of 300 to 600 mg clopidogrel during the procedure and were prescribed aspirin once daily for life and clopidogrel for 12 months. Use of glycoprotein IIb/IIIa antagonists was left to the discretion of the operator.

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Source:
Räber L, Jüni P, Nüesch E, et al. Long-term comparison of everolimus-eluting and sirolimus-eluting stents for coronary revascularization. J Am Coll Cardiol. 2011;57:2143-2151.

 

• Dr. Windecker reports receiving consulting and lecture fees from Abbott, Boston Scientific, Biosensors, Cordis, and Medtronic.
• Dr. Stone reports serving as a consultant to Abbott Vascular, Boston Scientific, Bristol-Myers Squibb/Sanofi-Aventis, Eli Lilly, Medtronic, and Merck.

 

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