Meta-analysis: Cobalt-Chromium EES Take the Lead Over BMS, Other DES in STEMI

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In patients with ST-segment elevation myocardial infarction (STEMI), cobalt-chromium everolimus-eluting stents (EES) result in less death and myocardial infarction (MI) as well as less stent thrombosis than bare-metal stents (BMS), according to results from a study scheduled to be published online June 4, 2013, ahead of print in the Journal of the American College of Cardiology.

Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), and colleagues conducted a network meta-analysis of 22 trials that randomized a total of 12,453 STEMI patients to BMS or first- or second-generation DES, all of which are currently FDA approved:

  • Cypher sirolimus-eluting stents (SES; Cordis, Miami Lakes, FL)
  • Taxus Express and Liberté paclitaxel-eluting stents (PES; Boston Scientific, Natick, MA)
  • Cobalt-chromium EES, marketed as Xience (EES; Abbott Vascular, Santa Clara, CA)
  • Endeavor phosphorylcholine-based zotarolimus-eluting stents (PC-ZES; Medtronic, Santa Rosa, CA)

At 1-year follow-up, risks of total or cardiac mortality were similar among the different stent types. However, cobalt-chromium EES were associated with lower risks of death/MI, cardiac death/MI, definite stent thrombosis, and definite/probable stent thrombosis compared with BMS (table 1).

Table 1. One-Year Follow-up: OR (95% CI)

 

Death/MI

Cardiac Death/MI

Definite ST

Definite/
Probable ST

CoCr EES
vs. BMS

0.65 (0.46-0.90)

0.63 (0.42-0.92)

0.32 (0.11-0.78)

0.36 (0.18-0.66)


Among the other DES, only SES were associated with lower rates of cardiac death/MI compared with BMS (OR 0.70; 95% CI 0.49-0.98).

The reductions in cardiac death/MI and in definite/probable stent thrombosis with cobalt-chromium EES were already apparent at 30 days, and the benefits were maintained out to 2-year follow-up (OR 0.70; 95% CI 0.50-0.96 and OR 0.41; 95% CI 0.16-0.88, respectively).

Probability modeling indicated that compared with BMS and the other DES, cobalt-chromium-EES had a:

  • 59% odds of having the lowest rate of cardiac death/MI
  • 56% odds of having the lowest rate of MI
  • 63% odds of having the lowest rate of definite ST

SES, meanwhile, had an 82% probability of having the lowest rates of TVR.

Extends Prior Analyses to STEMI

The study authors note that their research was fueled in part by data showing an ongoing propensity for very late stent thrombosis with first-generation SES and PES. “This concern,” they add, “is particularly relevant for patients with STEMI, who compared to patients with stable coronary artery disease have greater rates of [stent thrombosis] due to heightened platelet activation and the presence of thrombus.”

According to Dr. Stone and colleagues, the current analysis extends prior findings, including those of 2 network meta-analyses that did not differentiate patients with STEMI or report cardiac mortality data. The reduced rates of stent thrombosis with cobalt-chromium-EES vs. BMS in the current study “further suggest reductions with [cobalt-chromium]-EES in the ‘hard’ endpoints of cardiac death/MI and MI,” they note.

They also say the data “demonstrate that it is inappropriate to consider SES and PES as one category of DES, because significant differences in clinical outcomes are apparent between these 2 devices.”

Notably, SES reduced cardiac death/MI compared with BMS while PES did not, and they imparted the greatest reduction in TVR. SES also showed a trend toward reduced definite stent thrombosis at 1 year (OR 0.58; 95% CI 0.28-1.08) that was absent with PES (OR 0.96; 95% CI 0.56-1.67).

However, the investigators add that different durations of dual antiplatelet therapy among the studies is a possible confounding factor and that “network meta-analysis assume that patients enrolled in the studies could have been sampled from the same theoretical population, and that similar comparators between different trials have a consistent risk-benefit ratio.”

Another factor to consider, they write, is that follow-up data for cobalt-chromium-EES are limited to 2 years, “and therefore whether the observed differences would remain constant, increase or diminish with more extended follow-up is unknown.” A network meta-analysis of this type also is not powered to detect differences in clinical outcomes between the various DES and BMS beyond 1 year, they add.

Note: Dr. Stone and several co-authors are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 


Source:
Palmerini T, Biondi-Zoccai G, Della Riva D, et al. Clinical outcomes with drug-eluting and bare metal stents in patients with ST-segment elevation myocardial infarction: Evidence from a comprehensive network meta-analysis. J Am Coll Cardiol. 2013;Epub ahead of print.

 

 

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Disclosures
  • Dr. Stone reports serving as a consultant for Abbott Vascular, Boston Scientific, and Medtronic.

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