Meta-Analyses Show Improved Outcomes with DES vs. BMS

MIAMI BEACH, FLA.—A number of recent meta-analyses have begun to shed light on some critical questions with regard to DES, according to two presentations during the DES Summit on Monday. One pooled study showed improved rates of late stent thrombosis with cobalt-chromium everolimus-eluting stents, and another found excellent clinical outcome results with second-generation DES while highlighting some differences in safety and efficacy between various device types.

Sripal Bangalore, MD, of New York University School of Medicine, said that recent studies have tended to compare one DES against a comparator encompassing all other DES types, making relative efficacy and safety comparisons of each stent difficult. In a meta-analysis attempting to hierarchically evaluate those relative differences, Bangalore and colleagues analyzed 76 randomized controlled trials with over 117,000 patient-years of follow-up; the studies compared DES against each other or against BMS, and all had a follow-up of at least 6 months and included at least 100 patients.

All the DES included – sirolimus(SES)-, paclitaxel (PES)-, everolimus(EES)-, zotarolimus (ZES)- and zotarolimus-eluting Resolute stents (ZES-R) – resulted in a decreased risk of target vessel revascularization  (TVR) compared with BMS (see Figure). The analysis also showed that EES had the highest probability of yielding the lowest TVR rate, at 42.07%, followed by SES (35.22%) and ZES-R (22.7%).

Results were very similar for TLR outcomes, with the greatest risk reductions with SES (RR 0.32; 95% CI, 0.27-0.38); EES (RR 0.28; 95% CI, 0.22-0.38); and ZES-R (RR 0.39; 95% CI, 0.23-0.66).

There were no significant differences between DES and BMS with regard to mortality, nor when any of the DES were used as the reference stent. ZES-R, however, had by far the highest probability of yielding the lowest death rate (68.48%); this was followed by EES (17.17%) and PES (8.87%). EES had the highest probability of yielding the lowest MI rate (46.9%), followed by ZES (26.66%) and ZES-R (26.36%).

Improved stent thrombosis rates

Dr. Bangalore’s study also found that EES had the highest probability of the lowest stent thrombosis rate, at 86.32%. This result was supported by another meta-analysis presented by Tullio Palmerini, MD, of the Policlinico S. Orsola in Bologna, Italy. The analysis included 49 randomized clinical trials and 50,844 patients, and used methods that allowed for indirect comparisons of stents that may not have been compared directly in any given trial. Cobalt-chromium EES showed a significantly lower of definite stent thrombosis rate vs. BMS at 30 days (OR 0.21; 95% CI 0.11-0.42), as well as at 1 year (OR 0.23; 95% CI 0.13-0.41) and at 2 years (OR 0.35; 95% CI 0.17-0.69).

The cobalt-chromium EES also yielded significantly lower risk for definite stent thrombosis at 30 days and at 1 year when compared with PES, SES, ZES, and ZES-R; at 2 years, it was significantly better than PES. Other comparisons were not presented.

“Deriving from a meta-analysis, these findings should be considered, of course, hypothesis-generating,” Dr. Palmerini said. “However, large sample size, lack of heterogeneity, and the consistency between direct and indirect estimates in the network meta-analysis give strong support to these findings.”

In conclusion, Dr. Bangalore also said that more data are required, particularly on the Resolute stent, but that the meta-analyses do show that all currently available DES compare well to BMS. “Among the DES types, there were considerable differences, such that the Resolute stents were most efficacious, and EES were the safest stents,” he said. “DES should be the benchmark for both efficacy and for safety.”