Meta-analysis: Most DES Safer Than BMS, Biodegradability Offers No Extra Benefit

San Francisco, CA—Second-generation drug-eluting stents (DES) are generally safer than bare-metal stents (BMS) in regard to stent thrombosis, with everolimus-eluting stents offering the lowest risk, according to a meta-analysis.

 Si-Hyuck Kang, MD, of Seoul National University Hospital in South Korea, and colleagues examined 113 trials comprising 90,584 patients. Stents included in the study were BMS (9,844 patients), biodegradable-polymer biolimus-eluting (BP-BES; 6,589 patients), paclitaxel-eluting (PES; 15,399 patients), sirolimus-eluting (SES; 24,803 patients), zotorolimus-eluting Endeavor (ZES-E; 9,042 patients), zotorolimus-eluting Resolute (ZES-R; 3,809 patients), platinum-chromium everolimus-eluting (PtCr-EES; 3,271 patients) and cobalt-chromium everolimus-eluting (CoCr-EES; 17,827 patients).

The primary endpoint of definite or probable stent thrombosis within 1 year was available for 77 studies, comprising 75,484 patients. Compared with BMS, the BP-BES, SES, ZES-R, CoCr-EES and PtCr-EES stents were superior in terms of the primary outcome (Table 1). 

Table 1. Risk of Definite/Probable Stent Thrombosis

CoCr-EES and PtCr-EES were associated with a lower risk of definite or probable stent thrombosis than most of the other stents. Additionally, the CoCr-EES was the only stent with an improved safety profile over the BP-BES (OR 0.58; 95% CI 0.35-0.96).

Unexpected and interesting

According to Kang , there were several “unexpected and interesting findings” from the meta-analysis. “Biodegradable polymer DES was developed with an aim to reduce the risk for ST. In this study, ST risk of BP-BES was shown to be lower than BMS, but disappointingly higher when compared to CoCr-EES,” he added. 

Also notable, SES was superior within the first year but inferior to BMS after 1 year for definite or probable ST (OR 1.82; 95% CI 1.05-3.13). 

All of the DES models were associated with a reduced risk for repeat revascularization compared with BMS. TLR risk was lower with BP-BES, CoCr-EES and SES than with ZES-E and PES. All-cause and cardiac mortality were no different among any study stents; risk for MI within 1 year was lower with all DES except PES. The most significant improvement was with PtCr-EES (OR 0.42; 95% CI 0.22-0.75). All DES except BP-BES were superior to PES with regard to MI within 1 year, as well, with PtCr-EES again showing the most significant risk reduction (OR 0.49; 95% CI 0.27-0.87). 

The study suggests, according to the authors, that the optimal combination of stent alloy, geometry, strut thickness, polymer, and the drug employed play a more important role than the biodegradability of the polymer itself in determining safety.