New Drug-Eluting Stents Far Safer Than Older Models



Percutaneous coronary intervention with new-generation drug-eluting stents is associated with significantly lower risk of restenosis, stent thrombosis, and death, compared with both older generation drug-eluting stents and bare-metal stents, according to findings from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR).

The findings bolster the current recommendations regarding use of drug-eluting stents (DES), and are the first to show a mortality benefit with new- vs. older-generation DES. Compared with older bare-metal stents (BMS), the risk of death was reduced with older DES at 2 years, by 28%, and lower still with new DES, by 45%.

The 1- and 2-year restenosis rates among 10,551 implantations with a new-generation DES in SCAAR were 2.8% and 3.9%, respectively, compared with 4.0% and 5.8% in 19,202 implantations with an older-generation DES (cumulative adjusted hazard ratio, 0.62), and 6.3% and 7.4% in 64,631 implantations with a BMS (cumulative adjusted HR, 0.29), wrote Dr. Giovanna Sarno of Uppsala (Sweden) University and colleagues. The results are online in the Jan. 9 issue of the European Heart Journal.

The 1- and 2-year definite stent thrombosis rates among the new-generation DES implantations were 0.5% and 0.6%, respectively, compared with 0.9% and 1.3% in the older-generation DES implantations, for a risk reduction of 43%, and 1.2% and 1.4% in the bare-metal stent implantations, showing a 62% reduction in risk.

The overall mortality rate among the 61,351 patients who underwent the 94,384 stent implantations was 5.6%. Mortality was 1.9% in the new-generation DES recipients, compared with 3.4% in the older-generation DES recipients (adjusted hazard ratio, 0.77), and 6.8% in the bare-metal stent recipients (adjusted HR 0.55), the investigators said (Eur. Heart J. 2011 Jan. 9 [doi:10.1093/eurheartj/ehr479]).

"A main finding of this study is that new-generation DES are associated with a 38% lower risk of clinically relevant restenosis and a 43% lower risk of definite stent thrombosis up to 2 years, compared with older-generation DES in a large real world population," the investigators said.

Furthermore, the findings indicate that mortality with new-generation and older-generation DES is 45% and 28% lower, respectively, than with bare-metal stents, and 23% lower with new-generation DES than with older-generation DES, they said.

New-generation DES were developed with an improved design, including thinner struts and more biocompatible polymers, thought to have potential for overcoming limitations – namely those relating to long-term safety, and particularly risk of late stent thrombosis – of older generation DES. Although randomized studies demonstrated low late loss and thrombotic risk with restricted use of the new generation DES, only a few trials and reports from single-center experiences evaluating only one type of the new generation DES have looked at unrestricted use.

"Our study evaluated the performance up to 2 years of different types of new-generation DES in an unselected large real-world population – including patients with myocardial infarction, three-vessel and/or left main disease, bifurcation lesions, graft disease, restenotic lesions, and chronic total occlusions," the investigators said.

Participants in the observational cohort study included all patients in Sweden who received coronary stents from November 2006 to October 2010. In their analysis, the investigators adjusted for potential confounders, including age, sex, diabetes, hypertension, dyslipidemia, smoking status, clinical indication of the procedure, medications used at the index procedure, treated vessel and lesion type, and previous MI and revascularization.

In a press statement, study author Dr. Stefan James, also of Uppsala University, described the findings as "intriguing" and noted that, "the low rates of restenosis and stent thrombosis correspond with the results of several recent randomized trials, and this may well translate into mortality reduction in a sufficiently large study population."

However, despite the large sample size, the findings of this study should be considered within the context of the intrinsic limitations of registry data. Although the findings may be useful for the management of patients at risk for stent thrombosis and restenosis – and although they support the current strong recommendations for the use of drug-eluting stents in appropriate patients, they require confirmation by large-scale randomized studies, the investigators concluded.

New-generation DES used in this study included Endeavor Resolute (Medtronic Inc.), XienceV, Xience Prime (Abbott Laboratories), and Promus and Promus Element (Boston Scientific Corp.). Older generation DES included Cypher and Cypher Select (Cordis Corp., Miami), Taxus Express and Taxus Liberté (Boston Scientific Corp.), and Endeavor (Medtronic Inc.) Bare-metal stents include Multilink, Multilink MiniVision, and Flexmaster (Abbott Laboratories), Driver and Micro Driver coronary (Medtronic Inc.), Liberté (Boston Scientific Corp.), Braun Coroflex Blue (B.Braun Melsungen AG, Germany), and Chrono stent (CID, Saluggia, Italy).

SCAAR is sponsored by the Swedish Health Authorities. Financial support for analyses was provided by the Swedish Heart and Lung Foundation. One study author, Dr. James, disclosed that he received institutional research grants from Terumo, Medtronic, and Vascular Solutions.

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