SCAAR Confirms Low Very Late Stent Thrombosis Risk with Newer DES

BARCELONA, Spain—Newer drug-eluting stents (DES) carry a very late stent thrombosis risk similar to that of bare-metal stents and lower than that of older DES, according to results of a large registry study presented on August 30, 2014, at the European Society of Cardiology Congress.

“We can be reassured that the new-generation drug-eluting stents are safe when it comes to stent thrombosis,” said Christoph Varenhorst, MD, PhD, of Uppsala Clinical Research Center (Uppsala, Sweden).  

In multivariate analyses performed per stent (not per patient), the risk of definite stent thrombosis up to 1 year after implantation was lower for both older and newer DES compared with BMS. Past 1 year, however, older DES carried a higher risk and newer DES a similar risk compared with BMS (table 1). 

Table 1. Stent Thrombosis Risks of DES vs BMS

“After 1 year, the possible confounding effect of different dual antiplatelet treatment strategies, different indications for the procedure, and procedural success is likely smaller,” Dr. Varenhorst noted.

In an analysis focused on the various antiproliferative agents—sirolimus, paclitaxel, everolimus, zotarolimus, and biolimus—used on the stents, the risk of definite stent thrombosis during the first year after implantation was consistently lower, with RRs ranging from 0.33 with biolimus to 0.78 with paclitaxel vs BMS. 

After 1 year, the risk was greater with sirolimus (RR 2.00; 95% CI 1.41-2.83) and paclitaxel (RR 1.54; 95% CI 1.14-2.08).

Results Affirm Safety of Newer DES 

One of the co-chairs of the session at which Dr. Varenhorst presented the findings, Marco Roffi, MD, of University Hospital of Geneva (Geneva, Switzerland) said “these are very reassuring data for interventional cardiologists and for patients.”

Asked by Dr. Roffi whether the analyses accounted for the use of newer, more potent P2Y12 inhibitors, Dr. Varenhorst said that adjustment was made for the type of agent used. He pointed out, however, that use of dual antiplatelet therapy for longer than a year is not recommended in Sweden, “so the impact of different dual antiplatelet therapy treatment strategies after 1 year is probably none or small.” 

Panelist Marco Valgimigli, MD, PhD, of Erasmus Medical Center (Rotterdam, The Netherlands), also said that the results were reassuring, but questioned why the Endeavor stent was included in the older-generation DES group when previous studies have classified it as a newer-generation device.

Dr. Varenhorst acknowledged that the groupings are arbitrary, as there is not a consensus about what makes DES part of the older or newer generations. He additionally pointed out that the study was limited by the possibility of bias from unknown confounders. 

“Nonetheless,” he said, “the reliability of our results [is] strengthened by complete angiographic long-term follow-up, registry source data verification, and the use of definite, angiographically proven stent thrombosis as our only endpoint measure.”

Source:
Varenhorst C, Sarno G, Olivecrona G, et al. SCAAR: lower late and very late stent thrombosis rates with new-generation drug-eluting stents compared to bare metal stents. Presented at: European Society of Cardiology Congress; August 30, 2014; Barcelona, Spain.

Disclosures:

• Dr. Varenhorst reports receiving an institutional grant from AstraZeneca and honoraria/consultant/lecture fees from AstraZeneca and The Medicines Company.
   

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