Differential Clinical Outcomes After 1 Year Versus 5 Years in a Randomised Comparison of Zotarolimus-Eluting and Sirolimus-Eluting Coronary Stents (The SORT OUT III Study): A Multicentre, Open-Label, Randomised Superiority Trial

Study Questions:

What is the 5-year outcome of patients randomized to sirolimus-eluting stent (SES) compared with a zotarolimus-eluting stent (ZES)?


The authors reported the 5-year outcomes of patients enrolled in the SORT OUT III trial. SORT OUT III was a multicenter, open-label, randomized superiority trial performed at five percutaneous coronary intervention (PCI) centers in Denmark that randomized 2,332 patients undergoing PCI to a SES (Cypher Select Plus) or a ZES (Endeavor Sprint). The primary endpoint of the SORT OUT III study was a composite of major adverse cardiac events (MACE)—cardiac death, myocardial infarction, and target vessel revascularization—at 9-month follow-up. In the current study, endpoints included the occurrence of MACE and definite stent thrombosis at follow-up times of up to 5 years.


The study allocated 1,162 patients to receive the ZES and 1,170 to the SES arm. At 5-year follow-up, MACE rates were similar in patients treated with both types of stents (17% with ZES vs. 15.6% with SES; odds ratio [OR], 1.10; 95% confidence interval [CI], 0.88-1.37; p = 0.40). There was a significant difference in outcome at 1 year, where SES was superior (8% vs. 3.9%; OR, 2.13; 95% CI, 1.48-3.07; p < 0.0001), whereas between 1 and 5 years, there were more events in association with SES (9% vs. 11.6%; OR, 0.78; 95% CI, 0.59-1.02; p = 0.071). At 1-year follow-up, definite stent thrombosis was more frequent after implantation of the ZES (1.1% vs. 0.3%; p = 0.036), whereas the opposite finding was recorded between 1 and 5 years of follow-up (0.1% vs. 1.8%; OR, 0.05; 95% CI, 0.01-0.36; p = 0.003). In the ZES arm, 30% of the target lesion revascularizations occurred between 1 and 5 years of follow-up, whereas 77% of those in the SES group occurred during this period.


The investigators concluded that the superiority of SES compared with ZES at 1-year follow-up was lost after 5 years, and there was no difference in the outcome of the two stents at 5 years.


This study compared two stents, both of which have been supplanted in contemporary clinical practice by second-generation drug-eluting stents. The study, however, is important for many reasons. First, the incidence of very late stent thrombosis is markedly different between the two stents. While uncommon, the complication appears to more commonly be associated with the SES compared with ZES, suggesting that this may not be a class effect. Second, the trial highlights the need for longer-term follow-up in evaluations of newer coronary stents. Finally, the event rates in this trial were much higher than those seen in the initial trials with both of the stents, and invoke the need for clinical trials with inclusion of a broader patient population.

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