ORLANDO — The largest comparison to date of the three drug-eluting coronary stents on the U.S. market showed that the sirolimus-eluting stent was significantly more effective and at least as safe as were the other two models, on the basis of results from a Korean study with more than 2,600 patients.
The most notable difference among the sirolimus-, zotarolimus-, and paclitaxel-eluting coronary stents compared in the study was the 12-month rate of ischemia-driven target-lesion revascularization (TLR), which occurred at a rate of 1.4% in 878 patients who received one or more sirolimus-eluting coronary stents (SES), Dr. Seung-Jung Park said at the annual meeting of the American College of Cardiology.
This rate was significantly below the 4.9% TLR rate among the 883 patients who received the zotarolimus-eluting stents (ZES), and significantly less than the 7.6% rate among the 884 patients who received paclitaxel-eluting stents (PES).
Despite the clear efficacy advantage of SES in this study, “the definitive answer” regarding the relative long-term safety of the three stent types will not be available until results are reported from a controlled study now underway with more than three times as many patients, said Dr. Stephan Windecker, head of interventional cardiology at the Swiss Cardiovascular Center in Bern.
Dr. Windecker summarized the findings of three studies, including the new report, that compared ZES and SES, and concluded that SES were “more effective with a similar safety profile as ZES.”
He also summarized findings from two studies, including the new report, that compared ZES and PES and concluded that ZES “were at least as effective with a better safety profile than PES.”
The better safety profile of ZES compared with PES was based on the rate of MIs in a combined analysis of the ZEST results and findings from the ENDEAVOR IV study, which compared ZES and PES in about 1,500 patients. The combined results showed that ZES reduced the rate of MIs by 30% compared with the rate in PES recipients, a statistically significant difference, said Dr. Windecker.
He disclosed that he has received consulting fees from Cordis Corp., a Johnson & Johnson company that markets the SES (Cypher); from Boston Scientific, the company that markets the PES (Taxus Liberte); and from Medtronic, the company that markets the ZES (Endeavor).
The Zotarolimus-Eluting Stent Versus Sirolimus-Eluting Stent and Paclitaxel-Eluting Stent for Coronary Lesions (ZEST) trial was done at 19 centers in South Korea. It enrolled unselected patients who required coronary stenting to treat silent ischemia, stable angina, unstable angina, or non-ST-elevation myocardial infarction. The study excluded patients with ST-elevation MI, left main disease, in-stent restenosis, severe left ventricular dysfunction, or cardiogenic shock.
The study was sponsored in part by Medtronic. Dr. Park said that he and all of his associates had no other financial relationships to disclose.
The average patient age was 62, and two-thirds were men. A quarter of the patients had diabetes. The most common indication for stenting was unstable angina, in 47%, followed by stable angina, in 39%. An average of 1.6 stents were placed in each patient. The total lesion length stented was more than 20 mm in 55% of patients, and 10–20 mm in 40%.
The study's primary end point was the combined rate after 12 months of death from any cause, MI, and ischemia-driven target-vessel revascularization. The combined rate was 8.3% in the SES patients, 10.1% in the ZES patients, and 14.2% in those treated with PES, reported Dr. Park, director of interventional cardiology at the Asian Medical Center in Seoul, South Korea. The difference in rates between the ZES and PES patients was statistically significant; the difference between the ZES and SES groups was not significant.
The significant efficacy differences among the three groups was confined to differences in the rates of target-vessel revascularization and TLR. The rates of death and MI were similar in the three groups.
The rate of definite or probable stent thrombosis was significantly lower in the SES group, with no stent thrombosis at all, compared with the ZES patients (a 0.7% rate) and the PES patients (0.8%). The overall low rate of stent thromboses makes the risk estimates “imprecise,” Dr. Windecker said.