The 38 mm Resolute drug-eluting stent met its performance goal with a one-year target lesion failure (TLF) rate of 5.4 percent for patients being treated for long coronary artery lesions, according to findings presented Oct. 23 at the 2012 Transcatheter Cardiovascular Therapeutics conference in Miami. The TLF rate among diabetic patients was similar.
“This is well below the performance goal [of 19 percent], meaning that this is a very efficacious stent,” said Shirish Hiremath, MD, director of the cardiac catheterization laboratory at Ruby Hall Clinic in Pune, India, and a researcher in the Resolute Asia study.
Core sizes of the Resolute Integrity stent (Medtronic) received FDA approval in February, but the 38 mm drug-eluting stent is still considered investigational in the U.S. Hiremath and colleagues conducted the analysis to demonstrate the safety and efficacy of the 38 mm device. An alternative for treating longer lesions—implantation using overlapping stents—has been associated with restenosis and stent thrombosis.
For this study the researchers combined data from two prospective nonrandomized clinical trials, Resolute U.S. and Resolute Asia, which together enrolled more than 1,700 patients. For this substudy, 223 patients (almost 38 percent with diabetes) with de novo coronary artery lesions of at least 35 mm were treated with 38 mm Resolute zotarolimus-eluting stents with a one-year follow-up. All received dual antiplatelet therapy for at least six months.
The primary endpoint was TLF at one year. The composite endpoints included clinically driven target lesion revascularization, cardiac death and target-vessel MI.
Lesion success, defined as attaining less than 50 percent residual stenosis of the target lesion using any percutaneous method, was 100 percent. Device success, the same criteria but using only the assigned device, was 97 percent. Procedure success, which was attaining less than 50 percent residual stenosis with no in-hospital major adverse cardiac events, was 96.3 percent.
Researchers reported that the one-year TLF rate was 5.4 percent and there were no late stent thrombosis events. Other clinical outcomes included target lesion revascularization, at 1.4 percent, and cardiac death, at 0.9 percent. Among diabetics, the TLF rate was 6 percent, target lesion revascularization rate was 2.4 percent and cardiac death rate was 1.2 percent.
The study population was predominantly male (78.9 percent of study group). Hiremath said that the findings should apply to women despite their lack of representation. “This could be a little biased but I don’t think in general this would be a big difference,” he said, because the stent’s performance is similar in both men and women.
“This is really a complex group,” Hiremath said. “When we use long stents we probably will be dealing with this kind of complexity.”
Medtronic, which supported the study, will submit the findings to the FDA.