WASHINGTON, D.C.—Resolute Integrity drug-eluting stents showed very strong results in delivery success and inhospital patient outcomes, based on the results of the large-scale, real-world DELIVER study, presented Feb. 24 at the 2013 Cardiovascular Research Technologies (CRT) annual meeting.
As a prospective, multicenter, single-arm, open-label registry, the DELIVER (DELIverability of the Resolute Integrity stent in all-comer Vessels and cross-ovER stenting) study assessed the Resolute Integrity zotarolimus-eluting stent (Medtronic) in a real-world population of 7,740 patients with 10,449 lesions.
Principal investigator Jochen Wohrle, MD, of the department of internal medicine at the University of Ulm in Ulm, Germany, explained during his presentation of the study that there were no limitations on lesions, vessel location or morphology. There were two groups in the study: Resolute was used as the primary stent in the first group and after the failure of another stent in the second group, which was classified as the crossover group.
The Resolute Integrity has a BioLinx polymer that is designed to allow for extended delivery of the zotarolimus drug to the tissue, with 85 percent of the drug eluted by 60 days and the rest by 180 days. The stent platform has a MicroTrac Delivery system with continuous sinusoid technology.
The primary endpoint for the study was delivery success, defined as complete passage of the Resolute Integrity stent across the target lesion with full expansion of the stent to the desired diameter at the desired location. The researchers assessed a timeframe from stent implantation to hospital discharge (average one to three days). Major adverse cardiac events (MACE) were defined as inhospital cardiac death, MI, emergent CABG or repeat PCI.
Of the 7,740 patients, Wohrle said there was a “high rate” of diabetes mellitus, at 35 percent. Also, 30 percent of patients had unstable angina and 30 percent experienced an acute MI.
He classified the delivery success as “very high,” at 98.9 percent when the Resolute was used as the primary stent; 10,733 stents were used in this group. The delivery success rate was 98 percent in the crossover group, which was a much smaller group, with 49 stents used.
The inhospital clinical outcomes (2.5 days average stay) were “also quite good,” Wohrle said. The definite stent thrombosis rate was 0.1 percent and the probable stent thrombosis rate was 0.1 percent. The overall MACE rate was 1.6 percent.
There were different baseline lesion characteristics between the radial and the femoral groups. “There were more complex lesion characteristics in the femoral group, like multivessel PCI, bifurcated lesions; however, the inhospital clinical outcomes were pretty similar,” reported Wohrle. The radial approach was used in 46 percent of the population.
“The delivery success was high when Resolute was used as the first choice of stent as well as when it was used as a crossover stent,” he concluded.
Study panelist Michel Joner, MD, of Deutsches Herzzentrum München in Munich, said the results were “compelling,” and questioned whether the positive findings resulted from the new type of polymer.
Wohrle said that it wasn’t clear whether it the polymer alone or the delivery platform resulted in the positive results. He added that the study had concluded, but they may investigate certain subgroups.
Medtronic funded the study.