ACC: Everolimus-eluting stent may show PLATINUM results
Xience V drug-eluting stent
Image source: Abbott Vascular
NEW ORLEANS--Outcomes of a platinum chromium everolimus-eluting stent were non-inferior to the cobalt chromium everolimus-eluting stent and both showed similar rates of cardiac death, MI and ischemia-drive target lesion revascularization, according to the results of the PLATINUM trial presented yesterday at the 60th annual meeting of the American College of Cardiology.

While recent data has proven that the cobalt chromium everolimus-eluting stent (CoCr-EES; Xience V / Promus) is safe and produces low rates of restenosis and stent thrombosis, a novel platinum chromium everolimus-eluting stent (PtCr-EES; Promus Element) may prove safe and effective due to its modified scaffold design that improves durability.

And because the FDA looks for data comparing the outcomes, safety and effectiveness of devices and/or procedures during the approval process, Gregg W. Stone, MD, director of cardiovascular research at the New York-Presbyterian Hospital/Columbia Medical Center in New York City, and the study’s principal investigator, said the researchers set out compare outcomes data of these two devices.

Stone et al enrolled 1,530 patients at a 1:1 ratio to receive either a cobalt chromium everolimus-eluting stent (n=762) or platinum chromium everolimus-eluting stent (n=768) during the prospective, randomized PLATINUM (A Prospective, Randomized Investigation of a Novel Platinum Chromium Everolimus-Eluting Coronary Stent) trial.

Patients had one or two de novo native coronary artery target lesions and the primary endpoint used was target lesion failure at 12 months related to cardiac death or MI related to the target vessel or ischemia-driven target lesion revascularization (TLR).

Stone reported that the technical success was 98.8 percent for CoCr-EES compared with 99.4 percent for the PtCr-EES. These numbers for clinical procedural success were 98.2 percent and 98.3 percent, respectively, and unplanned bail-out stenting occurred at a rate of 9.8 percent for patients receiving a CoCr-EES and 5.9 percent for those with a PtCr-EES.

The composite endpoint occurred at a rate of 3.4 percent in the PtCr-EES arm and 2.9 percent in the CoCr-EES arm.

Stone reported that the study had extremely low event rates that equated to 3.3 percent TLF overall at one-year. “Approximately 3.3 percent of patients have an adverse event at one year--one out of 33 patients—and 32 out of 33 patients had nothing happen at the end of one year which is quite extraordinary.”

Additionally, Stone et al found that that rates of TLR were about 1.9 percent in each arm, which equated one out of 50 patients requiring repeat revascularization procedure at the end of one year for both arms. What Stone called the “lowest numbers we have seen.”

Incidence of target vessel revascularization occurred at a rate of 2.9 percent for the CoCr-EES arm compared with 2.7 percent in the PtCr-EES arm, and the rates of all-cause death and MI did not statistically differ between the two groups.

“The trial was not designed to assess differences in deliverability, acute performance or ease of use,” said Stone. “That will be uncovered after hundreds of thousands of investigators use these devices in tens of thousands of patients to see if there really are practical differences in the cath lab.”

“A novel platinum chromium everolimus stent has been developed which has been shown to be noninferior to the predicate cobalt chromium everolimus-eluting stent, with non-significant differences in measures of safety and efficacy demonstrated through 12-month follow-up after PCI,” concluded Stone

“Adding this [platinum stent] to the mix, the bar is really high right now and the question is, is this a step forward?” asked panelist, Charles J. Davidson, MD, from the Northwestern Memorial Hospital in Chicago.

“It really seems that there has been tremendous progress made and the MACE rates, stent thrombosis rates and target lesion revascularization rates keep coming back and I think this generation of drug-eluting stents is clearly different and better than the first generation of DES," offered Davidson.

“If we look at older trials—COURAGE, SYNTAX, among others—what we really have to ask is what were the results of those trials and with past stent technology and present?” said Stone.

Limitations of the study stemmed from the fact that there were extremely low event rates. If we want to get even higher event rates, Stone said that future studies will need to include higher risk populations such as those with acute coronary syndromes, acute MI, multi-lesion disease and bifurcations, among others.

“Most drug-eluting stent events at the lesion site continue to improve over two to three years so I think there are ways to improve this technology but I think it’s getting more and more difficult in clinical trials and it will take larger and larger trials with high risk populations to do so,” Stone said.

From these results, Stone speculated that the FDA will most likely approve this device in the U.S., providing clinicians with another viable stent option.