CHICAGO—The outcomes reported at 12 months comparing the safety and effectiveness of the Promus Element everolimus-eluting platinum chromium stent to Xience V, or Promus original, everolimus-eluting stent, remained comparable at two years, based on the prospective, multicenter, randomized PLATINUM Workhorse trial, presented March 25 at the 61st annual American College of Cardiology (ACC) scientific session. However, an additional landmark analysis of outcomes from year one to year two demonstrated superior efficacy of Promus Element compared with Xience V during this 12-month follow-up period.
The study’s principal investigator, Gregg W. Stone, MD, director of research and education at the Center for Interventional Vascular Therapy at Columbia University Medical Center/New York-Presbyterian Hospital in New York City, and colleagues enrolled 1,530 patients randomized at 132 clinical sites in Asia/Pacific (56 patients), European Union (562 patients), Japan (124) and the U.S. (788 patients).
The patients initially were randomized to either the Xience V (762 patients) or the Promus Element (768 patients). At two-year follow-up, the Xience V arm had 724 patients and the Promus Element arm had 736 patients.
Stone reported a two-year target lesion failure (TLF) rate of 4.4 percent for the Promus Element Stent compared to 5.8 percent for the Xience V. The Promus Element demonstrated numerically lower, but not statistically different, event rates than the Xience V in TLF components at two years, including cardiac death related to the target vessel (0.9 percent vs. 1.1 percent, respectively), MI related to the target vessel (1.2 percent vs. 2.1 percent) and ischemia-driven target lesion revascularization (TLR, 2.4 percent vs. 4 percent).
According to the researchers, the low rates of target vessel revascularization (TVR, 4.2 percent vs. 5.6 percent) and stent thrombosis (ARC definite/probable, 0.5 percent vs. 0.7 percent) were observed at two years for both stents. “There were no adjudicated ARC probable stent thrombosis events through two-year follow-up,” Stone said.
In a landmark analysis of event rates from year one to year two, the Promus Element demonstrated statistically significant differences in TLF (1.2 percent vs. 3 percent—a 56 percent relative reduction), and TLR (0.7 percent vs. 2.2 percent—a 67 percent relative reduction) compared to the Xience V, showing superior efficacy of the Promus Element Stent from 12 months to two years.
Stone added that the results confirmed a previously reported significant reduction in unplanned (bail-out or emergency) stenting with the Promus Element (5.9 percent vs. 9.8 percent), including a significantly lower rate of inadequate lesion coverage or "geographic miss" (1.4 percent vs. 3.4 percent).
Acknowledging the limitations of the trial, Stone noted that patients with acute MI, chronic total occlusions, bifurcations, left main coronary artery lesions, saphenous vein graft lesions, ostial lesions and lesions with thrombus, excessive tortuosity or calcification were excluded. Also, “the trial was not designed to assess differences between stent types in deliverability, acute performance or ease of use.”
Stone concluded that a significant reduction in ischemia-driven repeat TLR was present between the first and second year of follow-up with the Promus Element compared with the Xience V. “This finding, while potentially important, must be confirmed by longer-term follow-up,” Stone said.
The PLATINUM Workhorse trial is funded by Boston Scientific of Natick, Mass.