NEW ORLEANS – A yet-to-be approved platinum chromium everolimus-eluting stent was found to be noninferior to the cobalt chromium everolimus-eluting stent – the most widely used stent in the United States, according to results of the large, randomized PLATINUM trial presented April 4 at the annual meeting of the American College of Cardiology.
At 1 year following implantation, both stents were associated with similar rates of cardiac death, myocardial infarction, and ischemia-driven target lesion revascularization.
Prior to this study, the cobalt chromium everolimus-eluting stent (XSCIENCE V PROMUS) set a new standard for safety and efficacy. The new platinum chromium everolimus-eluting stent (PROMUS Element) incorporates the same concentration of active antiproliferative drug and the same polymer, but uses a different metallic stent backbone whereby platinum replaces cobalt, explained lead author Dr. Gregg W. Stone, professor of medicine and director of cardiovascular research at New York Presbyterian Hospital/Columbia University Medical Center in New York City.
Theoretical advantages of the new backbone include improved deployment, vessel conformability, side branch access, radiopacity, radial strength, and functional resistance, Dr. Stone noted.
"On the basis of this study, I would expect the [Food and Drug Administration] to approve this device in the U.S., giving physicians another option of an excellent stent to use," he added.
The international study was conducted at 132 sites and included 1,530 patients undergoing angioplasty in one or two native coronary arteries with de novo target lesions. Patients were enrolled in the trial between January and September of 2009, and were randomized in a 1:1 ratio to receive either the new platinum chromium stent or the control cobalt chromium stent. Participants are being evaluated at months 1, 6, 12, and 18, and then yearly at years 2-5. At the meeting, Dr. Stone presented 1-year results of the ongoing trial.
Both groups had similar baseline demographic characteristics. Mean age was about 63 years, 71% were male, 72% had hypertension, 77% had hyperlipidemia, 23% had diabetes, 20% were current smokers, 21% had prior myocardial infarction, and 24% had unstable angina. Target lesion characteristics were similar between groups at baseline, including number of lesions treated, diameter, and lesion length. Procedural characteristics also were similar between groups, including the number of stents per patient and per target lesion, maximum stent diameter and length per lesion, and fluoroscopy time.
Technical success, as well as clinical procedural success, was achieved in more than 98% of both groups. Unplanned bail-out stenting was needed in twice as many procedures with the older stent compared with the platinum chromium stent: 9.8% versus 5.9% (P = .004). Inadequate lesion coverage occurred in 3.4% versus 1.4%, respectively (P = .01). Procedural and angiographic outcomes and antiplatelet use were similar for both groups.
For the primary end point of target lesion failure at 12 months, the platinum-chromium stent was noninferior; 2.9% of the cobalt chromium stent versus 3.4% of the platinum chromium stent met the primary end point in a per-protocol analysis. According to an intent-to-treat analysis, 3.2% and 3.5%, respectively, met the primary end point. The incidence of death or myocardial infarction was similar for both groups. Need for ischemia-driven target vessel revascularization was also quite low (around 2.8%) and similar between the groups. Stent thrombosis occurred in 0.4% of each group.
"In this study, 1 in 33 patients had an adverse event at 1 year of follow-up and 1 in 50 had recurrent ischemia with restenosis necessitating revascularization. These are excellent results," Dr. Stone emphasized.
He cautioned, however, that patients included in the trial had simpler coronary lesions, and that experience in a much larger number of patients is needed to be able to tease out true differences between the platinum and the cobalt stents.
Dr. Edward McNulty, an interventional cardiologist at Kaiser Permanente in San Francisco, agreed. At a press conference, he noted that "the different nuances between available stents do not come to light until these devices are used in thousands of patients. This will become evident from large registries and feedback from operators."
"These results are hard to beat," said Dr. Martin Leon, an interventional cardiologist at New York Presbyterian Hospital/Columbia University Medical Center. "The rate of repeat revascularization was really low."
When asked how interventionalists would choose between available drug-eluting stents, Dr. Leon commented, "It’s like the difference between a BMW and an Audi. Subtle differences may appeal more to one person than another. It is going to be very hard to distinguish between them."
Dr. Stone disclosed financial ties with Boston Scientific, which funded the study, Abbott Vascular, and Medtronic. Dr. McNulty had no financial disclosures, and Dr. Leon is an unpaid adviser to several device companies.