IMPERIAL: DES with polymer coating offers superior patency in PAD
SAN DIEGO — Patients with peripheral artery disease who received a drug-eluting stent with a polymer coating and a lower drug dose density had better patency compared with a DES without a polymer coating and a higher drug dose density, according to 12-month results from the IMPERIAL trial presented at TCT 2018 and published in The Lancet.
The DES with polymer coating (Eluvia, Boston Scientific) also was noninferior for target lesion revascularization and stent thrombosis than the DES without a polymer coating (Zilver PTX, Cook Medical).
William A. Gray, MD, system chief of the division of cardiovascular disease at Main Line Health and president of the Lankenau Heart Institute in Wynnewood, Pennsylvania, and colleagues performed a head-to-head trial comparing the two DES in 465 patients with Rutherford category 2, 3 or 4; at least one lesion in the native superficial femoral artery and/or the proximal popliteal artery; stenosis greater than 70%; vessel diameter between 4 mm and 6 mm; and total lesion length between 30 mm and 140 mm.
“We have a lot of very good trials, which are core-lab controlled and well-run and constructed and have led to FDA approvals of multiple devices, stents, balloons, atherectomy devices and so on,” Gray told Cardiology Today’s Intervention. “The problem with those trials is that many of them were compared to the balloon angioplasty as their predicate. Today, balloon angioplasty is no longer the standard of care.”
Therefore, patients were randomly assigned the Eluvia DES (n = 309; mean age, 69 years; 66% men) or the Zilver PTX DES (n = 156; mean age, 68 years; 67% men), both of which elute paclitaxel. The Eluvia stent is not yet approved for use in the United States.
“The difference in the pharmacokinetics of this is that the payload of Zilver PTX is delivered immediately,” Gray said during the press conference. “Because of paclitaxel amphiphilic, it resides in the tissue for a certain period of time. With a biostable polymer, it can be eluted over a longer period of time. Noteworthy in the SFA is that the peak incidence of restenosis is around 9 to 10 months, so we need a much longer duration of drug elution.”
The primary effectiveness endpoint was primary vessel patency as assessed by duplex ultrasound, at 12 months. The primary safety endpoint was the major adverse event rate, defined as target limb major amputation at 12 months, all-cause death at 1 month and TLR at 12 months.
Compared with patients assigned Zilver PTX, those assigned Eluvia had longer lesion lengths (86.5 mm vs. 81.8 mm), were more likely to have severe calcification (40.1% vs. 32.3%) and were more likely to have total occlusion (31.2% vs. 30.3%).
At 12 months, the rate of primary vessel patency was higher in the Eluvia group vs. the Zilver PTX group (86.8% vs. 77.5%; difference = 9.3; 95% CI, 1.4-17.3). The Kaplan-Meier analysis of primary vessel patency had similar results (88.5% vs. 79.5%; P = .0119).
Eluvia was noninferior to Zilver PTX for major adverse events (4.9% vs. 9%; difference = –4.1%; 95% CI, –9.4 to 1.2; P = .0975). Compared with patients assigned Zilver PTX, those assigned Eluvia also had numerically lower rates of clinically driven TLR (4.5% vs. 9%; difference = –4.4; 95% CI, –9.7 to 0.8) and stent thrombosis (1.7% vs. 4%; difference = –2.3; 95% CI, –5.8 to 1.2).
“What [Boston Scientific] did was they used the durable polymer that’s on their coronary stent and they transferred that largely intact to the Eluvia stent,” Gray said in an interview. “That permitted them to elute paclitaxel over a much longer period of time. That has led to the results that you’re seeing today.”
At 12 months, most patients were Rutherford category 0 or 1 (Eluvia, 85.8%; Zilver PTX, 84.5%).
“We’re talking now about a world in which the SFA, a longer, more complex vessel, is achieving near-coronary levels of TLR, which I don’t think 5 to 10 years ago any of us would have predicted,” Gray told Cardiology Today’s Intervention. “Absent even the comparison between the two devices, if you just look at the stand-alone results of the Eluvia stent, [it] is impressive and will change or at least affect global practice.”
Most patients in both groups had ankle-brachial index improvements at 12 months, although they were not significantly different. Both groups also had significant improvements in walking impairment from baseline to 12 months.
“I’m hoping this will move the needle a little bit in terms of how we currently treat patients,” Gray said in an interview.
"We are pleased by the superior results exhibited by the Eluvia stent," Ian Meredith, MD, executive vice president and global chief medical officer of Boston Scientific, said in a press release. "The results from the IMPERIAL trial add to the growing body of evidence supporting the use of the Eluvia stent as a frontline therapy for patients, even those suffering from the most challenging cases of superficial femoral artery disease." – by Darlene Dobkowski
Reference s :
Gray WA, et al. Late-Breaking Trials 1. Presented at: TCT Scientific Symposium; Sept. 21-25, 2018; San Diego.
Gray WA, et al. Lancet. 2018;doi:10.1016/S0140-6736(18)32262-1.
Disclosure s : The study was funded by Boston Scientific. Gray reports that he is an adviser for Boston Scientific. Meredith is an employee of Boston Scientific.