FDA Approves Resolute Onyx, Billed as Slimmest Stent Yet on US Market

The US Food and Drug Administration (FDA) has approved the “smallest-sized” stent to date—the Resolute Onyx 2.0-mm zotarolimus-eluting stent—the device’s manufacturer, Medtronic, announced today. Additionally, according to the company, the system permits the “lowest crossing profile of any DES” at less than 1 mm, “enabling exceptional deliverability.”

Resolute Onyx, which has a strut thickness of 81 μm, was approved based on results from the RESOLUTE ONYX 2.0 mm stent study, presented last year at EuroPCR 2017.

In the study, the 101 patients from the United States and Japan had de novo lesions < 27 mm in length with a reference vessel diameter of 2.0 mm or greater, but less than 2.25 mm, by visual estimation. All underwent FFR to confirm significant stenoses. The primary endpoint of target lesion failure was 5.0% at 1 year, which was significantly lower than the performance goal of 19%. TLR was only 2% at 1 year, and there were three target-vessel MIs and no instances of stent thrombosis.

This is the slimmest stent the FDA has ever approved, although it joins the increasing market of low-profile devices including the 2.5 mm EluNIR ridaforolimus-eluting stent (Cardinal Health and Medinol), which boasts a combination of “flexible” 40-µm struts and 72-µm “supportive” struts. The EluNir got the FDA’s go-ahead in November.

The Resolute Onyx 2.0-mm DES gained CE Mark approval in Europe in November 2014.

"Patients with lesions in small vessels or complex vasculatures can present unique challenges for physicians during PCI procedures,” the trial’s lead investigator, Matthew Price, MD (Scripps Clinic, La Jolla, CA), said in a press release announcing the approval today. Further, the stent is “extremely deliverable” and “when needed, can be postdilated to 3.25 mm to treat lesions in difficult-to-reach areas of the heart.”

Of note, during the original presentation of the Resolute Onyx data, there was some discussion about whether lesions in small vessels even need stenting, with some experts suggesting that balloon angioplasty alone may do the trick.

However, Price told TCTMD in an email that currently balloon angioplasty “is complicated by dissection, recoil, and restenosis, particularly in small vessels.” While there are no current data comparing the restenosis rates of angioplasty versus the Resolute Onyx stent in lesions with a reference vessel diameter ≤ 2.0 mm, “a stent would likely provide safer outcomes in this challenging lesion subset,” he added. “In the Onyx 2.0 study, there was no signal for stent thrombosis and the DES met its prespecified performance criteria for target lesion failure by a large margin. Of note, DES of 2.25 mm diameter have been robustly adopted by clinicians despite a similar lack of data comparing these stents to [plain old balloon angioplasty].”