Zeller: The DEEPER OUS Recoil Data

August 12, 2021 — On Day 2 of this year’s hybrid in-person/virtual AMP conference, Thomas Zeller, MD, delivered a short talk on the Temporary Spur stent system (Reflow Medical) and the DEEPER OUS trial.

The SPUR stent, developed by Reflow Medical, has been designed to address some challenges associated with drug-coated balloon (DCB) and drug-eluting stent (DES) technologies, namely the negative effects of calcification on drug uptake, late lumen loss, and long-term patency and the issue of elastic recoil, which contributes to restenosis and is particularly prevalent in patients with diabetes.

“Moreover, drug uptake maybe limited in arteries with diameter mismatch due to luminal surface contact…which also negatively impacts the drug uptake and penetration,” added Dr. Zeller.

Also, in long lesions and tortuous vessels, DES are “impractical” due to length availability, in particular below-the-knee, he told attendees.

The Spur stent is a temporary, self-expanding nitinol scaffold with radially expandable spikes integrated onto a 6Fr balloon delivery system. The spikes are designed to penetrate through the intima into the media and adventitia, with an integrated balloon to further deploy these spikes and promote delivery drug deep into the vessel wall.

“When followed by a commercially available drug-coated balloon, the temporary mechanical scaffolding may minimize vessel recoil and dissections and increase acute luminal gain. It's intended to deliver stent-like results while leaving nothing behind,” Zeller said.  

DEEPER OUS is a prospective, non-randomized, multicenter study of the Spur stent being conducted in Europe and New Zealand, testing the Spur stent followed by paclitaxel-coated DCB angioplasty in infrapopliteal arteries.

A total of 100 patients will be enrolled and primary patency assessed by duplex ultrasound in subjects free from clinically-drive TLR through 6 months.

The Recoil substudy will include 55 patients who will be assessed at 15 minutes after deployment of the temporary SPUR stent to look for light recoil. Six sites are involved in the DEEPER OUS study, including 4 in Germany, one in Switzerland, and one in New Zealand. 

As of the end of May, 54 of 100 patients had been enrolled in DEPPER OUS. Thus far, there has been no perioperative mortality, no major adverse limb events at 30 days, and 100% freedom from major amputation of the target limb at 12 months.

Nineteen patients have been enrolled into the Recoil substudy, with late recoil seen in 2 of 19, or 10.5%. In those two patients “basically after 15 minutes of waiting time, the luminal gain was negative, which means there was an acute positive gain 15 minutes post removal of the Spur system,” reported Zeller.

“This was exactly the opposite of what was found by Bauman and colleagues from Switzerland. They found elastic recoil in 97% of those patients who had been treated with balloon angioplasty below-the-knee.”

In summary, said Dr. Zeller, “[This] drug-agnostic device creates channels for drug delivery into the artery wall. It's a familiar design with consistent results so far. It’s a mechanical scaffolding intended to reduce vessel recoil, increase acute luminal gain and reduce dissections, creating stent-like acute and chronic results by leaving nothing behind. It preserves future treatment options, and, as mentioned, we have promising initial clinical data coming from DEEPER LIMUS. DEEPER OUS, and the DEEPER first-in-man study.”