RESTORE ATK and RESTORE BTK Results Reported for Bolt IVL System

November 4, 2024—The RESTORE ATK and RESTORE BTK trials assessed the laser- and optics-based Bolt peripheral intravascular lithotripsy (IVL) system (Bolt Medical) for the treatment of, respectively, above-the-knee (ATK) and below-the-knee (BTK) calcified lesions. The prospective, nonrandomized, multicenter studies were conducted in Europe.

Thomas Zeller, MD, presented the findings from the two studies in the first late-breaking clinical trials session at VIVA24, the 22nd annual Vascular InterVentional Advances annual vascular education symposium held by The VIVA Foundation on November 3-6 in Las Vegas, Nevada.

The VIVA24 press release noted that arterial calcification portends poor procedural success for peripheral vascular interventions and suboptimal long-term outcomes. These studies aimed to evaluate the initial safety and efficacy of the Bolt IVL system in calcified ATK and BTK lesions.

As summarized by VIVA24, patients in the ATK and BTK studies were treated with IVL and followed out to 6 months and 30 days, respectively.

The primary safety endpoints were freedom from major adverse events (MAEs; a composite of death, clinically driven target limb revascularization [CD-TLR], and unplanned major amputation) within 30 days after the index procedure. Efficacy endpoints included procedural success (residual diameter stenosis < 50%) evaluated by an independent core laboratory.

The ATK study enrolled 95 patients (mean age, 70 ± 8 years; female, 33%). The BTK study enrolled 20 patients (mean age, 73 ± 10 years; females, 30%).

The superficial femoral and anterior tibial arteries were the most treated in each trial, with a mean vessel diameter of 5.5 ± 0.7 mm and 2.9 ± 0.4 mm, respectively, and percent diameter stenosis of 93.7% ± 7.2% and 91.4% ± 8.8%, respectively.

The VIVA24 press release reported the following results:

• The efficacy endpoint was achieved in 100% of patients in both studies.
• Residual diameter stenosis postprocedure was 21.2% ± 8.4% (ATK) and 22.8% ± 11.5% (BTK) with no MAEs occurring within 30 days.
• No cases of perforation, abrupt closure, no reflow, distal embolization, or dissections meeting serious AE criteria were observed.
• No stents were placed in BTK patients.
• Only three stents were placed in ATK patients despite the lesion complexity, length, and chronic total occlusions.
• In the 92 ATK patients who completed 6-month follow-up, CD-TLR was 2.2%.
• In the 18 BTK patients who completed 30-day follow-up, CD-TLR was 0%.
• There were no deaths or limb amputations in either study.

The studies demonstrate the safety and effectiveness of this novel laser and optics-based IVL catheter for treatment of severely calcified ATK and BTK peripheral lesions, concluded the VIVA24 press release.