• BIOFLEX-I: Astron Pulsar, Pulsar-18 Stents Safe, Effective in Peripheral Disease at 3 Years

    The Astron Pulsar and Pulsar-18 self-expanding nitinol stents are safe and effective for treatment of lesions in the superficial femoral artery (SFA) and proximal popliteal artery (PPA), with good clinical and quality-of-life results at 3 years, according to study results presented Friday at CRT 2021 Virtual.

    Mark W. Burket, MD, of the University of Toledo, Ohio, presented 3-year results of the BIOFLEX-I trial.

    Self-expanding stents continue to play a key role in the treatment of peripheral arterial disease. Long-term outcomes are of vital importance.

    The Pulsar-18 and Astron Pulsar self-expanding nitinol stents (Biotronik) are available in diameters of 4 to 7 mm and lengths of 20 to 150 mm. They have a durable, multi-directional, flexible design; strut thickness of 140 micrometers; and a 4-French profile.

    BIOFLEX-I is a prospective, international, two-arm investigational device exemption trial independently powered for evaluating the Astron (iliac) and Pulsar (SFA/PPA) stent groups. It enrolled 302 patients in 38 centers in the U.S., Canada and Europe.

    Inclusion criteria included adult candidates for percutaneous transluminal angioplasty with lifestyle-limiting claudication or rest pain with an ankle-brachial index (ABI) ≤0.9 at rest or with exertion. Lesion length was ≤190 mm if de novo or restenotic or ≤100 mm if occluded.

    Exclusion criteria included Rutherford-Becker category 5 or 6, although patients with ulcers caused by venous disease were allowed to enroll. Other exclusion criteria were prior peripheral vascular bypass involving the target limb, previously stented lesions in the target vessel, treatment of the target lesion within the previous 30 days, additional percutaneous interventional procedures planned within 30 days of the index procedure, and excessive tortuosity or calcification or location next to an acute thrombus that does not respond to antithrombotic therapies.

    Both stents received premarket approval from the U.S. Food and Drug Administration in 2017 based on 1-year study results. The post-approval study’s long-term primary endpoint was freedom from clinically driven target lesion revascularization (CD-TLR) and index limb amputation at 36 months. Long-term secondary endpoints were freedom from CD-TLR and index limb amputation at 24 months, major adverse events (MAE) at 24 and 36 months, individual MAE component rates, stent fracture rate at 24 and 36 months, and adverse event rates.

    At baseline, the patients had a mean age of 67.3±10.3 years, 67.9% were men, mean ABI was 0.70±0.14  and the majority (90%) had moderate or severe claudication. Also, 72.8% of lesions were moderately or severely calcified.

    At 36 months after the procedure, 81.5% of patients were free from CD-TLR and index limb amputation. The long-term MAE rates were 19.3% at 2 years and 22.1% at 3 years, which was driven by CD-TLR (19.0% at 2 years and 21.8% at 3 years). Stent fracture rates were 3.1% at 1 years, 4.0% at 2 years and 5.7% at 3 years; no stent fracture was causally associated with TLR, amputation or death.

    ABI improved from 0.70 at baseline to 0.91 at 12 months (mean change from baseline 0.22±0.21; p<0.001). Six-minute walk distance improved from 875.3 feet at baseline to 1,088.9 feet at 12 months. Walking Impairment Questionnaire scores showed similar improvements.

    The results, Burket said, support “the safety and efficacy of Astron Pulsar and Pulsar-18 stents for treatment of the superficial femoral and proximal popliteal arteries” and that 4-French compatibility may reduce procedure-related complications.

    Burket disclosed that he is a consultant for Biotronik. The study was sponsored by Biotronik.

    CRT 2021 Virtual takes place Fridays and Saturdays through April 24. On-demand content from the meeting is available here.

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