Thirty-day outcomes from the Disrupt PAD BTK II study of the Shockwave Intravascular Lithotripsy System for treatment of calcified below-the-knee peripheral arterial disease.

Background: Below-the-knee (BTK) lesions may be particularly challenging to treat owing to length, diffuse disease, and extent of calcification. Landmark interventional clinical studies have not reached consensus on the optimal standard of care for BTK lesions, and many published trials excluded patients with moderate or severe lesion calcification. Calcium modification with intravascular lithotripsy (IVL) was shown to be superior to percutaneous transluminal angioplasty in the femoropopliteal artery and successful in treating BTK lesions in pilot studies. The Disrupt BTK II study is a core laboratory-adjudicated, prospective, multicenter, single-arm study of patients with moderate to severely calcified BTK lesions treated with the Shockwave Medical Peripheral IVL System.

Methods: Disrupt BTK II enrolled 250 subjects with calcified infrapopliteal lesions and Rutherford category 3-5 presentation from 38 sites in the United States and Europe. The primary safety endpoint was major adverse limb events or postoperative death at 30 days, a composite of all-cause death, above-ankle amputation of the index limb, and/or major reintervention of the index limb involving an infrapopliteal artery. The primary effectiveness endpoint was procedural success, defined as ≤50% residual stenosis for all treated target lesions without serious core laboratory-adjudicated serious angiographic complications. The study used independent angiographic and duplex ultrasound core laboratories, and follow-up is planned through 2 years.

Results: A total of 305 lesions in 250 patients were treated with a procedural success of 97.9%. The mean target lesion length was 76 ± 65 mm, diameter stenosis was 78% ± 18%, and 84.8% had moderate or severe calcification as assessed by an independent angiographic core laboratory. After IVL, residual stenosis was reduced to 29%, and after optional postdilatation and/or stent implantation, to 26%. At 30 days, there were no deaths, major adverse limb event rate was 0.8%, and mean improvement in Vascular Quality of Life scores was 4.0 ± 5.0 (P < .0001). Of the patients with baseline wounds, 15.8% healed and 53.4% were improved at 30 days.

Conclusions: The Disrupt PAD BTK II study demonstrated that treatment with the Shockwave Medical Peripheral IVL System in patients with moderate-severe calcified lesions resulted in high procedural success, significant reduction in residual stenosis, improvements in patient quality of life, and wound healing, with minimal adverse events at 30-day follow-up.