Study Protocol for the Evaluation of Morphologic and Imaging Remodeling of Atherosclerotic Plaque Following Intravascular Lithotripsy in Peripheral Artery Disease

Background: Intravascular lithotripsy (IVL) has emerged as a novel vessel preparation device for patients with peripheral artery disease undergoing angioplasty. The IVL catheter includes an integrated balloon, which emits high pressure and transient sonic waves. The release of shockwaves results in cracking of intimal and medial calcium within the vessel wall improving lumen patency. Objectives: The aim of this prospective observational cohort study is to evaluate the morphological and imaging changes in atherosclerotic plaque in patients with PAD undergoing IVL as a vessel preparation technique, followed by angioplasty with drug-coated balloon (DCB) or stent placement if required. Secondary endpoint is to evaluate the efficacy of IVL in the perfusion of the lower extremities, by calculating the ankle–brachial index (ABI) and toe–brachial index (TBI) post-angioplasty, as well as adverse events within 30 days. Methods: Consecutive adult (≥18 years of age) patients with symptomatic femoropopliteal artery disease selected to undergo IVL will be included in the study. Computed tomography angiography (CTA) of the lower limbs will be performed pre- and postoperatively. Intraoperatively, an intravascular ultrasound (IVUS) will be used before and immediately post-angioplasty, for real-time evaluation of the morphological and quantitative changes in the atherosclerotic plaque. All participants will be clinically re-evaluated in 30 days postoperatively and a color Duplex ultrasound of the lower extremity arteries will be performed. The perfusion of the peripheral arteries will be assessed using ABI and TBI post-procedurally. Outcomes: The primary outcome is the quantitative assessment of changes in plaque morphology and volume within the index target lesion, based on pre- and post-procedural computed tomography angiography using TeraRecon™ (Durham, NC, USA) plaque analysis module, reflecting plaque modification and redistribution, in the context of IVL-based vessel preparation. Secondary outcomes include improvement of peripheral arterial perfusion and freedom from clinically driven target lesion revascularization (CD-TLR) and major adverse events.