Safety and effectiveness of the Chocolate balloon catheter in the treatment of peripheral artery disease with percutaneous transluminal angioplasty: a multicentre, prospective, observational study protocol.

backgroundPeripheral artery disease (PAD) represents a significant global health burden. Percutaneous transluminal angioplasty (PTA) is the most commonly employed endovascular intervention; however, its long-term efficacy is often compromised by restenosis and flow-limiting dissection. The Chocolate balloon catheter, characterised by a nitinol-constrained design that enables controlled, segmental vessel dilation, has demonstrated potential in minimising vascular trauma and enhancing patency. Nevertheless, there remains a lack of robust multicentre evidence evaluating its safety and effectiveness in real-world Chinese PAD populations. This protocol outlines a prospective, multicentre, single-arm observational study aiming to assess the 12 month primary patency and complication rates following Chocolate balloon PTA in Chinese patients with femoropopliteal or infrapopliteal lesions. METHODS AND ANALYSIS: This prospective, multicentre, single-arm observational study will be conducted across eight medical centres in China. Eligible patients with symptomatic PAD (Rutherford classification 2-5) and de novo or restenotic lesions in the femoropopliteal or infrapopliteal arteries, for whom the use of a Chocolate balloon catheter is indicated as per standard care, will be enrolled. All participants will undergo percutaneous transluminal angioplasty using the Chocolate balloon catheter and will be followed up for 12 months. The primary outcome is the primary patency rate of the target lesion at 12 months, defined as the absence of restenosis (diameter stenosis <50% by duplex ultrasound with a peak systolic velocity ratio <2.5) and freedom from target lesion revascularisation. ETHICS AND DISSEMINATION: The study protocol was approved by the Clinical Trial Ethics Committee of Hangzhou First People's Hospital (Approval No. IIT-20220606-0082-01). The findings will be disseminated in peer-reviewed publications. TRIAL REGISTRATION NUMBER: NCT06933992.