Sirolimus Coated BALloon Versus Standard Balloon Angioplasty in The Treatment of Below The Knee Arterial Disease

The burden of limb loss because of peripheral arterial disease (PAD) is high and this problem is set to worsen globally. Treatment of PAD primarily involves revascularisation of the limb. Angioplasty as a first line strategy of revascularization over surgical procedures has been adopted by many vascular centres. In recent years, studies have shown that local drug delivery using drug coated balloons (DCB) during angioplasty for PAD can successfully deliver effective local tissue concentrations of antiproliferative drugs to the lesions in the artery involved in the PAD. This offers the potential for sustained anti-restenotic efficacy.

Randomized trials have shown superiority of Paclitaxel DCBs over just plain-balloon angioplasty for treatment of femoropopliteal occlusive disease, and DCB is now considered the standard of care in many regions. However, the efficacy of Paclitaxel below the knee is less clear, as multiple randomized trials evaluating Paclitaxel-coated DCBs below the knee have failed to meet their primary endpoints. Alternative drugs for DCBs are therefore needed and sirolimus may offer an attractive alternative. Compared to Paclitaxel, sirolimus is cytostatic in its mode of action with a high margin of safety. It has a high transfer rate to the vessel wall and has been shown to effectively inhibit neointimal hyperplasia in the porcine coronary model. In the coronary artery interventions, preliminary clinical studies using Sirolimus DCBs have also shown excellent procedural and 6- & 12- months patency. This study aims to conduct a single blind, randomised controlled multicentre trial of sirolimus drug coated balloon versus standard percutaneous transluminal angioplasty in patients with below the knee arterial disease.

Inclusion criteria

• Age ≥ 21 years or minimum age (is allowed the inclusion of subjects > 21 years OR adulthood minimum age (depending on the US state regulations)
• Rutherford class 4 with documented WIFI score, not exceeding more than 30% of target patient population.
• Rutherford class 5 to 6 in the target limb with documented WIFI score.

Intraoperative Inclusion Criteria:

• Single or sequential de novo or re-stenotic lesions (stenosis of > 50% or occlusions) from 2 to 20cm in the proximal 200mm of below the knee arteries. Lesion is considered as one lesion if there is maximum of 30 mm gap between lesions at discretion of investigator. Below the knee arteries are Tibio-peroneal trunk, Peroneal bifurcation, anterior tibial artery, posterior tibial artery and peroneal artery. With documented Distal Run off a maximum of two tibial vessels can be treated in the index procedure. Inflow free from flow limiting lesions (<50% stenosis) confirmed by duplex or angiography. Subjects with flow limiting inflow lesions (>50% stenosis) can be included if lesion had been treated successfully (<30% residual stenosis) before or during the index procedure.
• Target vessel has angiographically documented unimpaired (<50% stenosis) run off into a named Tibio-pedal artery (Peroneal, Anterior Tibial/ Dorsalis Pedis/ Posterior Tibial Artery)

Exclusion criteria

• Comorbid conditions limiting life expectancy ≤ 1 year
• Subject is currently participating in another investigational drug or device study that has not reached first primary endpoint yet
• Subject is lactating, pregnant or planning to become pregnant during the course of the study
• Subject with extensive tissue loss salvageable only with complex foot reconstruction or non-traditional trans metatarsal amputation. This includes subjects with:

• Osteomyelitis including and/or proximal to the metatarsal head
• Gangrene involving the plantar skin of the forefoot, midfoot,or heel
• Deep ulcer or large shallow ulcer (> 3 cm) involving the plantar skin of the forefoot, midfoot, or heel
• Full thickness heel ulcer with/without calcaneal involvement
• Any wound with calcaneal bone involvement
• Wounds that are deemed to be neuropathic or non-ischemic in nature
• Wounds that would require flap coverage or complex wound management for large soft tissue defect
• Full thickness wounds on the dorsum of the foot with exposed tendon or bone
• Prior bypass surgery of target vessel
• Planned amputation of the target limb (major)
• Previously implanted stent in the target lesion
• Vulnerable or protected adults
• Bleeding diathesis or another disorder (i.e. gastrointestinal ulceration,etc) which would prevent the use of mandated antiplatelet agents
• Known allergy to sirolimus
• Subjects with severe (Stage 4) renal disease, defined eGFR < 30.

Intraoperative exclusion criteria:

• Failure to successfully cross the target lesion with a guide wire
• Target vessel has lesions extending beyond the ankle joint
• Failure to obtain <30% residual stenosis prior to randomization
• Lesions requiring treatment through retrograde access . Retrograde wire crossing is allowed but treatment must be performed from the antegrade approach.
• Use of commercially available DCBs, bare metal stents, drug eluting stents, specialty balloons or atherectomy devices at the target lesions. (Non-compliant balloons are not considered specialty balloons). For Inflow and non-target lesions all the approved devices are allowed.