Shockwave ®S4 Catheter IVL to Treat Infrapopliteal Calcified Stenoses and/or Occlusions in CLTI Patients (LEGACY)

Inclusion Criteria: * Age ≥18 years * Patient has signed an approved informed consent form * Patient with Critical Limb Ischaemia, Rutherford category 4 (ischaemic rest pain), 5(minor tissue loss) or 6 (major tissue loss) * Patient with Stenotic (\>50% luminal loss) or occluded infrapopliteal artery, including the tibiofibular trunk, the anterior tibial artery, the posterior tibial artery and the peroneal artery * The vascular lesion length will be no longer than 150 mm. * Patient with no significant disease at the inflow: common iliac, external iliac, superficial femoral and popliteal artery on the ipsilateral side prior to enrollment, and patient with no significant disease at the outflow - runoff to ankle level: plantar for posterior tibial, pedal for anterior tibial, anterior and posterior perforant branches for peroneal vessels or previous successful revascularization of the disease segments (inflow-outflow) * Live expectancy \> 1 year. * Presence at least ≥1 filling pedal vessel on the target limb. Exclusion Criteria: * Subject pregnant or planning to become pregnant during the study * Subject no able to perform the follow up or other factors making clinical follow-up difficult * Acute or Subacute limb ischaemia which requires thrombolysis as first treatment modality or previous thrombolytic therapy in the last 48-72 hours. * Known allergy to concomitant medication, antiplatelet anti-coagulant or thrombolytic medication * Poor inflow due to ipsilateral stenoses or occlusions of the iliac or femoropopliteal arteries * Significant stenoses (\> 50%) distal to the target lesion that might require revascularization or impede run-off * Desert foot condition. No Patent foot main arteries * Subject enrolled in another investigational study that has not reached its primary endpoint