The objective of the study is to evaluate early safety and effectiveness of the percutaneous deep foot venous arterialization performed in clinical practice, in an unselected population of patients with "no-option" CLTI.

Critical lower Limb Threatening Ischemia is the most advanced stage of lower limb arterial disease and is associated with a high risk of mortality and major amputation.Literature data indicate that about 5-10% of patients with peripheral arterial disease have a risk of developing CLTI, therefore the most advanced stage of arterial disease of the lower limbs, within 5 years and have a mortality of 20% at 6 months after diagnosis of CLTI.Despite the continuous improvement of the techniques and materials used in the revascularization of these patients, the data of the Literature show that in about 10-15% of these patients revascularization is impossible or ineffective. This condition is defined as: "no-option" CLTI.Therefore, for patients with "no-option" CLTI an alternative treatment for limb rescue may be considered the use of arterialization of the venous plexus of the foot; that is, to use to bring the arterial flow to the foot a healthy conduit, such as the vein, instead of the diseased artery and no longer usable.

The present study is designed as a multicentre, prospective, single-arm, observational study.

All eligible subjects for undergoing PiPER procedure at sites participating in the study will be considered for enrolment and will be asked to give consent prior to participating.

Subjects will be considered enrolled in the study at the time written informed consent is given to the use of their personal data. Once patients are enrolled, their demographics, medical history, disease-relevant conditions, treatment details and outcomes will be collected for up to 24 months from the procedure.

The study will collect information about the medical care patients receive during their planned procedure. No additional testing or procedures will be done.

The revascularization procedure will be performed as per the current clinical practice.

After discharge all patients will attend clinic visits at 30 days (±7 days), 6 months (±14 days),12 months (±30 days), 24 months (±30 days).

Inclusion Criteria:

• Age ≥18 years
• Patient has signed an approved informed consent form
• All patients, with non-revascularizable critical lower limb ischemia defined on the basis of 2 previous unsuccessful Percutaneous Transluminal Angioplasty (PTA) attempts or on severe Medial Artery Calcification (MAC)/Small Artery Disease (SAD) stage.
• Patient with Critical Limb Ischaemia, Rutherford category, 5 (minor tissue loss) or 6 (major tissue loss) with active trophic lesions
• Ejection Fraction > 30%

Exclusion Criteria:

• Subject no able to perform the follow up or other factors making clinical follow-up difficult
• Patients with critical ischaemia of the lower limbs revascularizable by bypass or angioplasty, critical ischaemia characterised by rest pain (Rutherford class ≤ 4)
• Ejection Fraction < 30%

Subjects presenting the most advanced stage of lower limb arterial disease, defined as patients with CLTI and no indication for revascularization.