Inclusion Criteria:  The patient must be a member or beneficiary of a health insurance plan Patients receiving a scheduled venous allograft within the CHU of Nîmes for an arterial bypass in the lower limb or an arteriovenous bypass in the upper limb within the framework of the creation of arteriovenous fistulas in dialysis patients, in the absence of available autologous venous material.  Exclusion Criteria:  The subject is participating in a category 1 interventional study, or is in a period of exclusion determined by a previous study The subject has already been included in the study The subject refuses to participate It is impossible to give the subject informed information The patient is under safeguard of justice or state guardianship Patient previously having received a venous allograft or organ transplant Pregnant, parturient or breastfeeding patients Presence of donor-specific antibodies in HLA-immunized patients