Maturation of Arteriovenous Fistula With Automated Sonography Assessments Trial

Inclusion Criteria: * Males or non-pregnant, non-breastfeeding females ≥ 18 years of age but \< 85 years of age at the time of informed consent. * Subject is able and willing to provide written informed consent prior to receiving any non-standard of care, protocol specific procedures. * Subject is willing and capable of complying with all required follow-up visits. * Subject and/or Care Team agree that the distance and transportation resources from the patient's home to the clinic are reasonable for study participation and compliance. * Subject has an estimated life expectancy \> 18 months. * Subject is ambulatory (cane or walker are acceptable). * CKD Stage 5 (eGFR less than 10) or ESRD subjects presenting for upper arm autologous arteriovenous fistula creation that is not transposed for hemodialysis access. * Subjects who are currently on dialysis through a CVC or who imminently require dialysis (GFR \<10). * Vein diameter ≥ 2.5 mm at the antecubital fossa per vein mapping. * Artery diameter ≥ 2.5 mm per vein mapping. * Subject is not participating in another investigational clinical trial that has not met its primary end point. Participation in post-market registry is acceptable. Exclusion Criteria: * CKD Stage 1-4 or subjects that do not require upper arm autologous arteriovenous fistula creation for hemodialysis access. * Subject has history of Steal Syndrome. * Subject who is immunocompromised or immunosuppressed. * Subject has had three previous failed AV fistulae for hemodialysis access. * Subjects expecting to undergo major surgery within 60 days from the EchoMark implantation. * Known or suspected active infection on the day of the index procedure. * Subjects who had infection(s) in the 30-day window prior to EchoMark placement to reduce the likelihood of partially treated infections that can seed the device and fistula. * Subjects with diagnosed bleeding disorder, thrombocytopenia (platelet count \<50,000), hypercoagulability, and history of recurrent deep vein thrombosis not related to AV access. * Subjects with active malignancy. * Subjects with a history of poor compliance with the dialysis protocol. * Subjects with a known or suspected allergy to any of the device materials. * Subjects with an existing fistula or graft. * Subjects who are anticipated to convert to peritoneal dialysis or undergo a transplant within 6 months. * Subjects who are pregnant, planning on becoming pregnant, or are breast feeding.