Prospective Feasibility Study Evaluating EchoMark LP Placement and EchoSure Measurements for Subjects Requiring Arteriovenous Fistulae

Inclusion Criteria: 1. Males or non-pregnant, non-breastfeeding females ≥ 18 years of age but \< 85 years of age at the time of informed consent 2. Subject is able and willing to provide written informed consent prior to receiving any non-standard of care, protocol specific procedures 3. Subject is willing and capable of complying with all required follow-up visits 4. Subject and/or Care Team agree that the distance and transportation resources from the subject's home to the clinic are reasonable for study participation and compliance 5. Subject has an estimated life expectancy \> 18 months 6. Subject is ambulatory (cane or walker are acceptable) 7. Subjects presenting for upper arm autologous arteriovenous fistula creation 8. Vein diameter \> 2.5 mm at the antecubital fossa via imaging 9. Artery diameter \> 3 mm via imaging 10. Subject is not participating in another investigational clinical trial that has not met its primary endpoint. Participation in a post-market registry is acceptable. Exclusion Criteria: 1. Subjects receiving a forearm fistula. 2. Subject has history of Steal Syndrome. 3. Subject who is immunocompromised or immunosuppressed. 4. Subject has had three previous failed AV fistulae for hemodialysis access 5. Subjects expecting to undergo major surgery within 60 days from the EchoMark implantation. 6. Known or suspected active infection on the day of the index procedure. 7. 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 8. Subjects with diagnosed bleeding disorder, thrombocytopenia (platelet count \<50,000), hypercoagulability, and history of recurrent deep vein thrombosis not related to AV access 9. Subjects with active malignancy 10. Subjects with a history of poor compliance with the dialysis protocol 11. Subjects with a known or suspected allergy to any of the device materials 12. Subjects with an existing fistula or graft 13. Subjects who are pregnant, plan to become pregnant, or are breastfeeding.