The goal of this observational study is to increase the understanding of the safety and performance of Merit Medical's HeRO Graft System (HeRO) and Super HeRO Adaptor and Support Seal System (Super HeRO) devices. This study includes adults that are being treated with one of these devices as part of their regular medical care for maintaining long-term dialysis access when all other dialysis access options have failed. If participants in the study are not seen for a standard of care clinic visit during the 4 visit timepoints over 2 years, the participant will be followed by phone to check their current health and dialysis status.