After obtaining Institutional Review Board (IRB) approval, baseline demographic and clinical data was collected. Following surgery, implant procedure data was collected on study participants who received HeRO Grafts. HeRO Grafts were placed using a 2-step process with initial placement of the ePTFE portion, followed by completion of the graft by placement of the venous outflow component. Following enrollment, outcomes of interest were collected at follow-up visits scheduled weekly for 4 weeks, bi-weekly for 3 months, and monthly to 1 year, for a total of 18 follow-up visits. Study coordinators documented post-operative complications, incidence of thrombosis, hospitalizations, infection incidents, and deaths at each follow-up.