Vascular access devices, assemblies, kits, and related methods are disclosed. A vascular access assembly may include a first tubular conduit, a second tubular conduit, and an expandable stent graft that is coupled adjacent to a peripheral end of the second tubular conduit. When implanted into the patient, vascular access assemblies may form a flow path that extends from an artery or an arteriovenous graft to a heart of a patient. The vascular access assembly, when implanted and assembled, may be a fully subcutaneous surgical implant.