Hybrid synthetic grafts and embodiments of systems and methods for producing hybrid vascular grafts that can yield implantable grafts that combine synthetic grafts with living cells. Embodiments of systems can include a pressure/flow loop subsystem having an external flow loop system coupled to a specimen holder, where the pressure/flow loop subsystem is capable of adjusting at least two dynamic conditions in the specimen holder or a diameter of a specimen in the specimen holder. Embodiments of methods can coat a hybrid graft with a confluent monolayer of endothelial cells by immobilizing stem cells on a hybrid hemodialysis access graft or a hybrid femoral artery bypass graft, and placing the hybrid graft in a system embodiment according to the invention under conditions effective to promote the stem cells to form a confluent monolayer on the hybrid graft and in an environment to promote the stem cells to differentiate into endothelial cells.
