The study success criteria are: alive on the original TAH-t and free from permanent disabling stroke-related deficits (as evidenced by Modified Rankin Scale score of 0 - 2) at six months post-implant (or transplanted prior to six months post-implant). For the study to be considered a success, eight of the 19 subjects either must be alive at six months on the original TAH-t implant, without experiencing a permanent disabling stroke deficit, or have become transplant eligible (or have been transplanted).