Is tissue-engineered heart valve replacement clinically applicable?

Tissue engineering of a heart valve has progressed dramatically in three different arenas: a biodegradable stented valve seeded with autogenous cells, decellularized allograft and xenograft valves that are seeded with autogenous cells, and decellularized allograft and xenograft valves that repopulate by adaptive remodeling in vivo. Preclinical evaluation and implants in sheep have been accomplished in each of these arenas, and clinical use of this emerging technology is occurring in the latter two. The clinical use of decellularized allografts that repopulate in vivo is expanding; however, its impact on allograft durability remains unknown.