Engineered tissue vascular grafts: Are we there yet?

Over the last 20 years, a diverse number of different approaches have been explored in trying to produce engineered tissue vascular grafts (ETVGs). If successful, this alternative source of living vascular conduits with the ability to grow, remodel, and self-repair could revolutionize vascular surgery by relieving the limiting need for autologous grafts or providing substantial benefit and improved performance over their synthetic counterparts. However, despite tissue engineering being one of the hottest topics in biotechnology in the last three decades, it is generally acknowledged that the field's performance and its potential clinical translation have been somewhat disappointing. Pilot studies with ETVGs in animal models and preclinical human trials have been encouraging, but our understanding of the design requirements for ETVGs, how to effectively create them, and how to direct ETVG integration once implanted must be improved. This article reviews the current state-of-the-art of ETVGs with emphasis on the different manufacturing approaches explored in the past and challenges encountered and tackled, with particular focus on ETVGs that are very close to making a clinical impact and may potentially begin a new era of therapy for vascular disease.