Transcatheter aortic valve implantation (TAVI): valve design and evolution.

The efficacy of transcatheter aortic valve implantation (TAVI) in high surgical risk and inoperable patients with severe aortic stenosis (AS) is rapidly gaining credibility with an ever-expanding body of supporting evidence. The potential of TAVI to be a treatment option for a significant cohort of patients with aortic stenosis has fuelled a drive for the optimum device and resulted in exponential advances in the technology with a focus on adverse event minimization and procedural simplification. Consequently, a plethora of new transcatheter valve choices are now available for clinical study or in the pipeline. The evaluation of past, current and emerging devices allows for an appreciation of the design considerations involved in this process and an insight to the future direction of the technology.