Transcatheter Aortic Valve Replacement in Patients with Critical Aortic Stenosis: Rationale, Device Descriptions, Early Clinical Experiences, and Perspectives

The development of lesser invasive transcatheter techniques for aortic valve replacement (AVR) to treat high surgical risk patients with severe aortic stenosis (AS) has engendered controversy among traditional cardiovascular therapists. Presently, there are two catheter-based treatment systems (the Cribier–Edwards Aortic Bioprosthesis™ and the CoreValve Revalving™ System) utilizing either a balloon-expandable or a self-expanding stent (or cage) platform which unfolds a pericardial tissue valve within the displaced diseased aortic valve. After ex vivo durability testing and animal studies, several clinical registries with these transcatheter AVR systems in almost 300 patients worldwide have demonstrated the following: (1) good acute hemodynamic performance with reduction in mean aortic valve gradients to <10 mm Hg; (2) frequent para-valvular regurgitation, which has improved with self-expanding devices and the use of larger (26 mm) valve sizes; (3) acceptable periprocedural (30-day) mortality (<10%) with the newest generation devices and improved operator techniques. Enlightened interdisciplinary treatment teams incorporating surgeons, interventionalists, and medical therapists as well as rigorously conducted randomized clinical trials will be required to determine if these innovative transcatheter AVR approaches will represent a viable therapy for high-risk patients with severe AS in the future.