© Europa Digital & Publishing 2015. All rights reserved. Aims: Transcatheter aortic valve implantation (TAVI) is an emerging field with technological challenges. One major challenge is to minimise delivery catheter size to reduce vascular trauma, while maintaining features such as repositionability and retrievability. This study was designed as proof of concept of FOLDAVALVE, using a short-term ovine model. Methods and results: FOLDAVALVE is a fully repositionable and retrievable transcatheter aortic valve with a 14 Fr delivery system whose leaflets are excluded from the stent during crimping. A short-term ovine model (n=3) was used for transfemoral implantations at the Institut Mutualiste Montsouris in Paris. There was a smooth transition of the valve over the aortic arch followed by seamless delivery into the native ovine aortic position. Implantation was followed by repositioning, resheathing and retrieval, then implantation of a fresh prosthesis in the same animal. Transoesophageal echocardiography and fluoroscopy were used to monitor the delivery and implantation processes and to demonstrate valve functionality. Animal sacrifice and direct visualisation after explant confirmed excellent final position. Conclusions: FOLDAVALVE was successfully implanted in the aortic position of an ovine model. FOLDAVALVE is a promising technology which has been shown to be feasible in this preclinical TAVI study.

Transcatheter aortic valve implantation is a novel treatment for severe aortic valve stenosis. Due to the recent use of this technology and the procedural variability, there is very little data that quantify the hemodynamic consequences of variations in valve placement. Changes in aortic wall stresses and fluid retention in the sinuses of Valsalva can have a significant effect on the clinical response a patient has to the procedure. By comprehensively characterizing complex flow in the sinuses of Valsalva using digital particle image velocimetry and an advanced heart-flow simulator, various positions of a deployed transcatheter valve with respect to a bioprosthetic aortic valve (valve-in-valve) were tested in vitro. Displacements of the transcatheter valve were axial and directed below the simulated native valve annulus. It was determined that for both blood residence time and aortic Reynolds stresses, it is optimal to have the annulus of the transcatheter valve deployed as close to the aortic valve annulus as possible. Copyright © 2014 by the American Society for Artificial Internal.

In this final portion of an extensive review of heart valve engineering, we focus on the computational methods and experimental studies related to heart valves. The discussion begins with a thorough review of computational modeling and the governing equations of fluid and structural interaction. We then move onto multiscale and disease specific modeling. Finally, advanced methods related to in vitro testing of the heart valves are reviewed. This section of the review series is intended to illustrate application of computational methods and experimental studies and their interrelation for studying heart valves.