First ex vivo and preliminary sheep model results of the new TRIBIO aortic valve bioprosthesis in small aortic annuli.

Objectives: Small aortic annuli are challenging in aortic valve replacement. Prosthesis-patient mismatch, accompanied by high transvalvular gradients and small orifice area, is an often faced problem impairing postoperative outcome. The new TRIBIO bioprosthesis aims to enable enhanced haemodynamics, being increasingly important with decreasing annular size. This study compares ex vivo hydrodynamics of TRIBIO with 2 established bioprostheses in small annuli at different stroke volumes, simulating 'rest' and 'exercise', and evaluates haemodynamics of TRIBIO in a sheep model.

Methods: Ex vivo: Porcine aortic roots were hardened with glutaraldehyde, approaching the stiffness of decalcified roots. Each bioprosthesis (TRIBIO, Trifecta™, Perimount® Magna Ease), size 19 mm, was implanted in each aortic root and inserted into a pulse duplicator, determining hydrodynamics and geometric orifice area at different stroke volumes (74, 90, 104 ml). Sheep model: Postoperative transvalvular gradients were assessed after implantation of 19 mm TRIBIO in aortic position.

Results: Ex vivo: Mean transvalvular gradients were lowest in TRIBIO (7.3, 8.7, 10.2 mmHg at 74, 90, 104 ml) with significant difference to Perimount® Magna Ease. Geometric orifice area in TRIBIO was 2.7 cm2 and significantly larger compared to Perimount® Magna Ease and Trifecta™. Opening of TRIBIO was uniform and apparently complete, whereas leaflet's outward movement was restricted particularly in Perimount® Magna Ease. Sheep model: TRIBIO presented with low transvalvular gradients (δpmean 4.1 ± 2 mmHg, δpmax 7.8 ± 4.6 mmHg), unimpaired leaflet motion and no central or paravalvular leakage.

Conclusions: Ex vivo, the TRIBIO achieved superior hydrodynamics compared to latest generation bioprostheses. These excellent data are supported by very low transvalvular gradients in a preliminary sheep model.