Impact of graft size and commissural resuspension height on aortic valve competence in valve-sparing aortic replacement under physiological pressures.

Background: Valve competence in valve-sparing aortic root replacement has been described as being influenced by commissural height as well as graft size. The aim of this study was to investigate the impact of a gradual reduction of commissural height and graft diameter on aortic insufficiency under physiological conditions in an IN VITRO model.

Methods: Porcine aortic valves were reimplanted into a tubular graft and a native commissural height was obtained. Subsequently the height was reduced by 10 % and 20 %, respectively. To investigate the impact of graft size, a 30 % reduction of the prosthesis diameter was carried out in valves with both native and reduced commissural heights. All conditions were investigated under pulsatile flow simulation and static pressure exposure.

Results: Reduction of commissural height caused regurgitation at both 10 % and 20 % lower heights, which was more pronounced in grafts with 20 % reduction. Graft undersizing resulted in significant reflux, with regurgitation even occurring with valves in a native commissural position.

Conclusions: Valve competence is impaired both by the reduction of commissural height and by reduced graft size. In particular, reimplantation of aortic valves into undersized grafts promotes valve insufficiency even if commissural height is well adjusted.