Influence of Valsalva Sinus on Flow Field around the Aortic Valve and the Valve Characteristics (Quantitative Evaluation by Experiments in vitro Using a Realistic Model)

One of the well known cures for the annuloaortic ectasia is a vascular grafting surgery using a composite graft as an artificial ascending aorta and an artificial valve. Although, almost all conventional grafts do not have Valsalva sinus at the aortic root, the influence of omitting the Valsalva sinus have not yet been clarified. In order to understand the effect of the Valsalva sinuses at aortic root on the valve characteristics and flow field around the valve and furthermore the coronary blood flow, the authors have fabricated some realistic models of aortic valve using three-dimensional modeling machine, and have investigated the effect of the sinus existence by particle image velocimetry (PIV). As the result, the fluctuation of flow rate at coronary artery in the case of the straight wall model was larger than the Valsalva sinus model. The valve leaflets were pulled to the left ventricle, which could cause a diastolic regurgitant flow from the aorta into the left ventricle. The leaflet suction in the Valsalva sinus model was weaker than the straight wall model. Flow visualization results showed that vortex flow occurred in the Valsalva sinus due to jet flow through the valve leaflets during systole. At early diastole, flow into coronary artery around the Valsalva sinus was smoothly than the straight wall model. Consequently it was concluded from a standpoint of flow and valve characteristics that the Valsalva sinus had an important role for the aortic valve and the inlet of the coronary circulation.