Hemodynamic Factors Affecting the Functioning of the Aortic Valve

Early stages of aortic valve disease involve a subtle increase in leaflet stiffness which affects valve performance seen particularly in the opening and closing of the valve. In this study, a pulse duplicator which recreates physiologic flow waveforms was used to evaluate how changes in experimental conditions such as downstream resistance and flow rate affect the opening and closing patterns of valves with varying stiffness. A photographic technique which allowed for analysis of valve leaflet motion revealed various trends in relation to the flow, resistance, and stiffness of the valves. Increased flow and resistance lead towards shorter opening and closing times for the valves, while increased valve stiffness demonstrated an increase in the opening and closing times of the valves. Pressure drops across the aortic valves decreased during the closing cycles as the area decreased, and increased during the opening cycles as the area increased. These results indicate that hemodynamic factors influence the severity of the disease as demonstrated by the trends observed during the opening and closing cycles of the valve.