The Outlet Orifice Diameter of Surgical Bioprosthetic Aortic Stented Valves Is Predominantly Much Smaller Than the Inlet Orifice Diameter 

The authors measured inlet and outlet orifice diameters and flow channel height of eight surgical bioprosthetic aortic stented valve models using an optical method. They demonstrated that in most valves (89 percent) the outlet orifice diameter is smaller than the inlet, resulting in a converging flow channel, while one model showed cylindrical geometry and another a diverging shape. Porcine valves exhibited higher gradient multipliers than bovine valves, with the Medtronic Avalus demonstrating the most favorable hemodynamic profile. The ratio between inlet and outlet diameters was consistent within each model type. The authors conclude that the outlet diameter is often the smallest and, therefore, hemodynamically most relevant dimension. They further emphasize that information on valve metrics is incomplete, scarce, and confusing, highlighting the need for more transparent and accessible reporting by manufacturers.