Fig. 1
Definition of the pressure concepts in the context of aortic stenosis. Blood flows from left ventricular outflow tract (LVOT) into the ascending aorta (AAo) across the aortic valve that defines the geometric orifice area (GOA). When crossing the valve, a portion of the potential energy of the fluid is converted into kinetic energy, which is maximal at the effective orifice area (EOA) defining the peak pressure drop (ΔPpeak) where the ejection jet is narrowest. Downstream along the AAo the kinetic energy is transformed back to potential energy until a fully developed laminar flow profile where is the correct point to measure the net pressure drop (ΔPnet). The pressure recovery (ΔPrec) is the difference between ΔPpeak and ΔPnet. The pressure recovery distance (PRecDist) is defined as the distance necessary for the blood flow to go from the ΔPpeak to ΔPnet