['This investigation sought to discern the accuracy of Doppler predictions of pressure drops in stenotic jets mimicking aortic coarctation (AC) across a broad spectrum of conditions, using an in vitro nonpulsatile flow model.', 'The model allowed for different AC diameter and length, different cardiac output, and different diameter of the aorta distal to the AC. For each study condition, pressure drops across a model of AC were measured both noninvasively using the simplified Bernoulli equation (SBE) and invasively using the instantaneous actual pressure gradient. We observed a good correlation of SBE-predicted and actual pressure gradients (slope = 0.929; r = 0.907, P < 0.0001) when AC diameter was small and the diameter of the aorta distal to the AC was large. However, we observed various degrees of overestimation by Doppler when mild AC was simulated (P = 0.0003), or when the diameter of the aorta distal to the coarctation was reduced (P < 0.0001). Increased AC length was associated with underestimation of actual pressure gradient by Doppler when AC diameter was small. Accounting for pressure recovery and viscous losses reduced the discrepancies between Doppler-predicted and actual pressure gradients in all study conditions (slope = 0.964; r = 0.989, P < 0.0001).'] Does pressure recovery explain doppler overestimation of invasive pressure gradient across segmental vascular stenosis?