An improved version of continuous pulse-wave velocity estimation uses 4D-Flow data with time-delay recovered from a faster formulation using FFT. The novelty also relies upon neglecting regressive time-delay zones, yielding stable and reliable results. Numerical simulations are shown to assess the method. We also present its application in patients with Familial Hypercholesterolemia and Fontan. Consistently with previous findings, adult controls have stiffer aortic walls compared to young controls. Also, Fontan patients appear with stiffer aortic arch than other subjects. More interestingly, all subjects show a softening in the aortic arch respect to the rest of the vessel.