In this letter, we report a method to measure changes in a fluid pressure, flowing through a flexible pipeline, by means of a ring of magnetic microwire concentric to the pipeline. The detection is based on the modulated scattering of electromagnetic waves by the magnetoelastic ring. This modulation is driven by applying a low frequency bias magnetic field able to tune the magnetic permeability of the ferromagnetic microwire. Pressure detection, by means of magnetic permeability changes, is possible due to the magnetostrictive character of the sample. The experimental work developed has, also, allowed fluid pressure detection in a hydraulic circuit connected to ventricular assist system where a fluid with a viscosity close to blood flows.