We investigate the Rotor-Stator Interaction in a pump-turbine reduced scale model by considering fluid-structure coupling. The pressure fluctuations amplitude in the rotor-stator vaneless gap has generally been shown to increase linearly with the operating specific energy, subjecting the pump-turbines components to high stresses at high head operations. However, the present paper shows that the guide vanes vibratory properties may have a strong influence on the amplitude of the pressure fluctuations which are due to the Rotor-Stator Interaction. Thus, their amplitude may locally drop by 50% close to guide vanes reaching resonance.