A pressure sensor for being introduced into the circulatory system of a human being, wherein the pressure sensor is a passive sensor configured to be wirelessly read out by a reading system placed outside the human being, wherein the pressure sensor further comprises a casing , the casing comprising a diffusion blocking layer covering at least a part of the casing and configured to maintain a predetermined pressure within the casing, wherein the pressure sensor further comprises a magneto-mechanical oscillator, the magneto-mechanical oscillator comprising a magnetic object providing a permanent magnetic moment within the casing, wherein the magneto-mechanical oscillator is configured to transduce an external magnetic or electromagnetic excitation field into a mechanical oscillation of the magnetic object, wherein at least a part of the casing is flexible for allowing transducing external pressure changes into changes of the mechanical oscillation of the magnetic object, wherein the magnetic object is arranged within the casing such that it is rotatable out of an equilibrium orientation if the external magnetic or electromagnetic excitation field is acting on the magnetic object, wherein the pressure sensor further comprises a restoring torque unit comprising a further magnetic object for generating a magnetic field at the position of the magnetic object such that it provides the restoring torque, wherein the restoring torque unit is adapted to provide a restoring torque to force the magnetic object back into the equilibrium orientation if the external magnetic or electromagnetic excitation field has rotated the magnetic object out of the equilibrium orientation, in order to allow for the mechanical oscillation of the magnetic object with a resonance frequency, wherein the pressure sensor is configured such that the external pressure changes are transduced into changes of the resonance frequency. wherein the pressure sensor is a passive sensor configured to be wirelessly read out by a reading system placed outside the human being, wherein the pressure sensor further comprises a casing , the casing comprising a diffusion blocking layer covering at least a part of the casing and configured to maintain a predetermined pressure within the casing, wherein the pressure sensor further comprises a magneto-mechanical oscillator, the magneto-mechanical oscillator comprising a magnetic object providing a permanent magnetic moment within the casing, wherein the magneto-mechanical oscillator is configured to transduce an external magnetic or electromagnetic excitation field into a mechanical oscillation of the magnetic object, wherein at least a part of the casing is flexible for allowing transducing external pressure changes into changes of the mechanical oscillation of the magnetic object, wherein the magnetic object is arranged within the casing such that it is rotatable out of an equilibrium orientation if the external magnetic or electromagnetic excitation field is acting on the magnetic object, wherein the pressure sensor further comprises a restoring torque unit comprising a further magnetic object for generating a magnetic field at the position of the magnetic object such that it provides the restoring torque, wherein the restoring torque unit is adapted to provide a restoring torque to force the magnetic object back into the equilibrium orientation if the external magnetic or electromagnetic excitation field has rotated the magnetic object out of the equilibrium orientation, in order to allow for the mechanical oscillation of the magnetic object with a resonance frequency, wherein the pressure sensor is configured such that the external pressure changes are transduced into changes of the resonance frequency. <EOS>