An implantable cardiovascular pressure sensor comprising a rigid enclosure sealed by a flexible membrane; and an elongate compliant member comprising a piezoelectric material, the member having a width and a length greater than the width, and two ends separated by the length and two sides separated by the width; wherein the flexible membrane is coupled to the elongate compliant member to transfer external fluid pressure load to the elongate compliant member to cause deflection of the elongate compliant member in response to changes in the external fluid pressure; the pressure sensor further comprising a first acoustic wave device provided by the piezoelectric material of the elongate compliant member for sensing said deflection.