The hemocompatibility of standard surgical treatment of carotid artery disease through the insertion of metallic stents is investigated by means of radio wave dielectric spectroscopy technique that allows the measurements of the electrical parameters of the red blood cell membrane. Our measurements suggest that both the membrane permittivity and the membrane conductivity, which characterize the overall electrical behavior of the cell membrane, undergo an appreciable alteration of their standard values as a consequence of the stent insertion. These alterations persist over long period of time, up to 4 weeks. Even if these effects could not cause any evident damage at physiological or clinical level to the patient, the presence of a host response to the stent implant suggests that a full hemocompatibility has not yet reached, and a word of caution is necessary.