Telemetric assessment of liver impedance: Evaluation of a device for the noninvasive diagnosis of acute rejection after experimental liver transplantation

Allograft rejection and its differentiation from other causes of organ dysf unction remains a diagnostic problem in liver transplant patients. Currentl y, acute rejection can be prevented only by a combination of diagnostic and therapeutic modalities. The diagnostic potential of a novel implantable te lemetric rejection monitoring device has been assessed on the basis of the noninvasive impedance analysis in normal and liver transplanted pigs. The e lectric impedance data were correlated with biochemical and histological pa rameters. Acute rejection was correctly predicted in n = 4, and correctly e xcluded in n = 32, biopsy-related impedance recordings (p = 0.004). A corre lation between impedance measurements and severity of histological findings r = 0.84; p = 0.0001) was confirmed. Only the biochemical parameters SGLDH and serum bilirubin revealed a comparable correlation. Impedance gradient analysis revealed evidence of a physiological relationsh ip between liver function and the electrical properties of the organ. Telem etric impedance analysis would appear a promising means of assessing acute rejection noninvasively.