Scintigraphic evaluation of the viability of cold-preserved kidneys before transplantation.

Renal microcirculation studies utilizing microspheres can provide a highly reliable index of the viability of preserved kidneys. We describe a noninvasive method that permits subsequent transplantation of each tested kidney. Fresh canine kidneys were removed and perfused with either Collins' solution or Collins' solution with 5 mg/l of trifluoperazine (TFP), and preserved at 4 degrees to 6 degrees C in their respective perfusates for 5, 24, 48, or 72 hr. At the end of each period, the preserved kidney was perfused with 50,000 Tc-99m-labeled microspheres. Uniform cortical activity occurred in all kidneys preserved for 5 hr, with moderate decreases in cortical activity at 24 hr. Kidneys perfused with Collins' solution showed progressively decreasing cortical flow with sparse cortical activity after 72 hr. In kidneys perfused with Collins' solution containing TFP, however, cortical flow remained relatively well preserved at 48 and 72 hr. Direct correlation between viability of the cortical microcirculation and the capacity of the corresponding kidney to sustain life upon retransplantation into the original host was observed.