Comparison of prolonged warm and cold ischemia on the solitary kidney during partial nephrectomy in a rabbit model

The aim of this study was to investigate the patterns of renal function recovery during partial nephrectomy (PN) on an experimental solitary kidney rabbit model and establish the upper tolerable time limits of applied ischemia. Forty-eight New Zealand rabbits underwent an open right nephrectomy and after 30 days, the animals were clustered into five groups (A, B, C, D, E). The first four groups received an open left PN, under different types of ischemia. Groups A (n = 8) and B (n = 10) were subjected to 90 and 60 min of warm ischemia (WI), respectively, while groups C (n = 10) and D (n = 10) received 90 and 120 min of cold ischemia (CI) with ice-slush cooling. Group E (n = 10) served as sham group. Serum determinations of creatinine (SCr) and BUN were recorded preoperatively and on postoperative days (POD) 1, 3, 6 and 15. The animals were euthanized and the remaining kidneys were harvested and evaluated microscopically. The type and duration of ischemia were statistically significant parameters (P < 0.001). Groups B, C and D exhibited a similar pattern of recovery from trial initiation to the 15th POD (P = 0.788 and P = 0.068, respectively). Group A was extremely differentiated, with 100% mortality caused by uremia. The microscopic findings were consistent to the serum biochemistry. In our solitary kidney rabbit model, the upper limits of tolerable WI seem to be set on 60 min. CI can safely preserve the model's renal function--even up to 120 min.