A controllable double-cycle cryogenic device inducing hypothermia for laparoscopic orthotopic kidney transplantation in swine

BACKGROUND: It is necessity to maintain donor kidneys at a low temperature for laparoscopic orthotopic kidney transplantation (LOKT). We recently designed a controllable double-cycle cryogenic device (DCD) with a safer and more effective cooling setting. This study aimed to evaluate the safety and efficacy of this device in a swine model. METHODS: A total of 20 pigs were procured for this study. We performed LOKT on 8 pigs using the controllable DCD for hypothermia, on another 8 pigs using the silicon tube cage (STC) for hypothermia, and on 4 pigs as the control group with no hypothermia measures (NH). The LOKTs were performed in autotransplantation mode in which the right kidney vein and artery were end-to-end anastomosed to the left kidney vein and artery in all three groups. The perioperative data, graft temperatures, and surgical complications were recorded, and histological examinations of kidney specimens were performed. RESULTS: The average surface temperature in the DCD group (5±3.5 °C) was significantly lower than that in the STC (10±5.5 °C) and NH (28±3.0 °C) groups. In the DCD and STC groups, the temperature between the cooling setting and the adjacent peritoneum was 30±3.0 and 12±5.0 °C, respectively. All pigs survived for 7 days in the DCD group. In the STC group, 2 pigs died from liver lesions and other causes. A single pig had diabetes insipidus. No pigs survived for 7 days in the NH group. The specimens from pigs immediately after revascularization and from the surviving pigs on day 7 following transplantation showed that the morphology of the glomerular and renal tubules was largely normal in the DCD and STC groups. However, in the NH group, there was minimal interstitial and tubular oedema, and endothelial cell swelling occurred in some specimens immediately after revascularization. Pathological examination of the harvested graft specimens showed severe acute tubular necrosis in the NH group. CONCLUSIONS: The newly designed controllable DCD can achieve the goal of cooling the kidney and warming the patient and may be a reliable, effective, inexpensive, and practical hypothermic maintenance system for LOKT in swine.