Objective  To investigate the impact of two different surgical methods, orthotopic kidney transplantation and abdominal heterotopic kidney transplantation, on the surgical outcomes of pig-to-pig kidney transplantation and the short-term survival of recipient pigs after surgery.

Methods  Twenty-four Bama miniature pigs were divided into two groups, with 12 pigs in each group, and underwent orthotopic kidney transplantation and abdominal heterotopic kidney transplantation, respectively. The perioperative indicators of the recipient pigs, renal blood perfusion, the overall incidence rate of complications and survival rate were compared between the two surgical methods.

Results  The total surgical time, renal artery anastomosis time, renal vein anastomosis time, cold ischemia time and total ischemia time were all shorter in the abdominal heterotopic kidney transplantation group than in the orthotopic kidney transplantation group, with statistically significant differences (all P<0.05). The number of satisfactory renal perfusion cases was higher in the abdominal heterotopic kidney transplantation group than in the orthotopic kidney transplantation group (83% vs. 75%), but the difference was not statistically significant (P>0.05). The total incidence of postoperative complications was 33% in the heterotopic kidney transplantation group, with a survival rate of 92%, and the cause of death was rupture of the vascular anastomosis. The total incidence of postoperative complications was 50% in the orthotopic kidney transplantation group, with a survival rate of 83%, and the causes of death were renal vein thrombosis and renal artery thrombosis. There were no statistically significant differences in the total incidence of postoperative complications and survival rates between the two groups (all P>0.05).

Conclusions  Compared with orthotopic kidney transplantation, abdominal heterotopic kidney transplantation showes better surgical outcomes in pig-to-pig kidney transplantation and is more beneficial for the short-term survival of recipient pigs after surgery. This provides experience for improving the stability of pig-to-non-human primate kidney xenotransplantation models in the future.