Improving kidney transplant outcomes using intraoperative thermal regulation

Abstract

Kidney transplantation remains the best treatment for end-stage kidney disease. The second warm ischaemic time (SWIT) is a major determinant of kidney transplant outcomes. SWIT refers to the rewarming phase during transplantation where the kidney is removed from static cold storage of 1°C-4°C during implantation into the recipient. SWIT usually ranges between 20-70 minutes, depending on the vessel count, surgeon experience, and anatomical differences. In this process, the kidney is exposed to the 37°C environment of the patient’s body temperature and begins to rewarm. Once the kidney reaches 15°C, it experiences warm ischaemic injury due to a loss of blood supply of the organ before anastomoses and reperfusion. This warm ischaemia can result in delayed graft function (DGF) and graft failure. DGF is an important early complication of kidney transplantation and is most commonly defined as the need for dialysis within the first-week post-transplantation. DGF is an important correlate of ischaemia-reperfusion injury (IRI). It is influenced significantly by the SWIT period, with a positive correlation between an extended SWIT period and ischaemic injury to the donor organ. Over 20% of kidneys in the U.S. experience DGF which inflicts a significant impact on graft survival while also presenting a substantial economic burden on the health system. Intraoperative organ thermal regulation may achieve a reduction in the SWIT period, or at the least reduce its impacts, potentially minimizing graft IRI and enhancing early graft function. However, there is no current effective, efficient, readily available, and acceptable system for achieving intraoperative thermal regulation in widespread use. This research aims to explore a thermally insulating kidney jacket as a viable option for intraoperative thermal regulation to examine the reduction in the impacts of the SWIT, the effects of thermal regulation on ischaemia-reperfusion injury, and the resultant kidney transplant outcomes.