Addressing the Organ Shortage, Increasing Transplant Longevity, and Enabling Minimally Invasive Kidney Transplantation: Ex Vivo Validation of a Kidney Anastomosis Facilitation and Cooling Device
- Transplantation: Clinical - Pretransplant Assessment and Living Donors
November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
- 2002 Transplantation: Clinical
- Hansen, Keith S., University of California San Francisco, San Francisco, California, United States
- Gardner, James Morgan, University of California San Francisco, San Francisco, California, United States
Kidneys are particularly susceptible to anoxic damage and ischemia due to their aerobic metabolism. Hypothermia protects against anoxia by reducing the energy dependent metabolic activities. The warming of a donor kidney during the vascular anastomosis of a transplant i.e., second warm-ischemia time (SWIT), is independently associated with higher rates of delayed graft function, premature graft failure, and the discard of high-risk kidneys. SWIT is protracted in patients with complex anatomy, obesity, and in minimally invasive transplantation. Elimination of SWIT via intra-operative thermal regulation can increase the donor pool and proffer significant cost-savings.
ASTS surgeons (n=185) and transplant nephrologists were surveyed to determine the needs-criteria for a device. A prototype applied to the kidney immediately prior to anastomosis was built using stretchable hydrogel and phase-change gel. Adult porcine kidneys were used to test the device in a validated retroperitoneal-model placed within a water bath at 37oC (98.6oF). Core temperatures were monitored using implanted probes at 30 second intervals. Time to reach the maximum ischemic threshold of necrosis (15oC, 59oF) was compared to an ice + gauze control.
The needs-criteria for the device were addressed with a retraction handle, no tubing, a low profile, and a flexible material to accommodate variable kidney sizes. The device-covered kidneys (n=3) did not reach the ischemic threshold at the 60-minute cutoff and remained below 6oC compared with the ice + gauze covered control kidneys (17±1.8 minutes, n=3, p <0.001).
A breakthrough designated medical device to facilitate the vascular anastomosis and eliminate SWIT was successfully developed. Device-covered kidneys remained well below the ischemic threshold of necrosis for a duration exceeding 95% of vascular anastomoses. Use of this device will enhance the surgical workflow and enable minimally-invasive transplantation and has the potential to significantly impact rates of delayed graft function, organ longevity, and organ acceptance practices.