Protection From Second Warm Ischemic Injury Using a Thermal Barrier Bag in Kidney Transplantation

Background. Second warm ischemic injury during vascular anastomosis not only adversely affects immediate posttransplant function but also affects long-term patient and graft survival. We developed a pouch-type thermal barrier bag (TBB) composed of a transparent, biocompatible insulation material suitably designed for kidneys and conducted the first-in-human clinical trial. Methods. A living-donor nephrectomy was performed using a minimum skin incision procedure. After back table preparation, the kidney graft was placed inside the TBB and preserved during vascular anastomosis. The graft surface temperature was measured before and after vascular anastomosis using a noncontact infrared thermometer. After completion of the anastomosis, the TBB was removed from the transplanted kidney before graft reperfusion. Clinical data, including patient characteristics and perioperative variables, were collected. The primary endpoint was safety, which was assessed by evaluating adverse events. The secondary endpoints were the feasibility, tolerability, and efficacy of the TBB in kidney transplant recipients. Results. Ten living-donor kidney transplant recipients with a median age of 56 y (range, 39–69 y) were enrolled in this study. No serious adverse events related to the TBB were observed. The median second warm ischemic time was 31 (27–39) min, and the median graft surface temperature at the end of anastomosis was 16.1 °C (12.8–18.7 °C). Conclusions. TBB can maintain transplanted kidneys at a low temperature during vascular anastomosis, which contributes to the functional preservation of transplanted kidneys and stable transplant outcomes.