Development of a Prolonged Warm Ex Vivo Perfusion Model for Kidneys Donated after Cardiac Death

Abstract

PURPOSE: Ex vivo perfusion of marginal kidney grafts offers the chance to expand the donor pool, but there is no current clinical standard for the prolonged warm perfusion of renal grafts. This exploratory pilot study seeks to identify a stable ex vivo kidney perfusion model that can support low intravascular resistance and preserve histologic architecture in a porcine donation after cardiac death (DCD) model. METHODS: 15 kidneys were preserved in 1 of 3 settings: normothermic whole blood (NT-WB), normothermic Steen Solution™ (XVIVO Perfusion) with whole blood (NT-Steen/WB), or subnormothermic Steen Solution™ at 21°C (SNT-Steen). Kidneys were primarily assessed using hemodynamic parameters and histologic analysis. RESULTS: NT-WB perfusion resulted in high vascular resistance and glomerular necrosis. NT-Steen/WB and SNT-Steen resistance ranged between 0.18-0.45 mmHg/mL per minute and 0.25-0.53 mmHg/mL per minute, respectively, enabling stable perfusion for up to 24 hours. NT-Steen/WB demonstrated tubular and glomerular necrosis, while the histologic architecture of SNT-Steen was preserved with the exception of numerous proteinaceous casts. CONCLUSIONS: Our results suggest that ex vivo kidney perfusion with Steen Solution™ at 21°C supports low and stable vascular resistance and provides adequate histologic preservation during 24-hour perfusion.