Selective renal blood perfusion induces renal tubules injury in a porcine model

Objective: Extracorporeal circulation is routinely used in thoracoabdominal aortic aneurysm repair to preserve blood perfusion. Despite this protective measure, acute and chronic kidney disorders can develop. Therefore, the aim of this study was to establish a new large-animal model to assess the efficacy of selective renal perfusion (SRP) with extracorporeal circulation in a setting of thoracoabdominal aortic aneurysm repair. Methods: Eighteen pigs underwent a thoracolaparotomy, during with the aorta and renal arteries were exposed. The animals were divided into three cohorts of six pigs each: cohort I-control; cohort II-thoracic aortic clamping with distal aortic perfusion (DAP) using a roller pump; and cohort III-thoracic aortic clamping with DAP plus SRP. Kidney metabolism, kidney injury, and red blood cell damage were measured by oxygen extraction ratio (O2ER), neutrophil gelatinase-associated lipocalin, a marker for acute kidney damage, and serum free hemoglobin. Results: With normal mean arterial blood pressures, flow rates in the renal arteries during perfusion decreased to 75% (group II) with DAP and to 50% (group III) with SRP compared with the control animals (group I; P = .0279 for I vs II; P = .0002 for I vs III). Microcirculation, measured by microspheres, did not differ significantly among the groups. In contrast, O2ER (P = .0021 for I vs III) and neutrophil gelatinase-associated lipocalin (P = .0083 for I vs III) levels were significantly increased in group III, whereas free hemoglobin was increased in groups II and III (P = .0406 for I vs II; P = .0018 for I vs III). Conclusions: SRP with a roller pump induces kidney tubule injury. Thus, distal aortic and SRP in our model does not provide adequate kidney protection. Furthermore, the perfusion system provokes red blood cell damage with increased free hemoglobin. Hence, the SRP perfusion technique should be revised and tested.