The effects of arterial pressure during normothermic kidney perfusion

Abstract Background Ex vivo normothermic perfusion (EVNP) can reverse some of the detrimental effects of ischemic injury. However, in kidneys with warm and cold ischemic injury the optimal perfusion pressure remains undetermined. The aim of this study was to evaluate the effects of two different arterial pressures during EVNP. Methods Porcine kidneys underwent static cold storage for 23 h followed by 1 h of EVNP using leukocyte depleted blood at a mean arterial pressure of either 55 or 75 mm Hg. After this, kidneys were reperfused for 3 h to assess renal function and injury. This was compared with a control group that underwent 24 h cold storage. Results During EVNP, kidneys perfused at 75 mm Hg had a higher renal blood flow, increased oxygen consumption (median 59.9 mL/min/g (range 30.1–78.6] versus 31.8 [8.2–53.8] mL/min/g; P  = 0.026), and produced more urine ( P  = 0.002) than kidneys perfused at 55 mm Hg. During ex vivo reperfusion, renal blood flow was significantly higher in the 75 mm Hg and 55 mm Hg groups compared with the control (area under the curve median 75 mm Hg 462 [228–745], 55 mm Hg 454 [254–923] versus control 262 [215–442] mL/min/100g.h; P  = 0.040). There was a significant loss of renal function and increase in tubular injury in the 55 mm Hg group kidneys ( P  = 0.001, 0.007). Levels of endothelin 1 were significantly reduced in the 75 mm Hg group ( P  = 0.026). Conclusions A mean arterial pressure of 75 mm Hg during EVNP resulted in less tubular damage and less endothelial injury during ex vivo reperfusion compared with kidneys perfused at 55 mm Hg.