Perfusate lactate dehydrogenase level and intrarenal resistance could not be adequate markers of perfusion quality during isolated kidney perfusion

The main goal of this work was to study the influence of perfusion pressure and flow waveform during kidney perfusion, and the relationship between re nal vascular resistance (RVR) and lactate dehydrogenase (LDH) concentration in the perfusate. Simultaneous constant pressure kidney perfusions were pe rformed with either pulsatile or continuous flow at either 30 or 80 mm Hg o f constant perfusion pressure. Mean flow, pressure, and RVR were displayed online during perfusion. Perfusate samples for LDH, creatine phosphatase ki nase (CPK), and alkaline phosphatase (AP) determinations were taken. At the end of the perfusion, 2 ml of Evans blue was injected into the circuit to obtain images of perfusate distribution, and the kidneys were weighed. Also , hematoxylin/eosine studies were performed, showing more Bowman's space an d tubular dilation in kidneys perfused with high pressure. We did not find differences in RVR between kidneys perfused at 30 and 80 mm Hg; nevertheles s, perfusate distribution was better in the 80 mm Hg perfusions. We did not find any correlation between enzyme release and RVR in kidneys perfused wi th different mean pressures. These findings suggest that vascular resistanc e and LDH concentration cannot be independently considered as adequate mark ers of perfusate distribution.