Experimental study on changes in energy metabolism and urine outflow with nonpulsatile low blood-flow perfusion in the canine kidney.

Objective: Renal artery perfusion is useful to prevent renal ischemic injury during thoracoabdominal aortic aneurysm repair, and this study was designed to clarify the relationship between the perfusion flow rate and the renal function.

Methods: Canine left renal arteries were perfused at selective low flow rates (10% of native flow in Group I, 25% in Group II, and 50% in Group III) using a roller pump for 2 h, and thereafter reperfused with native flow for 2 h. At the end of perfusion and reperfusion, the energy metabolites were measured. The urinary output was measured for 30 min during selective perfusion and reperfusion. Thus, the renal function was evaluated using energy metabolites and urine outflow.

Results: Adenosine triphosphate levels decreased significantly after perfusion in all groups and were recovered after reperfusion in Group II and in Group III. Inorganic phosphate and lactic acid levels increased after perfusion in Group I and in Group II and decreased after reperfusion. Changes in the perfusion pressure and in the urine outflow, and histologic findings were found to be correlated with the changes in energy metabolite levels.

Conclusions: Renal function was impaired depending on the degree of low perfusion flow and the function was restored after reperfusion at a flow rate of 25% or more of native flow.