To find whether the liver can be procured after exclusive aortic perfusion, three organ perfusion models were used in three groups of donor rats. Group 1 underwent liver wash-out via the portal vein; in group 2, the kidneys alone were perfused via the aorta; and group 3 underwent simultaneous aortic perfusion of liver and kidneys. All perfusion flow rates in the three groups were adjusted to physiological values. Harvested organs were transplanted and recipient animals were killed 4 h after transplantation to study liver and kidney viability by using intracellular ATP measurement. Liver ATP was lower (P < 0.005) in the portal perfusion group (group 1: 1.396 +/- 0.412) than in the aortic perfusion group (group 3: 2.181 +/- 0.061). Kidney ATP was comparable in groups 2 and 3:1.066 +/- 0.09 vs 1.059 +/- 0.273 (mumol/g) tissue). Liver cooling was quicker with portal perfusion than with the aortic flush (20 degrees C in 20 s vs 15 degrees C in 60 s). Aortic perfusion at a physiologic flow rate has no detrimental effect on renal viability studied by intracellular ATP measurement. We conclude that liver cooling via the aortic route only is a good alternative to portal perfusion and seems to give good preservation. Application of this observation to emergency procurement in humans is still the subject of controversy.