VISCERAL LIPID-PEROXIDATION OCCURS AT REPERFUSION AFTER SUPRACELIAC AORTIC CROSS-CLAMPING

Purpose: Recently, we have reported that lipid peroxidation specific to oxygen free radical-mediated injury increased immediately after reperfusion of human liver allografts. However, in the human liver transplantation setting it was impossible to disassociate the contributions to lipid peroxidation caused by the warm and cold ischemic phases from those caused by reperfusion. Therefore we now have studied lipid peroxidation at reperfusion after supraceliac aortic cross-clamping in patients with normal livers. Methods: Ethane, a noninvasive biomarker of lipid peroxidation, was measured in exhaled breath of patients before and during cross-clamping of the thoracic aorta and at sequential time intervals after visceral reperfusion. Results: Approximately a two-fold transient increase in the ethane level was observed at around 15 minutes after reperfusion in those patients whose aortas were cross-clamped for more than 18 minutes. Conclusions: These results indicate that free radical-mediated lipid peroxidation occurs at reperfusion of warm ischemic viscera in the clinical setting of aortic repair. This observation supports the hypothesis that substantial lipid peroxidation occurs when tissues are subjected to cold or warm ischemia followed by reperfusion.