Ex vivo perfusion with anticoagulated blood decreases ischemia/reperfusion injury

Rat muscle flaps (cutaneous maximus) were subjected to 4 hours of room-temperature ischemia followed by 44 hours of cold (4 degrees C) ischemia before transplantation. Experimental flaps underwent a 15-minute ex vivo perfusion with heparinized-citrated blood between the warm and cold ischemic treatments; control flaps were not perfused. After 1 or 48 hours of recirculation, muscle dehydrogenase activity was found to be higher in the perfused flaps, indicating better muscle viability. Lipid peroxidation was lower in the perfused flaps, indicating a reduction in free radical generation. Histologic assessment revealed that perfused flaps underwent less injury than unperfused flaps. The findings of this study indicate that replacement of standing blood with anticoagulated blood, with the use of a brief ex vivo perfusion protocol, has a significant protective effect against ischemic injury. The experimental design mimics a realistic point of intervention and presents a paradigm for the clinical treatment of amputated extremities.