Effects of hepatovenous back flow on ischemic- reperfusion injuries in liver resections with the pringle maneuver

BACKGROUND: Experimental findings have demonstrated a beneficial role of retrograde blood flow from hepatic veins that takes place during the Pringle maneuver in liver resections. The cytoprotective effect of hepatovenous back-perfusion has not been evaluated in humans. A randomized prospective study was designed to compare the response of liver cells to ischemic-reperfusion injury during the application of two different ischemic procedures: inflow versus inflow plus outflow vascular occlusion of the liver. STUDY DESIGN: Forty patients were randomly allocated to undergo liver resection using the continuous Pringle maneuver (n = 20) or inflow plus outflow vascular occlusion of the liver by selective hepatic vascular exclusion (n = 20). Liver function was assessed on postoperative days 1 to 6. Response of liver cells to I/R injury was evaluated by measuring interleukins IL-6 and IL-8 at 3, 12, 24, and 48 hours after reperfusion. Oxidative stress was assessed by measuring malondialdehyde levels. RESULTS: Both groups were comparable regarding ischemic time, operative time, and extent of liver resection. Patients in whom retrograde blood flow to the liver took place during the Pringle maneuver showed better liver function postoperatively and less severe hepatic I/R injuries compared with those undergoing liver resection using both inflow and outflow vascular occlusion. Oxidative stress was significantly lower in the Pringle maneuver group compared with the inflow plus outflow vascular occlusion group (mean +/- SD] malondialdehyde 8 +/- 2.1 micromol/L in the Pringle group versus 14.7 +/- 1.8 micromol/L in the selective hepatic vascular exclusion group 30 min after reperfusion, p < 0.01). CONCLUSIONS: Back perfusion via hepatic veins contributes to attenuation of I/R damage during the Pringle maneuver and should be preferred if possible during liver resection.