Continuous or intermittent vascular clamping during hemihepatectomy in pigs: hyaluronic acid kinetics in the assessment of early microvascular liver damage.

Objective: To assess the uptake of hyaluronic acid (HA) as a marker of microvascular damage in a model of hemihepatectomy in pigs having continuous or intermittent vascular inflow occlusion.
Design: Prospective, animal study.
Setting: Laboratory for experimental surgery, University hospital, The Netherlands.
Interventions: Total liver ischaemia was achieved during 90 minutes by continuous (n = 5) or intermittent (n = 5) occlusion of the portal vein and hepatic artery followed by 120 minutes of reperfusion. In a second series of pigs (n = 8) a left hemihepatectomy was added to the protocol.
Main Outcome Measures: Uptake of exogenous HA was assessed before ischaemia and after 120 minutes of reperfusion, together with the galactose elimination capacity. Plasma activities of aspartate aminotransferase (AST), alanine amino transferase, and lactate dehydrogenase were measured and specimens of liver were obtained for histopathological examination.
Results: HA uptake was slightly reduced after reperfusion in unresected livers compared with uptake before ischaemia. After hemihepatectomy HA uptake after reperfusion was significantly reduced after both continuous and intermittent occlusion, but more HA was taken up after continuous occlusion (p = 0.02). Release of AST after reperfusion was increased only after hemihepatectomy.
Conclusions: Microvascular damage, as assessed by HA uptake capacity, significantly contributed to normothermic ischaemia and reperfusion injury in porcine liver. Vascular inflow occlusion during 90 minutes in combination with hemihepatectomy resulted in less liver damage when vascular occlusion was continuous rather than intermittent.