Ischemic Preconditioning at a Distance in Liver Surgery

Overview

During hepatic transection, it exists a high risk of perioperative blood loss. The haemorrhage and its consequences (hypovolemia and blood transfusion) might impact the short and long term morbidity The vascular control by hepatic pedicle clamping (Pringle's maneuver) or total hepatic vascular exclusion, helps minimizing blood loss and leads to a more extensive hepatic resection. Side effects of vascular control result of ischemia-reperfusion injury (IRI) : these reperfusion lesions results of different mechanisms than those responsible for the ischemic one. IRI cause lesions and postoperative dysfunction of the remaining liver. Among strategies to reduce the adverse effects of IRI : ischaemic preconditioning (IPC) has been described. It can be either mechanical (intermittent hepatic pedicle clamping) or pharmacological (sevoflurane inhalation). Short intermittent vascular occlusions in a organ might produce a resistance to a longer ischaemic period. It is certainly a physiological organ adaptation to tissue hypoxemia, which has a therapeutic potential when targeted. During liver resection, ischaemic preconditioning is realised with periods of hepatic pedicle clamping and unclamping. It decrease morbidity and mortality and prevent postoperative hepatocellular insufficiency due to clamping and IRI at day 5. Ischaemic preconditioning may also be applied remotely. Indeed, it is shown that short ischaemic periods in a target organ can also have a protective effect on distant others. This mechanism involve three signalling pathways : neuronal , humoral and systemic pathways. In a previous randomized study, Kanoria and al, demonstrated that the remote ischaemic preconditioning group has shown significant lower rates of serum transaminases and higher liver clearance (spectrophotometry method) than the control group. A latest study, measuring postoperative prothrombin rates has shown improved liver recovery due to halogen agents such as sevoflurane.