Remote Ischemic Preconditioning Decreases the Magnitude of Hepatic Ischemia-Reperfusion Injury on a Swine Model of Supraceliac Aortic Cross-Clamping

Abstract

Temporary hepatic ischemia is inevitable during open aortic surgery when supraceliac clamping is necessary, as in thoracoabdominal or pararenal aneurysms. Remote ischemic preconditioning (RIPC) has been described as a potential protective means against ischemia-reperfusion injury (IRI) in various tissues including the liver. The aim of this experimental study was to detect the effect of RIPC on liver IRI in a model of supraceliac aortic cross-clamping. An animal study was performed. Four groups of 6 swines each were examined: the control (sham) group, the ischemia-reperfusion (IR) group, and 2 remote ischemic preconditioning groups (RIPC I and RIPC II group). In the IR group, the animals underwent a complete cessation of the splanchnic arterial circulation for 30min by a concomitant occlusion of the supraceliac and the infrarenal aorta. In the RIPC groups, a remote preconditioning was applied before the splanchnic ischemia. This consisted of a temporary occlusion of the infrarenal aorta for 15min followed by 15min of reperfusion (RIPC I group), and 3 cycles of 5min similar ischemia, followed by 5min of reperfusion each (RIPC II group). All animals were followed for 24hr after the ischemia (reperfusion period). The liver ischemia-reperfusion injury was assessed by examining specific serum biomarkers indicating the magnitude of metabolic injury from selective blood samples of the hepatic circulation. In particular, the following parameters were examined: C-reactive protein, interleukin 6, tumor necrosis factor a, ferritin, and L-arginine. All parameters were affected in the IR group as compared to the sham group. Both RIPC groups developed a less serious change as compared to the IR group, in all examined parameters. In an animal study of splanchnic ischemia produced in a way to this produced during a supraceliac aortic aneurysm open repair, the remote ischemic preconditioning seemed to attenuate the effect of hepatic ischemia-reperfusion injury. Remote ischemic preconditioning produced with short bouts of ischemia of the lower body by temporary clamping of the infrarenal aorta might be used as a means of decreasing the detrimental effects of hepatic ischemia-reperfusion injury after supraceliac aortic cross-clamping. This was found in a swine model of suprarenal AAA open repair by studying the variance of certain biological biomarkers in selective blood samples retrieved from the hepatic vein.