Preliminary Results of Hepatic Blood Flow Modulation in an Experimental Model of Hepatectomy – Implications for Hepatic Artery Buffer Response Modulation

Abstract

Introduction: Portal hyperperfusion of the remnant liver has been implicated in post hepatectomy liver failure (PHLF) following major hepatectomy by inducing arterial vasoconstriction, also called Hepatic Artery Buffer Response (HABR). We aimed to compare the effect of a selective A2Aadenosine receptor agonist Regadenoson to a porto-caval (P-C) shunt in an experimental model of hepatectomy in piglets on hepatic blood flow modulation. Methods: A cohort study with cross-over design of serial doppler measurements in landrace pigs weighing 25-30 Kg was performed; all subjects underwent laparotomy and baseline measurements were taken. Thereafter extended left hepatectomy with P-C shunt was performed and measurements were repeated. Finally, the P-C shunt was occluded and all animals were administered intra-arterially 400mcg of regadenoson, prior repeating measurements. Results: The baseline portal vein and hepatic artery flow were 28.5 ± 7.47 ml/sec and 118.66 ± 19.28 ml/sec respectively. After hepatectomy a significant increase of the portal vein flow by 91.8% while the hepatic artery flow increase only by 26.4%, signifying activation of the HABR. Opening of the P-C shunt decreased the portal vein flow by 24.69% and a more pronounced decrease of hepatic artery flow (34.22%). After occlusion of the portocaval shunt and administration of regadenoson there was a minor decrease of the portal flow by 13.71% while there was a significant drop of the hepatic artery flow by 55.33%, thus more effectively decreasing arterial vasoconstriction (p<0.005). Conclusion: Regadenoson can more effectively decrease hepatic artery flow than PC shunt, thus signifying a potential role in the management of PHLF.