Hemodynamic changes in the hepatic circulation after the modulation of the splenic circulation in an in vivo human experimental model

Abstract

Recent advances in liver surgery have highlighted the effects of the splenic circulation on the hepatic circulation with respect to the hepatic arterial buffer response (HABR). The aim of the present study was to investigate the actual hemodynamic effects of splenic artery embolization/ligation and splenectomy on the hepatic circulation in patients who underwent pancreaticoduodenectomy through in vivo experimental models. In vivo models of splenic artery embolization/ligation (only splenic artery clamping) and splenectomy (simultaneous clamping of both the splenic artery and the splenic vein) were created in 40 patients who underwent pancreaticoduodenectomy for various reasons. The portal venous flow velocity, the portal venous flow volume, the hepatic arterial flow velocity, and the hepatic arterial resistance index were measured with color Doppler ultrasonography. Clamping of the splenic artery induced an immediate and significant increase (16%) in the hepatic artery velocity (P < 0.001), and the portal venous flow also decreased significantly (10%, P 5 0.03). Fifteen minutes after the clamping of the splenic artery, the hepatic artery velocity remained significantly increased at the level of the initial clamping, and the portal venous flow significantly decreased (16%, P < 0.001). Clamping of the splenic vein, which was performed after the clamping of the splenic artery, resulted in an immediate and significant decrease (30%) in the portal venous flow (P < 0.001), but the hepatic arterial flow was not affected. Fifteen minutes after the clamping of the splenic vein, there was no change in the portal flow, which remained significantly lower (28%) than the flow in controls, whereas the hepatic arterial flow further significantly increased (31%, P < 0.001). In conclusion, our findings indicate that both splenic artery embolization/ligation and splenectomy are effective for increasing hepatic arterial flow and decreasing portal flow, with splenectomy providing a greater advantage. The HABR underlies these hemodynamic changes. Liver Transpl 20:116-121, 2014. V C 2013 AASLD.Received June 1, 2013; accepted September 13, 2013.Splenectomy has been performed for patients with liver cirrhosis not only to cure or relieve intractable gastroesophageal varices 1,2 but also to improve liver function before hepatectomy, 3,4 especially in Japan. The technical advances and deeper knowledge gained in the field of liver transplantation have highlighted another role of splenectomy in the regulation of the hepatic circulation via modifications of the splenic circulation. 5,6Abbreviations: HABR, hepatic arterial buffer response; SAS, splenic artery syndrome; SFSS, small-for-size syndrome.

Impact of imbalanced graft-to-spleen volume ratio on outcomes following living donor liver transplantation in an era when simultaneous splenectomy is not typically indicated

“…First, selecting a larger graft can increase GSVR. [30][31][32] Therefore, it should be reserved for only necessary cases. Second, SPX could prevent thrombocytopenia and improve graft function.…”

Vascular Remodeling of Visceral Arteries Following Interruption of the Splenic Artery During Liver Transplantation

“…It has been suggested that in these scenarios, vascular remodeling is driven by increased tangential shear stress over endothelial cells leading to increased expression of adhesion molecules, recruitment of inflammatory cells, and secretion of several mediators and cytokines that ultimately determine reshaping of the arterial wall and caliper measurement increases. After SA ligation, flow into the hepatic artery is increased as an effect of the interruption of the splenic siphon and of decreased portal vein flow . The flow is diverted also toward the LGA and, if the gastroduodenal artery has not been divided, toward the GEA, causing the hemodynamic changes determining vascular remodeling.…”

“…Although clinically different, portal hyperperfusion plays a pivotal role in both syndromes by determining vasoconstriction and disturbance of hepatic artery flow . SA occlusion has been shown to cause a modulation of portal vein flow and a concomitant increase of hepatic artery flow, and it has therefore been advocated as an effective procedure to prevent or treat both small‐for‐size syndrome and SA syndrome . In selected patients, the SA can be divided and used for arterial reconstruction during transplant operation if the hepatic artery and its branches are not suitable …”

“…(1) SA occlusion has been shown to cause a modulation of portal vein flow and a concomitant increase of hepatic artery flow, and it has therefore been advocated as an effective procedure to prevent or treat both small-for-size syndrome and SA syndrome. (2)(3)(4)(5) In selected patients, the SA can be divided and used for arterial reconstruction during transplant operation if the hepatic artery and its branches are not suitable. (6,7) SA dissection and ligation can be technically challenging in patients with severe portal hypertension and large peripancreatic varices, as it may cause significant bleeding or pancreatic injury.…”

Child-to-Adult Liver Transplantation With Donation After Cardiac Death Donors

“…The following report by Feng et al shown the advantage of splenectomy which could prevent the occurrence of SFSS by leading a decrease in the portal flow and PVP and a significant increase in the arterial flow. 15,16 Nevertheless, there is also considerable increase of surgical risk and infection for splenectomy. 17,18 On the other hand, recent studies suggest spleen plays an important role in regulating the immune system, metabolism, and endocrine function.…”