Pathophysiologic Observations and Histopathologic Recognition of the Portal Hyperperfusion or Small-for-Size Syndrome

Abstract

In an attempt to more completely define the histopathologic features of the portal vein hyperperfusion or small-for-size syndrome (PHP/SFSS), we strictly identified 5 PHP/SFSS cases among 39 (5/39; 13%) adult living donor liver transplants (ALDLT) completed between 11/01 and 09/03. Living donor segments consisting of 3 right lobes, 1 left lobe, and 1 left lateral segment, with a mean allograft-to-recipient weight ratio (GRWR) of 1.0 +/- 0.3 (range 0.6 to 1.4), were transplanted without complications, initially, into 6 relatively healthy 25 to 63-year-old recipients. However, all recipients developed otherwise unexplained jaundice, coagulopathy, and ascites within 5 days after transplantation. Examination of sequential posttransplant biopsies and 3 failed allografts with clinicopathologic correlation was used in an attempt to reconstruct the sequence of events. Early findings included: (1) portal hyperperfusion resulting in portal vein and periportal sinusoidal endothelial denudation and focal hemorrhage into the portal tract connective tissue, which dissected into the periportal hepatic parenchyma when severe; and (2) poor hepatic arterial flow and vasospasm, which in severe cases, led to functional dearterialization, ischemic cholangitis, and parenchymal infarcts. Late sequelae in grafts surviving the initial events included small portal vein branch thrombosis with occasional luminal obliteration or recanalization, nodular regenerative hyperplasia, and biliary strictures. These findings suggest that portal hyperperfusion, venous pathology, and the arterial buffer response importantly contribute to early and late clinical and histopathologic manifestations of the small-for-size syndrome.

Triple-phase computed tomography and intraoperative flow measurements improve the management of portosystemic shunts during liver transplantation

“…In contrast, in our 7 patients with PV flow Ͼ1 L/minute, shunt ligation was avoided, to prevent excessive PV flow that could impair hepatic artery flow via the hepatic artery buffer response. [16][17][18] The importance of the anatomic details offered by triple-phase CT with vascular reconstruction, coupled with the hemodynamic flow data, was highlighted when our first patient, who had a postreperfusion portal flow of 720 cc/minute, developed PV thrombosis posttransplantation.…”

Initial Poor Graft Dysfunction and Primary Graft Non-Function After Orthotopic Liver Transplantation

“…The histopathologic features of SFSS had been summarized by Demetris et al (Demetris et al, 2006). The portal vein and sinusoidal injury could be divided into early, intermediate, and late changes.…”

“…The ductular reaction consisted of portal tract expansion because of an increase of ductal profiles at the interface zone accompanied by acute neutrophilic periductular inflammation. Based on the above pathological manifestations, Demetris et al proposed the following sequence of SFSS (Demetris et al, 2006). First, portal venous hyperperfusion causes portal vein and sinusoidal endothelial cell injury which leads to intraparenchymal dissecting hemorrhage in severe cases.…”

“…Last, remnants of portal vein pathology often cause organizing mural thrombi or thickening in large branches portal vein branches and partial or complete luminal obliteration or recanalization in small portal vein branches. However, the histopathologic and pathophysiologic manifestations of SFSS have not been depended completely on peripheral core needle biopsies (Demetris et al, 2006). Under the examination of peripheral core needle biopsies, affected grafts most commonly show the following triad: centrilobular hepatocanalicular cholestasis, centrilobular hepatocyte microvesicular steatosis, and a ductular reaction at the interface zone.…”

Splenectomy improves survival by increasing arterial blood supply in a rat model of reduced-size liver

“…With the increasing practice of living-donor liver transplantation and the enlargement of the resectable liver mass, the small-for-size syndrome has emerged as an important clinical problem [8]. The ongoing debate on the causes of the small-for-size syndrome mainly focuses on portal hyperperfusion with high intravascular shear stress [9][10][11]. To avoid liver failure by portal hyperperfusion, techniques for reduction of portal inflow, such as portal-caval and mesocaval shunts, splenic artery ligation, and splenectomy have been established [12][13][14].…”