Adult-to-adult live donor liver transplantation: a short-term clinicopathologic study

Pathologic Analysis of Right-Lobe Graft Failure in Adult-to-Adult Live Donor Liver Transplantation

Live donor adult liver transplantation (LDALT) utilizing right-lobe grafts is now acceptable as an alternative to cadaveric orthotopic liver transplantation (OLT). However, some LDALTs fail and require urgent OLT or result in recipient death. Our aim was to determine the basis of LDALT failure. Liver specimens from 49 LDALT recipients were evaluated and the findings correlated with clinical outcome. Ten patients (20.4%) had either early (< 1 month) or late (> 1 month) graft failure. Eight early failures, 7 of which occurred among our first 25 cases, were due to extensive liver parenchymal necrosis as a result of hepatic artery thrombosis (n=3), portal vein thrombosis (n= 1), hyperperfusion syndrome (n= 1), complete graft thrombosis (n= 1) with Factor V Leiden on a regimen of therapeutic heparin (n=1), sepsis and concomitant graft dysfunction with venous outflow tract injury (n=I), and venous outflow tract thrombosis and parenchymal thermal injury with sepsis (n=1). Preoperative, intraoperative, or postoperative severe vessel wall injury was evident in 6/8 early failures. TWo patients had late graft failure, 1 from recurrent hepatitis C and 1 with sepsis/multisystem organ failure. There were no significant differences in graft size, rejection episodes, or operative or ischemic times between patients with and without graft failure. In conclusion, LDALT failed in 10/49 (20%) of our patients, with 8/10 occurring within 1 month post-LDALT owing to vascular/thrombotic complications experienced during the early phase of our institutional experience. Perioperative vessel wall injury appeared to be a major factor in predicting early graft loss.

Massive ascites after living donor liver transplantation with a right lobe graft larger than 0.8% of the recipient's body weight

BACKGROUND

There are only limited data on post-transplant ascites unrelated to small-sized grafts in living donor liver transplantation (LDLT).

METHODS

The subjects were 59 adult patients who had received right lobe LDLT with a graft weight-to-recipient weight ratio (GRWR)>0.8%. Patients were divided into either Group 1 (n=14, massive ascites, defined as the production of ascitic fluid>1000 mL/d that lasted longer than 14 d after LDLT) or Group 2 (n=45, no development of massive ascites). Patients were followed for a median period of 3.0 yr (range, 0.5-7.5 yr).

RESULTS

Group 1 had both higher Model for End-Stage Liver Disease score and Child-Pugh score than Group 2. Portal venous flow volume just after reperfusion was significantly greater in Group 1 than Group 2 (307.8±268.8 vs. 176.2±75.0 mL/min/100 g graft weight, respectively; p<0.05). Post-transplant infectious complications including ascites infection developed more frequently within the first post-transplant month in Group 1. Massive ascites was significantly associated with early graft loss (p<0.05).

CONCLUSION

Post-transplant massive ascites associated with portal over-perfusion into the graft liver can develop in patients with a GRWR over 0.8%. Recipients with post-transplant massive ascites require careful management to prevent infection.

Pathophysiologic observations and histopathologic recognition of the portal hyperperfusion or small-for-size syndrome

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.

Excessive portal flow causes graft failure in extremely small-for-size liver transplantation in pigs

AIM

To evaluate the effects of a portocaval shunt on the decrease of excessive portal flow for the prevention of sinusoidal microcirculatory injury in extremely small-for-size liver transplantation in pigs.

METHODS

The right lateral lobe of pigs, i.e. the 25% of the liver, was transplanted orthotopically. The pigs were divided into two groups: graft without portocaval shunt (n = 11) and graft with portocaval shunt (n = 11). Survival rate, portal flow, hepatic arterial flow, and histological findings were investigated.

RESULTS

In the group without portocaval shunt, all pigs except one died of liver dysfunction within 24 h after transplantation. In the group with portocaval shunt, eight pigs survived for more than 4 d. The portal flow volumes before and after transplantation in the group without portocaval shunt were 118.2+/-26.9 mL/min/100 g liver tissue and 270.5+/-72.9 mL/min/100 g liver tissue, respectively. On the other hand, in the group with portocaval shunt, those volumes were 124.2+/-27.8 mL/min/100 g liver tissue and 42.7+/-32.3 mL/min/100 g liver tissue, respectively (P<0.01). As for histological findings in the group without portocaval shunt, destruction of the sinusoidal lining and bleeding in the peri-portal areas were observed after reperfusion, but these findings were not recognized in the group with portocaval shunt.

CONCLUSION

These results suggest that excessive portal flow is attributed to post transplant liver dysfunction after extreme small-for-size liver transplantation caused by sinusoidal microcirculatory injury.

Cadaveric full-size liver transplantation and the graft alternatives in adults: a comparative study from a single centre

BACKGROUND/AIMS

This study aims to compare the results of living donor (LDLT), cadaveric split (SLT) and domino (DO) liver transplantation which are currently available alternatives to the conventional cadaveric full-size liver transplantation (CAD).

METHODS

Immunologic, vascular and biliary complications (BC) were evaluated in 38 LDLT, 20 SLT, 17 DO and 38 CAD recipients.

RESULTS

The incidence of acute rejection (AR) was similar between groups, and between blood-related and blood-unrelated patients. AR was more severe in the SLT group according to the Banff scores (P=0.03, P<0.001, P<0.001). The evolution of AR was similar between the groups, in terms of development of chronic rejection. No venous complications occurred in the overall population. The rate of arterial thrombosis (10.5, 10, 0 and 3%, respectively) was statistically similar between groups. The rate of BC (26, 40, 12, and 8%, respectively) was higher in the partial grafts than in the whole grafts (P=0.006), but was not significantly different within each group. There was an association between the severity of preservation injury and occurrence of AR (P=0.01) and arterial thrombosis (P=0.016), but not BC. One- and 2-year graft and patient survival rates were similar between groups.

CONCLUSIONS

None of the graft types seemed to confer immunological advantage. BC remained problematic in the partial grafts, independently from ischemia time.

The Histologic Pattern of ???Biliary Tract Pathology??? Is Accurate for the Diagnosis of Biliary Complications

A histologic pattern comprising centrilobular cholestasis and portal changes including edema, predominantly neutrophil polymorph infiltration, cholangiolar proliferation, and cholangiolitis is well known to correspond to biliary obstruction. This pattern, referred as biliary tract pathology (BTP) in this text, remains unclear in terms of its clinical significance. We aimed to assess the incidence, timing, and diagnostic accuracy of BTP after liver transplantation. All 248 liver biopsies and clinical records, from 94 patients, including 30 living donor, 17 split, 15 domino, and 32 cadaveric full-size primary liver transplantation, were reviewed. BTP was diagnosed in 21% of biopsies from 31% of patients at a median of 28 days after transplantation (range, 5-763 days). When radiologic imaging of the biliary tree was taken as the gold standard, biopsy was found to have a sensitivity of 87% (95% confidence interval, 73%-100%) and a specificity of 87% (95% confidence interval, 80%-95%) for the diagnosis of biliary complications. An underlying clinical condition was found in 86% of cases, which included biliary complications (69%), arterial thrombosis (3%), sepsis (10%), and recurrent disease (3%). In 14% of cases, BTP remained unexplained. In conclusion, BTP after liver transplantation has clinical significance in most cases, with a particular emphasis for true biliary complications. This pattern must incite radiographic verification of the biliary tract.

Excessive portal flow causes graft nonfunction in small size liver transplantation: An experimental study in pigs

We investigated the effects of portocaval shunt (PCS) on excessive portal flow in producing sinusoidal microcirculatory injury in small-for-size liver transplants in pigs. The posterior segment of a whole liver (25%) was transplanted orthotopically. The pigs were divided two groups: group A, graft with PCS (n = 11), and group B, graft without PCS (n = 11). The PCS was a side-to-side anastomosis of the portal vein and the inferior vena cava. In group A, eight pigs survived for more than 4 days; all pigs except for one died of graft nonfunction within 24 hours in group B. The portal flow after reperfusion decreased in group A, but increased about three times greater in group B than that before the operation (P < .01). In group B, destruction of the sinusoidal lining and bleeding in the periportal areas were observed after reperfusion, findings that were not recognized in group A. These results suggest that graft nonfunction after small-for-size liver transplantation may be attributable to excessive portal flow producing sinusoidal microcirculatory injury.

Hepatocellular proliferation and changes in microarchitecture of right lobe allografts in adult transplant recipients

Imaging studies show complete restoration of liver volume in adult recipients of right lobe allografts within 2-3 weeks of living donor transplantation (LDLT). However, it is not known if this growth is associated with restoration of hepatic microarchitecture. We compared 21 biopsies without significant pathology from LDLT recipients with 23 biopsies from adult recipients of cadaveric donor liver transplantation (CDLT) performed within 3 months of transplantation. The difference in the number of portal tracts per cm was statistically significant (P < .0001) between CDLT (9.08 +/- 1.74) and LDLT recipients within 3 months (6.26 +/- 1.62), as well as after 3 months following transplantation (6.56 +/- 1.44). The coefficient of correlation between length of biopsy specimens and the number of portal tracts in these 3 groups was .94, .93, and .85, respectively. Proliferative activity demonstrated by immunohistochemical staining for MIB-1 was seen predominantly in hepatocytes in both groups; bile ducts only occasionally stained positive. The difference between labeling indices of hepatocytes was statistically significant (P = .00056) between CDLT and LDLT recipients within 3 months of transplantation (.82 +/- .63 and 4.53 +/- 3.72), and between LDLT recipients within 3 weeks and after 3 weeks of transplantation (5.97 +/- 3.78 and 1.80 +/- 1.37, P = .0074). In conclusion, restoration of liver volume following LDLT occurs by proliferation of hepatocytes in the immediate posttransplant period. There is a decrease in number of portal tracts in these volume-restored allografts. Volume restoration is therefore, not accompanied by restoration of hepatic microarchitecture.

Excellent outcome following transplantation of a domino donor liver with high-grade macrosteatosis

Severe macrosteatosis in the donor liver is considered a major predictive factor of primary graft non-function. Such livers are usually discarded despite an ever-growing need for donor livers. We report our recent experience in a patient (#1) who had an excellent outcome following liver transplantation (LT) of a 65-70% macrosteatotic graft and compare his findings with those of two other (#2 and #3) recipients of moderate to severe macrosteatotic grafts. Both patients (#2 and #3) had initial diminished function, with recovery in patient #2 but delayed graft non-function requiring re-LT (day 24) in patient #3. Patient #1 had no intra-operative complications, while patient #2 had mild complications due to prior adhesions and graft capsular laceration. In patient #3, extensive intra-abdominal adhesions resulting in excessive bleeding occurred during recipient hepatectomy. Total ischemic times: 2.48, 6.10, and 8.18 h; total blood product usage: 43, 81, and 223 units; post-LT hospital stay: 9, 21, and 69 days were seen in patients #1, #2 and #3, respectively. In conclusion, post-LT excellent graft function was seen in one recipient of 65-70% macrosteatotic graft. Transplantation of grafts with moderate/severe macrosteatosis may be inadvisable in patients with extensive intra-abdominal adhesions with expectant excessive bleeding and long ischemia times.

Porcine partial liver transplantation: a novel model of the "small-for-size" liver graft

Increasing shortage of cadaveric grafts demands the utilization of living donor and split liver grafts. The purpose of this study was to 1) define the "small-for-size" graft in a pig liver transplant model 2) evaluate pathological changes associated with small-for-size liver transplantation. Pigs were divided into four groups based on the volume of transplanted liver: (a) control group (n=4), 100% liver volume (LV) (b) group I (n=8), 60% LV (c) group II (n=8), 30% LV (d) group III (n=15), 20% LV. Tacrolimus and methyl prednisone were administered as immunosuppression. Animals were followed for 5 days with daily serum biochemistry, liver biopsies on day 3 and 5 for light microscopy, and tissue levels of thymidine kinase (TK) and ornithine decarboxylase (ODC). Liver grafts were weighed pretransplant and at sacrifice. All the recipients of 100%, 60%, and 30% grafts survived. Transplantation of 20% grafts (group III) resulted in a 47% mortality rate. Group III animals showed significantly prolonged prothrombin times (p<0.05), elevated bilirubin levels (p<0.05), and ascites. The rate of regeneration, as indicated by TK activity and graft weight was inversely proportional to the size of the transplanted graft. The severity of the microvascular injury was inversely proportional to graft size and appeared to be the survival-limiting injury. Frank rupture of the sinusoidal lining, parenchymal hemorrhage, and portal vein injury were prominent in group III animals 1 hour following reperfusion. This study established a reproducible large animal model of partial liver grafting; it defined the small-for-size syndrome in this model and described the associated microvascular injury.

Hepatobiliary pathology

Technologic advances using cDNA microarray hybridization, liver diseases characterized by mitochondrial DNA depletion, and new work characterizing bile salt transport problems in familial intrahepatic cholestasis syndromes were some of the major highlights of this past year. Analysis of normal livers by cDNA microarrays disclosed 2418 unique gene transcripts encoding a host of cellular structural and functional proteins. This technique was also applied to hepatocellular carcinoma, where enhanced expression of a number of genes involved in antiapoptosis and cell transformation may shed additional light on the process of hepatocarcinogenesis. Mitochondrial DNA depletion seen in Navajo neurohepatopathy and in respiratory chain disorders of infancy was associated with cholestasis and cirrhosis in the former and microvesicular steatosis and oncocytic transformation (mitochondrial hyperplasia) in the latter. Pathologists who routinely examine liver biopsies after liver or bone marrow transplantation should be aware of unusual biopsy features that mimic other diseases, such as the autoimmune hepatitis-like syndrome that may follow liver transplantation and chronic graft-versus-host disease that clinically and pathologically resembles acute hepatitis.

Critical care of the liver transplant patient: an update

The unique pathophysiology of patients with end-stage liver disease has important implications for their critical care treatment, particularly in the postoperative state. To gauge hemodynamic parameters and responses, each patient must be carefully evaluated for their place in the clinical spectrum of cirrhosis and portal hypertension. Although the data are limited, the biology of the consequences of liver disease is emphasized by novel treatments of hepatorenal syndrome, portopulmonary hypertension, and hepatopulmonary syndrome. These issues become more relevant with increased adult-to-adult living donor liver transplantation, in which technical considerations may further complicate the general treatment of the postoperative transplant patient.