- Email: [email protected]
Grade of donor liver microvesicular steatosis does not affect the postoperative outcome after liver transplantation
Liver transplantation and microvesicular steatosis Original Article / Transplantation
Grade of donor liver microvesicular steatosis does not affect the postoperative outcome after liver transplantation Anne Andert, Tom Florian Ulmer, Wenzel Schöning, Daniela Kroy, Marc Hein, Patrick Hamid Alizai, Christoph Heidenhain, Ulf Neumann and Maximilian Schmeding Aachen, Germany
BACKGROUND: The potential effect of graft steatosis on the postoperative liver function is discussed controversially. The present study aimed to evaluate the effect of the donor liver microvesicular steatosis on the postoperative outcome after liver transplantation.
CONCLUSION: Microvesicular steatosis of donor livers has no negative effect on the postoperative outcome after liver transplantation. (Hepatobiliary Pancreat Dis Int 2017;16:617-623)
METHODS: Ninety-four patients undergoing liver transplan- KEY WORDS: liver transplantation; liver steatosis; tation at the University Hospital Aachen were included in microvesicular steatosis; this study. The patient cohort was divided into three groups early allograft dysfunction according to the grade of microvesicular steatosis (MiS): MiS <30% (n=27), MiS 30%-60% (n=41) and MiS >60% (n=26). The outcomes after liver transplantation were evaluated, including the 30-day and 1-year patient and graft survival rates Introduction and the incidences of early allograft dysfunction (EAD) and rgan shortage is a major problem in liver transprimary nonfunction (PNF). RESULTS: The incidences of EAD and PNF did not differ significantly between the groups. We observed 5 cases of PNF, one occurred in the MiS <30% group and 4 in the MiS 30%60% group. The 30-day and 1-year graft survivals did not differ significantly between groups. The 30-day patient survival rates were 100% in all groups. The 1-year patient survival rates were 94.4% in the MiS <30% group, 87.9% in the MiS 30%-60% group and 90.9% in the MiS >60% group.
Author Affiliations: Department of General, Visceral and Transplant Surgery (Andert A, Ulmer TF, Schöning W, Alizai PH, Neumann U and Schmeding M), Department of Internal Medicine (Kroy D) and Department of Anaesthesiology (Hein M), Uniklinik RWTH Aachen, Aachen, Germany; Department of General and Visceral Surgery, Sana Hospital Düsseldorf-Gerresheim, Germany (Heidenhain C) Corresponding Author: Anne Andert, MD, Department of General, Visceral and Transplant Surgery, Uniklinik RWTH Aachen, Pauwelsstr. 30, Aachen 52074, Germany (Tel: +49-241-80-35466; Fax: +49-241-80-82417; Email: [email protected]) © 2017, Hepatobiliary Pancreat Dis Int. All rights reserved. doi: 10.1016/S1499-3872(17)60064-X Published online October 24, 2017.
O
plantation. The use of extended criteria donors has become the most important strategy to increase the donor pool and reduce the number of patients who die on the liver transplantation waiting list. Not all extended donor criteria have the same influence on the postoperative outcome after liver transplantation. Donor age, degree of liver steatosis and cold ischemic time (CIT) seem to be more relevant in regards to postoperative outcomes.[1-3] The potential effect of graft steatosis on the postoperative liver function is discussed controversially. Some studies revealed a negative impact with high incidence of early allograft dysfunction (EAD) and primary nonfunction (PNF),[4-7] others suggested that grafts with moderate or even severe steatosis can be safely transplanted without increased graft dysfunction.[8, 9] Furthermore, the relevance of the type of steatosis, micro- or macrovesicular, is still unclear. Macrovesicular steatosis seems to be a benign, potentially reversible condition. It is mostly associated with obesity and alcohol consumption.[10] Microvesicular steatosis is considered a more serious condition often associated with impaired mitochondrial beta-oxidation and, therefore, a less favorable prognosis.[11] The importance of graft steatosis will further increase
Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 617
Hepatobiliary & Pancreatic Diseases International
in the future. In deceased organ donors, liver steatosis has been documented in up to 30% of allografts during the 1990s.[4, 12, 13] With the rising incidence of obesity and metabolic syndrome in the population, the number of donors with liver steatosis will increase. However, whether to implant or to reject a steatotic liver still depends mainly on the experience of the transplant surgeon, due to insufficient data on the effect of graft steatosis. The aim of our study was to evaluate the effect of the microvesicular steatosis of the donor liver on the postoperative outcomes after liver transplantation, with special regard to the incidence of EAD and PNF.
Methods Between May 2010 and July 2016, 290 patients underwent liver transplantations at the University Hospital Aachen. Only patients with pre-reperfusion liver biopsies at the time of transplantation were included in this analysis. Patients with missing data on donor histology were excluded. Furthermore, sixteen patients with combined kidney-liver transplantation, living-donor liver transplantation and split liver transplantation were excluded. Finally, we included 94 patients in this retrospective analysis. Liver biopsies were obtained during organ procurement and examined by the pathologist at the Institute of Pathology at the University Hospital Essen. Steatosis of the liver biopsies was determined on HE- and OROstained sections. Microvesicular steatosis was defined as at least one, usually numerous small lipid droplets smaller in size than the nucleus and not displacing the nucleus.[14] Surgical techniques as well as intraoperative and postoperative care were standardized. All liver transplantations were performed with an extracorporeal veno-venous/porto-systemic bypass as previously described.[15] The initial immunosuppression consisted of induction therapy with basiliximab (20 mg intraoperatively and on postoperative day [POD] 4), tacrolimus (trough level 10 µg/L), and corticosteroids (250 mg intraoperatively, 1 mg/kg on POD 1, and subsequent tapering). The following data of the recipients were collected: gender, age, etiology of disease and lab-MELD score. The following donor data were examined: gender, age, body mass index (BMI), CIT, bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), creatinine level, grade of microand macrovesicular liver steatosis and length of intensive care unit (ICU) stay. The extended donor criteria were defined according to the German Medical Association: bilirubin >3 mg/dL, AST or ALT >150 U/L, age >65 years, ICU stay >7 days, BMI >30 kg/m2, or serum sodium concentration >165
mmol/L.[16] Furthermore, operative time, transfusion requirement, warm ischemic time (WIT) and type of organ allocation were analyzed. The outcome of liver transplantation was evaluated by the following parameters: length of ICU stay, duration of hospitalization, 30-day and 1-year patient survival, 30day and 1-year graft survival, and incidence of EAD and PNF. EAD was defined as follows: bilirubin ≥10 mg/dL on POD 7 and/or INR ≥1.6 on POD 7 and/or AST or ALT >2000 U/L within the first 7 days.[6] According to specifications of Eurotransplant, PNF was defined as re-transplantation or death within 7 days after liver transplantation. The incidence of rejections, postoperative acute renal failure requiring continuous renal replacement therapy and postoperative liver enzyme and creatinine values were also analyzed. Laboratory values were measured preoperatively (pre), immediately postoperatively (post), 24 hours postoperatively (POD 1) and on PODs 3, 7 and 14. Acute renal failure was defined as an increase in serum creatinine of more than 50% combined with oliguria, anuria or the need for renal replacement therapy on PODs 1-14. The patient follow-up period ended in August 2016. At that time, the mean follow-up was 856 days and 73 patients had been followed for at least one year.
Statistical analysis Statistical analyses were performed with SPSS statistical software (IBM®, SPSS® Statistics 20, Chicago, IL, USA) using the Chi-square test or the Fisher,s exact test for qualitative variables and the Kruskal-Wallis-Test or the univariate ANOVA for continuous variables. For continuous variables, the results are presented as median and range. The Kaplan-Meier method and the log-rank test were used to estimate and compare observed graft and patient survival. A two-sided P value of <0.05 was considered significant.
Results The patient cohort was first divided into three groups according to the grade of microvesicular steatosis (MiS) of the donor liver regardless of the degree of macrovesicular steatosis. Twenty-seven patients belonged to the MiS <30% group. The MiS 30%-60% group included 41 patients. Twenty-six patients belonged to the MiS >60% group.
Recipient characteristics The recipient characteristics did not differ significantly between the three groups. The median age was 58 years in the MiS <30% group, 54 in the MiS 30%-60% group and 57 in the MiS >60% group. The majority of the patients were male (81% in the MiS <30% group, 68% in the MiS 30%-60% group and 65% in the MiS >60%
618 • Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com
Liver transplantation and microvesicular steatosis
group). The median lab-MELD score was 15 in the MiS <30% group and 16 in the other two groups. The primary causes for liver transplantation were hepatocellular carcinoma (37%, 22% and 31%, respectively) and alcohol-induced cirrhosis (26%, 34% and 23%, respectively). The recipient demographics are shown in Table 1.
Donor characteristics The median BMI was 28 kg/m2 in all groups. The median donor age was 66 years in the MiS <30% group, 50 years in the MiS 30%-60% group and 59 years in the MiS >60% group. The median CIT was 460 minutes in the MiS <30% group, 482 minutes in the MiS 30%60% group and 465 minutes in the MiS >60% group. Fifty-nine percent of the organs were allocated by an extended allocation procedure in the MiS <30% group, 68% in the MiS 30%-60% group and 58% in the MiS >60% group. The grade of macrovesicular steatosis differed significantly between the three groups. The MiS <30% and MiS >60% groups had a median degree of 15%. In the MiS 30%-60% group, donor livers had a median degree of 30% (P=0.043). Table 2 shows donor characteristics. Intraoperative data The median WITs in the different groups were 40, 40 and 41 minutes, respectively. The patients in all three groups had a median intraoperative requirement of 6 units packed cell. Fifteen units fresh frozen plasma were used in the MiS <30% group, 10 in the MiS 30%-60% group and 12 in the MiS >60% group. The intraoperative data are shown in Table 3.
Table 2. Donor characteristics MiS <30% (n=27) 28 (23-50) 66 (34-74) 460 (355-600)
MiS 30%60% (n=41) 28 (19-40) 50 (22-80) 482 (265-780)
MiS >60% (n=26) 28 (21-47) 59 (22-83) 465 (311-588)
P value 0.172 0.747 0.400
Age >65 yr ICU stay >7 d AST or ALT >150 U/L Bilirubin >3 mg/dL Na >165 mmol/L BMI >30 kg/m2 Macrovesicular steatosis (%)
13 (48%) 14 (52%) 9 (33%) 2 (7%) 2 (7%) 12 (44%) 15 (0-90)
14 (34%) 7 (17%) 10 (24%) 0 3 (7%) 14 (34%) 30 (0-80)
8 (31%) 3 (12%) 9 (35%) 1 (4%) 4 (15%) 10 (38%) 15 (0-40)
0.400 0.002 0.652 0.154 0.486 0.712 0.043
Extended allocation
16 (59%) 28 (68%)
Characteristics BMI (kg/m2) Age (yr) Cold ischemic time (min) Extended donor criteria
15 (58%) 0.405
Table 3. Intraoperative data Variables Packed cell (U) Fresh frozen plasma (U) Platelet concentrate (U)
MiS <30% (n=27) 6 (0-28) 15 (10-48)
MiS 30%-60% (n=41) 6 (2-16) 10 (7-20)
0 (0-4)
0 (0-4)
Warm ischemic time 40 (33-67) 40 (20-56) (min)
MiS >60% P value (n=26) 6 (2-36) 0.252 12 (6-50) 0.096 1 (0-3)
0.996
41 (35-60) 0.496
Table 4. Postoperative data Table 1. Recipient characteristics Characteristics Age (yr) Gender (M/F) Indication for LT Acute liver failure Alcohol-induced cirrhosis HCC PSC/PBC Graft failure HCV/HBV NASH cirrhosis Other Lab-MELD Lab-MELD ≥30
MiS <30% (n=27) 58 (19-69) 22/5
MiS 30%-60% MiS >60% (n=41) (n=26) 54 (44-68) 57 (26-63) 28/13 17/9
1 (4%) 4 (10%) 7 (26%) 14 (34%)
1 (4%) 6 (23%)
10 (37%) 9 (22%) 4 (15%) 2 (5%) 1 (4%) 2 (5%) 2 (7%) 5 (12%) 1 (4%) 2 (5%) 1 (4%) 3 (7%) 15 (7-40) 16 (6-34) 4 (15%) 2 (5%)
8 (31%) 4 (15%) 0 2 (8%) 0 5 (19%) 16 (6-34) 3 (12%)
Variables P value 0.669 0.386 0.638
0.980 0.635
HCC: hepatocellular carcinoma; PSC: primary sclerosing cholangitis; PBC: primary biliary cirrhosis; HCV: hepatitis C virus; HBV: hepatitis B virus; NASH: nonalcoholic steatohepatitis; MELD: model for endstage liver disease.
Early allograft dysfunction Primary nonfunction Rejection Mild Moderate Severe CVVH Renal failure ICU stay (d) Hospital stay (d) 30-day mortality 1-year mortality 30-day re-transplantation 1-year re-transplantation
MiS <30% (n=27) 13 (48%) 1 (4%)
MiS 30%-60% MiS >60% P value (n=41) (n=26) 20 (49%) 7 (27%) 0.157 4 (10%)
6 (22%) 5 (12%) 0 0 1 (4%) 1(2%) 4 (15%) 9 (22%) 9 (33%) 12 (29%) 4 (2-113) 4 (2-178) 28 (13-113) 25 (13-178) 0 0 1/18 (6%) 4/33 (12%) 2 (7%) 5 (12%) 2/18 (11%)
5/33 (15%)
0 7 (27%) 1 (4%) 0 1 (4%) 4 (15%) 5 (2-22) 24 (15-72) 0 2/22 (9%) 0
0.269 0.339
0.120 0.305 0.349 0.598 1.000 0.882 0.197
1/22 (5%) 0.566
CVVH: continuous venovenous hemofiltration.
Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 619
Hepatobiliary & Pancreatic Diseases International
Postoperative data The median length of hospital stay after liver transplantation was 28 days in the MiS <30% group, 25 days in the MiS 30%-60% group and 24 days in the MiS >60% group. The patients in the MiS <30% and MiS 30%-60% groups had a median ICU stay of 4 days after liver transplantation. Patients in the MiS >60% group had a median ICU stay of 5 days. The incidence of EAD and PNF did not differ significantly in the different groups (P=0.157 and P=0.269) (Table 4). The MiS <30% group had an incidence of EAD of 48%. Forty-nine percent of patients in the MiS 30%-60% group developed EAD compared to 27% in the MiS >60% group. The most frequent criterion leading to the diagnosis of EAD was elevated liver enzymes within the first POD 7. We observed 5 cases of PNF. One occurred in the MiS <30% group and 4 in the MiS 30%-60% group. Significant differences of the postoperative laboratory values could only be observed for AST and ALT immediately after surgery and on POD 1. The median AST concentrations immediately after surgery were significantly higher in the MiS 30%-60% group [1313 vs 1191 U/L (MiS <30%) and 931 U/L (MiS >60%), P=0.013]. On POD 1, the
MiS <30% group had the highest concentration of AST [1129 vs 768 U/L (MiS 30%-60%) and 524 U/L (MiS >60%), P=0.015)(Fig. 1A). The ALT concentration immediately after surgery was significantly higher in the MiS >60% group (628 U/L) than in the MiS <30% (522 U/L) and the MiS 30%-60% groups (536 U/L) (P=0.041)(Fig. 1B). On POD 3-14, there were no differences in the median aminotransferase values between three groups. The grade of MiS was not related to bilirubin, GLDH or creatinine levels during the observation period. The incidence of acute renal failure and need for renal replacement therapy was not significantly different between three groups. All patients who required renal replacement therapy recovered without the need for permanent dialysis. Creatinine values at 6 months after liver transplantation were not significantly different between the three groups (P=0.292). The number of rejections was not different between the groups (P=0.339). The 30-day graft survival was 92.6% in the MiS <30% group, 87.8% in the MiS 30%-60% group and 100% in the MiS >60% group (P=0.187) (Fig. 2A). The 1-year graft survival was 89.5% in the MiS <30% group, 85.3%
Fig. 1. Postoperative ALT and AST values. A, B: aminotransferase values of all grafts. C, D: aminotransferase values after exclusion of the grafts with macrovesicular steatosis.
620 • Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com
Liver transplantation and microvesicular steatosis
in the MiS 30%-60% group and 95.5% in the MiS >60% group (P=0.481) (Fig. 2B). In the MiS <30% group, two re-transplantations were performed, one because of ischemic type biliary lesion (ITBL) and one because of PNF. All 5 re-transplantations in the MiS 30%-60% were necessary because of PNF. In the MiS >60% group, one re-transplantations was performed because of HCV recurrence. The 30-day patient survival rates were 100% in all groups. The 1-year patient survival rates were 94.4% in the MiS <30% group, 87.9% in the MiS 30%-60% group and 90.9% in the MiS >60% group (P=0.748) (Fig. 2C). In a second step we excluded all donor livers with a degree of macrovesicular steatosis of more than 10% to make sure that the degree of macrovesicular steatosis did not influence our results. Fifteen patients still belonged to the MiS <30% group and to the MiS 30%-60% group. The MiS >60% group included 14 patients. After Table 5. Postoperative data (liver grafts with macrovesicular steatosis >10% excluded) Variables Early allograft dysfunction Primary nonfunction Rejection Mild Moderate Severe CVVH Renal failure ICU stay (d) Hospital stay (d) 30-day mortality 1-year mortality 30-day re-transplantation 1-year re-transplantation
MiS <30% MiS 30%-60% MiS >60% P value (n=15) (n=15) (n=14) 3 (20%) 3 (20%) 1 (7%) 0.668 0
0
2 (13%) 4 (27%) 0 0 1 (7%) 0 2 (13%) 2 (13%) 4 (27%) 4 (27%) 4 (2-21) 4 (3-18) 25 (15-57) 25 (13-55) 0 0 0 1/12 (8%) 1 (7%) 1 (7%) 1/10 (10%) 1/12 (8%)
CVVH: continuous venovenous hemofiltration.
0 2 (14%) 1 (7%) 0 1 (7.1%) 2 (14%) 4 (2-10) 28 (15-55) 0 0 0 0
1.000 0.715
1.000 0.734 0.457 0.740 1.000 1.000 1.000 0.750
exclusion of the grafts with macrovesicular steatosis we could not observe differences in matters of the previous analysis. Table 5 provides the results of the postoperative data. The incidence of EAD and PNF as well as the number of re-transplantation and mortality did not differ significantly between the three groups. The only difference we observed after exclusion of the grafts with macrovesicular steatosis was the course of the postoperative aminotransferase values. In contrast to the first analysis, we could not observe significant differences between the three groups (Fig. 1C, D) immediate after surgery (AST, P=0.108; ALT, P=0.623) and on POD 1 (AST, P=0.386; ALT, P=0.538).
Discussion The aim of our study was to examine the influence of donor liver microvesicular steatosis on postoperative outcomes after liver transplantation. Several studies[4, 5, 8, 9] have investigated the effect of donor liver steatosis on patient outcome after liver transplantation. However, only inconsistent data existed and whether micro- or macrovesicular steatosis is of more importance remained unclear. On the one hand, the lack of consistency among various studies was caused by different parameters and endpoints analyzed. On the other hand, there was an enormous variability in definitions of types and amounts of steatosis. Furthermore, the formation of groups (micro- or macrovesicular steatosis) for statistical analysis is difficult, because most of the liver grafts offer both types of steatosis. Sharkey et al described an overlap between the different groups.[17] Therefore, we performed an analysis in two steps. First, the patient cohort was divided into groups according to the grade of microvesicular steatosis regardless of the degree of macrovesicular steatosis. In a second step, we excluded grafts with a degree of macrovesicular steatosis of more than 10% to make sure that the degree of macrovesicular steatosis did not influence our results. Most studies[18-20] evaluated the effect of macrovesicular
Fig. 2. The graft and patients survival. Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 621
Hepatobiliary & Pancreatic Diseases International
steatosis, even though microvesicular steatosis is considered to be a more serious condition, often associated with impaired mitochondrial beta-oxidation and, therefore, a less favorable prognosis.[11] The main concern with using donor organs with steatosis is a higher incidence of EAD and PNF with consequently, early re-transplantation.[6, 7, 21] We did not observe significant differences between the three groups with regard to the incidence of EAD. The MiS <30% and MiS 30%-60% groups had significantly higher peaks of AST immediately postoperative and on POD 1 (Fig. 1A, B), leading to a discreet higher number of EAD in the MiS <30% and the MiS 30%-60% groups. ALT concentration immediately postoperative was significant higher in the MiS >60% group, but without an effect on the rate of EAD. After exclusion of the liver grafts with macrovesicular steatosis, there were no differences of the postoperative aminotransferase values between the three groups (Fig. 1C, D) and no effect on the rate of EAD. Afonso et al[8] made the same observations in a retrospective analysis of 48 liver transplant patients. Grafts without microvesicular steatosis, with microvesicular steatosis <50% and >50% were compared, and no influence on initial liver function after liver transplantation was found (P=0.547). Sharkey et al[17] identified two subgroups of microsteatosis, termed high-grade and low-grade microsteatosis. Low-grade microsteatosis was defined as several small vesicles that neither filled the cell cytoplasm nor caused cell enlargement. High-grade microsteatosis presented many small vesicles that filled the cell cytoplasm with cell enlargement. They revealed that the presence of highgrade microsteatosis was more likely to be associated with delayed graft function in the postoperative period and that the amount of steatosis is of less importance. It should be noted that postoperative liver function was only evaluated by serum lactate level. Therefore, their study suggested that the excess in poor patient outcomes observed in association with macrosteatosis in other studies was actually related to the subgroup with high-grade microsteatosis, rather than to the amount of microsteatosis per se. Cieślak et al[22] did a retrospective analysis of 269 liver transplantations. They found that the risk of EAD was significantly related to hepatic microvesicular steatosis (P<0.021). A 50% increased risk of EAD was equivalent to a 12% increase in the extent of steatosis. Yoong et al[23] confirmed the negative effect of microsteatosis on postoperative liver function. They analyzed the outcome of 116 patients after re-liver transplantation and suggested that severe donor liver steatosis, of the microvesicular type, involving more than 66% of hepatocytes was associated with a significantly higher rate of EAD (P<0.01). In our cohort, the number of PNF cases did not differ significantly between the groups. Fishbein et al[9] made
the same observation. The grade of microvesicular steatosis did not affect the number of PNF cases. Interestingly, patient and graft survival in the MiS <30% group was not different from that in the MiS 30%-60% or >60% groups. Fishbein et al made the same observation in their patient cohort. The 1-year patient and graft survival rates were 80% and 72.5%, without any differences to the overall population.[9] Afonso et al[8] confirmed these results, in that, within their patients, collective microvesicular steatosis had no impact on 30-day mortality (P=0.380). In contrast to our results, Yoong et al found a worse outcome after re-liver transplantation. All grafts with severe microvesicular steatosis failed, following a median survival of 1.5 months.[23] Another important topic is the assessment of donor liver fat because it is a difficult task for the transplant team.[24] The histological analysis by a pathologist is the gold standard to assess liver steatosis.[25, 26] Liver steatosis >30% belongs to the extended donor criteria assessed by the German Medical Association.[16] However, McCormack et al showed that liver biopsy at the time of procurement for liver transplantation is rarely performed.[27] Only 23% of liver transplant recipients in the United Network for Organ Sharing had a liver donor biopsy recorded. We made the same observation in our transplant center. We could only include 32% of our collective liver transplantation patients because of missing donor histology. Furthermore, the staining technique plays an important role because it could affect the grading of steatosis.[28] Lo et al[29] showed that HE-stained frozen biopsy overestimates microsteatosis but underestimates macrosteatosis, when compared with permanent sections using a more specific staining modality. El-Badry et al[26] revealed that quantification of liver steatosis in histological sections is strongly observer-dependent, not reproducible, and does not correlate with the computerized estimation. Therefore, they advocate that the current standards of assessment and the clinical relevance of liver steatosis for liver surgery and transplantation should be challenged. Some limitations exist concerning the evaluation of our data. First, this analysis was performed retrospectively. Furthermore, the number of patients was relatively small. Multivariate analyses in larger patient collectives need to be performed to categorize the impact of donor microvesicular steatosis, within the context of other marginal donor criteria. In conclusion, microvesicular steatosis in donor livers has no negative effect on the postoperative outcomes after liver transplantation. Based on our findings, livers with either mild or severe microsteatosis can safely be transplanted. Contributors: AA, NU and SM proposed the study. AA, UTF, SW, KD, HM and APH collected and analyzed the data. AA and
622 • Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com
Liver transplantation and microvesicular steatosis
mann N, et al. Liver steatosis in pre-transplant liver biopsies SM wrote the manuscript. All authors revised the manuscript critically. AA is the guarantor. can be quantified rapidly and accurately by nuclear magnetic Funding: None. resonance analysis. Virchows Arch 2017;470:197-204. Ethical approval: This study was approved by the Ethics Com- 15 Mossdorf A, Ulmer F, Junge K, Heidenhain C, Hein M, Temmittee of the RWTH Aachen University Hospital. izel I, et al. Bypass during liver transplantation: anachronism Competing interest: No benefits in any form have been received or revival? Liver transplantation using a combined venoveor will be received from a commercial party related directly or nous/portal venous bypass-experiences with 163 liver transindirectly to the subject of this article. plants in a newly established liver transplantation program. Gastroenterol Res Pract 2015;2015:967951. 16 Schrem H, Reichert B, Frühauf N, Kleine M, Zachau L, Becker T, et al. Extended donor criteria defined by the German References Medical Association: study on their usefulness as prognostic 1 Nickkholgh A, Weitz J, Encke J, Sauer P, Mehrabi A, Büchler model for early outcome after liver transplantation. Chirurg MW, et al. Utilization of extended donor criteria in liver trans2012;83:980-988. plantation: a comprehensive review of the literature. Nephrol 17 Sharkey FE, Lytvak I, Prihoda TJ, Speeg KV, Washburn WK, Dial Transplant 2007;22:viii29-viii36. Halff GA. High-grade microsteatosis and delay in hepatic 2 Busuttil RW, Farmer DG, Yersiz H, Hiatt JR, McDiarmid SV, function after orthotopic liver transplantation. Hum Pathol Goldstein LI, et al. Analysis of long-term outcomes of 3200 2011;42:1337-1342. liver transplantations over two decades: a single-center experi- 18 Gwiasda J, Schrem H, Klempnauer J, Kaltenborn A. Identifyence. Ann Surg 2005;241:905-918. ing independent risk factors for graft loss after primary liver 3 Tector AJ, Mangus RS, Chestovich P, Vianna R, Fridell JA, transplantation. Langenbecks Arch Surg 2017;402:757-766. Milgrom ML, et al. Use of extended criteria livers decreases 19 Kulik U, Lehner F, Klempnauer J, Borlak J. Primary non-funcwait time for liver transplantation without adversely impacting tion is frequently associated with fatty liver allografts and high posttransplant survival. Ann Surg 2006;244:439-450. mortality after re-transplantation. Liver Int 2017;37:1219-1228. 4 Marsman WA, Wiesner RH, Rodriguez L, Batts KP, Porayko 20 Choi WT, Jen KY, Wang D, Tavakol M, Roberts JP, Gill RM. MK, Hay JE, et al. Use of fatty donor liver is associated with Donor liver small droplet macrovesicular steatosis is associdiminished early patient and graft survival. Transplantation ated with increased risk for recipient allograft rejection. Am J 1996;62:1246-1251. Surg Pathol 2017;41:365-373. 5 Adam R, Reynes M, Johann M, Morino M, Astarcioglu I, Kaf21 López-Navidad A, Caballero F. Extended criteria for organ acetzis I, et al. The outcome of steatotic grafts in liver transplanceptance. Strategies for achieving organ safety and for increastation. Transplant Proc 1991;23:1538-1540. ing organ pool. Clin Transplant 2003;17:308-324. 6 Olthoff KM, Kulik L, Samstein B, Kaminski M, Abecassis M, 22 Cieślak B, Lewandowski Z, Urban M, Ziarkiewicz-Wróblewska Emond J, et al. Validation of a current definition of early alB, Krawczyk M. Microvesicular liver graft steatosis as a risk lograft dysfunction in liver transplant recipients and analysis factor of initial poor function in relation to suboptimal donor of risk factors. Liver Transpl 2010;16:943-949. parameters. Transplant Proc 2009;41:2985-2988. 7 Bzeizi KI, Jalan R, Plevris JN, Hayes PC. Primary graft dys23 Yoong KF, Gunson BK, Neil DA, Mirza DF, Mayer AD, Buckfunction after liver transplantation: from pathogenesis to preels JA, et al. Impact of donor liver microvesicular steatosis vention. Liver Transpl Surg 1997;3:137-148. on the outcome of liver retransplantation. Transplant Proc 8 Afonso RC, Saad WA, Parra OM, Leitão R, Ferraz-Neto BH. 1999;31:550-551. Impact of steatotic grafts on initial function and prognosis af24 McCormack L, Dutkowski P, El-Badry AM, Clavien PA. Liver ter liver transplantation. Transplant Proc 2004;36:909-911. transplantation using fatty livers: always feasible? J Hepatol 9 Fishbein TM, Fiel MI, Emre S, Cubukcu O, Guy SR, Schwartz 2011;54:1055-1062. ME, et al. Use of livers with microvesicular fat safely expands 25 Silva MA. Putting objectivity into assessment of steatosis. the donor pool. Transplantation 1997;64:248-251. Transplantation 2009;88:620-621. 10 Hu KQ, Kyulo NL, Esrailian E, Thompson K, Chase R, Hillebrand DJ, et al. Overweight and obesity, hepatic steatosis, 26 El-Badry AM, Breitenstein S, Jochum W, Washington K, Paradis V, Rubbia-Brandt L, et al. Assessment of hepatic steatosis and progression of chronic hepatitis C: a retrospective study by expert pathologists: the end of a gold standard. Ann Surg on a large cohort of patients in the United States. J Hepatol 2009;250:691-697. 2004;40:147-154. 11 Fromenty B, Berson A, Pessayre D. Microvesicular steatosis 27 McCormack L, Petrowsky H, Jochum W, Mullhaupt B, Weber M, Clavien PA. Use of severely steatotic grafts in liver and steatohepatitis: role of mitochondrial dysfunction and liptransplantation: a matched case-control study. Ann Surg id peroxidation. J Hepatol 1997;26:13-22. 2007;246:940-948. 12 Angele MK, Rentsch M, Hartl WH, Wittmann B, Graeb C, Jauch KW, et al. Effect of graft steatosis on liver function 28 Selzner M, Clavien PA, et al. Fatty liver in liver transplantation and surgery. Semin Liver Dis 2001;21:105-113. and organ survival after liver transplantation. Am J Surg 29 Lo IJ, Lefkowitch JH, Feirt N, Alkofer B, Kin C, Samstein B, 2008;195:214-220. et al. Utility of liver allograft biopsy obtained at procurement. 13 Verran D, Kusyk T, Painter D, Fisher J, Koorey D, Strasser S, Liver Transpl 2008;14:639-646. et al. Clinical experience gained from the use of 120 steatotic donor livers for orthotopic liver transplantation. Liver Transpl Received February 10, 2017 2003;9:500-505. 14 Bertram S, Myland C, Swoboda S, Gallinat A, Minor T, LehAccepted after revision June 23, 2017 Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 623
Grade of donor liver microvesicular steatosis does not affect the postoperative outcome after liver transplantation Anne Andert, Tom Florian Ulmer, Wenzel Schöning, Daniela Kroy, Marc Hein, Patrick Hamid Alizai, Christoph Heidenhain, Ulf Neumann and Maximilian Schmeding Aachen, Germany
BACKGROUND: The potential effect of graft steatosis on the postoperative liver function is discussed controversially. The present study aimed to evaluate the effect of the donor liver microvesicular steatosis on the postoperative outcome after liver transplantation.
CONCLUSION: Microvesicular steatosis of donor livers has no negative effect on the postoperative outcome after liver transplantation. (Hepatobiliary Pancreat Dis Int 2017;16:617-623)
METHODS: Ninety-four patients undergoing liver transplan- KEY WORDS: liver transplantation; liver steatosis; tation at the University Hospital Aachen were included in microvesicular steatosis; this study. The patient cohort was divided into three groups early allograft dysfunction according to the grade of microvesicular steatosis (MiS): MiS <30% (n=27), MiS 30%-60% (n=41) and MiS >60% (n=26). The outcomes after liver transplantation were evaluated, including the 30-day and 1-year patient and graft survival rates Introduction and the incidences of early allograft dysfunction (EAD) and rgan shortage is a major problem in liver transprimary nonfunction (PNF). RESULTS: The incidences of EAD and PNF did not differ significantly between the groups. We observed 5 cases of PNF, one occurred in the MiS <30% group and 4 in the MiS 30%60% group. The 30-day and 1-year graft survivals did not differ significantly between groups. The 30-day patient survival rates were 100% in all groups. The 1-year patient survival rates were 94.4% in the MiS <30% group, 87.9% in the MiS 30%-60% group and 90.9% in the MiS >60% group.
Author Affiliations: Department of General, Visceral and Transplant Surgery (Andert A, Ulmer TF, Schöning W, Alizai PH, Neumann U and Schmeding M), Department of Internal Medicine (Kroy D) and Department of Anaesthesiology (Hein M), Uniklinik RWTH Aachen, Aachen, Germany; Department of General and Visceral Surgery, Sana Hospital Düsseldorf-Gerresheim, Germany (Heidenhain C) Corresponding Author: Anne Andert, MD, Department of General, Visceral and Transplant Surgery, Uniklinik RWTH Aachen, Pauwelsstr. 30, Aachen 52074, Germany (Tel: +49-241-80-35466; Fax: +49-241-80-82417; Email: [email protected]) © 2017, Hepatobiliary Pancreat Dis Int. All rights reserved. doi: 10.1016/S1499-3872(17)60064-X Published online October 24, 2017.
O
plantation. The use of extended criteria donors has become the most important strategy to increase the donor pool and reduce the number of patients who die on the liver transplantation waiting list. Not all extended donor criteria have the same influence on the postoperative outcome after liver transplantation. Donor age, degree of liver steatosis and cold ischemic time (CIT) seem to be more relevant in regards to postoperative outcomes.[1-3] The potential effect of graft steatosis on the postoperative liver function is discussed controversially. Some studies revealed a negative impact with high incidence of early allograft dysfunction (EAD) and primary nonfunction (PNF),[4-7] others suggested that grafts with moderate or even severe steatosis can be safely transplanted without increased graft dysfunction.[8, 9] Furthermore, the relevance of the type of steatosis, micro- or macrovesicular, is still unclear. Macrovesicular steatosis seems to be a benign, potentially reversible condition. It is mostly associated with obesity and alcohol consumption.[10] Microvesicular steatosis is considered a more serious condition often associated with impaired mitochondrial beta-oxidation and, therefore, a less favorable prognosis.[11] The importance of graft steatosis will further increase
Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 617
Hepatobiliary & Pancreatic Diseases International
in the future. In deceased organ donors, liver steatosis has been documented in up to 30% of allografts during the 1990s.[4, 12, 13] With the rising incidence of obesity and metabolic syndrome in the population, the number of donors with liver steatosis will increase. However, whether to implant or to reject a steatotic liver still depends mainly on the experience of the transplant surgeon, due to insufficient data on the effect of graft steatosis. The aim of our study was to evaluate the effect of the microvesicular steatosis of the donor liver on the postoperative outcomes after liver transplantation, with special regard to the incidence of EAD and PNF.
Methods Between May 2010 and July 2016, 290 patients underwent liver transplantations at the University Hospital Aachen. Only patients with pre-reperfusion liver biopsies at the time of transplantation were included in this analysis. Patients with missing data on donor histology were excluded. Furthermore, sixteen patients with combined kidney-liver transplantation, living-donor liver transplantation and split liver transplantation were excluded. Finally, we included 94 patients in this retrospective analysis. Liver biopsies were obtained during organ procurement and examined by the pathologist at the Institute of Pathology at the University Hospital Essen. Steatosis of the liver biopsies was determined on HE- and OROstained sections. Microvesicular steatosis was defined as at least one, usually numerous small lipid droplets smaller in size than the nucleus and not displacing the nucleus.[14] Surgical techniques as well as intraoperative and postoperative care were standardized. All liver transplantations were performed with an extracorporeal veno-venous/porto-systemic bypass as previously described.[15] The initial immunosuppression consisted of induction therapy with basiliximab (20 mg intraoperatively and on postoperative day [POD] 4), tacrolimus (trough level 10 µg/L), and corticosteroids (250 mg intraoperatively, 1 mg/kg on POD 1, and subsequent tapering). The following data of the recipients were collected: gender, age, etiology of disease and lab-MELD score. The following donor data were examined: gender, age, body mass index (BMI), CIT, bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH), creatinine level, grade of microand macrovesicular liver steatosis and length of intensive care unit (ICU) stay. The extended donor criteria were defined according to the German Medical Association: bilirubin >3 mg/dL, AST or ALT >150 U/L, age >65 years, ICU stay >7 days, BMI >30 kg/m2, or serum sodium concentration >165
mmol/L.[16] Furthermore, operative time, transfusion requirement, warm ischemic time (WIT) and type of organ allocation were analyzed. The outcome of liver transplantation was evaluated by the following parameters: length of ICU stay, duration of hospitalization, 30-day and 1-year patient survival, 30day and 1-year graft survival, and incidence of EAD and PNF. EAD was defined as follows: bilirubin ≥10 mg/dL on POD 7 and/or INR ≥1.6 on POD 7 and/or AST or ALT >2000 U/L within the first 7 days.[6] According to specifications of Eurotransplant, PNF was defined as re-transplantation or death within 7 days after liver transplantation. The incidence of rejections, postoperative acute renal failure requiring continuous renal replacement therapy and postoperative liver enzyme and creatinine values were also analyzed. Laboratory values were measured preoperatively (pre), immediately postoperatively (post), 24 hours postoperatively (POD 1) and on PODs 3, 7 and 14. Acute renal failure was defined as an increase in serum creatinine of more than 50% combined with oliguria, anuria or the need for renal replacement therapy on PODs 1-14. The patient follow-up period ended in August 2016. At that time, the mean follow-up was 856 days and 73 patients had been followed for at least one year.
Statistical analysis Statistical analyses were performed with SPSS statistical software (IBM®, SPSS® Statistics 20, Chicago, IL, USA) using the Chi-square test or the Fisher,s exact test for qualitative variables and the Kruskal-Wallis-Test or the univariate ANOVA for continuous variables. For continuous variables, the results are presented as median and range. The Kaplan-Meier method and the log-rank test were used to estimate and compare observed graft and patient survival. A two-sided P value of <0.05 was considered significant.
Results The patient cohort was first divided into three groups according to the grade of microvesicular steatosis (MiS) of the donor liver regardless of the degree of macrovesicular steatosis. Twenty-seven patients belonged to the MiS <30% group. The MiS 30%-60% group included 41 patients. Twenty-six patients belonged to the MiS >60% group.
Recipient characteristics The recipient characteristics did not differ significantly between the three groups. The median age was 58 years in the MiS <30% group, 54 in the MiS 30%-60% group and 57 in the MiS >60% group. The majority of the patients were male (81% in the MiS <30% group, 68% in the MiS 30%-60% group and 65% in the MiS >60%
618 • Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com
Liver transplantation and microvesicular steatosis
group). The median lab-MELD score was 15 in the MiS <30% group and 16 in the other two groups. The primary causes for liver transplantation were hepatocellular carcinoma (37%, 22% and 31%, respectively) and alcohol-induced cirrhosis (26%, 34% and 23%, respectively). The recipient demographics are shown in Table 1.
Donor characteristics The median BMI was 28 kg/m2 in all groups. The median donor age was 66 years in the MiS <30% group, 50 years in the MiS 30%-60% group and 59 years in the MiS >60% group. The median CIT was 460 minutes in the MiS <30% group, 482 minutes in the MiS 30%60% group and 465 minutes in the MiS >60% group. Fifty-nine percent of the organs were allocated by an extended allocation procedure in the MiS <30% group, 68% in the MiS 30%-60% group and 58% in the MiS >60% group. The grade of macrovesicular steatosis differed significantly between the three groups. The MiS <30% and MiS >60% groups had a median degree of 15%. In the MiS 30%-60% group, donor livers had a median degree of 30% (P=0.043). Table 2 shows donor characteristics. Intraoperative data The median WITs in the different groups were 40, 40 and 41 minutes, respectively. The patients in all three groups had a median intraoperative requirement of 6 units packed cell. Fifteen units fresh frozen plasma were used in the MiS <30% group, 10 in the MiS 30%-60% group and 12 in the MiS >60% group. The intraoperative data are shown in Table 3.
Table 2. Donor characteristics MiS <30% (n=27) 28 (23-50) 66 (34-74) 460 (355-600)
MiS 30%60% (n=41) 28 (19-40) 50 (22-80) 482 (265-780)
MiS >60% (n=26) 28 (21-47) 59 (22-83) 465 (311-588)
P value 0.172 0.747 0.400
Age >65 yr ICU stay >7 d AST or ALT >150 U/L Bilirubin >3 mg/dL Na >165 mmol/L BMI >30 kg/m2 Macrovesicular steatosis (%)
13 (48%) 14 (52%) 9 (33%) 2 (7%) 2 (7%) 12 (44%) 15 (0-90)
14 (34%) 7 (17%) 10 (24%) 0 3 (7%) 14 (34%) 30 (0-80)
8 (31%) 3 (12%) 9 (35%) 1 (4%) 4 (15%) 10 (38%) 15 (0-40)
0.400 0.002 0.652 0.154 0.486 0.712 0.043
Extended allocation
16 (59%) 28 (68%)
Characteristics BMI (kg/m2) Age (yr) Cold ischemic time (min) Extended donor criteria
15 (58%) 0.405
Table 3. Intraoperative data Variables Packed cell (U) Fresh frozen plasma (U) Platelet concentrate (U)
MiS <30% (n=27) 6 (0-28) 15 (10-48)
MiS 30%-60% (n=41) 6 (2-16) 10 (7-20)
0 (0-4)
0 (0-4)
Warm ischemic time 40 (33-67) 40 (20-56) (min)
MiS >60% P value (n=26) 6 (2-36) 0.252 12 (6-50) 0.096 1 (0-3)
0.996
41 (35-60) 0.496
Table 4. Postoperative data Table 1. Recipient characteristics Characteristics Age (yr) Gender (M/F) Indication for LT Acute liver failure Alcohol-induced cirrhosis HCC PSC/PBC Graft failure HCV/HBV NASH cirrhosis Other Lab-MELD Lab-MELD ≥30
MiS <30% (n=27) 58 (19-69) 22/5
MiS 30%-60% MiS >60% (n=41) (n=26) 54 (44-68) 57 (26-63) 28/13 17/9
1 (4%) 4 (10%) 7 (26%) 14 (34%)
1 (4%) 6 (23%)
10 (37%) 9 (22%) 4 (15%) 2 (5%) 1 (4%) 2 (5%) 2 (7%) 5 (12%) 1 (4%) 2 (5%) 1 (4%) 3 (7%) 15 (7-40) 16 (6-34) 4 (15%) 2 (5%)
8 (31%) 4 (15%) 0 2 (8%) 0 5 (19%) 16 (6-34) 3 (12%)
Variables P value 0.669 0.386 0.638
0.980 0.635
HCC: hepatocellular carcinoma; PSC: primary sclerosing cholangitis; PBC: primary biliary cirrhosis; HCV: hepatitis C virus; HBV: hepatitis B virus; NASH: nonalcoholic steatohepatitis; MELD: model for endstage liver disease.
Early allograft dysfunction Primary nonfunction Rejection Mild Moderate Severe CVVH Renal failure ICU stay (d) Hospital stay (d) 30-day mortality 1-year mortality 30-day re-transplantation 1-year re-transplantation
MiS <30% (n=27) 13 (48%) 1 (4%)
MiS 30%-60% MiS >60% P value (n=41) (n=26) 20 (49%) 7 (27%) 0.157 4 (10%)
6 (22%) 5 (12%) 0 0 1 (4%) 1(2%) 4 (15%) 9 (22%) 9 (33%) 12 (29%) 4 (2-113) 4 (2-178) 28 (13-113) 25 (13-178) 0 0 1/18 (6%) 4/33 (12%) 2 (7%) 5 (12%) 2/18 (11%)
5/33 (15%)
0 7 (27%) 1 (4%) 0 1 (4%) 4 (15%) 5 (2-22) 24 (15-72) 0 2/22 (9%) 0
0.269 0.339
0.120 0.305 0.349 0.598 1.000 0.882 0.197
1/22 (5%) 0.566
CVVH: continuous venovenous hemofiltration.
Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 619
Hepatobiliary & Pancreatic Diseases International
Postoperative data The median length of hospital stay after liver transplantation was 28 days in the MiS <30% group, 25 days in the MiS 30%-60% group and 24 days in the MiS >60% group. The patients in the MiS <30% and MiS 30%-60% groups had a median ICU stay of 4 days after liver transplantation. Patients in the MiS >60% group had a median ICU stay of 5 days. The incidence of EAD and PNF did not differ significantly in the different groups (P=0.157 and P=0.269) (Table 4). The MiS <30% group had an incidence of EAD of 48%. Forty-nine percent of patients in the MiS 30%-60% group developed EAD compared to 27% in the MiS >60% group. The most frequent criterion leading to the diagnosis of EAD was elevated liver enzymes within the first POD 7. We observed 5 cases of PNF. One occurred in the MiS <30% group and 4 in the MiS 30%-60% group. Significant differences of the postoperative laboratory values could only be observed for AST and ALT immediately after surgery and on POD 1. The median AST concentrations immediately after surgery were significantly higher in the MiS 30%-60% group [1313 vs 1191 U/L (MiS <30%) and 931 U/L (MiS >60%), P=0.013]. On POD 1, the
MiS <30% group had the highest concentration of AST [1129 vs 768 U/L (MiS 30%-60%) and 524 U/L (MiS >60%), P=0.015)(Fig. 1A). The ALT concentration immediately after surgery was significantly higher in the MiS >60% group (628 U/L) than in the MiS <30% (522 U/L) and the MiS 30%-60% groups (536 U/L) (P=0.041)(Fig. 1B). On POD 3-14, there were no differences in the median aminotransferase values between three groups. The grade of MiS was not related to bilirubin, GLDH or creatinine levels during the observation period. The incidence of acute renal failure and need for renal replacement therapy was not significantly different between three groups. All patients who required renal replacement therapy recovered without the need for permanent dialysis. Creatinine values at 6 months after liver transplantation were not significantly different between the three groups (P=0.292). The number of rejections was not different between the groups (P=0.339). The 30-day graft survival was 92.6% in the MiS <30% group, 87.8% in the MiS 30%-60% group and 100% in the MiS >60% group (P=0.187) (Fig. 2A). The 1-year graft survival was 89.5% in the MiS <30% group, 85.3%
Fig. 1. Postoperative ALT and AST values. A, B: aminotransferase values of all grafts. C, D: aminotransferase values after exclusion of the grafts with macrovesicular steatosis.
620 • Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com
Liver transplantation and microvesicular steatosis
in the MiS 30%-60% group and 95.5% in the MiS >60% group (P=0.481) (Fig. 2B). In the MiS <30% group, two re-transplantations were performed, one because of ischemic type biliary lesion (ITBL) and one because of PNF. All 5 re-transplantations in the MiS 30%-60% were necessary because of PNF. In the MiS >60% group, one re-transplantations was performed because of HCV recurrence. The 30-day patient survival rates were 100% in all groups. The 1-year patient survival rates were 94.4% in the MiS <30% group, 87.9% in the MiS 30%-60% group and 90.9% in the MiS >60% group (P=0.748) (Fig. 2C). In a second step we excluded all donor livers with a degree of macrovesicular steatosis of more than 10% to make sure that the degree of macrovesicular steatosis did not influence our results. Fifteen patients still belonged to the MiS <30% group and to the MiS 30%-60% group. The MiS >60% group included 14 patients. After Table 5. Postoperative data (liver grafts with macrovesicular steatosis >10% excluded) Variables Early allograft dysfunction Primary nonfunction Rejection Mild Moderate Severe CVVH Renal failure ICU stay (d) Hospital stay (d) 30-day mortality 1-year mortality 30-day re-transplantation 1-year re-transplantation
MiS <30% MiS 30%-60% MiS >60% P value (n=15) (n=15) (n=14) 3 (20%) 3 (20%) 1 (7%) 0.668 0
0
2 (13%) 4 (27%) 0 0 1 (7%) 0 2 (13%) 2 (13%) 4 (27%) 4 (27%) 4 (2-21) 4 (3-18) 25 (15-57) 25 (13-55) 0 0 0 1/12 (8%) 1 (7%) 1 (7%) 1/10 (10%) 1/12 (8%)
CVVH: continuous venovenous hemofiltration.
0 2 (14%) 1 (7%) 0 1 (7.1%) 2 (14%) 4 (2-10) 28 (15-55) 0 0 0 0
1.000 0.715
1.000 0.734 0.457 0.740 1.000 1.000 1.000 0.750
exclusion of the grafts with macrovesicular steatosis we could not observe differences in matters of the previous analysis. Table 5 provides the results of the postoperative data. The incidence of EAD and PNF as well as the number of re-transplantation and mortality did not differ significantly between the three groups. The only difference we observed after exclusion of the grafts with macrovesicular steatosis was the course of the postoperative aminotransferase values. In contrast to the first analysis, we could not observe significant differences between the three groups (Fig. 1C, D) immediate after surgery (AST, P=0.108; ALT, P=0.623) and on POD 1 (AST, P=0.386; ALT, P=0.538).
Discussion The aim of our study was to examine the influence of donor liver microvesicular steatosis on postoperative outcomes after liver transplantation. Several studies[4, 5, 8, 9] have investigated the effect of donor liver steatosis on patient outcome after liver transplantation. However, only inconsistent data existed and whether micro- or macrovesicular steatosis is of more importance remained unclear. On the one hand, the lack of consistency among various studies was caused by different parameters and endpoints analyzed. On the other hand, there was an enormous variability in definitions of types and amounts of steatosis. Furthermore, the formation of groups (micro- or macrovesicular steatosis) for statistical analysis is difficult, because most of the liver grafts offer both types of steatosis. Sharkey et al described an overlap between the different groups.[17] Therefore, we performed an analysis in two steps. First, the patient cohort was divided into groups according to the grade of microvesicular steatosis regardless of the degree of macrovesicular steatosis. In a second step, we excluded grafts with a degree of macrovesicular steatosis of more than 10% to make sure that the degree of macrovesicular steatosis did not influence our results. Most studies[18-20] evaluated the effect of macrovesicular
Fig. 2. The graft and patients survival. Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 621
Hepatobiliary & Pancreatic Diseases International
steatosis, even though microvesicular steatosis is considered to be a more serious condition, often associated with impaired mitochondrial beta-oxidation and, therefore, a less favorable prognosis.[11] The main concern with using donor organs with steatosis is a higher incidence of EAD and PNF with consequently, early re-transplantation.[6, 7, 21] We did not observe significant differences between the three groups with regard to the incidence of EAD. The MiS <30% and MiS 30%-60% groups had significantly higher peaks of AST immediately postoperative and on POD 1 (Fig. 1A, B), leading to a discreet higher number of EAD in the MiS <30% and the MiS 30%-60% groups. ALT concentration immediately postoperative was significant higher in the MiS >60% group, but without an effect on the rate of EAD. After exclusion of the liver grafts with macrovesicular steatosis, there were no differences of the postoperative aminotransferase values between the three groups (Fig. 1C, D) and no effect on the rate of EAD. Afonso et al[8] made the same observations in a retrospective analysis of 48 liver transplant patients. Grafts without microvesicular steatosis, with microvesicular steatosis <50% and >50% were compared, and no influence on initial liver function after liver transplantation was found (P=0.547). Sharkey et al[17] identified two subgroups of microsteatosis, termed high-grade and low-grade microsteatosis. Low-grade microsteatosis was defined as several small vesicles that neither filled the cell cytoplasm nor caused cell enlargement. High-grade microsteatosis presented many small vesicles that filled the cell cytoplasm with cell enlargement. They revealed that the presence of highgrade microsteatosis was more likely to be associated with delayed graft function in the postoperative period and that the amount of steatosis is of less importance. It should be noted that postoperative liver function was only evaluated by serum lactate level. Therefore, their study suggested that the excess in poor patient outcomes observed in association with macrosteatosis in other studies was actually related to the subgroup with high-grade microsteatosis, rather than to the amount of microsteatosis per se. Cieślak et al[22] did a retrospective analysis of 269 liver transplantations. They found that the risk of EAD was significantly related to hepatic microvesicular steatosis (P<0.021). A 50% increased risk of EAD was equivalent to a 12% increase in the extent of steatosis. Yoong et al[23] confirmed the negative effect of microsteatosis on postoperative liver function. They analyzed the outcome of 116 patients after re-liver transplantation and suggested that severe donor liver steatosis, of the microvesicular type, involving more than 66% of hepatocytes was associated with a significantly higher rate of EAD (P<0.01). In our cohort, the number of PNF cases did not differ significantly between the groups. Fishbein et al[9] made
the same observation. The grade of microvesicular steatosis did not affect the number of PNF cases. Interestingly, patient and graft survival in the MiS <30% group was not different from that in the MiS 30%-60% or >60% groups. Fishbein et al made the same observation in their patient cohort. The 1-year patient and graft survival rates were 80% and 72.5%, without any differences to the overall population.[9] Afonso et al[8] confirmed these results, in that, within their patients, collective microvesicular steatosis had no impact on 30-day mortality (P=0.380). In contrast to our results, Yoong et al found a worse outcome after re-liver transplantation. All grafts with severe microvesicular steatosis failed, following a median survival of 1.5 months.[23] Another important topic is the assessment of donor liver fat because it is a difficult task for the transplant team.[24] The histological analysis by a pathologist is the gold standard to assess liver steatosis.[25, 26] Liver steatosis >30% belongs to the extended donor criteria assessed by the German Medical Association.[16] However, McCormack et al showed that liver biopsy at the time of procurement for liver transplantation is rarely performed.[27] Only 23% of liver transplant recipients in the United Network for Organ Sharing had a liver donor biopsy recorded. We made the same observation in our transplant center. We could only include 32% of our collective liver transplantation patients because of missing donor histology. Furthermore, the staining technique plays an important role because it could affect the grading of steatosis.[28] Lo et al[29] showed that HE-stained frozen biopsy overestimates microsteatosis but underestimates macrosteatosis, when compared with permanent sections using a more specific staining modality. El-Badry et al[26] revealed that quantification of liver steatosis in histological sections is strongly observer-dependent, not reproducible, and does not correlate with the computerized estimation. Therefore, they advocate that the current standards of assessment and the clinical relevance of liver steatosis for liver surgery and transplantation should be challenged. Some limitations exist concerning the evaluation of our data. First, this analysis was performed retrospectively. Furthermore, the number of patients was relatively small. Multivariate analyses in larger patient collectives need to be performed to categorize the impact of donor microvesicular steatosis, within the context of other marginal donor criteria. In conclusion, microvesicular steatosis in donor livers has no negative effect on the postoperative outcomes after liver transplantation. Based on our findings, livers with either mild or severe microsteatosis can safely be transplanted. Contributors: AA, NU and SM proposed the study. AA, UTF, SW, KD, HM and APH collected and analyzed the data. AA and
622 • Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com
Liver transplantation and microvesicular steatosis
mann N, et al. Liver steatosis in pre-transplant liver biopsies SM wrote the manuscript. All authors revised the manuscript critically. AA is the guarantor. can be quantified rapidly and accurately by nuclear magnetic Funding: None. resonance analysis. Virchows Arch 2017;470:197-204. Ethical approval: This study was approved by the Ethics Com- 15 Mossdorf A, Ulmer F, Junge K, Heidenhain C, Hein M, Temmittee of the RWTH Aachen University Hospital. izel I, et al. Bypass during liver transplantation: anachronism Competing interest: No benefits in any form have been received or revival? Liver transplantation using a combined venoveor will be received from a commercial party related directly or nous/portal venous bypass-experiences with 163 liver transindirectly to the subject of this article. plants in a newly established liver transplantation program. Gastroenterol Res Pract 2015;2015:967951. 16 Schrem H, Reichert B, Frühauf N, Kleine M, Zachau L, Becker T, et al. Extended donor criteria defined by the German References Medical Association: study on their usefulness as prognostic 1 Nickkholgh A, Weitz J, Encke J, Sauer P, Mehrabi A, Büchler model for early outcome after liver transplantation. Chirurg MW, et al. Utilization of extended donor criteria in liver trans2012;83:980-988. plantation: a comprehensive review of the literature. Nephrol 17 Sharkey FE, Lytvak I, Prihoda TJ, Speeg KV, Washburn WK, Dial Transplant 2007;22:viii29-viii36. Halff GA. High-grade microsteatosis and delay in hepatic 2 Busuttil RW, Farmer DG, Yersiz H, Hiatt JR, McDiarmid SV, function after orthotopic liver transplantation. Hum Pathol Goldstein LI, et al. Analysis of long-term outcomes of 3200 2011;42:1337-1342. liver transplantations over two decades: a single-center experi- 18 Gwiasda J, Schrem H, Klempnauer J, Kaltenborn A. Identifyence. Ann Surg 2005;241:905-918. ing independent risk factors for graft loss after primary liver 3 Tector AJ, Mangus RS, Chestovich P, Vianna R, Fridell JA, transplantation. Langenbecks Arch Surg 2017;402:757-766. Milgrom ML, et al. Use of extended criteria livers decreases 19 Kulik U, Lehner F, Klempnauer J, Borlak J. Primary non-funcwait time for liver transplantation without adversely impacting tion is frequently associated with fatty liver allografts and high posttransplant survival. Ann Surg 2006;244:439-450. mortality after re-transplantation. Liver Int 2017;37:1219-1228. 4 Marsman WA, Wiesner RH, Rodriguez L, Batts KP, Porayko 20 Choi WT, Jen KY, Wang D, Tavakol M, Roberts JP, Gill RM. MK, Hay JE, et al. Use of fatty donor liver is associated with Donor liver small droplet macrovesicular steatosis is associdiminished early patient and graft survival. Transplantation ated with increased risk for recipient allograft rejection. Am J 1996;62:1246-1251. Surg Pathol 2017;41:365-373. 5 Adam R, Reynes M, Johann M, Morino M, Astarcioglu I, Kaf21 López-Navidad A, Caballero F. Extended criteria for organ acetzis I, et al. The outcome of steatotic grafts in liver transplanceptance. Strategies for achieving organ safety and for increastation. Transplant Proc 1991;23:1538-1540. ing organ pool. Clin Transplant 2003;17:308-324. 6 Olthoff KM, Kulik L, Samstein B, Kaminski M, Abecassis M, 22 Cieślak B, Lewandowski Z, Urban M, Ziarkiewicz-Wróblewska Emond J, et al. Validation of a current definition of early alB, Krawczyk M. Microvesicular liver graft steatosis as a risk lograft dysfunction in liver transplant recipients and analysis factor of initial poor function in relation to suboptimal donor of risk factors. Liver Transpl 2010;16:943-949. parameters. Transplant Proc 2009;41:2985-2988. 7 Bzeizi KI, Jalan R, Plevris JN, Hayes PC. Primary graft dys23 Yoong KF, Gunson BK, Neil DA, Mirza DF, Mayer AD, Buckfunction after liver transplantation: from pathogenesis to preels JA, et al. Impact of donor liver microvesicular steatosis vention. Liver Transpl Surg 1997;3:137-148. on the outcome of liver retransplantation. Transplant Proc 8 Afonso RC, Saad WA, Parra OM, Leitão R, Ferraz-Neto BH. 1999;31:550-551. Impact of steatotic grafts on initial function and prognosis af24 McCormack L, Dutkowski P, El-Badry AM, Clavien PA. Liver ter liver transplantation. Transplant Proc 2004;36:909-911. transplantation using fatty livers: always feasible? J Hepatol 9 Fishbein TM, Fiel MI, Emre S, Cubukcu O, Guy SR, Schwartz 2011;54:1055-1062. ME, et al. Use of livers with microvesicular fat safely expands 25 Silva MA. Putting objectivity into assessment of steatosis. the donor pool. Transplantation 1997;64:248-251. Transplantation 2009;88:620-621. 10 Hu KQ, Kyulo NL, Esrailian E, Thompson K, Chase R, Hillebrand DJ, et al. Overweight and obesity, hepatic steatosis, 26 El-Badry AM, Breitenstein S, Jochum W, Washington K, Paradis V, Rubbia-Brandt L, et al. Assessment of hepatic steatosis and progression of chronic hepatitis C: a retrospective study by expert pathologists: the end of a gold standard. Ann Surg on a large cohort of patients in the United States. J Hepatol 2009;250:691-697. 2004;40:147-154. 11 Fromenty B, Berson A, Pessayre D. Microvesicular steatosis 27 McCormack L, Petrowsky H, Jochum W, Mullhaupt B, Weber M, Clavien PA. Use of severely steatotic grafts in liver and steatohepatitis: role of mitochondrial dysfunction and liptransplantation: a matched case-control study. Ann Surg id peroxidation. J Hepatol 1997;26:13-22. 2007;246:940-948. 12 Angele MK, Rentsch M, Hartl WH, Wittmann B, Graeb C, Jauch KW, et al. Effect of graft steatosis on liver function 28 Selzner M, Clavien PA, et al. Fatty liver in liver transplantation and surgery. Semin Liver Dis 2001;21:105-113. and organ survival after liver transplantation. Am J Surg 29 Lo IJ, Lefkowitch JH, Feirt N, Alkofer B, Kin C, Samstein B, 2008;195:214-220. et al. Utility of liver allograft biopsy obtained at procurement. 13 Verran D, Kusyk T, Painter D, Fisher J, Koorey D, Strasser S, Liver Transpl 2008;14:639-646. et al. Clinical experience gained from the use of 120 steatotic donor livers for orthotopic liver transplantation. Liver Transpl Received February 10, 2017 2003;9:500-505. 14 Bertram S, Myland C, Swoboda S, Gallinat A, Minor T, LehAccepted after revision June 23, 2017 Hepatobiliary Pancreat Dis Int，Vol 16，No 6 • December 15，2017 • www.hbpdint.com • 623