Donor selection for adult-to-adult living donor liver transplantation: well begun is half done. Transplantation. 2013;95:501-506. [PMID: 23128999 DOI: 10.1097/tp.0b013e318274aba1]

A Comparative Study of Ultrasound Attenuation Imaging, Controlled Attenuation Parameters, and Magnetic Resonance Spectroscopy for the Detection of Hepatic Steatosis

OBJECTIVES

To investigate the methodology and clinical application of ultrasound attenuation imaging (ATI) and comparative analyze the diagnostic performance of ATI and controlled attenuation parameters (CAP) for detecting and grading hepatic steatosis.

METHODS

A total of 159 patients with NAFLD were prospectively enrolled. CAP and ATI examinations were performed within a week before proton magnetic resonance spectroscopy (¹ H-MRS). Ten liver attenuation coefficient (AC) measurements by ATI were obtained in each patient. The interclass correlation coefficients (ICCs) of the intraobserver consistencies and the ICCs between the median of the first two through the first nine measurements and all 10 measurements were calculated. The correlations between ¹ H-MRS, CAP, biological data, and ATI were evaluated. The significant factors associated with ATI and the diagnostic performance of ATI and CAP for detecting hepatic steatosis was evaluated.

RESULTS

The median value of AC for detecting hepatic steatosis was 0.831 dB/cm/MHz. For the intraobserver consistency of ATI, the ICC was 0.931. Compared with 10 measurements, a minimum of four ATI measurements was required. The correlation of AC with hepatic fat fraction (HFF) was significantly higher than that of CAP (0.603 vs 0.326, P = .0015). The HFF and triglyceride (TG) were the significant factors for the ATI. The area under the receiver operating characteristics (ROC) curves of ATI and CAP were 0.939 and 0.788 for detecting ≥10% hepatic steatosis; 0.751 and 0.572 for detecting >33% hepatic steatosis. The cutoff values of ATI and CAP were 0.697 dB/cm/MHz and 310 dB/m for detecting ≥10% hepatic steatosis; 0.793 dB/cm/MHz and 328 dB/m for detecting >33% hepatic steatosis. The sensitivity of ATI and CAP were 85.92% and 52.11% for detecting ≥10% hepatic steatosis; 87.50% and 82.14% for detecting >33% hepatic steatosis. The specificity of ATI and CAP were 94.12% and 100% for detecting ≥10% hepatic steatosis; 54.37% and 43.69% for detecting >33% hepatic steatosis.

CONCLUSIONS

ATI technology showed excellent intraobserver consistency and the optimal minimum number of ATI measurements was 4. ATI is a promising noninvasive, quantitative and convenient tool for assessing hepatic steatosis.

High-resolution MR imaging with gadoxetate disodium for the comprehensive evaluation of potential living liver donors

OBJECTIVE

Several major transplantation centers have used composite multimodality evaluation for the preoperative evaluation of potential living liver donors. This approach can be time-consuming and, although rare, can cause complications. We aimed to demonstrate the clinical feasibility of our comprehensive preoperative MR protocol for the preoperative assessment of living liver donor candidates instead of composite multimodality evaluation.

MATERIALS AND METHODS

Thirty-five consecutive living liver donor candidates underwent multiphasic liver CT and comprehensive donor protocol MR examinations for preoperative evaluation in a single large-volume liver transplantation (LT) center. Three blinded abdominal radiologists reviewed the CT and MR images for vascular and biliary variations. The strength of agreement between CT and MR angiography was assessed using the kappa index. The detection rate of biliary anatomical variations was calculated. The sensitivity and specificity for detecting significant steatosis (>5%) were calculated. The estimated total volume and right lobe volumes measured by MR volumetry were compared with the corresponding CT volumetry measurements using the intraclass correlation coefficient (ICC).

RESULTS

Among the 35 patients, 26 underwent LT. The measurement of agreement showed a moderate to substantial agreement between CT and MR angiography interpretations (kappa values, 0.47-0.79; p < 0.001). Combining T2-weighted and T1-weighted MR cholangiography techniques detected all biliary anatomical variations in 9 of the 26 patients. MR-proton density fat fraction showed a sensitivity of 100% (3/3) and a specificity of 91.3% (21/23) for detecting pathologically determined steatosis (>5%). MR volumetry reached an excellent agreement with CT volumetry (reviewers 1 and 2: ICC, 0.92; 95% CI, 0.84-0.96).

CONCLUSION

Our one-stop comprehensive liver donor MR imaging protocol can provide complete information regarding hepatic vascular and biliary anatomies, hepatic parenchymal quality, and liver volume for living liver donor candidates and can replace composite multimodality evaluation.

A systematic review of auxiliary liver transplantation of small for size grafts in patients with chronic liver disease

Background & Aims

The shortage of liver grafts continues to worsen. Because the expanded use of small-for-size grafts (SFSGs) would substantially alleviate this shortage, we aimed to analyse the available knowledge on auxiliary liver transplantation (ALT) with SFSGs in patients with chronic liver disease (CLD) to identify opportunities to develop ALT with SFSGs in patients with CLD.

Methods

This is a systematic review on ALT using SFSGs in patients with CLD. The review was completed by updates obtained from the authors of the retained reports.

Results

Heterotopic ALT was performed in 26 cases between 1980 and 2017, none for SFGS stricto sensu, and auxiliary partial orthotopic liver transplantation (APOLT) in 27 cases (from 1999 to 2021), all for SFSG. In APOLT cases, partial native liver resection was performed in most of cases, whereas the second-stage remnant native liver hepatectomy was performed in 9 cases only. The median graft-to-body weight ratio was 0.55, requiring perioperative or intraoperative portal modulation in 16 cases. At least 1 complication occurred in 24 patients following the transplant procedure (morbidity rate, 89%). Four patients (4/27, 15%) died after the APOLT procedure. At the long term, 19 (70%) patients were alive and well at 13 months to 24 years (median, 4.5 years) including 18 with the APOLT graft in place and 1 following retransplantation.

Conclusions

Despite high postoperative morbidity, and highly reported technical variability, the APOLT technique is a promising technique to use SFSGs in patients with CLD, achieving satisfactory long-term results. The results need to be confirmed on a larger scale, and a standardised technique could lead to even better results.

Lay summary

At the cost of a high postoperative morbidity, the long-term results of APOLT for small-for-size grafts are good. Standardisation of the procedure and of portal modulation remain needed.

•

Using a small-for-size graft is a risk factor of small-for-size syndrome.

•

Auxiliary liver transplantation can be orthotopic or heterotopic.

•

In auxiliary transplantation, the remnant native liver prevents small-for-size syndrome.

•

Transplantation with a small-for-size graft requires individually tailored portal modulation.

•

Auxiliary liver transplantation might substantially increase the number of available grafts.

Increasing Living Donor Liver Transplantation Using Liver Paired Exchange

BACKGROUND

Living donor liver transplantation (LDLT) continues to be the primary modality of liver transplantation in Asia, but it accounts for about 5% of all liver transplantations in the US. ABO incompatibility is the primary reason motivated donors are declined. Although kidney paired exchanges are common, liver paired exchange (LPE) is still evolving in the US.

STUDY DESIGN

This is a retrospective review (between January 1, 2019, and July 31, 2021) of our initial experience with LPE.

RESULTS

A total of 10 LPEs (20 LDLTs) were performed during the study period. Seven LPEs were initiated by a nondirected O donor. The other 3 pair sets involved 1 ABO compatible and 1 ABO incompatible pair. Transplantations in a pair set were completed within a mean of 4.8 (range 1-14) days of each other. All 20 donors are doing well with no major complications at 12.7 (range 1-20) months. Seventeen of 20 recipients are alive and have good allograft function. One recipient died in the early postoperative period. Two late deaths of patients with functioning allografts were due to COVID-19 (at 8 months) and peritoneal carcinomatosis and gram-negative sepsis (at 9 months).

CONCLUSIONS

LPE is feasible in a high-volume LDLT center and is a useful option to increase LDLT by overcoming ABO incompatibility. Nondirected donors can be utilized to initiate an LPE.

Validation of Accuracy of Non-Invasive Imaging Methods (Magnetic Resonance Imaging (MRI) Fat Fraction Calculation and Computed Tomography (CT) Liver Attenuation Index) for Hepatic Graft Fat Quantification in Living Liver Transplant Donors

BACKGROUND Diagnosis of significant hepatic graft steatosis remains vital for success of any transplant program as it has an impact on donor morbidity and recipient survival. Even histopathological quantification faces limitations. The present study compared the diagnostic accuracy of CT-LAI and MRI fat fraction imaging with histopathological analysis for donor graft parenchymal fat quantification. MATERIAL AND METHODS CT-LAI and MR-FF values and histopathological fat quantification results of 273 patients were identified from electronic records of the author's institutes from September 2015 to April 2020. Data analysis was done using SPSS version 21.0. RESULTS Most participants were young with nearly equal sex distribution and significant number of overweight and obese patients. Moderate agreement and significant positive correlation were found between MR fat fraction (%) and biopsy-macrosteatosis (%). Diagnostic accuracy and negative predictive value of MRI for fat fraction calculation was high (95.24% and 98.07% for fat fraction of 10% threshold, respectively), and it further improved for fat fraction threshold of 15%. CONCLUSIONS MRI-based fat quantification calculation displayed near-perfect negative predictive values and very high diagnostic accuracy, suggesting that it can obviate the need for biopsy in patients with graft fat percentage <10% on MRI.

Circuitous Path to Live Donor Liver Transplantation from the Coordinator's Perspective

Background: The live donor liver transplantation (LDLT) process is circuitous and requires a considerable amount of coordination and matching in multiple aspects that the literature does not completely address. From the coordinators’ perspective, we systematically analyzed the time and risk factors associated with interruptions in the LDLT process. Methods: In this retrospective single center study, we reviewed the medical records of wait-listed hospitalized patients and potential live donors who arrived for evaluation. We analyzed several characteristics of transplant candidates, including landmark time points of accompanied live donation evaluation processes, time of eventual LDLT, and root causes of not implementing LDLT. Results: From January 2014 to January 2021, 417 patients (342 adults and 75 pediatric patients) were enrolled, of which 331 (79.4%) patients completed the live donor evaluation process, and 205 (49.2%) received LDLT. The median time from being wait-listed to the appearance of a potential live donor was 19.0 (interquartile range 4.0–58.0) days, and the median time from the appearance of the donor to an LDLT or a deceased donor liver transplantation was 68.0 (28.0–188.0) days. The 1-year mortality rate for patients on the waiting list was 34.3%. Presence of hepatitis B virus, encephalopathy, and hypertension as well as increased total bilirubin were risk factors associated with not implementing LDLT, and biliary atresia was a positive predictor. The primary barriers to LDLT were a patient’s critical illness, donor’s physical conditions, motivation for live donation, and stable condition while on the waiting list. Conclusions: Transplant candidates with potential live liver donors do not necessarily receive LDLT. The process requires time, and the most common reason for LDLT failure was critical diseases. Aggressive medical support and tailored management policies for these transplantable patients might help reduce their loss during the process.

Outcomes of Highly Selected Live Donors With a Future Liver Remnant Less Than or Equal to 30%: A Matched Cohort Study

BACKGROUND

The main concern with live donor liver transplantation (LDLT) is the risk to the donor. Given the potential risk of liver insufficiency, most centers will only accept candidates with future liver remnants (FLR) >30%. We aimed to compare postoperative outcomes of donors who underwent LDLT with FLR ≤30% and >30%.

METHODS

Adults who underwent right hepatectomy for LDLT between 2000 and 2018 were analyzed. Remnant liver volumes were estimated using hepatic volumetry. To adjust for between-group differences, donors with FLR ≤30% and >30% were matched 1:2 based on baseline characteristics. Postoperative complications including liver dysfunction were compared between the groups.

RESULTS

A total of 604 live donors were identified, 28 (4.6%) of whom had a FLR ≤30%. Twenty-eight cases were successfully matched with 56 controls; the matched cohorts were mostly similar in terms of donor and graft characteristics. The calculated median FLR was 29.8 (range, 28.0-30.0) and 35.2 (range, 30.1-68.1) in each respective group. Median follow-up was 36.5 mo (interquartile range, 11.8-66.1). Postoperative outcomes were similar between groups. No difference was observed in overall complication rates (FLR ≤30%: 32.1% versus FLR >30%: 28.6%; odds ratio [OR], 1.22; 95% confidence interval [CI], 0.46-3.27) or major complication rates (FLR ≤30%: 14.3% versus FLR >30%: 14.3%; OR, 1.17; 95% CI, 0.33-4.10). Posthepatectomy liver failure was rare, and no difference was observed (FLR ≤30%: 3.6% versus FLR >30%: 3.6%; OR, 1.09; 95% CI, 0.11-11.1).

CONCLUSION

A calculated FLR between 28% and 30% on its own should not represent a formal contraindication for live donation.

Non-alcoholic fatty liver disease and obesity among adult donors are major challenges to living donor liver transplantation: A single-centre experience

OBJECTIVES

Obesity and non-alcoholic fatty liver disease (NAFLD) are rampant in South East Asia. There is paucity of data exploring its' impact on donor suitability for living donor liver transplantation (LDLT). We aimed to describe and examine the factors related to non-utilization of potential donors in our LDLT programme.

METHODS

This is an analysis of prospectively collected data on potential donors for an adult LDLT programme, between January 2017 and December 2019.

RESULTS

Fifty-five donors for 33 potential recipients were evaluated. The mean age was 31.6 ± 8.5 years, 52.7% were female and the ethnic divisions were: Chinese (50.9%), Indian (25.5%) and Malay (23.6%). The mean body mass index (BMI) among potential donors was 25.1 ± 4.0 kg/m²; 25.5% of donors had normal BMI, 23.6% were overweight and 50.9% were obese. Using the CAP modality of Fibroscan®, we identified the following grades of hepatic steatosis: 36.6% S0, 19.5% S1, 2.4% S2 and 41.5% S3. The non-utilization rate of our donors was 74.5% (41/55) and the main reasons were significant hepatic steatosis and/or obesity. Compared to suitable donors, unsuitable donors had significantly greater mean BMI, mean CAP scores, higher rates of dyslipidaemia and NAFLD.

CONCLUSION

NAFLD and obesity represent major challenges to an emerging LDLT programme in Malaysia.

Outcomes of living liver donor candidate evaluations in the Living Donor Collective pilot registry

BACKGROUND

To gather information on long-term outcomes after living donation, the Scientific Registry of Transplant Recipients (SRTR) conducted a pilot on the feasibility of establishing a comprehensive donor candidate registry.

METHODS

A convenience sample of 6 US living liver donor programs evaluated 398 consecutive donor candidates in 2018, ending with the March 12, 2020, COVID-19 emergency.

RESULTS

For 333/398 (83.7%), the donor or program decided whether to donate; 166/333 (49.8%) were approved, and 167/333 (50.2%) were not or opted out. Approval rates varied by program, from 27.0% to 63.3% (median, 46%; intraquartile range, 37.3-51.1%). Of those approved, 90.4% were white, 57.2% were women, 83.1% were < 50 years, and 85.5% had more than a high school education. Of 167 candidates, 131 (78.4%) were not approved or opted out because of: medical risk (10.7%); chronic liver disease risk (11.5%); psychosocial reasons (5.3%); candidate declined (6.1%); anatomical reasons increasing recipient risk (26.0%); recipient-related reasons (33.6%); finances (1.5%); or other (5.3%).

CONCLUSIONS

A comprehensive national registry is feasible and necessary to better understand candidate selection and long-term outcomes. As a result, the US Health Resources and Services Administration asked SRTR to expand the pilot to include all US living donor programs.

Assessment of the global practice of living donor liver transplantation

Criteria that drive the selection and utilization of living liver donors are limited. Herein, the global availability of living donor liver transplantation (LDLT) and components of donor selection and utilization were assessed via an international survey. There were 124 respondents representing 41 countries, including 47 from Asia/Middle East (A/ME), 20 from Europe, and 57 from the Americas. Responses were obtained from 94.9% of countries with ≥10 LDLT cases/year. Most centers (82.3%) have defined donor age criteria (median 18-60 years), while preset recipient MELD cutoffs (median 18-30) were only reported in 54.8% of programs. Overall, 67.5% of programs have preset donor BMI (body mass index) ranges (median 18-30), and the mean acceptable macrosteatosis was highest for A/ME (20.2 ± 9.2%) and lowest for Americas (16.5 ± 8.4%, P = 0.04). Americas (56.1%) and European (60.0%) programs were more likely to consider anonymous donors versus A/ME programs (27.7%, P = 0.01). There were no differences in consideration of complex anatomical variations. Most programs (75.9%) perform donor surgery via an open approach, and A/ME programs are more likely to use microscopic arterial reconstruction. Despite variations in practice, key aspects of living donor selection were identified. These findings provide a contemporary reference point as LDLT continues to expand into areas with limited access to liver transplantation.

Lose Weight to Donate: Development of a Program to Optimize Potential Donors With Hepatic Steatosis or Obesity for Living Liver Donation

Background.

Living donor liver transplantation offers an attractive option to reduce the waitlist mortality. However, in recent years, the rising prevalence of obesity and nonalcoholic fatty liver disease has posed a serious threat to the donor pool while simultaneously increasing demand for liver transplant. To our knowledge, there have been no major published studies in the United States documenting a diet and exercise intervention to expand the living donor pool. Hereby, we established a pilot program called “Lose Weight to Donate” and present our initial experience.

Methods.

Our center instituted a remotely monitored diet and exercise pilot program to increase eligibility for living liver donation. Potential donors with any of the following were included: body mass index >30 kg/m², hepatic steatosis >5% on screening MRI, or isolated hypertension.

Results.

Over 19 mo, 7 individuals enrolled in the program of remote monitoring for at least 6–8 wk. Initial and follow-up abdominal MRI was performed in 5 of these individuals to assess steatosis, anatomy, and volume. Initial steatosis was highly variable (fat signal fraction range, 8%–26%). Follow-up MRI fat signal fraction values and hepatic volume all decreased to varying degrees. Ultimately, 2 of 7 individuals donated, whereas a third was approved, but the intended recipient was transplanted in the interim.

Conclusions.

These results indicate the feasibility of a remotely monitored program to expand donation in light of the rising incidence of hepatic steatosis and obesity.

Validating controlled attenuation parameter in the assessment of hepatic steatosis in living liver donors

INTRODUCTION

Hepatic steatosis (HS) negatively impacts transplant outcomes in living liver donors. To date, liver biopsy is preferred for HS evaluation. This study aims to evaluate the measurement of controlled attenuation parameter (CAP) as a diagnostic tool of HS in living liver donors.

METHODS

Candidates recruited to this study, conducted from April 2016 to February 2020, were potential donors who had undergone transient elastography using Fibroscan® and CAP measurements at liver segments VI and VII, followed by liver biopsy. The HS grades from liver biopsy were classified as S0 (<5%), S1 (5-33%), S2 (33-66%), and S3 (>66%). For CAP, they were S0 (≤218dB/m), S1 (218-249dB/m)), S2 (250-305dB/m)), and S3 (>305dB/m)). The CAP measurements were compared with the liver biopsy results.

RESULTS

Of the 150 potential donors [male, 73.3%; mean age, 30.0±7.0 years; body mass index (BMI), 24.7±3.5kg/m2], 92 (61.3%) had no or mild HS, while 58 (38.7%) and 10% had moderate to severe HS based on CAP and liver biopsy, respectively. Subjects with moderate to severe HS per CAP were mostly males (0.014), and had higher BMI (p = .006), alanine aminotransferase (ALT) (.001), gamma-glutamyl transferase (.026), and high-density lipoprotein (.008). On multivariate analysis, high ALT (OR, 1.051; 95% CI, 1.016-1.087; p = .004) was a predictor of significant HS. The sensitivity, specificity, positive and negative predictive values of CAP to detect significant HS were 93.3%, 67.4, 24.1%, and 98.9%, respectively.

CONCLUSION

The high sensitivity and negative predictive values of CAP make it a good screening test to exclude significant HS in potential living liver donors which, in turn, can help avoid unnecessary liver biopsies.

Safe use of right lobe living donor livers with moderate steatosis in adult-to-adult living donor liver transplantation: a retrospective study

Hepatic steatosis (HS) beyond a certain degree can jeopardize living donor (LD) safety, particularly in right lobe (RL) donors, making it a major obstacle for donor pool expansion in adult-to-adult living donor liver transplantation (ALDLT). From July 2004 to June 2016, 58 LDs donated their RLs despite having moderate HS (30%-50% steatosis) determined by intraoperative biopsy at a single center. We performed greedy matching to compare the outcomes of the donors and recipients of this group with those of LDs with no HS. The mean left lobe (LL) HS value in the 58 cases was 20.9 ± 12.4%, which was significantly lower than the mean RL HS value (38.8 ± 6.7%, P < 0.001). The mean ratio of the remnant LL to the total liver volume was 37.8 ± 2.2. No differences were observed in the postoperative liver function and donor and recipient morbidity and mortality rates. The liver regeneration rates in recipients and donors at 1 month, 6 months, and 1 year postoperatively did not differ significantly. The patient and graft survival rates of the recipients showed no differences. The use of well-selected RL grafts with moderate steatosis does not impair graft function, recipient outcomes, or donor safety.

Liver structural transformation after partial hepatectomy and repeated partial hepatectomy in rats: A renewed view on liver regeneration

BACKGROUND

The phenomenon of liver regeneration after partial hepatectomy (PH) is still a subject of considerable interest due to the increasing frequency of half liver transplantation on the one hand, and on the other hand, new surgical approaches which allow removal of massive space-occupying hepatic tumors, which earlier was considered as inoperable. Interestingly, the mechanisms of liver regeneration are extensively studied after PH but less attention is paid to the architectonics of the regenerated organ. Because of this, the question “How does the structure of regenerated liver differ from normal, regular liver?” has not been fully answered yet. Furthermore, almost without any attention is left the liver's structural transformation after repeated hepatectomy (of the re-regenereted liver).

AIM

To compare the architectonics of the lobules and circulatory bed of normal, re-generated and re-regenerated livers.

METHODS

The livers of 40 adult, male, albino Wistar rats were studied. 14 rats were subjected to PH - the 1^st study group (SG1); 10 rats underwent repeated PH – the 2^nd study group (SG2); 16 rats were subjected to sham operation - control group (CG); The livers were studied after 9 months from PH, and after 6 months from repeated PH. Cytological (Schiff reaction for the determination of DNA concen-tration), histological (H&E, Masson trichrome, CK8 Immunohistochemical marker, transparent slides after Indian Ink injection, ), morphometrical (hepatocytes areas, perimeters and ploidy) and Electron Microscopical (Scanning Electron Microscopy of corrosion casts) methods were used.

RESULTS

In the SG1 and SG2, the area of hepatocytes and their perimeter are increased compared to the CG (P < 0.05). However, the areas and perimeters of the hepatocytes of the SG₁ and SG₂ groups reveal a lesser difference. In regenerated (SG₁) and re-regenerated (SG₂) livers, the hepatocytes form the remodeled lobules, which size (300-1200 µm) exceeds the sizes of the lobules from CG (300-600 µm). The remodeled lobules (especially the “mega-lobules” with the sizes 1000-1200 µm) contain the transformed meshworks of the sinusoids, the part of which is dilated asymmetrically. This meshwork might have originated from the several portal venules (interlobular and/or inlet). The boundaries between the adjacent lobules (including mega-lobules) are widened and filled by connective tissue fibers, which gives the liver parenchyma a nodular look. In SG₂ the unevenness of sinusoid diameters, as well as the boundaries between the lobules (including the mega-lobules) are more vividly expressed in comparison with SG₁. The liver tissue of both SG₁ and SG₂ is featured by the slightly expressed ductular reaction.

CONCLUSION

Regenerated and re-regenerated livers in comparison with normal liver contain hypertrophied hepatocytes with increased ploidy which together with transformed sinusoidal and biliary meshworks form the remodeled lobulli.

Individualized biliary reconstruction techniques in autotransplantation for end-stage hepatic alveolar echinococcosis

BACKGROUND

Biliary reconstruction in ex vivo liver resection followed by autotransplantation (ERAT) for end-stage hepatic alveolar echinococcosis (HAE) remains the most challenging step, we present our experience with this complex procedure.

METHODS

A retrospective data analysis of 55 patients with end-stage HAE underwent ERAT, the biliary reconstruction techniques and short- and long-term outcomes were discussed.

RESULTS

All autografts were derived from the left lateral section after extensive ex vivo liver resection, multiple bile ducts were observed in 52 (94.5%) patients, and forty-four (80.0%) cases required ductoplasty. Biliary reconstruction was achieved with duct-to-duct anastomosis in 32 (58.2%) patients, Roux-en-Y hepaticojejunostomy (RYHJ) in 14 (25.5%) patients, and a combination of the two methods in 9 (16.4%) patients. Twenty (36.4%) patients had multiple anastomoses. Biliary leakage occurred in 8 (14.5%) patients postoperatively. Three (5.5%) patients died of liver failure, cerebral hemorrhage and intraabdominal bleeding. During a median of 31 months followed-up time, 3 (5.5%) patients developed anastomotic stricture, 1 of whom was treated by repeat RYHJ, while the others were managed with stenting.

CONCLUSIONS

With a well-designed plan and precise anastomosis, complex biliary reconstruction in ERAT can be performed with few biliary complications by a professional team.

Lifestyle Modification Leads to Spatially Variable Reduction in Hepatic Steatosis in Potential Living Liver Donors

The spatial variability of hepatic fat reduction in potential living liver donors with hepatic steatosis (HS) who undergo lifestyle modification has not been investigated. Here, we aimed to examine the intrasegmental and intersegmental variability of changes in liver attenuation on computed tomography (CT) in potential living liver donors with HS after diet modification and exercise. A total of 87 living liver donor candidates (30.5 ± 7.0 years; 74 males) with biopsy-proven macrovesicular fat (MaF) ≥10% were included. All underwent diet modification and exercise to improve HS, baseline and follow-up unenhanced CT scans, and liver biopsies. Attenuation and its variability (mean and standard deviation, respectively, in Hounsfield units) in segmental, lobar, superficial, deep, and whole areas of the liver were measured across 32 different regions of interest on both baseline and follow-up CT. At baseline, the right lobe and superficial areas of liver showed significantly lower and more variable attenuation than left lobe and deep areas. Greater variability was noted in patients with more severe HS. Mean interval changes in liver attenuation and variability before and after diet modification and exercise were 13.7 (range, -10.6 to 46.2) and 4.7 (1.6-10.6), respectively. The mean interval change in liver attenuation was significantly higher in the right lobe than in the left (14.7 versus 12.7; P < 0.001), and in superficial areas than in deep areas (14.0 versus 13.4; P = 0.02). Greater variability and larger interval changes in liver attenuation were noted in those who responded (≥20% decrease in MaF) to diet modification and exercise than in those who did not. In conclusion, potential living liver donors with HS show significant intrasegmental and intersegmental variability in hepatic fat reduction on CT before and after diet modification and exercise.

Utility of magnetic resonance proton density fat fraction technique in quantification of liver fat in living donors for liver transplantation

Background

Hepatic steatosis in living donors for liver transplantation causes morbidity of both donor and recipient. This study aims at evaluating magnetic resonance proton density fat fraction technique (MR PDFF) in quantitative evaluation of living donor’s hepatic steatosis compared to histopathology.

Results

The examined potential living liver donors’ liver biopsies revealed hepatic steatosis < 5% (grade 0) in 40 donors and 5–10% (grade 1) in 7 donors. MR PDFF technique with IDEAL sequence showed excellent results for prediction and quantitative evaluation of liver fat with sensitivity, specificity, and accuracy of 85.7%, 97.5%, and 95.7%, respectively, compared to histopathology (95% confidence interval 0.98–1.01). There was an excellent inter-reader agreement between both readers in estimation of MR liver fat fraction (r = 0.969 at 95% confidence interval 0.946–0.983).

Conclusion

Noninvasive hepatic MR PDFF technique with IDEAL sequence is a precise reliable technique for pre-operative quantitative assessment of hepatic steatosis in potential living liver donors.

Considerations of Ultrasound Scanning Approaches in Non-alcoholic Fatty Liver Disease Assessment through Acoustic Structure Quantification

Non-alcoholic fatty liver disease (NAFLD) is a risk factor for hepatic fibrosis and cirrhosis. Acoustic structure quantification (ASQ), based on statistical analysis of ultrasound echoes, is an emerging technique for hepatic steatosis diagnosis. A standardized measurement protocol for ASQ analysis was suggested previously; however, an optimal ultrasound scanning approach has not been concluded thus far. In this study, the suitability of scanning approaches for the ASQ-based evaluation of hepatic steatosis was investigated. Hepatic fat fractions (HFFs; liver segments VIII, III and VI) of 70 living liver donors were assessed with magnetic resonance spectroscopy. A clinical ultrasound machine equipped with a 3-MHz convex transducer was used to scan each participant using the intercostal, epigastric and subcostal planes to acquire raw data for estimating two ASQ parameters (C_m² and focal disturbance [FD] ratio) of segments VIII, III and VI, respectively. The parameters were plotted as functions of the HFF for calculating the values of the correlation coefficient (r) and probability value (p). The diagnostic performance of the parameters in discriminating between the normal and steatotic (≥5 and ≥10%) groups was also compared using receiver operating characteristic (ROC) curves. The C_m² and FD ratio values measured using the epigastric and subcostal planes did not correlate with the severity of hepatic steatosis. However, intercostal imaging exhibited a higher correlation between the ASQ parameters and HFF (r = -0.64, p < 0.001). The diagnostic performance of C_m² and FD ratio in detecting hepatic steatosis using intercostal imaging was also satisfactory (areas under ROC curves >0.8). Intercostal imaging is an appropriate scanning approach for ASQ analysis of the liver.

Experience and outcomes in living donor liver procurement using the water jet scalpel

BACKGROUND

The aim of the present study was to clarify treatment outcomes of living donor liver procurement using the water jet scalpel (WJS).

METHODS

This single-center, retrospective cohort study included 40 living donors who underwent liver procurement from January 2014 to December 2018. One living donor who underwent posterior segmentectomy was excluded. Clinical data and outcomes after surgery for 20 WJS donors and 19 Cavitron Ultrasonic Surgical Aspirator (CUSA) donors were compared.

RESULTS

Preoperative and excised graft data did not differ significantly between the WJS and CUSA groups. Operation time (P = 0.025) and parenchymal transection time (P = 0.007) were significantly shorter in the WJS group. There was no difference between the groups in terms of short-term outcomes after surgery. Multivariate analysis revealed that WJS offered significant advantages over CUSA in terms of shortening parenchymal transection time (P = 0.017).

CONCLUSION

Living donor liver procurement using WJS contributes to shortening of parenchymal transection time while maintaining the same level of safety as when using CUSA.

Assessment of hepatic steatosis by using attenuation imaging: a quantitative, easy-to-perform ultrasound technique

OBJECTIVES

To evaluate the diagnostic performance of attenuation imaging (ATI) in the detection of hepatic steatosis compared with a histopathology gold standard.

METHODS

We prospectively enrolled 108 consecutive patients (35 males; median age, 54.0 years) who underwent percutaneous liver biopsy for evaluation of diffuse liver disease between January 2018 and November 2018 in a tertiary academic center. Grayscale ultrasound examination with ATI was performed just before biopsy, and an attenuation coefficient (AC) was obtained from each patient. The degree of hepatic steatosis, fibrosis stage, and necroinflammatory activity were assessed on histopathologic examination. The significant factor associated with the AC was found by a linear regression analysis, and the diagnostic performance of the AC for the classification into each hepatic steatosis stage was evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

The distribution of hepatic steatosis grade on histopathology was 53/11/22/16/6 for none/mild (< 10%)/mild (≥ 10%)/moderate/severe steatosis, respectively. The area under the ROC curve, sensitivity, specificity, and optimal cutoff AC value for detection of hepatic steatosis ranged from 0.843-0.926, 74.5-100.0%, 77.4-82.8%, and 0.635-0.745, respectively. Multivariate analysis revealed that the degree of steatosis was the only significant determinant factor for the AC.

CONCLUSIONS

The AC from ATI provided good diagnostic performance in detecting the varying degrees of hepatic steatosis. The degree of steatosis was the only significant factor affecting the AC, whereas fibrosis and inflammation were not.

KEY POINTS

• Attenuation imaging (ATI) is based on two-dimensional grayscale ultrasound images that can incorporate into routine ultrasound examinations with less than 2 min of acquisition time. • ATI provided good diagnostic performance in detecting the varying degrees of hepatic steatosis with an area under the ROC curves ranging from 0.843 to 0.926, and there was no technical failure in this study indicating high applicability of this technique. • The degree of hepatic steatosis was the only significant factor affecting the result of ATI examination.

Quantitative Hepatic Fat Quantification in Non-alcoholic Fatty Liver Disease Using Ultrasound-Based Techniques: A Review of Literature and Their Diagnostic Performance

Non-alcoholic fatty liver disease is a condition that is characterized by the presence of >5% fat in the liver and affects more than one billion people worldwide. If adequate and early precautions are not taken, non-alcoholic fatty liver disease can progress to cirrhosis and death. The current reference standard for detecting hepatic steatosis is a liver biopsy. However, because of the potential morbidity associated with liver biopsies, non-invasive imaging biomarkers have been extensively investigated. Magnetic resonance imaging-based methods have proven accuracy in quantifying liver steatosis; however, these techniques are costly and have limited availability. Ultrasound-based quantitative imaging techniques are increasingly utilized because of their widespread availability, ease of use and relative cost-effectiveness. Several ultrasound-based liver fat quantification techniques have been investigated, including techniques that measure changes in the acoustic properties of the liver caused by the presence of fat. In this review, we focus on quantitative ultrasound approaches and their diagnostic performance in the realm of non-alcoholic fatty liver disease.

Liver paired exchange: Can the liver emulate the kidney?

Kidney paired exchange (KPE) constitutes 12% of all living donor kidney transplantations (LDKTs) in the United States. The success of KPE programs has prompted many in the liver transplant community to consider the possibility of liver paired exchange (LPE). Though the idea seems promising, the application has been limited to a handful of centers in Asia. In this article, we consider the indications, logistical issues, and ethics for establishing a LPE program in the United States with reference to the principles and advances developed from experience with KPE. Liver Transplantation 24 677-686 2018 AASLD.

Can negligible hepatic steatosis determined by magnetic resonance imaging-proton density fat fraction obviate the need for liver biopsy in potential liver donors?

The purpose of this study is to determine whether magnetic resonance (MR)-proton density fat fraction (PDFF) estimate of negligible hepatic fat percentage (<5%) can exclude significant hepatic steatosis (≥10%) in living liver donor candidates obviating the need for liver biopsy and to perform intraindividual comparisons between MR-PDFF techniques for hepatic steatosis quantification. In an ethics-approved retrospective study, 144 liver donor candidates with magnetic resonance spectroscopy (MRS) and 6-echo Dixon magnetic resonance imaging (MRI) between 2013 and 2015 were included. A subset of 32 candidates underwent liver biopsy. Hepatic fat percentage was determined using MR-PDFF and histopathology-determined fat fraction as the reference standard. A receiver operating characteristic analysis with positive predictive value, negative predictive value (NPV), sensitivity, and specificity was performed to discriminate between clinically significant steatosis (≥10%) or not (<10%) at MRS-PDFF and MRI-PDFF thresholds of 5% and 10%. Pearson correlation and Bland-Altman analyses between MRS-PDFF and MRI-PDFF were performed for intraindividual comparison of hepatic steatosis estimation. There was significant association between MRS-PDFF and MRI-PDFF with HP-FP. High NPV of 95% (95% confidence interval [CI], 78%-99%) and 100% (95% CI, 76%-100%) as well as an area under the curve of 0.90 (95% CI, 0.79-1.0) and 0.93 (95% CI, 0.84-1.0) were obtained with a cutoff threshold of 5% MRI-PDFF and MRS-PDFF, respectively, to exclude clinically significant steatosis (≥10%). Intraindividual comparison between MRS-PDFF and MRI-PDFF showed a Pearson correlation coefficient of 0.83. Bland-Altman analysis showed a mean difference of 1% with 95% limits of agreement between -1% and 3%. MR-PDFF estimate of negligible hepatic fat percentage (<5%) has sufficient NPV for excluding clinically significant hepatic steatosis (≥10%) in living liver donor candidates obviating the need for liver biopsy. It may be sufficient to acquire only the multiecho Dixon MRI-PDFF for hepatic steatosis estimation. Liver Transplantation 24 470-477 2018 AASLD.

Living donor liver transplantation: eliminating the wait for death in end-stage liver disease?

Adult-to-adult living donor liver transplantation (A2ALDLT), outside of Asia, remains an important yet underutilized gift of life. For patients with end-stage liver disease, A2ALDLT is a proven transplantation option, with lower waiting list mortality and suffering, and equivalent or better allograft and patient survival than deceased-donor liver transplantation (DDLT). The risks to living donors and the benefit to their recipients have been carefully defined with long-term level 1 and 2 evidence-based study. An overview of the development and practice of living donor liver transplant (LDLT), including donor and recipient surgical allograft innovation, is provided. The issues of recipient selection, outcomes and morbidity, including disease-variable study and challenges past and present are presented in comparison with DDLT cohorts, and future insights are described. Central to practice is the careful and concise review of donor evaluation and selection and donor outcome, morbidity, quality of life and present and future strategies for donor advocacy and growth of the technique.

Evaluation of donor workups and exclusions in a single-center experience of living donor liver transplantation

The process of evaluating potential donors in liver transplantation is important to ensure donor safety and provide optimal recipient outcomes. However, there has been no report about donor exclusion rates and reasons for such exclusion in Korea. In this study, we aimed to elucidate the outcomes of potential living liver donor evaluation in a major living donor liver transplantation center. From July 2011 to June 2015, prospectively collected data of 726 potential donors for 588 matched recipients were subsequently evaluated. Among 726 potential donors, 374 potential donors (51.5%) finally reached donation; 352 potential donors (48.5%) were excluded for various reasons. Donor reasons were 29.8%, including medical problems, withdrawal of consent, graft volume issues, and identification of a better suitable donor. Recipient reasons were 20.7%, including recipient death or recovery, allocation to deceased donor, and progressions of hepatocellular carcinoma. A total of 38 (5.2%) potential donors had a fatty liver. Among them, 15 (39.5%) potential donors tried short-term weight reduction and eventually were able to donate. In conclusion, the main reasons for donor exclusion were medical problems and withdrawal of consent. Therefore, thorough medical screening and careful examination for donor voluntarism are important in the donor evaluation process. Liver Transplantation 23 614-624 2017 AASLD.

Robust sound speed estimation for ultrasound-based hepatic steatosis assessment

Hepatic steatosis is a common condition, the prevalence of which is increasing along with non-alcoholic fatty liver disease (NAFLD). Currently, the most accurate noninvasive imaging method for diagnosing and quantifying hepatic steatosis is MRI, which estimates the proton-density fat fraction (PDFF) as a measure of fractional fat content. However, MRI suffers several limitations including cost, contra-indications and poor availability. Although conventional ultrasound is widely used by radiologists for hepatic steatosis assessment, it remains qualitative and operator dependent. Interestingly, the speed of sound within soft tissues is known to vary slightly from muscle (1.575 mm · µs^-1) to fat (1.450 mm · µs^-1). Building upon this fact, steatosis could affect liver sound speed when the fat content increases. The main objectives of this study are to propose a robust method for sound speed estimation (SSE) locally in the liver and to assess its accuracy for steatosis detection and staging. This technique was first validated on two phantoms and SSE was assessed with a precision of 0.006 and 0.003 mm · µs^-1 respectively for the two phantoms. Then a preliminary clinical trial (N  =  17 patients) was performed. SSE results was found to be highly correlated with MRI proton density fat fraction (R ²  =  0.69) and biopsy (AUROC  =  0.952) results. This new method based on the assessment of spatio-temporal properties of the local speckle noise for SSE provides an efficient way to diagnose and stage hepatic steatosis.

Impact of Graft Type in Living Donor Liver Transplantation: Remnant Liver Regeneration and Outcome in Donors

OBJECTIVES

Liver regeneration and donor safety in right-lobe (RL) and left-lobe (LL) grafts are essential for donors in living donor liver transplantation (LDLT). Our aim was to compare the liver regeneration rate and postoperative outcome between different donor graft types in LDLT.

MATERIALS AND METHODS

A total of 95 donors were divided into 2 groups: RL (n = 42) and LL (n = 53). The remnant liver of LL donors were subdivided into 3 subgroups according to the different hepatic venous drainage pattern that dominates from right hepatic vein (dominant RHV; n = 34), middle hepatic vein (dominant MHV; n = 10), and include MHV for left lateral segment (LLS) graft (n = 9). The demographic data, postoperative laboratory data, complications, remnant liver volume (RLV), and remnant liver regeneration rate (RLRR) 6 months after surgery were compared.

RESULTS

The postoperative total bilirubin (TB), prothrombin time (PT), and intensive care unit (ICU) stays of the LL group were lower than the RL group (P < .05). The LL group has no significant better regeneration rate 6 months after surgery than the RL group. However, dominant RHV and LLS groups have significantly better RLRR than the RL group (89.2% vs 86% and 95.1% vs 86%, respectively, P < .05), but no significance in the dominant MHV group.

CONCLUSION

In conclusion, different hepatic venous drainage patterns of remnant liver grafts may affect the regeneration rate in LL LDLT, especially with dominant RHV donors, may have more comparable outcomes with that of RL, and should be a favorable option during donor selection.

Evaluation of Potential Donors in Living Donor Liver Transplantation

INTRODUCTION

Correct donor selection in living donor liver transplantation (LDLT) is essential not only to decrease the risks of complications for the donors but also to increase the survival of both the graft and the recipient. Knowing their most frequent reasons of donor elimination is so important for transplantation centers to gain time. In this study we evaluated the effectiveness of potential donors in LDLT and studied the reasons for nonmaturation of potential liver donors at our transplantation center.

PATIENTS AND METHODS

We studied the outcomes of 342 potential living donor candidates for 161 recipient candidates for liver transplantation between January 2013 and June 2014. Donor candidates' gender, age, body mass index (BMI), relationship with recipient, and causes of exclusion were recorded.

RESULTS

Among 161 recipients, 96 had a LDLT and 7 had cadaveric liver transplantation. Twelve of the 342 potential donors did not complete their evaluation; 106 of the remaining 330 donor candidates were accepted as suitable for donation (32%) but 10 of these were excluded preoperatively. The main reasons for unsuitability for liver donation were small remnant liver size (43%) and fatty changes of the liver (38.4%). Other reasons were arterial anatomic variations, ABO incompatibility, and Gilbert syndrome. Only 96 of the candidates (29% of the 330 candidates who completed the evaluation) underwent donation. Effective donors were 29% of potential and 90.5% of suitable donors.

CONCLUSIONS

In our center, 106 of 330 (32%) donor candidates were suitable for donation and the main reasons for unsuitability for liver donation were small remnant liver size and fatty changes of the liver.

Declining liver graft quality threatens the future of liver transplantation in the United States

National liver transplantation (LT) volume has declined since 2006, in part because of worsening donor organ quality. Trends that degrade organ quality are expected to continue over the next 2 decades. We used the United Network for Organ Sharing (UNOS) database to inform a 20-year discrete event simulation estimating LT volume from 2010 to 2030. Data to inform the model were obtained from deceased organ donors between 2000 and 2009. If donor liver utilization practices remain constant, utilization will fall from 78% to 44% by 2030, resulting in 2230 fewer LTs. If transplant centers increase their risk tolerance for marginal grafts, utilization would decrease to 48%. The institution of "opt-out" organ donation policies to increase the donor pool would still result in 1380 to 1866 fewer transplants. Ex vivo perfusion techniques that increase the use of marginal donor livers may stabilize LT volume. Otherwise, the number of LTs in the United States will decrease substantially over the next 15 years. In conclusion, the transplant community will need to accept inferior grafts and potentially worse posttransplant outcomes and/or develop new strategies for increasing organ donation and utilization in order to maintain the number of LTs at the current level.

Liver Transplantation Update: 2014

The first liver transplantation (LT) was performed by Thomas E Starzl five decades ago, and yet it remains the only therapeutic option offering gold standard treatment for end-stage liver disease (ESLD) and acute liver failure (ALF) and certain early-stage liver tumors. Post-liver transplantation survival has also dramatically improved over the last few decades despite increasing donor and recipient age and more frequent use of marginal organs to overcome the organ shortage. Currently, the overall 1 year survival following LT in the United States is reported as 85 to 90%, while the 10 years survival rate is ~50% (http://www.unos.org). The improvements are mainly due to progress in surgical techniques, postoperative intensive care, and the advent of new immunosuppressive agents. There are a number of factors that influence the outcomes prior to transplantation. Since 2002, the model for end-stage liver disease (MELD) score has been considered a predicting variable. It has been used to prioritize patients on the transplant waiting list and is currently the standard method used to assess severity in all etiologies of cirrhosis. Hepatocellular carcinoma (HCC) is the most common standard MELD exception because the MELD does not necessarily reflect the medical urgency of patients with HCC. The criteria for candidates with HCC for receiving LT have evolved over the past decade. Now, patients with HCC who do not meet the traditional Milan (MC) or UCSF criteria for LT often undergo downstaging therapy I an effort to shrink the tumor size. The shortage of donor organs is a universal problem. In some countries, the development of a deceased organ donation program has been prevented due to socioeconomic, cultural, legal and other factors. Due to the shortage of cadaveric donors, several innovative techniques have been developed to expand the organ donor pool, such as split liver grafts, marginal- or extended-criteria donors, live donor liver transplantation (LDLT), and the use of organs donated after cardiac death. Herein, we briefly summarize recent advances in knowledge related to LT. We also report common causes of death after liver transplant, including the recurrence of hepatitis C virus (HCV) and its management, and coronary artery disease (CAD), including the role of the cardiac calcium score in identifying occult CAD.

HOW TO CITE THIS ARTICLE

Dogan S, Gurakar A. Liver Transplantation Update: 2014. Euroasian J Hepato-Gastroenterol 2015;5(2):98-106.

Getting Used to Being a Patient: The Postoperative Experience of Living Liver Transplant Donors

Context—

Living donor liver transplant is a viable option for eligible persons in need of a liver transplant, but little is known about the hospitalization experience of patients undergoing hepatectomy for transplant donation.

Objective—

To explore the hospital experience of patients recovering from donor hepatectomy.

Design—

A qualitative interpretive descriptive design was used to understand the hospital experience of patients recovering from donor hepatectomy. Semistructured interviews, conducted before discharge, were audiotaped and transcribed verbatim. Coding was performed independently, then jointly by investigators to reach consensus on emerging themes.

Setting—

Major university hospital in the Northeastern United States.

Sample—

Adults (>18 years of age) whose primary language was English or Spanish and who could provide written informed consent.

Results—

The sample consisted of 15 participants who had a mean age of 34.6 years; half were women. Most were white and college educated. The relationship of the donors to recipients varied from immediate family to altruistic donors. “Getting used to being a patient” was the major theme that captured the patients' postoperative experience. Four subthemes explained the experience: regaining consciousness, all those tubes, expecting horrible pain, and feeling special and cared for. These were described in the context of an “amazing and impressive” transplant team.

Conclusion—

As healthy donors are getting used to being patients, these results provide clinicians with a deeper understanding of the transplant experience from the donor's perspective so that care can be tailored to meet their unique needs.

Combined Use of MR Fat Quantification and MR Elastography in Living Liver Donors: Can It Reduce the Need for Preoperative Liver Biopsy?

PURPOSE

To evaluate the diagnostic performance of magnetic resonance (MR) fat quantification and MR elastography for the assessment of hepatic steatosis and fibrosis in living liver donor candidates.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, and the requirement of informed consent was waived. Donors who underwent MR fat quantification and MR elastography at 1.5 T, followed by liver biopsy, were chronologically grouped into test and validation groups. In the test group (n = 362), MR fat fraction and liver stiffness were compared among donors with normal parenchyma (n = 244), simple steatosis (n = 71), steatosis with inflammatory activity (n = 21), nonalcoholic steatohepatitis (n = 17), and fibrosis (n = 9). Diagnostic performance of the two techniques was assessed by using receiver operating characteristic curve analysis for the detection of substantial steatosis (macrovesicular fat ≥ 10%) or fibrosis (≥F1) and was tested in a validation group (n = 34).

RESULTS

In the test group, donors with steatosis showed significantly higher fat fraction than donors without steatosis (P < .0001), and donors with fibrosis and nonalcoholic steatohepatitis showed significantly higher liver stiffness values than donors without fibrosis (P < .0001). Areas under the curve were 0.93 (cutoff value > 5.8%) for MR fat quantification and 0.85 (cutoff value > 1.94 kPa) for MR elastography. By using those values, the combination of the two techniques could be used to detect substantial steatosis or fibrosis with 100% sensitivity (12 of 12 patients, 95% confidence interval: 73.4%, 100%) and 100% negative predictive value (15 of 15 patients, 95% confidence interval: 78.0%, 100%) in the validation group.

CONCLUSION

A combination of MR fat quantification and MR elastography can provide sufficient sensitivity to detect substantial steatosis or fibrosis (≥F1) in liver donor candidates.

Hepatic steatosis in living liver donor candidates: preoperative assessment by using breath-hold triple-echo MR imaging and 1H MR spectroscopy

PURPOSE

To evaluate the diagnostic performance of both breath-hold T2*-corrected triple-echo spoiled gradient-echo water-fat separation magnetic resonance (MR) imaging (triple-echo imaging) and high-speed T2-corrected multiecho hydrogen 1 ((1)H) MR spectroscopy in the assessment of macrovesicular hepatic steatosis in living liver donor candidates by using histologic assessment as a reference standard.

MATERIALS AND METHODS

The institutional review board approved this retrospective study with waiver of the need to obtain informed consent. One hundred eighty-two liver donor candidates who had undergone preoperative triple-echo imaging and single-voxel (3 × 3 × 3 cm) MR spectroscopy performed with a 3.0-T imaging unit and who had also undergone histologic evaluation of macrovesicular steatosis were included in this study. In part 1 of the study (n = 84), the Pearson correlation coefficient was calculated. Receiver operating characteristic (ROC) curve analysis was performed to detect substantial (≥10%) macrovesicular steatosis. In part 2 of the study, with a different patient group (n = 98), diagnostic performance was evaluated by using the diagnostic cutoff values determined in part 1 of the study.

RESULTS

The correlation coefficients of triple-echo MR imaging and MR spectroscopy with macrovesicular steatosis were 0.886 and 0.887, respectively. The areas under the ROC curve for detection of substantial macrovesicular steatosis were 0.959 and 0.988, with cutoff values of 4.93% and 5.79%, respectively, and without a significant difference (P = .328). In the part 2 study group, sensitivity and specificity were 90.9% (10 of 11) and 86.2% (75 of 87) for triple-echo MR imaging and 90.9% (10 of 11) and 86.2% (75 of 87) for MR spectroscopy, respectively.

CONCLUSION

Either breath-hold triple-echo MR imaging or MR spectroscopy can be used to detect substantial macrovesicular steatosis in living liver donor candidates. In the future, this may allow selective biopsy in candidates who are expected to have substantial macrovesicular steatosis on the basis of MR-based hepatic fat fraction.

Identification of novel clinical factors associated with hepatic fat accumulation in extreme obesity

OBJECTIVES

The accumulation of lipids stored as excess triglycerides in the liver (steatosis) is highly prevalent in obesity and has been associated with several clinical characteristics, but most studies have been based on relatively small sample sizes using a limited set of variables. We sought to identify clinical factors associated with liver fat accumulation in a large cohort of patients with extreme obesity.

METHODS

We analyzed 2929 patients undergoing intraoperative liver biopsy during a primary bariatric surgery. Univariate and multivariate regression modeling was used to identify associations with over 200 clinical variables with the presence of any fat in the liver and with moderate to severe versus mild fat accumulation.

RESULTS

A total of 19 data elements were associated with the presence of liver fat and 11 with severity of liver fat including ALT and AST, plasma lipid, glucose, and iron metabolism variables, several medications and laboratory measures, and sleep apnea. The accuracy of a multiple logistic regression model for presence of liver fat was 81% and for severity of liver fat accumulation was 77%.

CONCLUSIONS

A limited set of clinical factors can be used to model hepatic fat accumulation with moderate accuracy and may provide potential mechanistic insights in the setting of extreme obesity.