Right lobe living donor liver transplantation-addressing the middle hepatic vein controversy

Estimation of right lobe graft weight for living donor liver transplantation using deep learning-based fully automatic computed tomographic volumetry

This study aimed at developing a fully automatic technique for right lobe graft weight estimation using deep learning algorithms. The proposed method consists of segmentation of the full liver region from computed tomography (CT) images, classification of the entire liver region into the right and left lobes, and estimation of the right lobe graft weight from the CT-measured right lobe graft volume using a volume-to-weight conversion formula. The first two steps were performed with a transformer-based deep learning model. To train and evaluate the model, a total of 248 CT datasets (188 for training, 40 for validation, and 20 for testing and clinical evaluation) were used. The Dice similarity coefficient (DSC), mean surface distance (MSD), and the 95th percentile Hausdorff distance (HD95) were used for evaluating the segmentation accuracy of the full liver region and the right liver lobe. The correlation coefficient (CC), percentage error (PE), and percentage absolute error (PAE) were used for the clinical evaluation of the estimated right lobe graft weight. The proposed method achieved high accuracy in segmentation for DSC, MSD, and HD95 (95.9% ± 1.0%, 1.2 ± 0.4 mm, and 5.2 ± 1.9 mm for the entire liver region; 92.4% ± 2.7%, 2.0 ± 0.7 mm, and 8.8 ± 2.9 mm for the right lobe) and in clinical evaluation for CC, PE, and PAE (0.859, - 1.8% ± 9.6%, and 8.6% ± 4.7%). For the right lobe graft weight estimation, the present study underestimated the graft weight by - 1.8% on average. A mean difference of - 21.3 g (95% confidence interval: - 55.7 to 13.1, p = 0.211) between the estimated graft weight and the actual graft weight was achieved in this study. The proposed method is effective for clinical application.

AFP Response to Locoregional Therapy Can Stratify the Risk of Tumor Recurrence in HCC Patients after Living Donor Liver Transplantation

(1) Background: Alpha-fetoprotein (AFP) has been incorporated into the selection criteria of liver transplantation and been used to predict the outcome of hepatocellular carcinoma (HCC) recurrence. Locoregional therapy (LRT) is recommended for bridging or downstaging in HCC patients listed for liver transplantation. The aim of this study was to evaluate the effect of the AFP response to LRT on the outcomes of hepatocellular carcinoma patients after living donor liver transplantation (LDLT). (2) Methods: This retrospective study included 370 HCC LDLT recipients with pretransplant LRT from 2000 to 2016. The patients were divided into four groups according to AFP response to LRT. (3) Results: The nonresponse group had the worst 5-year cumulative recurrence rates whereas the complete-response group (patients with abnormal AFP before LRT and with normal AFP after LRT) had the best 5-year cumulative recurrence rate among the four groups. The 5-year cumulative recurrence rate of the partial-response group (AFP response was over 15% lower) was comparable to the control group. (4) Conclusions: AFP response to LRT can be used to stratify the risk of HCC recurrence after LDLT. If a partial AFP response of over 15% declineis achieved, a comparable result to the control can be expected.

Selection of Safe Donors for Living Donor Liver Transplant Using Extended Right Lobe Graft

Extended right lobectomy (ERL) for living donor liver transplant (LDLT) is selectively performed in many transplant centers and has shown excellent recipient outcomes as reported in previous studies. Yet, there is no universally accepted indication for ERL in respect to donor safety. Current study was designed to stratify risk factors of adverse donor outcome after ERL. A total of 79 living donors who underwent ERL for LDLT were included in analysis. Donors were classified as safety and hazard donor groups according to postoperative findings relevant to posthepatectomy liver failure classification by the International Study Group for Liver Surgery. On multivariable analysis, left lateral section volume <20% of total liver volume and nonpreservation of segment 4a venous drainage were the independent risk factors impairing postoperative outcomes. Despite the short-term impairment of liver function in hazard donor groups, all donors recovered and showed satisfactory remnant liver regeneration. However, these findings have implications in establishing selection criteria of donors eligible for ERL donation. In conclusion, LDLT using ERL graft can be safely performed provided so that left lateral section volume/total donor liver is ≥20% besides conventional donor selection criteria. Also, efforts to preserve segment 4a vein must be made in performing ERL graft procurement in LDLT donors.

Importance of reconstruction of middle hepatic vein tributaries of right-lobe grafts in living donor liver transplantation: demonstration of the reconstruction technique

PURPOSE

The aim of the present study on living donor liver transplantation (LDLT) using a right-lobe graft without the middle hepatic vein (MHV) was to investigate the clinical impact of MHV tributary reconstruction using our criteria and techniques.

METHODS

The medical records of 40 patients who underwent adult LDLT using a right-lobe graft without the MHV between April 2008 and December 2020 were retrospectively reviewed. In this cohort, the criterion for MHV tributary reconstruction was estimated drainage volume of each MHV tributary greater than 100 mL. The drainage vein of segment 8 (V8) was reconstructed as the common orifice of the right hepatic vein and V8 using a venous patch graft, and that of segment 5 was reconstructed using artificial vascular grafts. The outcomes were compared between the groups with and without MHV tributary reconstruction. Factors associated with postoperative massive ascites were also investigated.

RESULTS

Twenty patients underwent MHV tributary reconstruction. There were no significant differences in the amount of postoperative ascites, Clavien-Dindo classification ≥ III postoperative complications, and 90-day in-hospital mortality between the groups (P = 0.678, P = 1.000, and P = 0.244, respectively). On multivariate analyses, a low-estimated functional graft-to-recipient weight ratio, which was calculated using estimated graft volume minus the territory of MHV tributaries that was not reconstructed, was identified as an independent predictor of postoperative massive ascites (odds ratio, 40.479; 95% confidence interval, 3.823-428.622).

CONCLUSION

The present study suggests that selective MHV tributary reconstruction might be useful for achieving successful graft function.

A review of split liver transplantation with full right/left hemi-liver grafts for 2 adult recipients

Liver transplantation has become a routine operation in many transplantation centers worldwide. However, liver graft availability fails to meet patient demands. Split liver transplantation (SPLT), which divides a deceased donor liver into 2 partial liver grafts, is a promising strategy for increasing graft availability for transplantation and ameliorating organ shortage to a certain degree. However, the transplantation community has not yet reached a consensus on SPLT because of the variable results. Specifically, SPLT for 2 adult recipients using full right/left hemi-liver grafts is clinically more challenging in terms of surgical technique and potential postoperative complications. Therefore, this review summarizes the current status of SPLT, focusing on the transplantation of adult recipients. Furthermore, the initiation of the SPLT program, donor allocation, surgical aspects, recipient outcomes, and obstacles to developing this procedure will be thoroughly discussed. This information might help provide an optimal strategy for implementing SPLT for 2 adult recipients among current transplantation societies. Meanwhile, potential obstacles to SPLT might be overcome in the near future with growing knowledge, experience, and refinement of surgical techniques. Ultimately, the widespread diffusion of SPLT may increase graft availability and mitigate organ donation shortages.

Imaging Evaluation of Living Liver Donor Candidates: Techniques, Protocols, and Anatomy

The need for liver transplants is increasing because the prevalence of liver diseases and the indications for transplants are growing. In response to the shortage of grafts from deceased donors, more transplants are being performed worldwide with grafts from living donors. Radiologic evaluation is an integral component in the assessment of donor candidates to ensure their eligibility and to choose the most appropriate surgical approach. MRI is the preferred modality for evaluation of the liver parenchyma and biliary tree. In most centers, a combination of MRI and CT is used to take advantage of the higher spatial resolution of CT for evaluation of arteries. However, MRI-only assessment is feasible. In addition to assessment of the liver parenchyma for abnormalities such as steatosis, a detailed evaluation of the hepatic vascular and biliary system for pertinent anatomic variants is crucial, because these variants can affect surgical techniques and outcomes in both recipients and donors. In this pictorial article, after a brief review of the most common surgical techniques and postsurgical liver anatomy, the biliary and vascular anatomy are discussed, with specific attention paid to the variants that are pertinent to this surgical procedure. The roles of liver segmentation and volumetric assessment and current imaging techniques and protocols are also discussed. Online supplemental material is available for this article. ©RSNA, 2021.

Intraoperative Increase of Portal Venous Pressure is an Immediate Predictor of Posthepatectomy Liver Failure After Major Hepatectomy: A Prospective Study

OBJECTIVES

The aim of this study was to assess intraoperative changes of hepatic macrohemodynamics and their association with ascites and posthepatectomy liver failure (PHLF) after major hepatectomy.

SUMMARY OF BACKGROUND DATA

Large-scale ascites and PHLF remain clinical challenges after major hepatectomy. No study has concomitantly evaluated arterial and venous liver macrohemodynamics in patients undergoing liver resection.

METHODS

Portal venous pressure (PVP), portal venous flow (PVF), and hepatic arterial flow (HAF) were measured intraoperatively pre- and postresection in 67 consecutive patients with major hepatectomy (ie, resection of ≥3 liver segments). A group of 30 patients with minor hepatectomy served as controls. Liver macrohemodynamics and their intraoperative changes (ie, Δ) were analyzed as predictive biomarkers of ascites and PHLF using Fisher exact, t test, or Wilcoxon rank sum test for univariate and logistic regression for multivariate analyses.

RESULTS

Major hepatectomy increased PVP by 26.9% (P = 0.001), markedly decreased HAF by 40.7% (P < 0.001), and slightly decreased PVF by 13.4% (P = 0.011). Minor resections had little effects on hepatic macrohemodynamics. There was no significant association of liver macrohemodynamics with ascites. While middle hepatic vein resection caused higher postresection PVP after right hepatectomy (P = 0.04), the Pringle maneuver was associated with a significant PVF (P = 0.03) and HAF reduction (P = 0.03). Uni- and multivariate analysis revealed an intraoperative PVP increase as an independent predictor of PHLF (P = 0.025).

CONCLUSION

Intraoperative PVP kinetics serve as independent predictive biomarker of PHLF after major hepatectomy. These data highlight the importance to assess intraoperative dynamics rather than the pre- and postresection PVP values.

Post-operative imaging anatomy in liver transplantation

The article describes and illustrates the surgical techniques and the post-operative imaging anatomy in liver transplantation. Special attention is paid to the variant vascular and biliary anatomy that are important for surgical planning. Considering the ever-growing number of liver transplants performed and the key role that imaging plays in the pre-operative planning and post-operative assessment, it is important for the radiologist to be familiar with the surgical techniques and the normal post-operative appearance in these patients.

The influence of the middle hepatic vein and its impact on outcomes in right lobe living donor liver transplantation

BACKGROUND

In adult right lobe living donor liver transplantation, the decision to include the middle hepatic vein (MHV) remains controversial.

METHODS

A retrospective analysis of 50 R-LDLTs between January 2008 and June 2016 was performed.

RESULTS

Twenty-one procedures were performed using a MHV+ graft (42.0%) and 29 procedures using a MHV- graft (58%). MHV- donors were taller (173 vs 166 cm, p = 0.004) with a larger standard liver volume (1351 vs 1245 mls, p = 0.014) compared to MHV+ donors. The duration of operation for donors was significantly longer in the MHV+ group (530 (313-975) mins) compared to the MHV- group (489 (336-708) mins) (p = 0.029). Similarly, the operative time for recipients was longer in the MHV+ group (660 (428-831) mins) compared to MHV- (579 (359-1214) mins) (p = 0.023). MHV- grafts were heavier compared to MHV+ grafts (918 vs 711 g, p = 0.017). Recipient mortality rates and Kaplan-Meier survival analysis were comparable (p = 0.411). All donors were well at last review.

CONCLUSION

Both MHV+ and MHV- grafts are safe for the donor and recipient. The decision to take the MHV should be based on specific donor-recipient characteristics.

Readdressing the Middle Hepatic Vein in Right Lobe Liver Donation: Triangle of Safety

For equipoising donor safety and optimal recipient outcomes, we adopted an algorithmic "triangle of safety" approach to retrieve 3 types of right lobe liver grafts (RLGs), namely, the modified extended right lobe graft (MERLG), the partial right lobe graft (PRLG), and the modified right lobe graft (MRLG). Reconstruction to achieve a single wide anterior sector outflow was ensured in all patients. We present donor and recipient outcomes based on our approach in 665 right lobe (RL) living donor liver transplantations (LDLTs) performed from January 2013 to August 2015. There were 347 patients who received a MERLG, 117 who received a PRLG, and 201 who received a MRLG. A right lobe graft (RLG) with a middle hepatic vein was retrieved only in 3 out of 18 donors with steatosis >10%. Cold ischemia time was significantly more and remnant volume was less in the MRLG group. Of the donors, 29.3% had complications (26% Clavien-Dindo grade I, II) with no statistically significant difference among the groups. The Model for End-Stage Liver Disease score was higher in the MERLG group. There were 34 out of 39 with a graft-to-recipient weight ratio (GRWR) of <0.7% who received a MERLG with inflow modulation. Out of 4 patients who developed small-for-size syndrome in this group, 2 died. The 90-day patient survival rate was similar among different GRWRs and types of RLG. In conclusion, a selective and tailored approach for RL donor hepatectomy based on optimal functional volume and metabolic demands not only addresses the key issue of double equipoise in LDLT but also creates a safe path for extending the limits.

Dr. Liver: A preoperative planning system of liver graft volumetry for living donor liver transplantation

BACKGROUND AND OBJECTIVE

Manual tracing of the right and left liver lobes from computed tomography (CT) images for graft volumetry in preoperative surgery planning of living donor liver transplantation (LDLT) is common at most medical centers. This study aims to develop an automatic system with advanced image processing algorithms and user-friendly interfaces for liver graft volumetry and evaluate its accuracy and efficiency in comparison with a manual tracing method.

METHODS

The proposed system provides a sequential procedure consisting of (1) liver segmentation, (2) blood vessel segmentation, and (3) virtual liver resection for liver graft volumetry. Automatic segmentation algorithms using histogram analysis, hybrid level-set methods, and a customized region growing method were developed. User-friendly interfaces such as sequential and hierarchical user menus, context-sensitive on-screen hotkey menus, and real-time sound and visual feedback were implemented. Blood vessels were excluded from the liver for accurate liver graft volumetry. A large sphere-based interactive method was developed for dividing the liver into left and right lobes with a customized cutting plane. The proposed system was evaluated using 50 CT datasets in terms of graft weight estimation accuracy and task completion time through comparison to the manual tracing method. The accuracy of liver graft weight estimation was assessed by absolute difference (AD) and percentage of AD (%AD) between preoperatively estimated graft weight and intraoperatively measured graft weight. Intra- and inter-observer agreements of liver graft weight estimation were assessed by intraclass correlation coefficients (ICCs) using ten cases randomly selected.

RESULTS

The proposed system showed significantly higher accuracy and efficiency in liver graft weight estimation (AD = 21.0 ± 18.4 g; %AD = 3.1% ± 2.8%; percentage of %AD > 10% = none; task completion time = 7.3 ± 1.4 min) than the manual tracing method (AD = 70.5 ± 52.1 g; %AD = 10.2% ± 7.5%; percentage of %AD > 10% = 46%; task completion time = 37.9 ± 7.0 min). The proposed system showed slightly higher intra- and inter-observer agreements (ICC = 0.996 to 0.998) than the manual tracing method (ICC = 0.979 to 0.999).

CONCLUSIONS

The proposed system was proved accurate and efficient in liver graft volumetry for preoperative planning of LDLT.

Kinetics of liver regeneration in donors after living donor liver transplantation: A retrospective analysis of "2/3rd partial hepatectomy" model at 3 months

BACKGROUND/AIM

Right lobe living donor (2/3rd partial hepatectomy) model is the best way to accurately study liver regeneration process in human beings. We aimed to study the kinetics of liver regeneration after 2/3rd partial hepatectomy in donors.

METHODS

Retrospective analysis of prospectively maintained volumetric recovery data in donors was performed in 23 donors, who underwent 29 contrast-enhanced computed tomography within 3 months for various clinical indications.

RESULTS

The absolute volumetric growth percentages were as follows: 37.60 ± 21.74 at 1st week, 92 ± 53.27 at 2nd week, 115.55 ± 59.65 at 4th week, and 110.79 ± 64.47 at 3 months. On sub-group analysis of our cohort, we found that 4.3%, 17%, 30.4%, and 39% donors attended ≥ 90% volumetric recovery at 1st, 2nd, 4th week, and 3 months, respectively. One patient at 4th week revealed 128% volumetric recovery. There was one more patient who exceeded original total liver volumes (TLV) (111% of TLV) at 2.5 months. The serum bilirubin and INR values peaked at postoperative day (POD) 3rd and then started showing a downward trend from POD 5th onwards.

CONCLUSION

Our study is the first to document complete volumetric recovery in donors as early as 3 weeks. Two of the donors overshot their original TLV during the early regenerative phase.

The International Liver Transplantation Society Living Donor Liver Transplant Recipient Guideline

Living donor liver transplantation (LDLT) has been increasingly embraced around the world as an important strategy to address the shortage of deceased donor livers. The aim of this guideline, approved by the International Liver Transplantation Society (ILTS), is to provide a collection of expert opinions, consensus, and best practices surrounding LDLT. Recommendations were developed from an analysis of the National Library of Medicine living donor transplantation indexed literature using the Grading of Recommendations Assessment, Development and Evaluation methodology. Writing was guided by the ILTS Policy on the Development and Use of Practice Guidelines (www.ilts.org). Intended for use by physicians, these recommendations support specific approaches to the diagnostic, therapeutic, and preventive aspects of care of living donor liver transplant recipients.

Compared to cadaveric liver transplantation, live donor LT (LDLT) is challenged by ethical, medical and surgical considerations, many of which are still unresolved. The aim of this guideline is to provide a collection of expert opinions, consensus, and best practices surrounding LDLT.

Adult-to-adult living donor liver transplantation: Operative techniques to optimize the recipient's outcome

Adult-to-adult living donor liver transplantation (LDLT) is widely accepted today with good outcomes and safety reported worldwide for both donor and recipient. Nonetheless, it remained a highly demanding technical and complex surgery if undertaken. The last two decades have seen an increased in adult-to-adult LDLT following our first report of right lobe LDLT in overcoming graft size limitation in adults. In this article, we discussed the operative techniques and challenges of adult right lobe LDLT incorporating the middle hepatic vein, which is practiced in our center for the recipient operation. The various issues and challenges faced by the transplant surgeon in ensuring good recipient outcome are explored and discussed here as well. Hence, it is important to understand that a successful recipient operation is dependent of multifactorial events starting at the preoperative stage of planning, understanding the intraoperative technical challenges and the physiology of flow modulation that goes hand-in-hand with the operation. Therefore, one needs to arm oneself with all the possible knowledge in overcoming these technical challenges and the ability to be flexible and adaptable during LDLT by tailoring the needs of each patient individually.

Prediction of postoperative liver regeneration from clinical information using a data-led mathematical model

Although the capacity of the liver to recover its size after resection has enabled extensive liver resection, post-hepatectomy liver failure remains one of the most lethal complications of liver resection. Therefore, it is clinically important to discover reliable predictive factors after resection. In this study, we established a novel mathematical framework which described post-hepatectomy liver regeneration in each patient by incorporating quantitative clinical data. Using the model fitting to the liver volumes in series of computed tomography of 123 patients, we estimated liver regeneration rates. From the estimation, we found patients were divided into two groups: i) patients restored the liver to its original size (Group 1, n = 99); and ii) patients experienced a significant reduction in size (Group 2, n = 24). From discriminant analysis in 103 patients with full clinical variables, the prognosis of patients in terms of liver recovery was successfully predicted in 85-90% of patients. We further validated the accuracy of our model prediction using a validation cohort (prediction = 84-87%, n = 39). Our interdisciplinary approach provides qualitative and quantitative insights into the dynamics of liver regeneration. A key strength is to provide better prediction in patients who had been judged as acceptable for resection by current pragmatic criteria.

The evolution of anterior sector venous drainage in right lobe living donor liver transplantation: does one technique fit all?

In living donor liver transplantation (LDLT), an adequate hepatic venous outflow constitutes one of the basic principles of a technically successful procedure. The issue of whether the anterior sector (AS) of the right lobe (RL) graft should or should not be routinely drained has been controversial. The aim of this 10-year, single-center, retrospective cohort study was to review the evolution of our hepatic venous outflow reconstruction technique in RL grafts and evaluate the impact of routine AS drainage strategy on the outcome. The study group consisted of 582 primary RL LDLT performed between July 2004 and December 2014. The cases were divided into 3 consecutive periods with different AS venous outflow reconstruction techniques, which included middle hepatic vein (MHV) drainage in Era 1 (n=119), a more selective AS drainage with cryopreserved homologous grafts in Era 2 (n=391), and routine segment 5 and/or 8 oriented AS drainage with synthetic grafts in Era 3 (n=72). Intraoperative portal flow measurement with routine splenic artery ligation (SAL) technique (in RL grafts with a portal flow of ≥ 250 mL/min/100 g liver tissue) was added later in Era 3. These 3 groups were compared in terms of recipient and donor demographics, surgical characteristics and short-term outcome. The rate of AS venous drainage varied from 58.8% in Era 1 and 35.0% in Era 2 to 73.6% in Era 3 (P<0.001). Perioperative mortality rate of recipients significantly decreased over the years (15.1% in Era 1 and 8.7% in Era 2 vs. 2.8% in Era 3, P=0.01). After the addition of SAL technique in the 45 cases, there was only 1 graft loss and no perioperative mortality. One-year recipient survival rate was also significantly higher in Era 3 (79.6% in Era 1 and 86.1% in Era 2 vs. 92.1% in Era 3, P=0.002). Routine AS drainage via segment 5 and/or 8 veins using synthetic grafts is a technique to fit all RL grafts in LDLT. Addition of SAL effectively prevents early graft dysfunction and significantly improves the outcome.

Ad Integrum Functional and Volumetric Recovery in Right Lobe Living Donors: Is It Really Complete 1 Year After Donor Hepatectomy?

The partial liver's ability to regenerate both as a graft and remnant justifies right lobe (RL) living donor liver transplantation. We studied (using biochemical and radiological parameters) the rate, extent of, and predictors of functional and volumetric recovery of the remnant left liver (RLL) during the first year in 91 consecutive RL donors. Recovery of normal liver function (prothrombin time [PT] ≥70% of normal and total bilirubin [TB] ≤20 µmol/L), liver volumetric recovery, and percentage RLL growth were analyzed. Normal liver function was regained by postoperative day's 7, 30, and 365 in 52%, 86%, and 96% donors, respectively. Similarly, mean liver volumetric recovery was 64%, 71%, and 85%; whereas the percentage liver growth was 85%, 105%, and 146%, respectively. Preoperative PT value (p = 0.01), RLL/total liver volume (TLV) ratio (p = 0.03), middle hepatic vein harvesting (p = 0.02), and postoperative peak TB (p < 0.01) were predictors of early functional recovery, whereas donor age (p = 0.03), RLL/TLV ratio (p = 0.004), and TLV/ body weight ratio (p = 0.02) predicted early volumetric recuperation. One-year post-RL donor hepatectomy, though functional recovery occurs in almost all (96%), donors had incomplete restoration (85%) of preoperative total liver volume. Modifiable predictors of regeneration could help in better and safer donor selection, while continuing to ensure successful recipient outcomes.

Management of the middle hepatic vein in right lobe living donor liver transplantation: A meta-analysis

Living donor liver transplantation (LDLT) is a curative treatment for end stage liver disease. It is advantageous due to the shortage of deceased donors. However, in LDLT, whether the middle hepatic vein (MHV) should be preserved in donors remains controversial. We conducted searches in Pubmed, Embase, Cochrane Library, Web of Science, Ovid, and Google Scholar using the key words "living donor liver transplantation" and "middle hepatic vein". Due to ethical issues, there were no randomized control trails focusing on MHV in LDLT. The majority of reports were retrospective studies. We examined the reference lists to identify related investigations. Google Scholar was then used to obtain full texts. Nine observational studies were analyzed. There were no significant differences in liver function (WMD, -5.51; P=0.12) and complications (RR, 0.98; P=0.89) in donors with or without MHV. However, the liver function in recipients was greatly improved after LDLT with MHV (WMD, -78.32; P=0.01). No definite conclusion was obtained in terms of the liver regeneration indices between LDLT with or without MHV. It was conclude that grafts with MHV in LDLT favor recipient outcomes and do not harm the living donor if a careful preoperative evaluation is performed.

Risk of venous congestion in live donors of extended right liver graft

AIM: To investigate middle hepatic vein (MHV) management in adult living donor liver transplantation and safer remnant volumes (RV).

METHODS: There were 59 grafts with and 12 grafts without MHV (including 4 with MHV-5/8 reconstructions). All donors underwent our five-step protocol evaluation containing a preoperative protocol liver biopsy Congestive vs non-congestive RV, remnant-volume-body-weight ratios (RVBWR) and postoperative outcomes were evaluated in 71 right graft living donors. Dominant vs non-dominant MHV anatomy in total liver volume (d-MHV/TLV vs nd-MHV/TLV) was constellated with large/small congestion volumes (CV-index). Small for size (SFS) and non-SFS remnant considerations were based on standard cut-off- RVBWR and RV/TLV. Non-congestive RVBWR was based on non-congestive RV.

RESULTS: MHV and non-MHV remnants showed no significant differences in RV, RV/TLV, RVBWR, total bilirubin, or INR. SFS-remnants with RV/TLV < 30% and non-SFS-remnants with RV/TLV ≥ 30% showed no significant differences either. RV and RVBWR for non-MHV (n = 59) and MHV-containing (n = 12) remnants were 550 ± 95 mL and 0.79 ± 0.1 mL vs 568 ± 97 mL and 0.79 ± 0.13, respectively (P = 0.423 and P = 0.919. Mean left RV/TLV was 35.8% ± 3.9%. Non-MHV (n = 59) and MHV-containing (n = 12) remnants (34.1% ± 3% vs 36% ± 4% respectively, P = 0.148. Eight SFS-remnants with RVBWR < 0.65 had a significantly smaller RV/TLV than 63 non-SFS-remnants with RVBWR ≥ 0.65 [SFS: RV/TLV 32.4% (range: 28%-35.7%) vs non-SFS: RV/TLV 36.2% (range: 26.1%-45.5%), P < 0.009. Six SFS-remnants with RV/TLV < 30% had significantly smaller RVBWR than 65 non-SFS-remnants with RV/TLV ≥ 30% (0.65 (range: 0.6-0.7) vs 0.8 (range: 0.6-1.27), P < 0.01. Two (2.8%) donors developed reversible liver failure. RVBWR and RV/TLV were concordant in 25%-33% of SFS and in 92%-94% of non-SFS remnants. MHV management options including complete MHV vs MHV-4A selective retention were necessary in n = 12 vs n = 2 remnants based on particularly risky congestive and non-congestive volume constellations.

CONCLUSION: MHV procurement should consider individual remnant congestive- and non-congestive volume components and anatomy characteristics, RVBWR-RV/TLV constellation enables the identification of marginally small remnants.

Surgical experience of adult primary hepatic sarcomas

BACKGROUND

Primary hepatic sarcoma (PHS) is a rare primary liver malignancy. The histological types of PHS are diverse, and the clinical outcomes and management mainly depend on the histopathology. This study aims to evaluate the results of surgical intervention.

METHODS

Between January 2003 and June 2009, 13 adult patients with pathologically proven PHS were identified by record review. The patients' demographic profile, tumor characteristics, treatment modalities, and outcomes were reviewed and analyzed. The end of follow-up was December 2014.

RESULTS

Nine (69%) underwent curative liver resection and two underwent liver transplantation; the others received non-operative treatments. The pathologic findings were six (46%) angiosarcomas, four (30.7%) undifferentiated sarcomas, one (7.6%) leiomyosarcoma, one (7.6%) malignant mesenchymoma, and one (7.6%) hepatic epithelioid hemangioendothelioma. The median follow-up was 31.4 (2.8 ~ 142.5) months. The 1-, 2-, and 5-year survival of surgical patients were 72.7%, 63.6%, and 36.4%, respectively. Importantly, the 1-, 2-, and 5-year survival rates of non-angiosarcoma patients were superior to those of angiosarcoma (85.7% vs. 33.3%, 71.4% vs. 16.7%, and 57.1% vs. 0%, respectively, P = 0.023).

CONCLUSIONS

Surgical intervention provides the possibility of long-term survival from PHS. Angiosarcoma is associated with a more dismal outcome than non-angiosarcoma.

Adult right living-donor liver transplantation with special reference to reconstruction of the middle hepatic vein

Two hundred fifty-three consecutive living-donor liver transplant recipients with a right liver graft (RLG) were divided into three groups: an extended right liver graft (ERLG) group (n = 47) in which the middle hepatic vein (MHV) trunk was included in the graft, a modified right liver graft (MRLG) group (n = 114) in which the MHV tributaries were reconstructed with cryopreserved homologous veins and a simple RLG group (n = 92) in which the MHV tributaries were sacrificed. The volume of the anterior sector was significantly impaired in the RLG group compared to the other two groups, whereas the volume of the posterior sector was significantly improved in the RLG group, indicating that the impaired anterior sector regeneration by MHV deprivation was compensated by the posterior sector regeneration. The regeneration rate of the anterior sector was highest in the ERLG group (92%), moderate in the MRLG group (71%) and lowest in the RLG group (52%). The whole graft regeneration rate of the ERLG group was significantly higher than that of the other two groups. Poor regeneration, however, was not correlated with delayed functional recovery or long-term outcome. Short-term, the patency of reconstructed MHV tributaries was over 90%, but occlusion occurred frequently over the long-term, especially in V5.

Outcomes of long storage times for cryopreserved vascular grafts in outflow reconstruction in living donor liver transplantation

The outflow reconstruction of the right anterior sector in a right liver graft (RLG) with cryopreserved vascular grafts (CVGs) is crucial for preventing graft congestion in living donor liver transplantation (LDLT). The impact of the duration of cryopreservation has not been evaluated so far. From 2006 to 2009, 250 LDLT were performed: 47 of these patients (group 1) received CVGs stored for ≦1 year, and 33 patients (group 2) received CVGs stored for >1 year. Single or multiple segment 8 hepatic veins were reconstructed. The number of anastomoses did not affect vascular graft patency (P = 0.21). The length of the cryopreservation time did not affect the histological findings for CVGs. The preoperative and postoperative liver graft volumes were 783.8 ± 129.7 and 1102 ± 194.7 cc, respectively, for group 1 and 753.7 ± 158.5 and 1097.2 ± 178.7 cc, respectively, for group 2. The regeneration indices for liver grafts in the whole patient group, group 1, and group 2 were 48.9%, 47.4%, and 51.05%, respectively. In conclusion, the storage duration has no impact on the patency of CVGs in outflow reconstruction or on the regeneration of RLGs in LDLT. CVGs stored for >1 year can be safely used for the outflow reconstruction of RLGs in LDLT.

Outcome of patients undergoing right lobe living donor liver transplantation with small-for-size grafts

AIM: To investigate the outcome of living donor liver transplantation (LDLT) recipients transplanted with small-for-size grafts (SFSGs).

METHODS: Between November 2001 and December 2010, 196 patients underwent LDLT with right lobe liver grafts at our center. Recipients were divided into 2 treatment groups: group A with an actuarial graft-to-recipient weight ratio (aGRWR) < 0.8% (n = 45) and group B with an aGRWR ≥ 0.8% (n = 151). We evaluated serum liver function markers within 4 wk after transplantation. We also retrospectively evaluated the outcomes of these patients for potential effects related to the recipients, the donors and the transplantation procedures based upon a review of their medical records.

RESULTS: Small-for-size syndrome (SFSS) developed in 7 of 45 patients (15.56%) in group A and 9 of 151 patients (5.96%) in group B (P = 0.080). The levels of alanine aminotransferase and aspartate aminotransferase in group A were higher than those in group B during early period after transplantation, albeit not significantly. The cumulative 1-, 3- and 5-year liver graft survival rates were 82.22%, 71.11% and 71.11% for group A and 81.46%, 76.82%, and 75.50% for group B patients, respectively (P = 0.623). However, univariate analysis of risk factors associated with graft survival in group A demonstrated that the occurrence of SFSS after LDLT was the only significant risk factor affecting graft survival (P < 0.001). Furthermore, multivariate analysis of our data did not identify any additional significant risk factors accounting for poor graft survival.

CONCLUSION: Our study suggests that LDLT recipients with an aGRWR < 0.8% may have liver graft outcomes comparable to those who received larger size grafts. Further studies are required to ascertain the safety of using SFSGs.

Venous Outflow Reconstruction in Adult Living Donor Liver Transplant: Outcome of a Policy for Right Lobe Grafts without the Middle Hepatic Vein

Introduction. The difficulty and challenge of recovering a right lobe graft without MHV drainage is reconstructing the outflow tract of the hepatic veins. With the inclusion or the reconstruction of the MHV, early graft function is satisfactory. The inclusion of the MHV or not in the donor's right lobectomy should be based on sound criteria to provide adequate functional liver mass for recipient, while keeping risk to donor to the minimum. Objective. Reviewing the results of a policy for right lobe grafts transplant without MHV and analyzing methods of venous reconstruction related to outcome. Materials and Methods. We have two groups Group A (with more than one HV anast.) (n = 16) and Group B (single HV anast.) (n = 24). Both groups were compared regarding indications for reconstruction, complications, and operative details and outcomes, besides describing different modalities used for venous reconstruction. Results. Significant increase in operative details time in Group A. When comparison came to complications and outcomes in terms of laboratory findings and overall hospital stay, there were no significant differences. Three-month and one-year survival were better in Group A. Conclusion. Adult LDLT is safely achieved with better outcome to recipients and donors by recovering the right lobe without MHV, provided that significant MHV tributaries (segments V, VIII more than 5 mm) are reconstructed, and any accessory considerable inferior right hepatic veins (IRHVs) or superficial RHVs are anastomosed.

Portal flow is the main predictor of early graft dysfunction regardless of the GRWR status in living donor liver transplantation - a retrospective analysis of 134 patients

BACKGROUND

Sometimes even in adequate graft to recipient weight ratio (GRWR) settings and after ruling out all other causes, recipients still show features of the small for size syndrome. The purpose of this study was to evaluate all causative factors responsible for early graft dysfunction fulfilling the definition of the small for size syndrome, regardless of the GRWR status, and with particular emphasis on portal flow (ml/min/100 g). We also tried to establish whether a high portal flow on intraoperative Doppler study immediately after reperfusion can predict graft dysfunction.

MATERIAL AND METHODS

Early graft dysfunction was defined according to the definitions given for the small for size syndrome by the Kyushu University Group. Patients undergone living donor liver transplantations between January 2010 and December 2012 were analyzed. We routinely do Doppler ultrasound (USG) immediately after reperfusion and daily for 5 days. The portal vein flow after routine Doppler examination immediately after reperfusion was noted as the portal vein flow at day 0.

RESULTS

19 of 134 patients showed features of early graft dysfunction as defined. On univariate analysis, hepatitis C virus (HCV) and portal vein flow immediately after reperfusion were significant predictors of postoperative graft dysfunction. (p = 0.008 and p < 0.0001). On multivariate logistic regression, only portal vein flow after reperfusion (p = 0.002) remained as the significant predictor of postoperative graft dysfunction. A portal flow of greater than 190 (ml/min/100 g) was significant in predicting graft dysfunction (p < 0.0001) with an AUROC of 0.709. GRWR was not a significant predictor.

CONCLUSION

A portal vein flow immediately after reperfusion >190/ml/min/100 g. reliably predicted whether a graft would behave as small for size or not, regardless of the GRWR status. Portal vein flow was the most significant predictor of graft dysfunction.

Impacts of pretransplant infections on clinical outcomes of patients with acute-on-chronic liver failure who received living-donor liver transplantation

Background

Liver transplantation is the only therapeutic modality for patients with acute-on chronic liver failure (ACLF). These patients are at high risk for bacterial infections while awaiting transplantation. The aim of this study was to elucidate whether an adequately treated bacterial infection influences the outcomes after transplantation in this patient population.

Methodology/Principal Findings

54 recipients (median age, 49.5 years [range, 22–60]) of adult-to-adult living donor liver transplant (LDLT) for ACLF were categorized as those with pretransplant infection (Group 1, n = 34) or without pretransplant infection (Group 2, n = 20) for retrospective analyses. With the exception of a higher male-female ratio (P = 0.046) and longer length of pretransplant hospital stay (P = 0.026) in Group 1, similar demographic, laboratory and clinical features were found in both groups. Patients in Group 1 (totally 42 pretransplant infection episodes) were adequately treated with effective antibiotic(s) before receiving LDLT. All included patients were followed up until one year after transplantation or death. Sixty-one posttransplant infection episodes were found in an overall of 44 ACLF patients (27 in Group 1 vs. 15 in Group 2; P = 0.352). Frequently encountered posttransplant infections were intraabdominal infection, pneumonia, bloodstream infection and urinary tract infection. Two patients died in each group (P = 0.622). No significant difference was found in the length of posttransplant ICU stay, and in one-year survival, graft rejection, and posttransplant infection rate between both groups. The longer overall hospital stay (mean day, 89.0 vs. 65.5, P = 0.024) found in Group 1 resulted from a longer pretransplant hospital stay receiving treatment for pretransplant infection(s) and/or awaiting transplantation.

Conclusions

These data suggested that an adequately treated pretransplant infection do not pose a significant risk for clinical outcomes including posttransplant fatality in recipients in adult-to-adult LDLT for ACLF.

Computer-assisted surgical planning in adult-to-adult live donor liver transplantation: how much does it help? A single center experience

BACKGROUND

Preoperative imaging and donor selection are cardinal components of adult-to-adult live donor liver transplantation (ALDLT). The purpose of this study was to evaluate our three-dimensional (3D) computed tomography image-derived computer-assisted surgical planning (3D CASP) in ALDLT.

METHODS

Eighty-three consecutive ALDLTs (71 right and 12 left) were planned with 3D CASP. Graft, remnant, and total liver volume compliance were calculated and compared with actual intraoperative values. Computed risk analysis encompassing territorial liver mapping, functional (safely drained) volumes, and outflow congestion volumes in grafts and remnants allowed for the individualized management of the middle hepatic vein (MHV).

RESULTS

Graft volume compliance was 13.5%±4.4%. Three small-for-size (SFS) grafts with lethal SFS syndrome (SFSS) had nonsignificant volume compliance with maximal graft volume-body weight ratios of less than 0.83. Seven SFS grafts with reversible or absent SFSS showed maximal graft volume-body weight ratios of 0.9 to 1.16. Significant differences were identified for (a) virtual graft and remnant congestion volumes of risky versus nonrisky MHV types (49%±6% and 34%±7% vs. 29%±8% and 33%±12%, P<0.001 and P<0.02, respectively) and (b) virtual mean functional versus surgical volumes of grafts (527±119 vs. 963±176 mL, P<0.0001) and remnants (419±182 vs. 640±213 mL, P<0.001).

CONCLUSIONS

CASP allowed for (a) prevention of SFSS in extremely small grafts by predicting donor liver plasticity and (b) individualized MHV management for both donors and recipients based on functional graft/remnant volume analysis.

Relationship between preoperative volume and weight of the right liver lobe graft, with and without the middle hepatic vein, in living-donor transplantation

BACKGROUND

The aim of this study was to assess the relationship between the preoperative volume of the right liver lobe (as determined by computed tomography) and the intraoperative graft weight with or without the middle hepatic vein.

METHODS

Sixty-three patients who underwent liver transplantation were included in this study. The preoperative volumes of both the left and the right liver lobe were measured in all patients using computed tomography. The intraoperative weight of the right liver lobe was also measured with (group 1, n = 29) and without (group 2, n = 34) the middle hepatic vein. The results were compared with respect to gender, age, body weight, height, body mass index (BMI), weights of the left and right liver lobes as measured by computed tomography, and intraoperative weight of the right liver lobe.

RESULTS

A 21.64 % difference was observed between the weight of the right liver lobe as measured by computed tomography and the weight of the right lobe without the hepatic vein as measured intraoperatively (group 2). Moreover, a 12.38 % difference was observed between the weight of the right liver lobe as measured by computed tomography and the weight of the right lobe plus the middle hepatic vein as measured intraoperatively (group 1).

CONCLUSIONS

The weight of the right liver lobe graft in a living-donor transplantation is less than that calculated by preoperative computed tomography, and the inclusion of the middle hepatic vein in the right liver lobe graft resulted in a statistically significant decrease in this difference.

Clinical significance of right hepatectomy along the main portal fissure on donors in living donor liver transplantation

There might be discordance between inter-lobar borders of the main portal fissure (MPF) using the middle hepatic vein (MHV) and of the portal segmentation. Forty-five living donors who underwent right hepatectomy for the adult recipients from 2007 to 2011 in a tertiary hospital were retrospectively analyzed. The donors were classified into conventional right hepatectomy along the MPF (cRL group, n = 26) and modified right hepatectomy along right-side shifted transection plane from the MPF (mRL group, n = 19). The cRL donors had higher postoperative peak level of INR (1.84 vs. 1.62; P = 0.022), and bilirubin (3.37 mg/dl vs. 2.74 mg/dl; P = 0.065) than the mRL donors. cRL donors experienced greater depression of platelet count (144 per nL vs. 168 per nL; P = 0.042) and enlargement of splenic volume (52% vs. 37%; P = 0.025) than mRL donors for 7 days after hepatectomy. The regeneration of the left lateral sector was more accelerated in the cRL donors than the mRL donors for postoperative 3 months (148% vs. 84%; P = 0.015). There were no differences in the post-transplant graft function, incidence of complications, and graft survival rates between the two groups of recipients (P > 0.05). This study suggests that the conventional right hepatectomy along the MHV might increase donor risk by reducing parenchymal liver volume of the segment IV.

Right lobe living-donor liver transplantation with or without middle hepatic vein: a meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to compare outcomes after right-lobe living-donor liver transplantation (LDLT) with or without the middle hepatic vein (MHV).

METHODS

Studies were identified through a computerized search of Pubmed, Embase, Ovid, the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials, the Cochrane Library database, and the Web of Science. Two reviewers independently assessed the quality of each study and abstracted outcome data. We extracted data for liver functional recovery in donors, donor hospital stay, donor complications and liver functional recovery in recipients. We synthesized published data using random-effects and fixed-effect models, expressing results as weighted mean differences (WMD) or relative risk (RR).

RESULTS

The 11 included eligible studies came from medical centers worldwide. Significant differences between "with MHV" versus "without MHV" groups were not observed for liver functional recovery (P=.08; WMD=-2.88), donor hospital stay (P=.00; WMD=0.00), or donor complications (P=.90; RR=1.02). However, our meta-analysis showed a significant benefit for recipients liver functional recovery favoring the MHV group (P=.02; WMD=-33.06).

CONCLUSIONS

Our meta-analysis discovered that right lobes with MHV not only experienced better liver functional recovery in recipients, but also caused no greater harm or risk to donors.

Emergency re-routing of anterior sector venous outflow for right lobe living donor liver transplantation including the middle hepatic vein

BACKGROUND

Controversy remains over whether the middle hepatic vein should be included in the liver graft in right liver living donor liver transplantation. Congestion in the anterior sector of a right liver graft can cause graft malfunction, which is especially devastating in the case of a graft with marginal size in relation to recipient body size on top of poor pre-transplant recipient status. The case we report here highlighted the importance of the middle hepatic vein in right liver living donor liver transplantation.

METHODS

We illustrated the rectification of outflow obstruction of the middle hepatic vein in the anterior sector of right liver graft caused by technical error during transplantation. The rectification was performed with emergency re-routing using an artificial conduit.

RESULT

Congestion in the anterior sector of the graft improved immediately and the patient's postoperative liver function test results improved gradually.

CONCLUSIONS

The middle hepatic vein is important for effective drainage of the anterior sector of a right liver graft. The re-routing technique described in the report can also be applied to cases in which the middle hepatic vein is injured during hepatectomy requiring immediate reconstruction.

Small for size syndrome following living donor and split liver transplantation

The field of liver transplantation is limited by the availability of donor organs. The use of living donor and split cadaveric grafts is one potential method of expanding the donor pool. However, primary graft dysfunction can result from the use of partial livers despite the absence of other causes such as vascular obstruction or sepsis. This increasingly recognised phenomenon is termed “Small-for-size syndrome” (SFSS). Studies in animal models and humans have suggested portal hyperperfusion of the graft combined with poor venous outflow and reduced arterial flow might cause sinusoidal congestion and endothelial dysfunction. Graft related factors such as graft to recipient body weight ratio < 0.8, impaired venous outflow, steatosis > 30% and prolonged warm/cold ischemia time are positively predictive of SFSS. Donor related factors include deranged liver function tests and prolonged intensive care unit stay greater than five days. Child-Pugh grade C recipients are at relatively greater risk of developing SFSS. Surgical approaches to prevent SFSS fall into two categories: those targeting portal hyperperfusion by reducing inflow to the graft, including splenic artery modulation and portacaval shunts; and those aiming to relieve parenchymal congestion. This review aims to examine the controversial diagnosis of SFSS, including current strategies to predict and prevent its occurrence. We will also consider whether such interventions could jeopardize the graft by compromising regeneration.

Hepatic venous drainage: how much can we learn from imaging studies? Anatomic-functional classification derived from three-dimensional computed tomography reconstructions

BACKGROUND

The knowledge of "venous dominance" is essential to prevent serious venous congestion in live donor liver transplantation and extended liver resections.

AIMS

The purpose of our study was to delineate our proposed anatomic-functional classification of hepatic venous drainage.

METHODS

One hundred forty consecutive live liver donor candidates underwent three-dimensional computed tomography reconstructions and three-dimensional virtual hepatectomies. Five different venous dominance types were defined on drainage volumes or territories. "Risky" configurations were identified and classified.

RESULTS

The right hepatic vein (RHV) was dominant for the entire liver and right hemiliver (RHH) in most (83.5%) cases irrespective of the presence of inferior (accessory) hepatic veins (IHVs). The middle hepatic vein (MHV) was dominant for the total liver (TL) in 15.5% of cases and for the RHH in 27% of cases. The left hepatic vein was almost always (92%) dominant for the left hemiliver. When associated with a large IHV drainage volume, a RHV/IHV complex dominant for the TL led to a RHH dominant MHV (mean 59.5%RHH) if the IHV was not reconstructed.

CONCLUSIONS

Our proposed anatomic-functional classification provides a valuable insight into hepatic vein dominance patterns. RHH venous drainage patterns at "high risk" for venous congestion include (1) a dominant MHV for the TL and (2) a dominant RHV/IHV complex with a large IHV drainage volume.

Routine microsurgical biliary reconstruction decreases early anastomotic complications in living donor liver transplantation

Biliary reconstruction using a microsurgical technique in living donor liver transplantation was routinely performed on 88 grafts primarily transplanted into 85 patients. All procedures were performed under a microscope by a single microsurgeon. Except for biliary atresia and Alagille syndrome, duct-to-duct reconstruction was performed. Stents were not used. The outcomes with microsurgical biliary reconstruction (MB) were compared with the outcomes of a cohort of 86 grafts in 85 patients that underwent conventional biliary reconstruction (CB). The identification of complications included only up to 12 months of follow-up for each recipient in both groups. The average graft duct sizes were 2.8 mm for MB and 3.4 mm for CB. Most complications occurred in the first 15 cases with MB, and these cases were considered to constitute the learning curve phase. The MB complication rate was 46.7% in the first 15 cases, 20.0% in the next 15 cases, and 5.4% in the last 55 cases. When the learning curve phase was excluded, the overall complication rate over time with MB (8.9%) was significantly lower than that with CB (21.9%). CB increased the risk of biliary complications by 2.5 times (relative risk: 2.5; attributable risk: 128; odds ratio: 2.9). In conclusion, routine MB is a technical innovation that leads to decreased early anastomotic complications in living donor liver transplantation.

Use of middle hepatic vein in right lobe living donor liver transplantation

The harvesting of the middle hepatic vein (MHV) with the right lobe graft for living-donor liver transplantation allows an optimal venous drainage for the recipient; however, it is an extensive operation for the donor. This is a prospective, nonrandomized study evaluating liver functions and early clinical outcome in donors undergoing right hepatectomy with or without MHV harvesting. From August 2005 to July 2007, a total of 100 donor right hepatectomies were performed with (n = 49) or without (n = 51) the inclusion of the MHV. The decision to take MHV was based on an algorithm that considers various donor and recipient factors. There was no donor mortality in donors in either group. Overall complication rate was higher in MHV (+) donor group, however when remnant liver volume was kept above 30%, complication rates were similar between the groups. The results of this study show that right hepatectomy including the MHV neither affects morbidity nor impairs early liver function in donors when remnant volume is kept above 30%. The decision, therefore, of the extent of right lobe donor hepatectomy should be tailored to the particular conditions considering the graft quality and metabolic demand of the recipient.

Preservation of recipient middle hepatic vein for drainage of anterior sector veins in adult-to-adult living-donor liver transplantation

The inclusion of donor middle hepatic vein (MHV) in right-lobe living-donor grafts and the need for reconstruction of the MHV tributaries have long been controversial areas in living-donor liver transplantation. We report technical details in restoration of venous drainage of the anterior sector (segments V and VIII) of the right lobe of the liver graft using a preserved MHV from the recipient liver, and address the issue of reconstruction of donor MHV tributaries without use of an interposition graft. We review clinical situations in which restoration of outflow drainage of the anterior segment of the liver graft should be considered.

Liver graft regeneration in right lobe adult living donor liver transplantation

Optimal portal flow is one of the essentials in adequate liver function, graft regeneration and outcome of the graft after right lobe adult living donor liver transplantation (ALDLT). The relations among factors that cause sufficient liver graft regeneration are still unclear. The aim of this study is to evaluate the potential predisposing factors that encourage liver graft regeneration after ALDLT. The study population consisted of right lobe ALDLT recipients from Chang Gung Memorial Hospital-Kaohsiung Medical Center, Taiwan. The records, preoperative images, postoperative Doppler ultrasound evaluation and computed tomography studies performed 6 months after transplant were reviewed. The volume of the graft 6 months after transplant divided by the standard liver volume was calculated as the regeneration ratio. The predisposing risk factors were compiled from statistical analyses and included age, recipient body weight, native liver disease, spleen size before transplant, patency of the hepatic venous graft, graft weight-to-recipient weight ratio (GRWR), posttransplant portal flow, vascular and biliary complications and rejection. One hundred forty-five recipients were enrolled in this study. The liver graft regeneration ratio was 91.2 +/- 12.6% (range, 58-151). The size of the spleen (p = 0.00015), total portal flow and GRWR (p = 0.005) were linearly correlated with the regeneration rate. Patency of the hepatic venous tributary reconstructed was positively correlated to graft regeneration and was statistically significant (p = 0.017). Splenic artery ligation was advantageous to promote liver regeneration in specific cases but splenectomy did not show any positive advantage. Spleen size is a major factor contributing to portal flow and may directly trigger regeneration after transplant. Control of sufficient portal flow and adequate hepatic outflow are important factors in graft regeneration.

Liver Transplantation in Asia: Past, Present and Future

With the technical advances and improvements in perioperative management and immunosuppressants, liver transplantation is the standard treatment for patients with end-stage liver diseases. In Asia, a shortage of deceased donor liver grafts is the universal problem to be faced with in all transplant centres. Many surgical innovations are then driven to counteract this problem. This review focuses on 3 issues that denote the development of liver transplantation in Asian countries. These include living donor liver transplantation (LDLT), split liver transplantation (SLT) and liver transplantation for hepatocellular carcinoma (HCC). Minimal graft weight, types of liver graft to donate and the inclusion of the middle hepatic vein with the graft are the main issues to be established in LDLT. The rapid growth and wide dissemination of LDLT has certainly alleviated the supply-and-demand problem of liver grafts in Asia. SLT is another attractive approach. Technical expertise, donor selection and graft allocation are the main determinants for its success. Liver transplantation plays a key role in the management of HCC in Asia. LDLT would be the main strategy in this aspect. The issue of extending the selection criteria for HCC patients for LDLT is still controversial. On the whole, future developments to increase the donor pool for the expanding recipient need in Asia would involve transplantation from non-heart beating donor and ABO incompatible transplantation.

Territorial belonging of the middle hepatic vein in living liver donor candidates evaluated by three-dimensional computed tomographic reconstruction and virtual liver resection

Background

Postoperative venous congestion can lead to graft and remnant liver failure in living donor liver transplantation. This study was designed to delineate ‘territorial belonging’ of the middle hepatic vein (MHV) and to identify hepatic venous anatomy at high risk of outflow congestion.

Methods

MHV belonging patterns for right (RHL) and left (LHL) hemilivers were evaluated by three-dimensional computed tomographic reconstruction and virtual hepatectomy in 138 consecutive living liver donor candidates.

Results

The right hepatic vein (RHV) was dominant in 84·1 per cent and an accessory inferior hepatic vein (IHV) was present in 47·1 per cent of livers. Three MHV belonging types were identified for the RHL. Strong and complex MHV types A and C were associated with large RHL venous congestion. The MHV belonged to the LHL in 65·9 per cent, draining 37 per cent of this hemiliver. In virtual liver resections, left MHV type D was a risk category for small left liver remnants.

Conclusion

MHV territorial belonging types A and C were identified as high risk for RHL venous congestion. Their presence should prompt consideration of either inclusion of the MHV with the right graft or reconstruction of its tributaries, and preservation of IHV territory.